Immanuel Kant

Immanuel Kant, born Emanuel Kant on 22 April 1724, was a German philosopher from Königsberg in the Kingdom of Prussia, in East Prussia. He was born into a Prussian German family of Lutheran faith and later changed the spelling of his name to Immanuel after learning Hebrew. Kant became one of the central thinkers of the Enlightenment, and his work ranged across epistemology, metaphysics, logic, ethics, aesthetics, political theory, and the philosophy of religion.

His early life was marked by discipline and religious seriousness. His father, Johann Georg Kant, was a German harness-maker from Memel, and his mother, Anna Regina Reuter, was born in Königsberg. Kant was the fourth of nine children, six of whom reached adulthood. The household stressed Pietist values: religious devotion, humility, and a literal reading of the Bible. His schooling was strict and punitive, with a strong emphasis on Latin and religious instruction rather than mathematics and science.

Kant showed an early aptitude for study. He attended the Collegium Fridericianum and graduated in 1740, then enrolled at the University of Königsberg at age 16. There he studied the philosophy of Gottfried Leibniz and Christian Wolff under Martin Knutzen, a rationalist who also knew British philosophy and science and introduced Kant to the new mathematical physics of Isaac Newton. Knutzen warned him away from the theory of pre-established harmony and from traditional idealism, influences that helped shape Kant’s later effort to rethink how the mind and experience are related.

His studies were interrupted after his father’s stroke and death in 1746. Kant left Königsberg shortly after August 1748 and returned in August 1754, working in the meantime as a private tutor in towns around the city while continuing his research. In 1749 he published his first philosophical work, Thoughts on the True Estimation of Living Forces. In 1755 he received a license to lecture at the University of Königsberg, teaching mathematics, physics, logic, and metaphysics. He later lectured on geography, natural law, ethics, and anthropology, and after becoming a professor in 1770 he broadened his teaching still further.

Before his major philosophical works, Kant also wrote on natural science. In 1754 he argued that the Moon’s gravity would slow Earth’s spin and that gravity would eventually bring the Moon’s tidal locking into line with Earth’s rotation. In Universal Natural History and Theory of the Heavens in 1755, he proposed the nebular hypothesis for the formation of the Solar System and suggested that distant “nebulae” might be other galaxies. He also wrote on winds and on the 1755 Lisbon earthquake, seeking natural rather than supernatural explanations.

Kant is best known for the philosophy that took full form in Critique of Pure Reason, published in 1781 and revised in 1787. There he argued for transcendental idealism: space and time are forms of intuition that structure all experience, and human knowledge reaches appearances rather than things in themselves. He also held that reason is the source of morality, that the categorical imperative binds all rational agents, that aesthetic judgment is disinterested, and that true religion is grounded in morality. Kant died on 12 February 1804, after a life so orderly that neighbors were said to set their watches by his daily walks. His words continue to draw readers because they press plain but demanding questions: what can we know, what should we do, and how should human beings live together?