Born in Paris, Cordemoy served as a lawyer in the Parlement of Paris, but he was also active in the philosophical conferences of the French capital, including those of Emmanuel Maignan (1601–76) and Jacques Rohault (1618–72). His major works are Le discernement du corps et de l’âme en six discours pour servir à l'eclaircissement de la physique (1666) and Discours physique de la parole (1668). In 1673 he was appointed tutor to the dauphin, and in 1683 he became director of the Académie française, having been elected a member eight years earlier. He died October 15, 1684. Cordemoy's importance to Cartesianism in particular and to seventeenth-century thought in general results chiefly from three factors. First, he is the only Cartesian atomist. Cordemoy arrives at atomism from what he takes to be the logical consequence of a Cartesian understanding of substance (see AT VIIIA 24–25, CSM I 210). Substances, he claims, are essentially metaphysically simple, and for extended substance, this implies atomism. So for him, it is not merely a contingent physical fact that the corporeal world is at root composed of atoms, or bodies (les corps, assemblages of which constitute matter); it is a metaphysical requirement, given a clear and distinct understanding of the concept of substance. Second, Cordemoy is one of the first, if not the first, of Cartesian philosophers to argue that Descartes’ metaphysics demands an occasionalist understanding of causation. Beginning with “interaction” between bodies, and then extending his analysis to body-mind and mind-body “interaction,” Cordemoy argues that only God could be the cause of the effects generated in such instances. He begins his argument by taking as axiomatic that nothing can lose something essential to it without ceasing to be what it is. As bodies can lose their motion, motion cannot be for them an essential property. Further, as motion is a mode of bodies, and because Cartesian metaphysics does not permit a particular token mode to be transferred to another substance, bodies cannot give each other motion. Only something that itself is not a body could be the cause of motion in bodies. Cartesian ontology contains only minds and bodies, and so the cause in question must be a mind. Reflection shows that our own finite minds are not the cause of motion in bodies.