Against readings that have emphasized Durkheim's sociological realism and reductionism, this article examines the role of individuality and psychology in his theory. In particular, Durkheim's approach to representations is the proof of the crucial importance he assigned to mental processes in the construction of social life. Durkheim showed the relation of representations to the collectivity – how ideas promote the sense of community – and in this context he emphasized their epistemological ramifications. Specifically, he pointed to a series of dualisms that remained unexplained by psychological analysis, including the one posing rational against affective logic. While arguing for the preeminence of ideas in Durkheim's view of society, the article also recognizes the limitations that marred his efforts at reconciling the individual with society. Most notably, his genetic approach and his account of the central role of affect in the creation of the social made Durkheim vulnerable to criticism. Even his late essay on the dualism of human nature, which testifies to his lifelong confrontations with psychology, left a whole set of questions unanswered about his theory's applicability to historical forms of institutionalization of the social, especially in modernity.