In what sense do social phenomena exist? Durkheim was the first to argue that this question was foundational to sociology. He argued that if only individuals exist, “Sociological laws can be only a corollary of the more general laws of psychology; the ultimate explanation of collective life will consist in showing how it emanates from human nature in general” ([1895] 1964, 98). As we saw in Chapter 3, most philosophers of the nineteenth century held to either utilitarian atomism (in which sociology is ultimately reducible to psychology) or metaphysical organicism. Durkheim proposed a third path: a scientific sociology that could not be connected in any systematic way to psychological phenomena. To many of his contemporaries, this seemed to be an unresolvable dilemma: One was either a scientist and accepted that society was reducible to individuals, or else one was proposing a metaphysical dualism. In this chapter I present a new perspective on how Durkheim resolved this dilemma. I interpret Durkheim as a theorist of social emergence, the first sociologist to elaborate Comte's original insights (see Chapter 3). I argue that the central guiding premise that unifies all of Durkheim's work is the attempt to account for both the emergence of the social from the individual and downward causation from the social to the individual.