LEIBNITZ or LEIBNIZ, GOTTFRIED WILHELM (1646-1716), philosopher, mathematician and man of affairs, was born on July I, 1646 at Leipzig, where his father was pro fessor of moral philosophy. Though the name Leibniz, Leibnitz or Lubeniecz was originally Slavonic, his ancestors were German, and for three generations had been in the employment of the Saxon Government. Young Leibnitz was sent to the Nicolai school at Leipzig, but, from 1652 when his father died, seems to have been for the most part his own teacher. From his father he had acquired a love of historical study. The German books at his command were soon read through, and with the help of two Latin books—the Thesaurus Chronologicus of Calvisius and an illus trated edition of Livy—he learned Latin at the age of eight. His father's library was now thrown open to him, to his great joy, with the permission, "Tolle, lege." Before he was 12 he could read Latin easily and had begun Greek; he had also remarkable facility in writing Latin verse. He next turned to the study of logic, at tempting already to reform its doctrines, and zealously reading the scholastics and some of the Protestant theologians.
At the age of 15, he entered the University of Leipzig as a law student. His first two years were devoted to philosophy under Jakob Thomasius, a Neo-Aristotelian, who is looked upon as hav ing founded the scientific study of the history of philosophy in Germany. It was at this time probably that he first made ac quaintance with the modern thinkers who had already revolution ized science and philosophy, Francis Bacon, Cardan and Cam panella, Kepler, Galileo and Descartes; and he began to consider the difference between the old and new ways of regarding nature. He resolved to study mathematics. It was not, however, till the summer of 1663, which he spent at Jena under E. Weigel, that he obtained the instruction of a mathematician of repute ; nor was the deeper study of mathematics entered upon till his visit to Paris and acquaintance with Huygens many years later. The next three years he devoted to legal studies, and in 1666 applied for the degree of doctor of law, with a view to obtaining the post of assessor. Being refused on the ground of his youth he left his
native town for ever. The doctor's degree refused him there was at once (Nov. 5, 1666) conferred on him at Altdorf—the uni versity town of the free city of Nuremberg—where his brilliant dissertation procured him the immediate offer of a professor's chair. This, however, he declined, having, as he said, "very dif ferent things in view." Leibnitz, not yet 21 years of age, was already the author of several remarkable essays. In his bachelor's dissertation De principio individui (1663), he defended the nominalistic doctrine that individuality is constituted by the whole entity or essence of a thing; his arithmetical tract De complexionibus, published in an extended form under the title De arte combinatoria (1666), is an essay towards his life-long project of a reformed symbolism and method of thought; and besides these there are juridical essays, including the Nova methodus docendi discendique juris, written in the intervals of his journey from Leipzig to Altdorf. This last essay is remarkable, not only for the reconstruction it attempted of the Corpus Juris, but as containing the first clear recognition of the importance of the historical method in law. Nuremberg was a centre of the Rosicrucians, and Leibnitz, busying himself with writings of the alchemists, soon gained such a knowledge of their tenets that he was supposed to be one of the secret brotherhood, and was even elected their secretary. A more important result of his visit to Nuremberg was his acquaintance with Johann Christian von Boyneburg (1622-72), formerly first minister to the elector of Mainz, and one of the most distinguished German statesmen of the day. By his advice Leibnitz printed his Nova methodus in 1667, dedicated it to the elector, and, going to Mainz, presented it to him in person. It was thus that Leibnitz entered the service of the elector of Mainz, at first as an assistant in the revision of the statute-book, afterwards on more important work.