Immanuel Kant (1724-1804)

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Kant, Immanuel (1724-1804), German philosopher, considered by many the most influential thinker of modern times.


Born in Königsberg (now Kaliningrad, Russia), April 22, 1724, Kant received his education at the Collegium Fredericianum and the University of Königsberg. At the college he studied chiefly the classics, and at the university he studied physics and mathematics. After his father died, he was compelled to halt his university career and earn his living as a private tutor. In 1755, aided by a friend, he resumed his studies and obtained his doctorate. Thereafter, for 15 years he taught at the university, lecturing first on science and mathematics, but gradually enlarging his field of concentration to cover almost all branches of philosophy. Although Kant's lectures and works written during this period established his reputation as an original philosopher, he did not receive a chair at the university until 1770, when he was made professor of logic and metaphysics. For the next 27 years he continued to teach and attracted large numbers of students to Königsberg. Kant's unorthodox religious teachings, which were based on rationalism rather than revelation, brought him into conflict with the government of Prussia, and in 1792 he was forbidden by Frederick William II, king of Prussia, to teach or write on religious subjects. Kant obeyed this order for five years until the death of the king and then felt released from his obligation. In 1798, the year following his retirement from the university, he published a summary of his religious views. He died February 12, 1804.

Kant's Philosophy

The keystone of Kant's philosophy, sometimes called critical philosophy, is contained in his Critique of Pure Reason (1781), in which he examined the bases of human knowledge and created an individual epistemology. Like earlier philosophers, Kant differentiated modes of thinking into analytic and synthetic propositions. An analytic proposition is one in which the predicate is contained in the subject, as in the statement “Black houses are houses.” The truth of this type of proposition is evident, because to state the reverse would be to make the proposition self-contradictory. Such propositions are called analytic because truth is discovered by the analysis of the concept itself. Synthetic propositions, on the other hand, are those that cannot be arrived at by pure analysis, as in the statement “The house is black.” All the common propositions that result from experience of the world are synthetic.

Propositions, according to Kant, can also be divided into two other types: empirical and a priori. Empirical propositions depend entirely on sense perception, but a priori propositions have a fundamental validity and are not based on such perception. The difference between these two types of proposition may be illustrated by the empirical “The house is black” and the a priori “Two plus two makes four.” Kant's thesis in the Critique is that it is possible to make synthetic a priori judgments. This philosophical position is usually known as transcendentalism. In describing how this type of judgment is possible Kant regarded the objects of the material world as fundamentally unknowable; from the point of view of reason, they serve merely as the raw material from which sensations are formed. Objects of themselves have no existence, and space and time exist only as part of the mind, as “intuitions” by which perceptions are measured and judged.

In addition to these intuitions, Kant stated that a number of a priori concepts, which he called categories, also exist. He divided the categories into four groups: those concerning quantity, which are unity, plurality, and totality; those concerning quality, which are reality, negation, and limitation; those concerning relation, which are substance-and-accident, cause-and-effect, and reciprocity; and those concerning modality, which are possibility, existence, and necessity. The intuitions and the categories can be applied to make judgments about experiences and perceptions, but cannot, according to Kant, be applied to abstract ideas such as freedom and existence without leading to inconsistencies in the form of pairs of contradictory propositions, or “antinomies,” in which both members of each pair can be proved true.

In the Metaphysics of Ethics (1797) Kant described his ethical system, which is based on a belief that the reason is the final authority for morality. Actions of any sort, he believed, must be undertaken from a sense of duty dictated by reason, and no action performed for expediency or solely in obedience to law or custom can be regarded as moral. Kant described two types of commands given by reason: the hypothetical imperative, which dictates a given course of action to reach a specific end; and the categorical imperative, which dictates a course of action that must be followed because of its rightness and necessity. The categorical imperative is the basis of morality and was stated by Kant in these words: “Act as if the maxim of your action were to become through your will a general natural law.”

Kant's ethical ideas are a logical outcome of his belief in the fundamental freedom of the individual as stated in his Critique of Practical Reason (1788). This freedom he did not regard as the lawless freedom of anarchy, but rather as the freedom of self-government, the freedom to obey consciously the laws of the universe as revealed by reason. He believed that the welfare of each individual should properly be regarded as an end in itself and that the world was progressing toward an ideal society in which reason would “bind every law giver to make his laws in such a way that they could have sprung from the united will of an entire people, and to regard every subject, in so far as he wishes to be a citizen, on the basis of whether he has conformed to that will.” In his treatise Perpetual Peace (1795) Kant advocated the establishment of a world federation of republican states.

Kant had a greater influence than any other philosopher of modern times. Kantian philosophy, particularly as developed by the German philosopher G.W.F. Hegel, was the basis on which the structure of Marxism was built; the dialectical method, used by both Hegel and Karl Marx, was an outgrowth of the method of reasoning by “antinomies” that Kant used. The German philosopher Johann Fichte, Kant's pupil, rejected his teacher's division of the world into objective and subjective parts and developed an idealistic philosophy that also had great influence on 19th-century socialists. One of Kant's successors at the University of Königsberg, J.F. Herbart, incorporated some of Kant's ideas in his system of pedagogy.

Other Works

In addition to works on philosophy, Kant wrote a number of treatises on various scientific subjects, many in the field of physical geography. His most important scientific work was General Natural History and Theory of the Heavens (1755), in which he advanced the hypothesis of the formation of the universe from a spinning nebula, a hypothesis that later was developed independently by Pierre de Laplace. Among Kant's other writings are Prolegomena to Any Future Metaphysics (1783), Metaphysical Rudiments of Natural Philosophy (1786), Critique of Judgment (1790), and Religion Within the Boundaries of Pure Reason (1793).

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