Introduction

It is known that Descartes modified the object of metaphysics, by defining it, no longer as the science of being qua being, or as the science of the first of all beings, but as the science of the first known beings—namely, the soul and God. It is also known that Descartes modified the object of natural philosophy, by arguing that physical phenomena had to be explainable in terms of corpuscles, which were wholly determined by the properties of a matter whose essence was extension. The decoupling of physics and metaphysics grew more pronounced in the following centuries. When, around 1740, Newtonianism sounded the death knell of Cartesian science, one of the ways to preserve part of Descartes' work was to separate it from more metaphysical writings. According to the "Discours preliminaire" of the Encyclopedie, what remains of Cartesian philosophy is geometry, not metaphysics or physics—both of which were considered to be out of date.