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Immanuel Kant and the “Crisis of the Enlightenment”

I had to deny knowledge in order to make room for faith. —Immanuel Kant
Contemporary history has bestowed upon Immanuel Kant (1724–1804) such titles as “the greatest philosopher in history,” “one of the most influential figures in modern Western philosophy,” and “one of the central Enlightenment thinkers.” Kant arrived on the Enlightenment “scene” fairly early, but he did his chief work in midlife and after, producing book after book, elaborating his ideas until he died a decade after the French Revolution—commonly viewed as the closing scene of the Enlightenment as a dominant intellectual movement.
Thus, Kant addressed himself to philosophical debates that had evolved through decades of the Enlightenment—the nature of knowledge, the possibility of certainty, the possibility of a reasoned morality, the reality of free will, the existence of God—great unresolved questions hanging over educated Europe—and provided answers to them within an integrated system. Above all, he adopted as his rallying cry, his motto or byword, the term that defined the Enlightenment: reason. He marched always under that banner, using “Reason” repeatedly in titles of his books.
Whether or not he intended to uphold reason in its Enlightenment sense, or succeeded in defending it,  he undoubtedly grasped and exploited a truth that has persisted to this day in the realm of ideas. You cannot successfully advance—or attack—any idea unless you do so in the name of reason. In particular, you cannot successfully attack and undercut reason except in the name of reason. In the centuries since Kant, centuries characterized by attacks on every fundamental Enlightenment cause—secularism, science, individualism, political freedom, free markets, objectivity, and reason itself—these attacks with comparatively few exceptions have been in the name of reason.
This is easier to observe today in the sciences. At least in developed nations shaped by the Enlightenment, no theory, proposal, policy, or opinion asserting a truth about nature, including human nature, can win any consideration if it disregards science. However we may estimate the nature and extent of Kant’s broad contemporary influence, he can claim paternity of this descendant of his work. 
What innovative ideas did Kant inject into the mainstream of European, American, and, progressively, world philosophy? Whenever that question is posed, it is followed by an immediate qualification, a caution, or even an apology. Immanuel Kant, if the most important of our philosophers, is also the most difficult. The logic and style—not to mention the length—of his books in German are reported to have repelled readers from the outset. It even seemed, if briefly, that his most famous contribution—the Critique of Pure Reason (1781)—might be defeated by its unreadability.
That did not happen. Kant wrote for decades, dutifully, obsessively, and things got better. Not necessarily his style, but his frequent reiteration of his positions and his reputation won interpreters, advocates in the professoriate, and translators.
Kant’s Life in Brief
But first, what is the story of the life behind the ideas?
Kant was one of nine children born into a Lutheran Protestant family shaped by pietist religious devotion. His father, a harness maker, was strict, his teaching of the Bible literal. Kant’s upbringing and early education were disciplined to the point of punitive; the early emphasis of his studies was on religious devotion and Latin, certainly not mathematics or science. Nothing dimmed Kant’s early, powerful aptitude for study. Graduated from a local “collegium” (in France, middle and high school), he entered the University of Königsberg at sixteen. He remained at the university and lived in Königsberg his entire long life. His self-discipline only increased with time, so that a famous remark is that the townspeople could set their clocks by his daily walks. He did not marry but enjoyed popularity as a teacher and author even before embarking on philosophy. 
At the university, his mentor, Martin Knutzen, although a rationalist, took pains to introduce Kant to British empiricism, the chief theory of knowledge (along with rationalism) shaping the Enlightenment, and to the new mathematical science of Isaac Newton. He also discouraged Kant from both the extreme German rationalism of Wilhelm Leibniz and the extreme “idealism” of Irish philosopher George Berkeley, with his claim (arguing against John Locke) that the only “reality” is what exists in our minds.
There followed decades when Kant did notable work in physics, astronomy, geology, natural law, anthropology, and ethics, steadily writing and publishing. He could not at first get a professorship at the University of Königsberg. He made his living tutoring, teaching at another local university, and, for fifteen years, offering a weekly public lecture series under license from the University of Königsberg for which students and the public paid to attend. In the early 1760s, Kant began working in philosophy with equally notable industry, becoming a popular author. But it was not until 1770, when Kant was forty-six, that he finally was made Full Professor of Logic and Metaphysics at the University of Königsberg and never left.
The Crisis of the Enlightenment
Immediately, in his inaugural dissertation, he launched into such themes as the distinction between intellectual thought and the receptivity of sensations that would inform his work from then on. As a scholar and known philosopher in a distinguished post, he was under pressure to produce. The problem he set himself to solve was skepticism, an Enlightenment brand of skepticism arising from strict adherence to the principle that we know nothing beyond what we experience. 
For bringing home to him that challenge, and its full implications, Kant gave credit to Scottish Enlightenment philosopher David Hume in his famous admission that Hume, in his 1739 Treatise on Human Nature, awakened him from his “dogmatic slumber”—from settled belief in the certainty of both religion and natural philosophy (science). If we know only what we experience directly, then how can we claim any certain knowledge of causality, morality, God, or even objects?
This was where the debates of Enlightenment thinkers had led. Locke had argued that our sense impressions and ideas are how we are aware of reality and understand it. George Berkeley had responded that, on the evidence, all that exists are our sense impressions and ideas; we have no idea if there is a reality, an “out there,” corresponding to the contents of our minds. And Hume had argued that, limited to our impressions and ideas, we cannot be certain that anything else exists—neither the world described by science nor the world described by faith. This has been characterized as one key to the “crisis of the Enlightenment” that confronted philosophers of Kant’s time. The Stanford Encyclopedia of Philosophy offers this overview:
“The Enlightenment was a reaction to the rise and successes of modern science. . . . [Its] spectacular achievements . . . engendered widespread confidence and optimism about the power of human reason to control nature and to improve human life. One effect . . . was that traditional authorities were increasingly questioned. . . .

“The problem is that to some it seemed unclear whether progress would in fact ensue . . . or whether unaided reasoning would instead lead straight to materialism, fatalism, atheism, skepticism. . . . The Enlightenment commitment to the sovereignty of reason was tied to the expectation that it would not lead to any of these consequences. . . . Crucially, these included belief in God, the soul, freedom, and the compatibility of science with morality and religion. . . .“Yet the original inspiration for the Enlightenment was the new physics, which was mechanistic. If nature is entirely governed by mechanistic, causal laws, then it may seem that there is no room for freedom, a soul, or anything but matter in motion. This threatened the traditional view that morality requires freedom. . . . [and] the traditional religious belief in a soul that can survive death or be resurrected in an afterlife. So modern science, the pride of the Enlightenment, the source of its optimism about the powers of human reason, threatened to undermine traditional moral and religious beliefs that free rational thought was expected to support. This was the main intellectual crisis of the Enlightenment.” 
The Critique of Pure Reason
Now, Kant isolated himself for literally years, resisting friendly efforts to bring him out. When he emerged at last, in 1781, he had completed the Critique of Pure Reason. It was his response to the skeptical crisis, replying to Hume’s radical empiricism with the claim that at least some knowledge exists in the mind—inherently, independent of any experience. It launched Kant on a lifetime of explaining and elaborating this thesis into a systematic philosophy of metaphysics, epistemology, ethics, politics, and aesthetics.  
Yet, that did not follow automatically or easily. Readers of the first edition of a work now asserted to be one of the greatest in the history of philosophy expressed disappointment. The book ran to more than 800 pages in the original German, all in a dense, convoluted prose style. Notable philosophers, including Kant’s former students, rejected its claims. Kant had been much praised for earlier works but not for the Critique. Something had to be done.
Kant tried. In 1783, he published the Prolegomena to Any Future Metaphysics, summarizing his views. But it was a friend and colleague, Johann Friedrich Schultz, a professor of mathematics, who began to turn things around with his “Explanations of Professor Kant’s Critique of Pure Reason” (Königsberg 1784), setting forth both briefly and accurately a summary of Kant’s book. 
Things began to turn around so that, in the later 1780s, Kant’s reputation was growing, stimulated by important new works such as his 1784 essay “An Answer to the Question: What Is Enlightenment?” Groundwork of the Metaphysics of Morals in 1785, and in 1786, Metaphysical Foundations of Natural Science. 
Reputation evolved into fame quite unexpectedly with a series of public letters by Karl Leonhard Reinhold, who cast Kant’s ideas as a response to the dominating intellectual issue of the time, the pantheism controversy. It had embroiled some of Germany’s intellectual leaders such as the central figure in the “Jewish Enlightenment” (the Haskalah), Moses Mendelssohn (1729–1786). Reinhold’s letters maintaining that Kant’s philosophy had the answer to the dispute were widely read, spreading Kant’s fame. (Kant later supported Mendelssohn’s influential campaign to reduce prejudice against German Jews.)


Walter Donway

This is Part 1 of two parts. Part 2 gets more critical, asking if Kant "solved" in the Enlightenment crisis--or was the climax of that crisis. Followed by the counter-Enlightenment, with philosophical trends that led both to Marxism and National Socialism--and to the Postmodernism of our day. Stay tuned.