Immanuel Kant

Overview

Immanuel Kant (1724-1804) was a German Enlightenment philosopher whose critical philosophy distinguished what the mind can know only as it appears within its own categories of experience (“phenomena”) from “things in themselves” (“noumena”), placing God beyond the reach of theoretical knowledge.¹ Bavinck traces a shift in theology’s own working method to this move: “Since Kant declared God to be unknowable, reason and natural theology were substituted for divine revelation,” with “morality and religious feeling” becoming “the starting point and subject matter of theology.”¹ Two of the major theological responses to that shift, Friedrich Schleiermacher’s theology of feeling and G. W. F. Hegel’s absolute idealism, both took Kant’s agnosticism about theoretical knowledge of God as their departure point.²

Life and Ministry

Kant was born on April 22, 1724, in Königsberg, in the Prussian region of East Prussia, and spent his entire life in that city.³ He worked as a private family tutor for several years before completing his university studies, then lectured as an unsalaried Privatdozent at the University of Königsberg for fifteen years before his 1770 appointment to its chair of logic and metaphysics, a post he held until 1796.³ His major works include the Critique of Pure Reason (1781, revised 1787), the Groundwork of the Metaphysics of Morals (1785), the Critique of Practical Reason (1788), the Critique of Judgment (1790), and Religion within the Limits of Reason Alone (1793).³ He died in Königsberg on February 12, 1804.³

Theological Contribution

The limits of theoretical knowledge

Kant’s Critique of Pure Reason argued that theoretical reason can know objects only as they appear to the mind, structured by the mind’s own categories, and not as they are in themselves.¹ Applied to theology, this meant God, the soul, and the world as a whole could not be objects of theoretical knowledge at all.¹ Bavinck traces the effect on nineteenth-century theology to this starting point: Schleiermacher “shared Kant’s agnosticism” about theoretical knowledge of God and relocated religion in feeling instead, while Hegel rejected the agnosticism and offered dialectical philosophy as a different route to knowledge of the Absolute.²

Religion within the limits of reason alone

Kant relocated the content of religion in morality. Bavinck describes the shift plainly: “The content of religion and theology as Immanuel Kant develops it in his Religion within the Limits of Reason Alone is rationalistic and oriented toward morality; religion has become a means of achieving virtue.”² Bavinck traces the same voluntarist impulse in what he calls “the Kantian tradition,” which “defines religion voluntaristically as moral conduct and locates its seat in the human will,” adding that “there is a Pelagian impulse at work here in that faith is seen as a ‘new obedience’ achievable by human striving.”⁴

The postulates of practical reason

Kant held that although God, freedom, and immortality cannot be known by theoretical reason, they must be assumed as “postulates of practical reason” for the moral law to make sense. Bavinck summarizes the argument: the moral law “points us to an order above nature, a moral world order… If this imperative of duty is not an illusion but realizable… then freedom, and with it God and immortality, have to exist as well. These three, accordingly, are the postulates of practical reason; their reality is required by the moral law.”⁵ Kant himself put the point this way in the Critique of Practical Reason: “The person of integrity may say: ‘I will that there be a God; I will let no one deprive me of this faith. My moral interest demands the existence of God.’”⁵

Bavinck judges the theory unstable on its own terms: Kant’s distinction between the reason that issues the moral imperative and the reason that infers God’s existence from it requires “practical reason” itself to engage in the kind of logical inference Kant elsewhere reserves for theoretical reason, so that “the question arises: Why then is such a logical postulate not a matter of knowledge, not an element of theoretical reason?”⁵ Berkhof independently notes that Kant kept the doctrine of immortality on this basis even after rejecting the traditional arguments for it: “Kant stressed the untenableness of these arguments, but nevertheless retained the doctrine of immortality as a postulate of practical reason.”⁶

Critique of the theistic proofs

Kant argued that the traditional arguments for God’s existence fail to deliver the theoretical knowledge they claim to. Bavinck summarizes: “Under the critique of modern thought, notably Kant and Darwin, the ontological and teleological proofs have had a difficult time,” though he judges Kant’s parallel objection to the cosmological argument less persuasive, noting that “by itself this conclusion is perfectly legitimate, the criticism of Hume and Kant notwithstanding.”⁷

Berkhof gives Kant’s specific objections to each proof. Against the ontological argument (the inference from the idea of a perfect being to that being’s existence): “Kant stressed the untenableness of this argument, but Hegel hailed it as the one great argument for the existence of God.”⁸ Against the cosmological argument (the inference from an effect to its cause): “Kant pointed out that, if every existing thing has an adequate cause, this also applies to God, and that we are thus led to an endless chain.”⁸ Charles Hodge’s Systematic Theology devotes a dedicated section to “the Objections to the Teleological Argument… of Hume and Kant,” recording Kant’s own concession that the design argument, even granted, points at most to “a great architect” who arranged existing matter, not to a Creator who brought the world into being.⁹

Historical Significance

Bavinck frames Schleiermacher and Hegel as two competing answers to the same Kantian problem: Schleiermacher accepted Kant’s agnosticism about theoretical knowledge of God and moved theology’s foundation to religious feeling, while Hegel rejected the agnosticism and offered dialectical philosophy as a different route to knowledge of the Absolute.² Steven Duby engages the same epistemology in its more recent form, through Karl Barth’s rejection of natural theology, and concludes: “Christians have good reason to believe that Kant’s epistemology is flawed.”¹⁰ Craig Carter likewise traces Kant’s “antirealist epistemology” as a source later philosophers have credited with “undermining metaphysical realism” well beyond theology.¹¹

Related Doctrines

References

Herman Bavinck, Reformed Dogmatics: Abridged in One Volume, ed. John Bolt (Grand Rapids: Baker Academic, 2011), chap. 1, “Dogmatic Theology as a Science.” ↩ ↩² ↩³ ↩⁴
Bavinck, Reformed Dogmatics, chap. 2, “The History and Literature of Dogmatic Theology.” ↩ ↩² ↩³ ↩⁴
“Immanuel Kant,” Encyclopaedia Britannica, accessed September 8, 2026. ↩ ↩² ↩³ ↩⁴
Bavinck, Reformed Dogmatics, chap. 3, “Foundations of Dogmatic Theology.” ↩
Bavinck, Reformed Dogmatics, chap. 6, “Faith.” ↩ ↩² ↩³
Berkhof, Systematic Theology, 645. ↩
Bavinck, Reformed Dogmatics, chap. 7, “Knowing God.” ↩
Louis Berkhof, Systematic Theology (London: Banner of Truth Trust, 1969), 12. ↩ ↩²
Charles Hodge, Systematic Theology, Volume I (New York: Charles Scribner and Company, 1871), 227-28. ↩
Steven J. Duby, God in Himself: Scripture, Metaphysics, and the Task of Christian Theology, Studies in Christian Doctrine and Scripture (Downers Grove, IL: IVP Academic, 2019), chap. 2, “Preparation for the School of Grace,” 119. ↩
Craig A. Carter, “Do We Worship the God of the Bible?” in Contemplating God with the Great Tradition: Recovering Trinitarian Classical Theism (Grand Rapids: Baker Academic, 2021), chap. 9. ↩