Anthropology, along with other human sciences, often finds itself polarized between approaches that are primarily ‘social’ or ‘cultural’, and those that are primarily ‘biological’ or ‘evolutionary’. These approaches, in careless talk and in practice, are seen as mutually incompatible and opposed. Daniel Nettle, Ecole Normal Supérieure-PSI at Newcastle University, argued that the distinction should be given up: all social approaches are also biological, and biological approaches can also be social. There are not, in effect, two kinds of explanation for human life, but one kind with diverse details according to the case under consideration. Many people have made this point, going back many decades, but somehow it never quite gets a purchase. Nettle will spend the bulk of his lecture talking about why some kind of distinction between ‘biological’ and ‘social’ explanations manages to persist despite such good arguments for abandoning it. He will argue that the distinction is intuitive, based on patterns in human psychology, and therefore becomes an attractor. He will spend some time discussing what we might do to help ourselves give it up.