 David Velleman (2000) considers the idea that the key to understanding normativity in action is to discover what stands to action as truth stands to belief. It is constitutive of belief that it aims at the truth. Truth is normative for belief. That is, roughly, beliefs ought to be true, and a believer is subject to a requirement to be responsive to the truth. Similarly, perhaps, it is constitutive of action that it aims at the good. The good is normative for action. That is, actions ought to promote the good, and a person who acts is subject to a requirement to be responsive to the good. Velleman argues, however, for the different idea that it is constitutive of agency that agents have the aim of knowing what they are doing. Self-knowledge is the constitutive aim of action. Further, Velleman argues, this determines the criterion of success in action, which in turn determines which considerations count as reasons for action.