 A brief sketch of the most complete and influential contemporary contractarian theory, David Gauthier’s, is in order. Gauthier’s project in Morals By Agreement is to employ a contractarian approach to grounding morality in rationality in order to defeat the moral skeptic. (However, Anita Superson (2009) points out that Gauthier attempts to answer only the skeptic who asks “why should I be moral?” but leaves both the motive skeptic, who argues that it is enough to act morally but need not be motivated by morality, and the amoralist, who denies that there is any such thing as morality, that is, that there are true moral statements.)  It is generally assumed that humans can have no perfect natural harmony of interests (otherwise morality would be largely superfluous), and that there is much for each individual to gain through cooperation. However, moral constraint on the pursuit of individual self-interest is required because cooperative activities almost inevitably lead to a prisoner’s dilemma: a situation in which the best individual outcomes can be had by those who cheat on the agreement while the others keep their part of the bargain. This leads to the socially and individually sub-optimal outcome wherein each can expect to be cheated by the other. But by disposing themselves to act according to the requirements of morality whenever others are also so disposed, they can gain each others’ trust and cooperate successfully. 