IN the state of nature, nobody cares about other people. Fortunately, we do not live in this dismal state. Sometimes we take account of other people's success and well-being and are willing to sacrifice some of our own for their sake. Or so it appears. But perhaps altruistic behavior really springs from self-interest. For instance, isn't it in my long-term self-interest to help others, so that I can receive help in return when I need it? Isn't the patron of a charity motivated by his own prestige rather than by the needs of the beneficiaries? What matters to him is that his donations be visible and publicized, not who benefits from them. Some might argue (see chapter II) that people are always and everywhere motivated by self-interest and that differences in behavior are due only to differences in their opportunities. Civilized society, on this view, depends on having institutions that make it in people's rational self-interest to speak the truth, keep their promises and help others – not on people's having good motivations.

I believe this argument is plain wrong, and I shall explain why in a moment. Let us first, however, get a few things out of the way. The proposition that self-interest is fundamental could be understood in two ways other than that just set out. It could mean that all action is ultimately performed for the sake of the agent's pleasure or that self-interest has a certain methodological priority.