Immanuel Kant

Life and legacy

Immanuel Kant was born on 22 April 1724 in Konigsberg, the capital of East Prussia (now Kaliningrad, Russia), the fourth of nine children in a devout Pietist family. His father, Johann Georg Kant, was a harness-maker; his mother, Anna Regina Reuter, instilled in him a deep moral seriousness that shaped his entire philosophical project. Educated at the University of Konigsberg, Kant worked for nine years as a private tutor before returning to the university, where he spent fifteen years as an unsalaried lecturer before finally being appointed to the chair of logic and metaphysics in 1770.

Kant's intellectual life divides into two periods. During his "pre-critical" years, he worked broadly in natural science and metaphysics, producing an important cosmological hypothesis (the Kant-Laplace nebular theory of the formation of the solar system). Then, awakened from what he called his "dogmatic slumber" by reading David Hume, Kant embarked on the great critical project that would occupy the rest of his career. The result was the Critique of Pure Reason (1781, revised 1787), one of the most important and difficult works in the history of philosophy.

In the Critique of Pure Reason, Kant argued that the human mind does not passively receive experience but actively structures it through innate categories of understanding - such as space, time, and causality. We can know the world as it appears to us (the phenomenal world), but we can never know things as they are in themselves (the noumenal world). This "Copernican revolution" in philosophy resolved the deadlock between rationalism and empiricism by showing that both experience and the mind's own structures contribute to knowledge.

Kant's moral philosophy, set out in the Groundwork of the Metaphysics of Morals (1785) and the Critique of Practical Reason (1788), was equally revolutionary. He argued that moral duty is grounded not in consequences or divine command but in the categorical imperative - the principle that one should act only according to rules that one could will to be universal laws. This framework placed human autonomy and rational dignity at the center of ethics and profoundly influenced subsequent moral and political philosophy.

Kant never traveled more than about fifty miles from Konigsberg, and his daily routine was so regular that neighbors reportedly set their clocks by his afternoon walks. Yet from his provincial study, he produced a body of work that shaped virtually every subsequent branch of philosophy. His essay "Answering the Question: What Is Enlightenment?" (1784) defined the movement's essence with memorable clarity: "Sapere aude! - Have the courage to use your own understanding!" He died in Konigsberg on 12 February 1804, his last words reportedly being "Es ist gut" ("It is good").

Key accomplishments

• Published the Critique of Pure Reason (1781/1787), transforming epistemology and metaphysics
• Formulated the categorical imperative, the foundational principle of deontological ethics
• Defined Enlightenment as "Sapere aude" - the courage to use one's own understanding
• Proposed the Kant-Laplace nebular hypothesis for the formation of the solar system
• Authored three great Critiques (Pure Reason, Practical Reason, Judgment) that reshaped Western philosophy

Quotes

Sapere aude! Have the courage to use your own understanding! - that is the motto of Enlightenment.

Answering the Question: What Is Enlightenment?, 1784

Two things fill the mind with ever new and increasing admiration and awe: the starry heavens above me and the moral law within me.

Critique of Practical Reason, Conclusion, 1788

Related figures