 The remaining three books of the Prolegomena concern issues in moral psychology and ethical theory. Green criticizes forms of ethical naturalism that attempt to ground morality in a science of desire and pleasure. In particular, he targets those in the utilitarian tradition who defend hedonism. He rejects the hedonist conception of motivation, arguing that moral agents have capacities for practical reason that allow them to distinguish between the intensity and authority of their desires, to deliberate about their desires, and to regulate their action in accordance with their deliberations. Agents needn’t act on their strongest desires; they can and should act on the basis of a judgment about what it is best for them to do. This, Green claims, is to act on a conception of one’s own overall good. Here, Green aligns himself with the Greek eudaimonist tradition, which he interprets in terms of self-realization. Because Green derives the demand for self-realization from an understanding of agency itself, he regards its demands as categorical, rather than hypothetical, imperatives. Self-realization for Green requires self-consciousness, which requires proper cognizance of others. In this way, he agrees with those Greeks, such as Aristotle, who claim that the proper conception of the agent’s own good requires a concern with the good of others, especially the common good. However, Green thinks that the Greeks had too narrow a conception of the common good. It is only with Christianity and enlightenment philosophical views, especially Kantian and utilitarian traditions in ethics, Green thinks, that we have recognition of the universal scope of the common good. This leads Green to claim that full self-realization can take place only when each rational agent regards all other rational agents as ends in themselves on whom his own happiness depends. In such a state, there can be no conflict or competition among the interests of different rational agents. Green links self-realization and freedom; freedom is best understood in terms of self-determination and self-realization. Because Green thinks that self-realization aims at the common good, he thinks that freedom also aims at the common good. Green concludes that moral progress consists in the gradual realization of this sort of freedom, which requires the progressive realization of the common good.