Abstract
Johann Salomo Semler's distinction between public and private religion has central significance for the theory of Christianity, particularly as this is conceived by Trutz Rendtorff. It serves the theory as a conceptual tool in order to be able to grasp the sociological problem of relating individual and society theologically and thus to describe modernity as a „chapter in the history of Christianity.“ Yet certain difficulties arise upon closer viewing. In Semler the distinction rests on the effort to set a free private religion apart from public religion. In this it is indebted to a pointedly critical interest and can thus not be enlisted in support of a constructive definition of the relationship between church and Christianity. As a result, it becomes difficult to claim that the theory of Christianity can be based upon the period of theological enlightenment. Instead, it is tempting to take up the critical starting impulse of Semler's distinction and interpret it as a figural reflection with which theology reflects its relation to its own subject matter. The distinction of public and private religion thus finally moves surprisingly close to a systems-theoretical version of the relationship between individual and society.