Abstract

This dissertation addresses the relation between obligation and motivation. On the assumption that "ought implies can" and when the requirements of explanation are taken to follow the principle of sufficient reason, this relation is widely taken to be problematic. The moral agent cannot have an obligation unless she is able to act on it and unless she has a sufficient reason to act, for if she has no sufficient reason, she may ask why she should do the requisite act and get no answer. But if the sufficient reason does not give her a sufficient motive, then she would be unable to act for that reason; and so she would be excused from doing what she has a sufficient reason to do. ;There are two separate questions that are raised by the above analysis. First, what kind of answer is it appropriate to give the agent when she asks why she should do the act? Second, how does this answer make the action psychologically possible? This dissertation focuses on the second of these questions. On the traditional assumption that the human agent desires only her own good, the latter problem becomes that of showing that doing one's duty necessarily advances one's own good. Unfortunately, it does not. ;Following Kant, I argue instead that our obligations categorically constrain our power to act, in that these constraints do not depend on our own good or our inclinations. The latter part of this Kantian claim apparently conflicts with the widely held thesis of internalism, the view that a reason to act necessarily motivates the agent to act. ;Typical statements of internalism accept the Humean orthodoxy that all motivations are wants, and thus conclude that only desires provide reasons to act. I suggest that this desire-based version of internalism displays a narrow-minded view of mental causation and propose a different version of internalism, a reasons-centered internalism which recognizes that desires are not the only internal contribution of the agent compatible with practical agency. A reasons-centered internalist can hold, correctly, that certain of the agent's beliefs can explain that agent's acting even without reference to desires. I argue that a reasons-centered internalism can account for the categorical character that the phenomenon of obligation exhibits whereas a desire-based account cannot