Immanuel Kant 1724-1804
Considered one of the most important and influential figures in Western philosophy, Kant developed a comprehensive philosophical system in which he analyzed the foundations of metaphysics, ethics, and aesthetics. The most important exposition of his ideas can be found in his Kritik der reinen Vernunft (1781; Critique of Pure Reason), Kritik der praktischen Vernunft (1788; Critique of Practical Reason), and Kritik der Urteilskraft (1790; Critique of Judgment). In the Critique of Pure Reason, Kant decisively altered the development of modern philosophy by insisting on a separation of the "sensible" and "intelligible" worlds, that which can be perceived by the senses and that which can be ascertained only by the intellect. He applied this distinction to the ethical realm in the Critique of Practical Reason, wherein he argued that an individual's moral decisions are based on rational precepts that are independent of experience in the world and therefore display the exercise of free will. In his study of the basis of aesthetic discrimination, the Critique of Judgment, Kant continued this line of thinking, suggesting that nature, like humanity, has an ideal purpose—a moral end that is revealed by the overall "fitness of things." While Kant is best known for these three central works, his writings on history, politics, and religion are also considered vital contributions to the development of Western thought.
Kant was born in Königsberg in East Prussia in 1724. His family belonged to the Pietist branch of the Lutheran church, a sect that placed great emphasis on austerity and virtue. Kant's father, a saddler, was of modest means, but through the influence of a local pastor, Kant acquired an excellent formal education. From 1732 to 1740 Kant studied at the local Gymnasium, a Pietist school offering intensive study in Latin. Thereafter he entered the University of Königsberg, where he studied philosophy, mathematics, and the natural sciences under a young instructor named Martin Knutzen, who first introduced him to the philosophy of Gottfried Wilhelm Leibniz and Christian von Wolff. Kant's father died in 1746, leaving him without income. Kant found employment as a private tutor for the children of distinguished families, which enabled him to acquire the social graces expected of men of letters at that time. During this period, he published an impressive series of papers on natural history, beginning with Gedanken von der wahren Schätzung der lebendigen Kräfte (1746; Thoughts on the True Estimation of Living Forces), a study of kinetic forces. After completion of his degree in 1755, he spent fifteen years as a non-salaried lecturer, his income derived entirely from modest student fees, and he continued to write prolifically on scientific subjects. In 1764 he published Untersuchung über die Deutlichkeit der Grundsätze der natürlichen Theologie und der Moral, a critique of traditional metaphysics as defined by Leibniz, which is considered his most important work of this formative period.
Kant was appointed to the chair of logic and metaphysics at the University of Königsberg in 1770. His inaugural thesis, De mundi sensibilis atque intelligibilis forma et principiis dissertatio (Dissertation on the Form and Principles of the Sensible and Intelligible Worlds), published the same year, is important for its distinction between sense and understanding, a key concept in his philosophical system. Kant published little while he composed his Critique of Pure Reason, which appeared in 1781, initiating the series of extraordinary works that ultimately brought him widespread recognition for his Critical Philosophy. For the next twenty years, Kant's reputation as a leading spokesman of Enlightenment thought increased as he continued to write prolifically on philosophy, religion, and political theory. A treatise on theology, Die Religion innerhalb der Grenzen der blossen Vernunft (1793; Religion within the Limits of Reason Alone), which denied the supernatural elements of Christianity, resulted in a government ban on future writings by Kant on religious subjects. Around 1800, Kant's health, which had always been precarious, began to deteriorate. After relinquishing his university position in November 1801, Kant rarely left his house and experienced increasing difficulty in following his customary work habits. He died in 1804.
Kant's major philosophical principles are contained in the three Critiques. While the first of these works, Critique of Pure Reason, has often been criticized for the density of its style, attributed by scholars to Kant's reliance on the scholastic jargon of Wolff and his followers, the clarity and originality of the philosophical concepts articulated in the treatise are universally acknowledged. In Critique of Pure Reason, Kant systematically analyzed the foundations of human knowledge. The majority of the book is devoted to a "Transcendental Doctrine of Elements," wherein Kant elaborates his epistemology; this is followed by a much shorter "Transcendental Doctrine of Method," which outlines the proper application of "pure reason." The Critique's first part is divided into the "Transcendental Aesthetic," the "Transcendental Analytic," and the "Transcendental Dialectic," which examine the foundations of mathematics, the physical sciences, and metaphysics, respectively. In all three areas Kant sought to determine if it was possible to prove the validity of "a priori synthetic statements," that is, philosophical propositions that are not only true without reference to experience, but which also expand our knowledge. In the process, Kant effected what he called a "Copernican revolution" in philosophy: whereas formerly philosophers had considered the mind a passive agent whose judgments conformed to objects in the world, Kant believed that there were epistemic constraints on what could constitute objects of possible knowledge, and that experience is constituted both by sensible intuitions and concepts.
Like the first Critique, Kant's second major treatise, Critique of Practical Reason, is subdivided into a table of "Elements" and a "Methodology." While theoretical reason is concerned with the basis of experience, practical reason is concerned with the ethical significance of free action. In Critique of Pure Reason, Kant distinguishes between phenomenal and noumenal reality—that which appears to us through the senses and that which lies behind appearances. In the second Critique, he draws a similar distinction. On a purely phenomenal level, Kant explains, individuals are conditioned by the law of causality, which states that every effect has a predetermined cause. Practically speaking, this would destroy the possibility of freedom. Kant also suggests, however, that the individual is aware of himself as a purely rational, intelligible being. As such, an individual's actions may be conditioned by sensuous motives or grounded in the moral law, the "categorical imperative," which requires us to "act only on that maxim through which you can at the same time will that it should become a universal law." Kant also asserts, in concluding his arguments about freedom, that the concepts of God and immortality, while entertained as a mere possibility for theoretical reason, are necessary for practical reason.
In Critique of Judgment, Kant discusses judgments of taste and purposiveness in nature. The work is divided into a "Critique of Aesthetic Judgment" and a "Critique of Teleological Judgment." The first section is devoted to aesthetic judgments of the beautiful, which for Kant are subjective but universally valid. In the contemplation of a beautiful object, Kant explains, the person experiences a free play of the understanding and the imagination. In the second part of Critique of Judgment, Kant rejects the then fashionable mechanistic argument as an explanation for the harmony of parts in organisms, as well as the theological argument that it is the product of an intelligent design. Rather, purposiveness in nature must be adopted as a methodological assumption in any scientific explanation.
Kant's Copernican turn in philosophy marks a revolution in philosophical methodology that spawned a whole generation of followers, critics, and disagreeing interpreters of his thought. Kant greatly influenced Johann Gottlieb Fichte's (1762-1814) idealism, which along with a fuller appreciation of the third Critique fueled German Romanticism, especially Friedrich Schelling (1775-1854) and Johann Christoph Friedrich von Schiller (1759-1805). Later philosophers, such as Arthur Schopenhauer (1788-1860) and Georg Wilhelm Friedrich Hegel (1770-1831), developed particular aspects of Kant's thought in their own philosophies, as did other idealists such as Josiah Royce (1855-1916). While Kant has been criticized for his abstruse style and overuse of technical vocabulary, his philosophical works continue to be intensely scrutinized by scholars throughout the world. In ethics, metaphysics, mathematics, and aesthetics, philosophers since Kant have had to address his thought in developing their own, upholding Kant's legacy as possibly the most influential philosopher of the modern era.