Many philosophers believe there is a principle of practical reason directing the individual to maximize the satisfaction of his own interests. This belief is supposedly compatible with the views that all practical reasons are instrumental and all motivation is grounded in desire. Against these claims, this chapter argues that the only possible normative foundation for the egoistic principle (or principle of prudence) would be a rational intuition that maximum satisfaction is the Good; that motivation to conform to the egoistic principle would have to rest in pure practical reason; and that the only coherent formulation of the egoistic principle depends on controversial psychological assumptions characteristic of 18th-century British empiricism.
Keywords: desire, egoism, empiricist, instrumental, motivation, normativity, prudence, rationalist, reason, satisfaction