Immanuel Kant: “The Last Enlightenment Philosopher”?

Even to summarize the works that flowed from Kant’s pen can be challenging. They included another classic, the Critique of Practical Reason; major volumes on the nature of morality, aesthetics, politics, and anthropology; and one of the first works on a universal civilization and, in particular, a unified Europe at “perpetual peace.” 

Turning to Kant’s essential conclusions, ideas affirmed by the entire body of work after all intermediate steps and changes, we have an advantage his contemporaries did not enjoy. Centuries of scholarship and a library of books have weighed, debated, and interpreted all that Kant wrote to identify its essentials.

Kant’s arguments and the philosophical system that integrates his conclusions are complex even in outline. But we can begin with “the bottom line” philosophical positions. These encompass three broad categories: (1) human knowledge and the possibility of certainty; (2) morality and its relationship to our reason and free will; (3) implications for other areas, such as aesthetics and politics.1. Knowing and Certainty

Kant says that, contrary to Hume, we can have genuine knowledge of the laws of science because those laws are “contributed” by our minds. The “sensible world,” the world experienced as sensations and perceptions, necessarily conforms to fundamental laws, which we can know, because our minds themselves use those laws to structure what we experience. We can understand substance, space, and time because we supply those forms, or “categories,” ourselves in experiencing our sensations and perceptions. We can, for example, be certain that every effect has a cause, because our minds supply to our experience the category of causality. 

We can identify these categories, or “laws,” by reflecting upon what conditions make experience possible; we see that it is categories such as space, time, and causality—because it would be impossible for us to experience a world where, for instance, a given event fails to have a cause. And this is true not just of our experience but any possible human experience. Kant calls this “immanent metaphysics” because it deals with the conditions built into how we experience.

But, says Kant, if what we know with certainty in our experience (Kant says “a priori,” meaning certainty inherent in our minds not based on experience) is only what we ourselves have put into that experience (the structure, the laws), then we cannot have certain knowledge of things and their nature that are entirely independent of the human mind, which Kant calls things in themselves. Thus, says Kant, “there emerges a very strange result”: Our cognition never reaches beyond appearances, leaving the “thing in itself” unknown.

If scientific knowledge is restricted to the realm of appearances, then it is impossible to have such knowledge of things in themselves that transcend human experience: God, human freedom, morality, and immortality. These are in the realm of “transcendent metaphysics.”

Rejecting knowledge of things in themselves is Kant’s key to reconciling science with morality and religion. God, human freedom, and immortality have a strictly moral basis; still, it would be unjustifiable to believe in them on a moral basis if there existed the possibility of knowing that they were false. But we can’t know anything about things in themselves. By restricting knowledge to appearances and assigning God and the soul to the unknowable realm of “things in themselves,” we are guaranteed to be unable to disprove claims about them. We have put God, the soul, free will, and immortality beyond the reach of reason and logic, so we can justify believing in them on moral grounds. 

Another major payoff, here. The determinism seemingly implied by modern mechanistic science no longer threatens belief in free will, which is required for the validity of morality. Because, of course, science applies only to appearances not things in themselves, the realm of self or soul and their freedom. To repeat: We cannot “know” in the scientific, rational sense that we are free because we cannot know things in themselves. But there are strong moral grounds for affirming human freedom and thus other beliefs rooted in morality. And so we have yet another metaphysics, the “metaphysics of morals.”

It is all summed up neatly in one of Kant’s most famous statements: “I had to deny knowledge in order to make room for faith.”

We know that we have a world where what we can know are appearances and what is real (things in themselves) science cannot know; and we know that we can accept this world with confidence because (as we shall see) we have a priori intuition of the true laws of morality. Does this sound like a triumphant climax of the Enlightenment? The solution to the Enlightenment’s “crisis”?

If the Critique of Pure Reason is the Kantian bible on knowing and certainty, the Metaphysics of Morals (1797) is the bible on moral law.

Kant’s philosophical positions on morality, and the arguments he uses to advance them, are not quite as extended and complex as his reasoning on knowledge and certainty. But this lack of complexity is only relative. Again, we will begin with “the bottom line”—the essential positions—and then suggest the thrust of Kant’s arguments for them.

We no longer are dealing with “appearances” versus things in themselves. Because moral law is discovered entirely within us—not from outside of us in nature, not from God. And what is within us we can grasp as “analytically true” (like the categories we use to structure sensible experience)—true on inspection, undeniable, not susceptible of “proof,” and not requiring it because it is inherently and independently true. If the ardently pietistic faith that was young Kant’s legacy drove him to face down Hume and other Enlightenment skeptics of God, immortality, human freedom, and morality, he had found—at least in his view—unassailable grounds.

The sole source of the good is goodwill itself—only that. A good will acts exclusively from duty in accordance with moral law, which is universal and which the autonomous human person freely gives himself. By this law, we are obligated to treat humanity, which is characterized by rational agency—agency represented in ourselves and others—as an end in itself rather than merely as a means to any ends that any given individual might hold.

This brings us to Kant’s famous “categorical imperative”: “Act only in accordance with that maxim through which you at the same time can will that it become a universal law.” This is a universal moral law derived from the concept of duty, a radical rejection of self-interest. The moral law does not rest upon contingent facts about the world (which we cannot know); it is, Kant maintains, the principle of reason itself. We are happy to act on moral law, and our actions have no other motive than to make ourselves worthy of happiness. 

Thus, for example, if we strive to live a long life because we enjoy living, our choices and actions have no moral significance. They are mere self-interest. If, however, we are ill and afflicted with intolerable pain, from which we see no relief or escape but death, but we nevertheless continue to support our life, we have acted according to moral law, we have done our duty and not acted in our own self-interest. 

If a shopkeeper who follows a policy of honest dealings, including with the vulnerable such as children, because it is good for his business, his action has no moral worth. It is merely prudent, self-interested. On the other hand, if he loses profits by this policy, but still adheres to it, he has acted from duty in obedience to the moral law.

In summary:

A categorical imperative binds us regardless of our desires (selfish interests).

Kant took on one branch of philosophy after another all his life. Here, in capsule form, are his conclusions in politics and aesthetics.

In his major, mature work on political philosophy, Doctrine of Right (1797), he laid out duties under law, which, he wrote, are “concerned only with protecting the external freedom of individuals” and, as appropriate within his theory of morality, indifferent to any individual, private incentives. Echoing the categorical imperative, the basic political principle is that each person is rightfully his own master as far as it is consistent with the entitlement of others to do the same. Kant advocated republican government and a new international organization to achieve unity and “perpetual peace.” In this sense, his political philosophy is essentially a legal doctrine.

In Observations on the Feeling of the Beautiful and Sublime (1764) and the Critique of the Power of Judgment (1790), Kant became among the first philosophers to fully develop aesthetic theory within an integrated philosophical system. For Kant, aesthetic qualities and experiences are subjective—as they must be as part of our sensory experience. If that is true, then what is the logical status of judgments of “taste” (he eventually abandoned the term “aesthetics”)? Unlike moral judgments, judgments of taste can never be directed by a priori laws.

Beauty is not in the artwork or natural phenomena that we call “beautiful”; beauty is our consciousness of pleasure in the “free play” of our minds on something we experience. We may seem to ourselves and others to be using reason to judge what is beautiful, but we are not. Our judgment is not cognitive, not logical, but “aesthetical." Judgments of taste do, however, share this with moral judgments: To claim that a judgment of taste has general validity, it must be disinterested.

As noted, Kant created and promulgated his monumental system at a time of reckoning for the Age of Enlightenment. By the time Kant began his major work, the Enlightenment had been steadily increasing in power, scope, and influence for a century. It had won its struggle against the monopolistic theological consensus in philosophy, education, and common thinking of Scholasticism, by which religion had dominated Europe for centuries. It had launched the Industrial Revolution and radical political revolutions, first in America, then France.

The great debates about knowledge, morality, religion, politics, and economics—to name just a few—had been pushed to their limit by thinkers such as Hume and Rousseau. And, above all, the Enlightenment had built up a huge excitement, expectation, and confidence about the French Revolution—and seen all its hopes crushed and worse (much worse) in the Terror and the world war launched against Europe by Napoleon Bonaparte. Powerful, eloquent, and highly influential critics of the Enlightenment such as Edmund Burke had come on the scene to damn Enlightenment ideas for this catastrophe. Kant came on the European scene during a crisis, recognized it, and responded to it. Could he have become the great champion of Enlightenment ideas and ideals? Its savior at this pivotal moment? We can never know, now.

We do know that he is described as the last of the great Enlightenment philosophers. But we also know that philosophers who followed him did not carry forward the Enlightenment. The intellectual age that ensued is called Romanticism, or the Romantic Rebellion, which indeed turned many Enlightenment themes and ideals on their heads. True, the first half of the nineteenth century saw the genuine and original “liberals” like John Stuart Mill and Jeremy Bentham carry forward the Enlightenment ideas of political freedom and the free-market economics of Adam Smith.

But the full-fledged philosophers were “post-Kantian” German “Idealists” (after Kant’s “Transcendental Idealism”). Johann Gottlieb Fichte, Friedrich Schelling, Georg Wilhelm Friedrich Hegel, and Arthur Schopenhauer were influential. Later, came Friedrich Nietzsche, Edmund Husserl, and Karl Marx. In America, Charles Sanders Pierce ushered in the school of Pragmatism. Much later, came (to mention a few examples) Existentialism, Phenomenalism, Linguistic Analysis, and, as a broad generality, the philosophical/cultural movement Postmodernism. Philosophy professor Stephen Hicks offers a succinct analysis of Kant as an early progenitor of Postmodernism. 

The Age of Enlightenment, to say the very least, had passed as an active, dominant philosophical movement. The genealogy of all these succeeding philosophers and schools is regularly traced to the philosophical system and fundamental concepts of Kant.

We have reviewed, in outline, the “bottom line” philosophical outcomes of Kant’s work. Did they uphold and advance the Enlightenment in its critical hour?

It is not a mystery, then, that Kant was the “last” major “Enlightenment philosopher.” He had dealt with every defining idea and debate of the Enlightenment and produced its opposite—always, however, in the name of “reason,” “pure reason.”

Professor Hicks states the essence of this attack on reason: “Kant [unlike Hume] does not merely raise problems for this or that particular cognitive operation; he argues that, on principle, any kind of cognitive operation, because it operates a certain way, must necessarily not yield results that are about reality. And so, our cognitive operations are by their very natures precluded from putting us in contact with reality. . . . Kant is original in the universality and fundamentality of his skepticism. Cognition is ruled out on principle as a means of knowing reality.”

Philosophers who followed, down to our day, broadly speaking have been anti-Enlightenment. Increasingly so, with time. That means, because the Enlightenment was the “birth of the modern,” these philosophers argued themselves—premise by premise, decade by decade—into increasing opposition to the fundamentals of modernism: reason, individualism, self-interest and individual happiness, capitalism, limited constitutional government, and now, in the environmental movement, a Rousseau-like opposition to the Industrial Revolution.

It is no surprise. It is all in Kant.

At least one contemporary German scholar, Heinrich Heine (1797–1856), assessing Kant’s work, did not restrain his bitterness. Noting the magnitude of Kant’s “destructive, world-crushing thoughts,” he compared him with an “executioner” like Maximilien Robespierre. Taken literally, this reference to Kant is unfair. Kant as far as we know was gentle, sociable, and helpful to his fellow man. It is a philosophical judgment, though not without evidence, to link Kant to Karl Marx, the German philosophical father of the communist revolution, and to German philosophers whose ideas shaped Hitler. Just as it was a speculative insinuation against Kant to comment, at the time of the trial of Nazi war criminal Adolf Eichmann, that Eichmann’s invariable first explanation of his behavior was that he was doing his duty.

It is astonishing the work Kant managed to produce given lifelong poor health, which greatly worsened toward the end. He died in Königsberg in February 1804. He is reported to have uttered “Es ist gut” as he faded and died. It is not clear to what he was referring with “It is good.”

Kant’s tomb and neo-Gothic chapel (mausoleum), now in Kaliningrad, of course, adjoined the northeast corner of the Königsberg Cathedral. Typically, of a Soviet city, over the years the cathedral fell into disrepair and was razed. The tomb and its mausoleum remain, among the few tokens of German times preserved by the Soviets after the Red Army captured the city in 1946.

With the German population expelled, the University of Königsberg was taken over and replaced by Kaliningrad State University. In 2005, it was renamed Immanuel Kant State University of Russia at a ceremony attended by President Vladimir Putin and Chancellor Gerhard Schröder of Germany. It again was renamed after 2010 and for now is Immanuel Kant Baltic Federal University. Presumably, the University “in itself” remains whatever is behind the ever-shifting appearances. But that, of course, we cannot know.