Leibniz, Gottfried Wilhelm

(1646–1716)

German philosopher, mathematician, and polymath. Leibniz was born in Leipzig, where he attended university from the age of fifteen, and submitted a thesis for the degree of doctor of law at the age of twenty. In 1667 he entered the service of the Elector of Mainz, where he remained until 1672, engaged largely in political writing. He travelled to Paris in 1672, partly to try to persuade Louis XIV to expel the Turks from Egypt (thereby diverting his attention from Germany; the plan did not succeed). He visited England in 1673, and again in 1676, at which time he had completed his discovery of the differential calculus. In this year he travelled to Amsterdam and met Spinoza, and became librarian to the Duke of Brunswick at Hanover, a post he held until his death. Between 1680 and 1697 he was working on his own system of philosophy. Leibniz was the greatest polymath of modern philosophers, making contributions to mathematics, jurisprudence, and history, as well as philosophy. He corresponded extensively with all the major learned men of the time, and was the founder of the Academy of Berlin.

Leibniz's mature philosophical system is both intricate and strange, resting on a small number of highly general principles. The foundation of his thought is the conviction that to each individual there corresponds a complete notion, knowable only to God, from which is deducible all the properties possessed by the individual at each moment in its history. It is contingent that God actualizes the individual that meets such a concept, but his doing so is explicable by the principle of sufficient reason, whereby God had to actualize just that possibility in order for this to be the best of all possible worlds (the thesis subsequently lampooned by Voltaire in Candide ). This deducibility of each of an individual's properties from its complete concept is due to there being an ontological correlate of the complete concept, or in other words a modification of the substance of an individual corresponding to each truth about it. In turn this connects with Leibniz's belief that relations, including causal relations between separate individuals, are only phenomena bene fundata, or constructions that the mind places upon what are at bottom monadic, non-relational facts. However, Leibniz was entirely hostile to 17th-century atomism, so that eventually the individuals of his mature system are the monads : non-physical individual unities, each ‘windowless’, or independent of other things, and each evolving in a way that is entirely dependent upon their intrinsic natures, but each capable of perceptions that in turn ‘express’ the nature of external reality. It is arguable that at this point Leibniz reverts to an Aristotelian conception of nature as essentially striving to actualize its potential. Naturally it is not easy in such a system to make room for space (which Leibniz considered to be relational), corporeal substance, matter (which again he thought of as a phenomenon bene fundatum ), or free will. Along with those of Descartes and Spinoza, Leibniz's is the third of the great rationalist systems of the 17th century, and in many respects the most unusual. Leibniz's major works, none of which contains a finally developed account of his system, are Discourse of Metaphysics (1685); The New System (1695); Theodicy (1710); and Monadology (c. 1713). His correspondence with Arnauld, Jean Bernoulli, Burcher de Volder, Bartholemew des Bosses, and Clarke have been published in separate volumes, as has his controversy with Bayle, and the Nouveaux Essais which contain his reaction to Locke's Essay .