“Kant’s Demonstration of Free Will, or How to Do Things with Concepts” has been accepted for publication by the Journal of the American Philosophical Association. Typset version to follow.
Kant famously insists that free will is a condition of morality. The difficulty of providing a demonstration of freedom has left him vulnerable to devastating criticism: critics charge that Kant’s post-Groundwork justification of morality amounts to a dogmatic assertion of morality’s authority. My paper rebuts this objection, showing that Kant offers a cogent demonstration of freedom. My central claim is that the demonstration must be understood in practical rather than theoretical terms. A practical demonstration of x works by bringing x into existence, and what the demonstration of freedom brings into existence is a moral will, a will regulated by the moral law and capable of acting in accordance with it. Since to act morally is to act freely, bringing a moral will into existence actualizes our capacity for freedom and demonstrates that we possess it. To confirm the viability of such a demonstration, Kant must establish that agents can regulate their wills by practical principles, and that practical judgments are efficacious of themselves (i.e., that non-Humean motivational internalism is true). Kant, I argue, is successful on both counts.