WOLFF, CHRISTIAN (1679-1754), is an important figure in the history of philosophy, and his life has more dramatic interest than is usually the case with an academic teacher. He was the son of a tanner, and was born at Breslau on the 24th January 1679. His father had dedicated him before his birth to a life of learning, having been disappointed himself in similar aspirations, and Wolff accordingly received a gymnasium training in Breslau, whence he proceeded in 1699 to the university of Jena. Mathematics and physics formed at first his chief attraction, to which he soon added philosophy. He studied the Cartesian philosophy as well as the works of Grotius and Pufendorf, but was chiefly influenced by Tschirnhausen's Medicina ))Eustis. In 1703 he qualified as privat-docent in the university of Leipsic, where he lectured till 1706, when he was called as professor of mathematics to Halle. Before this time lie had made the acquaintance of Leibnitz, of whose philosophy his own system is a modification. In Halle Wolff limited himself at first to mathematics, but on the departure of a colleague he annexed physics, and presently included in his lectures all the main philosophical disciplines. He followed the example of Thomasius in lecturing in German instead of Latin. This fact, and the remarkableclearness of his exposition, causedhis class-rooms to be crowded. He also became known as a writer to a wider circle, and was made member of the Royal Society of London and the Academy of Berlin. But the claims which Wolff advanced on behalf of the philosophic reason appeared impious to his theological colleagues. Halle was the headquarters of Pietism, which, after a long struggle against the rigidity of the older Lutheran dogmatism, had itself assumed the characteristics of a new orthodoxy. This orthodoxy, represented by Joachim Lange and A. H. Francke, considered the cause of supernaturalism endangered by a philosophy which professed by the unassisted reason to present the whole universe as a rational and necessarily determined system. 1rVolff's professed ideal was to base theological truths on evidence of mathematical certitude. Personal grounds accentuated the bitterness. Strife broke out openly in 1721, when Wolff, on the occasion of laying down the office of pro-rector, delivered an oration " On the Moral Philosophy of the Chinese," in which he praised the purity of the moral precepts of Confucius, pointing to them as an evidence of the power of human reason to attain by its own efforts to moral truth. The attacks and accusations in connexion with this address were unsuccessful at the time, but -Wolff continued to give offence to his colleagues, and to Lange in particular, by his action in the filling up of university chairs, and in 1723 a disappointed pupil, a docent in the same university, published a hostile criticism upon Wolff's system, at the instigation, it is said, of Lange. This was contrary to university etiquette and statute, and 'Wolff somewhat injudiciously appealed to the Government for an interdict upon such attacks. He succeeded in obtaining this, but his enemies retaliated by sending to court a united representation of the dangerous character of his views. Through a worthless courtier, they gained the ear of the king, Frederick William I., by a concrete example, which touched him most nearly. if one of His Majesty's famous grenadiers at Potsdam should desert, the king would have no right, it was represented, upon the principles of Wolff, to punish the man, seeing that he only did what it was necessarily predetermined that he should do. The result of this representation was swifter and more drastic than Wolff's bitterest enemies had calculated on. On the 13th November 1723 a cabinet order arrived in Halle deposing Wolff from his office, and commanding him to leave Halle and quit Prussian territory within forty-eight hours on pain of a halter. The same day Wolff passed into Saxony, and presently proceeded to Marburg, to which university he had received a call before this crisis. The landgrave of Hesse received him with every mark of distinction, and the circumstances of his expulsion drew universal attention to his philosophy. It was everywhere discussed, and over two hundred books and pamphlets appeared for or against it before 1737, not reckoning the systematic treatises of Wolff and his followers. The seventeen years which Wolff spent at Marburg witnessed the publication of his chief works, and the rise of his philosophy to almost undisputed sway throughout Germany. His earlier treatises were, like his lectures, composed in German : - a treatise on logic, called Verniinflige Gedanken von den Rriiften des inenschlichen Verstandes (1712) ; a metaphysic, Verniinftige Cedanken von Gott, der Welt, send der Seele des Menschen, ouch oiler Dive iiberhaupt (1719) ; treatises on ethics and politics with similar titles (1721) ; three on the philosophy of nature (1723-4-5), followed by an encyclopaedic review of his system in 1726. From that time he began to go over the same ground more fully and methodically in a series of Latin works. The logic, ontology, cosmology, and empirical psychology appeared between 1728 and 1732, followed by the rational psychology and natural theology in 1734. Meanwhile, after some years the king of Prussia made overtures to Wolff to return, and in 1739, by the irony of events, a cabinet order prescribed the study of the Wolffian philosophy to all candidates for ecclesiastical preferment. In 1740 Frederick William died suddenly, and one of the first acts of his successor, Frederick the Great, was to recall Wolff to Halle on the most flattering and advantageous terms. His entry into Halle on the 6th of December 1740 partook of the nature of a triumphal procession. In 1743 he became chancellor of the university, and in 1745 he received the title of " freiherr " from the elector of Bavaria. But, though he was thus loaded with honours, and his philosophy everywhere triumphant, he found that he had outlived his power of attracting the academic youth. His matter was no longer fresh, nor were his own powers what they had been when he left Halle seventeen years before, and he had the bitter experience of lecturing to empty class-rooms. He died on the 9th April 1754, in the seventy-sixth year of his age, fourteen years after his return to Halle.

The Wolffian philosophy held almost undisputed sway in Germany till it was displaced by the Kantian revolution. It is essentially a common-sense adaptation or watering-down of the Leibnitian system; or, as we can hardly speak of a system in connexion with Leibnitz, Wolff may be said to have methodized and reduced to dogmatic form the thoughts of his great predecessor, which often, however, lose the greater part of their suggestiveness in the process. Since his philosophy disappeared before the influx of new ideas and the appearance of more speculative minds, it has been customary to dwell almost exclusively on its defects - the want of depth or freshness of insight, and the aridity of its neoscholastic formalism, which tends to relapse into verbose platitudes. But this is to do injustice to Wolff's real merits. These are mainly his comprehensive view of philosophy, as embracing in its survey the whole field of human knowledge, his insistence everywhere on clear and methodic exposition, and his confidence in the power of reason to reduce all subjects to this form. To these must be added that he was practically the first to "teach philosophy to speak German." It will be seen that these merits concern the form rather than the matter of philosophy, the latter being mainly derived from Leibnitz, with some modifications in the sense of the older scholastic Aristotelianism. The Wolilian system retains the determinism and optimism of Leibnitz, but the monadology recedes into the background, the monads falling asunder into souls or conscious beings on the one hand and mere atoms on the other. The doctrine of the pre-established harmony also loses its metaphysical significance, and the principle of sufficient reason introduced by Leibnitz is once more discarded in favour of the principle of contradiction which Wolff seeks to make the fundamental principle of philosophy. Philosophy is defined by him as the science of the possible, and divided, according to the two faculties of the human individual, into a theoretical and a- practical part. Logic, sometimes called philosophise rationalis, forms the introduction or proptedeutic to both. Theoretical philosophy has for its parts ontology or phitosonhia prima, cosmology, rational psychology, and natural theology ; ontology treats of the existent in general, psychology of the soul as a simple non-extended substance, cosmology of the world as a whole, and rational theology of the existence and attributes of God. These are best known to philosophical students by Kant's treatment of them in the Critigae of Pure Reason. Practical philosophy is subdivided into ethics, economies, and politics. Wolf 's moral principle is the realization of human perfection. (A. SE.)