Ostensibly, Hume’s Essays do not have much to say about religion. ‘Of Superstition and Enthusiasm’ (1741) may contain an incisive treatment of the psychological origins of religious error and its ecclesiastical and political consequences, but it was the one Essay dedicated to religion published in Hume’s lifetime. But when the topic of religion does come up in the Essays, as it frequently does in examples, asides and footnotes, we find Hume doing two things: outlining the character and dangers of institutional religion on individual happiness and social stability and doing so in a neutral manner characteristic of his wider ‘science of man’. He brought religious belief and priestly power down to the level of another aspect of human life, comparable to the other themes discussed in this guide, and which could subject to ‘scientific’ observation that led to identification of general principles. Piecing together the various discussions of religion, we find Hume articulating a strong anticlericalism in which religion is understood to be a natural propensity of human nature, exploited by priesthoods claiming power over others, but which could be managed through increased scepticism about clerical claims amongst the citizenry and the subordination of church to state.

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.