Kant, Immanuel (1724–1804)

German philosopher. He believed that knowledge is not merely an aggregate of sense impressions but is dependent on the conceptual apparatus of the human understanding, which is itself not derived from experience. In ethics, Kant argued that right action cannot be based on feelings or inclinations but conforms to a law given by reason, the categorical imperative.

It was in his Kritik der reinen Vernunft/Critique of Pure Reason (1781) that Kant inaugurated a revolution in philosophy by turning attention to the mind's role in constructing our knowledge of the objective world. He also argued that God's existence could not be proved theoretically.

His other main works are Kritik der praktischen Vernunft/Critique of Practical Reason (1788) and Kritik der Urteilskraft/Critique of Judgement (1790).

Born in Königsberg (in what was then East Prussia), Kant attended the university there, and was its professor of logic and metaphysics 1770–97. His first book was Gedanken von der wahren Schätzung der lebendigen Kräfte/Thoughts on the True Estimates of Living Forces (1747). In Allgemeine Naturgeschichte und Theorie des Himmels/Universal Natural History and Theory of the Heavens (1755), he put forward the idea that the Solar System was part of a system of stars constituting a galaxy and that there were many such galaxies making up the whole universe. Kant believed that planetary bodies in the Solar System had been formed by the condensation of nebulous, diffuse primordial matter; this later became known as the Kant–Laplacian theory (when put forward by French astronomer Pierre Laplace). Kant was also influenced by the theories of English scientist Isaac Newton.

Other works include Prolegomena (1783), Metaphysik der Sitten/Metaphysic of Ethics (1785), and Metaphysische Anfangsgründe der Naturwissenschaft/Metaphysic of Nature (1786).