Empiricism is the theory that experience rather than reason is the source of knowledge, and in this sense it is opposed to rationalism. This general thesis, however, can receive different emphases and refinements; hence, those philosophers who have been labeled empiricists are united only in their general tendency and may differ in various ways. The word empiricism is derived from the Greek εμπειρ•α (empeiria), the Latin translation of which is experientia, from which in turn we derive the word experience. Aristotle conceived of experience as the as yet unorganized product of sense perception and memory; this is a common philosophical conception of the notion. Memory is required so that what is perceived may be retained in the mind. To say that we have learned something from experience is to say that we have come to know of it by the use of our senses. We have experience when we...