Descartes, René, 1596-1650, French philosopher, mathematician, and scientist. His philosophy is called Cartesianism (from Cartesius, the Latin form of his name). Often called the father of modern philosophy, he is regarded as the bridge between scholasticism and all philosophy that followed him. Primarily interested in mathematics, he founded ANALYTIC GEOMETRY and originated the CARTESIAN COORDINATES and Cartesian curves. To algebra he contributed the treatment of negative roots and the convention of exponent notation. Descartes also contributed to optics, physiology, and psychology. His Discourse on Method (1637) and Meditations (1641) contain his important philosophical theories. Intending to extend mathematical method to all areas of human knowledge, Descartes discarded the authoritarian systems of the scholastic philosophers and began with universal doubt. Only one thing cannot be doubted: doubt itself. Therefore, the doubter must exist. This is the kernel of his famous assertion Cogito, ergo sum [I think, therefore I am]. From this certainty Descartes expanded knowledge, step by step, to admit the existence of God (as the first cause) and the reality of the physical world, which he held to be mechanistic and entirely divorced from the mind; the only connection between the two is the intervention of God. This is almost complete DUALISM.

From the Concise Columbia Encyclopedia. Copyright © 1991 by Columbia University Press.