This essay examines Durkheim's functionalism, to argue that it cannot be adequately understood through later movements of structural functionalism, especially Parsonian functionalism. Concretely, for Durkheim, the function of the division of labour is to create solidarity but this runs into the problem of modern pathologies. More abstractly, his functionalism has two essential sets of components, and it is only through the relation between these that it is possible to grasp his argument and its full significance. One involves ideas of correspondence, tendency and action, so that function has to do with a set of 'living movements' and how it corresponds with social needs. The other involves a functionalism of mind, and above all centres round the idea of conscience as a set of epistemological, representative and practical functions. Durkheim's functionalism relates these two components in a concern with the power of critical reflection on existing patterns of society, and with how conscience releases the force of agency, to have a transformative potential on the ills of society.