René Descartes
René Descartes (1596–1650) was a French scientist, philosopher and Roman Catholic who is often considered to be the founder of modern philosophy, breaking away from the ways of the middle ages.
Descartes breaks away from the philosophy of scholasticism with a concept of universal doubt. He put much faith in the scientific method as a source of knowledge.
Descartes was famous for the idea of "Cogito, ergo sum" ("I think, therefore I am")—meaning that any thinking being rather promptly asserts and proves its own existence. Descartes also sought to prove the existence of God through the idea of God in the mind of a thinking being. He also accepted the ontological proof of God that had been previously described by St. Anselm. Following this assertion, he confirms the reality of the physical world as we know it through the conclusion that a God would not try to fool the thinkers with illusions.
For Descartes, the physical world and the human mind are completely distinct entities, connected only through God.
René Descartes also made several advances in science and mathematics, particularly in geometry and algebra.