|dc.description.abstract||The main goal of this thesis is to shed some light on the nature of reasons to act, and the nature of the relationship between morality and reasons to act, through a defense of rational egoism. Rational egoism holds that an agent's reasons to act are grounded by his self-interest, which is conceived as something different from, and not relativized to, his desires. In other words, for a rational egoist, an agent is rational if he does what is, in fact, good for him. I develop a version of rational egoism, and then argue that my version of rational egoism is at least as viable as, if not preferable to, other theories about the nature of reasons to act, and the nature of the relationship between morality and reasons to act. I claim that rational egoism provides a uniquely compelling account of the nature of reasons to act, and the nature of the relationship between morality and reasons to act. The rational egoism that I endorse treads a sort of theoretical middle ground between its most compelling competitor theories, capturing their theoretical merits and yet avoiding the problems that they are vulnerable to. One of rational egoism's most compelling competitor theories holds that it is morality itself that necessarily provides agents with reasons to act. This theory, known as intrinsic moral rationalism, and advanced by Russ Shafer-Landau, is most compelling for its compatibility with moral convention, but is troubled in that it seems to confer upon morality a mysterious force that allows it to impose upon agents. I will argue that my rational egoism is also compatible with moral convention, and yet not mysterious in the troubling way that intrinsic moral rationalism is. The other of rational egoism's most compelling competitor theories, which I refer to as the desire-satisfaction view, holds that it is an agent's desires, in some sense, that necessarily provide agents with reasons to act. In its most basic form, the desire-satisfaction view holds that it is an agent's actual desires that necessarily provide him with reasons to act. More sophisticated versions of the desire-satisfaction view, like Bernard Williams' view, for example, hold that an agent's desires, qualified in some way, necessarily provide him with reasons to act. The desire satisfaction view, in general, is most compelling for the prominence it gives desires, yet troubled by its commitment to the proposition that even an agent's desires for things that are cruel, self-destructive, or meaningless, nonetheless provide the agent with reasons to act. And although Williams' view and other sophisticated versions of the desire-satisfaction view may be able to get out of this commitment, it would take too much unmotivated theoretical machinery for them to do so. I will argue that my rational egoism also gives due regard to desires, yet avoids the troubling commitment of the desire-satisfaction view, and does so without appeal to any unmotivated theoretical machinery. My rational egoism is not, itself, necessarily committed to one particular view regarding the nature of the relationship between morality and reasons to act. However, I strongly suspect that if rational egoism is true, then there is always, or almost always, a reason to do the moral thing. On one normative moral theory, namely moral egoism, morality just requires agents to do that which is in their self-interest. If moral egoism is true, and there are indeed grounds for believing that it is, and rational egoism is true, then there will always be a reason to do the moral thing. But even if moral egoism is not true, I argue that there are solid grounds for believing that morality usually indicates that agents should do that which is in their self-interest. In this case, if rational egoism is true, there will usually be a reason to do the moral thing.