Kant holds that the origin of our propensity to evil arises in connection with our unsociable sociability. The effective response to it, therefore, must also be social. We must leave the ethical state of nature and join with others in voluntary ethical community, where our shared ends, conceived as the highest good, under the legislation of a divine lawgiver will promote moral progress among human beings. The existing communities of this kind are churches and ecclesiastical faiths, which fall short of their religious vocation but can and should be reformed so as to live up to it. The relation of rational religion to revealed religion is therefore intended by Kant to be dynamic, with the interpretation of revealed religion enriching rational religion and the reform of revealed religion bringing rational and revealed religion into closer harmony, leading gradually toward the founding of the Kingdom of God on earth.

Kant is critical of many of the practices of Christianity in his time. But when we appreciate the dynamic relation between rational and revealed religion as Kant conceives them, the apparent opposition becomes more questionable and raises more questions than it answers. Kant’s project in the Religion bears important affinities with the religious philosophy of Moses Mendelssohn. Mendelssohn’s philosophy of church and state and their relation involve a number of radical proposals expressive of Enlightenment religious consciousness. Mendelssohn’s concept of enlightened Judaism bears interesting comparison to Kant’s enlightened reflections on Christianity. Mendelssohn defends a form of evidentialism even more radical that Clifford’s. He also defends a conception of the freedom of religious conscience that inspires Kant’s treatment of that topic in part four of the Religion. Conscience is an important theme in Kant’s moral philosophy, which has special application to religious conscience and the freedom of conscience Kant and Mendelssohn both defend.