Leibniz, Gottfried Wilhelm 1646-1716
German philosopher and mathematician

Leibniz was born in Leipzig, the son of a professor of moral philosophy. In 1667 he obtained a position at the court of the Elector of Mainz on the strength of an essay on legal education. There he codified laws, drafted schemes for the unification of the churches, and studied the work of Ren� Descartes, Isaac Newton, Blaise Pascal, Robert Boyle and others.

In London he came into contact with mathematicians of Newton's circle, causing a dispute later as to whether he or Newton was the inventor of the infinitesimal calculus; both had published systems in the 1680s. The Royal Society formally declared for Newton in 1711, but the matter was never fully settled. In 1676 Leibniz visited Spinoza in The Hague on his way to take up a new, and his last, post as librarian to the Duke of Brunswick at Hanover. Here he continued to elaborate his mathematical and philosophical theories, without publishing them, and maintained a huge learned correspondence.

He also travelled in Austria and Italy in the years 1687-90 to gather materials for a large-scale history of the House of Brunswick, and went in 1700 to persuade Frederick I of Prussia to found the Prussian Academy of Sciences in Berlin, of which he became the first president. He was disliked by George of Hanover and was left behind in 1714 when the Elector moved the court to London to become King of Great Britain (as George I). Leibniz died in Hanover two years later, without real recognition and with almost all his work unpublished. Remarkable for his encyclopedic knowledge and diverse accomplishments outside the fields of philosophy and mathematics, he was perhaps the last universal genius, spanning the whole of contemporary knowledge.

His best-known doctrine is that the world is composed of an infinity of simple, indivisible, immaterial, mutually isolated 'monads' which form a hierarchy, the highest of which is God; the monads do not interact causally but constitute a synchronized harmony with material phenomena. Leibniz is recognized as one of the great rationalist philosophers but he had perhaps his greatest influence (for example, on Bertrand Russell) as a mathematician and a pioneer of modern symbolic logic.

Bibliography: Leibniz made original contributions to optics, mechanics, statistics, logic and probability theory; he conceived the idea of calculating machines, and of a universal language; he wrote on history, law and political theory; and his philosophy was the foundation of 18th-century rationalism. His Essais de th�odic�e sur la Bont� de Dieu, la libert� de l'homme et l'origine du mal (the Theodicy, 1710), was a relatively popular work in theology, expressing his optimism and faith in enlightenment and reason, which Voltaire satirized brilliantly in Candide ('all is for the best in this best of all possible worlds'). The metaphysics and more technical philosophy are to be found in his response to John Locke, the New Essays on Human Understanding (completed in 1704 but not published until 1765), the Discours de M�taphysique (1846), the correspondence with Antoine Arnauld and with Samuel Clarke, and numerous short papers.

Bibliography: Stuart Brown, Leibniz (1984); Nicholas Rescher, Leibniz: An Introduction to his Philosophy (1979); C D Broad and C Lewy, Leibniz: An Introduction (1975).