Rene Descartes was a French philosopher, mathematician, and scientist who lived from 1596 to 1650. He is widely considered the father of modern Western philosophy and made significant contributions to mathematics, including the development of analytic geometry and the Cartesian coordinate system. Descartes is best known for his philosophical statement "Cogito, ergo sum" ("I think, therefore I am"), which forms the foundation of his rationalist approach to knowledge and existence.