Immanuel Kant (1724–1804), who was born in a deeply pietistic Lutheran family in Konigsberg, Germany, lived in that town his entire life. At sixteen he entered the University of Konigsberg, where he studied under the tutelage of Martin Knutzen, and read works of Leibniz and Leibniz scholar Christian Wolff. After graduation he worked as a tutor, but in 1755 he was offered an unsalaried lectureship at his alma mater, receiving his fees directly from his students. He served in this capacity until 1770 when he was promoted to the chair of logic and metaphysics at the University of Konigsberg. In his inaugural address he spoke of his goal of restructuring philosophy, resolving the debate between the rationalists (e.g., Descartes, Spinoza, Leibniz, and Wolff) and the empiricists (e.g., Newton, Bacon, Locke, and Hume). For the next ten years he worked on his magnus opus, The Critique of Pure Reason (1781), which accomplished that goal, a Copernican revolution of the theory of knowledge. In 1783 he wrote a shorter Prolegomena to Any Future Metaphysics “for the benefit of teachers,” and in 1785 he wrote his first major work in ethics, Foundation for the Metaphysic of Morals. A successor to that work appeared in 1788, Critique of Practical Reason, and in 1793 he published his theory of rational religion, Religion Within the Limits of Reason Alone.
Kant was an outstanding lecturer and excellent conversationalist, who was known for his generosity and friendliness. He lived a quiet, duty-bound, methodical life, so regular that citizens were said to have set their clocks by his walks. He would leave his home at precisely 4:30 in the afternoon and walk up and down the street on which he lived exactly eight times.
In his own lifetime Kant was recognized as one of the premier philosophers in the Western tradition. Although he wrote on virtually every philosophical topic, he made his major contributions in epistemology and ethics, represented in the selections that follow. Let us briefly examine his thought in these areas.
Building on a mathematical model, the rationalists from Plato through Descartes to Spinoza and Leibniz argued that reason alone is the ultimate source of knowledge, that we have innate or a priori knowledge of ultimate truth which can be accessed by introspection or pure reason. On the other hand, the British empiricists Locke and Hume set forth cogent criticisms against the rationalist projects and argued that experience is the only source of knowledge. The phenomenal success of Newton (1642–1727) in physics seemed to shift the balance of evidence to the empiricists. Empirical Science, not rationalist speculation, offered the best hope of attaining knowledge of the universe.