Born: 7/1/1646   Died: 11/14/1716

G.W. Leibniz was one of the great 17th century rationalists. Most of his prodigious philosophical output comes in the form of essays and letters, but Leibniz also wrote two book-length works: the Theodicy, an attempted solution to the problem of evil, and the New Essays on Human Understanding, a critical commentary on Locke's views. Against Locke, Leibniz argued, among other things, for innate ideas. In metaphysics, Leibniz is best known for his theory of monads, a theory most fully expounded in his Discourse on Metaphysics and The Monadology. Other important elements of Leibniz's thought include the identity of indiscernibles, minute perceptions, and the doctrine of pre-established harmony. Leibniz's thesis that the actual world is the best possible world was famously ridiculed by Voltaire in Candide. In addition to philosophy, Leibniz also made important contributions to many other fields, including logic, mathematics, physics, and geology.