Gottfried Wilhelm Leibniz (von Leibniz) (July 1, 1646 - November 14, 1716) was a German mathematician and philosopher. Leibniz occupies a prominent place in the history of mathematics and the history of philosophy. His mathematical notation has been widely used ever since it was published. His Law of Continuity and Transcendental Law of Homogeneity only found mathematical implementation in the 20th century. He became one of the most prolific inventors in the field of mechanical calculators. He invented the Leibniz wheel, used in the arithmometer, the first mass-produced mechanical calculator. He also refined the binary number system, which is at the foundation of virtually all digital computers. In philosophy, Leibniz is mostly noted for his optimism and along with Ren矇 Descartes and Baruch Spinoza, was one of the three great 17th century advocates of rationalism. The work of Leibniz anticipated modern logic and analytic philosophy, but his philosophy also looks back to the scholastic tradition, in which conclusions are produced by applying reason to first principles or prior definitions rather than to empirical evidence. He died in 1716 at the age of 70. Leibniz was so out of favor that neither George I nor any fellow courtier other than his personal secretary attended the funeral. His grave went unmarked for more than 50 years.