The following chapter proposes to examine the conception of the mass that runs through Freud’s work with particular reference to the analysis of religion that is developed in the essays on application. In The Future of an Illusion (1927), this reflection leads to the hope that, one day, science will take over from religious ideas. This prediction rests on a traditional apportioning whereby ignorance and superstition are the lot of the many while enlightenment through science the prerogative of the few. The psychoanalytic examination of religion does not entirely modify this view, it could even be said to reinforce it. Our purpose, however, is less to insist on the pejorative view on ‘the great number’ that psychoanalysis undeniably holds than to explore the way in which the scientific activity that psychoanalysis aims to constitute cannot easily make room for ‘the many’. It is mostly as far as the future science at issue in The Future is above all the psychoanalytic science of the mind, whose object of study is a psychical apparatus that the incompatibility between science and ‘the many’ takes its full importance. An overview of the apparently only ‘social’ concept of the mass that runs through Freud thus leads us to the core of the psychoanalytic project, by confronting us with the ‘delicate apparatus of the mind’, whose operations are not easily conceivable on a large scale.