This dissertation defends the claim that it is a requirement of practical reason that we reason about ends. Accepting this requirement does not require rejecting the Humean theory of motivation or reason interrnalism. It is necessary because our motivational sets as they stand are often indeterminate and we must decide what kind of agent to be. This entails reasoning about ends because this self-conception must survive reflective scrutiny. To be a rational agent we must see ourselves as acting for reasons. By acting we commit ourselves to their being a rational justification of our action. All such justification must ultimately appeal to an end. This does not require that we be wholehearted concerning our ends. It can be entirely reasonable...