 Among those who think that Aquinas’s God leaves room for indeterministic human agency, there remains a fundamental difference of opinion. Some (e.g., Stump 2003 ch. 9) think that such freedom, for Aquinas, requires only that the will be an ultimate source, a first creaturely cause. Others think that, in addition to this, Aquinas further requires the leeway to choose among alternative possibilities (e.g., Hoffmann and Michon 2017). Either way, a libertarian reading of Aquinas is likely to stress his claim that the will is a self-mover: “Just as the will moves other capacities, so it also moves itself” (Quest. on Evil 6c; Gallagher 1994). This is an idea, moreover, that Aquinas had urged from his very first discussion of free choice in his Sentences commentary, where he argued that free choice is possessed only by beings who “determine for themselves their end and their action toward that end” (Sentences II.25.1c). In some sense, then, the will is free because it is self-determining. This distinguishes it from natural, non-voluntary agents, whose determination comes from without. Aquinas’s focus on the will’s role in such self-determination—a tendency that becomes more prominent in his later works—makes it reasonable to include him in the thirteenth-century movement away from ancient intellectualism and toward a voluntaristic conception of human nature. In emphasizing the will’s overarching control, Aquinas can appeal to the critical importance of the will’s various operations and dispositions. The act of love, foundational to any Christian ethics, is an operation of will. The dispositions of justice and charity—the central virtues of philosophy and theology, respectively—are both virtues of the will. But it is not clear that Aquinas goes so far—as  Peter John Olivi,  Henry of Ghent, and Scotus, among many others, soon would—as to exempt the will from the determinism that was agreed to characterize the rest of the natural world. There remains a lively debate among scholars over this issue.