This chapter retells the story of Darwin, the moral theorist. Although Charles Darwin himself neither used nor explicitly resisted the language of altruism, many others, from the 1870s to the present, have made claims about Darwin as a theorist of altruism and selfishness. Darwin, in fact, saw sympathy and love, alongside selfishness and violence, throughout the natural world. In insect societies as well as human ones, cooperation and benevolence had evolved for good reasons. The theory of the evolution of the moral sense that Darwin developed in The Descent of Man (1871) was complicated and not entirely ‘Darwinian’. It combined ideas from moral philosophy with observations of the instincts of insects, all within a theoretical framework that included a belief in the heritability of acquired characteristics and the ability of nature to select at the level of communities as well as individuals.