GOTTFRIED WILHELM, was born at Leipzig on the 3rd of July 1646. At the age of six he lost his father, Frederic Leibnitz, the Professor of Ethics in the University of Leipzig, from whom he inherited a considerable fortune and a valuable library. The latter part of his heritage proved the more useful, for with its aid he may be said to have educated himself, although he attended from his early years the Nicolai School of his native city. Impatient of the slow progress at school, he began to read in private all the Latin and Greek authors that fell in his way, with so much profit, that before he was twelve (as he says himself), he "understood the Latin writers tolerably well, began to lisp Greek, and wrote verses with singular success." For logic, which he began to study soon afterwards, he showed as great an aptitude. In his fifteenth year he entered the University of Leipzig, where, though his principal study was law, he devoted himself to many other branches of knowledge, and especially to mathematics and philosophy. After passing a year in the study of the former science, under the celebrated Ehrhard Weigel at Jena, he returned to Leipzig, and took the degree of Bachelor in Philosophy in 1663. About this time he began to peruse with ardour the writings of Plato and Aristotle, and he used to spend entire days in a wood near Leipzig in the vain attempt to reconcile their systems. His acquaintance, however, with Greek philosophy was convinced by his metaphysical dissertation, De Principio Individuationis, which was read in 1664, when he graduated as Master in Philosophy. In his twentieth year, being refused at Leipzig, on account of his youth, as a candidate for a Doctor of Laws, he repaired to the University of Altorf, where he took his degree. His exercise on this occasion, which was afterwards published under the title De Casibus in Jure Perplexis, elicited great general applause, and procured for him the offer of a law professorship at Altorf. This he declined, and repairing to Nuremberg, chose rather to enter a society of alchemists, which he found existing there. Collecting all the current terms in books of alchemy, he wrote a letter, which, though unintelligible to himself, so favourably impressed the society, that he was forthwith introduced into their meeting, and chosen secretary. About this time the Baron de Boineburg, chancellor to the Elector of Mentz, came to Nuremberg, and was so captivated by the learning and genius of Leibnitz, that he advised him to devote himself to jurisprudence and history, and with that intent to remove to Frankfort-on-the-Main, where he promised to obtain for him some office under the elector, his master. This advice Leibnitz followed; and the result of his studies at Frankfort appeared in his Nova Methodus discendi docendique Jurisprudentiae, published in 1667. In 1668, at the request of Boineburg, he wrote a treatise, supporting the claims of the Prince of Neuburg to the elective throne of Poland, which was then vacant, and sought by a crowd of candidates. This work, though elaborately written in Latin, and containing sixty propositions rigorously deduced from a series of axioms, did not attain its direct object. Neuburg was rejected; but, as a reward for his services, Leibnitz was nominated, through the influence of Boineburg, an electoral councillor. With an ever-active ingenuity, he formed a project at this period of re-casting the Encyclopaedia of Alstedius, by rendering it more comprehensive, by introducing the articles in the order of the subjects, rather than in the order of the alphabet, and by appending to the treatise on each science a condensed account of its origin and progress, and of the authors who have treated it in detail. This design, one of the favourite ideas of the rest of his life, was never executed. In 1670, for the purpose of vindicating the works of Aristotle, he followed the unusual plan of editing a work of Nizolii against Aristotle, and expressing his own views in the preface and notes. His bold but paradoxical treatises, Theoria Motus Abstracti, and Theoria Motus Concreti, appeared in 1671. In the same year he was employed by Boineburg to write a defence of the doctrine of the Trinity against the attacks of the Pole, Wissowatus, and he produced his Sacramenta Trinitatis per novae Argumenta logica defensa.

In 1672 Leibnitz accompanied the son of his patron Boineburg to Paris. Here, amid distractions of every kind, he devoted his time almost exclusively to mathematics, a study in which he confessed himself to have been hitherto merely a tyro. His newly-formed intimacy with Huygens, and his eager perusal of the works of Galileo and Descartes, inspired him with ardour in his new researches; and he attempted, with great ingenuity, but with little success, to reconstruct and render perfect the arithmetical machine of Pascal. An offer made at this time, by the Academy of Sciences, to admit him into their body as a pensioner, on condition that he embraced the Romish faith, was declined.

On the death of Baron de Boineburg in 1673, being released from his duties at Paris, he visited England, and was received at once into the society of Boyle, Oldenburg, Collins, Wallis, Gregory, and Newton, and was elected a member of the Royal Society. The death of the Elector of Mentz in 1674, which left him without a patron, induced him to communicate his embarrassments to the Duke of Brunswick-Lunenburg, who immediately tendered him the office of a councillor, with a pension and the liberty of non-residence. Leibnitz accordingly returned to Paris to prosecute his mathematical studies. After a brief sojourn, he paid a second visit to England, and repaired, by way of Holland, to the court of his new patron at Hanover, in 1675. Here he lived in a style highly congenial to his taste, employed in enriching the ducal library with valuable works and manuscripts, and receiving the full sympathy and assistance of his benefactor. About the same time, he was engaged in writing his De Jure Suprematus et Legationis Principium Germaniae, and in furthering the plan of publishing the Acta Eruditorum, the first volume of which appeared at Leipzig in 1682.

On the death of the Duke, in 1679, his successor, Prince Ernest Augustus, afterwards George I of England, retained the same favour for Leibnitz, and employed him to write the History of the House of Brunswick. In pursuit of materials for this task, he spent three years travelling through Franconia, Bavaria, Swabia, Austria, and Italy, searching libraries, archives, tombs, convents, charters, old manuscripts, and rare books, and amassing, in addition to the documents requisite for his History, materials available for philology, geology, and the philosophy of history. The first digest of some of these materials was his great work Codex Juris Gentium Diplomaticus, published in 1693, and followed by a second volume in 1700. This book, though a mere collection of manifestoes, treaties, declarations, and Leibnitz, other public documents, is accompanied by an able preface, containing, amid many original views on the principles of natural law, his system of ethics. His accumulations supplied the matter of another work, Accessiones Historiae, published in 1698; but not until the publication of the Scriptores Rerum Brunsvicensium in 1707–11, did they appear to be applied to the purpose for which they had been intended. Even this latter work was designed merely as an introduction to his History, of which he left nothing but a bare outline, published after his death in the Acta Eruditorum for 1717. In this outline he proposes to begin the History by a dissertation on the state of the globe, and specially of Germany, before the creation; and after an account of the manners and languages of the various tribes that successively settled in that country, to end with the real History of the House of Brunswick, including, among less important subjects, a notice of all their intermarriages and alliances with other families. His general opinions on the first of these subjects were published in his Protogara, a posthumous essay, which entitles its author to be called the Founder of geology.

In 1699 he became a member of the Royal Academy of Sciences at Paris. In the following year he co-operated with the Elector of Brandenburg (afterwards Frederic I. of Prussia), in organizing a Royal Academy of Sciences at Berlin, and was rewarded for his valuable counsel with the office of President of the new institution. To the Miscellanea Berolinensis, which the Academy afterwards published, Leibnitz contributed many valuable papers. A correspondence which he had for a long time maintained with Bossuet touching a plan for the reunion of the Catholics and Protestants came about this time to an unsuccessful termination. He was also engaged in a vain attempt to construct a universal language; but of his long and deep meditations upon this subject, nothing remains except a few hints found among his papers after his death.

In answer to the sceptical views of Bayle on the origin of moral evil, Leibnitz, in 1710, published his most complete work, the Theodicee, containing his chief opinions on metaphysics and theology, and, among others, his doctrines of pre-established harmony and optimism. So courteous and tolerant was he, in this work, towards his opponents, that several eminent men unjustly suspected him of favouring the doctrines he refuted. In 1711, Peter the Great, requesting an interview with him at Torgau, consulted him regarding the civilization of his empire, and, along with a pension, conferred upon him the dignity of a privy councillor. His latter days were embittered by his vehement controversy with Newton, touching the discovery of the differential calculus. For some time he had been grievously afflicted by fits of the gout, and having, amid his multifarious acquirements, a slight knowledge of medicine, he tried a remedy on the 14th of November 1716, which, after producing violent spasms, caused his death in less than an hour. His tomb is marked by a monument in the form of a small temple, and bearing the inscription Osca Leibnitii.

Leibnitz was about the middle size, and had a spare but vigorous frame, a pleasant countenance, and keen eyes. His early-formed habit of incessant study had given him an habitual stoop, and changed his hair prematurely to grey. Invariably pursuing his studies far into the night, he sometimes denied himself the repose of his couch, and after sleeping a few hours in his chair, resumed his labours with the returning light. This abstinence he is said to have practised for several successive weeks; and some of his deep meditations kept him fixed in his chair, with scarcely an intermission, for several days together. He was equally fond of reading and contemplation. Perusing books on almost every subject, he assisted his recollection by taking short notes of their contents; but even this small aid was often unnecessary. So accurate and tenacious was his memory, that at the age of seventy he could recite long passages from Virgil without committing a single mistake; and so well assorted was his extensive information, that George I. was wont to call him a "living dictionary." His correspondence, which comprised the most illustrious names in Europe, and extended even to China, occupied a great portion of his time. Preferring solitude to society, he was, nevertheless, as animated and eager in conversation as in study; ready and fluent in expressing his thoughts; easily irritated, but as easily appeased. Though a zealous advocate of some of the great doctrines of Christianity, he was characterized by a wide religious tolerance, which, more than the character of his recorded opinions, laid him open to the charge of a secret leaning to the Roman faith. This charge, founded on an unfinished manuscript of his, which was afterwards published under the title of Systema Theologicum, has been shown by Dr Gubrauer, in his life of Leibnitz, to be inconsistent with the life and previous writings of Leibnitz. Kring and Schulze have also written elaborate apologies on the subject, and the charge is now wholly abandoned. For his philosophy and opinions, see Dissertations I., II., and IV.

The principal sources of the biography of Leibnitz are—his Life by Brucker, in the Historia Critica Philosophiae; his Elogie by Fontenelle, in the Hist. de l'Acad. des Sciences de Paris, 1716; Bailly's Elogie de M. de Leibnitz, 1769; Kästner's Lobeschrift auf Leibnitz, Altenb. 1769; but more especially his Biographies by Gubrauer, 2 vols. Breslau, 1842, and by Vogel, Leipzig, 1846. The works of Leibnitz have been singularly unfortunate in point of editing. His miscellaneous papers seem an exhaustless mine from which new treasures are continually brought to light. Four quarto volumes of posthumous works were published by Raspe in 1765; but these find no place in the Opera Omnia, published by Dutens in 1768. Of recent editions the most worthy of notice are those by Erdmann, Berlin, 1839-40; the Deutsche Schriften by Gubrauer, Berlin, 1838; Œuvres de Leibnitz par M. A. Jacques, Paris, 1842; and the Gesammelte Werke, edited by Pertz, Hanover, 1847-56, not yet completed.