Philosophy of the Modern Era

Kant

General Overview of Kant's Philosophy

Immanuel Kant (1724—1804) is widely regarded as the greatest philosopher of the modern era. While I cannot fully endorse this assessment, it would be foolish to overlook his immense significance. Throughout his life, Kant resided primarily in Königsberg or its vicinity in East Prussia. His external life was largely academic, flowing quietly without disruption, even amidst events such as the Seven Years' War (when Russians occupied East Prussia), the French Revolution, and the early career of Napoleon. Raised in the Wolffian interpretation of Leibniz's philosophy, he ultimately repudiated it under the influence of Rousseau and Hume. Hume's critique of causality awakened him from a dogmatic slumber—so he claims—but this awakening proved temporary, as he soon devised a remedy that lulled him back to sleep. For Kant, Hume represented an opponent to be refuted, while Rousseau's influence ran deeper. Kant was a man of such habitual routine that people would set their clocks by the moment he left his door for a walk; however, one day, his schedule was disrupted for several days while he read "Emile." He remarked that he had to read Rousseau's works multiple times, as the charm of his style initially obscured the content. Although he was raised as a Pietist, he held liberal views in both politics and theology. He sympathized with the French Revolution until the Reign of Terror and believed in democracy. As we shall see, his philosophy allowed for appeals to the heart against the cold dictates of theoretical reason, which could, with slight exaggeration, be seen as a pedantic variant of the Savoyard vicar. His principle that each person must be regarded as an end in themselves embodies a form of human rights doctrine, and his love for freedom is manifest in his assertion (regarding children as well as adults): "Nothing can be more dreadful than that a person's actions should be subject to the will of another."

Kant's early works pertain more to science than to philosophy. Following the Lisbon earthquake, he penned a study on the theory of earthquakes. He also wrote a treatise on wind and a brief note on whether the westerly winds in Europe are humid due to their crossing the Atlantic Ocean. Physical geography was a subject that captured his greatest interest.

His most significant scientific work is "Universal Natural History and Theory of the Heavens" (1755), which anticipates Laplace's hypothesis about the origin of the Solar System from nebulae and establishes a possible genesis for the Solar System. Certain sections of this work possess remarkable Miltonian grandeur. It demonstrates an inventive merit that proves the fruitfulness of the hypothesis; however, he does not present serious arguments in its favor as Laplace does. At times, it is purely fantastical, as in the assertion that all planets are inhabited and that the most distant planets have the best inhabitants. This perspective is commendable for its earthly humility, yet it lacks any scientific foundation.

During a period when Kant was particularly troubled by the arguments of skeptics, he wrote a curious work titled "Dreams of a Spirit-Seer, Explained by Dreams of Metaphysics" (1766). The "Spirit-Seer" refers to Swedenborg, whose mystical system was presented to the world in an immense work, four copies of which were sold: three to unknown purchasers and one to Kant. Kant, half-seriously and half-jokingly, claimed that Swedenborg's system, which he termed "fantastic," might be nothing more than orthodox metaphysics. However, it cannot be said that he regarded Swedenborg with complete disdain. Within him lived a mystic, though not particularly evident in his writings, who admired Swedenborg, whom Kant described as "very sublime."

Like everyone else at the time, he wrote a treatise on the sublime and beauty. The night is sublime, the day is beautiful; the sea is sublime, the land is beautiful; the man is sublime, the woman is beautiful, and so forth. The "Encyclopaedia Britannica" notes: "Since he never married, he retained the habits of student youth into old age." I would like to know whether the author of that article was a bachelor or a married man.

Kant's most important book is "Critique of Pure Reason" (1st edition in 1781, 2nd edition in 1787). The aim of this work is to demonstrate that while no knowledge can transcend experience, it nonetheless comprises a priori elements that are not inductively derived from experience. According to Kant, the a priori portion of our knowledge encompasses not only logic but also much that cannot be included within or derived from it. He distinguishes two differentiations that Leibniz conflated. On one side, there is a distinction between "analytic" and "synthetic" judgments; on the other, a distinction between "a priori" and "empirical" judgments. Some comments are warranted regarding each of these distinctions.

An "analytic" judgment is one in which the predicate is contained within the subject. For example, "a tall man is a man" or "an equilateral triangle is a triangle." All such judgments follow from the law of contradiction; to assert that a tall man is not a man would be inherently contradictory. A "synthetic" judgment, conversely, is one that is not analytic. All judgments that we know solely through experience are synthetic. We cannot discover truths such as "Tuesday was a rainy day" or "Napoleon was a great general" merely through the analysis of concepts. However, in contrast to Leibniz and all other philosophers preceding him, Kant does not permit the converse: namely, that all synthetic judgments are known only through experience.

This leads us to the second of the aforementioned distinctions. An "empirical" judgment is one that we can only know through sensory perception, whether our own or through the sensory perceptions of those whose verbal testimony we accept. Historical and geographical facts fall into this category; scientific laws do as well—our knowledge of their truth invariably depends on observational data. "A priori" judgments, on the other hand, are those which, although they may be derived from experience when known, seemingly possess a foundation other than experience. A child studying arithmetic may benefit from perceiving two balls and two others, and, upon observing them together, he perceives four balls. Yet when he grasps the general judgment "2 + 2 = 4," he will require no further confirmation through examples; the judgment possesses a certainty that induction can never provide to a general law. All judgments of pure mathematics are a priori in this sense.

Hume demonstrated that the law of causality is not analytic, concluding that we cannot be certain of its truth. Kant adopted the view that the law of causality is synthetic but nonetheless asserted that it is known a priori. He claimed that arithmetic and geometry are both synthetic and a priori. He thus arrived at the following formulation of his problem: How are synthetic judgments a priori possible?

The answer to this question, along with all its implications, forms the core theme of the "Critique of Pure Reason." Kant's resolution of this problem was met with profound confidence. He spent twelve years developing this issue but only five months composing his lengthy book after his theory took shape. In the preface to the first edition, he states: "I venture to assert that there cannot be a single metaphysical question that has not been resolved here, or for which at least a key has not been provided." In the preface to the second edition, he compares himself to Copernicus, asserting that he has brought about a Copernican revolution in philosophy.

According to Kant, the external world provides only the material of sensation, yet our own spiritual apparatus organizes this material in space and time, delivering concepts through which we comprehend experience. The things-in-themselves, which are the causes of our sensations, remain unknowable; they do not exist in space and time, are not substances, and cannot be described by any of the general concepts that Kant refers to as "categories." Space and time are subjective; they are part of our perceptual apparatus. Thus, we can be assured that whatever we perceive will reveal characteristics that geometry and the science of time examine. If you have always worn blue glasses, you can be certain that you will see everything as blue (this is not a Kantian example). In a similar manner, since you always wear spatial glasses in your mind, you are confident that you see everything in space. Therefore, geometry is a priori in the sense that it must be true of all that is perceived, but we have no grounds to assume that something analogous is true of the things-in-themselves, which we do not perceive.

Kant asserts that space and time are not concepts; rather, they are forms of "intuition." (The German word "Anschauung" literally means "contemplation" or "view." Although "intuition" is the accepted translation, it remains somewhat unsatisfactory.) However, there are also a priori concepts: there are twelve categories, which Kant derives from the forms of syllogism. These twelve categories are divided into four triads: 1) quantity: unity, plurality, universality; 2) quality: reality, negation, limitation; 3) relation: substance and accident, cause and effect, interaction; 4) modality: possibility, existence, necessity. They are subjective in the same sense as space and time, meaning our spiritual constitution is such that they apply to any perception, but there is no reason to believe they apply to things-in-themselves. In relation to causation, however, there is a contradiction, since things-in-themselves are regarded by Kant as the causes of sensations, while free will is seen by him as the cause of phenomena in space and time. This contradiction is not an accidental oversight; it is an essential part of his system.

Much of the "Critique of Pure Reason" is devoted to demonstrating the difficulties that arise from applying space and time or categories to things that are not perceived. When this occurs, Kant asserts, we arrive at "antinomy," meaning mutually contradictory judgments, each of which can be evidently proven. Kant presents four such antinomies, each containing a thesis and an antithesis.

In the first antinomy, the thesis states: "The world has a beginning in time and is also limited in space." The antithesis claims: "The world has no beginning in time and is limitless in space. It is infinite both in time and in space."

The second antinomy proves that every complex substance both consists of and does not consist of simple parts.

The thesis of the third antinomy asserts that there are two kinds of causality: one corresponding to the laws of nature, and the other to freedom. The antithesis states that there is only one causality corresponding to the laws of nature.

The fourth antinomy demonstrates that an absolutely necessary Being both exists and does not exist.

This part of the "Critique" had a profound influence on Hegel, whose dialectic develops entirely through antinomies.

In the widely known section of the book, Kant seeks to refute all purely rational proofs of the existence of God. He clearly shows that he has other grounds for belief in God. These are later articulated in his "Critique of Practical Reason" (1786). For now, his aim is entirely negative.

He states that there are only three proofs of God's existence through pure reason: the ontological proof, the cosmological proof, and the physico-theological proof.

The ontological proof, as he presents it, defines God as ens realissimum, the most real being, that is, the subject of all predicates that belong to being absolutely. It is claimed by those who believe in the validity of the proof that since "existence" is such a predicate, this subject must possess the predicate of "existence," that is, must exist. Kant counters this by arguing that existence is not a predicate. A hundred thalers that I merely imagine can possess all the same predicates as a hundred real thalers.

The cosmological proof asserts that if anything exists, then an absolutely necessary Being must exist; now I know that I exist, therefore, an absolutely necessary Being exists, and it must be ens realissimum. Kant contends that the final step in this proof reverts to the ontological proof, and is thus refuted by what has already been stated.

The physico-theological proof is the customary proof from the contrary, yet clad in metaphysical garb. It claims that the universe exhibits order, which serves as evidence of the existence of purpose. Kant examines this reasoning with great attention but points out that at best, it only proves the existence of a Craftsman, not a Creator, and therefore cannot provide a correct conception of God. He concludes that "the only theology of reason that is possible is one based on the laws of morality or that seeks guarantees within them."

God, freedom, and immortality, he asserts, are three "ideas of reason." However, although pure reason leads us to formulate these ideas, it cannot itself prove their reality. The significance of these ideas is practical, meaning they are related to morality. A purely intellectual application of reason leads to difficulties. The only correct use is directed towards moral ends.

The practical application of reason is briefly addressed at the end of the "Critique of Pure Reason" and more thoroughly in the "Critique of Practical Reason." The argument is that the moral law demands justice, that is, happiness proportional to virtue. Only Providence can ensure this, and it is evident that it does not provide it in this life. Therefore, God and an afterlife must exist, and freedom must exist, for otherwise, virtue cannot be a reality.

Kant's ethical system, as outlined in his "Metaphysics of Morals" (1785), holds significant historical importance. This book contains the "categorical imperative," which, at least as a phrase, is well-known outside the circle of professional philosophers. As one might expect, Kant is not satisfied with utilitarianism or any other doctrine that assigns a purpose to morality beyond itself. He desires, as he states, "a completely isolated metaphysics of morals, which is not mixed with any theology, physics, or metaphysics." All moral concepts, he continues, have their place and origin entirely a priori in reason. Moral worth exists only when a person acts from a sense of duty. It is not enough for an action to be as duty prescribes. A merchant who is honest out of self-interest, or a person who is kind out of compassion, is not virtuous. The essence of morality must be derived from the concept of law, since although everything in nature acts according to laws, only a rational being has the power to act in accordance with the idea of law, that is, with Will. The idea of an objective principle, as it is imposed on the will, is called the command of reason, and the formula of the command is termed the imperative.

There are two types of imperatives: the conditional imperative, which states, "You must do such and such if you wish to achieve this or that goal," and the categorical imperative, which declares that a certain type of action is objectively necessary irrespective of any end. The categorical imperative is synthetic and a priori. Its nature is derived by Kant from the concept of law:

"If I conceive of the categorical imperative, I immediately know what it contains within itself. In fact, since the imperative, apart from the law, contains only the necessity of the maxim to act in accordance with that law, and since the law contains no condition by which it would be limited, nothing remains except the universality of the law in general. The maxim of action must accord with it, and it is precisely this accord that the imperative presents as necessary. Thus, there exists but one categorical imperative, which is as follows: 'Act only according to that maxim whereby you can at the same time will that it should become a universal law, as if the maxim of your action were to become a universal law of nature through your will.'"

Kant provides the following example of action as dictated by the categorical imperative: it is wrong to borrow money with no intention of repaying it, for if we all sought to do so, there would be no money left to borrow. Similarly, it can be shown that theft and murder are condemned by the categorical imperative. However, there are certain actions that Kant would certainly consider erroneous, yet their erroneousness cannot be demonstrated through his principles, such as suicide. It would be entirely possible for a melancholic person to wish for everyone to end their lives. Their maxim seemingly provides a necessary, albeit insufficient, criterion of virtue. To obtain a sufficient criterion, we must reject Kant's purely formal viewpoint and consider the consequences of actions. Kant, however, emphasizes that virtue does not depend on the intended outcome of an action, but solely on the principle from which the action arises. And if this is accepted, then nothing more specific than his maxim can be conceived.

Kant asserts, though it appears that his principle does not entail this consequence, that we ought to act such that each individual is regarded as an end in themselves. This can be seen as an abstract formulation of the doctrine of human rights and, thus, this assertion is susceptible to the same objections. If taken seriously, it would render resolution impossible whenever the interests of two nations conflict. In particular, the difficulties in political philosophy become evident, which demands a certain principle—such as a preference for the majority—whereby the interests of some may, when necessary, be sacrificed for the interests of others. If there is to be any ethical foundation for government, then its aim must be singular; and the only such aim compatible with justice is the welfare of society. However, one might interpret Kant's principle in the sense that not every individual is an absolute end, but that one must regard all individuals equally when determining actions that affect many people. Thus, this interpreted principle can be seen as providing an ethical basis for democracy. In this interpretation, it is not subject to the objections mentioned earlier.

The rigor and vivacity of Kant's mind in his later years are evidenced by his essay "Perpetual Peace" (1795). In this work, he defends a federation of free states united by a treaty prohibiting war. Reason, he asserts, entirely condemns war, which can only be prevented by an international government. The civil constitution of individual states should be "republican," though he attributes to this term the meaning that the executive and legislative powers are separated. He does not imply that there should be no king; in fact, he states that it is most feasible to achieve perfect governance under a monarchy. Influenced by the regime of terror, he viewed democracy with suspicion. He argued that it necessarily leads to despotism, as it establishes executive power. "The so-called 'people as a whole' implements measures not for all, but only for the majority; thus, the general will is in contradiction with itself and with the principle of freedom." This phrase reflects Rousseau's influence, yet the important idea of a global federation as a means of securing peace from war is not derived from Rousseau.

Following 1933, this treatise led to Kant falling into disfavor in his own country.