 Many philosophers have maintained that altruism is a crucial component of morality, and that people often do behave altruistically. Other philosophers, along with many biologists and social scientists, have claimed that facts about human psychology, or about the evolutionary processes that have shaped human psychology, indicate that no human behavior is genuinely altruistic. Part of this disagreement can be traced to the fact that both philosophers and scientists use the term “altruism” with many quite different meanings. Sections 2, 3 and 4, set out a number of widely used accounts of altruism.  One of these, “the standard account”, has been the focus of most of the debate in philosophy over the existence of altruism. Sections 5 and 6, review some of the most important empirical work aimed at determining whether humans can indeed behave altruistically, on the standard account.