Immanuel Kant

Early Life and Education

Immanuel Kant was born on April 22, 1724, in Königsberg, East Prussia (now Kaliningrad, Russia), the fourth of nine children in a family of modest means. His father was a harness maker; his mother, Anna Regina Reuter, was a devout Pietist whose moral seriousness profoundly shaped Kant's character. He studied at the Collegium Fridericianum, a Pietist school, and entered the University of Königsberg in 1740, studying philosophy, mathematics, and physics.

Kant never left Königsberg and its environs in his entire life — yet from this provincial city he reshaped the intellectual landscape of the modern world.

The Pre-Critical Period

After his father's death in 1746, Kant spent nine years as a private tutor before returning to the university. He earned his doctorate and habilitation in 1755 and became a Privatdozent (unsalaried lecturer) — a position he held for fifteen years before finally being appointed Professor of Logic and Metaphysics in 1770.

During this 'pre-critical' period, Kant published important works in natural philosophy and metaphysics, including the Universal Natural History and Theory of the Heavens (1755), which proposed a nebular hypothesis for the formation of the solar system — remarkably anticipating the Kant-Laplace hypothesis.

The Critical Turn

Kant later described how reading David Hume 'awakened me from my dogmatic slumber.' Hume's demonstration that causation cannot be rationally justified — that our belief in necessary connections between events rests on habit rather than reason — posed a devastating challenge to rationalist metaphysics. Kant spent over a decade working out his response.

The result was the Critique of Pure Reason (Kritik der reinen Vernunft, first edition 1781, substantially revised second edition 1787) — one of the most difficult and most important books ever written. Kant's 'Copernican revolution' proposed that rather than the mind passively conforming to objects, objects conform to the structures of the mind. Space, time, and the categories of the understanding (causation, substance, etc.) are not features of things-in-themselves but the a priori conditions the mind imposes on experience. We can have knowledge only of phenomena (things as they appear to us), never of noumena (things as they are in themselves).

This 'transcendental idealism' simultaneously saved natural science (by grounding causal laws in the necessary structures of the mind) and limited metaphysics (by showing that God, freedom, and immortality lie beyond the reach of theoretical reason).

The Moral Philosophy

Kant's moral philosophy, developed in the Groundwork of the Metaphysics of Morals (1785) and the Critique of Practical Reason (1788), is among the most influential ethical theories ever proposed. Morality, Kant argued, is grounded not in consequences, feelings, or divine command, but in the rational will's capacity to legislate universal law for itself. The supreme principle of morality is the categorical imperative: 'Act only according to that maxim through which you can at the same time will that it become a universal law.'

A second formulation — 'Act so that you treat humanity, whether in your own person or in that of any other, always as an end and never merely as a means' — grounds the unconditional dignity and worth of every rational being.

The Third Critique and Later Works

The Critique of the Power of Judgment (1790) addressed aesthetics and teleology, arguing that judgments of beauty and sublimity involve a distinctive form of reflective judgment, and that we are justified in viewing nature as if it were purposively organized — even though we cannot prove that it is.

Kant's later political and historical writings — Perpetual Peace (1795), The Metaphysics of Morals (1797), and various essays on history, enlightenment, and cosmopolitanism — developed his vision of a rational, law-governed international order.

Death and Legacy

Kant's health declined in his final years, and he died on February 12, 1804, in Königsberg. His last words were reportedly 'Es ist gut' ('It is good').

Kant's influence on philosophy is unparalleled in the modern period. German Idealism (Fichte, Schelling, Hegel), neo-Kantianism, phenomenology, analytic philosophy, and contemporary moral and political theory all trace their roots to Kant's critical philosophy. The categories through which we think about knowledge, morality, aesthetics, and politics remain fundamentally Kantian.