Physically he was one of the smallest men of his time—just a little above five feet in height, and made still shorter by a forward curvature of the spine. His lungs were weak, his stomach ailed; he survived only by a regular and abstemious regimen. It was characteristic of him that at seventy he wrote an essay “On the Power of the Mind to Master the Feeling of Illness by Force of Resolution.” He stressed the wisdom of breathing through the nose; one could avoid many colds, and other mishaps, by keeping his mouth shut.90 So, in his daily walks, he walked alone, shunning conversation. He went to bed punctually at ten, rose at five, and in thirty years (he assures us) never overslept.91 Twice he thought of marriage, twice he retreated. But he was not unsociable; usually he invited one or two guests, most often his pupils—never any woman—to share his dinner at 1 P.M. He was a professor of geography, but rarely moved outside Königsberg; he never saw a mountain, and probably—near though it was—never saw the sea.92 He was sustained through poverty and censorship by a pride that only outwardly yielded to any authority other than his own reason. He was generous, but he was severe in his judgments, and lacked that sense of humor which should save philosophy from taking itself too seriously. His moral sense rose at times to an ethical pedantry that held all pleasures suspect until they had proved themselves virtuous.

He cared so little for organized religion that he attended church only when his academic functions required it.93 He seems never to have prayed in his mature life.94 Herder reported that Kant’s students based their religious skepticism on Kant’s teaching.95 “It is indeed true,” Kant wrote to Mendelssohn, “that I think many things with the clearest conviction, and to my great satisfaction, which I never have the courage to say, but I never say anything that I do not think.”96

Till his last years he strove to improve his work. In 1798 he told a friend: “The task with which I now busy myself has to do with the transition from the metaphysical basis of the natural sciences to physics. This problem must be solved, or otherwise here is a gap in the system of critical philosophy.”97 But in that letter he described himself as “incapacitated for intellectual work.” He entered into a long period of physical decline, accumulating ailments, and the loneliness of unmarried old age. He died on February 12, 1804. He was buried in the Königsberg cathedral, in what is now known as the Stoa Kantiana; and over his grave were inscribed his words, “The starry heavens above me; the moral law within me.”

At his death he left a confused mass of writings which were published as his Opus postumum in 1882-84. In one of these he described the “thing-in-itself”—the unknowable substratum behind phenomena and ideas—as “not a real thing, … not an existing reality, but merely a principle … of the synthetic a priori knowledge of the manifold sense-intuition.”98 He named it a Gedankending, a thing existing only in our thought. And he applied the same skepticism to the idea of God:

God is not a substance existing outside me, but merely a moral relation within me. … The categorical imperative does not assume a substance issuing its commands from on high, conceived therefore as outside me, but is a commandment or a prohibition of my own reason. … The categorical imperative represents human duties as divine commandments not in the historical sense, as if [a divine being] had given commands to men, but in the sense that reason … has power to command with the authority and in the guise of a divine person. … The Idea of such a being, before whom all bend the knee, etc., arises out of the categorical imperative, and not vice versa. … The Ens Summum[Supreme Being] is an ens rationis [a creation of reason], … not a substance outside me.99

So the Kantian philosophy, to which Christianity clung so long, in Germany and later in England, as the last, best hope of theism, ended in a bleak conception of God as a useful fiction developed by the human mind to explain the apparent absoluteness of moral commands.

Kant’s successors, not knowing his Opus postumum, acclaimed him as the savior of Christianity, the German hero who had slain Voltaire; and they magnified his achievement until his influence exceeded that of any other modern philosopher. One disciple, Karl Reinhold, predicted that within a century Kant’s reputation would rival that of Christ.100 All Protestant Germans (except Goethe) accepted Kant’s claim that he had effected a “Co-pernical revolution” in psychology: that instead of having the mind (the sun) revolve around the object (the earth) he had made the object (things) revolve around—and depend upon—the mind. The human ego was flattered by being told that its intrinsic modes of perception were the determining constituents of the phenomenal world. Fichte concluded (even before Kant died) that the external world is a creation of the mind, and Schopenhauer, accepting Kant’s analysis, began his massive treatise The World as Will and Idea with the announcement “The world is my idea”—which rather surprised Mme. de Staël.

Idealists rejoiced that Kant had made materialism logically impossible by showing mind to be the only reality directly known to us. Mystics were happy that Kant had restricted science to phenomena, had barred it from the noumenal and really real world, and had left this shady realm (whose existence he secretly denied) as the private park of theologians and philosophers. Metaphysics, which the philosophes had banished from philosophy, was reinstated as the judge of all science; and Jean Paul Richter, conceding mastery of the sea to Britain, and of the land to France, assigned to Germany the mastery of the air. Fichte, Schelling, and Hegel built metaphysical castles upon the transcendental idealism of Kant; and even Schopenhauer’s masterpiece took its start from Kant’s emphasis upon the primacy of the will. “See,” said Schiller, “how a single rich man has given a living to a number of beggars.”101

German literature, too, soon felt Kant’s influence, for the philosophy of one age is likely to be the literature of the next. Schiller buried himself for a while in Kant’s tomes, wrote a letter of homage to their author, and, in his prose essays, achieved an almost Kantian obscurity. Obscurity became a fashion in German writing, a coat of arms attesting membership in the ancient order of web weavers. “On the whole,” said Goethe, “philosophical speculation is an injury to the Germans, as it tends to make their style vague, difficalt, and obscure. The stronger their attachment to certain philosophical schools, the worse they write.”102

One would not readily think of Kant as romantic, but his learned-hazy passages on beauty and sublimity became one of the founts of the Romantic movement. Schiller’s lectures at Jena, and his Letters on the Aesthetic Education of Mankind (1795)—milestones in that movement—grew out of studying Kant’s Critique of Judgment. The subjectivist interpretation of Kant’s theory of knowledge gave a philosophical basis to the romantic individualism that flaunted its flag in Sturm und Drang. The Kantian literary influence crossed to England, and affected Coleridge and Carlyle; it crossed to New England and gave a name to the Transcendentalist movement of Emerson and Thoreau.103 The bent little professor of geography shook the world as he trod the “Philosopher’s Walk” in Königsberg. Certainly he offered to philosophy and psychology the most painstaking analysis of the knowledge process that history has ever known.

If you find an error or have any questions, please email us at Thank you!