Self-Legislation and the Apriority of the Moral Law

Marcus Willaschek and I have argued against the widespread assumption that Kant claims the Moral Law—the supreme principle of morality—is (or must be regarded as) ‘self-legislated’. We argue that Kant instead describes the Moral Law as an a priori principle of the will. We also argue that his conception of autonomy concerns not the Moral Law but substantive moral laws such as the law that requires promoting the happiness of others. In the present essay, I respond to the commentary by Alyssa Bernstein and Christoph Hanisch. In response to Bernstein, I clarify the relation between our interpretation of Kant and those proposed by John Rawls and Allen Wood. In response to Hanisch, I argue, among other things, that Kant’s defense of the thesis that the Moral Law is an a priori principle of pure practical reason does not mean that practical reasoning and reasons-based action are impossible without it. It means rather that morally good and morally evil reasons-based action are impossible without it.