. Also called theory of knowledge, occasionally gnoseology. Enquiry into the nature and grounds of knowledge. ‘What can we know, and how do we know it?’ are questions central to philosophy, and knowledge forms the main topic of epistemology, along with its relation to other cognitive notions like BELIEF, understanding, REASON, JUDGEMENT, SENSATION, PERCEPTION, INTUITION, guessing, learning, forgetting. See philosophy of MIND (last paragraph) for philosophy of mind and epistemology.
Questions about knowledge can be divided into four main, though overlapping, groups, concerning its nature, its types, what is known, and its origin. Knowledge clearly differs in its nature from purely psychological states like feeling sure, for in straightforward contexts the word ‘know’, like ‘realize’, ‘REFUTE’, and many other words, can only be used by a speaker who himself has certain beliefs on the matter in question. If I say ‘Smith knows (or, Smith does not know) that fairies exist’ I commit myself to their existence, which I do not if I say ‘Smith believes (feels sure, is sure)…’ Verbs like ‘know’ are sometimes called factive to express this feature. Knowing is usually thought to involve believing, though some say that it replaces belief, or that one can believe one thing while somehow knowing the opposite.
It is often thought that knowledge is justified true belief, but even if belief is involved there are objections to this view. No agreed account has yet been produced of what counts as justification, and sometimes no justification seems called for; do we have to justify claims to know our own intentions, or where our limbs are? Some say we have a special knowledge without observation of certain things, e.g. (in normal health) where our limbs are, which others can only know by observing us.
Justification may be internalist or externalist (see INTERNALISM AND EXTERNALISM). Internalist justification focuses on the knowers’ state of mind and demands that he be aware of (have at least a true belief in), and preferably be able to produce some adequate reason for the truth of, the relevant belief, though what counts as adequate can be disputed: obviously if one is in error one has not knowledge, but must error be not only absent but impossible (cf. INCORRIGIBLE)? If so, knowledge will be rare. Externalist justification stresses the difference between knower and known and demands some real connection between them. This may take the form of a suitable causal link whereby what is known causes the knower’s belief, or is perhaps jointly with the belief caused by some third thing; this would allow for knowledge of the future etc. The knower may be allowed to make inferences, but purely intellectual knowledge, e.g. of logic or mathematics, may be hard to cater for, since causation does not seem to apply there. Another difficulty is that causation was introduced to prevent the belief being merely accidentally true, but the causal chain itself may be of a deviant kind; e.g. suppose a volcano causes some lava to cover a field, which causes a farmer to remove it, which causes a conservationist fanatic to replace it, which causes a newcomer to perceive it and infer the volcano’s existence: does the newcomer know the volcano existed?
Another externalist approach is reliabilism (sometimes used to include causal theories). This may be a criterion for knowledge, or simply for justification (whereby a belief is justified if it is produced by a method that normally produces true beliefs, even if it happens to be false this time; for knowledge of course it must be true). Reliabilism may, however, be partly internalist if it is insisted that the believer be aware of the method used and of its reliability. (Similarly a causal theory may become partly internalist if the knower must be aware of the relevant causal chain.) If a belief so produced is true it can be called knowledge, but an objection is that even a normally reliable method may sometimes produce a belief which is true but only by chance or for reasons unconnected with the method: would that still count as knowledge? Also has one knowledge if one is regularly right but can give no reasons, though the subject-matter seems to demand them (e.g. successful soothsaying)?
Internalists and externalists agree that knowledge must in a certain sense be not accidental. Suppose that by chance I witness a traffic accident. The event was accidental (it could even be uncaused for all that concerns us here) and my knowing of it is accidental (I only saw it by chance); but it is not accidental that my belief that there was an accident is true.
Other accounts of knowledge introduce causation, or make ‘know’ a performative verb (see SPEECH ACTS) or say that to know is to be able to tell.
Does knowing involve knowing that one knows? How far do knowledge and the other cognitive notions involve consciousness and rationality: can humans have unconscious knowledge? Can animals and machines have knowledge at all?
The types of knowledge often occur in pairs. A PRIORI and empirical knowledge have long been contrasted (see also below on origins), and the ANALYTIC/synthetic distinction is relevant here. If a priori knowledge is analytic it risks having no content, since analytic propositions seem merely to repeat (part of) the subject in the predicate, inplicitly or implicitly, or to do something analogous to that. Kant postulated synthetic a priori propositions, known by TRANSCENDENTAL ARGUMENTS, but their existence is controversial.
Knowing propositions or facts (propositional knowledge, e.g. knowing that Paris is the capital of France) is contrasted with knowing objects (i.e. knowing Paris). ‘OBJECTS’ must presumably be wide enough to include things like someone’s character, and knowing objects may anyway involve knowing facts about them.
Russell distinguished knowledge by acquaintance from knowledge by description, a distinction only intelligible in the light of his theory of DESCRIPTIONS. If I am acquainted with an object it can be a constituent of a proposition I understand, and its logically proper name will be the subject of that proposition. If I know such a proposition to be true I have knowledge by acquaintance of the object. If on the other hand I know the proposition that the last French king was beheaded, whose subject is a description, I have knowledge by description of that king, whether or not I am also acquainted with him. By acquaintance Russell apparently means a form of immediate knowledge which is not propositional but consists in confrontation. ‘Immediate knowledge’ might cover some propositional knowledge like knowledge without observation, some perceptual knowledge, telepathy and intuition, but there are difficulties over just what acquaintance, in Russell’s sense, consists in.
Ryle contrasts knowing how and knowing that, and this distinction has been widely used in, for example, ethics and philosophy of mind, e.g. moral knowledge might consist in knowing how to behave.
Some types of knowledge are partly defined in terms of what is known, including memory, of the past, and precognition, of the future.
The objects we have knowledge of are legion, and apart from the general problems of SCEPTICISM some of these objects raise special problems about how, rather than whether, we know them. One such sphere is knowledge about ourselves, especially about our existence, our feelings and their locations (when they have them; see SENSATIONS), our mental states and characteristics, and the position of our limbs (see above). A controversial notion relevant here is private or privileged ACCESS. Some philosophers, notably Wittgenstein, claim that we cannot have knowledge unless the idea of our being mistaken makes sense, e.g. we cannot know, nor not know, that we are in pain. Other such spheres include the past (including dreams), the future, general facts and scientific laws, logical and mathematical facts, philosophical, religious, moral and aesthetic facts. In many of these cases it is disputed whether, strictly, there are any such facts to be known.
RATIONALISTS and EMPIRICISTS have traditionally battled over the origin of knowledge. Can the mind to any degree actively originate its contents, or are those contents entirely built up from what it passively receives through the senses or introspection, as the tabula rasa or blank tablet theory suggests? The strong empiricist and sceptical trend in English-language philosophy earlier in this century has now largely broken down as the issue has become less clearcut. Here too belong questions about conceptual schemes, or basic ways of looking at the world. How fundamental can differences between them be? e.g. must we view the world in terms of substances and attributes, etc., or could we substitute an alternative scheme? Cf. CATEGORIES.
Epistemology includes further questions somehow related to knowledge. Rigour and provability concern the acquisition of knowledge. TRUTH and PROBABILITY concern the assessment of it. MEANING and other notions relating to language concern the vehicle of it. METAPHYSICS, LOGIC, and philosophies of MATHEMATICS, SCIENCE and LANGUAGE are all relevant here.
Genetic epistemology, associated largely with J.Piaget (1896–1980) and his followers, studies empirically the acquisition of concepts and mental abilities by children, and belongs to psychology rather than philosophy. For moral epistemology see ETHICS.
Naturalized epistemology, a notion mainly associated nowadays with Quine though having its roots in Hume, is what results when instead of trying to justify in the traditional manner our claims to knowledge we offer a causal account, particularly in terms of evolution, of how we come, and inevitably come, to have the kinds of belief we have (cf. NATURALISM).
J.L.Austin, ‘Other minds’, in his Philosophical Papers, 1961. (‘Know’ as performative verb.)
A.J.Ayer, Problem of Knowledge, Macmillan, 1956, Penguin, 1990. (Empiricist approach.)
E.Craig, Knowledge and the State of Nature, Clarendon, 1990. (Aims not to define knowledge but to account for it in terms of why we have the concept.)
*J.Dancy, Introduction to Contemporary Epistemology, Blackwell, 1985.
J.Dancy (ed.), Perceptual Knowledge, Oxford UP, 1988. (Reprinted essays on knowledge as connected with perception.)
D.Davidson, ‘On the very idea of a conceptual scheme’ in his Inquiries into Truth and Interpretation, Clarendon, 1984. (Attacks idea that knowledge is relative to conceptual schemes.)
A.I.Goldman, ‘A causal theory of knowing’, Journal of Philosophy, 1967. (Cf. also B.Skyrms, ‘The explication of “X knows that p”’, ibid. Goldman is reprinted with discussions in Pappas and Swain. For his later views see his Epistemology and Cognition, Harvard UP, 1986, which also discusses reliabilist criterion for knowledge (chapter 3) and for justification (chapter 5).)
A.P.Griffiths (ed.), Knowledge and Belief, Oxford UP, 1967. (Articles and bibliography, with introduction. Note E.Gettier’s objections to the ‘justified true belief’ definition of ‘knowledge’.)
D.W.Hamlyn, Theory of Knowledge, Macmillan, 1970. (More advanced introduction.)
N.Malcolm, ‘The privacy of experience’, in A.Stroll (ed.), Epistemology, Harper and Row, 1967. (Wittgensteinian view of knowledge and error. Compare (and contrast) his article in Griffiths, above.)
Midwest Studies in Philosophy, vol. 5, 1980. (Single topic journal issue entitled Studies in Epistemology.)
G.S.Pappas and M.Swain (eds), Essays on Knowledge and Justification, Cornell UP, 1978. (General readings.)
B.Russell, ‘Knowledge by acquaintance and knowledge by description’, in his Mysticism and Logic, Penguin, 1918. (Cf. INTUITION.)
G.Ryle, The Concept of Mind, Hutchinson, 1949, chapter 2. (Knowing how and that. For criticism see D.G.Brown, ‘Knowing how and knowing that, what’, in G.Pitcher and O.Wood (eds), Ryle, Macmillan, 1970, and for use in ethics J.Gould, The Development of Plato’s Ethics, 1955.)
G.Ryle, ‘Epistemology’, in J.O.Urmson (ed.), The Concise Encyclopaedia of Western Philosophy and Philosophers, 1960. (Brings out breakdown of rationalist/empiricist contrast.)
W.V.O.Quine, ‘Epistemology naturalized’, in his Ontological Relativity and Other Essays, Columbia UP, 1969. (Cf. also M.J.Woods, ‘Scepticism and natural knowledge’, Proceedings of the Aristotelian Society, 1979–80, D.Papineau, ‘Is epistemology dead?’, Proceedings of the Aristotelian Society, 1981–2.)
C.Sartwell, ‘Knowledge is merely true belief’, American Philosophical Quarterly, 1991, ‘Why knowledge is merely true belief’, Journal of Philosophy, 1992. (Defends this claim, first article answering objections and second giving positive account.)
G.N.A.Vesey, The Embodied Mind, Allen and Unwin, 1965, Chapter 7, § 5. (Discussion of knowledge without observation.)
D.Wilson, Presuppositions and Non-Truth-Conditional Semantics, Academic Press, 1971, Gregg Revivals, 1991. (See index for factives.)
*A.D.Woozley, Theory of Knowledge, Hutchinson, 1949. (Elementary introduction.)
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