Descartes was a French mathematician and soldier who spent most of his productive life in the Dutch Republic. In 1619, shut in a stove-heated room in Germany, he had three dreams that convinced him he had found the foundation of a new philosophy. He resolved to doubt everything that could be doubted. What survived was the thinking self: cogito ergo sum. From this single certainty he attempted to rebuild all of knowledge. He split the world into mind and body, a division that haunted philosophy for centuries. He died in Stockholm in 1650, tutoring Queen Christina of Sweden in philosophy at five in the morning.
Born in a small town in the Loire Valley. His mother died when he was an infant. He was a sickly child, and his teachers at the Jesuit college of La Fleche allowed him to stay in bed late each morning, a habit he kept for life.
