In this article, Korsgaard is concerned with agency. Agency is the ability to perform actions. Someone who can perform actions is an agent. Korsgaard describes two different kinds of theories about agency: the normative account and the natural account. On the natural account, an action is just what happens when there is a causal relationship between a belief and a behavior. This is a purely descriptive account. The normative account of agency is not purely descriptive. On the normative account, an action only happens if the agent's beliefs and actions are organized in a certain way. For example, Plato's account of agency includes the theory that an action is performed only if one's rational capacity is in control of the other parts of the person (spirit and appetite). Kant's account of agency includes the theory that an action is performed only when an agent reflectively considers the axiom that is guiding his action and then proceeds only if the axiom can be made universal law. Korsgaard thinks that any natural account of agency must also be supplemented with a normative account because only a normative account of agency can explain two implications that arise when we attribute agency.
When we attribute agency to someone, Korsgaard says there are two resulting implications. First, it seems like an action is somehow expressive of who a person is and the agent has some kind of ownership over his or her actions. She calls this the identity implication. In other words, actions express the identity of a person. Second, actions can fail in a way that simple causal linkages cannot. For example, the action of dodging a ball has a goal of avoiding being hit by a ball. Even if I move my body in response to a belief or desire, my action has failed if my goal has not been met. Korsgaard calls this the activity implication. Only a normative account of agency can help to explain these two implications.