René Descartes (1596–1650) laid out the agenda for modern philosophy in several important ways. For one, he claimed to have left behind the “shaky foundations” of knowledge from the time of the medieval schoolmen. He established a quest for certain knowledge about all matters — including nature, God, and the soul — and a deductive geometric method to attain it. In his greatest work, the Meditations, he plays out that quest for certainty in the sciences, metaphysics, and epistemology.