Epistemology. A very important department of philosophical inquiry, sometimes called "theory of knowledge." The term comes from the Greek word epistēmē, knowledge (especially what would be called in modern times scientific knowledge). It is concerned with questions about the possibility of knowledge and the nature and basis of such knowledge as we claim to possess, as well as of belief and experience.

If we can know anything, how do we know it and what is the difference between knowledge and belief? The way in which and the extent to which knowledge differs from belief is controversial, but by any reckoning an important difference ties between them. Can I know without knowing that I know, or does knowledge involve knowledge of my knowing? Can my dog be said to know, and if so in what sense is his knowledge different from mine? Can a computer be said to know except in a derivative sense such as that which I might employ in saying that my skin itches because it "knows" that bacteria are attacking it? When I say that I know New York, I may mean one of several things, e.g., (1) although I have never been there I know where it is on the map and can distinguish it from Boston and Philadelphia, or (2) 1 have lived there all my life and know at least as much about it as the average New Yorker does, or (3) 1 have made a lifelong study of New York and am a leading expert on its history, the form of its government, its customs, its social problems, and much else, or again (4) 1 know only that it is a large city as are Tokyo and Calcutta. An important distinction in contemporary philosophy, emphasized by Gilbert Ryle, is that between knowing how and knowing that, e.g., I may know that Long Island is within fairly easy reach of Manhattan but I may have no idea how to get there. I may know that French table manners are different from English ones but not know how to behave well at table in either country.

Historically, the origin of knowledge has been the subject of a long-standing debate between rationalists and empiricists. Rationalists (e.g., Descartes, Spinoza, Leibniz) insist that the mind in one way or another originates its basic furnishings (e.g., "innate ideas" such as space and time), while empiricists (e.g., Berkeley and Hume) contend that the mind is, in Locke's phrase, a tabula rasa (a blank page) on which is gradually impressed, through the senses, such knowledge as we may have. Rationalism and empiricism may be conjoined, however, and the rigidity of the distinction between them breaks down, e.g., both Aristotle and Locke, each in his own way, would subscribe to both rationalist and empiricist theses. Both, for instance, would subscribe to the general principle that there is nothing in the intellect that is not first in the senses, but they would apply it in different ways. Many philosophers would question the value of talking, as does Kant of categories of knowledge. A. D. Woozley, Theory of Knowledge ( 1949) provides an elementary introduction to the subject and D. W. Hamlyn, Theory of Knowledge ( 1970) a more advanced one. A. Phillips Griffiths (ed.), Knowledge and Belief ( 1967) contains both a variety of views in the field and a bibliography.

Geddes MacGregor, Dictionary of Religion and Philosophy, New York: Paragon House, 1989