In the preceding chapters I have shown that in arguing for the social causes and functions of the categories, Durkheim was responding to the way that the Kantian categories were understood in the eclectic spiritualist tradition. Kant's logically necessary conditions of experience were understood as psychologically necessary conditions, which led to the subjectivist reading of the critical philosophy according to which it was unable to explain or justify the application of the categories to our experience of the external world. The eclectic spiritualists then sought an epistemological grounding of the categories in an empirical apperception of the mind's activity, rather than in Kant's transcendental deduction of the categories, in which the transcendental apperception of the unity of consciousness plays a central role. Among the early eclectic spiritualists, the theory of the categories was thus thought to belong to a foundational introspective psychology.

During the late nineteenth century in France, however, psychology increasingly came to be seen as an empirical, hypothetico-deductive science. Durkheim's purpose was to show that a theory of the categories should rightfully belong to an empirical sociology instead. To make sense of his arguments, however, we have had to introduce a distinction between the categories and their collective representations. With this distinction in mind, we can then extract two different theses from his sociology of knowledge: (1) that there is a set of categories that is found in all human cultures because they are necessary to the moral rules and obligations that hold individuals together in a society; and (2) that a person's ways of thinking and communicating about these concepts are acquired from his or her culture.