 Clarke’s primary defense of libertarian freedom involves clarifying the relationship between the will and the judgment. In order to will, one must have a judgment about what to do and the power to choose in accordance with that judgment. This power to choose is provided by the will. The will is not to be identified with the last judgment of the understanding nor is it a volition caused by a judgment. Those (like Hobbes) who thought so were guilty of basic philosophical errors. If they maintained that the content of the evaluative proposition is either identical with the volition or causes it, then they were confusing the “moral motive” with the “physical efficient,” the physical efficient being the element of the cause that provides the active power (D 73, W 2.565). Because the moral motive is simply an abstract object (a proposition) and abstract objects are causally inert, the moral motive cannot cause anything. On the other hand, if Clarke’s opponents maintained that, not the evaluative proposition, but one’s perceiving, judging or otherwise believing it is the cause (or a partial cause) of volition, then they were falling foul of a basic causal principle. Against Descartes, Clarke insisted that judging, i.e., assenting to what appears true and dissenting from what appears false, is not an action but a passion. But what is passive cannot cause anything active. So, there is no causal link between evaluation and volition, or, as Clarke put it, between “approbation and action” (D 126, W 4.714). In general, there is no causal link between previous non-volitional mental states, all of which are passive, and any volition (Vailati 1997, 82–84).