Immanuel Kant

Immanuel Kant (born Emanuel Kant; 22 April 1724 – 12 February 1804) was a German philosopher from Königsberg in the Kingdom of Prussia, regarded as a key figure of the Enlightenment. His systematic work across epistemology, metaphysics, logic, ethics, aesthetics, political theory, and philosophy of religion has made him a major and widely debated influence in modern Western philosophy.

Kant’s philosophy focuses on the human subject, aiming to safeguard knowledge and morality against skepticism and determinism. In the *Critique of Pure Reason* (1781/1787), he proposed transcendental idealism: space and time are not features of the world itself but forms of intuition that structure all experience, so we only know appearances, not things in themselves. He compared this to the Copernican Revolution, suggesting that objects of experience conform to our spatial and temporal intuition and mental categories, rather than the mind conforming to objects.

Kant held that reason is the source of morality, expressed through the categorical imperative binding all rational agents. He saw aesthetics as arising from a disinterested judgment. He believed perpetual peace could be achieved through an international federation of republican states and cooperation. He thought true religion is based on morality, though his exact religious views are disputed.

Kant was born on 22 April 1724 into a Lutheran Prussian German family in Königsberg, East Prussia (now Kaliningrad, Russia). His mother, Anna Regina Reuter, was born in Königsberg to a father from Nuremberg; her surname is sometimes mistakenly given as Porter. His father, Johann Georg Kant, was a harness-maker from Memel (now Klaipėda, Lithuania). Kant thought his family was of Scottish descent, but this is unconfirmed.

Baptized Emanuel, he changed the spelling to Immanuel after learning Hebrew. He was the fourth of nine children, six of whom reached adulthood. The household stressed Pietist values: religious devotion, humility, and literal Bible interpretation. His early education was strict and punitive, focusing on Latin and religious instruction over math and science.

Later in life, Kant kept a highly ordered routine; neighbors supposedly set their watches by his daily walks. He considered marriage twice—once to a widow, once to a Westphalian woman—but waited too long both times. Though never married, he had a rich social life, was a popular teacher, and a modestly successful author even before his major works.

Kant showed early academic promise. He attended the Collegium Fridericianum (directed by Franz Albert Schultz), graduating in summer 1740. At 16, he enrolled at the University of Königsberg, where he spent his entire career. He studied Leibniz and Wolff under Martin Knutzen, a rationalist familiar with British philosophy and science who introduced Kant to Newton’s physics. Knutzen discouraged Kant from pre-established harmony (calling it a “pillow for the lazy mind”) and from idealism, which most 18th-century philosophers rejected. Kant’s later transcendental idealism partly opposed traditional idealism. He had contacts with students, colleagues, and friends who frequented the local Masonic lodge; his main publisher, Johann Friedrich Hartknoch, was also a Freemason.

His father’s stroke and death in 1746 interrupted his studies. Kant left Königsberg shortly after August 1748, returning in August 1754. He worked as a private tutor near Königsberg while continuing research. In 1749, he published his first philosophical work, *Thoughts on the True Estimation of Living Forces* (written 1745–1747).

During the Russian occupation of Königsberg in the Seven Years’ War (1758–1762), Kant’s finances improved through well-paid tutoring for Russian officers and administrators. In December 1758, after Johann David Kypke’s death, he petitioned Empress Elizabeth for the vacant chair of logic and metaphysics at the university, but another candidate got the position.

Kant is best known for ethics and metaphysics but contributed to other fields. In 1754, addressing a Berlin Academy prize question on Earth’s rotation, he argued that the Moon’s gravity would slow Earth’s spin and eventually cause tidal locking. The next year, he extended this reasoning to the Solar System’s formation in *Universal Natural History and Theory of the Heavens*. In 1755, he received a license to lecture at the University of Königsberg and began teaching topics including mathematics.