  One way of characterizing Du Châtelet's Foundations is to show that it is a reaction against Cartesian natural philosophy and in favor of Newtonian physics. In the main, this is correct. Indeed, by the time Du Châtelet turned her attention to the project of the Foundations, the popularity of Cartesian natural philosophy was on the wane in France, the popularity of Newtonain physics was on the rise, and Du Châtelet was in the thick of these movements. Still, two facts should give us pause when making the general claim just articulated. The first is that Cartesian natural philosophy and Newtonian physics have different scopes, with the former presenting a unified system of metaphysics grounding and constraining the physics that follows from the metaphysics. Indeed, Du Châtelet's commitment to developing a natural philosophy (rather than writing simply about physics) required that she find an appropriate metaphysics to ground Newtonain physics, thus presenting a unified system to replace the (in her and others' view) defunct system of Descartes.