Do we need the rules of religion in order to be good people? The German philosopher Immanuel Kant tackles this question in his 1793 text Religion within the Boundaries of Mere Reason. More than 200 years later, it is still a key text in the shaping of Western religious thought, as well as Kant’s most direct discussion of religious themes.

Kant tries to look at religious practices in relation to the Enlightenment movement—of which he was a part—and its firmly held beliefs in the power of reason and personal liberty.

He does not argue against religious belief itself, but against certain religious practices imposed by the Church. For Kant, true moral conduct doesn’t need such interference when human beings naturally know what is morally right.

The book was controversial because of Kant’s unorthodox views and resulted in a royal order requesting that he stop writing about religion, which he did—for several years.

Religion is still important for understanding Kant’s many ideas on moral philosophy and politics, freedom of expression, and religious belief.