Descartes against the materialists: How Descartes’ confrontation with materialism shaped his metaphysics

It is a historical prejudice that Cartesian dualism was a kind of default position for the seventeenth century, the position that every reader was likely to hold. In actuality, materialism was quite widespread. This is reflected in the Meditations and the Objections and Replies to the Meditations, where materialism is a frequent issue, a constant undercurrent to the discussion. In this chapter I would like to explore some aspects of Descartes’ reactions to materialism. My thesis is that it was at least in part his response to materialism that forced Descartes to make an important move in his thought. I will claim that certain crucial aspects of his doctrine of substance may have come directly out of his confrontation with materialism in the Objections and Replies to the Meditations. I will proceed as follows. I begin not with Descartes, but with the objections that Hobbes made to the doctrine of the real distinction between mind and body in the Third Objections. These objections, I shall argue, turn on a certain feature of the doctrine of substance that Descartes presented in the Meditations and in the Appendix to the Second Replies. I shall then show how Descartes’ response to those objections resulted in an important shift in his doctrine of substance, one that had profound consequences for his conception of metaphysics.