Kant (1724-1804) was a German philosopher of the late Enlightenment period. He lived his entire live in the town of Königsberg in the part of Germany known at the time as Prussia. Though he never left Königsberg, he became one of the leading intellectual figures of his time and one of the most influential thinkers in the history of Western philosophy through his copious writings and correspondence with other thinkers across Europe.

Two schools of thought about the nature of human knowledge dominated much Enlightenment philosophy: rationalism and empiricism. Rationalists (such as René Descartes and Gottfried Wilhelm Leibniz) tended to believe that all true knowledge comes from the deductive reasoning powers of the human mind, while empiricists (such as John Locke and David Hume) rejected the notion that any ideas are “innate” and insisted that all knowledge comes from experience. Kant was the first philosopher to synthesize these competing schools of thought in what he called “transcendental idealism,” an elaborate philosophical system in which experience and the human mind work together to generate knowledge of a world that conforms to the structure of the mind.

Kant’s work ranges across so many issues—from astronomy to morality and from theology to political philosophy—that one cannot concisely summarize it, but the bulk of his mature work (from the 1780s forward) concerns the power of the human mind to shape the world and to govern itself.