For a long time, Kant's natural religion has been viewed with suspicion by scholars of his work. In particular, his theory of radical evil and the conception of grace have been widely objected. The purpose of this work is to show the internal coherence of natural religion and its harmonious fit in the Kantian critical project.

Kant published, in 1793, the religion within the limits of the mere reason, its more important writing on philosophy of the religion. In this work he expounded his ideas about "natural religion," the only religious doctrine in which reason can be used in itself, without appealing to the authority of revelation.

The method chosen by Kant is to find out to what extent the dogmatic contents of Christianity and the teachings of the Bible can be reconstructed and assumed by autonomous reason. Proceeding in this way, Kant will come to propose rational doublets of many of the contents of positive religion under consideration.