If there is room for a substantial conception of the will in contemporary theorizing about human agency, it is most likely to be found in the vicinity of the phenomenon of normativity. Rational agency is distinctively responsive to the agent's acknowledgment of reasons, in the basic sense of considerations that speak for and against the alternatives for action that are available. Furthermore, it is natural to suppose that this kind of responsiveness to reasons is possible only for creatures who possess certain unusual volitional powers, beyond the bare susceptibility to beliefs and desires necessary for the kind of rudimentary agency of which the higher animals are arguably capable.

But what exactly is the relation between normativity and the will? In this paper I want to discuss two contemporary answers to this question, both of which draw their inspiration from Kant. The first answer, due to Christine Korsgaard, holds that normativity itself must be accounted for in terms of the movements of the will. On the constructivist position that Korsgaard favours, what makes a given principle normative for me is my volitional commitment to comply with it in action. The primary role for the will in understanding rational action is thus to serve as what she calls the “source” of normativity, providing an account of what makes principles binding on us in the first place, as reasons for action. The second answer departs from Korsgaard's position in accepting a realist rather than constructivist framework for thinking about the normative principles that specify what we have reason to do.