Abstract

One principal challenge to the rationalist thesis that the demands of morality are requirements of rationality has been that posed by the "rational egoist." In attempting to answer's the egoist's challenge, some rationalists have supposed that an adequate reply must take the form of a deductive argument that "converts" the egoist by showing that her position is contradictory, arbitrary, or violates some precept that defines practical rationality as such. Here I argue (a) that such rationalist replies will fail to persuade the egoist to adopt a recognizably moral way of life; (b) that this failure can be traced to epistemic assumptions that underlie typical rationalist replies; (c) that egoist conversion can better be understood by rejecting these assumptions and seeing egoist conversion as akin to a paradigm shift in the sciences; and (d) that conceptualizing egoist conversion as a paradigm shift accords with empirical psychological evidence regarding the acquisition and modification of individuals' moral attitudes and beliefs.