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Now, in order to account for the intuitive differences between conceptual and sensory representations, representationalists appeal to their structural or functional differences. Dretske (1995), for example, distinguishes experiences and thoughts on the basis of the origin and nature of their functions: an experience of a property 'P' is a state of a system whose evolved function is to indicate the presence of 'P' in the environment; a thought representing the property 'P', on the other hand, is a state of a system whose assigned (learned) function is to calibrate the output of the experiential system. Rey (1991) takes both thoughts and experiences to be relations to sentences in the language of thought, and distinguishes them on the basis of (the functional roles of) such sentences' constituent predicates. Lycan (1987, 1996) distinguishes them in terms of their functional-computational profiles. Tye (2000) distinguishes them in terms of their functional roles and the intrinsic structure of their vehicles: thoughts are representations in a language-like medium, whereas experiences are image-like representations consisting of 'symbol-filled arrays.' (The account of mental images in Tye 1991.)


Phenomenalists tend to make use of the same sorts of features (function, intrinsic structure) in explaining some of the intuitive differences between thoughts and experiences; but they do not suppose that such features exhaust the differences between phenomenal and non-phenomenal representations. For the phenomenalism, it is the phenomenal properties of experiences - Qualia themselves - that constitute the fundamental difference between experience and thought. Peacocke (1992), for example, develops the notion of a perceptual 'scenario' (an assignment of phenomenal properties to coordinates of a three-dimensional egocentric space), whose content is 'correct' (a semantic property) if in the corresponding 'scene' (the portion of the external world represented by the scenario) properties are distributed as their phenomenal analogues are in the scenario.

Another sort of representation championed by phenomenalists (e.g., Block, Chalmers (2003) and Loar (1996)) is the 'phenomenal concept' - a conceptual/phenomenal hybrid consisting of a phenomenological 'sample' (an image or an occurrent sensation) integrated with (or functioning as) a conceptual component. Phenomenal concepts are postulated to account for the apparent fact (among others) that, as McGinn (1991) puts it, 'you cannot form [introspective] concepts of conscious properties unless you yourself instantiate those properties.' One cannot have a phenomenal concept of a phenomenal property 'P', and, hence, phenomenal beliefs about P, without having experience of 'P', because 'P' itself is (in some way) constitutive of the concept of 'P'. (Jackson 1982, 1986 and Nagel 1974.)

Though imagery has played an important role in the history of philosophy of mind, the important contemporary literature on it is primarily psychological. In a series of psychological experiments done in the 1970s (summarized in Kosslyn 1980 and Shepard and Cooper 1982), subjects' response time in tasks involving mental manipulation and examination of presented figures was found to vary in proportion to the spatial properties (size, orientation, etc.) of the figures presented. The question of how these experimental results are to be explained has kindled a lively debate on the nature of imagery and imagination.

Kosslyn (1980) claims that the results suggest that the tasks were accomplished via the examination and manipulation of mental representations that they have spatial properties - i.e., pictorial representations, or images. Others, principally Pylyshyn (1979, 1981, 2003), argue that the empirical facts can be explained in terms exclusively of discursive, or propositional representations and cognitive processes defined over them. (Pylyshyn takes such representations to be sentences in a language of thought.)

The idea that pictorial representations are literally pictures in the head is not taken seriously by proponents of the pictorial view of imagery. The claim is, rather, that mental images represent in a way that is relevantly like the way pictures represent. (Attention has been focussed on visual imagery - hence the designation 'pictorial'; though of course there may imagery in other modalities - auditory, olfactory, etc. - as well.)

The distinction between pictorial and discursive representation can be characterized in terms of the distinction between analog and digital representation (Goodman 1976). This distinction has itself been variously understood (Fodor & Pylyshyn 1981, Goodman 1976, Haugeland 1981, Lewis 1971, McGinn 1989), though a widely accepted construal is that analog representation is continuous (i.e., in virtue of continuously variable properties of the representation), while digital representation is discrete (i.e., in virtue of properties a representation either has or doesn't have) (Dretske 1981). (An analog/digital distinction may also be made with respect to cognitive processes. (Block 1983.)) On this understanding of the analog/digital distinction, imagistic representations, which represent in virtue of properties that may vary continuously (such as more or less bright, loud, vivid, etc.), would be analog, while conceptual representations, whose properties do not vary continuously (a thought cannot be more or less about Elvis: either it is or it is not) would be digital.

It might be supposed that the pictorial/discursive distinction is best made in terms of the phenomenal/nonphenomenal distinction, but it is not obvious that this is the case. For one thing, there may be nonphenomenal properties of representations that vary continuously. Moreover, there are ways of understanding pictorial representation that presuppose neither phenomenality nor analogicity. According to Kosslyn (1980, 1982, 1983), a mental representation is 'quasi-pictorial' when every part of the representation corresponds to a part of the object represented, and relative distances between parts of the object represented are preserved among the parts of the representation. But distances between parts of a representation can be defined functionally rather than spatially - for example, in terms of the number of discrete computational steps required to combine stored information about them.

Tye (1991) proposes a view of images on which they are hybrid representations, consisting both of the pictorial and discursive elements. On Tye's account, images are '(labelled) interpreted symbol-filled arrays.' The symbols represent discursively, while their arrangement in arrays has representational significance (the location of each 'cell' in the array represents a specific viewer-centred 2-Dimensional location on the surface of the imagined object)

The contents of mental representations are typically taken to be abstract objects (properties, relations, propositions, sets, etc.). A pressing question, especially for the naturalist, is how mental representations come to have their contents. Here the issue is not how to naturalize content (abstract objects can't be naturalized), but, rather, how to provide a naturalistic account of the content-determining relations between mental representations and the abstract objects they express. There are two basic types of contemporary naturalistic theories of content-determination, causal-informational and functional.

Causal-informational theories (Dretske 1981, 1988, 1995) hold that the content of a mental representation is grounded in the information it carries about what does (Devitt 1996) or would (Fodor 1987, 1990) cause it to occur. There is, however, widespread agreement that causal-informational relations are not sufficient to determine the content of mental representations. Such relations are common, but representation is not. Tree trunks, smoke, thermostats and ringing telephones carry information about what they are causally related to, but they do not represent (in the relevant sense) what they carry information about. Further, a representation can be caused by something it does not represent, and can represent something that has not caused it.

The Asymmetric Dependency Theory distinguishes merely informational relations from representational relations on the basis of their higher-order relations to each other: informational relations depend upon representational relations, but not vice-versa. For example, if tokens of a mental state type are reliably caused by horses, cows-on-dark-nights, zebras-in-the-mist and Great Danes, then they carry information about horses, etc. If, however, such tokens are caused by cows-on-dark-nights, etc. because they were caused by horses, but not vice versa, then they represent horses.

According to Teleological Theories, representational relations are those a representation-producing mechanism has the selected (by evolution or learning) function of establishing. For example, zebra-caused horse-representations do not mean zebra, because the mechanism by which such tokens are produced has the selected function of indicating horses, not zebras. The horse-representation-producing mechanism that responds to zebras is malfunctioning.

Functional theories (Block 1986, Harman 1973), hold that the content of a mental representation is grounded in its (causal computational, inferential) relations to other mental representations. They differ on whether relata should include all other mental representations or only some of them, and on whether to include external states of affairs. The view that the content of a mental representation is determined by its inferential/computational relations with all other representations is holism; the view it is determined by relations to only some other mental states is localism (or molecularism). (The view that the content of a mental state depends on none of its relations to other mental states is atomism.) Functional theories that recognize no content-determining external relata have been called solipsistic (Harman 1987). Some theorists posit distinct roles for internal and external connections, the former determining semantic properties analogous to sense, the latter determining semantic properties analogous to reference (McGinn 1982, Sterelny 1989)

[Reductive] representationalists (Dretske, Lycan, Tye), usually take one or another of these theories to provide an explanation of the (Non-conceptual) content of experiential states. They thus tend to be Externalists about phenomenological as well as conceptual content. Phenomenalists and non-deductive representationalists (Block, Chalmers, Loar, Peacocke, Siewert), on the other hand, take it that the representational content of such states is (at least in part) determined by their intrinsic phenomenal properties. Further, those who advocate a phenomenology-based approach to conceptual content (Horgan and Tiensen, Loar, Pitt, Searle, Siewert) also seem to be committed to Internalist individuation of the content (if not the reference) of such states.

Generally, those who, like informational theorists, think relations to one's (natural or social) environment are (at least partially) determinative of the content of mental representations are Externalists, whereas of those who, like some proponents of functional theories, think contentually representative, if only to be determined by an individual's intrinsic properties alone, are internalists (or individualists).

This issue is widely taken to be of central importance, since psychological explanation, whether commonsense or scientific, is supposed to be both causal and content-based. (Beliefs and desires cause the behaviours they do because they have the contents they do. For example, the desire that one have a beer and the beliefs that there is beer in the refrigerator and that the refrigerator is in the kitchen may explain one's getting up and going to the kitchen.) If, however, a mental representation's having a particular content is due to factors extrinsic to it, it is unclear how its having that content could determine its causal powers, which, arguably, must be intrinsic. Some who accept the standard arguments for externalism have argued that internal factors determine a component of the content of a mental representation. They say that mental representations have both 'narrow' content (determined by intrinsic factors) and 'wide' or 'broad' content (determined by narrow content plus extrinsic factors). (This distinction may be applied to the sub-personal representations of cognitive science as well as to those of commonsense psychology.

Narrow content has been variously construed. Putnam (1975), Fodor (1982)), and Block (1986), for example, seem to understand it as something like de dicto content (i.e., Frégean sense, or perhaps character, à la Kaplan 1989). On this construal, narrow content is context-independent and directly expressible. Fodor (1987) and Block (1986), however, have also characterized narrow content as radically inexpressible. On this construal, narrow content is a kind of proto-content, or content-determinant, and can be specified only indirectly, via specifications of context/wide-content pairings. On both construal, narrow contents are characterized as functions from context to (wide) content. The narrow content of a representation is determined by properties intrinsic to it or its possessor such as its syntactic structure or its intra-mental computational or inferential role (or its phenomenology.

Burge (1986) has argued that causation-based worries about externalist individuation of psychological content, and the introduction of the narrow notion, are misguided. Fodor (1994, 1998) has more recently urged that of a familiarization for adjusting to an orderly scientific psychological, however, this might not need narrow content in order to supply naturalistic (causal) explanations of human cognition and action, since the sorts of cases they were introduced to handle, viz., Twin-Earth cases and Frége cases, are nomologically either impossible or dismissible as exceptions to non-rigid and less of a sternful psychological law.

The leading contemporary version of the Representational Theory of Mind, the Computational Theory of Mind, claims that the brain is a kind of computer and that mental processes are computations. According to the computational theory of mind, cognitive states are constituted by computational relations to mental representations of various kinds, and cognitive processes are sequences of such states. The computational theory of mind and the representational theory of mind, may by attempting to explain all psychological states and processes in terms of mental representation. In the course of constructing detailed empirical theories of human and animal cognition and developing models of cognitive processes' implementable in artificial information processing systems, cognitive scientists have proposed a variety of types of mental representations. While some of these may be suited to be mental relata of commonsense psychological states, some - so-called 'subpersonal' or 'sub-doxastic' representations - are not. Though many philosophers believe that computational theory of mind can provide the best scientific explanations of cognition and behaviour, there is disagreement over whether such explanations will vindicate the commonsense psychological explanations of prescientific representational theory of mind.

According to Stich's (1983) Syntactic Theory of Mind, for example, computational theories of psychological states should concern themselves only with the formal properties of the objects those states are relations to. Commitment to the explanatory relevance of content, however, is for most cognitive scientists fundamental (Fodor 1981, Pylyshyn 1984, Von Eckardt 1993). That mental processes are computations, which computations are rule-governed sequences of semantically evaluable objects, and that the rules apply to the symbols in virtue of their content, are central tenets of mainstream cognitive science.

Explanations in cognitive science appeal to a many different kinds of mental representation, including, for example, the 'mental models' of Johnson-Laird 1983, the 'retinal arrays,' 'primal sketches' and '2½ -Dimensional sketches' of Marr, 1982 'frames' of Minsky 1974, the 'sub-symbolic' structures of Smolensky 1989, the 'quasi-pictures' of Kosslyn 1980, and the 'interpreted symbol-filled arrays' of Tye 1991 - in addition to representations that may be appropriate to the explanation of commonsense psychological states. Computational explanations have been offered of, among other mental phenomena, belief (Fodor 1975, Field 1978), visual perception (Marr 1982, Osherson, et al. 1990), rationality (Newell and Simon 1972, Fodor 1975, Johnson-Laird and Wason 1977), language learning and (Chomsky 1965, Pinker 1989), and musical comprehension (Lerdahl and Jackendoff 1983).

A fundamental disagreement among proponents of computational theory of mind concerns the realization of personal-level representations (e.g., thoughts) and processes (e.g., inferences) in the brain. The central debate here is between proponents of Classical Architectures and proponents of Conceptionist Architectures.

The classicists (e.g., Turing 1950, Fodor 1975, Fodor and Pylyshyn 1988, Marr 1982, Newell and Simon 1976) hold that mental representations are symbolic structures, which typically have semantically evolvable constituents, and that mental processes are rule-governed manipulations of them that are sensitive to their constituent structure. The conceptionists (e.g., McCulloch & Pitts 1943, Rumelhart 1989, Rumelhart and McClelland 1986, Smolensky 1988) hold that mental representations are realized by patterns of activation in a network of simple processors ('nodes') and that mental processes consist of the spreading activation of such patterns. The nodes themselves are, typically, not taken to be semantically evaluable; nor do the patterns have semantically evaluable constituents. (Though there are versions of Connectionism - 'localist' versions - on which individual nodes are taken to have semantic properties (e.g., Ballard 1986, Ballard & Hayes 1984).) It is arguable, however, that localist theories are neither definitive nor representative of the Conceptionist program (Smolensky 1988, 1991, Chalmers 1993).

Classicists are motivated (in part) by properties thought seems to share with language. Fodor's Language of Thought Hypothesis (LOTH) (Fodor 1975, 1987), according to which the system of mental symbols constituting the neural basis of thought is structured like a language, provides a well-worked-out version of the classical approach as applied to commonsense psychology. According to the language of thought hypotheses, the potential infinity of complex representational mental states is generated from a finite stock of primitive representational states, in accordance with recursive formation rules. This combinatorial structure accounts for the properties of productivity and systematicity of the system of mental representations. As in the case of symbolic languages, including natural languages (though Fodor does not suppose either that the language of thought hypothesis explains only linguistic capacities or that only verbal creatures have this sort of cognitive architecture), these properties of thought are explained by appeal to the content of the representational units and their combinability into contentful complexes. That is, the semantics of both language and thought is compositional: the content of a complex representation is determined by the contents of its constituents and their structural configuration.

Connectionists are motivated mainly by a consideration of the architecture of the brain, which apparently consists of layered networks of interconnected neurons. They argue that this sort of architecture is unsuited to carrying out classical serial computations. For one thing, processing in the brain is typically massively parallel. In addition, the elements whose manipulation drives computation in Conceptionist networks (principally, the connections between nodes) are neither semantically compositional nor semantically evaluable, as they are on the classical approach. This contrast with classical computationalism is often characterized by saying that representation is, with respect to computation, distributed as opposed to local: representation is local if it is computationally basic; and distributed if it is not. (Another way of putting this is to say that for classicists mental representations are computationally atomic, whereas for connectionists they are not.)

Moreover, connectionists argue that information processing as it occurs in Conceptionist networks more closely resembles some features of actual human cognitive functioning. For example, whereas on the classical view learning involves something like hypothesis formation and testing (Fodor 1981), on the Conceptionist model it is a matter of evolving distribution of 'weight' (strength) on the connections between nodes, and typically does not involve the formulation of hypotheses regarding the identity conditions for the objects of knowledge. The Conceptionist network is 'trained up' by repeated exposure to the objects it is to learn to distinguish; and, though networks typically require many more exposures to the objects than do humans, this seems to model at least one feature of this type of human learning quite well.

Further, degradation in the performance of such networks in response to damage is gradual, not sudden as in the case of a classical information processor, and hence more accurately models the loss of human cognitive function as it typically occurs in response to brain damage. It is also sometimes claimed that Conceptionist systems show the kind of flexibility in response to novel situations typical of human cognition - situations in which classical systems are relatively 'brittle' or 'fragile.'

Some philosophers have maintained that Connectionism entails that there are no propositional attitudes. Ramsey, Stich and Garon (1990) have argued that if Conceptionist models of cognition are basically correct, then there are no discrete representational states as conceived in ordinary commonsense psychology and classical cognitive science. Others, however (e.g., Smolensky 1989), hold that certain types of higher-level patterns of activity in a neural network may be roughly identified with the representational states of commonsense psychology. Still others, argue that language-of-thought style representation is both necessary in general and realizable within Conceptionist architectures. (MacDonald & MacDonald 1995 collects the central contemporary papers in the classicist/Conceptionist debate, and provides useful introductory material as well.

Whereas Stich (1983) accepts that mental processes are computational, but denies that computations are sequences of mental representations, others accept the notion of mental representation, but deny that computational theory of mind provides the correct account of mental states and processes.

Van Gelder (1995) denies that psychological processes are computational. He argues that cognitive systems are dynamic, and that cognitive states are not relations to mental symbols, but quantifiable states of a complex system consisting of (in the case of human beings) a nervous system, a body and the environment in which they are embedded. Cognitive processes are not rule-governed sequences of discrete symbolic states, but continuous, evolving total states of dynamic systems determined by continuous, simultaneous and mutually determining states of the systems' components. Representation in a dynamic system is essentially information-theoretic, though the bearers of information are not symbols, but state variables or parameters.

Horst (1996), on the other hand, argues that though computational models may be useful in scientific psychology, they are of no help in achieving a philosophical understanding of the intentionality of commonsense mental states. computational theory of mind attempts to reduce the intentionality of such states to the intentionality of the mental symbols they are relations to. But, Horst claims, the relevant notion of symbolic content is essentially bound up with the notions of convention and intention. So the computational theory of mind involves itself in a vicious circularity: the very properties that are supposed to be reduced are (tacitly) appealed to in the reduction.

To say that a mental object has semantic properties is, paradigmatically, to say that it may be about, or be true or false of, an object or objects, or that it may be true or false simpliciter. Suppose I think that ocelots take snuff. I am thinking about my wish of placing a dot or period, if only to complete of this book, and if what I think of such an aspiring endeavour becomes is true, so, that, within its individualized participation, is then that my thought is true. According to representational theory of mind such states are to be explained as relations between agents and mental representations. To think that ocelots take snuff is to token in some way a mental representation whose content is that ocelots take snuff. On this view, the semantic properties of mental states are the semantic properties of the representations they are relations to.

Linguistic acts seem to share such properties with mental states. Suppose I say that ocelots take snuff. I am talking about ocelots, and if what I say of them (that they take snuff) is true of them, then my utterance is true. Now, to say that ocelots take snuff is (in part) to utter a sentence that means that ocelots take snuff. Many philosophers have thought that the semantic properties of linguistic expressions are inherited from the intentional mental states they are conventionally used to express. On this view, the semantic properties of linguistic expressions are the semantic properties of the representations that are the mental relata of the states they are conventionally used to express.

It is also widely held that in addition to having such properties as reference, truth-conditions and truth - so-called extensional properties - expressions of natural languages also have intensional properties, in virtue of expressing properties or propositions - i.e., in virtue of having meanings or senses, where two expressions may have the same reference, truth-conditions or truth value, yet express different properties or propositions (Frége 1892/1997). If the semantic properties of natural-language expressions are inherited from the thoughts and concepts they express (or vice versa, or both), then an analogous distinction may be appropriate for mental representations.

Søren Aabye Kierkegaard (1813-1855), a Danish religious philosopher, whose concern with individual existence, choice, and commitment profoundly influenced modern theology and philosophy, especially existentialism.

Søren Kierkegaard wrote of the paradoxes of Christianity and the faith required to reconcile them. In his book Fear and Trembling, Kierkegaard discusses Genesis 22, in which God commands Abraham to kill his only son, Isaac. Although God made an unreasonable and immoral demand, Abraham obeyed without trying to understand or justify it. Kierkegaard regards this 'leap of faith' as the essence of Christianity.

Kierkegaard was born in Copenhagen on May 15, 1813. His father was a wealthy merchant and strict Lutheran, whose gloomy, guilt-ridden piety and vivid imagination strongly influenced Kierkegaard. Kierkegaard studied theology and philosophy at the University of Copenhagen, where he encountered Hegelian philosophy and reacted strongly against it. While at the university, he ceased to practice Lutheranism and for a time led an extravagant social life, becoming a familiar figure in the theatrical and café society of Copenhagen. After his father's death in 1838, however, he decided to resume his theological studies. In 1840 he became engaged to the 17-year-old Regine Olson, but almost immediately he began to suspect that marriage was incompatible with his own brooding, complicated nature and his growing sense of a philosophical vocation. He abruptly broke off the engagement in 1841, but the episode took on great significance for him, and he repeatedly alluded to it in his books. At the same time, he realized that he did not want to become a Lutheran pastor. An inheritance from his father allowed him to devote himself entirely to writing, and in the remaining 14 years of his life he produced more than 20 books.

Kierkegaard's work is deliberately unsystematic and consists of essays, aphorisms, parables, fictional letters and diaries, and other literary forms. Many of his works were originally published under pseudonyms. He applied the term existential to his philosophy because he regarded philosophy as the expression of an intensely examined individual life, not as the construction of a monolithic system in the manner of the 19th-century German philosopher Georg Wilhelm Friedrich Hegel, whose work he attacked in Concluding Unscientific Postscript (1846: translations, 1941). Hegel claimed to have achieved a complete rational understanding of human life and history; Kierkegaard, on the other hand, stressed the ambiguity and paradoxical nature of the human situation. The fundamental problems of life, he contended, defy rational, objective explanation; the highest truth is subjective.

Kierkegaard maintained that systematic philosophy not only imposed a false perspective on human existence but that it also, by explaining life in terms of logical necessity, becomes a means of avoiding choice and responsibility. Individuals, he believed, create their own natures through their choices, which must be made in the absence of universal, objective standards. The validity of a choice can only be determined subjectively.

In his first major work, Either/Or, Kierkegaards described two spheres, or stages of existence, that the individual may choose: the aesthetic and the ethical. The aesthetic way of life is a refined hedonism, consisting of a search for pleasure and a cultivation of a mood. The aesthetic individual constantly seeks variety and novelty in an effort to stave off boredom but eventually must confront boredom and despair. The ethical way of life involves an intense, passionate commitment to duty, to unconditional social and religious obligations. In his later works, such as Stages on Life's Way (1845: Translations, 1940), Kierkegaard discerned in this submission to duty a loss of individual responsibility, and he proposed a third stage, the religious, in which one submits to the will of God but in doing so finds authentic freedom. In "Fear and Trembling" (1846; Translated, 1941) Kierkegaard focussed on God's command that Abraham sacrifice his son Isaac (Genesis 22: 1-19), an act that violates Abraham's ethical convictions. Abraham proves his faith by resolutely setting out to obey God's command, even though he cannot understand it. This 'suspension of the ethical,' as Kierkegaard called it, allows Abraham to achieve an authentic commitment to God. To avoid ultimate despair, the individual must make a similar 'leap of faith' into a religious life, which is inherently paradoxical, mysterious, and full of risk. One is called to it by the feeling of dread (The Concept of Dread, 1844; translations, 1944), which is ultimately a fear of nothingness.

Toward the end of his life Kierkegaard was involved in bitter controversies, especially with the established Danish Lutheran church, which he regarded as worldly and corrupt. His later works, such as The Sickness Unto Death (1849: translations, 1941), reflects an increasingly sombre view of Christianity, emphasizing suffering as the essence of authentic faith. He also intensified his attack on modern European society, which he denounced in The Present Age (1846; translated 1940) for its lack of passion and for its quantitative values. The stress of his prolific writing and of the controversies in which he engaged gradually undermined his health; in October 1855 he fainted in the street, and he died in Copenhagen on November 11, 1855.

Kierkegaard's influence was at first confined to Scandinavia and to German-speaking Europe, where his work had a strong impact on Protestant Theology and on such writers as the 20th-century Austrian novelist Franz Kafka. As existentialism emerged as a general European movement after World War I, Kierkegaard's work was widely translated, and he was recognized as one of the seminal figures of modern culture.

Since scientists, during the nineteenth century were engrossed with uncovering the workings of external reality and seemingly knew of themselves that these virtually overflowing burdens of nothing, in that were about the physical substrates of human consciousness, the business of examining the distributive contribution in dynamic functionality and structural foundation of mind became the province of social scientists and humanists. Adolphe Quételet proposed a 'social physics' that could serve as the basis for a new discipline called sociology, and his contemporary Auguste Comte concluded that a true scientific understanding of the social reality was quite inevitable. Mind, in the view of these figures, was a separate and distinct mechanism subject to the lawful workings of a mechanical social reality.

More formal European philosophers, such as Immanuel Kant, sought to reconcile representations of external reality in mind with the motions of matter-based on the dictates of pure reason. This impulse was also apparent in the utilitarian ethics of Jerry Bentham and John Stuart Mill, in the historical materialism of Karl Marx and Friedrich Engels, and in the pragmatism of Charles Smith, William James and John Dewey. These thinkers were painfully aware, however, of the inability of reason to posit a self-consistent basis for bridging the gap between mind and matter, and each remains obliged to conclude that the realm of the mental exists only in the subjective reality of the individual.

The fatal flaw of pure reason is, of course, the absence of emotion, and purely explanations of the division between subjective reality and external reality, of which had limited appeal outside the community of intellectuals. The figure most responsible for infusing our understanding of the Cartesian dualism with contextual representation of our understanding with emotional content was the death of God theologian Friedrich Nietzsche 1844-1900. After declaring that God and 'divine will', did not exist, Nietzsche reified the 'existence' of consciousness in the domain of subjectivity as the ground for individual 'will' and summarily reducing all previous philosophical attempts to articulate the 'will to truth'. The dilemma, forth in, had seemed to mean, by the validation, . . . as accredited for doing of science, in that the claim that Nietzsche's earlier versions to the 'will to truth', disguises the fact that all alleged truths were arbitrarily created in the subjective reality of the individual and are expressed or manifesting the individualism of 'will'.

In Nietzsche's view, the separation between mind and matter is more absolute and total than previously been imagined. Based on the assumption that there is no really necessary correspondence between linguistic constructions of reality in human subjectivity and external reality, he deuced that we are all locked in 'a prison house of language'. The prison as he concluded it, was also a 'space' where the philosopher can examine the 'innermost desires of his nature' and articulate a new message of individual existence founded on 'will'.

Those who fail to enact their existence in this space, Nietzsche says, are enticed into sacrificing their individuality on the nonexistent altars of religious beliefs and democratic or socialists' ideals and become, therefore, members of the anonymous and docile crowd. Nietzsche also invalidated the knowledge claims of science in the examination of human subjectivity. Science, he said. Is not exclusive to natural phenomenons and favours reductionistic examination of phenomena at the expense of mind? It also seeks to reduce the separateness and uniqueness of mind with mechanistic descriptions that disallow and basis for the free exercise of individual will.

The mechanistic paradigms of the late in the nineteenth century where the one Einstein came to know when he studied physics. Most physicists believed that it represented an eternal truth, but Einstein was open to fresh ideas. Inspired by Mach's critical mind, he demolished the Newtonian ideas of space and time and replaced them with new, 'relativistic' notions.

Jean-Paul Sartre (1905-1980), was a French philosopher, dramatist, novelist, and political journalist, who was a leading exponent of existentialism. Jean-Paul Sartre helped to develop existential philosophy through his writings, novels, and plays. Much of Sartre's work focuses on the dilemma of choice faced by free individuals and on the challenge of creating meaning by acting responsibly in an indifferent world. In stating that 'man is condemned to be free,' Sartre reminds us of the responsibility that accompanies human decisions.

Sartre was born in Paris, June 21, 1905, and educated at the Écôle Normale Supérieure in Paris, the University of Fribourg in Switzerland, and the French Institute in Berlin. He taught philosophy at various lycées from 1929 until the outbreak of World War II, when he was called into military service. In 1940-41 he was imprisoned by the Germans; after his release, he taught in Neuilly, France, and later in Paris, and was active in the French Resistance. The German authorities, unaware of his underground activities, permitted the production of his antiauthoritarian play The Flies (1943: translations, 1946) and the publication of his major philosophic work Being and Nothingness (1943: translations, 1953). Sartre gave up teaching in 1945 and founded the political and literary magazine Les Temps Modernes, of which he became the editor in chief. Sartre was active after 1947 as an independent Socialist, critical of both the USSR and the United States in the so-called cold war years. Later, he supported Soviet positions but still frequently criticized Soviet policies. Most of his writing of the 1950s deals with literary and political problems. Sartre rejected the 1964 Nobel Prize in literature, explaining that to accept such an award would compromise his integrity as a writer.

Sartre's philosophic works combine the phenomenology of the German philosopher Edmund Husserl, the metaphysics of the German philosophers Georg Wilhelm Friedrich Hegel and Martin Heidegger, and the social theory of Karl Marx into a single view called existentialism. This view, which relates philosophical theory to life, literature, psychology, and political action, stimulated so much popular interest that existentialism became a worldwide movement.

In his early philosophic work, Being and Nothingness, Sartre conceived humans as beings who create their own world by rebelling against authority and by accepting personal responsibility for their actions, unaided by society, traditional morality, or religious faith. Distinguishing between human existence and the nonhuman world, he maintained that human existence is characterized by nothingness, that is, by the capacity to negate and rebel. His theory of an existential psychoanalysis asserted the inescapable responsibility of all individuals for their own decisions and made the recognition of one's absolute freedom of choice the necessary condition for authentic human existence. His plays and novels express the belief that freedom and acceptance of personal responsibility are the main values in life and that individuals must rely on their creative powers rather than on social or religious authority.

In his later philosophic work Critique of Dialectical Reason (1960: translations, 1976), Sartre's emphasis shifted from existentialist freedom and subjectivity to Marxist social determinism. Sartre argued that the influence of modern society over the individual is so great as to produce serialization, by which he meant loss of self. Individual power and freedom can only be regained through group revolutionary action. Despite this exhortation to revolutionary political activity, Sartre himself did not join the Communist Party, thus retaining the freedom to criticize the Soviet invasions of Hungary in 1956 and Czechoslovakia in 1968. He died in Paris, April 15, 1980.

The part of the theory of design or semiotics, that concerns the relationship between speakers and their signs. the study of the principles governing appropriate conversational moves is called general pragmatized, applied pragmatics treats of special kinds of linguistic interaction such as interviews and speech asking, nevertheless, the philosophical movement that has had a major impact on American culture from the late 19th century to the present. Pragmatism calls for ideas and theories to be tested in practice, by assessing whether acting upon the idea or theory produces desirable or undesirable results. According to pragmatists, all claims about truth, knowledge, morality, and politics must be tested in this way. Pragmatism has been critical of traditional Western philosophy, especially the notions that there are absolute truths and absolute values. Although pragmatism was popular for a time in France, England, and Italy, most observers believe that it encapsulates an American faith in know-how and practicality and an equally American distrust of abstract theories and ideologies.

Pragmatists regard all theories and institutions as tentative hypotheses and solutions. For this reason they believed that efforts to improve society, through such means as education or politics, must be geared toward problem solving and must be ongoing. Through their emphasis on connecting theory to practice, pragmatist thinkers attempted to transform all areas of philosophy, from metaphysics to ethics and political philosophy.

Pragmatism sought a middle ground between traditional ideas about the nature of reality and radical theories of nihilism and irrationalism, which had become popular in Europe in the late 19th century. Traditional metaphysics assumed that the world has a fixed, intelligible structure and that human beings can know absolute or objective truths about the world and about what constitutes moral behavior. Nihilism and irrationalism, on the other hand, denied those very assumptions and their certitude. Pragmatists today still try to steer a middle course between contemporary offshoots of these two extremes.

The ideas of the pragmatists were considered revolutionary when they first appeared. To some critics, pragmatism's refusal to affirm any absolutes carried negative implications for society. For example, pragmatists do not believe that a single absolute idea of goodness or justice exists, but rather than these concepts are changeable and depend on the context in which they are being discussed. The absence of these absolutes, critics feared, could result in a decline in moral standards. The pragmatists' denial of absolutes, moreover, challenged the foundations of religion, government, and schools of thought. As a result, pragmatism influenced developments in psychology, sociology, education, semiotics (the study of signs and symbols), and scientific method, as well as philosophy, cultural criticism, and social reform movements. Various political groups have also drawn on the assumptions of pragmatism, from the progressive movements of the early 20th century to later experiments in social reform.

Pragmatism is best understood in its historical and cultural context. It arose during the late 19th century, a period of rapid scientific advancement typified by the theories of British biologist Charles Darwin, whose theories suggested too many thinkers that humanity and society are in a perpetual state of progress. During this same period a decline in traditional religious beliefs and values accompanied the industrialization and material progress of the time. In consequence it became necessary to rethink fundamental ideas about values, religion, science, community, and individuality.

The three most important pragmatists are American philosophers' Charles Sanders Peirce, William James, and John Dewey. Peirce was primarily interested in scientific method and mathematics; His objective was to infuse scientific thinking into philosophy and society, and he believed that human comprehension of reality was becoming ever greater and that human communities were becoming increasingly progressive. Peirce developed pragmatism as a theory of meaning - in particular, the meaning of concepts used in science. The meaning of the concept 'brittle,' for example, is given by the observed consequences or properties that objects called 'brittle' exhibit. For Peirce, the only rational way to increase knowledge was to form mental habits that would test ideas through observation, experimentation, or what he called inquiry. Many philosophers known as logical positivists, a group of philosophers who have been influenced by Peirce, believed that our evolving species was fated to get ever closer to Truth. Logical positivists emphasize the importance of scientific verification, rejecting the assertion of positivism that personal experience is the basis of true knowledge.

James moved pragmatism in directions that Peirce strongly disliked. He generalized Peirce's doctrines to encompass all concepts, beliefs, and actions; he also applied pragmatist ideas to truth as well as to meaning. James was primarily interested in showing how systems of morality, religion, and faith could be defended in a scientific civilization. He argued that sentiment, as well as logic, is crucial to rationality and that the great issues of life - morality and religious belief, for example - are leaps of faith. As such, they depend upon what he called 'the will to believe' and not merely on scientific evidence, which can never tell us what to do or what is worthwhile. Critics charged James with relativism (the belief that values depend on specific situations) and with crass expediency for proposing that if an idea or action works the way one intends, it must be right. But James can more accurately be described as a pluralist - someone who believes the world to be far too complex for any one philosophy to explain everything.

Dewey's philosophy can be described as a version of philosophical naturalism, which regards human experience, intelligence, and communities as ever-evolving mechanisms. Using their experience and intelligence, Dewey believed, human beings can solve problems, including social problems, through inquiry. For Dewey, naturalism led to the idea of a democratic society that allows all members to acquire social intelligence and progress both as individuals and as communities. Dewey held that traditional ideas about knowledge, truth, and values, in which absolutes are assumed, are incompatible with a broadly Darwinian world-view in which individuals and society is progressing. In consequence, he felt that these traditional ideas must be discarded or revised. Indeed, for pragmatists, everything people know and do depend on a historical context and are thus tentative rather than absolute.

Many followers and critics of Dewey believe he advocated elitism and social engineering in his philosophical stance. Others think of him as a kind of romantic humanist. Both tendencies are evident in Dewey's writings, although he aspired to synthesize the two realms.

The pragmatist's tradition was revitalized in the 1980s by American philosopher Richard Rorty, who has faced similar charges of elitism for his belief in the relativism of values and his emphasis on the role of the individual in attaining knowledge. Interest has renewed in the classic pragmatists - Pierce, James, and Dewey - as an alternative to Rorty's interpretation of the tradition.

In an ever-changing world, pragmatism has many benefits. It defends social experimentation as a means of improving society, accepts pluralism, and rejects' dead dogmas. But a philosophy that offers no final answers or absolutes and that appears vague as a result of trying to harmonize opposites may also be unsatisfactory to some.

One of the five branches into which semiotics is usually divided the study of meaning of words, and their relation of designed to the object studied, a semantic is provided for a formal language when an interpretation or model is specified. Nonetheless, the Semantics, the Greek semantikos, 'significant,' the study of the meaning of linguistic signs - that is, words, expressions, and sentences. Scholars of semantics try to one answer such questions as 'What is the meaning of (the word) 'X'? They do this by studying what signs are, as well as how signs possess significance - that is, how they are intended by speakers, how they designate (make reference to things and ideas), and how they are interpreted by hearers. The goal of semantics is to match the meanings of signs - what they stand for - with the process of assigning those meanings.

Semantics is studied from philosophical (pure) and linguistic (descriptive and theoretical) approaches, and an approach known as general semantics. Philosophers look at the behavior that goes with the process of meaning. Linguists study the elements or features of meaning as they are related in a linguistic system. General semanticists concentrate on meaning as influencing what people think and do.

These semantic approaches also have broader application. Anthropologists, through descriptive semantics, study what people categorize as culturally important. Psychologists draw on theoretical semantic studies that attempt to describe the mental process of understanding and to identify how people acquire meaning (as well as sound and structure) in language. Animal behaviorists research how and what other species communicate. Exponents of general semantics examine the different values (or connotations) of signs that supposedly mean the same thing (such as 'the victor at Jena' and 'the loser at Waterloo,' both referring to Napoleon). Also in a general-semantics vein, literary critics have been influenced by studies differentiating literary language from ordinary language and describing how literary metaphors evoke feelings and attitudes.

In the late 19th century Michel Jules Alfred Breal, a French philologist, proposed a 'science of significations' that would investigate how sense is attached to expressions and other signs. In 1910 the British philosopher's Alfred North Whitehead and Bertrand Russell published Principia Mathematica, which strongly influenced the Vienna Circle, a group of philosophers who developed the rigorous philosophical approach known as logical positivism.

One of the leading figures of the Vienna Circle, the German philosopher Rudolf Carnap, made a major contribution to philosophical semantics by developing symbolic logic, a system for analyzing signs and what they designate. In logical positivism, meaning is a relationship between words and things, and its study is empirically based: Because language, ideally, is a direct reflection of reality, signs match things and facts. In symbolic logic, however, mathematical notation is used to state what signs designate and to do so more clearly and precisely than is possible in ordinary language. Symbolic logic is thus itself a language, specifically, a metalanguage (formal technical language) used to talk about an object language (the language that is the object of a given semantic study).

An object language has a speaker (for example, a French woman) using expressions (such as la plume rouge) to designate a meaning (in this case, to indicate a definite pen - a plume - of the Collor red - rouge). The full description of an object language in symbols is called the semiotic of that language. A language's semiotic has the following aspects: (1) a semantic aspect, in which signs (words, expressions, sentences) are given specific designations; (2) a pragmatic aspect, in which the contextual relations between speakers and signs are indicated; and (3) a syntactic aspect, in which formal relations among the elements within signs (for example, among the sounds in a sentence) are indicated.

An interpreted language in symbolic logic is an object language together with rules of meaning that link signs and designations. Each interpreted sign has a truth condition - a condition that must be met in order for the sign to be true. A sign's meaning is what the sign designates when its truth condition is satisfied. For example, the expression or sign 'the moon is a sphere' is understood by someone who knows English; however, although it is understood, it may or may not be true. The expression is true if the thing it is extended to - the moon - is in fact spherical. To determine the sign's truth quality value, one must look at the moon to realize and grasp to its visually perceptive representation of our inseparability with it and the total consciousness of our universe.

The symbolic logic of logical positivist philosophy thus represents an attempt to get at meaning by way of the empirical verifiability of signs - by whether the truth of the sign can be confirmed by observing something in the real world. This attempt at understanding meaning has been only moderately successful. The Austrian-British philosopher Ludwig Wittgenstein rejected it in favour of his 'ordinary language' philosophy, in which he asserted that thought is based on everyday language. Not all signs designate things in the world, he pointed out, nor can all signs be associated with truth values. In his approach to philosophical semantics, the rules of meaning are disclosed in how speech is used.

From ordinary-language philosophy has evolved the current theory of speech-act semantics. The British philosopher J. L. Austin claimed that, by speaking, a person performs an act, or does something (such as state, predict, or warn), and that meaning is found in what an expression does, in the act it performs. The American philosopher John R. Searle extended Austin's ideas, emphasizing the need to relate the functions of signs or expressions to their social context. Searle asserted that speech encompasses at least three kinds of acts: (1) elocutionary acts, in which things are said with a certain sense or reference (as in 'the moon is a sphere'); (2) illocutionary acts, in which such acts as promising or commanding are performed by means of speaking; and (3) perlocutionary acts, in which the speaker, by speaking, does something to someone else (for example, angers, consoles, or persuades someone). The speaker's intentions are conveyed by the illocutionary force that is given to the signs - that is, by the actions implicit in what is said. To be successfully meant, however, the signs must also be appropriate, sincere, consistent with the speaker's general beliefs and conduct, and recognizable as meaningful by the hearer.

What has developed in philosophical semantics, then, is a distinction between truth-based semantics and speech-act semantics. Some critics of speech-act theory believe that it deals primarily with meaning in communication (as opposed to meaning in language) and thus is part of the pragmatic aspect of a language's semiotic - that it relates to signs and to the knowledge of the world shared by speakers and hearers, rather than relating to signs and their designations (semantic aspect) or to formal relations among signs (syntactic aspect). These scholars hold that semantics should be restricted to assigning interpretations to signs alone - independent of a speaker and hearer.

Researchers in descriptive semantics examine what signs mean in particular languages. They aim, for instance, to identify what constitutes nouns or noun phrases and verbs or verb phrases. For some languages, such as English, this is done with subject-predicate analysis. For languages without clear-cut distinctions between nouns, verbs, and prepositions, it is possible to say what the signs mean by analyzing the structure of what are called propositions. In such an analysis, a sign is seen as an operator that combines with one or more arguments (also signs), often nominal argument (noun phrases) or, relates nominal arguments to other elements in the expression (such as prepositional phrases or adverbial phrases). For example, in the expression 'Bill gives Mary the book, ''gives' is an operator that relates the arguments 'Bill, ''Mary,' and 'the book.'

Whether using subject-predicate analysis or propositional analysis, descriptive semanticists establish expression classes (classes of items that can substitute for one another within a sign) and classes of items within the conventional parts of speech (such as nouns and verbs). The resulting classes are thus defined in terms of syntax, and they also have semantic roles; that is, the items in these classes perform specific grammatical functions, and in so doing they establish meaning by predicating, referring, making distinctions among entities, relations, or actions. For example, 'kiss' belongs to an expression class with other items such as 'hit' and 'see,' as well as to the conventional part of speech 'verb,' in which it is part of a subclass of operators requiring two arguments (an actor and a receiver). In 'Mary kissed John,' the syntactic role of 'kiss' is to relate two nominal arguments ('Mary' and 'John'), whereas its semantic role is to identify a type of action. Unfortunately for descriptive semantics, however, it is not always possible to find a one-to-one correlation of syntactic classes with semantic roles. For instance, 'John' has the same semantic role - to identify a person - in the following two sentences: 'John is easy to please' and 'John is eager to please.' The syntactic role of 'John' in the two sentences, however, is different: In the first, 'John' is the receiver of an action; in the second, 'John' is the actor.

Linguistic semantics is also used by anthropologists called ethnoscientists to conduct formal semantic analysis (componential analysis) to determine how expressed signs - usually single words as vocabulary items called lexemes - in a language are related to the perceptions and thoughts of the people who speak the language. Componential analysis tests the idea that linguistic categories influence or determine how people view the world; this idea is called the Whorf hypothesis after the American anthropological linguist Benjamin Lee Whorf, who proposed it. In componential analysis, lexemes that have a common range of meaning constitute a semantic domain. Such a domain is characterized by the distinctive semantic features (components) that differentiate individual lexemes in the domain from one another, and also by features shared by all the lexemes in the domain. Such componential analysis points out, for example, that in the domain 'seat' in English, the lexemes 'chair, ''sofa, ''loveseat,' and 'bench' can be distinguished from one another according too many people are accommodated and whether a back support is included. At the same time all these lexemes share the common component, or feature, of meaning 'something on which to sit.'

Linguists pursuing such componential analysis hope to identify a universal set of such semantic features, from which are drawn the different sets of features that characterize different languages. This idea of universal semantic features has been applied to the analysis of systems of myth and kinship in various cultures by the French anthropologist Claude Lévi-Strauss. He showed that people organize their societies and interpret their place in these societies in ways that, despite apparent differences, have remarkable underlying similarities.

Linguists concerned with theoretical semantics are looking for a general theory of meaning in language. To such linguists, known as transformational-generative grammarians, meaning is part of the linguistic knowledge or competence that all humans possess. A generative grammar as a model of linguistic competence has a phonological (sound-system), a syntactic, and a semantic component. The semantic component, as part of a generative theory of meaning, is envisioned as a system of rules that govern how interpretable signs are interpreted and determine that other signs (such as 'Colourless green ideas sleep furiously'), although grammatical expressions, are meaningless - semantically blocked. The rules must also account for how a sentence such as 'They passed the port at midnight' can have at least two interpretations.

Generative semantics grew out of proposals to explain a speaker's ability to produce and understand new expressions where grammar or syntax fails. Its goal is to explain why and how, for example, a person understands at first hearing that the sentence 'Colourless green ideas sleep furiously' has no meaning, even though it follows the rules of English grammar; or how, in hearing a sentence with two possible interpretations (such as 'They passed the port at midnight'), one decides which meaning applies.

In generative semantics, the idea developed that all information needed to semantically interpret a sign (usually a sentence) is contained in the sentence's underlying grammatical or syntactic deep structure. The deep structure of a sentence involves lexemes (understood as words or vocabulary items composed of bundles of semantic features selected from the proposed universal set of semantic features). On the sentence's surface (that is, when it is spoken) these lexemes will appear as nouns, verbs, adjectives, and other parts of speech - that is, as vocabulary items. When the sentence is formulated by the speaker, semantic roles (such as subject, objects, predicate) are assigned to the lexemes; The listener hears the spoken sentence and interprets the semantic features that are meant.

Whether deep structure and semantic interpretation are distinct from one, another is a matter of controversy. Most generative linguists agree, however, that a grammar should generate the set of semantically well-formed expressions that are possible in a given language, and that the grammar should associate a semantic interpretation with each expression.

Another subject of debate is whether semantic interpretation should be understood as syntactically based (that is, coming from a sentence's deep structure); or whether it should be seen as semantically based. According to Noam Chomsky, an American scholar who is particularly influential in this field, it is possible - in a syntactically based theory - for surface structure and deep structure jointly to determine the semantic interpretation of an expression.

The focus of general semantics is how people evaluate words and how that evaluation influences their behavior. Begun by the Polish American linguist Alfred Korzybski and long associated with the American semanticist and politician S. I. Hayakawa, general semantics has been used in efforts to make people aware of dangers inherent in treating words as more than symbols. It has been extremely popular with writers who use language to influence people's ideas. In their work, these writers use general-semantics guidelines for avoiding loose generalizations, rigid attitudes, inappropriate finality, and imprecision. Some philosophers and linguists, however, have criticized general semantics as lacking scientific rigour, and the approach has declined in popularity.

Positivism, system of philosophy based on experience and empirical knowledge of natural phenomena, in which metaphysics and theology are regarded as inadequate and imperfect systems of knowledge. The doctrine was first called positivism by the 19th-century French mathematician and philosopher Auguste Comte (1798-1857), but some of the positivist concepts may be traced to the British philosopher David Hume, the French philosopher Duc de Saint-Simon, and the German philosopher Immanuel Kant.

Comte chose the word positivism on the ground that it indicated the 'reality' and 'constructive tendency' that he claimed for the theoretical aspect of the doctrine. He was, in the main, interested in a reorganization of social life for the good of humanity through scientific knowledge, and thus mastering of natural forces. The two primary components of positivism, the philosophy and the polity (or programs of individual and social conduct), were later welded by Comte into a whole under the conception of a religion, in which humanity was the object of worship. A number of Comte's disciples refused, however, to accept this religious development of his philosophy, because it seemed to contradict the original positivist philosophy. Many of Comte's doctrines were later adapted and developed by the British social philosophers John Stuart Mill and Herbert Spencer and by the Austrian philosopher and physicist Ernst Mach.

The principle named But rejected by the English economist and philosopher John Maynard Keyes (1883-1946) whereby if there is no known reason for asserting one than another out of several alternatives, then relative to our knowledge they have an equal probability. Without restriction the principle leads to contradiction, for example, if we know nothing about the nationality of a person, we might argue that the probability is equal that she comes from England or France, and equal that she comes from Scotland or France. But from the first two assertions the probability that she belongs to Britain must be at least double the probability that belongs to France.

A paradox arises when a set class of apparent incontrovertible premises gives unacceptable or contradictory conclusions. To solve a paradox will involve showing either that there is a hidden flaw in the premises, or that the reasoning is erroneous, or that the apparently unacceptable conclusion can, in fact, be tolerated. Paradoxes are therefore important in philosophy, for until one is solved it shows that there is something about our reasoning and our concepts that we do not understand.

By comparison, the moral philosopher and epistemologist Bernard Bolzano (1781-1848) argues, though, that there is something else, an infinity that doe not have this whatever you need it to be elasticity. In fact a truly infinite quantity (for example, the length of a straight ligne unbounded in either direction, meaning : The magnitude of the spatial entity containing all the points determined solely by their abstractly conceivable relation to two fixed points) does not by any means need to be variable, and in adduced example it is in fact not variable. Conversely, it is quite possible for a quantity merely capable of being taken greater than we have already taken it, and of becoming larger than any preassigned (finite) quantity, nevertheless it is to mean, in that of all times is merely finite, which holds in particular of every numerical quantity 1, 2, 3, 4, 5.

In other words, for Bolzano there could be a true infinity that was not a variable something that was only bigger than anything you might specify. Such a true infinity was the result of joining two points together and extending that ligne in both directions without stopping. And what is more, he could separate off the demands of calculus, using a finite quality without ever bothering with the slippery potential infinity. Here was both a deeper understanding of the nature of infinity and the basis on which are built in his safe infinity free calculus.

This use of the inexhaustible follows on directly from most Bolzanos' criticism of the way that ? we used as à variable something that would be bigger than anything you could specify, but never quite reached the true, absolute infinity. In Paradoxes of the Infinity Bolzano points out that is possible for a quantity merely capable of becoming larger than any other one pre-assigned (finite) quantity, nevertheless to remain at all times merely finite.

Bolzano intended this as à criticism of the way infinity was treated, but Professor Jacquette sees it instead of a way of masking use of practical applications like calculus without the need for weaker words about infinity.

By replacing ? with ¤ we do away with one of the most common requirements for infinity, but is there anything left that map out to the real world ? Can we confine infinity to that pure mathematical other world, where anything, however unreal, can be constructed, and forget about it elsewhere ? Surprisingly, this seems to have been the view, at least at one point in time, even of the German mathematician and founder of set-theory Georg Cantor (1845-1918), himself, whose comment in 1883, that only the finite numbers are real.

Keeping within the lines of reason, both these Cambridge mathematician and philosopher Frank Plumpton Ramsey (1903-30) and the Italian mathematician G. Peano (1858-1932) have been to distinguish logical paradoxes and that depend upon the notion of reference or truth (semantic notions), such are the postulates justifying mathematical induction. It ensures that a numerical series is closed, in the sense that nothing but zero and its successors can be numbers. In that any series satisfying a set of axioms can be conceived as the sequence of natural numbers. Candidates from set theory include the Zermelo numbers, where the empty set is zero, and the successor of each number is its unit set, and the von Neuman numbers, where each number is the set of all smaller numbers. A similar and equally fundamental complementarity exists in the relation between zero and infinity. Although the fullness of infinity is logically antithetical to the emptiness of zero, infinity can be obtained from zero with a simple mathematical operation. The division of many numbers by zero is infinity, while the multiplication of any number by zero is zero.

With the set theory developed by the German mathematician and logician Georg Cantor. From 1878 to 1807, Cantor created a theory of abstract sets of entities that eventually became a mathematical discipline. A set, as he defined it, is a collection of definite and distinguished objets in thought or perception conceived as à whole.

Cantor attempted to prove that the process of counting and the definition of integers could be placed on a solid mathematical foundation. His method was to repeatedly place the elements in one set into one-to-one correspondence with those in another. In the case of integers, Cantor showed that each integer (1, 2, 3, . . . n) could be paired with an even integers (2, 4, 6, . . . n), and, therefore, that the set of all integers was equal to the set of all even numbers.

Amazingly, Cantor discovered that some infinite sets were large than others and that infinite sets formed a hierarchy of greater infinities. After this failed attempt to save the classical view of logical foundations and internal consistency of mathematical systems, it soon became obvious that a major crack had appeared in the seemingly sold foundations of number and mathematics. Meanwhile, an impressive number of mathematicians began to see that everything from functional analysis to the theory of real numbers depended on the problematic character of number itself.

While, in the theory of probability Ramsey was the first to show how a personalized theory could be developed, based on precise behavioural notions of preference and expectation. In the philosophy of language, Ramsey was one of the first thinkers to accept a redundancy theory of truth, which hr combined with radical views of the function of man y kinds of propositions. Neither generalizations nor causal propositions, nor those treating probability or ethics, describe facts, but each has a different specific function in our intellectual economy.

Ramsey advocates that of a sentence generated by taking all the sentence affirmed in a scientific theory that use some term, e.g., quark. Replacing the term by a variable, and existentially quantifying into the result. Instead of saying quarks have such-and-such properties, Ramsey postdated that the sentence as saying that there is something that has those properties. If the process is repeated, the sentence gives the topic-neutral structure of the theory, but removes any implications that we know what the term so treated denote. It leaves open the possibility of identifying the theoretical item with whatever it is that best fits the description provided. Nonetheless, it was pointed out by the Cambridge mathematician Newman that if the process is carried out for all except the logical bones of the theory, then by the Löwenheim-Skolem theorem, the result will be interpretable in any domain of sufficient cardinality, and the content of the theory may reasonably be felt to have been lost.

It seems, that the most taken of paradoxes in the foundations of set theory as discovered by Russell in 1901. Some classes have themselves as members: The class of all abstract objects, for example, is an abstract object, whereby, others do not : The class of donkeys is not itself a donkey. Now consider the class of all classes that are not members of themselves, is this class a member of itself, that, if it is, then it is not, and if it is not, then it is.

The paradox is structurally similar to easier examples, such as the paradox of the barber. Such one like a village having a barber in it, who shaves all and only the people who do not have in themselves. Who shaves the barber ? If he shaves himself, then he does not, but if he does not shave himself, then he does not. The paradox is actually just a proof that there is no such barber or in other words, that the condition is inconsistent. All the same, it is no to easy to say why there is no such class as the one Russell defines. It seems that there must be some restriction on the kind of definition that are allowed to define classes and the difficulty that of finding a well-motivated principle behind any such restriction.

The French mathematician and philosopher Henri Jules Poincaré (1854-1912) believed that paradoxes like those of Russell and the barber were due to such as the impredicative definitions, and therefore proposed banning them. But, it tuns out that classical mathematics required such definitions at too many points for the ban to be easily absolved. Having, in turn, as forwarded by Poincaré and Russell, was that in order to solve the logical and semantic paradoxes it would have to ban any collection (set) containing members that can only be defined by means of the collection taken as à whole. It is, effectively by all occurring principles into which have an adopting vicious regress, as to mark the definition for which involves no such failure. There is frequently room for dispute about whether regresses are benign or vicious, since the issue will hinge on whether it is necessary to reapply the procedure. The cosmological argument is an attempt to find a stopping point for what is otherwise seen as being an infinite regress, and, to ban of the predicative definitions.

The investigation of questions that arise from reflection upon sciences and scientific inquiry, are such as called of a philosophy of science. Such questions include, what distinctions in the methods of science ? There is a clear demarcation between scenes and other disciplines, and how do we place such enquires as history, economics or sociology ? And scientific theories probable or more in the nature of provisional conjecture ? Can the be verified or falsified ? What distinguished good from bad explanations ? Might there be one unified since, embracing all the special science ? For much of the 20th century there questions were pursued in a highly abstract and logical framework it being supposed that as general logic of scientific discovery that a general logic of scientific discovery a justification might be found. However, many now take interests in a more historical, contextual and sometimes sociological approach, in which the methods and successes of a science at a particular time are regarded less in terms of universal logical principles and procedure, and more in terms of their availability to methods and paradigms as well as the social context.

In addition, to general questions of methodology, there are specific problems within particular sciences, giving subjects as biology, mathematics and physics.

The intuitive certainty that sparks aflame the dialectic awarenesses for its immediate concerns are either of the truth or by some other in an object of apprehensions, such as à concept. Awareness as such, has to its amounting quality value the place where philosophical understanding of the source of our knowledge are, however, in covering the sensible apprehension of things and pure intuition it is that which stricture sensation into the experience of things accent of its direction that orchestrates the celestial overture into measures in space and time.

The notion that determines how something is seen or evaluated of the status of law and morality especially associated with St. Thomas Aquinas and the subsequent scholastic tradition. More widely, any attempt to cement the moral and legal order together with the nature of the cosmos or how the nature of human beings, for which sense it is also found in some Protestant writers, and arguably derivative from a Platonic view of ethics, and is implicit in ancient Stoicism. Law stands above and apart from the activities of human lawmaker, it constitutes an objective set of principles that can be seen true by natural light or reason, and (in religion versions of the theory) that express Gods' will for creation. Non-religious versions of the theory substitute objective conditions for human flourishing as the source of constraints upon permissible actions and social arrangements. Within the natural law tradition, different views have been held about the relationship between the rule of law about God s will, for instance the Dutch philosopher Hugo Grothius (1583-1645), similarly takes upon the view that the content of natural law is independent of any will, including that of God, while the German theorist and historian Samuel von Pufendorf (1632-94) takes the opposite view, thereby facing the problem of one horn of the Euthyphro dilemma, that simply states, that its dilemma arises from whatever the source of authority is supposed to be, for in which do we care about the general good because it is good, or do we just call good things that we care about. Wherefore, by facing the problem that may be to assume of a strong form, in which it is claimed that various facts entail values, or a weaker form, from which it confines itself to holding that reason by itself is capable of discerning moral requirements that are supped of binding to all human bings regardless of their desires

Although the morality of people send the ethical amount from which the same thing, is that there is a usage that restricts morality to systems such as that of the German philosopher and founder of ethical philosophy Immanuel Kant (1724-1804), based on notions such as duty, obligation, and principles of conduct, reserving ethics for more than the Aristotelian approach to practical reasoning based on the notion of a virtue, and generally avoiding the separation of moral considerations from other practical considerations. The scholarly issues are complex, with some writers seeing Kant as more Aristotelian and Aristotle as, ore involved in a separate sphere of responsibility and duty, than the simple contrast suggests. Some theorists see the subject in terms of a number of laws (as in the Ten Commandments). The status of these laws may be test they are the edicts of a divine lawmaker, or that they are truths of reason, knowable deductively. Other approaches to ethics (e.g., eudaimonism, situation ethics, virtue ethics) eschew general principles as much as possible, frequently disguising the great complexity of practical reasoning. For Kantian notion of the moral law is a binding requirement of the categorical imperative, and to understand whether they are equivalent at some deep level. Kants own applications of the notion are not always convincing, as for one cause of confusion in relating Kants ethics to theories such additional expressivism is that it is easy, but mistaken, to suppose that the categorical nature of the imperative means that it cannot be the expression of sentiment, but must derive from something unconditional or necessary such as the voice of reason.

For which ever reason, the mortal being makes of its presence to the future of weighing of that which one must do, or that which can be required of one. The term carries implications of that which is owed (due) to other people, or perhaps in onself. Universal duties would be owed to persons (or sentient beings) as such, whereas special duty in virtue of specific relations, such as being the child of someone, or having made someone a promise. Duty or obligation is the primary concept of deontological approaches to ethics, but is constructed in other systems out of other notions. In the system of Kant, a perfect duty is one that must be performed whatever the circumstances : Imperfect duties may have to give way to the more stringent ones. In another way, perfect duties are those that are correlative with the right to others, imperfect duties are not. Problems with the concept include the ways in which due needs to be specified (a frequent criticism of Kant is that his notion of duty is too abstract). The concept may also suggest of a regimented view of ethical life in which we are all forced conscripts in a kind of moral army, and may encourage an individualistic and antagonistic view of social relations.

The most generally accepted account of externalism and/or internalism, that this distinction is that a theory of justification is Internalist if only if it requiem that all of the factors needed for a belief to be epistemologically justified for a given person be cognitively accessible to that person, internal to cognitive perceptivity, and externalist, if it allows that at least some of the justifying factors need not be thus accessible, so that thy can be external to the believers cognitive perceptive, beyond any such given relations. However, epistemologists often use the distinction between Internalist and externalist theories of epistemic justification without offering any very explicit explication.

The externalist/Internalist distinction has been mainly applied to theories of epistemic justification : It has also been applied in a closely related way to accounts of knowledge and in a rather different way to accounts of belief and thought contents.

The Internalist requirement of cognitive accessibility can be interpreted in at least two ways : A strong version of internalism would require that the believe actually be aware of the justifying factor in order to be justified : While a weaker version would require only that he be capable of becoming aware of them by focussing his attentions appropriately, but without the need for any change of position, new information, etc. Though the phrase cognitively accessible suggests the weak interpretation, the main intuitive motivation for internalism, viz. the idea that epistemic justification requires that the believe actually have in his cognitive possession a reason for thinking that the belief is true, and would require the strong interpretation.

Perhaps, the clearest example of an Internalist position would be a Foundationalist view according to which foundational beliefs pertain to immediately experienced states of mind and other beliefs are justified by standing in cognitively accessible logical or inferential relations to such foundational beliefs. Such a view could count as either a strong or a weak version of internalism, depending on whether actual awareness of the justifying elements or only the capacity to become aware of them is required. Similarly, a coherent view could also be Internalist, if both the beliefs or other states with which a justification belief is required to cohere and the coherence relations themselves are reflectively accessible.

It should be carefully noticed that when internalism is construed in this way, it is neither necessary nor sufficient by itself for internalism that the justifying factors literally be internal mental states of the person in question. Not necessary, necessary, because on at least some views, e.g., a direct realist view of perception, something other than a mental state of the believe can be cognitively accessible : Not sufficient, because there are views according to which at least some mental states need not be actual (strong version) or even possible (weak version) objects of cognitive awareness. Also, on this way of drawing the distinction, a hybrid view, according to which some of the factors required for justification must be cognitively accessible while others need not and in general will not be, would count as an externalist view. Obviously too, a view that was externalist in relation to a strong version of internalism (by not requiring that the believe actually be aware of all justifiable factors) could still be Internalist in relation to a weak version (by requiring that he at least be capable of becoming aware of them).

The most prominent recent externalist views have been versions of reliabilism, whose requirements for justification is roughly that the belief be produced in a way or via a process that makes of objectively likely that the belief is true. What makes such a view externalist is the absence of any requirement that the person for whom the belief is justified have any sort of cognitive access to the relations of reliability in question. Lacking such access, such a person will in general have no reason for thinking that the belief is true or likely to be true, but will, on such an account, nonetheless be epistemically justified in according it. Thus such a view arguably marks a major break from the modern epistemological tradition, stemming from Descartes, which identifies epistemic justification with having a reason, perhaps even a conclusive reason for thinking that the belief is true. An epistemologist working within this tradition is likely to feel that the externalist, than offering a competing account of the same concept of epistemic justification with which the traditional epistemologist is concerned, has simply changed the subject.

The main objection to externalism rests on the intuitive certainty that the basic requirement for epistemic justification is that the acceptance of the belief in question be rational or responsible in relation to the cognitive goal of truth, which seems to require in turn that the believe actually be dialectally aware of a reason for thinking that the belief is true (or, at the very least, that such a reason be available to him). Since the satisfaction of an externalist condition is neither necessary nor sufficient for the existence of such a cognitively accessible reason, it is argued, externalism is mistaken as an account of epistemic justification. This general point has been elaborated by appeal to two sorts of putative intuitive counter-examples to externalism. The first of these challenges the necessity of belief which seem intuitively to be justified, but for which the externalist conditions are not satisfied. The standard examples in this sort are cases where beliefs are produced in some very nonstandard way, e.g., by a Cartesian demon, but nonetheless, in such a way that the subjective experience of the believe is indistinguishable from that of someone whose beliefs are produced more normally. The intuitive claim is that the believe in such a case is nonetheless epistemically justified, as much so as one whose belief is produced in a more normal way, and hence that externalist account of justification must be mistaken.

Perhaps the most striking reply to this sort of counter-example, on behalf of a cognitive process is to be assessed in normal possible worlds, i.e., in possible worlds that are actually the way our world is common-seismically believed to be, than in the world which contains the belief being judged. Since the cognitive processes employed in the Cartesian demon cases are, for which we may assume, reliable when assessed in this way, the reliability can agree that such beliefs are justified. The obvious, to a considerable degree of bringing out the issue of whether it is or not an adequate rationale for this construal of Reliabilism, so that the reply is not merely a notional presupposition guised as having representation.

The correlative way of elaborating on the general objection to justificatory externalism challenges the sufficiency of the various externalist conditions by citing cases where those conditions are satisfied, but where the believers in question seem intuitively not to be justified. In this context, the most widely discussed examples have to do with possible occult cognitive capacities, like clairvoyance. Considering the point in application once, again, to Reliabilism, the claim is that to think that he has such a cognitive power, and, perhaps, even good reasons to the contrary, is not rational or responsible and therefore not epistemically justified in accepting the belief that result from his clairvoyance, despite the fact that the Reliabilist condition is satisfied.

One sort of response to this latter sorts of objection is to bite the bullet and insist that such believers are in fact justified, dismissing the seeming intuitions to the contrary as latent Internalist prejudice. A more widely adopted response attempts to impose additional conditions, usually of a roughly internalized sort, which will rule out the offending example, while stopping far of a full internalism. But, while there is little doubt that such modified versions of externalism can handle particular cases, as well enough to avoid clear intuitive implausibility, the usually problematic cases that they cannot handle, and also whether there is and clear motivation for the additional requirements other than the general Internalist view of justification that externalist are committed to reject.

A view in this same general vein, one that might be described as a hybrid of internalism and externalism holds that epistemic justification requires that there is a justificatory factor that is cognitively accessible to the believe in question (though it need not be actually grasped), thus ruling out, e.g., a pure Reliabilism. At the same time, however, though it must be objectively true that beliefs for which such a factor is available are likely to be true, in addition, the fact need not be in any way grasped or cognitively accessible to the believe. In effect, of the premises needed to argue that a particular belief is likely to be true, one must be accessible in a way that would satisfy at least weakly internalized. The Internalist will respond that this hybrid view is of no help at all in meeting the objection and has no belief nor is it held in the rational, responsible way that justification intuitively seems to require, for the believe in question, lacking one crucial premise, still has no reason at all for thinking that his belief is likely to be true.

An alternative to giving an externalist account of epistemic justification, one which may be more defensible while still accommodating many of the same motivating concerns, is to give an externalist account of knowledge directly, without relying on an intermediate account of justification. Such a view will obviously have to reject the justified true belief account of knowledge, holding instead that knowledge is true belief which satisfies the chosen externalist condition, e.g., a result of a reliable process (and perhaps, further conditions as well). This makes it possible for such a view to retain Internalist account of epistemic justification, though the centrality of that concept to epistemology would obviously be seriously diminished.

Such an externalist account of knowledge can accommodate the commonsense conviction that animals, young children, and unsophisticated adults posses knowledge, though not the weaker conviction (if such a conviction does exists) that such individuals are epistemically justified in their beliefs. It is also at least less vulnerable to Internalist counter-examples of the sort discussed, since the intuitions involved there pertain more clearly to justification than to knowledge. What is uncertain is what ultimate philosophical significance the resulting conception of knowledge is supposed to have. In particular, does it have any serious bearing on traditional epistemological problems and on the deepest and most troubling versions of scepticism, which seems in fact to be primarily concerned with justification, the an knowledge ?`

A rather different use of the terms internalism and externalism has to do with the issue of how the content of beliefs and thoughts is determined : According to an Internalist view of content, the content of such intention states depends only on the non-relational, internal properties of the individuals mind or grain, and not at all on his physical and social environment : While according to an externalist view, content is significantly affected by such external factors and suggests a view that appears of both internal and external elements are standardly classified as an external view.

As with justification and knowledge, the traditional view of content has been strongly internalized in character. The main argument for externalism derives from the philosophy of language, more specifically from the various phenomena pertaining to natural kind terms, indexicals, etc. that motivate the views that have come to be known as direct reference theories. Such phenomena seem at least to show that the belief or thought content that can be properly attributed to a person is dependant on facts about his environment, e.g., whether he is on Earth or Twin Earth, what is fact pointing at, the classificatory criteria employed by expects in his social group, etc. - not just on what is going on internally in his mind or brain.

An objection to externalist account of content is that they seem unable to do justice to our ability to know the content of our beliefs or thought from the inside, simply by reflection. If content is depend on external factors pertaining to the environment, then knowledge of content should depend on knowledge of these factors - which will not in general be available to the person whose belief or thought is in question.

The adoption of an externalized account of mental content would seem to support an externalist account of justification, by way that if part or all of the content of a belief inaccessible to the believe, then both the justifying status of other beliefs in relation to that content and the status of that content justifying the beliefs will be similarly inaccessible, thus contravening the Internalist requirement for justification. An Internalist must insist that there are no justifiable relations of these sorts, that our internally associable content can either be justified or justly anything else : But such a response appears lame unless it is coupled with an attempt to show that the externalist account of content is mistaken.

A great deal of philosophical effort has been lavished on the attempt to naturalize content, i.e. to explain in non-semantic, Non-intentional terms what it is for something to be representational (have content) and what it is for something to have some particular content rather than some other. There appear to be only four types of theory that have been proposed: Theories that ground representation in (1) similarity, (2) conversance, (3) functional role, (4) teleology.

Similarly, theories hold that 'r' represents 'x' in virtue of being similar to 'x'. This has seemed hopeless to most as a theory of mental representation because it appears to require that things in the brain must share properties with the things they represent: To represent a cat as furry appears to require something furry in the brain. Perhaps, a notion of similarity that is naturalistic and does not involve property sharing can be worked out, but it is not obvious how.

Covariance theories hold that 'r's' represent 'x' is grounded in the fact that 'r's', occasion canaries with that of 'x'. This is most compelling he n one thinks about detection systems, the firing a neural structures in the visual system is said to represent vertical orientations, if its firing varies with the occurrence of vertical lines in the visual field of perceptivity.

Functional role theories hold that 'r's' represent 'x' is grounded in the functional role 'r' has in the representing system, i.e., on the relations imposed by specific cognitive processes imposed by specific cognitive processes between 'r' and other representations in the system's repertoire. Functional role theories take their cue from such common-sense ideas as that people cannot believer that cats are furry if they did not know that cats are animals or that fur is like hair.

Teleological theories hold that 'r' represent 'x' if it is 'r's' function to indicate, i.e., covary with 'x'. Teleological theories differ depending on the theory of functions they import. Perhaps the most important distinction is that between historical theories of functions. Historical theories individuated functional states (hence contents) in a way that is sensitive to the historical development of the state, i.e., to factors such as the way the state was 'learned', or the way it evolved. An historical theory might hold that the function of 'r' is to indicate 'x' only if the capacity to token 'r' was developed (selected, learned) because it indicates 'x'. Thus, a state physically indistinguishable from 'r's' historical origins would not represent 'x' according to historical theories.

Theories of representational content may be classified according to whether they are atomistic or holistic and according to whether they are externalistic or internalistic, whereby, emphasizing the priority of a whole over its parts. Furthermore, in the philosophy of language, this becomes the claim that the meaning of an individual word or sentence can only be understood in terms of its relation to an indefinitely larger body of language, such as a whole theory, or even a whole language or form of life. In the philosophy of mind a mental state similarly may be identified only in terms of its relations with others. Moderate holism may allow the other things besides these relationships also count; extreme holism would hold that a network of relationships is all that we have. A holistic view of science holds that experience only confirms or disconfirms large bodies of doctrine, impinging at the edges, and leaving some leeway over the adjustment that it requires.

Once, again, in the philosophy of mind and language, the view that what is thought, or said, or experienced, is essentially dependent on aspects of the world external to the mind of the subject. The view goes beyond holding that such mental states are typically caused by external factors, to insist that they could not have existed as they now do without the subject being embedded in an external world of a certain kind. It is these external relations that make up the essence or identify of the mental state. Externalism is thus opposed to the Cartesian separation of the mental from the physical, since that holds that the mental could in principle exist as it does even if there were no external world at all. Various external factors have been advanced as ones on which mental content depends, including the usage of experts, the linguistic, norms of the community. And the general causal relationships of the subject. In the theory of knowledge, externalism is the view that a person might know something by being suitably situated with respect to it, without that relationship being in any sense within his purview. The person might, for example, be very reliable in some respect without believing that he is. The view allows that you can know without being justified in believing that you know.

However, atomistic theories take a representation's content to be something that can be specified independent entity of that representation' s relations to other representations. What the American philosopher of mind, Jerry Alan Fodor (1935-) calls the crude causal theory, for example, takes a representation to be a
cow
- a menial representation with the same content as the word 'cow' - if its tokens are caused by instantiations of the property of being-a-cow, and this is a condition that places no explicit constraints on how
cow
's must or might relate to other representations. Holistic theories contrasted with atomistic theories in taking the relations a representation bears to others to be essential to its content. According to functional role theories, a representation is a
cow
if it behaves like a
cow
should behave in inference.

Internalist theories take the content of a representation to be a matter determined by factors internal to the system that uses it. Thus, what Block (1986) calls 'short-armed' functional role theories are Internalist. Externalist theories take the content of a representation to be determined, in part at least, by factors external to the system that uses it. Covariance theories, as well as telelogical theories that invoke an historical theory of functions, take content to be determined by 'external' factors. Crossing the atomist-holistic distinction with the Internalist-externalist distinction.

Externalist theories (sometimes called non-individualistic theories) have the consequence that molecule for molecule are coincide with the identical cognitive systems might yet harbour representations with different contents. This has given rise to a controversy concerning 'narrow' content. If we assume some form of externalist theory is correct, then content is, in the first instance 'wide' content, i.e., determined in part by factors external to the representing system. On the other hand, it seems clear that, on plausible assumptions about how to individuate psychological capacities, internally equivalent systems must have the same psychological capacities. Hence, it would appear that wide content cannot be relevant to characterizing psychological equivalence. Since cognitive science generally assumes that content is relevant to characterizing psychological equivalence, philosophers attracted to externalist theories of content have sometimes attempted to introduce 'narrow' content, i.e., an aspect or kind of content that is equivalent internally equivalent systems. The simplest such theory is Fodor's idea (1987) that narrow content is a function from contents (i.e., from whatever the external factors are) to wide contents.

All the same, what a person expresses by a sentence is often a function of the environment in which he or she is placed. For example, the disease I refer to by the term like 'arthritis', or the kind of tree I refer to as a 'Maple' will be defined by criteria of which I know next to nothing. This raises the possibility of imagining two persons in rather different environments, but in which everything appears the same to each of them. The wide content of their thoughts and sayings will be different if the situation surrounding them is appropriately different: 'situation' may include the actual objects they perceive or the chemical or physical kinds of object in the world they inhabit, or the history of their words, or the decisions of authorities on what counts as an example, of one of the terms they use. The narrow content is that part of their thought which remains identical, through their identity of the way things appear, regardless of these differences of surroundings. Partisans of wide content may doubt whether any content in this sense narrow, partisans of narrow content believer that it is the fundamental notion, with wide content being explicable in terms of narrow content plus context.

Even so, the distinction between facts and values has outgrown its name: it applies not only to matters of fact vs, matters of value, but also to statements that something is, vs. statements that something ought to be. Roughly, factual statements - 'is statements' in the relevant sense - represent some state of affairs as obtaining, whereas normative statements - evaluative, and deontic ones - attribute goodness to something, or ascribe, to an agent, an obligation to act. Neither distinction is merely linguistic. Specifying a book's monetary value is making a factual statement, though it attributes a kind of value. 'That is a good book' expresses a value judgement though the term 'value' is absent (nor would 'valuable' be synonymous with 'good'). Similarly, 'we are morally obligated to fight' superficially expresses a statement, and 'By all indications it ough to rain' makes a kind of ought-claim; but the former is an ought-statement, the latter an (epistemic) is-statement.

Theoretical difficulties also beset the distinction. Some have absorbed values into facts holding that all value is instrumental, roughly, to have value is to contribute - in a factual analyzable way - to something further which is (say) deemed desirable. Others have suffused facts with values, arguing that facts (and observations) are 'theory-impregnated' and contending that values are inescapable to theoretical choice. But while some philosophers doubt that fact/value distinctions can be sustained, there persists a sense of a deep difference between evaluating, and attributing an obligation and, on the other hand, saying how the world is.

Fact/value distinctions, may be defended by appeal to the notion of intrinsic value, value a thing has in itself and thus independently of its consequences. Roughly, a value statement (proper) is an ascription of intrinsic value, one to the effect that a thing is to some degree good in itself. This leaves open whether ought-statements are implicitly value statements, but even if they imply that something has intrinsic value - e.g., moral value - they can be independently characterized, say by appeal to rules that provide (justifying) reasons for action. One might also ground the fact value distinction in the attributional (or even motivational) component apparently implied by the making of valuational or deontic judgements: Thus, 'it is a good book, but that is no reason for a positive attribute towards it' and 'you ought to do it, but there is no reason to' seem inadmissible, whereas, substituting, 'an expensive book' and 'you will do it' yields permissible judgements. One might also argue that factual judgements are the kind which are in principle appraisable scientifically, and thereby anchor the distinction on the factual side. This ligne is plausible, but there is controversy over whether scientific procedures are 'value-free' in the required way.

Philosophers differ regarding the sense, if any, in which epistemology is normative (roughly, valuational). But what precisely is at stake in this controversy is no clearly than the problematic fact/value distinction itself. Must epistemologists as such make judgements of value or epistemic responsibility? If epistemology is naturalizable, then even epistemic principles simply articulate under what conditions - say, appropriate perceptual stimulations - a belief is justified, or constitutes knowledge. Its standards of justification, then would be like standards of, e.g., resilience for bridges. It is not obvious, however, that there appropriate standards can be established without independent judgements that, say, a certain kind of evidence is good enough for justified belief (or knowledge). The most plausible view may be that justification is like intrinsic goodness, though it supervenes on natural properties, it cannot be analysed wholly in factual statements.

Thus far, belief has been depicted as being all-or-nothing, however, as a resulting causality for which we have grounds for thinking it true, and, all the same, its acceptance is governed by epistemic norms, and, least of mention, it is partially subject to voluntary control and has functional affinities to belief. Still, the notion of acceptance, like that of degrees of belief, merely extends the standard picture, and does not replace it.

Traditionally, belief has been of epistemological interest in its propositional guise: 'S' believes that 'p', where 'p' is a reposition towards which an agent, 'S' exhibits an attitude of acceptance. Not all belief is of this sort. If I trust you to say, I believer you. And someone may believer in Mr. Radek, or in a free-market economy, or in God. It is sometimes supposed that all belief is 'reducible' to propositional belief, belief-that. Thus, my believing you might be thought a matter of my believing, is, perhaps, that what you say is true, and your belief in free markets or God, is a matter of your believing that free-market economies are desirable or that God exists.

Some philosophers have followed St., Thomas Aquinas (1225-74), in supposing that to believer in God is simply to believer that certain truths hold while others argue that belief-in is a distinctive attitude, on that includes essentially an element of trust. More commonly, belief-in has been taken to involve a combination of propositional belief together with some further attitude.

The moral philosopher Richard Price (1723-91) defends the claim that there are different sorts of belief-in, some, but not all reducible to beliefs-that. If you believer in God, you believer that God exists, that God is good, you believer that God is good, etc. But according to Price, your belief involves, in addition, a certain complex pro-attitude toward its object. Even so, belief-in outruns the evidence for the corresponding belief-that. Does this diminish its rationality? If belief-in presupposes believes-that, it might be thought that the evidential standards for the former must be, at least, as high as standards for the latter. And any additional pro-attitude might be thought to require a further layer of justification not required for cases of belief-that.

Belief-in may be, in general, less susceptible to alternations in the face of unfavourable evidence than belief-that. A believe who encounters evidence against God's existence may remain unshaken in his belief, in part because the evidence does not bear on his pro-attitude. So long as this is united with his belief that God exists, the reasonably so in a way that an ordinary propositional belief that would not.

Some philosophers think that the category of knowing for which true. Justified believing (accepting) is a requirement constituting only a species of Propositional knowledge, construed as an even broader category. They have proposed various examples of 'PK' that do not satisfy the belief and/ort justification conditions of the tripartite analysis. Such cases are often recognized by analyses of Propositional knowledge in terms of powers, capacities, or abilities. For instance, Alan R. White (1982) treats 'PK' as merely the ability to provide a correct answer to a possible question, however, White may be equating 'producing' knowledge in the sense of producing 'the correct answer to a possible question' with 'displaying' knowledge in the sense of manifesting knowledge. (White, 1982). The latter can be done even by very young children and some non-human animals independently of their being asked questions, understanding questions, or recognizing answers to questions. Indeed, an example that has been proposed as an instance of knowing that 'h' without believing or accepting that 'h' can be modified so as to illustrate this point. Two examples concern an imaginary person who has no special training or information about horses or racing, but who in an experiment persistently and correctly picks the winners of upcoming horseraces. If the example is modified so that the hypothetical 'seer' never picks winners but only muses over whether those horses wight win, or only reports those horses winning, this behaviour should be as much of a candidate for the person's manifesting knowledge that the horse in question will win as would be the behaviour of picking it as a winner.

These considerations expose limitations in Edward Craig's analysis (1990) of the concept of knowing of a person's being a satisfactory information in relation to an inquirer who wants to find out whether or not 'h'. Craig realizes that counterexamples to his analysis appear to be constituted by Knower who is too recalcitrant to inform the inquirer, or to incapacitate to inform, or too discredited to be worth considering (as with the boy who cried 'Wolf'). Craig admits that this might make preferably some alternative view of knowledge as a different state that helps to explain the presence of the state of being a suitable informant when the latter does obtain. Such an alternate, which offers a recursive definition that concerns one's having the power to proceed in a way representing the state of affairs, causally involved in one's proceeding in this way. When combined with a suitable analysis of representing, this theory of propositional knowledge can be unified with a structurally similar analysis of knowing how to do something.

Knowledge and belief, according to most epistemologists, knowledge entails belief, so that I cannot know that such and such is the case unless I believe that such and such am the case. Others think this entailment thesis can be rendered more accurately if we substitute for belief some closely related attitude. For instance, several philosophers would prefer to say that knowledge entail psychological certainties (Prichard, 1950 and Ayer, 1956) or conviction (Lehrer, 1974) or acceptance (Lehrer, 1989). Nonetheless, there are arguments against all versions of the thesis that knowledge requires having a belief-like attitude toward the known. These arguments are given by philosophers who think that knowledge and belief (or a facsimile) are mutually incompatible (the incomparability thesis), or by ones who say that knowledge does not entail belief, or vice versa, so that each may exist without the other, but the two may also coexist (the separability thesis).

The incompatibility thesis is sometimes traced to Plato 429-347 Bc. , In view of his claim that knowledge is infallible while belief or opinion is fallible ('Republic' 476-9). But this claim would not support the thesis. Belief might be a component of an infallible form of knowledge in spite of the fallibility of belief. Perhaps, knowledge involves some factor that compensates for the fallibility of belief.

A. Duncan-Jones (1939: Also Vendler, 1978) cites linguistic evidence to back up the incompatibility thesis. He notes that people often say 'I do not believe she is guilty. I know she is' and the like, which suggest that belief rule out knowledge. However, as Lehrer (1974) indicates, the above exclamation is only a more emphatic way of saying 'I do not just believe she is guilty, I know she is' where 'just' makes it especially clear that the speaker is signalling that she has something more salient than mere belief, not that she has something inconsistent with belief, namely knowledge. Compare: 'You do not hurt him, you killed him'.

H.A. Prichard (1966) offers a defence of the incompatibility thesis that hinges on the equation of knowledge with certainty (both infallibility and psychological certitude) and the assumption that when we believe in the truth of a claim we are not certain about its truth. Given that belief always involves uncertainty while knowledge never dies, believing something rules out the possibility of knowing it. Unfortunately, however, Prichard gives 'us' no goods reason to grant that states of belief are never ones involving confidence. Conscious beliefs clearly involve some level of confidence, to suggest that we cease to believe things about which we are completely confident is bizarre.

A.D. Woozley (1953) defends a version of the separability thesis. Woozley's version, which deals with psychological certainty rather than belief per se, is that knowledge can exist in the absence of confidence about the item known, although might also be accompanied by confidence as well. Woozley remarks that the test of whether I know something is 'what I can do, where what I can do may include answering questions'. On the basis of this remark he suggests that even when people are unsure of the truth of a claim, they might know that the claim is true. We unhesitatingly attribute knowledge to people who give correct responses on examinations even if those people show no confidence in their answers. Woozley acknowledges, however, that it would be odd for those who lack confidence to claim knowledge. It would be peculiar to say, 'I am unsure my answer is true: Still, I know it is correct'. But this tension Woozley explains using a distinction between conditions under which we are justified in making a claim (such as a claim to know something), and conditions under which the claim we make are true. While 'I know such and such' might be true even if I am unsure whether such and such holds, nonetheless it would be inappropriate for me to claim that I know that such and such unless I were sure of the truth of my claim.

Colin Radford (1966) extends Woozley's defence of the separability thesis. In Radford's view, not only is knowledge compatible with the lack of certainty, it is also compatible with a complete lack of belief. He argues by example. In one example, Jean has forgotten that he learned some English history year's priori and yet he is able to give several correct responses to questions such as 'When did the Battle of Hastings occur'? Since he forgot that he took history, he considers the correct response to be no more than guesses. Thus, when he says that the Battle of Hastings took place in 1066 he would deny having the belief that the Battle of Hastings took place in 1066. A disposition he would deny being responsible (or having the right to be convincing) that 1066 was the correct date. Radford would nonetheless insist that Jean know when the Battle occurred, since clearly be remembering the correct date. Radford admits that it would be inappropriate for Jean to say that he knew when the Battle of Hastings occurred, but, like Woozley he attributes the impropriety to a fact about when it is and is not appropriate to claim knowledge. When we claim knowledge, we ought, at least to believe that we have the knowledge we claim, or else our behaviour is 'intentionally misleading'.

Those that agree with Radford's defence of the separability thesis will probably think of belief as an inner state that can be detected through introspection. That Jean lack's beliefs about English history are plausible on this Cartesian picture since Jean does not find himself with any beliefs about English history when we seek them out. One might criticize Radford, however, by rejecting that Cartesian view of belief. One could argue that some beliefs are thoroughly unconscious, for example. Or one could adopt a behaviourist conception of belief, such as Alexander Bain's (1859), according to which having beliefs is a matter of the way people are disposed to behave (and has not Radford already adopted a behaviourist conception of knowledge?) Since Jean gives the correct response when queried, a form of verbal behaviour, a behaviourist would be tempted to credit him with the belief that the Battle of Hastings occurred in 1066.

D.M. Armstrong (1873) takes a different tack against Radford. Jean does know that the Battle of Hastings took place in 1066. Armstrong will grant Radfod that point, in fact, Armstrong suggests that Jean believe that 1066 is not the date the Battle of Hastings occurred, for Armstrong equates the belief that such and such is just possible but no more than just possible with the belief that such and such is not the case. However, Armstrong insists, Jean also believes that the Battle did occur in 1066. After all, had Jean been mistaught that the Battle occurred in 1066, and subsequently 'guessed' that it took place in 1066, we would surely describe the situation as one in which Jean's false belief about the Battle became unconscious over time but persisted of a memory trace that was causally responsible for his guess. Out of consistency, we must describe Radford's original case as one that Jean's true belief became unconscious but persisted long enough to cause his guess. Thus, while Jean consciously believes that the Battle did not occur in 1066, unconsciously he does believe it occurred in 1066. So after all, Radford does not have a counterexample to the claim that knowledge entails belief.

Armstrong's response to Radford was to reject Radford's claim that the examinee lacked the relevant belief about English history. Another response is to argue that the examinee lacks the knowledge Radford attributes to him (cf. Sorenson, 1982). If Armstrong is correct in suggesting that Jean believes both that 1066 is and that it is not the date of the Battle of Hastings, one might deny Jean knowledge on the grounds that people who believe the denial of what they believe cannot be said t know the truth of their belief. Another strategy might be to compare the examine case with examples of ignorance given in recent attacks on externalist accounts of knowledge (needless to say. Externalists themselves would tend not to favour this strategy). Consider the following case developed by BonJour (1985): For no apparent reason, Samantha believes that she is clairvoyant. Again, for no apparent reason, she one day comes to believe that the President is in New York City, even though she has every reason to believe that the President is in Washington, D.C. In fact, Samantha is a completely reliable clairvoyant, and she has arrived at her belief about the whereabouts of the President thorough the power of her clairvoyance. Yet surely Samantha's belief is completely irrational. She is not justified in thinking what she does. If so, then she does not know where the President is. But Radford's examinee is unconventional. Even if Jean lacks the belief that Radford denies him, Radford does not have an example of knowledge that is unattended with belief. Suppose that Jean's memory had been sufficiently powerful to produce the relevant belief. As Radford says, in having every reason to suppose that his response is mere guesswork, and he has every reason to consider his belief false. His belief would be an irrational one, and hence one about whose truth Jean would be ignorant.

Least has been of mention to an approaching view from which 'perception' basis upon itself as a fundamental philosophical topic both for its central place in ant theory of knowledge, and its central place un any theory of consciousness. Philosophy in this area is constrained by a number of properties that we believe to hold of perception, (1) It gives 'us' knowledge of the world around 'us'. (2) We are conscious of that world by being aware of 'sensible qualities': Colour, sounds, tastes, smells, felt warmth, and the shapes and positions of objects in the environment. (3) Such consciousness is affected through highly complex information channels, such as the output of the three different types of colour-sensitive cells in the eye, or the channels in the ear for interpreting pulses of air pressure as frequencies of sound. (4) There ensues even more complex neurophysiological coding of that information, and eventually higher-order brain functions bring it about that we interpreted the information so received. (Much of this complexity has been revealed by the difficulties of writing programs enabling computers to recognize quite simple aspects of the visual scene.) The problem is to avoid thinking of here being a central, ghostly, conscious self, fed information in the same way that a screen if fed information by a remote television camera. Once such a model is in place, experience will seem like a veil getting between 'us' and the world, and the direct objects of perception will seem to be private items in an inner theatre or sensorium. The difficulty of avoiding this model is epically cute when we considered the secondary qualities of colour, sound, tactile feelings and taste, which can easily seem to have a purely private existence inside the perceiver, like sensation of pain. Calling such supposed items names like 'sense-data' or 'percepts' exacerbate the tendency, but once the model is in place, the first property, that perception gives 'us' knowledge of the world and its surrounding surfaces, is quickly threatened, for there will now seem little connection between these items in immediate experience and any independent reality. Reactions to this problem include 'scepticism' and 'idealism'.

A more hopeful approach is to claim that the complexities of (3) and (4) explain how we can have direct acquaintance of the world, than suggesting that the acquaintance we do have been at best indirect. It is pointed out that perceptions are not like sensation, precisely because they have a content, or outer-directed nature. To have a perception is to be aware of the world for being such-and-such a way, than to enjoy a mere modification of sensation. But such direct realism has to be sustained in the face of the evident personal (neurophysiological and other) factors determining how we perceive. One approach is to ask why it is useful to be conscious of what we perceive, when other aspects of our functioning work with information determining responses without any conscious awareness or intervention. A solution to this problem would offer the hope of making consciousness part of the natural world, than a strange optional extra.

Furthering, perceptual knowledge is knowledge acquired by or through the senses and includes most of what we know. We cross intersections when we see the light turn green, head for the kitchen when we smell the roast burning, squeeze the fruit to determine its ripeness, and climb out of bed when we hear the alarm ring. In each case we come to know something-that the light has turned green, that the roast is burning, that the melon is overripely, and that it is time to get up-by some sensory means. Seeing that the light has turned green is learning something-that, the light has turned green-by use of the eyes. Feeling that the melon is overripe is coming to know a fact-that the melon is overripe-by one's sense to touch. In each case the resulting knowledge is somehow based on, derived from or grounded in the sort of experience that characterizes the sense modality in question.

Much of our perceptual knowledge is indirect, dependent or derived. By this I mean that the facts we describe ourselves as learning, as coming to know, by perceptual means are pieces of knowledge that depend on our coming to know something else, some other fact, in a more direct way. We see, by the gauge, that we need gas, see, by the newspapers, that our team has lost again, see, by her expression, that she is nervous. This derived or dependent sort of knowledge is particularly prevalent in the cases of vision, but it occurs, to a lesser degree, in every sense modality. We install bells and other noise-makers so that we calm for example, hear (by the bell) that someone is at the door and (by the alarm) that its time to get up. When we obtain knowledge in this way, it is clear that unless one sees-hence, comes to know something about the gauge (that it says) and (hence, know) that one is described as coming to know by perceptual means. If one cannot hear that the bell is ringing, one cannot-in at least in this way-hear that one's visitors have arrived. In such cases one sees (hears, smells, etc.) that 'a' is 'F', coming to know thereby that 'a' is 'F', by seeing (hearing, etc.) that some other condition, 'b's' being 'G', obtains when this occurs, the knowledge (that 'a' is 'F') is derived from, or dependent on, the more basic perceptual knowledge that 'b' is 'G'.

Perhaps as a better strategy is to tie an account save that part that evidence could justify explanation for it is its truth alone. Since, at least the times of Aristotle philosophers of explanatory knowledge have emphasized of its importance that, in its simplest therms, we want to know not only what is the composite peculiarities and particular points of issue but also why it is. This consideration suggests that we define an explanation as an answer to a why-question. Such a definition would, however, be too broad, because some why-questions are requests for consolation (Why did my son have to die?) Or moral justification (Why should women not be paid the same as men for the same work?) It would also be too narrow because some explanations are responses to how-questions (How does radar work?) Or how-possibility-questions (How is it possible for cats always to land their feet?)

In its overall sense, 'to explain' means to make clear, to make plain, or to provide understanding. Definitions of this sort are philosophically unhelpful, for the terms used in the deficient are no less problematic than the term to be defined. Moreover, since a wide variety of things require explanation, and since many different types of explanation exist, as more complex explanation is required. To facilitate the requirement leaves, least of mention, for us to consider by introduction a bit of technical terminology. The term 'explanation' is used to refer to that which is to be explained: The term 'explanans' refer to that which does the explaining, the explanans and the explanation taken together constitute the explanation.

One common type of explanation occurs when deliberate human actions are explained in terms of conscious purposes. 'Why did you go to the pharmacy yesterday?' 'Because I had a headache and needed to get some aspirin.' It is tacitly assumed that aspirin is an appropriate medication for headaches and that going to the pharmacy would be an efficient way of getting some. Such explanations are, of course, teleological, referring, ss they do, to goals. The explanans are not the realisation of a future goal - if the pharmacy happened to be closed for stocktaking the aspirin would have been obtained there, bu t that would not invalidate the explanation. Some philosophers would say that the antecedent desire to achieve the end is what doers the explaining: Others might say that the explaining is done by the nature of the goal and the fact that the action promoted the chances of realizing it. (Taylor, 1964). In that it should not be automatically being assumed that such explanations are causal. Philosophers differ considerably on whether these explanations are to be framed in terms of cause or reason, but the distinction cannot be used to show that the relation between reasons and the actions they justify is in no way causal, and there are many differing analyses of such concepts as intention and agency. Expanding the domain beyond consciousness, Freud maintained, in addition, that much human behaviour can be explained in terms of unconscious and conscious wishes. Those Freudian explanations should probably be construed as basically causal.

Problems arise when teleological explanations are offered in other context. The behaviour of non-human animals is often explained in terms of purpose, e.g., the mouse ran to escape from the cat. In such cases the existence of conscious purpose seems dubious. The situation is still more problematic when a supr-empirical purpose in invoked, e.g., the explanations of living species in terms of God's purpose, or the vitalistic explanations of biological phenomena in terms of a entelechy or vital principle. In recent years an 'anthropic principle' has received attention in cosmology (Barrow and Tipler, 1986). All such explanations have been condemned by many philosophers an anthropomorphic.

Nevertheless, philosophers and scientists often maintain that functional explanations play an important an legitimate role in various sciences such as, evolutionary biology, anthropology and sociology. For example, of the peppered moth in Liverpool, the change in colour from the light phase to the dark phase and back again to the light phase provided adaption to a changing environment and fulfilled the function of reducing predation on the spacies. In the study of primitive soviets anthropologists have insisted that various rituals the (rain dance) which may be inefficacious in braining about their manifest goals (producing rain), actually cohesion at a period of stress (often a drought). Philosophers who admit teleological and/or functional explanations in common sense and science oftentimes take pans to argue that such explanations can be annualized entirely in terms of efficient causes, thereby escaping the charge of anthropomorphism (Wright, 1976): Again, however, not all philosophers agree.

Causal theories of Propositional knowledge differ over whether they deviate from the tripartite analysis by dropping the requirements that one's believing (accepting) that 'h' be justified. The same variation occurs regarding reliability theories, which present the Knower as reliable concerning the issue of whether or not 'h', in the sense that some of one's cognitive or epistemic states, ?, are such that, given further characteristics of oneself-possibly including relations to factors external to one and which one may not be aware-it is nomologically necessary (or at least probable) that 'h'. In some versions, the reliability is required to be 'global' in as far as it must concern a nomologically (probabilistic-relationship) relationship that states of type ? to the acquisition of true beliefs about a wider range of issues than merely whether or not 'h'. There is also controversy about how to delineate the limits of what constitutes a type of relevant personal state or characteristic. (For example, in a case where Mr Notgot has not been shamming and one does know thereby that someone in the office owns a Ford, such as a way of forming beliefs about the properties of persons spatially close to one, or instead something narrower, such as a way of forming beliefs about Ford owners in offices partly upon the basis of their relevant testimony?)

One important variety of reliability theory is a conclusive reason account, which includes a requirement that one's reasons for believing that 'h' be such that in one's circumstances, if h* were not to occur then, e.g., one would not have the reasons one does for believing that 'h', or, e.g., one would not believe that 'h'. Roughly, the latter is demanded by theories that treat a Knower as 'tracking the truth', theories that include the further demand that is roughly, if it were the case, that 'h', then one would believe that 'h'. A version of the tracking theory has been defended by Robert Nozick (1981), who adds that if what he calls a 'method' has been used to arrive at the belief that 'h', then the antecedent clauses of the two conditionals that characterize tracking will need to include the hypothesis that one would employ the very same method.

But unless more conditions are added to Nozick's analysis, it will be too weak to explain why one lack's knowledge in a version of the last variant of the tricky Mr Notgot case described above, where we add the following details: (a) Mr Notgot's compulsion is not easily changed, (b) while in the office, Mr Notgot has no other easy trick of the relevant type to play on one, and finally for one's belief that 'h', not by reasoning through a false belief ut by basing belief that 'h', upon a true existential generalization of one's evidence.

Nozick's analysis is in addition too strong to permit anyone ever to know that 'h': 'Some of my beliefs about beliefs might be otherwise, e.g., I might have rejected on of them'. If I know that 'h5' then satisfaction of the antecedent of one of Nozick's conditionals would involve its being false that 'h5', thereby thwarting satisfaction of the consequent's requirement that I not then believe that 'h5'. For the belief that 'h5' is itself one of my beliefs about beliefs (Shope, 1984).

Some philosophers think that the category of knowing for which is true. Justified believing (accepting) is a requirement constituting only a species of Propositional knowledge, construed as an even broader category. They have proposed various examples of 'PK' that do not satisfy the belief and/ort justification conditions of the tripartite analysis. Such cases are often recognized by analyses of Propositional knowledge in terms of powers, capacities, or abilities. For instance, Alan R. White (1982) treats 'PK' as merely the ability to provide a correct answer to a possible question. White may be equating 'producing' knowledge in the sense of producing 'the correct answer to a possible question' with 'displaying' knowledge in the sense of manifesting knowledge. (White, 1982). The latter can be done even by very young children and some non-human animals independently of their being asked questions, understanding questions, or recognizing answers to questions. Indeed, an example that has been proposed as an instance of knowing that 'h' without believing or accepting that 'h' can be modified so as to illustrate this point. Two examples concerns an imaginary person who has no special training or information about horses or racing, but who in an experiment persistently and correctly picks the winners of upcoming horseraces. If the example is modified so that the hypothetical 'seer' never picks winners but only muses over whether those horses wight win, or only reports those horses winning, this behaviour should be as much of a candidate for the person's manifesting knowledge that the horse in question will win as would be the behaviour of picking it as a winner.

These considerations expose limitations in Edward Craig's analysis (1990) of the concept of knowing of a person's being a satisfactory informants in relation to an inquirer who wants to find out whether or not 'h'. Craig realizes that counterexamples to his analysis appear to be constituted by Knower who are too recalcitrant to inform the inquirer, or too incapacitate to inform, or too discredited to be worth considering (as with the boy who cried 'Wolf'). Craig admits that this might make preferable some alternative view of knowledge as a different state that helps to explain the presence of the state of being a suitable informant when the latter does obtain. Such the alternate, which offers a recursive definition that concerns one's having the power to proceed in a way representing the state of affairs, causally involved in one's proceeding in this way. When combined with a suitable analysis of representing, this theory of propositional knowledge can be unified with a structurally similar analysis of knowing how to do something.

Knowledge and belief, according to most epistemologists, knowledge entails belief, so that I cannot know that such and such is the case unless I believe that such and such is the case. Others think this entailment thesis can be rendered more accurately if we substitute for belief some closely related attitude. For instance, several philosophers would prefer to say that knowledge entail psychological certainties (Prichard, 1950 and Ayer, 1956) or conviction (Lehrer, 1974) or acceptance (Lehrer, 1989). Nonetheless, there are arguments against all versions of the thesis that knowledge requires having a belief-like attitude toward the known. These arguments are given by philosophers who think that knowledge and belief (or a facsimile) are mutually incompatible (the incomparability thesis), or by ones who say that knowledge does not entail belief, or vice versa, so that each may exist without the other, but the two may also coexist (the separability thesis).

The incompatibility thesis is sometimes traced to Plato (429-347 Bc) in view of his claim that knowledge is infallible while belief or opinion is fallible ('Republic' 476-9). But this claim would not support the thesis. Belief might be a component of an infallible form of knowledge in spite of the fallibility of belief. Perhaps, knowledge involves some factor that compensates for the fallibility of belief.

A. Duncan-Jones (1939: Also Vendler, 1978) cite linguistic evidence to back up the incompatibility thesis. He notes that people often say 'I do not believe she is guilty. I know she is' and the like, which suggest that belief rule out knowledge. However, as Lehrer (1974) indicates, the above exclamation is only a more emphatic way of saying 'I do not just believe she is guilty, I know she is' where 'just' makes it especially clear that the speaker is signalling that she has something more salient than mere belief, not that she has something inconsistent with belief, namely knowledge. Compare: 'You do not hurt him, you killed him.'

H.A. Prichard (1966) offers a defence of the incompatibility thesis that hinges on the equation of knowledge with certainty (both infallibility and psychological certitude) and the assumption that when we believe in the truth of a claim we are not certain about its truth. Given that belief always involves uncertainty while knowledge never dies, believing something rules out the possibility of knowing it. Unfortunately, however, Prichard gives 'us' no goods reason to grant that states of belief are never ones involving confidence. Conscious beliefs clearly involve some level of confidence, to suggest that we cease to believe things about which we are completely confident is bizarre.

A.D. Woozley (1953) defends a version of the separability thesis. Woozley's version, which deals with psychological certainty rather than belief per se, is that knowledge can exist in the absence of confidence about the item known, although might also be accompanied by confidence as well. Woozley remarks that the test of whether I know something is 'what I can do, where what I can do may include answering questions.' On the basis of this remark he suggests that even when people are unsure of the truth of a claim, they might know that the claim is true. We unhesitatingly attribute knowledge to people who give correct responses on examinations even if those people show no confidence in their answers. Woozley acknowledges, however, that it would be odd for those who lack confidence to claim knowledge. It would be peculiar to say, I am unsure that for whatever reason my answer is true: Still, I know it is correct But this tension Woozley explains using a distinction between conditions under which we are justified in making a claim (such as a claim to know something), and conditions under which the claim we make is true. While 'I know such and such' might be true even if I am unsure whether such and such holds, nonetheless it would be inappropriate for me to claim that I know that such and such unless I were sure of the truth of my claim.

Colin Radford (1966) extends Woozley's defence of the separability thesis. In Radford's view, not only is knowledge compatible with the lack of certainty, it is also compatible with a complete lack of belief. He argues by example. In one example, Jean has forgotten that he learned some English history year's priori and yet he is able to give several correct responses to questions such as 'When did the Battle of Hastings occur?' Since he forgot that he took history, he considers the correct response to be no more than guesses. Thus, when he says that the Battle of Hastings took place in 1066 he would deny having the belief that the Battle of Hastings took place in 1066. A disposition he would deny being responsible (or having the right to be convincing) that 1066 was the correct date. Radford would none the less insist that Jean know when the Battle occurred, since clearly be remembering the correct date. Radford admits that it would be inappropriate for Jean to say that he knew when the Battle of Hastings occurred, but, like Woozley he attributes the impropriety to a fact about when it is and is not appropriate to claim knowledge. When we claim knowledge, we ought, at least to believe that we have the knowledge we claim, or else our behaviour is 'intentionally misleading'.

Those that agree with Radford's defence of the separability thesis will probably think of belief as an inner state that can be detected through introspection. That Jean lack's beliefs about English history is plausible on this Cartesian picture since Jean does not find himself with any beliefs about English history when ne seek them out. One might criticize Radford, however, by rejecting that Cartesian view of belief. One could argue that some beliefs are thoroughly unconscious, for example. Or one could adopt a behaviourist conception of belief, such as Alexander Bain's (1859), according to which having beliefs is a matter of the way people are disposed to behave (and has not Radford already adopted a behaviourist conception of knowledge?) Since Jean gives the correct response when queried, a form of verbal behaviour, a behaviourist would be tempted to credit him with the belief that the Battle of Hastings occurred in 1066.

D.M. Armstrong (1873) takes a different tack against Radford. Jean does know that the Battle of Hastings took place in 1066. Armstrong will grant Radfod that point, in fact, Armstrong suggests that Jean believe that 1066 is not the date the Battle of Hastings occurred, for Armstrong equates the belief that such and such is just possible but no more than just possible with the belief that such and such is not the case. However, Armstrong insists, Jean also believes that the Battle did occur in 1066. After all, had Jean been mistaught that the Battle occurred in 1066, and subsequently 'guessed' that it took place in 1066, we would surely describe the situation as one in which Jean's false belief about the Battle became unconscious over time but persisted of a memory trace that was causally responsible for his guess. Out of consistency, we must describe Radford's original case as one that Jean's true belief became unconscious but persisted long enough to cause his guess. Thus, while Jean consciously believes that the Battle did not occur in 1066, unconsciously he does believe it occurred in 1066. So after all, Radford does not have a counterexample to the claim that knowledge entails belief.

Armstrong's response to Radford was to reject Radford's claim that the examinee lacked the relevant belief about English history. Another response is to argue that the examinee lacks the knowledge Radford attributes to him (cf. Sorenson, 1982). If Armstrong is correct in suggesting that Jean believes both that 1066 is and that it is not the date of the Battle of Hastings, one might deny Jean knowledge on the grounds that people who believe the denial of what they believe cannot be said t know the truth of their belief. Another strategy might be to compare the examine case with examples of ignorance given in recent attacks on externalist accounts of knowledge (needless to say. Externalists themselves would tend not to favour this strategy). Consider the following case developed by BonJour (1985): For no apparent reason, Samantha believes that she is clairvoyant. Again, for no apparent reason, she one day comes to believe that the President is in New York City, even though she has every reason to believe that the President is in Washington, D.C. In fact, Samantha is a completely reliable clairvoyant, and she has arrived at her belief about the whereabouts of the President thorough the power of her clairvoyance. Yet surely Samanthas belief is completely irrational. She is not justified in thinking what she does. If so, then she does not know where the President is. But Radford's examinee is unconventional. Even if Jean lacks the belief that Radford denies him, Radford does not have an example of knowledge that is unattended with belief. Suppose that Jean's memory had been sufficiently powerful to produce the relevant belief. As Radford says, in having every reason to suppose that his response is mere guesswork, and he has every reason to consider his belief false. His belief would be an irrational one, and hence one about whose truth Jean would be ignorant.

Least has been of mention to an approaching view from which 'perception' basis upon itself as a fundamental philosophical topic both for its central place in ant theory of knowledge, and its central place un any theory of consciousness. Philosophy in this area is constrained by a number of properties that we believe to hold of perception, (1) It gives 'us' knowledge of the world around 'us,' (2) We are conscious of that world by being aware of 'sensible qualities': Colour, sounds, tastes, smells, felt warmth, and the shapes and positions of objects in the environment. (3) Such consciousness is effected through highly complex information channels, such as the output of the three different types of colour-sensitive cells in the eye, or the channels in the ear for interpreting pulses of air pressure as frequencies of sound. (4) There ensues even more complex neurophysiological coding of that information, and eventually higher-order brain functions bring it about that we interpreted the information so received. (Much of this complexity has been revealed by the difficulties of writing programs enabling computers to recognize quite simple aspects of the visual scene.) The problem is to avoid thinking of here being a central, ghostly, conscious self, fed information in the same way that a screen if fed information by a remote television camera. Once such a model is in place, experience will seem like a veil getting between 'us' and the world, and the direct objects of perception will seem to be private items in an inner theatre or sensorium. The difficulty of avoiding this model is epically cute when we considered the secondary qualities of colour, sound, tactile feelings and taste, which can easily seem to have a purely private existence inside the perceiver, like sensation of pain. Calling such supposed items names like 'sense-data' or 'percepts' exacerbates the tendency, but once the model is in place, the first property, that perception gives 'us' knowledge of the world and its surrounding surfaces, is quickly threatened, for there will now seem little connection between these items in immediate experience and any independent reality. Reactions to this problem include 'scepticism' and 'idealism.'

A more hopeful approach is to claim that the complexities of (3) and (4) explain how we can have direct acquaintance of the world, than suggesting that the acquaintance we do have been at best indirect. It is pointed out that perceptions are not like sensation, precisely because they have a content, or outer-directed nature. To have a perception is to be aware of the world for being such-and-such a way, than to enjoy a mere modification of sensation. But such direct realism has to be sustained in the face of the evident personal (neurophysiological and other) factors determining how we perceive. One approach is to ask why it is useful to be conscious of what we perceive, when other aspects of our functioning work with information determining responses without any conscious awareness or intervention. A solution to this problem would offer the hope of making consciousness part of the natural world, than a strange optional extra.

Furthering, perceptual knowledge is knowledge acquired by or through the senses and includes most of what we know. We cross intersections when we see the light turn green, head for the kitchen when we smell the roast burning, squeeze the fruit to determine its ripeness, and climb out of bed when we hear the alarm ring. In each case we come to know something-that the light has turned green, that the roast is burning, that the melon is overripe, and that it is time to get up-by some sensory means. Seeing that the light has turned green is learning something-that, the light has turned green-by use of the eyes. Feeling that the melon is overripe is coming to know a fact-that the melon is overripe-by one's sense to touch. In each case the resulting knowledge is somehow based on, derived from or grounded in the sort of experience that characterizes the sense modality in question.

Much as much of our perceptual knowledge is indirect, dependent or derived. By this I mean that the facts we describe ourselves as learning, as coming to know, by perceptual means are pieces of knowledge that depend on our coming to know something else, some other fact, in a more direct way. We see, by the gauge, that we need gas, see, by the newspapers, that our team has lost again, see, by her expression, that she is nervous. This derived or dependent sort of knowledge is particularly prevalent in the cases of vision, but it occurs, to a lesser degree, in every sense modality. We install bells and other noise-makers so that we calm for example, hear (by the bell) that someone is at the door and (by the alarm) that its time to get up. When we obtain knowledge in this way, it is clear that unless one sees-hence, comes to know something about the gauge (that it says) and (hence, know) that one is described as coming to know by perceptual means. If one cannot hear that the bell is ringing, one cannot-in at least in this way-hear that one's visitors have arrived. In such cases one sees (hears, smells, etc.) that 'a' is 'F', coming to know thereby that 'a' is 'F', by seeing (hearing, etc.) that some other condition, 'b's' being 'G', obtains when this occurs, the knowledge (that 'a' is 'F') is derived from, or dependent on, the more basic perceptual knowledge that 'b' is 'G'.

And finally, the representational Theory of mind, (which goes back at least to Aristotle) takes as its starting point commonsense mental states, such as thoughts, beliefs, desires, perceptions and images. Such states are said to have 'intentionality' - they are about or refer to things, and may be evaluated with respect to properties like consistency, truth, appropriateness and accuracy. (For example, the thought that cousins are not related is inconsistent, the belief that Elvis is dead is true, the desire to eat the moon is inappropriate, a visual experience of a ripe strawberry as red is accurate, an image of George W. Bush with dreadlocks is inaccurate.)

The Representational Theory of Mind, defines such intentional mental states as relations to mental representations, and explains the intentionality of the former in terms of the semantic properties of the latter. For example, to believe that Elvis is dead is to be appropriately related to a mental representation whose propositional content is that Elvis is dead. (The desire that Elvis be dead, the fear that he is dead, the regret that he is dead, etc., involve different relations to the same mental representation.) To perceive a strawberry is to have a sensory experience of some kind which is appropriately related to (e.g., caused by) the strawberry Representational theory of mind also understands mental processes such as thinking, reasoning and imagining as sequences of intentional mental states. For example, to imagine the moon rising over a mountain is to entertain a series of mental images of the moon (and a mountain). To infer a proposition q from the proposition's p and if 'p' then 'q' is (among other things) to have a sequence of thoughts of the form 'p', 'if p' then 'q', 'q'.

Contemporary philosophers of mind have typically supposed (or at least hoped) that the mind can be naturalized -, i.e., that all mental facts have explanations in the terms of natural science. This assumption is shared within cognitive science, which attempts to provide accounts of mental states and processes in terms (ultimately) of features of the brain and central nervous system. In the course of doing so, the various sub-disciplines of cognitive science (including cognitive and computational psychology and cognitive and computational neuroscience) postulate a number of different kinds of structures and processes, many of which are not directly implicated by mental states and processes as commonsensical conceived. There remains, however, a shared commitment to the idea that mental states and processes are to be explained in terms of mental representations.

In philosophy, recent debates about mental representation have centred around the existence of propositional attitudes (beliefs, desires, etc.) and the determination of their contents (how they come to be about what they are about), and the existence of phenomenal properties and their relation to the content of thought and perceptual experience. Within cognitive science itself, the philosophically relevant debates have been focussed on the computational architecture of the brain and central nervous system, and the compatibility of scientific and commonsense accounts of mentality.

Intentional Realists such as Dretske (e.g., 1988) and Fodor (e.g., 1987) note that the generalizations we apply in everyday life in predicting and explaining each other's behaviour (often collectively referred to as 'folk psychology') are both remarkably successful and indispensable. What a person believes, doubts, desires, fears, etc. is a highly reliable indicator of what that person will do. We have no other way of making sense of each other's behaviour than by ascribing such states and applying the relevant generalizations. We are thus committed to the basic truth of commonsense psychology and, hence, to the existence of the states its generalizations refer to. (Some realists, such as Fodor, also hold that commonsense psychology will be vindicated by cognitive science, given that propositional attitudes can be construed as computational relations to mental representations.)

Intentional Eliminativists, such as Churchland, (perhaps) Dennett and (at one time) Stich argue that no such things as propositional attitudes (and their constituent representational states) are implicated by the successful explanation and prediction of our mental lives and behaviour. Churchland denies that the generalizations of commonsense propositional-attitude psychology are true. He (1981) argues that folk psychology is a theory of the mind with a long history of failure and decline, and that it resists incorporation into the framework of modern scientific theories (including cognitive psychology). As such, it is comparable to alchemy and phlogiston theory, and ought to suffer a comparable fate. Commonsense psychology is false, and the states (and representations) it postulates simply don't exist. (It should be noted that Churchland is not an eliminativist about mental representation tout court.

Dennett (1987) grants that the generalizations of commonsense psychology are true and indispensable, but denies that this is sufficient reason to believe in the entities they appear to refer to. He argues that to give an intentional explanation of a system's behaviour is merely to adopt the 'intentional stance' toward it. If the strategy of assigning contentful states to a system and predicting and explaining its behaviour (on the assumption that it is rational -, i.e., that it behaves as it should, given the propositional attitudes it should have in its environment) is successful, then the system is intentional, and the propositional-attitude generalizations we apply to it are true. But there is nothing more to having a propositional attitude than this.

Though he has been taken to be thus claiming that intentional explanations should be construed instrumentally, Dennett (1991) insists that he is a 'moderate' realist about propositional attitudes, since he believes that the patterns in the behaviour and behavioural dispositions of a system on the basis of which we (truly) attribute intentional states to it are objectively real. In the event that there are two or more explanatorily adequate but substantially different systems of intentional ascriptions to an individual, however, Dennett claims there is no fact of the matter about what the system believes (1987, 1991). This does suggest an irrealism at least with respect to the sorts of things Fodor and Dretske take beliefs to be; though it is not the view that there is simply nothing in the world that makes intentional explanations true.

(Davidson 1973, 1974 and Lewis 1974 also defend the view that what it is to have a propositional attitude is just to be interpretable in a particular way. It is, however, not entirely clear whether they intend their views to imply irrealism about propositional attitudes.). Stich (1983) argues that cognitive psychology does not (or, in any case, should not) taxonomize mental states by their semantic properties at all, since attribution of psychological states by content is sensitive to factors that render it problematic in the context of a scientific psychology. Cognitive psychology seeks causal explanations of behaviour and cognition, and the causal powers of a mental state are determined by its intrinsic 'structural' or 'syntactic' properties. The semantic properties of a mental state, however, are determined by its extrinsic properties -, e.g., its history, environmental or intra-mental relations. Hence, such properties cannot figure in causal-scientific explanations of behaviour. (Fodor 1994 and Dretske 1988 are realist attempts to come to grips with some of these problems.) Stich proposes a syntactic theory of the mind, on which the semantic properties of mental states play no explanatory role.

It is a traditional assumption among realists about mental representations that representational states come in two basic varieties (Boghossian 1995). There are those, such as thoughts, which are composed of concepts and have no phenomenal ('what-it's-like') features ('Qualia'), and those, such as sensory experiences, which have phenomenal features but no conceptual constituents. (Non-conceptual content is usually defined as a kind of content that states of a creature lacking concepts but, nonetheless enjoy. On this taxonomy, mental states can represent either in a way analogous to expressions of natural languages or in a way analogous to drawings, paintings, maps or photographs. (Perceptual states such as seeing that something is blue, are sometimes thought of as hybrid states, consisting of, for example, a Non-conceptual sensory experience and a thought, or some more integrated compound of sensory and conceptual components.)

Some historical discussions of the representational properties of mind (e.g., Aristotle 1984, Locke 1689/1975, Hume 1739/1978) seem to assume that Non-conceptual representations - percepts ('impressions'), images ('ideas') and the like - are the only kinds of mental representations, and that the mind represents the world in virtue of being in states that resemble things in it. On such a view, all representational states have their content in virtue of their phenomenal features. Powerful arguments, however, focussing on the lack of generality (Berkeley 1975), ambiguity (Wittgenstein 1953) and non-compositionality (Fodor 1981) of sensory and imagistic representations, as well as their unsuitability to function as logical (Frége 1918/1997, Geach 1957) or mathematical (Frége 1884/1953) concepts, and the symmetry of resemblance (Goodman 1976), convinced philosophers that no theory of mind can get by with only Non-conceptual representations construed in this way.

Contemporary disagreement over Non-conceptual representation concerns the existence and nature of phenomenal properties and the role they play in determining the content of sensory experience. Dennett (1988), for example, denies that there are such things as Qualia at all; while Brandom (2002), McDowell (1994), Rey (1991) and Sellars (1956) deny that they are needed to explain the content of sensory experience. Among those who accept that experiences have phenomenal content, some (Dretske, Lycan, Tye) argue that it is reducible to a kind of intentional content, while others (Block, Loar, Peacocke) argue that it is irreducible.

The representationalist thesis is often formulated as the claim that phenomenal properties are representational or intentional. However, this formulation is ambiguous between a reductive and a non-deductive claim (though the term 'representationalism' is most often used for the reductive claim). On one hand, it could mean that the phenomenal content of an experience is a kind of intentional content (the properties it represents). On the other, it could mean that the (irreducible) phenomenal properties of an experience determine an intentional content. Representationalists such as Dretske, Lycan and Tye would assent to the former claim, whereas phenomenalists such as Block, Chalmers, Loar and Peacocke would assent to the latter. (Among phenomenalists, there is further disagreement about whether Qualia are intrinsically representational (Loar) or not (Block, Peacocke).

Most (reductive) representationalists are motivated by the conviction that one or another naturalistic explanation of intentionality is, in broad outline, correct, and by the desire to complete the naturalization of the mental by applying such theories to the problem of phenomenality. (Needless to say, most phenomenalists (Chalmers is the major exception) are just as eager to naturalize the phenomenal - though not in the same way.)

The main argument for representationalism appeals to the transparency of experience. The properties that characterize what it's like to have a perceptual experience are presented in experience as properties of objects perceived: in attending to an experience, one seems to 'see through it' to the objects and properties it is experiences of. They are not presented as properties of the experience itself. If nonetheless they were properties of the experience, perception would be massively deceptive. But perception is not massively deceptive. According to the representationalist, the phenomenal character of an experience is due to its representing objective, non-experiential properties. (In veridical perception, these properties are locally instantiated; in illusion and hallucination, they are not.) On this view, introspection is indirect perception: one comes to know what phenomenal features one's experience has by coming to know what objective features it represents.

In order to account for the intuitive differences between conceptual and sensory representations, representationalists appeal to their structural or functional differences. Dretske (1995), for example, distinguishes experiences and thoughts on the basis of the origin and nature of their functions: an experience of a property 'P' is a state of a system whose evolved function is to indicate the presence of 'P' in the environment; a thought representing the property 'P', on the other hand, is a state of a system whose assigned (learned) function is to calibrate the output of the experiential system. Rey (1991) takes both thoughts and experiences to be relations to sentences in the language of thought, and distinguishes them on the basis of (the functional roles of) such sentences' constituent predicates. Lycan (1987, 1996) distinguishes them in terms of their functional-computational profiles. Tye (2000) distinguishes them in terms of their functional roles and the intrinsic structure of their vehicles: thoughts are representations in a language-like medium, whereas experiences are image-like representations consisting of 'symbol-filled arrays.' (The account of mental images in Tye 1991.)

Phenomenalists tend to make use of the same sorts of features (function, intrinsic structure) in explaining some of the intuitive differences between thoughts and experiences; but they do not suppose that such features exhaust the differences between phenomenal and non-phenomenal representations. For the phenomenalist, it is the phenomenal properties of experiences - Qualia themselves - that constitute the fundamental difference between experience and thought. Peacocke (1992), for example, develops the notion of a perceptual 'scenario' (an assignment of phenomenal properties to coordinates of a three-dimensional egocentric space), whose content is 'correct' (a semantic property) if in the corresponding 'scene' (the portion of the external world represented by the scenario) properties are distributed as their phenomenal analogues are in the scenario.

Another sort of representation championed by phenomenalists (e.g., Block, Chalmers (2003) and Loar (1996)) is the 'phenomenal concept' -, a conceptual/phenomenal hybrid consisting of a phenomenological 'sample' (an image or an occurrent sensation) integrated with (or functioning as) a conceptual component. Phenomenal concepts are postulated to account for the apparent fact (among others) that, as McGinn (1991) puts it, 'you cannot form [introspective] concepts of conscious properties unless you yourself instantiate those properties.' One cannot have a phenomenal concept of a phenomenal property 'P', and, hence, phenomenal beliefs about P, without having experience of 'P', because 'P' itself is (in some way) constitutive of the concept of 'P'. (Jackson 1982, 1986 and Nagel 1974.)

Though imagery has played an important role in the history of philosophy of mind, the important contemporary literature on it is primarily psychological. In a series of psychological experiments done in the 1970s (summarized in Kosslyn 1980 and Shepard and Cooper 1982), subjects' response time in tasks involving mental manipulation and examination of presented figures was found to vary in proportion to the spatial properties (size, orientation, etc.) of the figures presented. The question of how these experimental results are to be explained has kindled a lively debate on the nature of imagery and imagination.

Kosslyn (1980) claims that the results suggest that the tasks were accomplished via the examination and manipulation of mental representations that they have spatial properties, i.e., pictorial representations, or images. Others, principally Pylyshyn (1979, 1981, 2003), argue that the empirical facts can be explained in terms exclusively of discursive, or propositional representations and cognitive processes defined over them. (Pylyshyn takes such representations to be sentences in a language of thought.)

The idea that pictorial representations are literally pictures in the head is not taken seriously by proponents of the pictorial view of imagery. The claim is, rather, that mental images represent in a way that is relevantly like the way pictures represent. (Attention has been focussed on visual imagery - hence the designation 'pictorial'; Though of course, there may imagery in other modalities - auditory, olfactory, etc. - as well.)

The distinction between pictorial and discursive representation can be characterized in terms of the distinction between analog and digital representation (Goodman 1976). This distinction has itself been variously understood (Fodor & Pylyshyn 1981, Goodman 1976, Haugeland 1981, Lewis 1971, McGinn 1989), though a widely accepted construal is that analog representation is continuous (i.e., in virtue of continuously variable properties of the representation), while digital representation is discrete (i.e., in virtue of properties a representation either has or doesn't have) (Dretske 1981). (An analog/digital distinction may also be made with respect to cognitive processes. (Block 1983.)) On this understanding of the analog/digital distinction, imagistic representations, which represent in virtue of properties that may vary continuously (such for being more or less bright, loud, vivid, etc.), would be analog, while conceptual representations, whose properties do not vary continuously (a thought cannot be more or less about Elvis: either it is or it is not) would be digital.

It might be supposed that the pictorial/discursive distinction is best made in terms of the phenomenal/nonphenomenal distinction, but it is not obvious that this is the case. For one thing, there may be nonphenomenal properties of representations that vary continuously. Moreover, there are ways of understanding pictorial representation that presuppose neither phenomenality nor analogicity. According to Kosslyn (1980, 1982, 1983), a mental representation is 'quasi-pictorial' when every part of the representation corresponds to a part of the object represented, and relative distances between parts of the object represented are preserved among the parts of the representation. But distances between parts of a representation can be defined functionally rather than spatially - for example, in terms of the number of discrete computational steps required to combine stored information about them. (Rey 1981.)

Tye (1991) proposes a view of images on which they are hybrid representations, consisting both of pictorial and discursive elements. On Tye's account, images are '(labelled) interpreted symbol-filled arrays.' The symbols represent discursively, while their arrangement in arrays has representational significance (the location of each 'cell' in the array represents a specific viewer-centred 2-D location on the surface of the imagined object)

The contents of mental representations are typically taken to be abstract objects (properties, relations, propositions, sets, etc.). A pressing question, especially for the naturalist, is how mental representations come to have their contents. Here the issue is not how to naturalize content (abstract objects can't be naturalized), but, rather, how to provide a naturalistic account of the content-determining relations between mental representations and the abstract objects they express. There are two basic types of contemporary naturalistic theories of content-determination, causal-informational and functional.

Causal-informational theories hold that the content of a mental representation is grounded in the information it carries about what does (Devitt 1996) or would (Fodor 1987, 1990) cause it to occur. There is, however, widespread agreement that causal-informational relations are not sufficient to determine the content of mental representations. Such relations are common, but representation is not. Tree trunks, smoke, thermostats and ringing telephones carry information about what they are causally related to, but they do not represent (in the relevant sense) what they carry information about. Further, a representation can be caused by something it does not represent, and can represent something that has not caused it.

The main attempts to specify what makes a causal-informational state a mental representation are Asymmetric Dependency Theories, the Asymmetric Dependency Theory distinguishes merely informational relations from representational relations on the basis of their higher-order relations to each other: informational relations depend upon representational relations, but not vice-versa. For example, if tokens of a mental state type are reliably caused by horses, cows-on-dark-nights, zebras-in-the-mist and Great Danes, then they carry information about horses, etc. If, however, such tokens are caused by cows-on-dark-nights, etc. because they were caused by horses, but not vice versa, then they represent horses.

According to Teleological Theories, representational relations are those a representation-producing mechanism has the selected (by evolution or learning) function of establishing. For example, zebra-caused horse-representations do not mean zebra, because the mechanism by which such tokens are produced has the selected function of indicating horses, not zebras. The horse-representation-producing mechanism that responds to zebras is malfunctioning.

Functional theories, hold that the content of a mental representation are well grounded in causal computational inferential relations to other mental portrayals other than mental representations. They differ on whether relata should include all other mental representations or only some of them, and on whether to include external states of affairs. The view that the content of a mental representation is determined by its inferential/computational relations with all other representations is holism; the view it is determined by relations to only some other mental states is localisms (or molecularism). (The view that the content of a mental state depends on none of its relations to other mental states is atomism.) Functional theories that recognize no content-determining external relata have been called solipsistic (Harman 1987). Some theorists posit distinct roles for internal and external connections, the former determining semantic properties analogous to sense, the latter determining semantic properties analogous to reference (McGinn 1982, Sterelny 1989)

(Reductive) representationalists (Dretske, Lycan, Tye) usually take one or another of these theories to provide an explanation of the (Non-conceptual) content of experiential states. They thus tend to be Externalists, about phenomenological as well as conceptual content. Phenomenalists and non-deductive representationalists (Block, Chalmers, Loar, Peacocke, Siewert), on the other hand, take it that the representational content of such states is (at least in part) determined by their intrinsic phenomenal properties. Further, those who advocate a phenomenology-based approach to conceptual content (Horgan and Tiensen, Loar, Pitt, Searle, Siewert) also seem to be committed to Internalist individuation of the content (if not the reference) of such states.

Generally, those who, like informational theorists, think relations to one's (natural or social) environment are (at least partially) determinative of the content of mental representations are Externalists (e.g., Burge 1979, 1986, McGinn 1977, Putnam 1975), whereas those who, like some proponents of functional theories, think representational content is determined by an individual's intrinsic properties alone, are internalists (or individualists).

This issue is widely taken to be of central importance, since psychological explanation, whether commonsense or scientific, is supposed to be both causal and content-based. (Beliefs and desires cause the behaviours they do because they have the contents they do. For example, the desire that one have a beer and the beliefs that there is beer in the refrigerator and that the refrigerator is in the kitchen may explain one's getting up and going to the kitchen.) If, however, a mental representation's having a particular content is due to factors extrinsic to it, it is unclear how its having that content could determine its causal powers, which, arguably, must be intrinsic. Some who accept the standard arguments for externalism have argued that internal factors determine a component of the content of a mental representation. They say that mental representations have both 'narrow' content (determined by intrinsic factors) and 'wide' or 'broad' content (determined by narrow content plus extrinsic factors). (This distinction may be applied to the sub-personal representations of cognitive science as well as to those of commonsense psychology.

Narrow content has been variously construed. Putnam (1975), Fodor (1982)), and Block (1986) for example, seems to understand it as something like dedictorial content (i.e., Frégean sense, or perhaps character, à la Kaplan 1989). On this construal, narrow content is context-independent and directly expressible. Fodor (1987) and Block (1986), however, has also characterized narrow content as radically inexpressible. On this construal, narrow content is a kind of proto-content, or content-determinant, and can be specified only indirectly, via specifications of context/wide-content pairings. Both, construe of as a narrow content and are characterized as functions from context to (wide) content. The narrow content of a representation is determined by properties intrinsic to it or its possessor such as its syntactic structure or its intra-mental computational or inferential role or its phenomenology.

Burge (1986) has argued that causation-based worries about externalist individuation of psychological content, and the introduction of the narrow notion, are misguided. Fodor (1994, 1998) has more recently urged that there may be no need to narrow its contentual representations, accountable for reasons of an ordering supply of naturalistic (causal) explanations of human cognition and action, since the sorts of cases they were introduced to handle, viz., Twin-Earth cases and Frége cases, are nomologically either impossible or dismissible as exceptions to non-strict psychological laws.

The leading contemporary version of the Representational Theory of Mind, the Computational Theory of Mind, claims that the brain is a kind of computer and that mental processes are computations. According to the computational theory of mind, cognitive states are constituted by computational relations to mental representations of various kinds, and cognitive processes are sequences of such states. The computational theory of mind and the representational theory of mind, may by attempting to explain all psychological states and processes in terms of mental representation. In the course of constructing detailed empirical theories of human and animal cognition and developing models of cognitive processes' implementable in artificial information processing systems, cognitive scientists have proposed a variety of types of mental representations. While some of these may be suited to be mental relata of commonsense psychological states, some - so-called 'subpersonal' or 'sub-doxastic' representations - are not. Though many philosophers believe that computational theory of mind can provide the best scientific explanations of cognition and behaviour, there is disagreement over whether such explanations will vindicate the commonsense psychological explanations of prescientific representational theory of mind.

According to Stich's (1983) Syntactic Theory of Mind, for example, computational theories of psychological states should concern themselves only with the formal properties of the objects those states are relations to. Commitment to the explanatory relevance of content, however, is for most cognitive scientists fundamental. That mental processes are computations, which computations are rule-governed sequences of semantically evaluable objects, and that the rules apply to the symbols in virtue of their content, are central tenets of mainstream cognitive science.

Explanations in cognitive science appeal to a many different kinds of mental representation, including, for example, the 'mental models' of Johnson-Laird 1983, the 'retinal arrays,' 'primal sketches' and '2½ -D sketches' of Marr 1982, the 'frames' of Minsky 1974, the 'sub-symbolic' structures of Smolensky 1989, the 'quasi-pictures' of Kosslyn 1980, and the 'interpreted symbol-filled arrays' of Tye 1991 - in addition to representations that may be appropriate to the explanation of commonsense

Psychological states. Computational explanations have been offered of, among other mental phenomena, belief.

The classicists hold that mental representations are symbolic structures, which typically have semantically evaluable constituents, and that mental processes are rule-governed manipulations of them that are sensitive to their constituent structure. The connectionists, hold that mental representations are realized by patterns of activation in a network of simple processors ('nodes') and that mental processes consist of the spreading activation of such patterns. The nodes themselves are, typically, not taken to be semantically evaluable; nor do the patterns have semantically evaluable constituents. (Though there are versions of Connectionism -, 'localist' versions - on which individual nodes are taken to have semantic properties (e.g., Ballard 1986, Ballard & Hayes 1984).) It is arguable, however, that localist theories are neither definitive nor representative of the Conceptionist program.

Classicists are motivated (in part) by properties thought seems to share with language. Jerry Alan Fodor's (1935-), Language of Thought Hypothesis, (Fodor 1975, 1987), according to which the system of mental symbols constituting the neural basis of thought is structured like a language, provides a well-worked-out version of the classical approach as applied to commonsense psychology. According to the language of a thought hypothesis, the potential infinity of complex representational mental states is generated from a finite stock of primitive representational states, in accordance with recursive formation rules. This combinatorial structure accounts for the properties of productivity and systematicity of the system of mental representations. As in the case of symbolic languages, including natural languages (though Fodor does not suppose either that the language of thought hypotheses explains only linguistic capacities or that only verbal creatures have this sort of cognitive architecture), these properties of thought are explained by appeal to the content of the representational units and their combinability into contentful complexes. That is, the semantics of both language and thought is compositional: the content of a complex representation is determined by the contents of its constituents and their structural configuration.

Connectionists are motivated mainly by a consideration of the architecture of the brain, which apparently consists of layered networks of interconnected neurons. They argue that this sort of architecture is unsuited to carrying out classical serial computations. For one thing, processing in the brain is typically massively parallel. In addition, the elements whose manipulation drive's computation in Conceptionist networks (principally, the connections between nodes) are neither semantically compositional nor semantically evaluable, as they are on the classical approach. This contrast with classical computationalism is often characterized by saying that representation is, with respect to computation, distributed as opposed to local: representation is local if it is computationally basic; and distributed if it is not. (Another way of putting this is to say that for classicists mental representations are computationally atomic, whereas for connectionists they are not.)

Moreover, connectionists argue that information processing as it occurs in Conceptionist networks more closely resembles some features of actual human cognitive functioning. For example, whereas on the classical view learning involves something like hypothesis formation and testing (Fodor 1981), on the Conceptionist model it is a matter of evolving distribution of 'weight' (strength) on the connections between nodes, and typically does not involve the formulation of hypotheses regarding the identity conditions for the objects of knowledge. The Conceptionist network is 'trained up' by repeated exposure to the objects it is to learn to distinguish; and, though networks typically require many more exposures to the objects than do humans, this seems to model at least one feature of this type of human learning quite well.

Further, degradation in the performance of such networks in response to damage is gradual, not sudden as in the case of a classical information processor, and hence more accurately models the loss of human cognitive function as it typically occurs in response to brain damage. It is also sometimes claimed that Conceptionist systems show the kind of flexibility in response to novel situations typical of human cognition - situations in which classical systems are relatively 'brittle' or 'fragile.'

Some philosophers have maintained that Connectionism entails that there are no propositional attitudes. Ramsey, Stich and Garon (1990) have argued that if Conceptionist models of cognition are basically correct, then there are no discrete representational states as conceived in ordinary commonsense psychology and classical cognitive science. Others, however (e.g., Smolensky 1989), hold that certain types of higher-level patterns of activity in a neural network may be roughly identified with the representational states of commonsense psychology. Still others argue that language-of-thought style representation is both necessary in general and realizable within Conceptionist architectures, collect the central contemporary papers in the classicist/Conceptionist debate, and provides useful introductory material as well.

Whereas Stich (1983) accepts that mental processes are computational, but denies that computations are sequences of mental representations, others accept the notion of mental representation, but deny that computational theory of mind provides the correct account of mental states and processes.

Van Gelder (1995) denies that psychological processes are computational. He argues that cognitive systems are dynamic, and that cognitive states are not relations to mental symbols, but quantifiable states of a complex system consisting of (in the case of human beings) a nervous system, a body and the environment in which they are embedded. Cognitive processes are not rule-governed sequences of discrete symbolic states, but continuous, evolving total states of dynamic systems determined by continuous, simultaneous and mutually determining states of the systems components. Representation in a dynamic system is essentially information-theoretic, though the bearers of information are not symbols, but state variables or parameters.

Horst (1996), on the other hand, argues that though computational models may be useful in scientific psychology, they are of no help in achieving a philosophical understanding of the intentionality of commonsense mental states. Computational theory of mind attempts to reduce the intentionality of such states to the intentionality of the mental symbols they are relations to. But, Horst claims, the relevant notion of symbolic content is essentially bound up with the notions of convention and intention. So the computational theory of mind involves itself in a vicious circularity: the very properties that are supposed to be reduced are (tacitly) appealed to in the reduction.

To say that a mental object has semantic properties is, paradigmatically, to say that it may be about, or be true or false of, an object or objects, or that it may be true or false simpliciter. Suppose I think that you took to sniffing snuff. I am thinking about you, and if what I think of you (that they take snuff) is true of you, then my thought is true. According to representational theory of mind such states are to be explained as relations between agents and mental representations. To think that you take snuff is to token in some way a mental representation whose content is that ocelots take snuff. On this view, the semantic properties of mental states are the semantic properties of the representations they are relations to.

Linguistic acts seem to share such properties with mental states. Suppose I say that you take snuff. I am talking about you, and if what I say of you (that they take snuff) is true of them, then my utterance is true. Now, to say that you take snuff is (in part) to utter a sentence that means that you take snuff. Many philosophers have thought that the semantic properties of linguistic expressions are inherited from the intentional mental states they are conventionally used to express. On this view, the semantic properties of linguistic expressions are the semantic properties of the representations that are the mental relata of the states they are conventionally used to express.

It is also widely held that in addition to having such properties as reference, truth-conditions and truth - so-called extensional properties - expressions of natural languages also have intensional properties, in virtue of expressing properties or propositions - i.e., in virtue of having meanings or senses, where two expressions may have the same reference, truth-conditions or truth value, yet express different properties or propositions (Frége 1892/1997). If the semantic properties of natural-language expressions are inherited from the thoughts and concepts they express (or vice versa, or both), then an analogous distinction may be appropriate for mental representations.

Theories of representational content may be classified according to whether they are atomistic or holistic and according to whether they are externalistic or internalistic, whereby, emphasizing the priority of a whole over its parts. Furthermore, in the philosophy of language, this becomes the claim that the meaning of an individual word or sentence can only be understood in terms of its relation to an indefinitely larger body of language, such as à whole theory, or even a whole language or form of life. In the philosophy of mind a mental state similarly may be identified only in terms of its relations with others. Moderate holism may allow the other things besides these relationships also count; extreme holism would hold that a network of relationships is all that we have. A holistic view of science holds that experience only confirms or disconfirms large bodies of doctrine, impinging at the edges, and leaving some leeway over the adjustment that it requires.

Once, again, in the philosophy of mind and language, the view that what is thought, or said, or experienced, is essentially dependent on aspects of the world external to the mind of the subject. The view goes beyond holding that such mental states are typically caused by external factors, to insist that they could not have existed as they now do without the subject being embedded in an external world of a certain kind. It is these external relations that make up the essence or identify of the mental state. Externalism is thus opposed to the Cartesian separation of the mental from the physical, since that holds that the mental could in principle exist as it does even if there were no external world at all. Various external factors have been advanced as ones on which mental content depends, including the usage of experts, the linguistic, norms of the community. And the general causal relationships of the subject. In the theory of knowledge, externalism is the view that a person might know something by being suitably situated with respect to it, without that relationship being in any sense within his purview. The person might, for example, be very reliable in some respect without believing that he is. The view allows that you can know without being justified in believing that you know.

However, atomistic theories take a representation's content to be something that can be specified independent entity of that representation' s relations to other representations. What the American philosopher of mind, Jerry Alan Fodor (1935-) calls the crude causal theory, for example, takes a representation to be a
cow
- a menial representation with the same content as the word 'cow' - if its tokens are caused by instantiations of the property of being-a-cow, and this is a condition that places no explicit constraints on how
cow
's must or might relate to other representations. Holistic theories contrasted with atomistic theories in taking the relations à representation bears to others to be essential to its content. According to functional role theories, a representation is a
cow
if it behaves like a
cow
should behave in inference.

Internalist theories take the content of a representation to be a matter determined by factors internal to the system that uses it. Thus, what Block (1986) calls 'short-armed' functional role theories are Internalist. Externalist theories take the content of a representation to be determined, in part at least, by factors external to the system that uses it. Covariance theories, as well as telelogical theories that invoke an historical theory of functions, take content to be determined by 'external' factors. Crossing the atomist-holistic distinction with the Internalist-externalist distinction.

Externalist theories (sometimes called non-individualistic theories) have the consequence that molecule for molecule identical cognitive systems might yet harbour representations with different contents. This has given rise to a controversy concerning 'narrow' content. If we assume some form of externalist theory is correct, then content is, in the first instance 'wide' content, i.e., determined in part by factors external to the representing system. On the other hand, it seems clear that, on plausible assumptions about how to individuate psychological capacities, internally equivalent systems must have the same psychological capacities. Hence, it would appear that wide content cannot be relevant to characterizing psychological equivalence. Since cognitive science generally assumes that content is relevant to characterizing psychological equivalence, philosophers attracted to externalist theories of content have sometimes attempted to introduce 'narrow' content, i.e., an aspect or kind of content that is equivalent internally equivalent systems. The simplest such theory is Fodor's idea (1987) that narrow content is a function from contents (i.e., from whatever the external factors are) to wide contents.

All the same, what a person expresses by a sentence is often a function of the environment in which he or she is placed. For example, the disease I refer to by the term like 'arthritis', or the kind of tree I refer to as a 'Maple' will be defined by criteria of which I know next to nothing. This raises the possibility of imagining two persons in rather different environments, but in which everything appears the same to each of them. The wide content of their thoughts and sayings will be different if the situation surrounding them is appropriately different: 'situation' may include the actual objects they perceive or the chemical or physical kinds of object in the world they inhabit, or the history of their words, or the decisions of authorities on what counts as an example, of one of the terms they use. The narrow content is that part of their thought which remains identical, through their identity of the way things appear, regardless of these differences of surroundings. Partisans of wide content may doubt whether any content in this sense narrow, partisans of narrow content believer that it is the fundamental notion, with wide content being explicable in terms of narrow content plus context.

Even so, the distinction between facts and values has outgrown its name: it applies not only to matters of fact vs, matters of value, but also to statements that something is, vs. statements that something ought to be. Roughly, factual statements - 'is statements' in the relevant sense - represent some state of affairs as obtaining, whereas normative statements - evaluative, and deontic ones - attribute goodness to something, or ascribe, to an agent, an obligation to act. Neither distinction is merely linguistic. Specifying a book's monetary value is making a factual statement, though it attributes a kind of value. 'That is a good book' expresses a value judgement though the term 'value' is absent (nor would 'valuable' be synonymous with 'good'). Similarly, 'we are morally obligated to fight' superficially expresses a statement, and 'By all indications it ough to rain' makes a kind of ought-claim; but the former is an ought-statement, the latter an (epistemic) is-statement.

Theoretical difficulties also beset the distinction. Some have absorbed values into facts holding that all value is instrumental, roughly, to have value is to contribute - in a factual analysable way - to something further which is (say) deemed desirable. Others have suffused facts with values, arguing that facts (and observations) are 'theory-impregnated' and contending that values are inescapable to theoretical choice. But while some philosophers doubt that fact/value distinctions can be sustained, there persists a sense of a deep difference between evaluating, and attributing an obligation and, on the other hand, saying how the world is.

Fact/value distinctions, may be defended by appeal to the notion of intrinsic value, as a thing has in itself and thus independently of its consequences. Roughly, a value statement (proper) is an ascription of intrinsic value, one to the effect that a thing is to some degree good in itself. This leaves open whether ought-statements are implicitly value statements, but even if they imply that something has intrinsic value - e.g., moral value - they can be independently characterized, say by appeal to rules that provide (justifying) reasons for action. One might also ground the fact value distinction in the attributional (or even motivational) component apparently implied by the making of valuational or deontic judgements: Thus, 'it is a good book, but that is no reason for a positive attribute towards it' and 'you ought to do it, but there is no reason to' seem inadmissible, whereas, substituting, 'an expensive book' and 'you will do it' yields permissible judgements. One might also argue that factual judgements are the kind which are in principle appraisable scientifically, and thereby anchor the distinction on the factual side. This ligne is plausible, but there is controversy over whether scientific procedures are 'value-free' in the required way.

Philosophers differ regarding the sense, if any, in which epistemology is normative (roughly, valuational). But what precisely is at stake in this controversy is no clearly than the problematic fact/value distinction itself. Must epistemologists as such make judgements of value or epistemic responsibility? If epistemology is naturalizable, then even epistemic principles simply articulate under what conditions - say, appropriate perceptual stimulations - a belief is justified, or constitutes knowledge. Its standards of justification, then would be like standards of, e.g., resilience for bridges. It is not obvious, however, that there appropriate standards can be established without independent judgements that, say, a certain kind of evidence is good enough for justified belief (or knowledge). The most plausible view may be that justification is like intrinsic goodness, though it supervenes on natural properties, it cannot be analysed wholly in factual statements.

Thus far, belief has been depicted as being all-or-nothing, however, as a resulting causality for which we have grounds for thinking it true, and, all the same, its acceptance is governed by epistemic norms, and, least of mention, it is partially subject to voluntary control and has functional affinities to belief. Still, the notion of acceptance, like that of degrees of belief, merely extends the standard picture, and does not replace it.

Traditionally, belief has been of epistemological interest in its propositional guise: 'S' believes that 'p', where 'p' is a reposition towards which an agent, 'S' exhibits an attitude of acceptance. Not all belief is of this sort. If I trust you to say, I believer you. And someone may believe in Mr. Radek, or in a free-market economy, or in God. It is sometimes supposed that all belief is 'reducible' to propositional belief, belief-that. Thus, my believing you might be thought a matter of my believing, is, perhaps, that what you say is true, and your belief in free markets or God, is a matter of your believing that free-market economies are desirable or that God exists.

Some philosophers have followed St. Thomas Aquinas (1225-74), in supposing that to believer in God is simply to believer that certain truths hold while others argue that belief-in is a distinctive attitude, on that includes essentially an element of trust. More commonly, belief-in has been taken to involve a combination of propositional belief together with some further attitude.

The moral philosopher Richard Price (1723-91) defends the claim that there are different sorts of belief-in, some, but not all reducible to beliefs-that. If you believer in God, you believer that God exists, that God is good, you believer that God is good, etc. But according to Price, your belief involves, in addition, a certain complex pro-attitude toward its object. Even so, belief-in outruns the evidence for the corresponding belief-that. Does this diminish its rationality? If belief-in presupposes believes-that, it might be thought that the evidential standards for the former must be, at least, as high as standards for the latter. And any additional pro-attitude might be thought to require a further layer of justification not required for cases of belief-that.

Belief-in may be, in general, less susceptible to alternations in the face of unfavourable evidence than belief-that. A believer who encounters evidence against God's existence may remain unshaken in his belief, in part because the evidence does not bear on his pro-attitude. So long as this ids united with his belief that God exists, and reasonably so - in a way that an ordinary propositional belief that would not.

The correlative way of elaborating on the general objection to justificatory externalism challenges the sufficiency of the various externalist conditions by citing cases where those conditions are satisfied, but where the believers in question seem intuitively not to be justified. In this context, the most widely discussed examples have to do with possible occult cognitive capacities, like clairvoyance. Considering the point in application once, again, to reliabilism, the claim is that to think that he has such a cognitive power, and, perhaps, even good reasons to the contrary, is not rational or responsible and therefore not epistemically justified in accepting the belief that result from his clairvoyance, dispite the fact that the reliablist condition is satisfied.

One sort of response to this latter sorts of an objection is to 'bite the bullet' and insist that such believers are in fact justified, dismissing the seeming intuitions to the contrary as latent Internalist prejudice. A more widely adopted response attempts to impose additional conditions, usually of a roughly Internalist sort, which will rule out the offending example, while stopping far of a full internalism. But, while there is little doubt that such modified versions of externalism can handle particular cases, as well enough to avoid clear intuitive implausibility, the usually problematic cases that they cannot handle, and also whether there is and clear motivation for the additional requirements other than the general Internalist view of justification that externalist is committed to reject.

A view in this same general vein, one that might be described as a hybrid of internalism and externalism holds that epistemic justification requires that there is a justificatial factor that is cognitively accessible to the believer in question (though it need not be actually grasped), thus ruling out, e.g., a pure reliabilism. At the same time, however, though it must be objectively true that beliefs for which such a factor is available are likely to be true, in addition, the fact need not be in any way grasped or cognitively accessible to the believer. In effect, of the premises needed to argue that a particular belief is likely to be true, one must be accessible in a way that would satisfy at least weak internalism, the Internalist will respond that this hybrid view is of no help at all in meeting the objection and has no belief nor is it held in the rational, responsible way that justification intuitively seems to require, for the believer in question, lacking one crucial premise, still has no reason at all for thinking that his belief is likely to be true.

An alternative to giving an externalist account of epistemic justification, one which may be more defensible while still accommodating many of the same motivating concerns, is to give an externalist account of knowledge directly, without relying on an intermediate account of justification. Such a view will obviously have to reject the justified true belief account of knowledge, holding instead that knowledge is true belief which satisfies the chosen externalist condition, e.g., a result of a reliable process (and perhaps, further conditions as well). This makes it possible for such a view to retain Internalist account of epistemic justification, though the centrality of that concept to epistemology would obviously be seriously diminished.

Such an externalist account of knowledge can accommodate the commonsense conviction that animals, young children, and unsophisticated adults' posse's knowledge, though not the weaker conviction (if such a conviction does exist) that such individuals are epistemically justified in their beliefs. It is, at least, less vulnerable to Internalist counter-examples of the sort discussed, since the intuitions involved there pertain more clearly to justification than to knowledge. What is uncertain is what ultimate philosophical significance the resulting conception of knowledge, for which is accepted or advanced as true or real on the basis of less than conclusive evidence, as can only be assumed to have. In particular, does it have any serious bearing on traditional epistemological problems and on the deepest and most troubling versions of scepticism, which seems in fact to be primarily concerned with justification, and knowledge?`

A rather different use of the terms 'internalism' and 'externalism' have to do with the issue of how the content of beliefs and thoughts is determined: According to an Internalist view of content, the content of such intention states depends only on the non-relational, internal properties of the individual's mind or grain, and not at all on his physical and social environment: While according to an externalist view, content is significantly affected by such external factors and suggests a view that appears of both internal and external elements are standardly classified as an external view.

As with justification and knowledge, the traditional view of content has been strongly Internalist in character. The main argument for externalism derives from the philosophy y of language, more specifically from the various phenomena pertaining to natural kind terms, indexicals, etc. that motivate the views that have come to be known as 'direct reference' theories. Such phenomena seem at least to show that the belief or thought content that can be properly attributed to a person is dependant on facts about his environment, e.g., whether he is on Earth or Twin Earth, what is fact pointing at, the classificatory criterion employed by expects in his social group, etc. - not just on what is going on internally in his mind or brain.

An objection to externalist account of content is that they seem unable to do justice to our ability to know the content of our beliefs or thought 'from the inside', simply by reflection. If content is depending on external factors pertaining to the environment, then knowledge of content should depend on knowledge of these factors - which will not in general be available to the person whose belief or thought is in question.

The adoption of an externalist account of mental content would seem to support an externalist account of justification, apart from all contentful representation is a belief inaccessible to the believer, then both the justifying statuses of other beliefs in relation to that of the same representation are the status of that content, being totally rationalized by further beliefs for which it will be similarly inaccessible. Thus, contravening the Internalist requirement for justification, as an Internalist must insist that there are no justification relations of these sorts, that our internally associable content can also not be warranted or as stated or indicated without the deviated departure from a course or procedure or from a norm or standard in showing no deviation from traditionally held methods of justification exacting by anything else: But such a response appears lame unless it is coupled with an attempt to show that the externalised account of content is mistaken.

Except for alleged cases of thing s that are evident for one just by being true, it has often been thought, anything is known must satisfy certain criteria as well as being true. Except for alleged cases of self-evident truths, it is often thought that anything that is known must satisfy certain criteria or standards. These criteria are general principles that will make a proposition evident or just make accepting it warranted to some degree. Common suggestions for this role include position ‘p’, e.g., that 2 + 2 = 4, ‘p’ is evident or, if ‘p’ coheres wit h the bulk of one’s beliefs, ‘p’ is warranted. These might be criteria whereby putative self-evident truths, e.g., that one clearly and distinctly conceive s ‘p’, ‘transmit’ the status as evident they already have without criteria to other proposition s like ‘p’, or they might be criteria whereby purely non-epistemic considerations, e.g., facts about logical connections or about conception that need not be already evident or warranted, originally ‘create’ p’s epistemic status. If that in turn can be ‘transmitted’ to other propositions, e.g., by deduction or induction, there will be criteria specifying when it is.

Nonetheless, of or relating to tradition a being previously characterized or specified to convey an idea indirectly, as an idea or theory for consideration and being so extreme a design or quality and lean towards an ecocatorial suggestion that implicate an involving responsibility that include: (1) if a proposition ‘p’, e.g., that 2 + 2 = 4, is clearly and distinctly conceived, then ‘p’ is evident, or simply, (2) if we can’t conceive ‘p’ to be false, then ‘p’ is evident: Or, (3) whenever are immediately conscious o f in thought or experience, e.g,, that we seem to see red, is evident. These might be criteria whereby putative self-evident truth s, e.g., that one clearly and distinctly conceives, e.g., that one clearly and distinctly conceives ‘p’, ‘transmit’ the status as evident they already have for one without criteria to other propositions like ‘p’. Alternatively, they might be criteria whereby epistemic status, e.g., p’s being evident, is originally created by purely non-epistemic considerations, e.g., facts about how ‘p’ is conceived which are neither self-evident is already criterial evident.

The result effect, holds that traditional criteria do not seem to make evident propositions about anything beyond our own thoughts, experiences and necessary truths, to which deductive or inductive criteria ma y be applied. Moreover, arguably, inductive criteria, including criteria warranting the best explanation of data, never make things evident or warrant their acceptance enough to count as knowledge.

Contemporary epistemologists suggest that traditional criteria may need alteration in three ways. Additional evidence may subject even our most basic judgements to rational correction, though they count as evident on the basis of our criteria. Warrant may be transmitted other than through deductive and inductive relations between propositions. Transmission criteria might not simply ‘pass’ evidence on linearly from a foundation of highly evident ‘premisses’ to ‘conclusions’ that are never more evident.

A group of statements, some of which purportedly provide support for another. The statements which purportedly provide the support are the premisses while the statement purportedly support is the conclusion. Arguments are typically divided into two categories depending on the degree of support they purportedly provide. Deductive arguments purportedly provide conclusive support for their conclusions while inductively supports the purported provision that inductive arguments purportedly provided only arguments purportedly in the providing probably of support. Some, but not all, arguments succeed in providing support for their conclusions. Successful deductive arguments are valid while successful inductive arguments are valid while successful inductive arguments are strong. An argument is valid just in case if all its premisses are true its conclusion is only probably true. Deductive logic provides methods for ascertaining whether or not an argument is valid whereas, inductive logic provides methods for ascertaining the degree of support the premisses of an argument confer on its conclusion.

Finally, proof, least of mention, is a collection of considerations and reasons that instill and sustain conviction that some proposed theorem - the theorem proved - is not only true, but could not possibly be false. A perceptual observation may instill the conviction that water is cold. But a proof that 2 + 5 = 5 must not only instill the conviction that is true that 2 + 3 = 5, but also that 2 + 3 could not be anything but 5.

No one has succeeded in replacing this largely psychological characterization of proofs by a more objective characterization. The representations of reconstructions of proofs as mechanical and semiotical derivation in formal-logical systems all but completely fail to capture ‘proofs’ as mathematicians are quite content to give them. For example, formal-logical derivations depend solely on the logical form of the considered proposition, whereas usually proofs depend in large measure on content of propositions other than their logical form.

Many concerns and disputed clusters around the idea associated with the term substance. The substance of a thing may be considered in: (1) Its essence, or that which makes it what it is. This will ensure that the substance of a thing is that which remains through change in properties. Again, in Aristotle, this essence becomes more than just the matter, but a unity of matter and form. (2) That which can exist by itself, or does not need a subject for existence, in the way that properties need objects, hence (3) that which bears properties, as a substance is then the subject of predication, that about which things are said as opposed to the things said about it. Substance in the last two senses stands opposed to modifications such as quantity, quality, relations, etc. it is hard to keep this set of ideas distinct from the doubtful notion of a substratum, something distinct from any of its properties, and hence, as an incapable characterization. The notion of substances tend to disappear in empiricist thought in fewer of the sensible questions of things with the notion of that in which they infer of giving way to an empirical notion of their regular occurrence. However, this is in turn is problematic, since it only makes sense to talk of the occurrence of an instance of qualities, not of quantities themselves. So the problem of what it is for a value quality to be the instance that remains.

Metaphysics inspired by modern science tends to reject the concept of substance in favours of concepts such as that of a field or a process, each of which may seem to provide a better example of a fundamental physical category.

It must be spoken of a concept that is deeply embedded in 18th century aesthetics, but deriving from the 1st century rhetorical treatise. On the Sublime, by Longinus. The sublime is great, fearful, noble, calculated to arouse sentiments of pride and majesty, as well as awe and sometimes terror. According to Alexander Gerards writing in 1759, When a large object is presented, the mind expands itself to the extent of that objects, and is filled with one grand sensation, which totally possessing it, composes it into a solemn sedateness and strikes it with deep silent wonder, and administration: It finds such a difficulty in spreading itself to the dimensions of its object, as enliven and invigorates which this occasions, it sometimes images itself present in every part of the sense which it contemplates, and from the sense of this immensity, feels a noble pride, and entertains a lofty conception of its own capacity.

In Kants aesthetic theory the sublime raises the soul above the height of vulgar complacency. We experience the vast spectacles of nature as absolutely great and of irresistible might and power. This perception is fearful, but by conquering this fear, and by regarding as small those things of which we are wont to be solicitous we quicken our sense of moral freedom. So we turn the experience of frailty and impotence into one of our true, inward moral freedom as the mind triumphs over nature, and it is this triumph of reason that is truly sublime. Kant thus paradoxically places our sense of the sublime in an awareness of ourselves as transcending nature, than in an awareness of ourselves as a frail and insignificant part of it.

Nevertheless, the doctrine that all relations are internal was a cardinal thesis of absolute idealism, and a central point of attack by the British philosophers George Edward Moore (1873-1958) and Bertrand Russell (1872-1970). It is a kind of essentialism, stating that if two things stand in some relationship, then they could not be what they are, did they not do so, if, for instance, I am wearing a hat mow, then when we imagine a possible situation that we would be got to describe as my not wearing the hat now, we would strictly not be imaging as one and the hat, but only some different individual.

The countering partitions a doctrine that bears some resemblance to the metaphysically based view of the German philosopher and mathematician Gottfried Leibniz (1646-1716) that if a person had any other attributes that the ones he has, he would not have been the same person. Leibniz thought that when asked that would have happened if Peter had not denied Christ. That being that if I am asking what had happened if Peter had not been Peter, denying Christ is contained in the complete notion of Peter. But he allowed that by the name Peter might be understood as what is involved in those attributes [of Peter] from which the denial does not follows. In order that we are held accountable to allow of external relations, in that these being relations which individuals could have or not depending upon contingent circumstances. The relations of ideas is used by the Scottish philosopher David Hume (1711-76) in the First Enquiry of Theoretical Knowledge. All the objects of human reason or enquiring naturally, be divided into two kinds: To unite all those, relations of ideas and matter of fact (Enquiry Concerning Human Understanding) the terms reflect the belief that any thing that can be known dependently must be internal to the mind, and hence transparent to us.

In Hume, objects of knowledge are divided into matter of fact (roughly empirical things known by means of impressions) and the relation of ideas. The contrast, also called Humes Fork, is a version of the speculative deductivity distinction, but reflects the 17th and early 18th centauries behind that the deductivity is established by chains of infinite certainty as comparable to ideas. It is extremely important that in the period between Descartes and J.S. Mill that a demonstration is not, but only a chain of intuitive comparable ideas, whereby a principle or maxim can be established by reason alone. It is in this sense that the English philosopher John Locke (1632-704) who believed that theological and moral principles are capable of demonstration, and Hume denies that they are, and also denies that scientific enquiries proceed in demonstrating its results.

A mathematical proof is formally inferred as to an argument that is used to show the truth of a mathematical assertion. In modern mathematics, a proof begins with one or more statements called premises and demonstrates, using the rules of logic, that if the premises are true then a particular conclusion must also be true.

The accepted methods and strategies used to construct a convincing mathematical argument have evolved since ancient times and continue to change. Consider the Pythagorean theorem, named after the 5th century Bc Greek mathematician and philosopher Pythagoras, which states that in a right-angled triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides. Many early civilizations considered this theorem true because it agreed with their observations in practical situations. But the early Greeks, among others, realized that observation and commonly held opinion do not guarantee mathematical truth. For example, before the 5th century Bc it was widely believed that all lengths could be expressed as the ratio of two whole numbers. But an unknown Greek mathematician proved that this was not true by showing that the length of the diagonal of a square with an area of 1 is the irrational number Ã.

The Greek mathematician Euclid laid down some of the conventions central to modern mathematical proofs. His book The Elements, written about 300 Bc, contains many proofs in the fields of geometry and algebra. This book illustrates the Greek practice of writing mathematical proofs by first clearly identifying the initial assumptions and then reasoning from them in a logical way in order to obtain a desired conclusion. As part of such an argument, Euclid used results that had already been shown to be true, called theorems, or statements that were explicitly acknowledged to be self-evident, called axioms; this practice continues today.

In the 20th century, proofs have been written that are so complex that no one person understands every argument used in them. In 1976, a computer was used to complete the proof of the four-colour theorem. This theorem states that four colours are sufficient to colour any map in such a way that regions with a common boundary ligne have different colours. The use of a computer in this proof inspired considerable debate in the mathematical community. At issue was whether a theorem can be considered proven if human beings have not actually checked every detail of the proof.

The study of the relations of deductibility among sentences in a logical calculus which benefits the proof theory. Deductibility is defined purely syntactically, that is, without reference to the intended interpretation of the calculus. The subject was founded by the mathematician David Hilbert (1862-1943) in the hope that strictly finitary methods would provide a way of proving the consistency of classical mathematics, but the ambition was torpedoed by Gödels second incompleteness theorem.

What is more, the use of a model to test for consistencies in an axiomatized system which is older than modern logic. Descartes algebraic interpretation of Euclidean geometry provides a way of showing that if the theory of real numbers is consistent, so is the geometry. Similar representation had been used by mathematicians in the 19th century, for example to show that if Euclidean geometry is consistent, so are various non-Euclidean geometries. Model theory is the general study of this kind of procedure: The proof theory studies relations of deductibility between formulae of a system, but once the notion of an interpretation is in place we can ask whether a formal system meets certain conditions. In particular, can it lead us from sentences that are true under some interpretation? And if a sentence is true under all interpretations, is it also a theorem of the system?

There are the questions of the soundness and completeness of a formal system. For the propositional calculus this turns into the question of whether the proof theory delivers as theorems all and only tautologies. There are many axiomatizations of the propositional calculus that are consistent and complete. The mathematical logician Kurt Gödel (1906-78) proved in 1929 that the first-order predicate under every interpretation is a theorem of the calculus. In that mathematical method for solving those physical problems that can be stated in the form that a certain value definite integral will have a stationary value for small changes of the functions in the integrands and of the limit of integration.

The Euclidean geometry is the greatest example of the pure axiomatic method, and as such had incalculable philosophical influence as a paradigm of rational certainty. It had no competition until the 19th century when it was realized that the fifth axiom of his system (parallel lines never meet) could be denied without inconsistency, leading to Riemannian spherical geometry. The significance of Riemannian geometry lies in its use and extension of both Euclidean geometry and the geometry of surfaces, leading to a number of generalized differential geometries. Its most important effect was that it made a geometrical application possible for some major abstractions of tensor analysis, leading to the pattern and concepts for general relativity later used by Albert Einstein in developing his theory of relativity. Riemannian geometry is also necessary for treating electricity and magnetism in the framework of general relativity. The fifth chapter of Euclid's Elements, is attributed to the mathematician Eudoxus, and contains a precise development of the real number, work which remained unappreciated until rediscovered in the 19th century.

The Axiom, in logic and mathematics, is a basic principle that is assumed to be true without proof. The use of axioms in mathematics stems from the ancient Greeks, most probably during the 5th century Bc, and represents the beginnings of pure mathematics as it is known today. Examples of axioms are the following: No sentence can be true and false at the same time (the principle of contradiction); If equals are added to equals, the sums are equal. The whole is greater than any of its parts. Logic and pure mathematics begin with such unproved assumptions from which other propositions (theorems) are derived. This procedure is necessary to avoid circularity, or an infinite regression in reasoning. The axioms of any system must be consistent with one another, that is, they should not lead to contradictions. They should be independent in the sense that they cannot be derived from one another. They should also be few in number. Axioms have sometimes been interpreted as self-evident truth. The present tendency is to avoid this claim and simply to assert that an axiom is assumed to be true without proof in the system of which it is a part.

The terms axiom and postulate are often used synonymously. Sometimes the word axiom is used to refer to basic principles that are assumed by every deductive system, and the term postulate is used to refer to first principles peculiar to a particular system, such as Euclidean geometry. Infrequently, the word axiom is used to refer to first principles in logic, and the term postulate is used to refer to first principles in mathematics.

The applications of game theory are wide-ranging and account for steadily growing interest in the subject. Von Neumann and Morgenstern indicated the immediate utility of their work on mathematical game theory in which may link it with economic behavior. Models can be developed, in fact, for markets of various commodities with differing numbers of buyers and sellers, fluctuating values of supply and demand, and seasonal and cyclical variations, as well as significant structural differences in the economies concerned. Here game theory is especially relevant to the analysis of conflicts of interest in maximizing profits and promoting the widest distribution of goods and services. Equitable division of property and of inheritance is another area of legal and economic concern that can be studied with the techniques of game theory.

In the social sciences, n-person game that has interesting uses in studying, for example, the distribution of power in legislative procedures. This problem can be interpreted as a three-person game at the congressional level involving vetoes of the president and votes of representatives and senators, analyzed in terms of successful or failed coalitions to pass a given bill. Problems of majority rule and individual decision making are also amenable to such study.

Sociologists have developed an entire branch of game that devoted to the study of issues involving group decision making. Epidemiologists also make use of game that, especially with respect to immunization procedures and methods of testing a vaccine or other medication. Military strategists turn to game that to study conflicts of interest resolved through battles where the outcome or payoff of a given war game is either victory or defeat. Usually, such games are not examples of zero-sum games, for what one player loses in terms of lives and injuries is not won by the victor. Some uses of game that in analyses of political and military events have been criticized as a dehumanizing and potentially dangerous oversimplification of necessarily complicating factors. Analysis of economic situations is also usually more complicated than zero-sum games because of the production of goods and services within the play of a given game.

All is the same in the classical that of the syllogism, a term in a categorical proposition is distributed if the proposition entails any proposition obtained from it by substituting a term denoted by the original. For example, in all dogs bark the term dogs is distributed, since it entails all terriers bark, which is obtained from it by a substitution. In Not all dogs bark, the same term is not distributed, since it may be true while not all terriers bark is false.

When a representation of one system by another is usually more familiar, in and for itself, that those extended in representation that their workings are supposed analogous to that of the first. This one might model the behavior of a sound wave upon that of waves in water, or the behavior of a gas upon that to a volume containing moving billiard balls. While nobody doubts that models have a useful heuristic role in science, there has been intense debate over whether a good model, or whether an organized structure of laws from which it can be deduced and suffices for scientific explanation. As such, the debate of topic was inaugurated by the French physicist Pierre Marie Maurice Duhem (1861-1916), in The Aim and Structure of Physical Thar (1954) by which Duhems conception of science is that it is simply a device for calculating as science provides deductive system that is systematic, economical, and predictive, but not that represents the deep underlying nature of reality. Steadfast and holding of its contributive thesis that in isolation, and since other auxiliary hypotheses will always be needed to draw empirical consequences from it. The Duhem thesis implies that refutation is a more complex matter than might appear. It is sometimes framed as the view that a single hypothesis may be retained in the face of any adverse empirical evidence, if we prepared to make modifications elsewhere in our system, although strictly speaking this is a stronger thesis, since it may be psychologically impossible to make consistent revisions in a belief system to accommodate, say, the hypothesis that there is a hippopotamus in the room when visibly there is not.

Primary and secondary qualities are the division associated with the 17th-century rise of modern science, wit h its recognition that the fundamental explanatory properties of things that are not the qualities that perception most immediately concerns. The latter are the secondary qualities, or immediate sensory qualities, including colour, taste, smell, felt warmth or texture, and sound. The primary properties are less tied to their deliverance of one particular sense, and include the size, shape, and motion of objects. In Robert Boyle (1627-92) and John Locke (1632-1704) the primary qualities are scientifically tractable, objective qualities essential to anything material, are of a minimal listing of size, shape, and mobility, i.e., the state of being at rest or moving. Locke sometimes adds number, solidity, texture (where this is thought of as the structure of a substance, or way in which it is made out of atoms). The secondary qualities are the powers to excite particular sensory modifications in observers. Once, again, that Locke himself thought in terms of identifying these powers with the texture of objects that, according to corpuscularian science of the time, were the basis of an objects causal capacities. The ideas of secondary qualities are sharply different from these powers, and afford us no accurate impression of them. For Renè Descartes (1596-1650), this is the basis for rejecting any attempt to think of knowledge of external objects as provided by the senses. But in Locke our ideas of primary qualities do afford us an accurate notion of what shape, size, and mobilities are. In English-speaking philosophy the first major discontent with the division was voiced by the Irish idealist George Berkeley (1685-1753), who probably took for a basis of his attack from Pierre Bayle (1647-1706), who in turn cites the French critic Simon Foucher (1644-96). Modern thought continues to wrestle with the difficulties of thinking of colour, taste, smell, warmth, and sound as real or objective properties to things independent of us.

Continuing as such, is the doctrine advocated by the American philosopher David Lewis (1941-2002), in that different possible worlds are to be thought of as existing exactly as this one does. Thinking in terms of possibilities is thinking of real worlds where things are different. The view has been charged with making it impossible to see why it is good to save the child from drowning, since there is still a possible world in which she (or her counterpart) drowned, and from the standpoint of the universe it should make no difference which world is actual. Critics also charge that the notion fails to fit either with current theory, if lf how we know about possible worlds, or with a current theory of why we are interested in them, but Lewis denied that any other way of interpreting modal statements is tenable.

The proposal set forth that characterizes the modality of a proposition as the notion for which it is true or false. The most important division is between propositions true of necessity, and those true as things are: Necessary as opposed to contingent propositions. Other qualifiers sometimes called modal include the tense indicators, it will be the case that p, or it was the case that p, and there are affinities between the deontic indicators, it ought to be the case that p, or it is permissible that p, and the of necessity and possibility.

The aim of a logic is to make explicit the rules by which inferences may be drawn, than to study the actual reasoning processes that people use, which may or may not conform to those rules. In the case of deductive logic, if we ask why we need to obey the rules, the most general form of answer is that if we do not we contradict ourselves (or, strictly speaking, we stand ready to contradict ourselves. Someone failing to draw a conclusion that follows from a set of premises need not be contradicting him or herself, but only failing to notice something. However, he or she is not defended against adding the contradictory conclusion to his or her set of beliefs.) There is no equally simple answer in the case of inductive logic, which is in general a less robust subject, but the aim will be to find reasoning such hat anyone failing to conform to it will have improbable beliefs. Traditional logic dominated the subject until the 19th century, and has become increasingly recognized in the 20th century, in that finer work that were done within that tradition, but syllogistic reasoning is now generally regarded as a limited special case of the form of reasoning that can be reprehend within the promotion and predated values, these form the heart of modern logic, as their central notions or qualifiers, variables, and functions were the creation of the German mathematician Gottlob Frége, who is recognized as the father of modern logic, although his treatment of a logical system as an abstract mathematical structure, or algebraic, has been heralded by the English mathematician and logician George Boole (1815-64), his pamphlet The Mathematical Analysis of Logic (1847) pioneered the algebra of classes. The work was made of in An Investigation of the Laws of Thought (1854). Boole also published several works in our mathematics, and on the that of probability. His name is remembered in the title of Boolean algebra, and the algebraic operations he investigated are denoted by Boolean operations.

The imparting information has been conduced or carried out of the prescribed procedures, as impeding of something that takes place in the chancing encounter out to be to enter oneness mind may from time to time occasion of various doctrines concerning the necessary properties; east of mention, by adding to a prepositional or predicated calculus two operator, □and ◊(sometimes written N and M), meaning necessarily and possible, respectfully. These like p ➞ ◊p and □p ➞ p will be wanted. Controversial these include □p ➞ □□p and ◊p ➞ □◊p. The classical modal theory for modal logic, due to the American logician and philosopher (1940-) and the Swedish logician Sig. Kanger, involves valuing prepositions not true or false simpiciter, but as true or false at possible worlds with necessity then corresponding to truth in all worlds, and possibility to truth in some world. Various different systems of modal logic result from adjusting the accessibility relation between worlds.

In Saul Kripke, gives the classical modern treatment of the topic of reference, both clarifying the distinction between names and definite description, and opening te door to many subsequent attempts to understand the notion of reference in terms of a causal link between the use of a term and an original episode of attaching a name to the subject.

One of the three branches into which semiotic is usually divided, the study of semantical meaning of words, and the relation of signs to the degree to which the designs are applicable. In that, in formal studies, a semantics is provided for a formal language when an interpretation of model is specified. However, a natural language comes ready interpreted, and the semantic problem is not that of specification but of understanding the relationship between terms of various categories (names, descriptions, predicate, adverbs . . . ) and their meaning. An influential proposal by attempting to provide a truth definition for the language, which will involve giving a full structure of different kinds have on the truth conditions of sentences containing them.

Holding that the basic case of reference is the relation between a name and the persons or object which it names. The philosophical problems include trying to elucidate that relation, to understand whether other semantic relations, such s that between a predicate and the property it expresses, or that between a description an what it describes, or that between myself and the word I, are examples of the same relation or of very different ones. A great deal of modern work on this was stimulated by the American logician Saul Kripkes, Naming and Necessity (1970). It would also be desirable to know whether we can refer to such things as objects and how to conduct the debate about each and issue. A popular approach, following Gottlob Frége, is to argue that the fundamental unit of analysis should be the whole sentence. The reference of a term becomes a derivative notion it is whatever it is that defines the terms contribution to the trued condition of the whole sentence. There need be nothing further to say about it, given that we have a way of understanding the attribution of meaning or truth-condition to sentences. Other approach, searching for a more substantive possibly that causality or psychological or social constituents are pronounced between words and things.

However, following Ramsey and the Italian mathematician G. Peano (1858-1932), it has been customary to distinguish logical paradoxes that depend upon a notion of reference or truth (semantic notions) such as those of the Liar family, Berry, Richard, etc. form the purely logical paradoxes in which no such notions are involved, such as Russells paradox, or those of Canto and Burali-Forti. Paradoxes of the first type seem to depend upon an element of self-reference, in which a sentence is about itself, or in which a phrase refers to something about itself, or in which a phrase refers to something defined by a set of phrases of which it is itself one. It is to feel that this element is responsible for the contradictions, although self-reference itself is often benign (for instance, the sentence All English sentences should have a verb, includes itself happily in the domain of sentences it is talking about), so the difficulty lies in forming a condition that existence only pathological self-reference. Paradoxes of the second kind then need a different treatment. Whilst the distinction is convenient, it allows for set theory to proceed by circumventing the latter paradoxes by technical mans, even when there is no solution to the semantic paradoxes, it may be a way of ignoring the similarities between the two families. There is still the possibility that while there is no agreed solution to the semantic paradoxes, our basis to understand of Russells Paradox may be imperfect as well.

Views about the meaning of terms will often depend on classifying the implicature of sayings involving the terms as implicatures or as genuine logical implications of what is said. Implicatures may be divided into two kinds: Conversational implicatures of the two kinds and the more subtle category of conventional implicatures. A term may as a matter of convention carries an implicature, thus one of the relations between he is poor and honest and he is poor but honest is that they have the same content (are true in just the same conditional) but the second has implicatures (that the combination is surprising or significant) that the first lacks.

It is, nonetheless, that we find in classical logic a proposition that may be true or false,. In that, if the former, it is said to take the truth-value true, and if the latter the truth-value false. The idea behind the terminological phrases is the analogues between assigning a propositional variable one or other of these values, as is done in providing an interpretation for a formula of the propositional calculus, and assigning an object as the value of any other variable. Logics with intermediate value are called many-valued logics.

Nevertheless, an existing definition of the predicate . . . is true for a language that satisfies convention T, the material adequately condition laid down by Alfred Tarski, born Alfred Teitelbaum (1901-83), whereby his methods of recursive definition, enabling us to say for each sentence what it is that its truth consists in, but giving no verbal definition of truth itself. The recursive definition or the truth predicate of a language is always provided in a metalanguage, Tarski is thus committed to a hierarchy of languages, each with it’s associated, but different truth-predicate. White this enables the approach to avoid the contradictions of paradoxical contemplations, it conflicts with the idea that a language should be able to say everything that there is to say, and other approaches have become increasingly important.

So, that the truth condition of a statement is the condition for which the world must meet if the statement is to be true. To know this condition is equivalent to knowing the meaning of the statement. Although this sounds as if it gives a solid anchorage for meaning, some of the securities disappear when it turns out that the truth condition can only be defined by repeating the very same statement: The truth condition of now is white is that snow is white, the truth condition of Britain would have capitulated had Hitler invaded, is that Britain would have capitulated had Hitler invaded. It is disputed whether this element of running-on-the-spot disqualifies truth conditions from playing the central role in a substantives theory of meaning. Truth-conditional theories of meaning are sometimes opposed by the view that to know the meaning of a statement is to be able to use it in a network of inferences.

Taken to be the view, inferential semantics take on the role of sentence in inference give a more important key to their meaning than this external relations to things in the world. The meaning of a sentence becomes its place in a network of inferences that it legitimates. Also known as functional role semantics, procedural semantics, or conception to the coherence theory of truth, and suffers from the same suspicion that it divorces meaning from any clarity association with things in the world.

Moreover, a theory of semantic truth be that of the view if language is provided with a truth definition, there is a sufficient characterization of its concept of truth, as there is no further philosophical chapter to write about truth: There is no further philosophical chapter to write about truth itself or truth as shared across different languages. The view is similar to the disquotational theory.

The redundancy theory, or also known as the deflationary view of truth fathered by Gottlob Frége and the Cambridge mathematician and philosopher Frank Ramsey (1903-30), who showed how the distinction between the semantic paradoxes, such as that of the Liar, and Russells paradox, made unnecessary the ramified type theory of Principia Mathematica, and the resulting axiom of reducibility. By taking all the sentences affirmed in a scientific theory that use some terms, e.g., quark, and to a considerable degree of replacing the term by a variable instead of saying that quarks have such-and-such properties, the Ramsey sentence says that there is something that has those properties. If the process is repeated for all of a group of the theoretical terms, the sentence gives topic-neutral structure of the theory, but removes any implication that we know what the terms so treated denote. It leaves open the possibility of identifying the theoretical item with whatever. It is that, the best fits the description provided. However, it was pointed out by the Cambridge mathematician Newman, that if the process is carried out for all except the logical of excavated fossils of a theory, then by the Löwenheim-Skolem theorem, the result will be interpretable, and the content of the theory may reasonably be felt to have been lost.

While, both Frége and Ramsey are agreeing that the essential claim is that the predicate . . . is true does not have a sense, i.e., expresses no substantive or profound or explanatory concept that ought to be the topic of philosophical enquiry. The approach admits of different versions, but centers on the points (1) that it is true that p says no more nor less than p (hence, redundancy): (2) that in less direct contexts, such as everything he said was true, or all logical consequences of true propositions are true, the predicate functions as a device enabling us to generalize than as an adjective or predicate describing the things he said, or the kinds of propositions that follow from true preposition. For example, the second may translate as: (∀p, q)(p & p ➞ q ➞ q) where there is no use of a notion of truth.

There are technical problems in interpreting all uses of the notion of truth in such ways, nevertheless, they are not generally felt to be insurmountable. The approach needs to explain away apparently substantive uses of the notion, such as science aims at the truth, or truth is a norm governing discourse. Postmodern writing frequently advocates that we must abandon such norms. Along with a discredited objective conception of truth. Perhaps, we can have the norms even when objectivity is problematic, since they can be framed without mention of truth: Science wants it to be so that whatever science holds that 'p', then 'p'. Discourse is to be regulated by the principle that it is wrong to assert 'p', when 'not-p'.

Something that tends of something in addition of content, or coming by way to justify such a position can very well be more that in addition to several reasons, as to bring in or joining of something might that there be more so as to a larger combination for us to consider the simplest of formulations, is that the claim that expression of the form ‘S’ is true mean the same as expression of the form ‘S’. Some philosophers dislike the ideas of sameness of meaning, and if this I disallowed, then the claim is that the two forms are equivalent in any sense of equivalence that matters. This is, it makes no difference whether people say Dogs bark is true, or whether they say, dogs bark. In the former representation of what they say of the sentence Dogs bark is mentioned, but in the later it appears to be used, of the claim that the two are equivalent and needs careful formulation and defence. On the face of it someone might know that Dogs bark is true without knowing what it means (for instance, if he kids in a list of acknowledged truth, although he does not understand English), and it is different from knowing that dogs bark. Disquotational theories are usually presented as versions of the redundancy theory of truth.

The relationship between a set of premises and a conclusion when the conclusion follows from the premise, many philosophers identify this with it being logically impossible that the premises should all be true, yet the conclusion false. Others are sufficiently impressed by the paradoxes of strict implication to look for a stranger relation, which would distinguish between valid and invalid arguments within the sphere of necessary propositions. The search for a strange notion is the field of relevance logic.

From a systematic theoretical point of view, we may imagine the process of evolution of an empirical science to be a continuous process of induction. Theories are evolved and are expressed in short encompassing as statements of as large number of individual observations in the form of empirical laws, from which the general laws can be ascertained by comparison. Regarded in this way, the development of a science bears some resemblance to the compilation of a classified catalogue. It is, a it were, a purely empirical enterprise.

But this point of view by no means embraces the whole of the actual process, it slurs over the important part played by intuition and deductive thought in the development of an exact science. As soon as a science has emerged from its initial stages, theoretical advances are no longer achieved merely by a process of arrangement. Guided by empirical data, the investigators rather develops a system of thought which, in general, it is built up logically from a small number of fundamental assumptions, the so-called axioms. We call such a system of thought a theory. The theory finds the justification for its existence in the fact that it correlates a large number of single observations, and is just here that the truth of the theory lies.

Corresponding to the same complex of empirical data, there may be several theories, which differ from one another to a considerable extent. But as regards the deductions from the theories which are capable of being tested, the agreement between the theories may be so complete, that it becomes difficult to find any deductions in which the theories differ from each other. As an example, a case of general interest is available in the province of biology, in the Darwinian theory of the development of species by selection in the struggle for existence, and in the theory of development which is based on the hypophysis of the hereditary transmission of acquired characters. The Origin of Species was principally successful in marshalling the evidence for evolution, than providing a convincing mechanisms for genetic change. And Darwin himself remained open to the search for additional mechanisms, while also remaining convinced that natural selection was at the hart of it. It was only with the later discovery of the gene as the unit of inheritance that the synthesis known as neo-Darwinism became the orthodox theory of evolution in the life sciences.

In the 19th century the attempt to base ethical reasoning o the presumed facts about evolution, the movement is particularly associated with the English philosopher of evolution Herbert Spencer (1820-1903). The premise is that later elements in an evolutionary path are better than earlier ones: The application of this principle then requires seeing western society, laissez-faire capitalism, or some other object of approval, as more evolved than more primitive social forms. Neither the principle nor the applications command much respect. The version of evolutionary ethics called social Darwinism emphasises the struggle for natural selection, and draws the conclusion that we should glorify and assist such struggle, usually by enhancing competition and aggressive relations between people in society or between evolution and ethics has been re-thought in the light of biological discoveries concerning altruism and kin-selection.

Once again, the psychology proving attempts are founded to evolutionary principles, in which a variety of higher mental functions may be adaptations, forced in response to selection pressures on the human populations through evolutionary time. Candidates for such theorizing include material and paternal motivations, capacities for love and friendship, the development of language as a signalling system cooperative and aggressive, our emotional repertoire, our moral and reactions, including the disposition to detect and punish those who cheat on agreements or whom free-ride on the work of others, our cognitive structures, and many others. Evolutionary psychology goes hand-in-hand with neurophysiological evidence about the underlying circuitry in the brain which subserves the psychological mechanisms it claims to identify. The approach was foreshadowed by Darwin himself, and William James, as well as the sociology of E.O. Wilson. The designated uses are applied, more or less aggressively, especially to explanations offered in sociobiology and evolutionary psychology.

Another assumption that is frequently used to legitimate the real existence of forces associated with the invisible hand in neoclassical economics derives from Darwins view of natural selection as a war-like competing between atomized organisms in the struggle for survival. In natural selection as we now understand it, cooperation appears to exist in complementary relation to competition. Complementary relationships between such results are emergent self-regulating properties that are greater than the sum of parts and that serve to perpetuate the existence of the whole.

According to E.O. Wilson, the human mind evolved to believe in the gods’ and people need a sacred narrative to have a sense of higher purpose. Yet, it is also clear that the gods’ in his view are merely human constructs and, therefore, there is no basis for dialogue between the world-view of science and religion. Science for its part, said Wilson, will test relentlessly every assumption about the human condition and in time uncover the bedrock of the moral an religious sentiment. The eventual result of the competition between the other, will be the secularization of the human epic and of religion itself.

Man has come to the threshold of a state of consciousness, regarding his nature and his relationship to te Cosmos, in terms that reflect reality. By using the processes of nature as metaphor, to describe the forces by which it operates upon and within Man, we come as close to describing reality as we can within the limits of our comprehension. Men will be very uneven in their capacity for such understanding, which, naturally, differs for different ages and cultures, and develops and changes over the course of time. For these reasons it will always be necessary to use metaphor and myth to provide comprehensible guides to living. In thus way. Mans imagination and intellect play vital roles on his survival and evolution.

Since so much of life both inside and outside the study is concerned with finding explanations of things, it would be desirable to have a concept of what counts as a good explanation from bad. Under the influence of logical positivist approaches to the structure of science, it was felt that the criterion ought to be found in a definite logical relationship between the exlanans (that which does the explaining) and the explanandum (that which is to be explained). The approach culminated in the covering law model of explanation, or the view that an event is explained when it is subsumed under a law of nature, that is, its occurrence is deducible from the law plus a set of initial conditions. A law would itself be explained by being deduced from a higher-order or covering law, in the way that Johannes Kepler(or, Keppler, 1571-1630), was by way of planetary motion that the laws were deducible from Newtons laws of motion. The covering law model may be adapted to include explanation by showing that something is probable, given a statistical law. Questions for the covering law model include querying for the covering laws are necessary to explanation (we explain whether everyday events without overtly citing laws): Querying whether they are sufficient (it ma y not explain an event just to say that it is an example of the kind of thing that always happens). And querying whether a purely logical relationship is adapted to capturing the requirements, in that we fashion to explanations. These may include, for instance, that we have a feel for what is happening, or that the explanation proceeds in terms of things that are familiar to us or unsurprising, or that we can give a model of what is going on, and none of these notions is captured in a purely logical approach. Recent work, therefore, has tended to stress the contextual and pragmatic elements in requirements for explanation, so that what counts as good explanation given one set of concerns may not do so given another.

The argument to the best explanation is the view that once we can select the best of any in something in explanations of an event, then we are justified in accepting it, or even believing it. The principle needs qualification, since something it is unwise to ignore the antecedent improbability of a hypothesis which would explain the data better than others, e.g., the best explanation of a coin falling heads 530 times in 1,000 tosses might be that it is biased to give a probability of heads of 0.53 but it might be more sensible to suppose that it is fair, or to suspend judgement.

In a philosophy of language is considered as the general attempt to understand the components of a working language, the relationship with the understanding speaker has to its elements, and the relationship they bear to the world. The subject therefore embraces the traditional division of semiotic into syntax, semantics, an d pragmatics. The philosophy of language thus mingles with the philosophy of mind, since it needs an account of what it is in our understanding that enables us to use language. It so mingles with the metaphysics of truth and the relationship between sign and object. Much as much is that the philosophy in the 20th century, has been informed by the belief that philosophy of language is the fundamental basis of all philosophical problems, in that language is the distinctive exercise of mind, and the distinctive way in which we give shape to metaphysical beliefs. Particular topics will include the problems of logical form,. And the basis of the division between syntax and semantics, as well as problems of understanding the number and nature of specifically semantic relationships such as meaning, reference, predication, and quantification. Pragmatics include that of speech acts, while problems of rule following and the indeterminacy of translated infect philosophies of both pragmatics and semantics.

On this conception, to understand a sentence is to know its truth-conditions, and, yet, in a distinctive way the conception has remained central that those who offer opposing theories characteristically define their position by reference to it. The Conception of meanings truth-conditions need not and should not be advanced for being in itself as complete account of meaning. For instance, one who understands a language must have some idea of the range of speech acts contextually performed by the various types of sentences in the language, and must have some idea of the insufficiencies of various kinds of speech act. The claim of the theorist of truth-conditions should rather be targeted on the notion of content: If indicative sentences differ in what they strictly and literally say, then this difference is fully accounted for by the difference in the truth-conditions.

The meaning of a complex expression is a function of the meaning of its constituent. This is just as a sentence of what it is for an expression to be semantically complex. It is one of the initial attractions of the conception of meaning truth-conditions tat it permits a smooth and satisfying account of the way in which the meaning of s complex expression is a function of the meaning of its constituents. On the truth-conditional conception, to give the meaning of an expression is to state the contribution it makes to the truth-conditions of sentences in which it occurs. For singular terms - proper names, indexical, and certain pronouns - this is done by stating the reference of the terms in question. For predicates, it is done either by stating the conditions under which the predicate is true of arbitrary objects, or by stating that conditions under which arbitrary atomic sentences containing it is true. The meaning of a sentence-forming operator is given by stating its contribution to the truth-conditions of as complex sentence, as a function of the semantic values of the sentences on which it operates.

The theorist of truth conditions should insist that not every true statement about the reference of an expression is fit to be an axiom in a meaning-giving theory of truth for a language, such is the axiom: London refers to the city in which there was a huge fire in 1666, is a true statement about the reference of London. It is a consequent of a theory which substitutes this axiom for no different a term than of our simple truth theory that London is beautiful is true if and only if the city in which there was a huge fire in 1666 is beautiful. Since a subject can understand the name London without knowing that last-mentioned truth condition, this replacement axiom is not fit to be an axiom in a meaning specifies a truth theory. It is, of course, incumbent on a theorized meaning of truth conditions, to state in a way which does not presuppose any previous, non-truth conditional conception of meaning

Among the many challenges facing the theorist of truth conditions, two are particularly salient and fundamental. First, the theorist has to answer the charge of triviality or vacuity, second, the theorist must offer an account of what it is for a persons language to be truly describable by as semantic theory containing a given semantic axiom.

Since the content of a claim that the sentence Paris is beautiful is true amounts to a no more than the claim that Paris is beautiful, we can trivially describers understanding a sentence, if we wish, as knowing its truth-conditions, but this gives us no substantive account of understanding whatsoever. Something other than the grasp of truth conditions must provide the substantive account. The charge rests upon what has been called the redundancy theory of truth, the theory which, somewhat more discriminatingly. Horwich calls the minimal theory of truth. It’s conceptual representation that the concept of truth is exhausted by the fact that it conforms to the equivalence principle, the principle that for any proposition p, it is true that p if and only if p. Many different philosophical theories of truth will, with suitable qualifications, except that equivalence principle. The distinguishing feature of the minimal theory is its claim that the equivalence principle exhausts the notion of truth. It is now widely accepted, both by opponents and supporters of truth conditional theories of meaning, that it is inconsistent to accept both minimal theory of truth and a truth conditional account of meaning. If the claim that the sentence Paris is beautiful is true is exhausted by its equivalence to the claim that Paris is beautiful, it is circular to try of its truth conditions. The minimal theory of truth has been endorsed by the Cambridge mathematician and philosopher Plumpton Ramsey (1903-30), and the English philosopher Jules Ayer, the later Wittgenstein, Quine, Strawson. Horwich and - confusing and inconsistently if this article is correct - Frége himself. But is the minimal theory correct?

The minimal theory treats instances of the equivalence principle as definitional of truth for a given sentence, but in fact, it seems that each instance of the equivalence principle can itself be explained. The truth from which such an instance as: London is beautiful is true if and only if London is beautiful. This would be a pseudo-explanation if the fact that London refers to London consists in part in the fact that London is beautiful has the truth-condition it does. But it is very implausible, it is, after all, possible to understand the name London without understanding the predicate is beautiful.

Sometimes, however, the counterfactual conditional is known as 'subjunctive conditionals', insofar as a counterfactual conditional is a conditional of the form if 'p' were to happen 'q' would, or if 'p' were to have happened 'q' would have happened, where the supposition of 'p' is contrary to the known fact that 'not-p'. Such assertions are nevertheless, useful if you broke the bone, the X-ray would have looked different, or if the reactor were to fail, this mechanism would click into some important truths, even when we know that the bone is not broken or are certain that the reactor will not fail. It is arguably distinctive of laws of nature that yield counterfactuals (if the metal were to be heated, it would expand), whereas accidentally true generalizations may not. It is clear that counterfactuals cannot be represented by the material implication of the propositional calculus, since that conditionals come out true whenever ‘p’ is false, so there would be no division between true and false counterfactuals.

Although the subjunctive form indicates of some realizable counterfactual, in many contexts it does not seem to matter whether we use a subjunctive form, or a simple conditional form: If you run out of water, you will be in trouble seems equivalent to if you were to run out of water, you would be in trouble, in other contexts there is a big difference: If Oswald did not kill Kennedy, someone else did is clearly true, whereas if Oswald had not killed Kennedy, someone would have is most probably false.

The best-known modern treatment of counterfactuals is that of David Lewis, which evaluates them as true or false according to whether ‘q’ is true in the most similar possible worlds to ours in which ‘p’ is true. The similarity-ranking this approach needs have proved controversial, particularly since it may need to presuppose some notion of the same laws of nature, whereas art of the interest in counterfactuals is that they promise to illuminate that notion. There is a growing awareness tat the classification of conditionals is an extremely tricky business, and categorizing them as counterfactuals or not be of limited use.

The pronouncing of any conditional; Preposition of the form if 'p' then 'q'. The condition hypothesizes, 'p'. It’s called the antecedent of the conditional, and 'q' the consequent. Various kinds of conditional have been distinguished, weaken in that of material implication, merely telling us that with 'not-p'. or 'q', stronger conditionals include elements of modality, corresponding to the thought that if 'p' is true then 'q' must be true. Ordinary language is very flexible in its use of the conditional form, and there is controversy whether, yielding different kinds of conditionals with different meanings, or pragmatically, in which case there should be one basic meaning which case there should be one basic meaning, with surface differences arising from other implicatures.

We now turn to a philosophy of meaning and truth, under which it is especially associated with the American philosopher of science and of language (1839-1914), and the American psychologist philosopher William James (1842-1910), Wherefore the study in Pragmatism is given to various formulations by both writers, but the core is the belief that the meaning of a doctrine is the same as the practical effects of adapting it. Peirce interpreted of theocratical sentences is only that of a corresponding practical maxim (telling us what to do in some circumstance). In James position issues in a theory of truth, notoriously allowing that belief, including, for example, belief in God, are the widest sense of the works satisfactorially in the widest sense of the word. On James' view almost any belief might be respectable, and even rue, provided it works (but working is no simple matter for James). The apparently subjectivist consequences of this were wildly assailed by Russell (1872-1970), Moore (1873-1958), and others in the early years of the 20 century. This led to a division within pragmatism between those such as the American educator John Dewey (1859-1952), whose humanistic conception of practice remains inspired by science, and the more idealistic route that especially by the English writer F.C.S. Schiller (1864-1937), embracing the doctrine that our cognitive efforts and human needs actually transform the reality that we seek to describe. James often writes as if he sympathizes with this development. For instance, in The Meaning of Truth (1909), he considers the hypothesis that other people have no minds (dramatized in the sexist idea of an automatic sweetheart or female zombie) and remarks hat the hypothesis would not work because it would not satisfy our egoistic craving for the recognition and admiration of others. The implication that this is what makes it true that the other persons have minds in the disturbing part.

Modern pragmatists such as the American philosopher and critic Richard Rorty (1931-) and some writings of the philosopher Hilary Putnam (1925-) who have usually tried to dispense with an account of truth and concentrate, as perhaps James should have done, upon the nature of belief and its relations with human attitude, emotion, and need. The driving motivation of pragmatism is the idea that belief in the truth on te one hand must have a close connexion with success in action on the other. One way of cementing the connexion is found in the idea that natural selection must have adapted us to be cognitive creatures because belief have effects, as they work. Pragmatism can be found in Kants doctrine of the primary of practical over pure reason, and continued to play an influential role in the theory of meaning and of truth.

In case of fact, the philosophy of mind is the modern successor to behaviourism, as do the functionalism that its early advocates were Putnam (1926-) and Sellars (1912-89), and its guiding principle is that we can define mental states by a triplet of relations they have on other mental states, what effects they have on behavior. The definition need not take the form of a simple analysis, but if it were it could write down the totality of axioms, or postdate, or platitudes that govern our theories about what things of other mental states, and our theories about what things are apt to cause (for example), a belief state, what effects it would have on a variety of other mental states, and what affects it is likely to have on behavior, then we would have done all that is needed to make the state a proper theoretical notion. It could be implicitly defied by this, for which of Functionalism is often compared with descriptions of a computer, since according to mental descriptions correspond to a description of a machine in terms of software, that remains silent about the underlaying hardware or realization of the program the machine is running. The principal advantage of functionalism include its fit with the way we know of mental states both of ourselves and others, which is via their effects on behavior and other mental states. As with behaviourism, critics charge that structurally complex items that do not bear mental states might nevertheless, imitate the functions that are cited. According to this criticism functionalism is too generous and would count too many things as having minds. It is also queried whether functionalism is too paradoxical, able to see mental similarities only when there is causal similarity, when our actual practices of interpretations enable us to ascribe thoughts and desires to different from our own, it may then seem as though beliefs and desires can be variably realized causal architecture, just as much as they can be in different neurophysiological states.

The philosophical movement of Pragmatism had a major impact on American culture from the late 19th century to the present. Pragmatism calls for ideas and theories to be tested in practice, by assessing whether acting upon the idea or theory produces desirable or undesirable results. According to pragmatists, all claims about truth, knowledge, morality, and politics must be tested in this way. Pragmatism has been critical of traditional Western philosophy, especially the notion that there are absolute truth and absolute values. Although pragmatism was popular for a time in France, England, and Italy, most observers believe that it encapsulates an American faith in knowing how and the practicality is an equally American distrust of abstract theories and ideologies.

In mentioning the American psychologist and philosopher we find William James, who helped to popularize the philosophy of pragmatism with his book Pragmatism: A New Name for Old Ways of Thinking (1907). Influenced by a theory of meaning and verification developed for scientific hypotheses by American philosopher C. S. Peirce, James held that truth is what works, or has good experimental results. In a related theory, James argued the existence of God is partly verifiable because many people derive benefits from believing.

The Association for International Conciliation first published William James' pacifist statement, The Moral Equivalent of War, in 1910. James, a highly respected philosopher and psychologist, was one of the founders of pragmatism - a philosophical movement holding that ideas and theories must be tested in practice to assess their worth. James hoped to find a way to convince men with a long-standing history of pride and glory in war to evolve beyond the need for bloodshed and to develop other avenues for conflict resolution. Spelling and grammar represent standards of the time.

Pragmatists regard all theories and institutions as tentative hypotheses and solutions. For this reason they believed that efforts to improve society, through such means as education or politics, must be geared toward problem solving and must be ongoing. Through their emphasis on connecting theory to practice, pragmatist thinkers attempted to transform all areas of philosophy, from metaphysics to ethics and political philosophy.

Pragmatism sought a middle ground between traditional ideas about the nature of reality and radical theories of nihilism and irrationalism, which had become popular in Europe in the late 19th century. Traditional metaphysics assumed that the world has a fixed, intelligible structure and that human beings can know absolute or objective truth about the world and about what constitutes moral behavior. Nihilism and irrationalism, on the other hand, denied those very assumptions and their certitude. Pragmatists today still try to steer a middle course between contemporary offshoots of these two extremes.

The ideas of the pragmatists were considered revolutionary when they first appeared. To some critics, pragmatisms refusal to affirm any absolutes carried negative implications for society. For example, pragmatists do not believe that a single absolute idea of goodness or justice exists, but rather that these concepts are changeable and depend on the context in which they are being discussed. The absence of these absolutes, critics feared, could result in a decline in moral standards. The pragmatists denial of absolutes, moreover, challenged the foundations of religion, government, and schools of thought. As a result, pragmatism influenced developments in psychology, sociology, education, semiotics (the study of signs and symbols), and scientific method, as well as philosophy, cultural criticism, and social reform movements. Various political groups have also drawn on the assumptions of pragmatism, from the progressive movements of the early 20th century to later experiments in social reform.

Pragmatism is best understood in its historical and cultural context. It arose during the late 19th century, a period of rapid scientific advancement typified by the theories of British biologist Charles Darwin, whose theories suggested too many thinkers that humanity and society are in a perpetuated state of progress. During this same period a decline in traditional religious beliefs and values accompanied the industrialization and material progress of the time. In consequence it became necessary to rethink fundamental ideas about values, religion, science, community, and individuality.

The three most important pragmatists are American philosophers Charles Sanders Peirce, William James, and John Dewey. Peirce was primarily interested in scientific method and mathematics; his objective was to infuse scientific thinking into philosophy and society, and he believed that human comprehension of reality was becoming ever greater and that human communities were becoming increasingly progressive. Peirce developed pragmatism as a theory of meaning - in particular, the meaning of concepts used in science. The meaning of the concept 'brittle', for example, is given by the observed consequences or properties that objects called brittle exhibit. For Peirce, the only rational way to increase knowledge was to form mental habits that would test ideas through observation, experimentation, or what he called inquiry. Many philosophers known as logical positivists, a group of philosophers who have been influenced by Peirce, believed that our evolving species was fated to get ever closer to Truth. Logical positivists emphasize the importance of scientific verification, rejecting the assertion of positivism that personal experience is the basis of true knowledge.

James moved pragmatism in directions that Peirce strongly disliked. He generalized Peirces doctrines to encompass all concepts, beliefs, and actions; he also applied pragmatist ideas to truth as well as to meaning. James was primarily interested in showing how systems of morality, religion, and faith could be defended in a scientific civilization. He argued that sentiment, as well as logic, is crucial to rationality and that the great issues of life - morality and religious belief, for example - are leaps of faith. As such, they depend upon what he called the will to believe and not merely on scientific evidence, which can never tell us what to do or what is worthwhile. Critics charged James with relativism (the belief that values depend on specific situations) and with crass expediency for proposing that if an idea or action works the way one intends, it must be right. But James can more accurately be described as a pluralist - someone who believes the world to be far too complex for any-one philosophy to explain everything.

Deweys' philosophy can be described as a version of philosophical naturalism, which regards human experience, intelligence, and communities as ever-evolving mechanisms. Using their experience and intelligence, Dewey believed, human beings can solve problems, including social problems, through inquiry. For Dewey, naturalism led to the idea of a democratic society that allows all members to acquire social intelligence and progress both as individuals and as communities. Dewey held that traditional ideas about knowledge, truth, and values, in which absolutes are assumed, are incompatible with a broadly Darwinian world-view in which individuals and society are progressing. In consequence, he felt that these traditional ideas must be discarded or revised. Indeed, for pragmatists, everything people know and do depend on a historical context and is thus tentative rather than absolute.

Many followers and critics of Dewey believe he advocated elitism and social engineering in his philosophical stance. Others think of him as a kind of romantic humanist. Both tendencies are evident in Deweys writings, although he aspired to synthesize the two realms.

The pragmatists tradition was revitalized in the 1980s by American philosopher Richard Rorty, who has faced similar charges of elitism for his belief in the relativism of values and his emphasis on the role of the individual in attaining knowledge. Interest has renewed in the classic pragmatists - Pierce, James, and Dewey - have an alternative to Rortys interpretation of the tradition.

The Philosophy of Mind, is the branch of philosophy that considers mental phenomena such as sensation, perception, thought, belief, desire, intention, memory, emotion, imagination, and purposeful action. These phenomena, which can be broadly grouped as thoughts and experiences, are features of human beings; many of them are also found in other animals. Philosophers are interested in the nature of each of these phenomena as well as their relationships to one another and to physical phenomena, such as motion.

The most famous exponent of dualism was the French philosopher René Descartes, who maintained that body and mind are radically different entities and that they are the only fundamental substances in the universe. Dualism, however, does not show how these basic entities are connected.

In the work of the German philosopher Gottfried Wilhelm Leibniz, the universe is held to consist of an infinite number of distinct substances, or monads. This view is pluralistic in the sense that it proposes the existence of many separate entities, and it is monistic in its assertion that each monad reflects within itself the entire universe.

Other philosophers have held that knowledge of reality is not derived from a priori principles, but is obtained only from experience. This type of metaphysics is called empiricism. Still another school of philosophy has maintained that, although an ultimate reality does exist, it is altogether inaccessible to human knowledge, which is necessarily subjective because it is confined to states of mind. Knowledge is therefore not a representation of external reality, but merely a reflection of human perceptions. This view is known as skepticism or agnosticism in respect to the soul and the reality of God.

The 18th-century German philosopher Immanuel Kant published his influential work The Critique of Pure Reason in 1781. Three years later, he expanded on his study of the modes of thinking with an essay entitled What is Enlightenment? In this 1784 essay, Kant challenged readers to dare to know, arguing that it was not only a civic but also a moral duty to exercise the fundamental freedoms of thought and expression.

Several major viewpoints were combined in the work of Kant, who developed a distinctive critical philosophy called transcendentalism. His philosophy is agnostic in that it denies the possibility of a strict knowledge of ultimate reality; it is empirical in that it affirms that all knowledge arises from experience and is true of objects of actual and possible experience; and it is rationalistic in that it maintains the a priori character of the structural principles of this empirical knowledge.

These principles are held to be necessary and universal in their application to experience, for in Kants view the mind furnishes the archetypal forms and categories (space, time, causality, substance, and relation) to its sensations, and these categories are logically anterior to experience, although manifested only in experience. Their logical anteriority to experience makes these categories or structural principles transcendental; they transcend all experience, both actual and possible. Although these principles determine all experience, they do not in any way affect the nature of things in themselves. The knowledge of which these principles are the necessary conditions must not be considered, therefore, as constituting a revelation of things as they are in themselves. This knowledge concerns things only insofar as they appear to human perception or as they can be apprehended by the senses. The argument by which Kant sought to fix the limits of human knowledge within the framework of experience and to demonstrate the inability of the human mind to penetrate beyond experience strictly by knowledge to the realm of ultimate reality constitutes the critical feature of his philosophy, giving the key word to the titles of his three leading treatises, Critique of Pure Reason, Critique of Practical Reason, and Critique of Judgment. In the system propounded in these works, Kant sought also to reconcile science and religion in a world of two levels, comprising noumena, objects conceived by reason although not perceived by the senses, and phenomena, things as they appear to the senses and are accessible to material study. He maintained that, because God, freedom, and human immortality are noumenal realities, these concepts are understood through moral faith rather than through scientific knowledge. With the continuous development of science, the expansion of metaphysics to include scientific knowledge and methods became one of the major objectives of metaphysicians.

Some of Kants most distinguished followers, notably Johann Gottlieb Fichte, Friedrich Schelling, Georg Wilhelm Friedrich Hegel, and Friedrich Schleiermacher, negated Kants criticism in their elaborations of his transcendental metaphysics by denying the Kantian conception of the thing-in-itself. They thus developed an absolute idealism in opposition to Kants critical transcendentalism.

Since the formation of the hypothesis of absolute idealism, the development of metaphysics has resulted in as many types of metaphysical theory as existed in pre-Kantian philosophy, despite Kants contention that he had fixed definitely the limits of philosophical speculation. Notable among these later metaphysical theories are radical empiricism, or pragmatism, a native American form of metaphysics expounded by Charles Sanders Peirce, developed by William James, and adapted as instrumentalism by John Dewey; voluntarism, the foremost exponents of which are the German philosopher Arthur Schopenhauer and the American philosopher Josiah Royce; phenomenalism, as it is exemplified in the writings of the French philosopher Auguste Comte and the British philosopher Herbert Spencer; emergent evolution, or creative evolution, originated by the French philosopher Henri Bergson; and the philosophy of the organism, elaborated by the British mathematician and philosopher Alfred North Whitehead. The salient doctrines of pragmatism are that the chief function of thought is to guide action, that the meaning of concepts is to be sought in their practical applications, and that truth should be tested by the practical effects of belief; according to instrumentalism, ideas are instruments of action, and their truth is determined by their role in human experience. In the theory of voluntarism the will are postulated as the supreme manifestation of reality. The exponents of phenomenalism, who are sometimes called positivists, contend that everything can be analyzed in terms of actual or possible occurrences, or phenomena, and that anything that cannot be analyzed in this manner cannot be understood. In emergent or creative evolution, the evolutionary process is characterized as spontaneous and unpredictable rather than mechanistically determined. The philosophy of the organism combines an evolutionary stress on constant process with a metaphysical theory of God, the external objects, and creativity.

In the 20th century the validity of metaphysical thinking has been disputed by the logical positivists and by the so-called dialectical materialism of the Marxists. The basic principle maintained by the logical positivists is the verifiability theory of meaning. According to this theory a sentence has factual meaning only if it meets the test of observation. Logical positivists argue that metaphysical expressions such as Nothing exists except material particles and Everything is part of one all-encompassing spirit cannot be tested empirically. Therefore, according to the verifiability theory of meaning, these expressions have no factual cognitive meaning, although they can have an emotive meaning relevant to human hopes and feelings.

The dialectical materialists assert that the mind is conditioned by and reflects material reality. Therefore, speculations that conceive of constructs of the mind as having any other than material reality are themselves unreal and can result only in delusion. To these assertions metaphysicians reply by denying the adequacy of the verifiability theory of meaning and of material perception as the standard of reality. Both logical positivism and dialectical materialism, they argue, conceal metaphysical assumptions, for example, that everything is observable or at least connected with something observable and that the mind has no distinctive life of its own. In the philosophical movement known as existentialism, thinkers have contended that the questions of the nature of being and of the individuals relationship to it are extremely important and meaningful in terms of human life. The investigation of these questions is therefore considered valid whether its results can be verified objectively.

Since the 1950s the problems of systematic analytical metaphysics have been studied in Britain by Stuart Newton Hampshire and Peter Frederick Strawson, the former concerned, in the manner of Spinoza, with the relationship between thought and action, and the latter, in the manner of Kant, with describing the major categories of experience as they are embedded in language. Metaphysics have been pursued much in the spirit of positivism by Wilfred Stalker Sellars and Willard Van Orman Quine. Sellars has sought to express metaphysical questions in linguistic terms, and Quine has attempted to determine whether the structure of language commits the philosopher to asserting the existence of any entities whatever and, if so, what kind. In these new formulations the issues of metaphysics and ontology remain vital.

n the 17th century, French philosopher René Descartes proposed that only two substances ultimately exist; mind and body. Yet, if the two are entirely distinct, as Descartes believed, how can one substance interact with the other? How, for example, is the intention of a human mind able to cause movement in the persons limbs? The issue of the interaction between mind and body is known in philosophy as the mind-body problem.

Many fields other than philosophy share an interest in the nature of mind. In religion, the nature of mind is connected with various conceptions of the soul and the possibility of life after death. In many abstract theories of mind there is considerable overlap between philosophy and the science of psychology. Once part of philosophy, psychology split off and formed a separate branch of knowledge in the 19th century. While psychology used scientific experiments to study mental states and events, philosophy uses reasoned arguments and thought experiments in seeking to understand the concepts that underlie mental phenomena. Also influenced by philosophy of mind is the field of artificial intelligence, which endeavours to develop computers that can mimic what the human mind can do. Cognitive science attempts to integrate the understanding of mind provided by philosophy, psychology, AI, and other disciplines. Finally, all of these fields benefit from the detailed understanding of the brain that has emerged through neuroscience in the late 20th century.

Philosophers use the characteristics of inward accessibility, subjectivity, intentionality, goal-directedness, creativity and freedom, and consciousness to distinguish mental phenomena from physical phenomena.

Perhaps the most important characteristic of mental phenomena is that they are inwardly accessible, or available to us through introspection. We each know our own minds - our sensations, thoughts, memories, desires, and fantasies - in a direct sense, by internal reflection. We also know our mental states and mental events in a way that no one else can. In other words, we have privileged access to our own mental states.

Certain mental phenomena, those we generally call experiences, have a subjective nature - that is, they have certain characteristics we become aware of when we reflect, for instance, there is something as definitely to feel pain, or have an itch, or see something red. These characteristics are subjective in that they are accessible to the subject of the experience, the person who has the experience, but not to others.

Other mental phenomena, which we broadly refer to as thoughts, have a characteristic philosophers call intentionality. Intentional thoughts are about other thoughts or objects, which are represented as having certain properties or for being related to one another in a certain way. The belief that London is west of Toronto, for example, is about London and Toronto and represents the former as west of the latter. Although we have privileged access to our intentional states, many of them do not seem to have a subjective nature, at least not in the way that experiences do.

The contrast between the subjective and the objective is made in both the epistemic and the ontological divisions of knowledge. In the objective field of study, it is oftentimes identified with the distension between the intrapersonal and the interpersonal, or with that between matters whose resolving power depends on the psychology of the person in question, and who in this way is dependent, or, sometimes, with the distinction between the biased and the impartial. Therefore, an objective question might be one answerable by a method usable by any competent investigator, while a subjective question would be answerable only from the questioners point of view. In the ontological domain, the subjective-objective contrast is often between what is what is not mind-dependent: Secondary qualities, e.g., colours, have been variability with observation conditions. The truth of a proposition, for instance: Apart from certain propositions about oneself, would be objective if it is interdependent of the perspective, especially for beliefs of those judging it. Truth would be subjective if it lacks such independence, because it is a construct from justified beliefs, e.g., those well-confirmed by observation.

One notion of objectivity can be basic and the other as an end point of reasoning and observation, if only to infer of it as a conclusion. If the epistemic notion is essentially an underlying of something as related to or dealing with such that are to fundamental primitives, then the criteria for objectivity in the ontological sense derive from considerations of justification: An objective question is one answerable by a procedure that yields (adequate) justification is a matter of amenability to such a means or procedures used to attaining an end. , its method, if, on the other hand, the ontological notion is basic, the criteria for an interpersonal method and its objective use are a matter of its mind-independence and tendency to lead to objective truth, perhaps, its applying to external objects and yielding predictive success. Since, the use of these criteria requires employing the methods which, on the epistemic conception, define objectivists most notably scientific methods - but no similar dependence obtains in the other direction, the epistemic notion os often taken as basic.

A different theory of truth, or the epistemic theory, is motivated by the desire to avoid negative features of the correspondence theory, which celebrates the existence of God, whereby, its premises are that all natural things are dependent for their existence on something else, whereas the totality of dependent beings must then itself depend upon a non-dependent, or necessarily existent, being, which is God. So, the God that ends the question must exist necessarily, it must not be an entity of which the same kinds of questions can be raised. The problem with such is the argument that it unfortunately affords no reason for attributing concern and care to the deity, nor for connecting the necessarily existent being it derives with human values and aspirations.

This presents in truth as that which is licenced by our best theory of reality, but truth is distributively contributed as a function of our thinking about the world and all surrounding surfaces. An obvious problem with this is the fact of revision; theories are constantly refined and corrected. To deal with this objection it is at the end of enquiry. We never in fact reach it, but it serves as a direct motivational disguised enticement, as an asymptotic end of enquiry. Nonetheless, the epistemic theory of truth is not antipathetic to ontological relativity, since it has no commitment to the ultimate furniture of the world and it also is open to the possibilities of some kinds of epistemological relativism.

Lest bet be said, however, that of epistemology, the subjective-objective contrast arises above all for the concept of justification and its relatives. Externalism, particularly reliabilism, and since, for reliabilism, truth-conduciveness (non-subjectivity conceived) is central for justified belief. Internalism may or may not construe justification subjectivistically, depending on whether the proposed epistemic standards are interpersonally grounded. There are also various kinds of subjectivity: Justification may, e.g., be grounded in ones considered standards of simply in what one believes to be sound. Yet, justified beliefs accorded with precise or explicitly considered standards whether or not deem it a purposive necessity to think them justifiably made so.

Any conception of objectivity may treat one domain as fundamental and the others derivatively. Thus, objectivity for methods (including sensory observation) might be thought basic. Let us look upon an objective method be that one is (1) interpersonally usable and tends to yield justification regarding the questions to which it applies (an epistemic conception), or (2) trends to yield truth when properly applied (an ontological conception) or (3) both. Then an objective person is one who appropriately uses objective methods by an objective method, as one appraisable by an objective method, an objective discipline is whose methods are objective, and so on. Typically, those who conceive objectivity epistemically tend to take methods as fundamental, and those who conceive it ontologically tend to take statements as basic.

A number of mental phenomena appear to be connected to one another as elements in an intelligent, goal-directed system. The system works as follows: First, our sense organs are stimulated by events in our environment; next, by virtue of these stimulations, we perceive things about the external world; finally, we use this information, as well as information we have remembered or inferred, to guide our actions in ways that further our goals. Goal-directedness seems to accompany only mental phenomena.

Another important characteristic of mind, especially of human minds, is the capacity for choice and imagination. Rather than automatically converting past influences into future actions, individual minds are capable of exhibiting creativity and freedom. For instance, we can imagine things we have not experienced and can act in ways that no one expects or could predict.

Mental phenomena are conscious, and consciousness may be the closest term we have for describing what is special about mental phenomena. Minds are sometimes referred to as consciousness, yet it is difficult to describe exactly what consciousness is. Although consciousness is closely related to inward accessibility and subjectivity, these very characteristics seem to hinder us in reaching an objective scientific understanding of it.

Although philosophers have written about mental phenomena since ancient times, the philosophy of mind did not garner much attention until the work of French philosopher René Descartes in the 17th century. Descartes work represented a turning point in thinking about mind by making a strong distinction between bodies and minds, or the physical and the mental. This duality between mind and body, known as Cartesian dualism, has posed significant problems for philosophy ever since.

Descartes believed there are two basic kinds of things in the world, a belief known as substance dualism. For Descartes, the principles of existence for these two groups of things - bodies and minds - are completely different from one another: Bodies exist by being extended in space, while minds exist by being conscious. According to Descartes, nothing can be done to give a body thought and consciousness. No matter how we shape a body or combine it with other bodies, we cannot turn the body into a mind, a thing that is conscious, because being conscious is not a way of being extended.

For Descartes, a person consists of a human body and a human mind causally interacting with one another. For example, the intentions of a human being, that may have conceivably, caused that persons limbs to move. In this way, the mind can affect the body. In addition, the sense organs of a human being as forced, in effect of a refractive ray of light, pressure, or sound, external sources which in turn affect the brain, affecting mental states. Thus the body may affect the mind. Exactly how mind can affect body, and vice versa, is a central issue in the philosophy of mind, and is known as the mind-body problem. According to Descartes, this interaction of mind and body is peculiarly intimate. Unlike the interaction between a pilot and his ship, the connexion between mind and body more closely resembles two substances that have been thoroughly mixed together.

In response to the mind-body problem arising from Descartes theory of substance dualism, a number of philosophers have advocated various forms of substance monism, the doctrine that there is ultimately just one kind of thing in reality. In the 18th century, Irish philosopher George Berkeley claimed there were no material objects in the world, only minds and their ideas. Berkeley thought that talk about physical objects was simply a way of organizing the flow of experience. Near the turn of the 20th century, American psychologist and philosopher William James proposed another form of substance monism. James claimed that experience is the basic stuff from which both bodies and minds are constructed.

Most philosophers of mind today are substance monists of a third type: They are materialists who believe that everything in the world is basically material, or a physical object. Among materialists, there is still considerable disagreement about the status of mental properties, which are conceived as properties of bodies or brains. Materialists who those properties undersized by duality, yet believe that mental properties are an additional kind of property or attribute, not reducible to physical properties. Property diarists have the problem of explaining how such properties can fit into the world envisaged by modern physical science, according to which there are physical explanations for all things.

Materialists who are property monists believe that there is ultimately only one type of property, although they disagree on whether or not mental properties exist in material form. Some property monists, known as reductive materialists, hold that mental properties exist simply as a subset of relatively complex and non-basic physical properties of the brain. Reductive materialists have the problem of explaining how the physical states of the brain can be inwardly accessible and have a subjective character, as mental states do. Other property monists, known as eliminative materialists, consider the whole category of mental properties to be a mistake. According to them, mental properties should be treated as discredited postulates of an outmoded theory. Eliminative materialism is difficult for most people to accept, since we seem to have direct knowledge of our own mental phenomena by introspection and because we use the general principles we understand about mental phenomena to predict and explain the behavior of others.

Philosophy of mind concerns itself with a number of specialized problems. In addition to the mind-body problem, important issues include those of personal identity, immortality, and artificial intelligence.

During much of Western history, the mind has been identified with the soul as presented in Christian theology. According to Christianity, the soul is the source of a persons identity and is usually regarded as immaterial; thus it is capable of enduring after the death of the body. Descartes conception of the mind as a separate, nonmaterial substance fits well with this understanding of the soul. In Descartes view, we are aware of our bodies only as the cause of sensations and other mental phenomena. Consequently our personal essence is composed more fundamentally of mind and the preservation of the mind after death would constitute our continued existence.

The mind conceived by materialist forms of substance monism does not fit as neatly with this traditional concept of the soul. With materialism, once a physical body is destroyed, nothing enduring remains. Some philosophers think that a concept of personal identity can be constructed that permits the possibility of life after death without appealing to separate immaterial substances. Following in the tradition of 17th-century British philosopher John Locke, these philosophers propose that a person consists of a stream of mental events linked by memory. It is these links of memory, rather than a single underlying substance, that provides the unity of a single consciousness through time. Immortality is conceivable if we think of these memory links as connecting a later consciousness in heaven with an earlier one on Earth.

The field of artificial intelligence also raises interesting questions for the philosophy of mind. People have designed machines that mimic or model many aspects of human intelligence, and there are robots currently in use whose behavior is described in terms of goals, beliefs, and perceptions. Such machines are capable of behavior that, were it exhibited by a human being, would surely be taken to be free and creative. As an example, in 1996 an IBM computer named Deep Blue won a chess game against Russian world champion Garry Kasparov under international match regulations. Moreover, it is possible to design robots that have some sort of privileged access to their internal states. Philosophers disagree over whether such robots truly think or simply appear to think and whether such robots should be considered to be conscious

Dualism, in philosophy, the theory that the universe is explicable only as a whole composed of two distinct and mutually irreducible elements. In Platonic philosophy the ultimate dualism is between being and nonbeing - that is, between ideas and matter. In the 17th century, dualism took the form of belief in two fundamental substances: mind and matter. French philosopher René Descartes, whose interpretation of the universe exemplifies this belief, was the first to emphasize the irreconcilable difference between thinking substance (mind) and extended substance (matter). The difficulty created by this view was to explain how mind and matter interact, as they apparently do in human experience. This perplexity caused some Cartesians to deny entirely any interaction between the two. They asserted that mind and matter are inherently incapable of affecting each other, and that any reciprocal action between the two is caused by God, who, on the occasion of a change in one, produces a corresponding change in the other. Other followers of Descartes abandoned dualism in favor of monism.

In the 20th century, reaction against the monistic aspects of the philosophy of idealism has to some degree revived dualism. One of the most interesting defences of dualism is that of Anglo-American psychologist William McDougall, who divided the universe into spirit and matter and maintained that good evidence, both psychological and biological, indicates the spiritual basis of physiological processes. French philosopher Henri Bergson in his great philosophic work Matter and Memory likewise took a dualistic position, defining matter as what we perceive with our senses and possessing in itself the qualities that we perceive in it, such as colour and resistance. Mind, on the other hand, reveals itself as memory, the faculty of storing up the past and utilizing it for modifying our present actions, which otherwise would be merely mechanical. In his later writings, however, Bergson abandoned dualism and came to regard matter as an arrested manifestation of the same vital impulse that composes life and mind.

Dualism, in philosophy, the theory that the universe is explicable only as a whole composed of two distinct and mutually irreducible elements. In Platonic philosophy the ultimate dualism is between being and nonbeing - that is, between ideas and matter. In the 17th century, dualism took the form of belief in two fundamental substances: mind and matter. French philosopher René Descartes, whose interpretation of the universe exemplifies this belief, was the first to emphasize the irreconcilable difference between thinking substance (mind) and extended substance (matter). The difficulty created by this view was to explain how mind and matter interact, as they apparently do in human experience. This perplexity caused some Cartesians to deny entirely any interaction between the two. They asserted that mind and matter are inherently incapable of affecting each other, and that any reciprocal action between the two is caused by God, who, on the occasion of a change in one, produces a corresponding change in the other. Other followers of Descartes abandoned dualism in favor of monism.

In the 20th century, reaction against the monistic aspects of the philosophy of idealism has to some degree revived dualism. One of the most interesting defences of dualism is that of Anglo-American psychologist William McDougall, who divided the universe into spirit and matter and maintained that good evidence, both psychological and biological, indicates the spiritual basis of physiological processes. French philosopher Henri Bergson in his great philosophic work Matter and Memory likewise took a dualistic position, defining matter as what we perceive with our senses and possessing in itself the qualities that we perceive in it, such as colour and resistance. Mind, on the other hand, reveals itself as memory, the faculty of storing up the past and utilizing it for modifying our present actions, which otherwise would be merely mechanical. In his later writings, however, Bergson abandoned dualism and came to regard matter as an arrested manifestation of the same vital impulse that composes life and mind.

For many people understanding the place of mind in nature is the greatest philosophical problem. Mind is often though to be the last domain that stubbornly resists scientific understanding and philosophers defer over whether they find that cause for celebration or scandal. The mind-body problem in the modern era was given its definitive shape by Descartes, although the dualism that he espoused is in some form whatever there is a religious or philosophical tradition there is a religious or philosophical tradition whereby the soul may have an existence apart from the body. While most modern philosophers of mind would reject the imaginings that lead us to think that this makes sense, there is no consensus over the best way to integrate our understanding of people as bearers of physical properties lives on the other.

Occasionalist find from it term as employed to designate the philosophical system devised by the followers of the 17th-century French philosopher René Descartes, who, in attempting to explain the interrelationship between mind and body, concluded that God is the only cause. The occasionalists began with the assumption that certain actions or modifications of the body are preceded, accompanied, or followed by changes in the mind. This assumed relationship presents no difficulty to the popular conception of mind and body, according to which each entity is supposed to act directly on the other; these philosophers, however, asserting that cause and effect must be similar, could not conceive the possibility of any direct mutual interaction between substances as dissimilar as mind and body.

According to the occasionalists, the action of the mind is not, and cannot be, the cause of the corresponding action of the body. Whenever any action of the mind takes place, God directly produces in connexion with that action, and by reason of it, a corresponding action of the body; the converse process is likewise true. This theory did not solve the problem, for if the mind cannot act on the body (matter), then God, conceived as mind, cannot act on matter. Conversely, if God is conceived as other than mind, then he cannot act on mind. A proposed solution to this problem was furnished by exponents of radical empiricism such as the American philosopher and psychologist William James. This theory disposed of the dualism of the occasionalists by denying the fundamental difference between mind and matter.

Generally, along with consciousness, that experience of an external world or similar scream or other possessions, takes upon itself the visual experience or deprive of some normal visual experience, that this, however, does not perceive the world accurately. In its frontal experiment. As researchers reared kittens in total darkness, except that for five hours a day the kittens were placed in an environment with only vertical lines. When the animals were later exposed to horizontal lines and forms, they had trouble perceiving these forms.

While, in the theory of probability the Cambridge mathematician and philosopher Frank Ramsey (1903-30), was the first to show how a personalized theory could be developed, based on precise behavioural notions of preference and expectation. In the philosophy of language, Ramsey was one of the first thinkers to accept a redundancy theory of truth, which he combined with radical views of the function of many kinds of propositions. Neither generalizations nor causal propositions, nor those treating probability or ethics, described facts, but each has a different specific function in our intellectual economy.

Ramsey advocates that of a sentence generated by taking all the sentence affirmed in a scientific theory that use some term, e.g., quark. Replacing the term by a variable, and existentially quantifying into the result. Instead of saying quarks have such-and-such properties, Ramsey postdated that the sentence as saying that there is something that has those properties. If the process is repeated, the sentence gives the topic-neutral structure of the theory, but removes any implications that we know what the term so treated denote. It leaves open the possibility of identifying the theoretical item with whatever, and it is that best fits the description provided. Nonetheless, it was pointed out by the Cambridge mathematician Newman that if the process is carried out for all except the logical bones of the theory, then by the Löwenheim-Skolem theorem, the result will be interpretable in any domain of sufficient cardinality, and the content of the theory may reasonably be felt to have been lost.

Nevertheless, probability is a non-negative, additive set function whose maximum value is unity. What is harder to understand is the application of the formal notion to the actual world. One point of application is statistical, when kinds of event or trials (such as the tossing of a coin) can be described, and the frequency of occurrence of particular outcomes (such as the coin falling heads) is measurable, then we can begin to think of the probability of that kind of outcome in that kind of trial. One account of probability is therefore the frequency theory, associated with Venn and Richard von Mises (1883-1953), that identifies the probability of an event with such a frequency of occurrence. A second point of application is the description of an hypothesis as probable when the evidence bears a favoured relation is conceived of as purely logical in nature, as in the works of Keynes and Carnap, probability statement are not empirical measures of frequency, but represent something like partial entailments or measures of possibilities left open by the evidence and by the hypothesis.

Formal confirmation theories and range theories of probability are developments of this idea. The third point of application is in the use probability judgements have in regulating the confidence with which we hold various expectations. The approach sometimes called subjectivism or personalism, but more commonly known as Bayesianism, associated with de Finetti and Ramsey, whom of both, see probability judgements as expressions of a subjects degree of confidence in an event or kind of event, and attempts to describe constraints on the way we should have degrees of confidence in different judgements that explain those judgements having the mathematical form of judgements of probability. For Bayesianism, probability or chance is probability or chance is not an objective or real factor in the world, but rather a reflection of our own states of mind. However, these states of mind need to be governed by empirical frequencies, so this is not an invitation to licentious thinking.

This concept of sampling and accompanying application of the laws of probability find extensive use in polls, public opinion polls. Polls to determine what radio or television program is being watched and listened to, polls to determine house-wives reaction to a new product, political polls, and the like. In most cases the sampling is carefully planned and often a margin of error is stated. Polls cannot, however, altogether eliminate the fact that certain people dislike being questioned and may deliberately conceal or give false information. In spite of this and other objections, the method of sampling often makes results available in situations where the cost of complete enumeration would be prohibitive both from the standpoint of time and of money.

Thus we can see that probability and statistics are used in insurance, physics, genetics, biology, business, as well as in games of chance, and we are inclined to agree with P.S. LaPlace who said: We see . . . that the theory of probabilities is at bottom only common sense reduced to calculation, it makes us appreciate with exactitude what reasonable minds feel by a sort of instinct, often being able to account for it . . . it is remarkable that [this] science, which originated in the consideration of games of chance, should have become the most important object of human knowledge.

It seems, that the most taken of are the paradoxes in the foundations of set theory as discovered by Russell in 1901. Some classes have themselves as members: The class of all abstract objects, for example, is an abstract object, whereby, others do not: The class of donkeys is not itself a donkey. Now consider the class of all classes that are not members of themselves, is this class a member of itself, that, if it is, then it is not, and if it is not, then it is.

The paradox is structurally similar to easier examples, such as the paradox of the barber. Such one like a village having a barber in it, who shaves all and only the people who do not have in themselves. Who shaves the barber? If he shaves himself, then he does not, but if he does not shave himself, then he does not. The paradox is actually just a proof that there is no such barber or in other words, that the condition is inconsistent. All the same, it is no too easy to say why there is no such class as the one Russell defines. It seems that there must be some restriction on the kind of definition that are allowed to define classes and the difficulty that of finding a well-motivated principle behind any such restriction.

The French mathematician and philosopher Henri Jules Poincaré (1854-1912) believed that paradoxes like those of Russell and the barber were due to such as the impredicative definitions, and therefore proposed banning them. But, it turns out that classical mathematics required such definitions at too many points for the ban to be easily absolved. Having, in turn, as forwarded by Poincaré and Russell, was that in order to solve the logical and semantic paradoxes it would have to ban any collection (set) containing members that can only be defined by means of the collection taken as a whole. It is, effectively by all occurring principles into which have an adopting vicious regress, as to mark the definition for which involves no such failure. There is frequently room for dispute about whether regresses are benign or vicious, since the issue will hinge on whether it is necessary to reapply the procedure. The cosmological argument is an attempt to find a stopping point for what is otherwise seen for being an infinite regress, and, to ban of the predicative definitions.

The investigation of questions that arise from reflection upon sciences and scientific inquiry, are such as called of a philosophy of science. Such questions include, what distinctions in the methods of science? s there a clear demarcation between scenes and other disciplines, and how do we place such enquires as history, economics or sociology? And scientific theories probable or more in the nature of provisional conjecture? Can the be verified or falsified? What distinguished good from bad explanations? Might there be one unified since, embracing all special sciences? For much of the 20th century their questions were pursued in a highly abstract and logical framework it being supposed that as general logic of scientific discovery that a general logic of scientific discovery a justification might be found. However, many now take interests in a more historical, contextual and sometimes sociological approach, in which the methods and successes of a science at a particular time are regarded less in terms of universal logical principles and procedure, and more in terms of their availability to methods and paradigms as well as the social context.

In addition, to general questions of methodology, there are specific problems within particular sciences, giving subjects as biology, mathematics and physics.

The intuitive certainty that sparks aflame the dialectic awarenesses for its immediate concerns are either of the truth or by some other in an object of apprehensions, such as a concept. Awareness as such, has to its amounting quality value the place where philosophical understanding of the source of our knowledge are, however, in covering the sensible apprehension of things and pure intuition it is that which structural sensation into the experience of things accent of its direction that orchestrates the celestial overture into measures in space and time.

The notion that determines how something is seen or evaluated of the status of law and morality especially associated with St. Thomas Aquinas and the subsequent scholastic tradition. More widely, any attempt to cement the moral and legal order together with the nature of the cosmos or how the nature of human beings, for which sense it is also found in some Protestant writers, and arguably derivative from a Platonic view of ethics, and is implicit in ancient Stoicism. Law stands above and apart from the activities of human lawmaker, it constitutes an objective set of principles that can be seen true by natural light or reason, and (in religion versions of the theory) that express Gods’ will for creation. Non-religious versions of the theory substitute objective conditions for human flourishing as the source of constraints upon permissible actions and social arrangements. Within the natural law tradition, different views have been held about the relationship between the rule of law about God s will, for instance the Dutch philosopher Hugo Grothius (1583-1645), similarly takes upon the view that the content of natural law is independent of any will, including that of God, while the German theorist and historian Samuel von Pufendorf (1632-94) takes the opposite view, thereby facing the problem of one horn of the Euthyphro dilemma, that simply states, that its dilemma arises from whatever the source of authority is supposed to be, for in which do we care about the general good because it is good, or do we just call good things that we care about. Wherefore, by facing the problem that may be to assume of a strong form, in which it is claimed that various facts entail values, or a weaker form, from which it confines itself to holding that reason by itself is capable of discerning moral requirements that are supposedly of binding to all human bings regardless of their desires

Although the morality of people send the ethical amount from which the same thing, is that there is a usage that restricts morality to systems such as that of the German philosopher and founder of ethical philosophy Immanuel Kant (1724-1804), based on notions such as duty, obligation, and principles of conduct, reserving ethics for more than the Aristotelian approach to practical reasoning based on the notion of a virtue, and generally avoiding the separation of moral considerations from other practical considerations. The scholarly issues are complex, with some writers seeing Kant as more Aristotelian and Aristotle as, ore involved in a separate sphere of responsibility and duty, than the simple contrast suggests. Some theorists see the subject in terms of a number of laws (as in the Ten Commandments). The status of these laws may be test, and they are the edicts of a divine lawmaker, or that they are truth of reason, knowable deductively. Other approaches to ethics (e.g., eudaimonism, situational ethics, virtue ethics) eschew general principles as much as possible, frequently disguising the great complexity of practical reasoning. For Kantian notion of the moral law is a binding requirement of the categorical imperative, and to understand whether they are equivalent at some deep level. Kants own applications of the notion are not always convincing, as for one cause of confusion in relating Kants ethics to theories such additional expressivism, is that it is easy, but mistaken, to suppose that the categorical nature of the imperative means that it cannot be the expression of sentiment, but must derive from something unconditional or necessary such as the voice of reason.

For which ever reason, the mortal being makes of its presence to the future of weighing of that which one must do, or that which can be required of one. The term carries implications of that which is owed (due) to other people, or perhaps in oneself. Universal duties would be owed to persons (or sentient beings) as such, whereas special duty in virtue of specific relations, such for being the child of someone, or having made someone a promise. Duty or obligation is the primary concept of deontological approaches to ethics, but is constructed in other systems out of other notions. In the system of Kant, a perfect duty is one that must be performed whatever the circumstances: Imperfect duties may have to give way to the more stringent ones. In another way, perfect duties are those that are correlative with the right to others, imperfect duties are not. Problems with the concept include the ways in which due needs to be specified (a frequent criticism of Kant is that his notion of duty is too abstract). The concept may also suggest of a regimented view of ethical life in which we are all forced conscripts in a kind of moral army, and may encourage an individualistic and antagonistic view of social relations.

The most generally accepted account of externalism and/or internalism, that this distinction is that a theory of justification is internalist if only if it requiem that all of the factors needed for a belief to be epistemologically justified for a given person be cognitively accessible to that person, internal to his cognitive perception, and externalist, if it allows that at least some of the justifying factors need not be thus accessible, so that they can be external to the believers cognitive perceptive, beyond any such given relations. However, epistemologists often use the distinction between internalist and externalist theories of epistemic justification without offering any very explicit explication.

The externalist/internalist distinction has been mainly applied to theories of epistemic justification: It has also been applied in a closely related way to accounts of knowledge and in a rather different way to accounts of belief and thought contents.

The internalist requirement of cognitive accessibility can be interpreted in at least two ways: A strong version of internalism would require that the believer actually be aware of the justifying factor in order to be justified: While a weaker version would require only that he be capable of becoming aware of them by focussing his attentions appropriately, but without the need for any change of position, new information, etc. Though the phrase cognitively accessible suggests the weak interpretation, the main intuitive motivation for internalism, viz. the idea that epistemic justification requires that the believer actually have in his cognitive possession a reason for thinking that the belief is true, and would require the strong interpretation.

Perhaps, the clearest example of an internalist position would be a Foundationalist view according to which foundational beliefs pertain to immediately experienced states of mind and other beliefs are justified by standing in cognitively accessible logical or inferential relations to such foundational beliefs. Such a view could count as either a strong or a weak version of internalism, depending on whether actual awareness of the justifying elements or only the capacity to become aware of them is required. Similarly, a current view could also be internalist, if both the beliefs or other states with which a justification belief is required to cohere and the coherence relations themselves are reflectively accessible.

It should be carefully noticed that when internalism is construed in this way, it is neither necessary nor sufficient by itself for internalism that the justifying factors literally be internal mental states of the person in question. Not necessary, necessary, because on at least some views, e.g., a direct realist view of perception, something other than a mental state of the believer can be cognitively accessible: Not sufficient, because there are views according to which at least some mental states need not be actual (strong version) or even possible (weak version) objects of cognitive awareness. Also, on this way of drawing the distinction, a hybrid view, according to which some of the factors required for justification must be cognitively accessible while others need not and in general will not be, would count as an externalist view. Obviously too, a view that was externalist in relation to a strong version of internalism (by not requiring that the believer actually be aware of all justifying factors) could still be internalist in relation to a weak version (by requiring that he at least be capable of becoming aware of them).

The most prominent recent externalist views have been versions of Reliabilism, whose requirements for justification is roughly that the belief be produced in a way or via a process that makes of objectively likely that the belief is true. What makes such a view externalist is the absence of any requirement that the person for whom the belief is justified have any sort of cognitive access to the relations of reliability in question. Lacking such access, such a person will in general have no reason for thinking that the belief is true or likely to be true , but will, on such an account, nonetheless be epistemically justified in according it. Thus such a view arguably marks a major break from the modern epistemological tradition, stemming from Descartes, which identifies epistemic justification with having a reason, perhaps even a conclusive reason for thinking that the belief is true. An epistemologist working within this tradition is likely to feel that the externalist, than offering a competing account of the same concept of epistemic justification with which the traditional epistemologist is concerned, has simply changed the subject.

The main objection to externalism rests on the intuitive certainty that the basic requirement for epistemic justification is that the acceptance of the belief in question be rational or responsible in relation to the cognitive goal of truth, which seems to require in turn that the believer actually be dialectally aware of a reason for thinking that the belief is true (or, at the very least, that such a reason be available to him). Since the satisfaction of an externalist condition is neither necessary nor sufficient for the existence of such a cognitively accessible reason, it is argued, externalism is mistaken as an account of epistemic justification. This general point has been elaborated by appeal to two sorts of putative intuitive counter-examples to externalism. The first of these challenges the necessity of belief which seem intuitively to be justified, but for which the externalist conditions are not satisfied. The standard examples in this sort are cases where beliefs are produced in some very nonstandard way, e.g., by a Cartesian demon, but nonetheless, in such a way that the subjective experience of the believer is indistinguishable from that of someone whose beliefs are produced more normally. The intuitive claim is that the believer in such a case is nonetheless epistemically justified, as much so as one whose belief is produced in a more normal way, and hence that externalist account of justification must be mistaken.

Perhaps the most striking reply to this sort of counter-example, on behalf of a cognitive process is to be assessed in normal possible worlds, i.e., in possible worlds that are actually the way our world is common-seismically believed to be, than in the world which contains the belief being judged. Since the cognitive processes employed in the Cartesian demon cases are, for which we may assume, reliable when assessed in this way, the reliabilist can agree that such beliefs are justified. The obvious, to a considerable degree of bringing out the issue of whether it is or not an adequate rationale for this construal of Reliabilism, so that the reply is not merely a notional presupposition guised as having representation.

The correlative way of elaborating on the general objection to justificatory externalism challenges the sufficiency of the various externalist conditions by citing cases where those conditions are satisfied, but where the believers in question seem intuitively not to be justified. In this context, the most widely discussed examples have to do with possible occult cognitive capacities, like clairvoyance. Considering the point in application once, again, to Reliabilism, the claim is that to think that he has such a cognitive power, and, perhaps, even good reasons to the contrary, is not rational or responsible and therefore not epistemically justified in accepting the belief that result from his clairvoyance, despite the fact that the reliabilist condition is satisfied.

One sort of response to this latter sorts of objection is to bite the bullet and insist that such believers are in fact justified, dismissing the seeming intuitions to the contrary as latent internalist prejudice. A more widely adopted response attempts to impose additional conditions, usually of a roughly internalist sort, which will rule out the offending example, while stopping far of a full internalism. But, while there is little doubt that such modified versions of externalism can handle particular cases, as well enough to avoid clear intuitive implausibility, the usually problematic cases that they cannot handle, and also whether there is and clear motivation for the additional requirements other than the general internalist view of justification that externalist are committed to reject.

A view in this same general vein, one that might be described as a hybrid of internalism and externalism holds that epistemic justification requires that there is a justificatory factor that is cognitively accessible to the believer in question (though it need not be actually grasped), thus ruling out, e.g., a pure Reliabilism. At the same time, however, though it must be objectively true that beliefs for which such a factor is available are likely to be true, in addition, the fact need not be in any way grasped or cognitively accessible to the believer. In effect, of the premises needed to argue that a particular belief is likely to be true, one must be accessible in a way that would satisfy at least weak internalism, the internalist will respond that this hybrid view is of no help at all in meeting the objection and has no belief nor is it held in the rational, responsible way that justification intuitively seems to require, for the believer in question, lacking one crucial premise, still has no reason at all for thinking that his belief is likely to be true.

An alternative to giving an externalist account of epistemic justification, one which may be more defensible while still accommodating many of the same motivating concerns, is to give an externalist account of knowledge directly, without relying on an intermediate account of justification. Such a view will obviously have to reject the justified true belief account of knowledge, holding instead that knowledge is true belief which satisfies the chosen externalist condition, e.g., a result of a reliable process (and perhaps, further conditions as well). This makes it possible for such a view to retain internalist account of epistemic justification, though the centrality of that concept to epistemology would obviously be seriously diminished.

Such an externalist account of knowledge can accommodate the commonsense conviction that animals, young children, and unsophisticated adults posses knowledge, though not the weaker conviction (if such a conviction does exist) that such individuals are epistemically justified in their beliefs. It is also at least less vulnerable to internalist counter-examples of the sort discussed, since the intuitions involved there pertain more clearly to justification than to knowledge. What is uncertain is what ultimate philosophical significance the resulting conception of knowledge is supposed to have. In particular, does it have any serious bearing on traditional epistemological problems and on the deepest and most troubling versions of scepticism, which seems in fact to be primarily concerned with justification, that of knowledge?`

A rather different use of the terms internalism and externalism has to do with the issue of how the content of beliefs and thoughts is determined: According to an internalist view of content, the content of such intention states depends only on the non-relational, internal properties of the individuals mind or grain, and not at all on his physical and social environment: While according to an externalist view, content is significantly affected by such external factors and suggests a view that appears of both internal and external elements is standardly classified as an external view.

As with justification and knowledge, the traditional view of content has been strongly internalist in character. The main argument for externalism derives from the philosophy y of language, more specifically from the various phenomena pertaining to natural kind terms, indexicals, etc. that motivate the views that have come to be known as direct reference theories. Such phenomena seem at least to show that the belief or thought content that can be properly attributed to a person is dependent on facts about his environment - e.g., whether he is on Earth or Twin Earth, what is fact pointing at, the classificatory criteria employed by expects in his social group, etc. - not just on what is going on internally in his mind or brain.

An objection to externalist account of content is that they seem unable to do justice to our ability to know the content of our beliefs or thought from the inside, simply by reflection. If content is depending on external factors pertaining to the environment, then knowledge of content should depend on knowledge of these factors - which will not in general be available to the person whose belief or thought is in question.

The adoption of an externalist account of mental content would seem to support an externalist account of justification, by way that if part or all of the content of a belief inaccessible to the believer, then both the justifying status of other beliefs in relation to that content and the status of that content as justifying further beliefs will be similarly inaccessible, thus contravening the internalist requirement for justification. An internalist must insist that there are no justification relations of these sorts, that our internally associable content can be either justified or justly for anything else: But such a response appears lame unless it is coupled with an attempt to show that the externalist account of content is mistaken.

In addition, to what to the Foundationalist, but the view in epistemology that knowledge must be regarded as a structure raised upon secure, certain foundations. These are found in some combination of experience and reason, with different schools (empirical, rationalism) emphasizing the role of one over that of the other. Foundationalism was associated with the ancient Stoics, and in the modern era with Descartes, who discovered his foundations in the clear and distinct ideas of reason. Its main opponent is Coherentism or the view that a body of propositions my be known without as foundation is certain, but by their interlocking strength. Rather as a crossword puzzle may be known to have been solved correctly even if each answer, taken individually, admits of uncertainty.

Truth, alone with coherence is the study of concept, in such a study in philosophy is that it treats both the meaning of the word true and the criteria by which we judge the truth or falsity in spoken and written statements. Philosophers have attempted to answer the question What is truth? for thousands of years. The four main theories they have proposed to answer this question are the correspondence, pragmatic, coherence, and deflationary theories of truth.

There are various ways of distinguishing types of Foundationalist epistemology by the use of the variations that have been enumerating. Planntinga has put forward an influence conception of classical Foundationalism, specified in terms of limitations on the foundations. He construes this as a disjunction of ancient and medieval Foundationalism;, which takes foundations to comprise that with self-evident and evident to the senses, and modern Foundationalism that replace evident Foundationalism that replaces evident to the senses with the replaces of evident to the senses with incorrigibly, which in practice was taken to apply only to beliefs bout ones present state of consciousness? Plantinga himself developed this notion in the context of arguing that items outside this territory, in particular certain beliefs about God, could also be immediately justified. A popular recent distinction is between what is variously strong or extremely Foundationalism and moderate, modest or minimal and moderately modest or minimal Foundationalism with the distinction depending on whether epistemic immunities are reassured of foundations. While depending on whether it require of a foundation only that it be required of as foundation, that only it be immediately justified, or whether it be immediately justified. In that it make just the comforted preferability, only to suggest that the plausibility of the string requiring stems from both a level confusion between beliefs on different levels.

Emerging sceptic tendencies come forth in the 14th-century writings of Nicholas of Autrecourt. His criticisms of any certainty beyond the immediate deliverance of the senses and basic logic, and in particular of any knowledge of either intellectual or material substances, anticipate the later scepticism of Balye and Hume. The; latter distinguishes between Pyrrhonistic and excessive scepticism, which he regarded as unlivable, and the more mitigated scepticism that accepts every day or commonsense beliefs (not as the delivery of reason, but as due more to custom and habit), but is duly wary of the power of reason to give us much more. Mitigated scepticism is thus closer to the attitude fostered by ancient scepticism from Pyrrho through to Sexus Empiricus. Although the phrase Cartesian scepticism is sometimes used, Descartes himself was not a sceptic, but in the method of doubt, uses a sceptical scenario in order to begin the process of finding a secure mark of knowledge. Descartes himself trusts a category of clear and distinct ideas, not far removed from the phantasia kataleptiké of the Stoics.

Scepticism should not be confused with relativism, which is a doctrine about the nature of truth, and may be motivated by trying to avoid scepticism. Nor is it identical with eliminativism, which counsels abandoning an area of thought together, not because we cannot know the truth, but because there are no truth capable of being framed in the terms we use.

Descartes theory of knowledge starts with the quest for certainty, for an indubitable starting-point or foundation on the basis alone of which progress is possible. This is eventually found in the celebrated Cogito ergo sum: I think therefore I am. By locating the point of certainty in my own awareness of my own self, Descartes gives a first-person twist to the theory of knowledge that dominated them following centuries in spite of various counter-attacks on behalf of social and public starting-points. The metaphysics associated with this priority is the famous Cartesian dualism, or separation of mind and matter into two different but interacting substances, Descartes rigorously and rightly sees that it takes divine dispensation to certify any relationship between the two realms thus divided, and to prove the reliability of the senses invokes a clear and distinct perception of highly dubious proofs of the existence of a benevolent deity. This has not met general acceptance: as Hume drily puts it, to have recourse to the veracity of the supreme Being, in order to prove the veracity of our senses, is surely making a very unexpected circuit.

In his own time Descartes conception of the entirely separate substance of the mind was recognized to give rise to insoluble problems of the nature of the causal connexion between the two. It also gives rise to the problem, insoluble in its own terms, of other minds. Descartes notorious denial that non-human animals are conscious is a stark illustration of the problem. In his conception of matter Descartes also gives preference to rational cogitation over anything derived from the senses. Since we can conceive of the matter of a ball of wax surviving changes to its sensible qualities, matter is not an empirical concept, but eventually an entirely geometrical one, with extension and motion as its only physical nature. Descartes thought, as reflected in Leibniz, that the qualities of sense experience have no resemblance to qualities of things, so that knowledge of the external world is essentially knowledge of structure rather than of filling. On this basis Descartes erects a remarkable physics. Since matter is in effect the same as extension there can be no empty space or void, since there is no empty space motion is not a question of occupying previously empty space, but is to be thought of in terms of vortices (like the motion of a liquid).

Although the structure of Descartes epistemology, theories of mind, and theories of matter have ben rejected many times, their relentless disarray of the hardest issues, their exemplary clarity, and even their initial plausibility, all contrive to make him the central point of reference for modern philosophy.

The self conceived as Descartes presents it in the first two Meditations: aware only of its own thoughts, and capable of disembodied existence, neither situated in a space nor surrounded by others. This is the pure self of I-ness that we are tempted to imagine as a simple unique thing that make up our essential identity. Descartes view that he could keep hold of this nugget while doubting everything else is criticized by Lichtenberg and Kant, and most subsequent philosophers of mind.

Descartes holds that we do not have any knowledge of any empirical proposition about anything beyond the contents of our own minds. The reason, roughly put, is that there is a legitimate doubt about all such propositions because there is no way to deny justifiably that our senses are being stimulated by some cause (an evil spirit, for example) which is radically different from the objects that we normally think affect our senses.

He also points out, that the senses (sight, hearing, touch, etc., are often unreliable, and it is prudent never to trust entirely those who have deceived us even once, he cited such instances as the straight stick that looks ben t in water, and the square tower that looks round from a distance. This argument of illusion, has not, on the whole, impressed commentators, and some of Descartes contemporaries pointing out that since such errors become known as a result of further sensory information, it cannot be right to cast wholesale doubt on the evidence of the senses. But Descartes regarded the argument from illusion as only the first stage in a softening up process which would lead the mind away from the senses. He admits that there are some cases of sense-base belief about which doubt would be insane, e.g., the belief that I am sitting here by the fire, wearing a winter dressing gown.

Descartes was to realize that there was nothing in this view of nature that could explain or provide a foundation for the mental, or from direct experience as distinctly human. In a mechanistic universe, he said, there is no privileged place or function for mind, and the separation between mind and matter is absolute. Descartes was also convinced, that the immaterial essences that gave form and structure to this universe were coded in geometrical and mathematical ideas, and this insight led him to invent algebraic geometry.

A scientific understanding of these ideas could be derived, said Descartes, with the aid of precise deduction, and also claimed that the contours of physical reality could be laid out in three-dimensional coordinates. Following the publication of Newtons Principia Mathematica in 1687, reductionism and mathematical modelling became the most powerful tools of modern science. And the dream that the entire physical world could be known and mastered through the extension and refinement of mathematical theory became the central feature and guiding principle of scientific knowledge.

Having to its recourse of knowledge, its central questions include the origin of knowledge, the place of experience in generating knowledge, and the place of reason in doing so, the relationship between knowledge and certainty, and between knowledge and the impossibility of error, the possibility of universal scepticism, and the changing forms of knowledge that arise from new conceptualizations of the world. All of these issues link with other central concerns of philosophy, such as the nature of truth and the natures of experience and meaning.

Foundationalism was associated with the ancient Stoics, and in the modern era with Descartes (1596-1650). Who discovered his foundations in the clear and distinct ideas of reason? Its main opponent is Coherentism, or the view that a body of propositions mas be known without a foundation in certainty, but by their interlocking strength, than as a crossword puzzle may be known to have been solved correctly even if each answer, taken individually, admits of uncertainty. Difficulties at this point led the logical passivists to abandon the notion of an epistemological foundation altogether, and to flirt with the coherence theory of truth. It is widely accepted that trying to make the connexion between thought and experience through basic sentences depends on an untenable myth of the given.

Still in spite of these concerns, the problem was, of course, in defining knowledge in terms of true beliefs plus some favoured relations between the believer and the facts that began with Platos view in the Theaetetus, that knowledge is true belief, and some logos. Due of its nonsynthetic epistemology, the enterprising of studying the actual formation of knowledge by human beings, without aspiring to certify those processes as rational, or its proof against scepticism or even apt to yield the truth. Natural epistemology would therefore blend into the psychology of learning and the study of episodes in the history of science. The scope for external or philosophical reflection of the kind that might result in scepticism or its refutation is markedly diminished. Despite the fact that the terms of modernity are so distinguished as exponents of the approach include Aristotle, Hume, and J. S. Mills.

The task of the philosopher of a discipline would then be to reveal the correct method and to unmask counterfeits. Although this belief lay behind much positivist philosophy of science, few philosophers now subscribe to it. It places too well a confidence in the possibility of a purely previous first philosophy, or viewpoint beyond that of the work ones way of practitioners, from which their best efforts can be measured as good or bad. These standpoints now seem that too many philosophers may be too fanciful, that the more modest of tasks are actually adopted at various historical stages of investigation into different areas and with the aim not so much of criticizing, but more of systematization. In the presuppositions of a particular field at a particular classification, there is still a role for local methodological disputes within the community investigators of some phenomenon, with one approach charging that another is unsound or unscientific, but logic and philosophy will not, on the modern view, provide any independent arsenal of weapons for such battles, which often come to seem more like factional recommendations in the ascendancy of a discipline.

This is an approach to the theory of knowledge that sees an important connexion between the growth of knowledge and biological evolution. An evolutionary epistemologist claims that the development of human knowledge processed through some natural selection process, the best example of which is Darwins theory of biological natural selection. There is a widespread misconception that evolution proceeds according to some plan or direct, but it has neither, and the role of chance ensures that its future course will be unpredictable. Random variations in individual organisms create tiny differences in their Darwinian fitness. Some individuals have more offsprings than others, and the characteristics that increased their fitness thereby become more prevalent in future generations. Once upon a time, at least a mutation occurred in a human population in tropical Africa that changed the haemoglobin molecule in a way that provided resistance to malaria. This enormous advantage caused the new gene to spread, with the unfortunate consequence that sickle-cell anaemia came to exist.

Given that chance, it can influence the outcome at each stage: First, in the creation of genetic mutation, second, in whether the bearer lives long enough to show its effects, thirdly, in chance events that influence the individuals actual reproductive success, and fourth, in whether a gene even if favoured in one generation, is, happenstance, eliminated in the next, and finally in the many unpredictable environmental changes that will undoubtedly occur in the history of any group of organisms. As Harvard biologist Stephen Jay Gould has so vividly expressed that process over again, the outcome would surely be different. Not only might there not be humans, there might not even be anything like mammals.

We will often emphasis the elegance of traits shaped by natural selection, but the common idea that nature creates perfection needs to be analysed carefully. The extent to which evolution achieves perfection depends on exactly what you mean. If you mean Does natural selections always take the best path for the long-term welfare of a species? The answer is no. That would require adaption by group selection, and this is, unlikely. If you mean Does natural selection creates every adaption that would be valuable? The answer again, is no. For instance, some kinds of South American monkeys can grasp branches with their tails. The trick would surely also be useful to some African species, but, simply because of bad luck, none have it. Some combination of circumstances started some ancestral South American monkeys using their tails in ways that ultimately led to an ability to grab onto branches, while no such development took place in Africa. Mere usefulness of a trait does not necessitate a means in that what will understandably endure phylogenesis or evolution.

This is an approach to the theory of knowledge that sees an important connexion between the growth of knowledge and biological evolution. An evolutionary epistemologist claims that the development of human knowledge proceeds through some natural selection process, the best example of which is Darwins theory of biological natural selection. The three major components of the model of natural selection are variation selection and retention. According to Darwins theory of natural selection, variations are not pre-designed to do certain functions. Rather, these variations that do useful functions are selected. While those that do not employ of some coordinates in that are regainfully purposed are also, not to any of a selection, as duly influenced of such a selection, that may have responsibilities for the visual aspects of variational intentionally occurs. In the modern theory of evolution, genetic mutations provide the blind variations: Blind in the sense that variations are not influenced by the effects they would have-the likelihood of a mutation is not correlated with the benefits or liabilities that mutation would confer on the organism, the environment provides the filter of selection, and reproduction provides the retention. Fatnesses are achieved because those organisms with features that make them less adapted for survival do not survive in connexion with other organisms in the environment that have features that are better adapted. Evolutionary epistemology applies this blind variation and selective retention model to the growth of scientific knowledge and to human thought processes overall.

The parallel between biological evolution and conceptual or epistemic evolution can be seen as either literal or analogical. The literal version of evolutionary epistemology deeds biological evolution as the main cause of the growth of knowledge. On this view, called the evolution of cognitive mechanic programs, by Bradie (1986) and the Darwinian approach to epistemology by Ruse (1986), that growth of knowledge occurs through blind variation and selective retention because biological natural selection itself is the cause of epistemic variation and selection. The most plausible version of the literal view does not hold that all human beliefs are innate but rather than the mental mechanisms that guide the acquisitions of non-innate beliefs are themselves innately and the result of biological natural selection. Ruse, (1986) demands of a version of literal evolutionary epistemology that he links to sociolology (Rescher, 1990).

On the analogical version of evolutionary epistemology, called the evolution of theories program, by Bradie (1986). The Spenserians approach (after the nineteenth century philosopher Herbert Spencer) by Ruse (1986), the development of human knowledge is governed by a process analogous to biological natural selection, rather than by an instance of the mechanism itself. This version of evolutionary epistemology, introduced and elaborated by Donald Campbell (1974) as well as Karl Popper, sees the [partial] fit between theories and the world as explained by a mental process of trial and error known as epistemic natural selection.

Both versions of evolutionary epistemology are usually taken to be types of naturalized epistemology, because both take some empirical facts as a starting point for their epistemological project. The literal version of evolutionary epistemology begins by accepting evolutionary theory and a materialist approach to the mind and, from these, constructs an account of knowledge and its developments. In contrast, the metaphorical version does not require the truth of biological evolution: It simply draws on biological evolution as a source for the model of natural selection. For this version of evolutionary epistemology to be true, the model of natural selection need only apply to the growth of knowledge, not to the origin and development of species. Crudely put, evolutionary epistemology of the analogical sort could still be true even if Creationism is the correct theory of the origin of species.

Although they do not begin by assuming evolutionary theory, most analogical evolutionary epistemologists are naturalized epistemologists as well, their empirical assumptions, least of mention, implicitly come from psychology and cognitive science, not evolutionary theory. Sometimes, however, evolutionary epistemology is characterized in a seemingly non-naturalistic fashion. Campbell (1974) says that if one is expanding knowledge beyond what one knows, one has no choice but to explore without the benefit of wisdom, i.e., blindly. This, Campbell admits, makes evolutionary epistemology close to being a tautology (and so not naturalistic). Evolutionary epistemology does assert the analytic claim that when expanding ones knowledge beyond what one knows, one must precessed to something that is already known, but, more interestingly, it also makes the synthetic claim that when expanding ones knowledge beyond what one knows, one must proceed by blind variation and selective retention. This claim is synthetic because it can be empirically falsified. The central claim of evolutionary epistemology is synthetic, not analytic. If the central contradictory, which they are not. Campbell is right that evolutionary epistemology does have the analytic feature he mentions, but he is wrong to think that this is a distinguishing feature, since any plausible epistemology has the same analytic feature (Skagestad, 1978).

Two extraordinary issues lie to awaken the literature that involves questions about realism, i.e., What metaphysical commitment does an evolutionary epistemologist have to make? Progress, i.e., according to evolutionary epistemology, does knowledge develop toward a goal? With respect to realism, many evolutionary epistemologists endorse that is called hypothetical realism, a view that combines a version of epistemological scepticism and tentative acceptance of metaphysical realism. With respect to progress, the problem is that biological evolution is not goal-directed, but the growth of human knowledge seems to be. Campbell (1974) worries about the potential dis-analogy here but is willing to bite the stone of conscience and admit that epistemic evolution progress toward a goal (truth) while biologic evolution does not. Many another has argued that evolutionary epistemologists must give up the truth-topic sense of progress because a natural selection model is in essence, is non-teleological, as an alternative, following Kuhn (1970), and embraced in the accompaniment with evolutionary epistemology.

Among the most frequent and serious criticisms leveled against evolutionary epistemology is that the analogical version of the view is false because epistemic variation is not blind (Skagestad, 1978), and (Ruse, 1986) including, (Stein and Lipton, 1990) all have argued, nonetheless, that this objection fails because, while epistemic variation is not random, its constraints come from heuristics that, for the most part, are selective retention. Further, Stein and Lipton come to the conclusion that heuristics are analogous to biological pre-adaptions, evolutionary pre-biological pre-adaptions, evolutionary cursors, such as a half-wing, a precursor to a wing, which have some function other than the function of their descendable structures: The function of descendable structures, the function of their descendable character embodied to its structural foundations, is that of the guidelines of epistemic variation is, on this view, not the source of disanalogy, but the source of a more articulated account of the analogy.

Many evolutionary epistemologists try to combine the literal and the analogical versions (Bradie, 1986, and Stein and Lipton, 1990), saying that those beliefs and cognitive mechanisms, which are innate results from natural selection of the biological sort and those that are innate results from natural selection of the epistemic sort. This is reasonable as long as the two parts of this hybrid view are kept distinct. An analogical version of evolutionary epistemology with biological variation as its only source of blondeness would be a null theory: This would be the case if all our beliefs are innate or if our non-innate beliefs are not the result of blind variation. An appeal to the legitimate way to produce a hybrid version of evolutionary epistemology since doing so trivializes the theory. For similar reasons, such an appeal will not save an analogical version of evolutionary epistemology from arguments to the effect that epistemic variation is blind (Stein and Lipton, 1990).

Although it is a new approach to theory of knowledge, evolutionary epistemology has attracted much attention, primarily because it represents a serious attempt to flesh out a naturalized epistemology by drawing on several disciplines. In science is relevant to understanding the nature and development of knowledge, then evolutionary theory is among the disciplines worth a look. Insofar as evolutionary epistemology looks there, it is an interesting and potentially fruitful epistemological programme.

What makes a belief justified and what makes a true belief knowledge? Thinking that whether a belief deserves one of these appraisals is natural depends on what caused the depicted branch of knowledge to have the belief. In recent decades a number of epistemologists have pursued this plausible idea with a variety of specific proposals. Some causal theories of knowledge have it that a true belief that p is knowledge just in case it has the right causal connexion to the fact that p. Such a criterion can be applied only to cases where the fact that p is a sort that can reach causal relations, as this seems to exclude mathematically and their necessary facts and perhaps any fact expressed by a universal generalization, and proponents of this sort of criterion have usually supposed that it is limited to perceptual representations where knowledge of particular facts about subjects environments.

For example, Armstrong (1973), predetermined that a position held by a belief in the form This perceived object is F is [non-inferential] knowledge if and only if the belief is a completely reliable sign that the perceived object is ‘F’, that is, the fact that the object is ‘F’ contributed to causing the belief and its doing so depended on properties of the believer such that the laws of nature dictated that, for any subject ‘χ’ and perceived object ‘y’, if ‘χ’ has those properties and believed that ‘y’ is ‘F’, then ‘y’ is ‘F’. (Dretske (1981) offers a rather similar account, in terms of the beliefs being caused by a signal received by the perceiver that carries the information that the object is F).

Goldman (1986) has proposed an importantly different causal criterion, namely, that a true belief is knowledge if it is produced by a type of process that is globally and locally reliable. Causing true beliefs is sufficiently high is globally reliable if its propensity. Local reliability has to do with whether the process would have produced a similar but false belief in certain counterfactual situations alternative to the actual situation. This way of marking off true beliefs that are knowledge does not require the fact believed to be causally related to the belief, and so it could in principle apply to knowledge of any kind of truth.

Goldman requires the global reliability of the belief-producing process for the justification of a belief, he requires it also for knowledge because justification is required for knowledge. What he requires for knowledge, but does not require for justification is local reliability. His idea is that a justified true belief is knowledge if the type of process that produced it would not have produced it in any relevant counterfactual situation in which it is false. Its purported theory of relevant alternatives can be viewed as an attempt to provide a more satisfactory response to this tension in our thinking about knowledge. It attempts to characterize knowledge in a way that preserves both our belief that knowledge is an absolute concept and our belief that we have knowledge.

According to the theory, we need to qualify rather than deny the absolute character of knowledge. We should view knowledge as absolute, reactive to certain standards (Dretske, 1981 and Cohen, 1988). That is to say, in order to know a proposition, our evidence need not eliminate all the alternatives to that preposition, rather for us, that we can know our evidence eliminates al the relevant alternatives, where the set of relevant alternatives (a proper subset of the set of all alternatives) is determined by some standard. Moreover, according to the relevant alternatives view, and the standards determining that of the alternatives is raised by the sceptic are not relevant. If this is correct, then the fact that our evidence cannot eliminate the sceptics alternative does not lead to a sceptical result. For knowledge requires only the elimination of the relevant alternatives, so the relevant alternative view preserves in both strands in our thinking about knowledge. Knowledge is an absolute concept, but because the absoluteness is relative to a standard, we can know many things.

The interesting thesis that counts as a causal theory of justification (in the meaning of causal theory intended here) are that: A belief is justified in case it was produced by a type of process that is globally reliable, that is, its propensity to produce true beliefs-that can be defined (to a good approximation) As the proportion of the beliefs it produces (or would produce) that is true is sufficiently great.

This proposal will be adequately specified only when we are told (I) how much of the causal history of a belief counts as part of the process that produced it, (ii) which of the many types to which the process belongs is the type for purposes of assessing its reliability, and (iii) relative to why the world or worlds are the reliability of the process type to be assessed the actual world, the closet worlds containing the case being considered, or something else? Let us look at the answers suggested by Goldman, the leading proponent of a reliabilist account of justification.

(1) Goldman (1979, 1986) takes the relevant belief producing process to include only the proximate causes internal to the believer. So, for instance, when believing that the telephone was ringing the process that produced the belief, for purposes of assessing reliability, includes just the causal chain of neural events from the stimulus in my ears inward and other brain states on which the production of the belief depended: It does not include any events in the telephone, or the sound waves traveling between it and my ears, or any earlier decisions made, that were responsible for being within hearing distance of the telephone at that time. It does seem intuitively plausible of a belief depends should be restricted to internal oneness proximate to the belief. Why? Goldman does not tell us. One answer that some philosophers might give is that it is because a beliefs being justified at a given time can depend only on facts directly accessible to the believers awareness at that time (for, if a believer ought to holds only beliefs that are justified, she can tell at any given time what beliefs would then be justified for her). However, this cannot be Goldmans answer because he wishes to include in the relevantly process neural events that are not directly accessible to consciousness.

(2) Once the reliabilist has told us how to delimit the process producing a belief, he needs to tell us which of the many types to which it belongs is the relevant type. Coincide, for example, the process that produces your believing that you see a book before you. One very broad type to which that process belongs would be specified by coming to a belief as to something one perceives as a result of activation of the nerve endings in some of ones sense-organs. A constricted type, in which that unvarying processes belong would be specified by coming to a belief as to what one sees as a result of activation of the nerve endings in ones retinas. A still narrower type would be given by inserting in the last specification a description of a particular pattern of activation of the retinas particular cells. Which of these or other types to which the token process belongs is the relevant type for determining whether the type of process that produced your belief is reliable?

If we select a type that is too broad, as having the same degree of justification various beliefs that intuitively seem to have different degrees of justification. Thus the broadest type we specified for your belief that you see a book before you apply also to perceptual beliefs where the object seen is far away and seen only briefly is less justified. On the other hand, is we are allowed to select a type that is as narrow as we please, then we make it out that an obviously unjustified but true belief is produced by a reliable type of process. For example, suppose I see a blurred shape through the fog far in a field and unjustifiedly, but correctly, believe that it is a sheep: If we include enough details about my retinal image it may seem that one in specifying the type of the visual process that produced that belief, we can specify a type is likely to have only that one instanced and is therefore 100 percent reliable. Goldman conjectures (1986) that the relevant process type is the narrowest type that is casually operative. Presumably, a feature of the process producing beliefs were causally operatives in producing it just in case some alternative feature instead, but it would not have led to that belief. We need to say some here rather than any, because, for example, when I see an oak or Maple tree, the particular like-minded material bodies of my retinal image is causally clear towards the worked in producing my belief that what is seen as a tree, even though there are alternative shapes, for example, oak or maples, ones that would have produced the same belief.

(3) Should the justification of a belief in a hypothetical, non-actual example turn on the reliability of the belief-producing process in the possible world of the example? That leads to the implausible result in that in a world run by a Cartesian demon-a powerful being who causes the other inhabitants of the world to have rich and careened sets of perceptual and memory impressions that are all illusory the perceptual and memory beliefs of the other inhabitants are all unjustified, for they are produced by processes that are, in that world, quite unreliable. If we say instead that it is the reliability of the processes in the actual world that matters, we get the equally undesired result that if the actual world is a demon world then our perceptual and memory beliefs are all unjustified.

Goldmans solution (1986) is that the reliability of the process types is to be gauged by their performance in normal worlds, that is, worlds consistent with our general beliefs about the world . . . about the sorts of objects, events and changes that occur in it. This gives the intuitively right results for the problem cases just considered, but indicate by inference an implausible proportion of making compensations for alternative tending toward justification. If there are people whose general beliefs about the world are very different from mine, then there may, on this account, be beliefs that I can correctly regard as justified (ones produced by processes that are reliable in what I take to be a normal world) but that they can correctly regard as not justified.

However, these questions about the specifics are dealt with, and there are reasons for questioning the basic idea that the criterion for a beliefs being justified is its being produced by a reliable process. Thus and so, doubt about the sufficiency of the reliabilist criterion is prompted by a sort of example that Goldman himself uses for another purpose. Suppose that being in brain-state (B) always causes one to believe that one is in brained-state (B). Here the reliability of the belief-producing process is perfect, but we can readily imagine circumstances in which a person goes into grain-state B and therefore has the belief in question, though this belief is by no means justified (Goldman, 1979). Doubt about the necessity of the condition arises from the possibility that one might know that one has strong justification for a certain belief and yet that knowledge is not what actually prompts one to believe. For example, I might be well aware that, having read the weather bureaus forecast that it will be much hotter tomorrow. I have ample reason to be confident that it will be hotter tomorrow, but I irrationally refuse to believe it until Wally tells me that he feels in his joints that it will be hotter tomorrow. Here what prompts me to believe or not justify my belief, but my belief is nevertheless justified by my knowledge of the weather bureaus prediction and of its evidential force: I can advert to any disavowable inference that I ought not to be holding the belief. Indeed, given my justification and that there is nothing untoward about the weather bureaus prediction, my belief, if true, can be counted knowledge. This sorts of example raises doubt whether any causal conditions, are it a reliable process or something else, is necessary for either justification or knowledge.

Philosophers and scientists alike, have often held that the simplicity or parsimony of a theory is one reason, all else being equal, to view it as true. This goes beyond the unproblematic idea that simpler theories are easier to work with and gave greater aesthetic appeal.

One theory is more parsimonious than another when it postulates fewer entities, processes, changes or explanatory principles: The simplicity of a theory depends on essentially the same consecrations, though parsimony and simplicity obviously become the same. Demanding clarification of what makes one theory simpler or more parsimonious is plausible than another before the justification of these methodological maxims can be addressed.

If we set this description problem to one side, the major normative problem is as follows: What reason is there to think that simplicity is a sign of truth? Why should we accept a simpler theory instead of its more complex rivals? Newton and Leibniz thought that the answer was to be found in a substantive fact about nature. In Principia, Newton laid down as his first Rule of Reasoning in Philosophy that nature does nothing in vain . . . for Nature is pleased with simplicity and affects not the pomp of superfluous causes. Leibniz hypothesized that the actual world obeys simple laws because Gods’ taste for simplicity influenced his decision about which world to actualize.

The tragedy of the Western mind, described by Koyré, is a direct consequence of the stark Cartesian division between mind and world. We discovered the certain principles of physical reality, said Descartes, not by the prejudices of the senses, but by the light of reason, and which thus possess so great evidence that we cannot doubt of their truth. Since the real, or that which actually exists external to ourselves, was in his view only that which could be represented in the quantitative terms of mathematics, Descartes conclude that all quantitative aspects of reality could be traced to the deceitfulness of the senses.

The most fundamental aspect of the Western intellectual tradition is the assumption that there is a fundamental division between the material and the immaterial world or between the realm of matter and the realm of pure mind or spirit. The metaphysical frame-work based on this assumption is known as ontological dualism. As the word dual implies, the framework is predicated on an ontology, or a conception of the nature of God or Being, that assumes reality has two distinct and separable dimensions. The concept of Being as continuous, immutable, and having a prior or separate existence from the world of change dates from the ancient Greek philosopher Parmenides. The same qualities were associated with the God of the Judeo-Christian tradition, and they were considerably amplified by the role played in theology by Platonic and Neoplatonic philosophy.

Nicolas Copernicus, Galileo, Johannes Kepler, and Isaac Newton were all inheritors of a cultural tradition in which ontological dualism was a primary article of faith. Hence the idealization of the mathematical ideal as a source of communion with God, which dates from Pythagoras, provided a metaphysical foundation for the emerging natural sciences. This explains why, the creators of classical physics believed that doing physics was a form of communion with the geometrical and mathematical forms resident in the perfect mind of God. This view would survive in a modified form in what is now known as Einsteinian epistemology and accounts in no small part for the reluctance of many physicists to accept the epistemology associated with the Copenhagen Interpretation.

At the beginning of the nineteenth century, Pierre-Simon LaPlace, along with a number of other French mathematicians, advanced the view that the science of mechanics constituted a complete view of nature. Since this science, by observing its epistemology, had revealed itself to be the fundamental science, the hypothesis of God was, they concluded, entirely unnecessary.

LaPlace is recognized for eliminating not only the theological component of classical physics but the entire metaphysical component as well. The epistemology of science requires, he said, that we proceed by inductive generalizations from observed facts to hypotheses that are tested by observed conformity of the phenomena. What was unique about LaPlaces view of hypotheses was his insistence that we cannot attribute reality to them. Although concepts like force, mass, motion, cause, and laws are obviously present in classical physics, they exist in LaPlaces view only as quantities. Physics is concerned, he argued, with quantities that we associate as a matter of convenience with concepts, and the truth about nature are only the quantities.

As this view of hypotheses and the truth of nature as quantities was extended in the nineteenth century to a mathematical description of phenomena like heat, light, electricity, and magnetism. LaPlaces assumptions about the actual character of scientific truth seemed correct. This progress suggested that if we could remove all thoughts about the nature of or the source of phenomena, the pursuit of strictly quantitative concepts would bring us to a complete description of all aspects of physical reality. Subsequently, figures like Comte, Kirchhoff, Hertz, and Poincaré developed a program for the study of nature hat was quite different from that of the original creators of classical physics.

The seventeenth-century view of physics as a philosophy of nature or as natural philosophy was displaced by the view of physics as an autonomous science that was the science of nature. This view, which was premised on the doctrine of positivism, promised to subsume all of nature with a mathematical analysis of entities in motion and claimed that the true understanding of nature was revealed only in the mathematical description. Since the doctrine of positivism assumes that the knowledge we call physics resides only in the mathematical formalism of physical theory, it disallows the prospect that the vision of physical reality revealed in physical theory can have any other meaning. In the history of science, the irony is that positivism, which was intended to banish metaphysical concerns from the domain of science, served to perpetuate a seventeenth-century metaphysical assumption about the relationship between physical reality and physical theory.

Epistemology since Hume and Kant has drawn back from this theological underpinning. Indeed, the very idea that nature is simple (or uniform) has come in for a critique. The view has taken hold that a preference for simple and parsimonious hypotheses is purely methodological: It is constitutive of the attitude we call scientific and makes no substantive assumption about the way the world is.

A variety of otherwise diverse twentieth-century philosophers of science have attempted, in different ways, to flesh out this position. Two examples must suffice here: Hesse (1969) as, for summaries of other proposals. Popper (1959) holds that scientists should prefer highly falsifiable (improbable) theories: He tries to show that simpler theories are more falsifiable, also Quine (1966), in contrast, sees a virtue in theories that are highly probable, he argues for a general connexion between simplicity and high probability.

Both these proposals are global. They attempt to explain why simplicity should be part of the scientific method in a way that spans all scientific subject matters. No assumption about the details of any particular scientific problem serves as a premiss in Popper or Quine's arguments.

Newton and Leibniz thought that the justification of parsimony and simplicity flows from the hand of God: Popper and Quine try to justify these methodologically median of importance is without assuming anything substantive about the way the world is. In spite of these differences in approach, they have something in common. They assume that all users of parsimony and simplicity in the separate sciences can be encompassed in a single justifying argument. That recent developments in confirmation theory suggest that this assumption should be scrutinized. Good (1983) and Rosenkrantz (1977) has emphasized the role of auxiliary assumptions in mediating the connexion between hypotheses and observations. Whether a hypothesis is well supported by some observations, or whether one hypothesis is better supported than another by those observations, crucially depends on empirical background assumptions about the inference problem here. The same view applies to the idea of prior probability (or, prior plausibility). In of a single hypo-physical science if chosen as an alternative to another even though they are equally supported by current observations, this must be due to an empirical background assumption.

Principles of parsimony and simplicity mediate the epistemic connexion between hypotheses and observations. Perhaps these principles are able to do this because they are surrogates for an empirical background theory. It is not that there is one background theory presupposed by every appeal to parsimony; This has the quantifier order backwards. Rather, the suggestion is that each parsimony argument is justified only to each degree that it reflects an empirical background theory about the subjective matter. On this theory is brought out into the open, but the principle of parsimony is entirely dispensable (Sober, 1988).

This local approach to the principles of parsimony and simplicity resurrects the idea that they make sense only if the world is one way rather than another. It rejects the idea that these maxims are purely methodological. How defensible this point of view is, will depend on detailed case studies of scientific hypothesis evaluation and on further developments in the theory of scientific inference.

It is usually not found of one and the same that, an inference is a (perhaps very complex) act of thought by virtue of which act (1) I pass from a set of one or more propositions or statements to a proposition or statement and (2) it appears that the latter are true if the former is or are. This psychological characterization has occurred over a wider summation of literature under more lesser than inessential variations. Desiring a better characterization of inference is natural. Yet attempts to do so by constructing a fuller psychological explanation fail to comprehend the grounds on which inference will be objectively valid-A point elaborately made by Gottlob Frége. Attempts to understand the nature of inference through the device of the representation of inference by formal-logical calculations or derivations better (1) leave us puzzled about the relation of formal-logical derivations to the informal inferences they are supposedly to represent or reconstruct, and (2) leaves us worried about the sense of such formal derivations. Are these derivations inference? Are not informal inferences needed in order to apply the rules governing the constructions of formal derivations (inferring that this operation is an application of that formal rule)? These are concerns cultivated by, for example, Wittgenstein.

Coming up with an adequate characterized inferences, and even working out what would count as a very adequate characterization here is demandingly by no means nearly some resolved philosophical problem.

Traditionally, a proposition that is not a conditional, as with the affirmative and negative, modern opinion is wary of the distinction, since what appears categorical may vary with the choice of a primitive vocabulary and notation. Apparently categorical propositions may also turn out to be disguised conditionals: X is intelligent (categorical?) Equivalent, if X is given a range of tasks, she does them better than many people (conditional?). The problem is not merely one of classification, since deep metaphysical questions arise when facts that seem to be categorical and therefore solid, come to seem by contrast conditional, or purely hypothetical or potential.

Its condition of some classified necessity is so proven sufficient that if p is a necessary condition of q, then q cannot be true unless p; is true? If p is a sufficient condition, thus steering well is a necessary condition of driving in a satisfactory manner, but it is not sufficient, for one can steer well but drive badly for other reasons. Confusion may result if the distinction is not heeded. For example, the statement that A causes B may be interpreted to mean that A is itself a sufficient condition for B, or that it is only a necessary condition fort B, or perhaps a necessary parts of a total sufficient condition. Lists of conditions to be met for satisfying some administrative or legal requirement frequently attempt to give individually necessary and jointly sufficient sets of conditions.

What is more that if any proposition of the form if p then q. The condition hypothesized, p. Is called the antecedent of the conditionals, and q, the consequent? Various kinds of conditional have been distinguished. Its weakest is that of material implication, merely telling that either not-p, or q. Stronger conditionals include elements of modality, corresponding to the thought that if p is truer then q must be true. Ordinary language is very flexible in its use of the conditional form, and there is controversy whether conditionals are better treated semantically, yielding differently finds of conditionals with different meanings, or pragmatically, in which case there should be one basic meaning with surface differences arising from other implicatures.

It follows from the definition of strict implication that a necessary proposition is strictly implied by any proposition, and that an impossible proposition strictly implies any proposition. If strict implication corresponds to q follows from p, then this means that a necessary proposition follows from anything at all, and anything at all follows from an impossible proposition. This is a problem if we wish to distinguish between valid and invalid arguments with necessary conclusions or impossible premises.

The Humean problem of induction is that if we would suppose that there is some property ‘A’ concerning and observational or an experimental situation, and that out of a large number of observed instances of ‘A’, some fraction m/n (possibly equal to 1) has also been instances of some logically independent property ‘B’. Suppose further that the background proportionate circumstances not specified in these descriptions have been varied to a substantial degree and that there is no collateral information available concerning the frequency of ‘B’s’ among ‘A’s’ or concerning causal or nomologically connections between instances of ‘A’ and instances of ‘B’.

In this situation, an enumerative or instantial induction inference would move rights from the premise, that m/n of observed ‘A’s’ are ‘B’s’ to the conclusion that approximately m/n of all ‘A’s’ are ‘B’s’. (The usual probability qualification will be assumed to apply to the inference, rather than being part of the conclusion.) Here the class of ‘A’s’ should be taken to include not only unobserved ‘A’s’ and future ‘A’s’, but also possible or hypothetical ‘A’s’ (an alternative conclusion would concern the probability or likelihood of the adjacently observed ‘A’ being a ‘B’).

The traditional or Humean problem of induction, often referred to simply as the problem of induction, is the problem of whether and why inferences that fit this schema should be considered rationally acceptable or justified from an epistemic or cognitive standpoint, i.e., whether and why reasoning in this way is likely to lead to true claims about the world. Is there any sort of argument or rationale that can be offered for thinking that conclusions reached in this way are likely to be true in the corresponding premisses is true - or even that their chances of truth are significantly enhanced?

Humes discussion of this issue deals explicitly only with cases where all observed ‘A’s’ are ‘B’s’ and his argument applies just as well to the more general case. His conclusion is entirely negative and sceptical: Inductive inferences are not rationally justified, but are instead the result of an essentially a-rational process, custom or habit. Hume (1711-76) challenges the proponent of induction to supply a cogent ligne of reasoning that leads from an inductive premise to the corresponding conclusion and offers an extremely influential argument in the form of a dilemma (a few times referred to as Humes fork), that either our actions are determined, in which case we are not responsible for them, or they are the result of random events, under which case we are also not responsible for them.

Such reasoning would, he argues, have to be either deductively demonstrative reasoning in the concerning relations of ideas or experimental, i.e., empirical, that reasoning concerning matters of fact or existence. It cannot be the former, because all demonstrative reasoning relies on the avoidance of contradiction, and it is not a contradiction to suppose that the course of nature may change, that an order that was observed in the past and not of its continuing against the future: But it cannot be, as the latter, since any empirical argument would appeal to the success of such reasoning about an experience, and the justifiability of generalizing from experience are precisely what is at issue-so that any such appeal would be question-begging. Hence, Hume concludes that there can be no such reasoning (1748).

An alternative version of the problem may be obtained by formulating it with reference to the so-called Principle of Induction, which says roughly that the future will resemble the past or, somewhat better, that unobserved cases will resemble observed cases. An inductive argument may be viewed as enthymematic, with this principle serving as a supposed premiss, in which case the issue is obviously how such a premiss can be justified. Humes argument is then that no such justification is possible: The principle cannot be justified a prior because having possession of been true in experiences without obviously begging the question is not contradictory to have possession of been true in experiences without obviously begging the question.

The predominant recent responses to the problem of induction, at least in the analytic tradition, in effect accept the main conclusion of Humes argument, namely, that inductive inferences cannot be justified in the sense of showing that the conclusion of such an inference is likely to be true if the premise is true, and thus attempt to find another sort of justification for induction. Such responses fall into two main categories: (I) Pragmatic justifications or vindications of induction, mainly developed by Hans Reichenbach (1891-1953), and (ii) ordinary language justifications of induction, whose most important proponent is Frederick, Peter Strawson (1919-). In contrast, some philosophers still attempt to reject Humes dilemma by arguing either (iii) That, contrary to appearances, induction can be inductively justified without vicious circularity, or (iv) that an anticipatory justification of induction is possible after all. In that:

(1) Reichenbachs view is that induction is best regarded, not as a form of inference, but rather as a method for arriving at posits regarding, i.e., the proportion of As remain additionally of B’s. Such a posit is not a claim asserted to be true, but is instead an intellectual wager analogous to a bet made by a gambler. Understood in this way, the inductive method says that one should posit that the observed proportion is, within some measure of an approximation, the true proportion and then continually correct that initial posit as new information comes in.

The gamblers bet is normally an appraised posit, i.e., he knows the chances or odds that the outcome on which he bets will actually occur. In contrast, the inductive bet is a blind posit: We do not know the chances that it will succeed or even that success is that it will succeed or even that success is possible. What we are gambling on when we make such a bet is the value of a certain proportion in the independent world, which Reichenbach construes as the limit of the observed proportion as the number of cases increases to infinity. Nevertheless, we have no way of knowing that there are even such a limit, and no way of knowing that the proportion of As are in addition of B’s converges in the end on some stable value than varying at random. If we cannot know that this limit exists, then we obviously cannot know that we have any definite chance of finding it.

What we can know, according to Reichenbach, is that if there is a truth of this sort to be found, the inductive method will eventually find it. That this is so is an analytic consequence of Reichenbachs account of what it is for such a limit to exist. The only way that the inductive method of making an initial posit and then refining it in light of new observations can fail eventually to arrive at the true proportion is if the series of observed proportions never converges on any stable value, which means that there is no truth to be found pertaining the proportion of As additionally constitute B’s. Thus, induction is justified, not by showing that it will succeed or indeed, that it has any definite likelihood of success, but only by showing that it will succeed if success is possible. Reichenbachs claim is that no more than this can be established for any method, and hence that induction gives us our best chance for success, our best gamble in a situation where there is no alternative to gambling.

This pragmatic response to the problem of induction faces several serious problems. First, there are indefinitely many other methods for arriving at posits for which the same sort of defence can be given-methods that yield the same result as the inductive method over time but differ arbitrarily before long. Despite the efforts of others, it is unclear that there is any satisfactory way to exclude such alternatives, in order to avoid the result that any arbitrarily chosen short-term posit is just as reasonable as the inductive posit. Second, even if there is a truth of the requisite sort to be found, the inductive method is only guaranteed to find it or even to come within any specifiable distance of it in the indefinite long run. All the same, any actual application of inductive results always takes place in the presence to the future eventful states in making the relevance of the pragmatic justification to actual practice uncertainly. Third, and most important, it needs to be emphasized that Reichenbachs response to the problem simply accepts the claim of the Humean sceptic that an inductive premise never provides the slightest reason for thinking that the corresponding inductive conclusion is true. Reichenbach himself is quite candid on this point, but this does not alleviate the intuitive implausibility of saying that we have no more reason for thinking that our scientific and commonsense conclusions that result in the induction of it . . . is true than, to use Reichenbachs own analogy (1949), a blind man wandering in the mountains who feels an apparent trail with his stick has for thinking that following it will lead him to safety.

An approach to induction resembling Reichenbachs claiming in that those particular inductive conclusions are posits or conjectures, than the conclusions of cogent inferences, is offered by Popper. However, Poppers view is even more overtly sceptical: It amounts to saying that all that can ever be said in favours of the truth of an inductive claim is that the claim has been tested and not yet been shown to be false.

(2) The ordinary language response to the problem of induction has been advocated by many philosophers, none the less, Strawson claims that the question whether induction is justified or reasonable makes sense only if it tacitly involves the demand that inductive reasoning meet the standards appropriate to deductive reasoning, i.e., that the inductive conclusions are shown to follow deductively from the inductive assumption. Such a demand cannot, of course, be met, but only because it is illegitimate: Inductive and deductive reasons are simply fundamentally different kinds of reasoning, each possessing its own autonomous standards, and there is no reason to demand or expect that one of these kinds meet the standards of the other. Whereas, if induction is assessed by inductive standards, the only ones that are appropriate, then it is obviously justified.

The problem here is to understand to what this allegedly obvious justification of an induction amount. In his main discussion of the point (1952), Strawson claims that it is an analytic true statement that believing it a conclusion for which there is strong evidence is reasonable and an analytic truth that inductive evidence of the sort captured by the schema presented earlier constitutes strong evidence for the corresponding inductive conclusion, thus, apparently yielding the analytic conclusion that believing it a conclusion for which there is inductive evidence is reasonable. Nevertheless, he also admits, indeed insists, that the claim that inductive conclusions will be true in the future is contingent, empirical, and may turn out to be false (1952). Thus, the notion of reasonable belief and the correlative notion of strong evidence must apparently be understood in ways that have nothing to do with likelihood of truth, presumably by appeal to the standard of reasonableness and strength of evidence that are accepted by the community and are embodied in ordinary usage.

Understood in this way, Strawsons response to the problem of inductive reasoning does not speak to the central issue raised by Humean scepticism: The issue of whether the conclusions of inductive arguments are likely to be true. It amounts to saying merely that if we reason in this way, we can correctly call ourselves reasonable and our evidence strong, according to our accepted community standards. Nevertheless, to the undersealing of issue of wether following these standards is a good way to find the truth, the ordinary language response appears to have nothing to say.

(3) The main attempts to show that induction can be justified inductively have concentrated on showing that such as a defence can avoid circularity. Skyrms (1975) formulate, perhaps the clearest version of this general strategy. The basic idea is to distinguish different levels of inductive argument: A first level in which induction is applied to things other than arguments: A second level in which it is applied to arguments at the first level, arguing that they have been observed to succeed so far and hence are likely to succeed in general: A third level in which it is applied in the same way to arguments at the second level, and so on. Circularity is allegedly avoided by treating each of these levels as autonomous and justifying the argument at each level by appeal to an argument at the next level.

One problem with this sort of move is that even if circularity is avoided, the movement to Higher and Higher levels will clearly eventually fail simply for lack of evidence: A level will reach at which there have been enough successful inductive arguments to provide a basis for inductive justification at the next Higher level, and if this is so, then the whole series of justifications collapses. A more fundamental difficulty is that the epistemological significance of the distinction between levels is obscure. If the issue is whether reasoning in accord with the original schema offered above ever provides a good reason for thinking that the conclusion is likely to be true, then it still seems question-begging, even if not flatly circular, to answer this question by appeal to anther argument of the same form.

(4) The idea that induction can be justified on a pure priori basis is in one way the most natural response of all: It alone treats an inductive argument as an independently cogent piece of reasoning whose conclusion can be seen rationally to follow, although perhaps only with probability from its premise. Such an approach has, however, only rarely been advocated (Russell, 19132 and BonJour, 1986), and is widely thought to be clearly and demonstrably hopeless.

Many on the reasons for this pessimistic view depend on general epistemological theses about the possible or nature of anticipatory cognition. Thus if, as Quine alleges, there is no a prior justification of any kind, then obviously a prior justification for induction is ruled out. Or if, as more moderate empiricists have in claiming some preexistent knowledge should be analytic, then again a prevenient justification for induction seems to be precluded, since the claim that if an inductive premise is truer, then the conclusion is likely to be true does not fit the standard conceptions of analyticity. A consideration of these matters is beyond the scope of the present spoken exchange.

There are, however, two more specific and quite influential reasons for thinking that an early approach is impossible that can be briefly considered, first, there is the assumption, originating in Hume, but since adopted by very many of others, that a move forward in the defence of induction would have to involve turning induction into deduction, i.e., showing, per impossible, that the inductive conclusion follows deductively from the premise, so that it is a formal contradiction to accept the latter and deny the former. However, it is unclear why a prior approach need be committed to anything this strong. It would be enough if it could be argued that it is deductively unlikely that such a premise is true and corresponding conclusion false.

Second, Reichenbach defends his view that pragmatic justification is the best that is possible by pointing out that a completely chaotic world in which there is simply not true conclusion to be found as to the proportion of As in addition that occur of, but B’s is neither impossible nor unlikely from a purely a prior standpoint, the suggestion being that therefore there can be no a prior reason for thinking that such a conclusion is true. Nevertheless, there is still a substring way in laying that a chaotic world is a prior neither impossible nor unlikely without any further evidence does not show that such a world os not a prior unlikely and a world containing such-and-such regularity might anticipatorially be somewhat likely in relation to an occurrence of a long running pattern of evidence in which a certain stable proportion of observed As are B’s ~. An occurrence, it might be claimed, that would be highly unlikely in a chaotic world (BonJour, 1986).

Goodmans new riddle of induction purports that we suppose that before some specific time t (perhaps the year 2000) we observe a larger number of emeralds (property A) and find them all to be green (property B). We proceed to reason inductively and conclude that all emeralds are green Goodman points out, however, that we could have drawn a quite different conclusion from the same evidence. If we define the term stuff to mean green if examined before t and blue examined after t ʹ, then all of our observed emeralds will also be gruing. A parallel inductive argument will yield the conclusion that all emeralds are gruing, and hence that all those examined after the year 2000 will be blue. Presumably the first of these concisions is genuinely supported by our observations and the second is not. Nevertheless, the problem is to say why this is so and to impose some further restriction upon inductive reasoning that will permit the first argument and exclude the second.

The obvious alternative suggestion is that stuff. Similar predicates do not correspond to genuine, purely qualitative properties in the way that green and blueness does, and that this is why inductive arguments involving them are unacceptable. Goodman, however, claims to be unable to make clear sense of this suggestion, pointing out that the relations of formal desirability are perfectly symmetrical: Stuff may be defined in terms if, green and blue, but green an equally well be defined in terms of stuff and green (blue if examined before t and green if examined after t).

The stuff that has been recognized from its complicated and most puzzling of named paradoxes that only demonstrate the importance of categorization, in that sometimes it is itemized as gruing, if examined of a presence to the future, before future time t and green, or not so examined and blue. Even though all emeralds in our evidence class stuff, we ought must infer that all emeralds are gruing. For stuff is unprojectible, and cannot transmit credibility from known to unknown cases. Only projectable predicates are right for induction. Goodman considers entrenchment the key to projectibility having a long history of successful protection, stuff is entrenched, lacking such a history, stuff is not. A hypothesis is projectable, Goodman suggests, only if its predicates (or suitable related ones) are much better entrenched than its rivalrous past successes that do not assume future ones. Induction remains a risky business. The rationale for favoring entrenched predicates is pragmatic. Of the possible projections from our evidence class, the one that fits with past practices enables us to utilize our cognitive resources best. Its prospects of being true are worse than its competitors and its cognitive utility is greater.

So, to a better understanding of induction we should then literize its term for which is most widely used for any process of reasoning that takes us from empirical premises to empirical conclusions supported by the premises, but not deductively entailed by them. Inductive arguments are therefore kinds of applicative arguments, in which something beyond the content of the premise is inferred as probable or supported by them. Induction is, however, commonly distinguished from arguments to theoretical explanations, which share this applicative character, by being confined to inferences in which he conclusion involves the same properties or relations as the premises. The central example is induction by simple enumeration, where from premises telling that Fa, Fb, Fc . . . where ‘a’, ‘b’, ‘C’s’, are all of some kind ‘G’, it is inferred that ‘G’s’ from outside the sample, such as future ‘G’s’, will be ‘F’, or perhaps that all ‘G’s’ are ‘F’. In this, which and the other persons deceive them, children may infer that everyone is a deceiver: Different, but similar inferences of a property by some object to the same objects future possession of the same property, or from the constancy of some law-like pattern in events and states of affairs ti its future constancy. All objects we know of attract each other with a force inversely proportional to the square of the distance between them, so perhaps they all do so, and will always do so.

The rational basis of any inference was challenged by Hume, who believed that induction presupposed belief in the uniformity of nature, but that this belief has no defence in reason, and merely reflected a habit or custom of the mind. Hume was not therefore sceptical about the role of reason in either explaining it or justifying it. Trying to answer Hume and to show that there is something rationally compelling about the inference referred to as the problem of induction. It is widely recognized that any rational defence of induction will have to partition well-behaved properties for which the inference is plausible (often called projectable properties) from badly behaved ones, for which it is not. It is also recognized that actual inductive habits are more complex than those of similar enumeration, and that both common sense and science pay attention to such giving factors as variations within the sample giving us the evidence, the application of ancillary beliefs about the order of nature, and so on.

Nevertheless, the fundamental problem remains that and experience condition by application show us only events occurring within a very restricted part of a vast spatial and temporal order about which we then come to believe things.

Uncompounded by its belonging of a confirmation theory finding of the measure to which evidence supports a theory fully formalized confirmation theory would dictate the degree of confidence that a rational investigator might have in a theory, given some-body of evidence. The grandfather of confirmation theory is Gottfried Leibniz (1646-1718), who believed that a logically transparent language of science would be able to resolve all disputes. In the 20th century a fully formal confirmation theory was a main goal of the logical positivist, since without it the central concept of verification by empirical evidence itself remains distressingly unscientific. The principal developments were due to Rudolf Carnap (1891-1970), culminating in his Logical Foundations of Probability (1950). Carnaps idea was that the measure necessitated would be the proportion of logically possible states of affairs in which the theory and the evidence both hold, compared ti the number in which the evidence itself holds that the probability of a preposition, relative to some evidence, is a proportion of the range of possibilities under which the proposition is true, compared to the total range of possibilities left by the evidence. The difficulty with the theory lies in identifying sets of possibilities so that they admit of measurement. It therefore demands that we can put a measure on the range of possibilities consistent with theory and evidence, compared with the range consistent with the evidence alone.

Among the obstacles the enterprise meets, is the fact that while evidence covers only a finite range of data, the hypotheses of science may cover an infinite range. In addition, confirmation proves to vary with the language in which the science is couched, and the Carnapian programme has difficulty in separating genuinely confirming variety of evidence from less compelling repetition of the same experiment. Confirmation also proved to be susceptible to acute paradoxes. Finally, scientific judgement seems to depend on such intangible factors as the problems facing rival theories, and most workers have come to stress instead the historically situated scene of what would appear as a plausible distinction of a scientific knowledge at a given time.

Arose to the paradox of which when a set of apparent incontrovertible premises is given to unacceptable or contradictory conclusions. To solve a paradox will involve showing either that there is a hidden flaw in the premises, or that the reasoning is erroneous, or that the apparently unacceptable conclusion can, in fact, be tolerated. Paradoxes are therefore important in philosophy, for until one is solved it shows that there is something about our reasoning and our concepts that we do not understand. What is more, and somewhat loosely, a paradox is a compelling argument from unacceptable premises to an unacceptable conclusion: More strictly speaking, a paradox is specified to be a sentence that is true if and only if it is false. A characterized objection lesson of it would be: The displayed sentence is false.

Seeing that this sentence is false if true is easy, and true if false, a paradox, in either of the senses distinguished, presents an important philosophical challenger. Epistemologists are especially concerned with various paradoxes having to do with knowledge and belief. In other words, for example, the Knower paradox is an argument that begins with apparently impeccable premisses about the concepts of knowledge and inference and derives an explicit contradiction. The origin of the reasoning is the surprise examination paradox: A teacher announces that there will be a surprise examination next week. A clever student argues that this is impossible. The test cannot be on Friday, the last day of the week, because it would not be a surprise. We would know the day of the test on Thursday evening. This means we can also rule out Thursday. For after we learn that no test has been given by Wednesday, we would know the test is on Thursday or Friday -and would already know that it s not on Friday and would already know that it is not on Friday by the previous reasoning. The remaining days can be eliminated in the same manner.

This puzzle has over a dozen variants. The first was probably invented by the Swedish mathematician Lennard Ekbon in 1943. Although the first few commentators regarded the reverse elimination argument as cogent, every writer on the subject since 1950 agrees that the argument is unsound. The controversy has been over the proper diagnosis of the flaw.

Initial analyses of the subjects argument tried to lay the blame on a simple equivocation. Their failure led to more sophisticated diagnoses. The general format has been an assimilation to better-known paradoxes. One tradition casts the surprise examination paradox as a self-referential problem, as fundamentally akin to the Liar, the paradox of the Knower, or Gödels incompleteness theorem. That in of itself, says enough that Kaplan and Montague (1960) distilled the following self-referential paradox, the Knower. Consider the sentence: (S) The negation of this sentence is known (to be true).

Suppose that (S) is true. Then its negation is known and hence true. However, if its negation is true, then (S) must be false. Therefore (s) is false, or what is the name, the negation of (S) is true.

This paradox and its accompanying reasoning are strongly reminiscent of the Lair Paradox that (in one version) begins by considering a sentence This sentence is false and derives a contradiction. Versions of both arguments using axiomatic formulations of arithmetic and Gödel-numbers to achieve the effect of self-reference yields important meta-theorems about what can be expressed in such systems. Roughly these are to the effect that no predicates definable in the formalized arithmetic can have the properties we demand of truth (Tarskis Theorem) or of knowledge (Montague, 1963).

These meta-theorems still leave us; with the problem that if we suppose that we add of these formalized languages predicates intended to express the concept of knowledge (or truth) and inference - as one mighty does if a logic of these concepts is desired. Then the sentence expressing the leading principles of the Knower Paradox will be true.

Explicitly, the assumption about knowledge and inferences are:

(1) If sentences A are known, then a.

(2) (1) is known?

(3) If B is correctly inferred from A, and A is known, then B is known.

To give an absolutely explicit t derivation of the paradox by applying these principles to (S), we must add (contingent) assumptions to the effect that certain inferences have been done. Still, as we go through the argument of the Knower, these inferences are done. Even if we can somehow restrict such principles and construct a consistent formal logic of knowledge and inference, the paradoxical argument as expressed in the natural language still demands some explanation.

The usual proposals for dealing with the Liar often have their analogues for the Knower, e.g., that there is something wrong with a self-reference or that knowledge (or truth) is properly a predicate of propositions and not of sentences. The relies that show that some of these are not adequate are often parallel to those for the Liar paradox. In addition, on e c an try here what seems to be an adequate solution for the Surprise Examination Paradox, namely the observation that new knowledge can drive out knowledge, but this does not seem to work on the Knower (Anderson, 1983).

There are a number of paradoxes of the Liar family. The simplest example is the sentence This sentence is false, which must be false if it is true, and true if it is false. One suggestion is that the sentence fails to say anything, but sentences that fail to say anything are at least not true. In fact case, we consider to sentences This sentence is not true, which, if it fails to say anything is not true, and hence (this kind of reasoning is sometimes called the strengthened Liar). Other versions of the Liar introduce pairs of sentences, as in a slogan on the front of a T-shirt saying This sentence on the back of this T-shirt is false, and one on the back saying The sentence on the front of this T-shirt is true. It is clear that each sentence individually is well formed, and were it not for the other, might have said something true. So any attempt to dismiss the paradox by settling in that of the sentence involved are meaningless will face problems.

Even so, the two approaches that have some hope of adequately dealing with this paradox is hierarchy solutions and truth-value gap solutions. According to the first, knowledge is structured into levels. It is argued that there be one-careened notion expressed by the verb; knows, but rather a whole series of notions, of the knowable knows, and so on (perhaps into transfinite), stated ion terms of predicate expressing such ramified concepts and properly restricted, (1)-(3) lead to no contradictions. The main objections to this procedure are that the meaning of these levels has not been adequately explained and that the idea of such subscripts, even implicit, in a natural language is highly counterintuitive the truth-value gap solution takes sentences such as (S) to lack truth-value. They are neither true nor false, but they do not express propositions. This defeats a crucial step in the reasoning used in the derivation of the paradoxes. Kripler (1986) has developed this approach in connexion with the Liar and Asher and Kamp (1986) has worked out some details of a parallel solution to the Knower. The principal objection is that strengthened or super versions of the paradoxes tend to reappear when the solution itself is stated.

Since the paradoxical deduction uses only the properties (1)-(3) and since the argument is formally valid, any notion that satisfy these conditions will lead to a paradox. Thus, Grim (1988) notes that this may be read as is known by an omniscient God and concludes that there is no careened single notion of omniscience. Thomason (1980) observes that with some different conditions, analogous reasoning about belief can lead to paradoxical consequence.

Overall, it looks as if we should conclude that knowledge and truth are ultimately intrinsically stratified concepts. It would seem that we must simply accept the fact that these (and similar) concepts cannot be assigned of any-one fixed, finite or infinite. Still, the meaning of this idea certainly needs further clarification.

Its paradox arises when a set of apparently incontrovertible premises gives unacceptable or contradictory conclusions, to solve a paradox will involve showing either that there is a hidden flaw in the premises, or that the reasoning is erroneous, or that the apparently unacceptable conclusion can, in fact, be tolerated. Paradoxes are therefore important in philosophy, for until one is solved its shows that there is something about our reasoning and of concepts that we do not understand. Famous families of paradoxes include the semantic paradoxes and Zenos paradoxes. Art the beginning of the 20th century, paradox and other set-theoretical paradoxes led to the complete overhaul of the foundations of set theory, while the Sorites paradox has lead to the investigations of the semantics of vagueness and fuzzy logics.

It is, however, to what extent can analysis be informative? This is the question that gives a riser to what philosophers has traditionally called the paradox of analysis. Thus, consider the following proposition:

(1) To be an instance of knowledge is to be an instance of justified true belief not essentially grounded in any falsehood. (1) If true, illustrates an important type of philosophical analysis. For convenience of exposition, I will assume (1) is a correct analysis. The paradox arises from the fact that if the concept of justified true belief not been essentially grounded in any falsification is the analysand of the concept of knowledge, it would seem that they are the same concept and hence that: (2) To be an instance of knowledge is to be as an instance of knowledge and would have to be the same propositions as (1). But then how can (1) be informative when (2) is not? This is what is called the first paradox of analysis. Classical writings on analysis suggests a second paradoxical analysis (Moore, 1942).

(3) An analysis of the concept of being a brother is that to be a

brother is to be a male sibling. If (3) is true, it would seem that the concept of being a brother would have to be the same concept as the concept of being a male sibling and tat:

(4) An analysis of the concept of being a brother is that to be a brother is to be a brother

would also have to be true and in fact, would have to be the same proposition as (3?). Yet (3) is true and (4) is false.

Both these paradoxes rest upon the assumptions that analysis is a relation between concepts, than one involving entity of other sorts, such as linguistic expressions, and tat in a true analysis, analysand and analysandum are the same concept. Both these assumptions are explicit in Moore, but some of Moores remarks hint at a solution to that of another statement of an analysis is a statement partly about the concept involved and partly about the verbal expressions used to express it. He says he thinks a solution of this sort is bound to be right, but fails to suggest one because he cannot see a way in which the analysis can be even partly about the expression (Moore, 1942).

Elsewhere, of such ways, as a solution to the second paradox, to which is explicating (3) as: (5) - An analysis is given by saying that the verbal expression ‘χ’ is a brother expresses the same concept as is expressed by the conjunction of the verbal expressions ‘χ’ is male when used to express the concept of being male and ‘χ’ is a sibling when used to express the concept of being a sibling. (Ackerman, 1990). An important point about (5) is as follows. Stripped of its philosophical jargon (analysis, concept, ‘χ’ is a . . . ’), (5) seems to state the sort of information generally stated in a definition of the verbal expression brother in terms of the verbal expressions male and sibling, where this definition is designed to draw upon listeners antecedent understanding of the verbal expression male and sibling, and thus, to tell listeners what the verbal expression brother really means, instead of merely providing the information that two verbal expressions are synonymous without specifying the meaning of either one. Thus, its solution to the second paradox seems to make the sort of analysis that gives rise to this paradox is a matter of specifying the meaning of a verbal expression in terms of separate verbal expressions already understood and saying how the meanings of these separate, already-understood verbal expressions are combined. This corresponds to Moores intuitive requirement that an analysis should both specify the constituent concepts of the analysandum and tell how they are combined, but is this all there is to philosophical analysis?

We must note that, in addition too there being two paradoxes of analysis, there is two types of analyses that are relevant here. (There are also other types of analysis, such as reformatory analysis, where the analysand are intended to improve on and replace the analysandum. But since reformatory analysis involves no commitment to conceptual identity between analysand and analysandum, reformatory analysis does not generate a paradox of analysis and so will not concern us here.) One way to recognize the difference between the two types of analysis concerning us here is to focus on the difference between the two paradoxes. This can be done by means of the Frége-inspired sense-individuation condition, which is the condition that two expressions have the same sense if and only if they can be interchangeably salva veritate whenever used in propositional attitude context. If the expressions for the analysands and the analysandum in (1) met this condition, (1) and (2) would not raise the first paradox, but the second paradox arises regardless of whether the expression for the analysand and the analysandum meet this condition. The second paradox is a matter of the failure of such expressions to be interchangeable salva veritate in sentences involving such contexts as an analysis is given thereof. Thus, a solution (such as the one offered) that is aimed only at such contexts can solve the second paradox. This is clearly false for the first paradox, however, which will apply to all pairs of propositions expressed by sentences in which expressions for pairs of analysands and analysantia raising the first paradox is interchangeable.

One approach to the first paradox is to argue that, despite the apparent epistemic inequivalence of (1) and (2), the concept of justified true belief not essentially grounded in any falsehood is still identical with the concept of knowledge (Sosa, 1983). Another approach is to argue that in the sort of analysis raising the first paradox, the analysand and analysandum is concepts that are different but that bear a special epistemic relation to each other. Elsewhere, the development is such an approach and suggestion that this analysand-analysandum relation has the following facets.

(I) The analysand and analysandum are necessarily coextensive, i.e., necessarily every instance of one is an instance of the other.

(ii) The analysand and analysandum are knowable theoretical to be coextensive.

(iii) The analysandum is simpler than the analysands a condition whose necessity is recognized in classical writings on analysis, such as, Langford, 1942.

(iv) The analysand do not have the analysandum as a constituent.

Condition (iv) rules out circularity. But since many valuable quasi-analyses are partly circular, e.g., knowledge is justified true belief supported by known reasons not essentially grounded in any falsehood, it seems best to distinguish between full analysis, from that of (iv) is a necessary condition, and partial analysis, for which it is not.

These conditions, while necessary, are clearly insufficient. The basic problem is that they apply too many pairs of concepts that do not seem closely enough related epistemologically to count as analysand and analysandum, such as the concept of being six and the concept of the fourth root of 1296. Accordingly, its solution upon what actually seems epistemologically distinctive about analyses of the sort under consideration, which is a certain way they can be justified. This is by the philosophical example-and-counterexample method, which is in a general term that goes as follows. 'J' investigates the analysis of 'K's' concept 'Q' (where 'K' can but need not be identical to 'J' by setting 'K' a series of armchair thought experiments, i.e., presenting 'K' with a series of simple described hypothetical test cases and asking 'K' questions of the form If such-and-such where the case would this count as a case of 'Q'? J then contrasts the descriptions of the cases to which; 'K' answers affirmatively with the description of the cases to which 'K' does not, and 'J' generalizes upon these descriptions to arrive at the concepts (if possible not including the analysandum) and their mode of combination that constitute the analysand of 'K's' concept 'Q'. Since 'J' need not be identical with 'K', there is no requirement that K himself be able to perform this generalization, to recognize its result as correct, or even to understand the analysand that is its result. This is reminiscent of Walton's observation that one can simply recognize a bird as a blue jay without realizing just what feature of the bird (beak, wing configurations, etc.) form the basis of this recognition. (The philosophical significance of this way of recognizing is discussed in Walton, 1972) 'K' answers the questions based solely on whether the described hypothetical cases just strike him as cases of 'Q'. 'J' observes certain strictures in formulating the cases and questions. He makes the cases as simple as possible, to minimize the possibility of confusion and to minimize the likelihood that 'K' will draw upon his philosophical theories (or quasi-philosophical, a rudimentary notion if he is unsophisticated philosophically) in answering the questions. For this conflicting result, the conflict should other things being equal be resolved in favours of the simpler case. 'J' makes the series of described cases wide-ranging and varied, with the aim of having it be a complete series, where a series is complete if and only if no case that is omitted in such that, if included, it would change the analysis arrived at. 'J' does not, of course, use as a test-case description anything complicated and general enough to express the analysand. There is no requirement that the described hypothetical test cases be formulated only in terms of what can be observed. Moreover, using described hypothetical situations as test cases enables 'J' to frame the questions in such a way as to rule out extraneous background assumption to a degree, thus, even if 'K' correctly believes that all and only 'P's' are 'R's', the question of whether the concepts of 'P', 'R', or both enter the analysand of his concept 'Q' can be investigated by asking him such questions as Suppose (even if it seems preposterous to you) that you were to find out that there was a 'P' that was not an 'R'. Would you still consider it a case of 'Q'?

Taking all this into account, the necessary conditions for this sort of analysand-analysandum relations is as follows: If 'S' is the analysand of 'Q', the proposition that necessarily all and only instances of S are instances of 'Q' can be justified by generalizing from intuition about the correct answers to questions of the sort indicated about a varied and wide-ranging series of simple described hypothetical situations. It so does occur of antinomy, when we are able to argue for, or demonstrate, both a proposition and its contradiction, roughly speaking, a contradiction of a proposition 'p' is one that can be expressed in form 'not-p', or, if 'p' can be expressed in the form 'not-q', then a contradiction is one that can be expressed in the form 'q'. Thus, e.g., if p is 2 + 1 = 4, then, 2 + 1 ≠4 is the contradictory of 'p', for 2 + 1 ≠ 4 can be expressed in the form not (2 + 1 = 4). If p is 2 + 1 ≠4, then 2 + 1 - 4 is a contradictory of 'p', since 2 + 1 ≠4 can be expressed in the form not (2 + 1 = 4). This is, mutually, but contradictory propositions can be expressed in the form, 'r', 'not-r'. The Principle of Contradiction says that mutually contradictory propositions cannot both be true and cannot both be false. Thus, by this principle, since if p is true, not-p is false, no proposition p can be at once true and false (otherwise both 'p' and its contradictories would be false?). In particular, for any predicate 'p' and object 'χ', it cannot be that 'p'; is at once true of 'χ' and false of 'χ'? This is the classical formulation of the principle of contradiction, but it is nonetheless, that we cannot now fault either demonstrates. We would eventually hope to be able to solve the antinomy by managing, through careful thinking and analysis, eventually to fault either or both demonstrations.

The conjunction of a proposition and its negation, where the law of non-contradiction provides that no such conjunction can be true: not (p & not-p). The standard proof of the inconsistency of a set of propositions or sentences is to show that a contradiction may be derived from them.

In Hégélien and Marxist writing the term is used more widely, as a contradiction may be a pair of features that together produce an unstable tension in a political or social system: a 'contradiction' of capitalism might be the aérosol of expectations in the workers that the system cannot require. For Hegel the gap between this and genuine contradiction is not as wide as it is for other thinkers, given the equation between systems of thought and their historical embodiment.

A contradictarian approach to problems of ethics asks what solution could be agreed upon by contradicting parties, starting from certain idealized positions (for example, no ignorance, no inequalities of power enabling one party to force unjust solutions upon another, no millicious ambitions). The idea of thinking of civil society, with its different distribution of rights and obligations, as if it were established by a social contract, derives from the English philosopher and mathematician Thomas Hobbes and Jean-Jacques Rousseau (1712-78). The utility of such a model was attacked by the Scottish philosopher, historian and essayist David Hume (1711-76), who asks why, given that non-historical event of establishing a contract took place. It is useful to allocate rights and duties as if it had; he also points out that the actual distribution of these things in a society owes too much to contingent circumstances to be derivable from any such model. Similar positions in general ethical theory, sometimes called contradictualism: see the right thing to do so one that could be agreed upon in hypothetical contract.

Somewhat loosely, a paradox arises when a set of apparent incontrovertible premises gives unacceptable or contradictory conclusions, to solve a paradox will involve either showing that there is a hidden flaw in the premises, or that the reasoning is erroneous, or that the apparent unacceptable conclusion can, in fact, be tolerated. Paradoxes are themselves important in philosophy, for until one is solved it shows that there is something that we do not understand. Such are the paradoxes as compelling arguments from unexceptionable premises to an unacceptable conclusion, and more strictly, a paradox is specified to be a sentence that is true if and only if it is false: For example of the latter would be: 'The displayed sentence is false.

It is easy to see that this sentence is false if true, and true if false. A paradox, in either of the senses distinguished, presents an important philosophical challenge. Epistemologist are especially concerned with various paradoxes having to do with knowledge and belief.

Moreover, paradoxes are as an easy source of antinomies, for example, Zeno gave some famously lets say, logical-non-mathematical arguments that might be interpreted as demonstrating that motion is impossible. But our eyes as it was, demonstrate motion (exhibit moving things) all the time. Where did Zeno go wrong? Where do our eyes go wrong? If we cannot readily answer at least one of these questions, then we are in antinomy. In the Critique of Pure Reason, Kant gave demonstrations of the same kind -in the Zeno example they were obviously not the same kind of both, e.g., that the world has a beginning in time and space, and that the world has no beginning in time or space. He argues that both demonstrations are at fault because they proceed on the basis of pure reason unconditioned by sense experience.

At this point, we display attributes to the theory of experience, as it is not possible to define in an illuminating way, however, we know what experiences are through acquaintances with some of our own, e.g., visual experiences of as afterimage, a feeling of physical nausea or a tactile experience of an abrasive surface (which might be caused by an actual surface -rough or smooth, or which might be part of a dream, or the product of a vivid sensory imagination). The essential feature of experience is it feels a certain way -that there is something that it is like to have it. We may refer to this feature of an experience as its character.

Another core feature of the sorts of experiences with which this may be of a concern, is that they have representational content. (Unless otherwise indicated, experience will be reserved for their contentual representations.) The most obvious cases of experiences with content are sense experiences of the kind normally involved in perception. We may describe such experiences by mentioning their sensory modalities ad their contents, e.g., a gustatory experience (modality) of chocolate ice cream (content), but do so more commonly by means of perceptual verbs combined with noun phrases specifying their contents, as in Macbeth saw a dagger. This is, however, ambiguous between the perceptual claim There was a (material) dagger in the world that Macbeth perceived visually and Macbeth had a visual experience of a dagger (the reading with which we are concerned, as it is afforded by our imagination, or perhaps, experiencing mentally hallucinogenic imagery).

As in the case of other mental states and events with content, it is important to distinguish between the properties that and experience represents and the properties that it possesses. To talk of the representational properties of an experience is to say something about its content, not to attribute those properties to the experience itself. Like every other experience, a visual; experience of a non-shaped square, of which is a mental event, and it is therefore not itself, or finds to some irregularity or is it square, even though it represents those properties. It is, perhaps, fleeting, pleasant or unusual, even though it does not represent those properties. An experience may represent a property that it possesses, and it may even do so in virtue of a rapidly changing (complex) experience representing something as changing rapidly. However, this is the exception and not the rule.

Which properties can be [directly] represented in sense experience is subject to debate. Traditionalists include only properties whose presence could not be doubted by a subject having appropriate experiences, e.g., colour and shape in the case of visual experience, and apparent shape, surface texture, hardness, etc., in the case of tactile experience. This view is natural to anyone who has an egocentric, Cartesian perspective in epistemology, and who wishes for pure data in experiences to serve as logically certain foundations for knowledge, especially to the immediate objects of perceptual awareness in or of sense-data, such categorized of colour patches and shapes, which are usually supposed distinct from surfaces of physical objectivity. Qualities of sense-data are supposed to be distinct from physical qualities because their perception is more relative to conditions, more certain, and more immediate, and because sense-data is private and cannot appear other than they are they are objects that change in our perceptual field when conditions of perception change: Physical objects remain constant.

Others who do not think that this wish can be satisfied, and who are more impressed with the role of experience in providing animisms with ecologically significant information about the world around them, claim that sense experiences represent properties, characteristic and kinds that are much richer and much more wide-ranging than the traditional sensory qualities. We do not see only colours and shapes, but they tell us, but also Earth, water, men, women and fire: We do not smell only odors, but also food and filth. There is no space here to examine the factors relevantly responsible to their choice of situational alternatives. Yet, this suggests that character and content are not really distinct, and there is a close tie between them. For one thing, the relative complexity of the character of sense experience places limitations upon its possible content, e.g., a tactile experience of something touching ones left ear is just too simple to carry the same amount of content as typically convincing to an every day, visual experience. Moreover, the content of a sense experience of a given character depends on the normal causes of appropriately similar experiences, e.g., the sort of gustatory experience that we have when eating chocolate would be not represented as chocolate unless it was normally caused by chocolate. Granting a contingent ties between the character of an experience and its possible causal origins, once, again follows that its possible content is limited by its character.

Character and content are none the less irreducibly different, for the following reasons. (1) There are experiences that completely lack content, e.g., certain bodily pleasures. (2) Not every aspect of the character of an experience with content is relevant to that content, e.g., the unpleasantness of an aural experience of chalk squeaking on a board may have no representational significance. (3) Experiences in different modalities may overlap in content without a parallel overlap in character, e.g., visual and tactile experiences of circularity feel completely different. (4) The content of an experience with a given character may vary according to the background of the subject, e.g., a certain content singing bird only after the subject has learned something about birds.

According to the act/object analysis of experience (which is a special case of the act/object analysis of consciousness), every experience involves an object of experience even if it has no material object. Two main lines of argument may be offered in support of this view, one phenomenological and the other semantic.

In an outline, or projective view, the phenomenological argument is as follows. Whenever we have an experience, even if nothing beyond the experience answers to it, we seem to be presented with something through the experience (which is itself diaphanous). The object of the experience is whatever is so presented to us-is that it is an individual thing, an event, or a state of affairs.

The semantic argument is that objects of experience are required in order to make sense of certain features of our talk about experience, including, in particular, the following. (1) Simple attributions of experience, e.g., Rod is experiencing an oddity that is not really square but in appearance it seems more than likely a square, this seems to be relational. (2) We appear to refer to objects of experience and to attribute properties to them, e.g., The after-image that John experienced was certainly odd. (3) We appear to quantify ov er objects of experience, e.g., Macbeth saw something that his wife did not see.

The act/object analysis comes to grips with several problems concerning the status of objects of experiences. Currently the most common view is that they are sense-data - private mental entities that actually posses the traditional sensory qualities represented by the experiences of which they are the objects. But the very idea of an essentially private entity is suspect. Moreover, since an experience may apparently represent something as having a determinable property, e.g., redness, without representing it as having any subordinate determinate property, e.g., any specific shade of red, a sense-datum may actually have a determinate property subordinate to it. Even more disturbing is that sense-data may have contradictory properties, since experiences can have contradictory contents. A case in point is the waterfall illusion: If you stare at a waterfall for a minute and then immediately fixate on a nearby rock, you are likely to have an experience of the rocks moving upward while it remains in the same place. The sense-data theorist must either deny that there are such experiences or admit contradictory objects.

These problems can be avoided by treating objects of experience as properties. This, however, fails to do justice to the appearances, for experience seems not to present us with properties embodied in individuals. The view that objects of experience is Meinongian objects accommodate this point. It is also attractive in as far as (1) it allows experiences to represent properties other than traditional sensory qualities, and (2) it allows for the identification of objects of experience and objects of perception in the case of experiences that constitute perception.

According to the act/object analysis of experience, every experience with content involves an object of experience to which the subject is related by an act of awareness (the event of experiencing that object). This is meant to apply not only to perceptions, which have material objects (whatever is perceived), but also to experiences like hallucinations and dream experiences, which do not. Such experiences none the less appear to represent something, and their objects are supposed to be whatever it is that they represent. Act/object theorists may differ on the nature of objects of experience, which have been treated as properties. Meinongian objects (which may not exist or have any form of being), and, more commonly private mental entities with sensory qualities. (The term sense-data is now usually applied to the latter, but has also been used as a general term for objects of sense experiences, as in the work of G.E. Moore) Act/object theorists may also differ on the relationship between objects of experience and objects of perception. In terms of perception (of which we are indirectly aware) are always distinct from objects of experience (of which we are directly aware). Meinongian, however, may treat objects of perception as existing objects of experience. But sense-datum theorists must either deny that there are such experiences or admit contradictory objects. Still, most philosophers will feel that the Meinongians acceptance of impossible objects is too high a prime rate for prices that don’t pay for such benefits.

A general problem for the act/object analysis is that the question of whether two subjects are experiencing one and the same thing (as opposed to having exactly similar experiences) appears to have an answer only on the assumption that the experiences concerned are perceptions with material objects. But in terms of the act/object analysis the question must have an answer even when this condition is not satisfied. (The answer is always negative on the sense-datum theory; it could be positive on other versions of the act/object analysis, depending on the facts of the case.)

In view of the above problems, the case for the act/object analysis should be reassessed. The Phenomenological argument is not, on reflection, convincing, for it is easy enough to grant that any experience appears to present us with an object without accepting that it actually does. The semantic argument is more impressive, but is none the less answerable. The seemingly relational structure of attributions of experience is a challenge dealt with below in connexion with the adverbial theory. Apparent reference to and quantification over objects of experience can be handled by analyzing them as reference to experiences themselves and quantification over experiences tacitly typed according to content. Thus, The after-image that John experienced was colour fully appealing becomes Johns after-image experience was an experience of colour, and Macbeth saw something that his wife did not see becomes Macbeth had a visual experience that his wife did not have.

Pure cognitivism attempts to avoid the problems facing the act/object analysis by reducing experiences to cognitive events or associated disposition, e.g., Susys experience of a rough surface beneath her hand might be identified with the event of her acquiring the belief that there is a rough surface beneath her hand, or, if she does not acquire this belief, with a disposition to acquire it that has somehow been blocked.

This position has attractions. It does full justice to the cognitive contents of experience, and to the important role of experience as a source of belief acquisition. It would also help clear the way for a naturalistic theory of mind, since there seems to be some prospect of a physicalist/functionalist account of belief and other intentional states. But pure cognitivism is completely undermined by its failure to accommodate the fact that experiences have a felt character that cannot be reduced to their content, as aforementioned.

The adverbial theory is an attempt to undermine the act/object analysis by suggesting a semantic account of attributions of experience that does not require objects of experience. Unfortunately, the oddities of explicit adverbializations of such statements have driven off potential supporters of the theory. Furthermore, the theory remains largely undeveloped, and attempted refutations have traded on this. It may, however, be founded on sound basis intuitions, and there is reason to believe that an effective development of the theory (which is merely hinting at) is possible.

The relevant intuitions are (1) that when we say that someone is experiencing an A, or has an experience of an A, we are using this content-expression to specify the type of thing that the experience is especially apt to fit, (2) that doing this is a matter of saying something about the experience itself (and maybe about the normal causes of like experiences), and (3) that it is no-good of reasons to posit of its position to presuppose that of any involvements, is that its descriptions of an object in which the experience is. Thus the effective role of the content-expression in a statement of experience is to modify the verb it compliments, not to introduce a special type of object.

Perhaps, the most important criticism of the adverbial theory is the many property problem, according to which the theory does not have the resources to distinguish between, e.g.,

(1) Frank has an experience of a brown triangle

and:

(2) Frank has an experience of brown and an experience of a triangle.

Which is entailed by (1) but does not entail it. The act/object analysis can easily accommodate the difference between (1) and (2) by claiming that the truth of (1) requires a single object of experience that is both brown and triangular, while that of the (2) allows for the possibility of two objects of experience, one brown and the other triangular, however, (1) is equivalent to:

(1*) Frank has an experience of something being both brown and triangular.

And (2) is equivalent to:

(2*) Frank has an experience of something being brown and an experience of something being triangular,

and the difference between these can be explained quite simply in terms of logical scope without invoking objects of experience. The Adverbialists may use this to answer the many-property problem by arguing that the phrase a brown triangle in (1) does the same work as the clause something being both brown and triangular in (1*). This is perfectly compatible with the view that it also has the adverbial function of modifying the verb has an experience of, for it specifies the experience more narrowly just by giving a necessary condition for the satisfaction of the experience (the condition being that there are something both brown and triangular before Frank).

A final position that should be mentioned is the state theory, according to which a sense experience of an A is an occurrent, non-relational state of the kind that the subject would be in when perceiving an A. Suitably qualified, this claim is no doubt true, but its significance is subject to debate. Here it is enough to remark that the claim is compatible with both pure cognitivism and the adverbial theory, and that state theorists are probably best advised to adopt adverbials as a means of developing their intuitions.

Yet, clarifying sense-data, if taken literally, is that which is given by the senses. But in response to the question of what exactly is so given, sense-data theories posit private showings in the consciousness of the subject. In the case of vision this would be a kind of inner picture shown which it only indirectly represents aspects of the external world that has in and of itself a worldly representation. The view has been widely rejected as implying that we really only see extremely thin coloured pictures interposed between our minds eye and reality. Modern approaches to perception tend to reject any conception of the eye as a camera or lense, simply responsible for producing private images, and stress the active life of the subject in and of the world, as the determinant of experience.

Nevertheless, the argument from illusion is of itself the usually intended directive to establish that certain familiar facts about illusion disprove the theory of perception called naïevity or direct realism. There are, however, many different versions of the argument that must be distinguished carefully. Some of these distinctions center on the content of the premises (the nature of the appeal to illusion); others center on the interpretation of the conclusion (the kind of direct realism under attack). Let us set about by distinguishing the importantly different versions of direct realism which one might take to be vulnerable to familiar facts about the possibility of perceptual illusion.

A crude statement of direct realism might go as follows. In perception, we sometimes directly perceive physical objects and their properties, we do not always perceive physical objects by perceiving something else, e.g., a sense-datum. There are, however, difficulties with this formulation of the view, as for one thing a great many philosophers who are not direct realists would admit that it is a mistake to describe people as actually perceiving something other than a physical object. In particular, such philosophers might admit, we should never say that we perceive sense-data. To talk that way would be to suppose that we should model our understanding of our relationship to sense-data on our understanding of the ordinary use of perceptual verbs as they describe our relation to and of the physical world, and that is the last thing paradigm sense-datum theorists should want. At least, many of the philosophers who objected to direct realism would prefer to express in what they were of objecting too in terms of a technical (and philosophically controversial) concept such as acquaintance. Using such a notion, we could define direct realism this way: In veridical experience we are directly acquainted with parts, e.g., surfaces, or constituents of physical objects. A less cautious venison of the view might drop the reference to veridical experience and claim simply that in all experience we are directly acquainted with parts or constituents of physical objects. The expressions knowledge by acquaintance and knowledge by description, and the distinction they mark between knowing things and knowing about things, are generally associated with Bertrand Russell (1872-1970), that scientific philosophy required analyzing many objects of belief as logical constructions or logical fictions, and the programme of analysis that this inaugurated dominated the subsequent philosophy of logical atomism, and then of other philosophers, Russells The Analysis of Mind, the mind itself is treated in a fashion reminiscent of Hume, as no more than the collection of neutral perceptions or sense-data that make up the flux of conscious experience, and that looked at another way that also was to make up the external world (neutral monism), but An Inquiry into Meaning and Truth (1940) represents a more empirical approach to the problem. Yet, philosophers have perennially investigated this and related distinctions using varying terminology.

Distinction in our ways of knowing things, highlighted by Russell and forming a central element in his philosophy after the discovery of the theory of definite descriptions. A thing is known by acquaintance when there is direct experience of it. It is known by description if it can only be described as a thing with such-and-such properties. In everyday parlance, I might know my spouse and children by acquaintance, but know someone as the first person born at sea only by description. However, for a variety of reasons Russell shrinks the area of things that can be known by acquaintance until eventually only current experience, perhaps my own self, and certain universals or meanings qualify anything else is known only as the thing that has such-and-such qualities.

Because one can interpret the relation of acquaintance or awareness as one that is not epistemic, i.e., not a kind of propositional knowledge, it is important to distinguish the above aforementioned views read as ontological theses from a view one might call epistemological direct realism? In perception we are, on at least some occasions, non-inferentially justified in believing a proposition asserting the existence of a physical object. Since it is that these objects exist independently of any mind that might perceive them, and so it thereby rules out all forms of idealism and phenomenalism, which hold that there are no such independently existing objects. Its being to direct realism rules out those views defended under the cubic of critical naive realism, or representational realism, in which there is some non-physical intermediary -usually called a sense-datum or a sense impression -that must first be perceived or experienced in order to perceive the object that exists independently of this perception. Often the distinction between direct realism and other theories of perception is explained more fully in terms of what is immediately perceived, than mediately perceived. What relevance does illusion have for these two forms of direct realism?

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