Gottfried Wilhelm, Baron von Leibnitz, was born in 1646 at Leipzig, where his father was professor of Philosophy. The subject that he studied in view of a profession was jurisprudence, but first, in accordance with the fashion of the day, he made a study of Philosophy, and to it he devoted particular attention. To begin with, he picked up in Leipzig a large and miscellaneous stock of knowledge, then he studied Philosophy and mathematics at Jena under the mathematician and theosophist Weigel, and took his degree of Master of Philosophy in Leipzig. There also, on the occasion of his graduation as Doctor of Philosophy, he defended certain philosophical theses, some of which discourses are still contained in his works (ed. Dutens, T. II. P. I. p. 400). His first dissertation, and that for which he obtained the degree of doctor of philosophy, was: _De principio individui_,—a principle which remained the abstract principle of his whole philosophy, as opposed to that of Spinoza. After he had acquired a thorough knowledge of the subject, he wished to graduate also as Doctor of Laws. But though he died an imperial councillor, it was his ill fortune to receive from the Faculty at Leipzig a refusal to confer the doctorate upon him, his youth being the alleged reason. Such a thing could scarcely happen now-a-days. It may be that it was done because of his over-great philosophical attainments, seeing that lawyers are wont to hold the same in horror. He now quitted Leipzig, and betook himself to Altdorf, where he graduated with distinction. Shortly afterwards he became acquainted in Nürnberg with a company of alchemists, with whose ongoings he became associated. Here he made extracts from alchemistic writings, and studied the mysteries of this occult science. His activity in the pursuit of learning extended also to historical, diplomatic, mathematical and philosophical subjects. He subsequently entered the service of the Elector of Mayence, becoming a member of council, and in 1672 he was appointed tutor to a son of Von Boineburg, Chancellor of State to the Elector. With this young man he travelled to Paris, where he lived for four years. He at this time made the acquaintance of the great mathematician Huygens, and was by him for the first time properly introduced into the domain of mathematics. When the education of his pupil was completed, and the Baron Von Boineburg died, Leibnitz went on his own account to London, where he became acquainted with Newton and other scholars, at whose head was Oldenburg, who was also on friendly terms with Spinoza. After the death of the Elector of Mayence, the salary of Leibnitz ceased to be paid; he therefore left England and returned to France. The Duke of Brunswick-Lüneburg then took him into his service, and gave him the appointment of councillor and librarian at Hanover, with permission to spend as much time as he liked in foreign countries. He therefore remained for some time longer in France, England, and Holland.