Gottfried Wilhelm Leibniz
German polymath, philosopher and mathematician (1646–1716), born in Leipzig, one of the last truly universal minds in history: he made original contributions to logic, metaphysics, law, theology, linguistics, geology and diplomacy, while serving as librarian and councillor at the court of Hanover, and kept up an epistolary correspondence with hundreds of correspondents across Europe. He independently developed, apart from Newton —with whom he engaged in a bitter priority dispute that poisoned the rest of his life and divided the European scientific community— infinitesimal calculus, and his notation, clearer and more practical than Newton's, is still universally used today. In metaphysics, his crucial work, the Monadology (1714), proposes that ultimate reality is composed of monads, simple, indivisible, windowless substances that do not physically interact with one another but whose internal states God has 'pre-established' in a perfect harmony, causing them to evolve in perfect correspondence, like clocks synchronised from the outset without any need for direct causal contact. In the Theodicy (1710) he argued that this is 'the best of all possible worlds' —a thesis Voltaire would ridicule through his Pangloss in Candide— contending that God, in his infinite goodness and wisdom, had to choose among infinite possible worlds the one that maximises total good despite containing an unavoidable minimum of metaphysical, physical and moral evil. He also conceived the project of a characteristica universalis, a universal symbolic logical language capable of reducing all reasoning to mechanical calculation, and designed one of the earliest mechanical calculators capable of multiplication and division —a striking anticipation of modern formal logic and, indirectly, of computing. He was also a co-founder and first president of the Berlin Academy of Sciences.