Korsgaard's Arguments for the Value of Humanity

In The Sources of Normativity and elsewhere, Korsgaard defends a Kantian ethical theory by arguing that valuing anything commits one to valuing humanity as the source of all value. I reconstruct Korsgaard's influential argument to show how she can resist many of the objections that critics have raised. I also show how the argument fails because, at a crucial point, it begs the question in favor of the value of humanity. It thus fails for internal reasons that do not depend on rejecting Korsgaard's metaethical constructivism or her conception of rational agency.