JOHANN CARLSTIAN VON, a celebrated German mathematician and philosopher, was born at Breslau, on the 24th of January 1679. After having been well instructed in the rudiments of learning and science in his own country, Wolff prosecuted his studies successively in the universities of Jena and Leipzig. At the age of twenty-six he had acquired so much distinction that he was appointed professor of mathematics, and soon afterwards of philosophy, in the university of Halle. After Leibnitz had published his Theodicea, Wolff, struck with the novelty of the edifice which that philosopher had raised, assiduously laboured in the investigation of new metaphysical truths. He also digested the elements of mathematics in a new method, and attempted an improvement of the art of reasoning, in a treatise on the powers of the human understanding. Upon the foundation of Leibnitz's doctrine of monads, he formed a new system of cosmology and pneumatology, digested and demonstrated in a mathematical method. His work, entitled Thoughts on God, the World, and the Human Soul, was published in the year 1719; to which were added, in a subsequent edition, Heads of Ethics and Policy. Wolff was now rising towards the summit of philosophical reputation, when the opinion which he entertained on the doctrine of necessity being deemed by his colleagues inimical to religion, and an oration which he delivered in praise of the morality of the Chinese having given much offence, an accusation of heresy was publicly brought against him; and though he attempted to justify himself in a treatise which he wrote on the subject of fatality, a royal mandate was issued in November 1723, requiring him to leave the Prussian dominions. Having been formerly invited by the landgrave of Hesse-Cassel to fill a professorship of mathematics and philosophy in the university of Marburg, Wolff now put himself under the patronage of that prince, who had the liberality to afford him a secure asylum. The question concerning the grounds of the censure which had been passed upon him was now everywhere freely canvassed; almost every German university was inflamed with disputes on the subject of liberty and necessity, and the names of Wolffians and Anti-Wolffians were everywhere heard. It was while residing at Cassel that the greater portion of his philosophical works were written. Philosophy was, according to Wolff, "the science of things possible, inasmuch as they are possible." He maintained the Leibnitzian doctrine of "pre-established harmony," and laboured to demonstrate the metaphysical law of sufficient reason from the logical law of contradiction, and as he commenced by begging the question under dispute, he ended, after reasoning laboriously in a circle, where the argument had begun. His philosophical works are Philosophia Rationalis, 4to, 1728; Psychologia Empirica, 4to, 1728; Philosophia Prima, sive Ontologia, 4to, 1730; Cosmologia Generalis, 4to, 1731; Psychologia Rationalis, 4to, 1734; Theologia Naturalis, 4to, 1737; Philosophia Practica Universalis 4to, 1738-39; and Philosophia Moralis, sive Ethica, 4to, 1732.

After an interval of nine years, the King of Prussia reversed his sentence of exile, and appointed him professor of the law of nature and of nations, and vice-chancellor of the university of Halle; where his return, some nine years afterwards, was welcomed with every expression of triumph. From this time he was employed in completing his Institutes of Philosophy, which he lived to accomplish in every branch except Policy. In 1745 he was created a baron by the Elector of Bavaria, and succeeded Ludwig in the office of chancellor of the university. He continued to enjoy these honours till the year 1754, when he expired on the 9th of April. He possessed a clear and methodical understanding, which, by long exercise in mathematical investigations, was particularly fitted for the employment of digesting the several branches of knowledge into regular systems; and his fertile powers of invention enabled him to enrich almost every field of science in which he laboured, with some valuable additions. The lucid order which appears in all his writings enables his readers to follow his conceptions with ease and certainty. His works are partly in German and partly in Latin. His political works consist of Jus Naturae, published from 1740 to 1748, and extend to no fewer than eight quarto volumes, and Jus Gentium, Halle, 1752.