Immanuel Kant

Immanuel Kant was a German philosopher and one of the central Enlightenment thinkers. Kant's comprehensive and systematic works in epistemology, metaphysics, ethics, and aesthetics have made him one of the most influential figures in modern Western philosophy.

In his doctrine of transcendental idealism, Kant argued that space and time are mere "forms of intuition" which structure all experience, and therefore that while "things-in-themselves" exist and contribute to experience, they are nonetheless distinct from the objects of experience. From this it follows that the objects of experience are mere "appearances", and that the nature of things as they are in themselves is consequently unknowable to us. In an attempt to counter the skepticism he found in the writings of philosopher David Hume, he wrote the Critique of Pure Reason (1781/1787), one of his most well-known works. In it, he developed his theory of experience to answer the question of whether synthetic a priori knowledge is possible, which would in turn make it possible to determine the limits of metaphysical inquiry. Kant drew a parallel to the Copernican revolution in his proposal that the objects of the senses must conform to our spatial and temporal forms of intuition, and that we can consequently have a priori cognition of the objects of the senses.

Kant believed that reason is also the source of morality, and that aesthetics arise from a faculty of disinterested judgment. Kant's views continue to have a major influence on contemporary philosophy, especially the fields of epistemology, ethics, political theory, and post-modern aesthetics. He attempted to explain the relationship between reason and human experience and to move beyond what he believed to be the failures of traditional philosophy and metaphysics. He wanted to put an end to what he saw as an era of futile and speculative theories of human experience, while resisting the skepticism of thinkers such as Hume. He regarded himself as showing the way past the impasse between rationalists and empiricists, and is widely held to have synthesized both traditions in his thought.

Kant was an exponent of the idea that perpetual peace could be secured through universal democracy and international cooperation, and that perhaps this could be the culminating stage of world history. The nature of Kant's religious views continues to be the subject of scholarly dispute, with viewpoints ranging from the impression that he shifted from an early defense of an ontological argument for the existence of God to a principled agnosticism, to more critical treatments epitomized by Schopenhauer, who criticized the imperative form of Kantian ethics as "theological morals" and the "Mosaic Decalogue in disguise", and Nietzsche, who claimed that Kant had "theologian blood" and was merely a sophisticated apologist for traditional Christian faith. Beyond his religious views, Kant has also been criticized for the racism presented in some of his lesser-known papers, such as "On the Use of Teleological Principles in Philosophy" and "On the Different Races of Man". Although he was a proponent of scientific racism for much of his career, Kant's views on race changed significantly in the last decade of his life, and he ultimately rejected racial hierarchies and European colonialism in Perpetual Peace: A Philosophical Sketch (1795), though still considering Europeans as "civilized" to the exception of others. The most serious problems in the consideration of Kant's philosophical legacy came in the late nineteenth century with the advent of modern logic. Logician such as Gottlob Frege, Kurt Gödel, Willard Van Orman Quine and most recently Saul Kripke, came rejected the entire premises of Kant's logic as grounded in metaphysics. William and Martha Kneale have also noted that it was Kant "with his transcendentalism who begun the curious mixture of metaphysics and epistemology which was presented as logic by Hegel and the other philosophers of the nineteenth century" Eventually, also the fundamental pillar of Kant's transcendental idealism, i.e that space and time are pure but subjective a priori conditions of human perception, collapsed with the advent of modern quantum physics and was refuted as "irrational". Albert Einstein once explicitly said that "if one does not want to assert that relativity theory goes against reason, one cannot retain the a priori concepts and norms of Kant’s system".

Kant published other important works on ethics, religion, law, aesthetics, astronomy, and history during his lifetime. These include the Universal Natural History (1755), the Critique of Practical Reason (1788), the Critique of Judgment (1790), Religion within the Bounds of Bare Reason (1793), and the Metaphysics of Morals (1797).

Kant showed a great aptitude for study at an early age. He first attended the Collegium Fridericianum from which he graduated at the end of the summer of 1740. In 1740, aged 16, he enrolled at the University of Königsberg, where he spent his whole career. He studied the philosophy of Gottfried Leibniz and Christian Wolff under Martin Knutzen (Associate Professor of Logic and Metaphysics from 1734 until his death in 1751), a rationalist who was also familiar with developments in British philosophy and science and introduced Kant to the new mathematical physics of Isaac Newton. Knutzen dissuaded Kant from the theory of pre-established harmony, which he regarded as "the pillow for the lazy mind".

Kant is best known for his work in the philosophy of ethics and metaphysics, but he made significant contributions to other disciplines. In 1754, while contemplating on a prize question by the Berlin Academy about the problem of Earth's rotation, he argued that the Moon's gravity would slow down Earth's spin and he also put forth the argument that gravity would eventually cause the Moon's tidal locking to coincide with the Earth's rotation.

Kant's health, long poor, worsened and he died at Königsberg on 12 February 1804, uttering "Es ist gut (It is good)" before expiring. His unfinished final work was published as Opus Postumum. Kant always cut a curious figure in his lifetime for his modest, rigorously scheduled habits, which have been referred to as clocklike. However, Heinrich Heine noted the magnitude of "his destructive, world-crushing thoughts" and considered him a sort of philosophical "executioner", comparing him to Robespierre with the observation that both men "represented in the highest the type of provincial bourgeois. Nature had destined them to weigh coffee and sugar, but Fate determined that they should weigh other things and placed on the scales of the one a king, on the scales of the other a god.