This introduces and discusses the background to a virtually unknown text - Durkheim's speech at the funeral of his colleague and friend, Frédéric Rauh (1861-1909). The two men had known one another for some time, and had much in common. But a disagreement had arisen between them, over the individual's role in social life, and came to the fore in their exchange with one another during the debate on Durkheim's 'The Determination of Moral Facts' (1906). This traces the development of Rauh's career and of his views on ethics, outlines the argument of his main book, Moral Experience (1903), and indicates how his work increasingly referred to Durkheim, Lévy-Bruhl and the Année sociologique. But it is above all in an effort to pinpoint what was at stake. For it can seem more of a divergence of perspectives, generating disagreement over the questions it is important to ask, rather than over precisely the same issues.