Kantian constructivism and the Reinhold-Sidgwick objection

In this paper, I give a reconstruction of the so-called Reinhold-Sidgwick objection and show that Korsgaard-style Kantian constructivists are committed to two key premises of the underlying argument. According to the Reinhold-Sidgwick objection, the Kantian conception of autonomy entails the absurd conclusion that no one is ever morally responsible for a morally wrong action. My reconstruction of the underlying argument reveals that the objection depends on a third premise, which says that freedom is a necessary condition for moral responsibility. After mapping the common replies to the objection, I demonstrate that none of these replies is available to Kantian constructivists. But they need not be committed to the absurd conclusion that no one is ever morally blameworthy. Kantian constructivists who want to resist the Reinhold-Sidgwick objection are well advised to subject the third premise of the underlying argument to critical scrutiny.