Descartes Descartes Fr.: Descartes René Descartes (1596-1650), French mathematician, physicist, and philosopher, who made valuable contributions to mathematics, physics, and philosophy. Descartes was a pioneer and major figure in 17th century rationalism. He represents a major break with the Aristotelianism and Scholasticism of the Medieval period. René Descartes is regarded as the father of modern philosophy. → Descartes ray, → Cartesian coordinates, → Cartesian vortex theory. |