This Element discusses the roles played by the idea of God in René Descartes' epistemology, physics, and metaphysics, and problems arising from those roles. Section 1 gives an overview of Descartes' life, works, and reception, focusing on the extent to which he is a religious or a secular thinker. Section 2 focuses on the problem of the Cartesian circle generated by his claim that all human knowledge depends on knowledge of God. Section 3 explains the role of God in Descartes' physics and addresses problems concerning how God's causal activity relates to that of creatures, including how divine providence fits with human freedom and how voluntary bodily actions are consistent with the laws of nature. Section 4 explores Descartes' claim that God freely created the eternal truths, noting its implications for his theory of modality.
