Cartesianism
n. the system of philosophy developed by René Descartes. The three fundamental tenets of the system are (a) that all knowledge forms a unity; (b) that the purpose of knowledge is to provide humankind with the means of mastery over the natural world; and (c) that all knowledge must be built up from a foundation of indubitable first principles, the truth of which can be known intuitively (see innate ideas). Many ideas and assumptions influential in psychology can be traced back to Descartes, including the notion of a rational self capable of knowing truth, the contention that the most trustworthy knowledge is of the contents of one’s own mind, and the idea that the deductive methods that have been successful in producing certainty in mathematics can be applied to produce equally valid knowledge in other fields of human endeavor. Of particular importance to the development of psychology are Descartes’ understanding of
the ego (see Cartesian self) and his attempt to explain the relation of the mind to the body (see Cartesian dualism). See also modernism; rationalism. —Cartesian
adj.