One of the most noteworthy features of David Gauthier's rational choice, contractarian theory of morality is its appeal to self-interested rationality. This appeal, however, will undoubtedly be the source of much controversy and criticism. For while self-interestedness is characteristic of much human behavior, it is not characteristic of all such behavior, much less of that which is most admirable. Yet contractarian ethics appears to assume that humans are entirely self-interested. It is not usually thought a virtue of a theory that its assumptions are literally false. What may be said on behalf of the contractarian?