Kant’s religious ethics: the ineluctable link between morality and theism


Kant’s religious ethics is grounded in a practical philosophy where ‘God’ is subordinated to moral principles. To accomplish this goal, Kant dismantled the onto-theological groundwork of religion and the conventional method of attaching morality to God, as if morality was a consequence of religious belief. In this essay, I will show how Kant replaces the metaphysics of being with the metaphysics of morality. More importantly, I will show how Kant’s thesis of moral theism argues that the practical philosophy does not end with the categorical imperative, but that Kant also thinks morality inevitably leads to religious belief.

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  1. 1.

    I am referring to Beck’s sardonic rephrasing, “The Critique seems to be suspended from nothing in heaven and supported by nothing on earth,” and Pippin’s sardonic inversion of the same line—“supported by nothing on earth and suspended from nothing in heaven”—are starkly opposed to Pacini’s portrayal of Kant’s new metaphysical project as a response to the modern experience of loss. See Lewis White Beck 1978. Essays on Kant and Hume. New Haven: Yale University Press. Robert Pippin. 1999. Modernism as a Philosophical Problem: On Dissatisfactions of European High Culture. Oxford: Blackwell. Pacini’s 2008. Through Narcissus’ Glass Darkly: The Modern Religion of Consciousness. New York: Fordham University Press.

  2. 2.

    This is the kind of language used by Pacini (2008), and also by Dieter Henrich in his wildly popular book Between Kant and Hegel: Lectures on German Idealism (2003).

  3. 3.

    Note the unique character of the phrase “outside the human being”. It points to an outside of the human being, but it does so from the position of the human being. Therefore, it is an undecided question if the ‘outside’ marks a line (that cannot be transgressed) or a boundary (that can be looked at from the other side). The latter interpretation seems to be the correct path to take when considering the title of Kant’s Religion within the Boundaries of Mere Reason.

  4. 4.

    This way of interpreting Kant is still very commonplace, which is supported by the fact that the 2016 Stanford Encyclopedia of Philosophy article on Immanuel Kant devotes an entire section to explain “Kant’s Copernican revolution in philosophy”. In this section, the author argues that Kant’s overarching goal in the CpR is “reconciling modern science with traditional morality and religion”. https://plato.stanford.edu/entries/kant/#KanCopRev (Accessed September 8, 2019). What I am arguing is that Kant believes he is offering up an entirely new idea of religious belief, one which cannot be reconciled with natural philosophy but does not in any way substantially contradict it or create disharmony.

  5. 5.

    There has been multiple iterations of the debate over Kant’s Copernican analogy in the preface that go back as far as Norman Kemp Smith’s commentary on the CpR released in 1918 to as recently as an article by Miles Murray’s “Kant’s ‘Copernican Revolution’: Toward Rehabilitation of a Concept and Provision of a Framework for the Interpretation of the Critique of Pure Reason” in the Kant-Studien, vol. 97 (2006).

  6. 6.

    This interpretive conflict (resolve vs. dissolve) is the same conflict that arises in trying to call Kant a ‘modern thinker’ or a ‘post-modern thinker’. Each designation depends on the canon of readers we put side-by-side with Kant. On the one hand, he is read with Descartes, Leibniz, Hume, and Locke making him one of the last voices of the original Enlightenment philosophers. While, on the other hand, he is read alongside Hobbes, Rousseau, Hegel, Fichte, and Schelling bringing him closer to late modern and post-Enlightenment thinking. Many more canons can be devised which traditionally include his works. Inevitably it is best to situate Kant as the writer between the early moderns and everything after. He must be read in both directions.

  7. 7.

    Jane Kneller makes an insightful claim that Kant takes up a precarious position “to suspend the Copernican turn in order, for the sake of practice, to make the bald metaphysical claims of the postulates”. See Kneller, Jane, Kant and the Power of Imagination, Cambridge: Cambridge University Press, (2009). In a similar way, I am arguing that Kant’s metaphysical turn suspends theoretical reason from expounding the postulates, and, as such, he turns toward practical reason and the metaphysics of morality to lay the groundwork for religious discourse.

  8. 8.

    It is reasonable to ask why Kant did not cut off metaphysics from a nominal demonstration at all. While it is strange that Kant does not cut off metaphysics from the possibility of a demonstration in the OpA, this openness to a possible demonstration of God’s existence seems to come more from a place of humility than any other agenda. Or perhaps it is simply a survival tactic.

  9. 9.

    This is a reference to Q.E.D. (quod erat demonstrandum). This phrase has etymological roots going as far back as the Greeks. However, with Kant’s background in classical education it is likely that he has the Latin instance of the phrase in mind. The literal Latin translation in English is “what was to be demonstrated.” Colloquially, it means that the conclusion follows from the premises through logical necessity, and is, therefore, demonstrably true, i.e., logically valid and sound.

  10. 10.

    Here I am thinking of the works of Post-Structuralist philosophers like Jean-Francois Lyotard.

  11. 11.

    For more see Robert Hanna’s “Kant’s Theory of Judgment” entry in the Stanford Encyclopedia of Philosophy (2017), which explains the difference between a priority and a posteriority, as well as, explains the difference between synthesis and analysis with a refreshing clarity.

  12. 12.

    etwas Existirendes ist Gott.

  13. 13.

    It is important to point out Kant’s own prejudice. While Kant was troubled by the way that Christianity was used to justify religious ethics and various systems of morality, which he thinks are wrong-headed and not in keeping with the enlightenment principles of freedom and autonomy. He is also deeply prejudice in Anthropology from a Pragmatic Point of View towards women, who were not treated as equals, and the African peoples, who were being abducted and traded for enslavement (Kant 2006).


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Perrier, R.E. Kant’s religious ethics: the ineluctable link between morality and theism. Int J Philos Relig (2020). https://doi.org/10.1007/s11153-020-09765-9

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  • Kantian ethics
  • Theory of judgment
  • Metaphysics of morality
  • Religious ethics
  • Religious theory of belief
  • Moral epistemology