Abstract
I show that unlike her rationalist predecessor Leibniz, Du Châtelet is committed to epistemic causal idealism about natural causes. According to this view, it is constitutive of natural causes that they are in principle knowable by us (i.e., finite intelligent beings). Du Châtelet’s causal idealism stems at least in part from the distinctive theoretical role played by the Principle of Sufficient Reason in her system (as presented in her _Institutions de physique_), as well as her argument for the Principle of Sufficient Reason. I show that far from merely explicating Leibniz’s metaphysics, Du Châtelet develops a radical and novel rationalism that is in keeping with her core commitment to science.