l'Entendement Humain," the largest and perhaps the most important of his philosophical works, was published sixty years after his death by Raspe. This treatise is in the form of a dialogue. It was occasioned by Locke's celebrated Essay, which appeared in 1690, and soon engaged the attention of Leibnitz. A short tract, entitled "Reflexions sur l'Essai de M. Locke," was written by Leibnitz about 1696, and afterwards published in the Recueil of Des Maizeaux. Some criticisms of Leibnitz are referred to in the correspondence between Locke and Molyneux in 1697. There could be little sympathy between two philosophers whose intellectual difference was so organic as Locke and Leibnitz. Locke despised what he called the "chimeras" of Leibnitz. The German philosopher accorded to his English contemporary the praise of perspicuity, but proclaimed his utter ignorance of the "demonstrative metaphysics." Psychological experience was the philosophical organ of Locke; the aim of Leibnitz was to constitute philosophy an absolute science, akin to the higher mathematics. The tendency of Locke was unsystematic and practical; that of Leibnitz was abstract, speculative, and eclectic. They were the greatest minds of their age, and each was in a manner the complement of the other. Before 1703 Leibnitz undertook the formal reply to Locke, contained in the "Nouveaux Essais," which he completed in the following year. The death of Locke in 1704 caused an indefinite postponement of the publication of the work. This, the philosophical masterpiece of its author, contains the substance of all that has been advanced by him on behalf of his speculative system against the school of Locke, and is the ablest of all the many criticisms which the Essay on Human Understanding has drawn forth. The metaphysical philosophy of Leibnitz may be regarded as a reconstruction of Cartesianism on a broader basis, and with important modifications, suggested by the consequences into which the Cartesian system had been resolved by Malebranche and Spinoza. The systems of Locke and Leibnitz are in truth reactions, in opposite directions, against the earlier philosophy as involving these consequences. Cartesianism, which places the essence of matter in extension, and of mind in thought, tends to eliminate altogether finite causes and substances. Malebranche accordingly rejected secondary causes, and virtually resolved all the changes in the universe into the agency of God. Spinoza, advancing further, deduced all finite existence from the One Absolute Substance. The metaphysic of Leibnitz is fundamentally a theory of the essential activity of the substances or monads of existence, which possess, according to him, a power of spontaneous development. In these unextended forces or monads we obtain, says Leibnitz, the a priori idea of substance. Their individuality consists in the series of changes through which each passes. These changes are termed perceptions. Some perceptions are unconscious, and among these are the elements of which the material world is the issue. There are also the self-conscious souls of men, containing in themselves the seeds of necessary truth, developed through experience. Creation implies the existence of the Monas Monadum, or Supreme Substance, whence all that is finite has been derived, and in which it all finds its explanation. The universe is thus a vast collection of unextended spiritual forces, which evolve themselves in a pre-established harmony or cosmical order, and which, in its final issues, constitutes a scheme of optimism. The created universe is a harmonious theocracy which expresses the attributes of the one perfect Being. From his eternal throne its several streams of elementary existence have taken their rise. They have flowed, and they must continue to flow, in the courses into which he sent them in the beginning; and notwithstanding the dark shades in which many of them are enveloped, they are recognized by Omniscience as the only possible, and therefore most glorious illustration by creation of the pure fountain in which they originated. The speculations of Leibnitz, like those of Berkeley, though by a different route, thus conduct to immaterialism. His "demonstrative metaphysics" parts from body and extension before it resolves nature into its elements. The experimental philosophy of Berkeley fails to find in the phenomena of perception evidence of the existence of an extended substance, independent of the conscious spirit that perceives them. Both have contributed to break up the crude popular notion of the material world in which so much error has originated. We cannot enlarge on Leibnitz's criticism of the reasoning of Locke regarding innate ideas and principles independent of education and experience, from which he infers the existence of elements in human knowledge independent of external and internal sense. Our knowledge, while dependent on the contingencies of experience, cannot, says Leibnitz, be analyzed into these; developed through sense, it cannot be dissolved into sense. This, with his theory of unconscious mental agency (akin to his doctrine of unconscious perception in monads), his critical objections to Locke's hypothesis of interrupted consciousness, his doctrine of space and a vacuum, and his vindication of syllogism, are among the most important parts of the psychology and logic of the "Nouveaux Essais."
Eckhart has recorded some particulars regarding the personal appearance and manner of life of this philosopher. He was of middle stature, rather spare in person, and short-sighted. His constitution was vigorous. Like Des Cartes, Spinoza, Locke, Hume, and Kant, Leibnitz was never married. He had no domestic establishment, and no fixed hours for his meals, which he took when convenient for his studies. These were pursued without intermission, and often for days together he did not leave his chair. In his journeys he often in his carriage carried on mathematical or philosophical investigations, which were afterwards published in the journals. A great part of the "Nouveaux Essais" is said to have been written in this manner. His c orrespondence, as already mentioned, was very extensive, and occupied a great part of his time. He may be classed with Bayle and Hamilton as the most learned of philosophers; and he was perhaps the first among the moderns to read the literature of opinion in an eclectic spirit, with an appreciation of all the great systems of the past, and a recognition of the mutual relations of different systems. In the course of his immense reading it was his habit to make extracts in his commonplace-book, and to note, often on fragments of paper, his critical remarks on what he read. His extraordinary memory made it almost unnecessary for him to refer afterwards to what he thus wrote, for Leibnitz was one of those prodigies of memory of whom anecdotes are recorded. He forgot almost nothing that he had once read or heard. In his old age he could recite the most beautiful passages of the ancient classics, and whatever else he had read in his youth. But though he read much he reflected more. He is illustrious, like our own Hamilton, for the mental power which can unite extraordinary reading with a ceaseless energy of thinking. In most parts of knowledge it may well be said that he was self-taught, and he always struggled for deeper insight into things than that attained by other minds. He preferred solitary meditation to conversation, but when once roused in social intercourse he spoke with interest, and even indulged in playful sallies. In accordance with his liberal and tolerant spirit, it was his habit to speak well of others, and to put the best construction on their words and actions. "When I err in my opinion of men," he was wont to say, "I prefer to err on the side of charity, and so too as regards their writings. I seek there for what is worthy of praise, rather than of blame; and there are few books or persons whence I may not in some form draw wisdom and useful instruction." Such was the spirit of Leibnitz, and to these comprehensive sympathies we may trace the modern philosophy of the history of man and of human opinion.
A collected edition of the works of Leibnitz was published by Dutens in 6 vols. 4to, at Geneva in 1768. His philosophical works were published three years earlier by Raspe, and republished, with many additions, in 1840, in the well-known edition of Erdmann. Since then various monographs and tracts from the Leibnitzian MSS. at Hanover have appeared, and a complete edition of his works is now in course of publication—A. C. F.
LEICESTER, Robert Dudley, Earl of, one of Queen Elizabeth's principal favourites, was born about the year 1531, and was the son of John Dudley, duke of Northumberland, who perished on the scaffold in 1553.—(See Dudley, John.) Robert was implicated in his father's offence, and narrowly escaped his fate. He was pardoned by the queen and liberated in 1554, and three years later was appointed master of the ordnance at the siege of St. Quentin. On the accession of Elizabeth he was at once taken into favour, made master of the horse, a privy councillor, and a knight of the garter, and obtained profuse grants of manors and castles. He was inferior to all the other favourites of the maiden queen both in capacity and in character; but his handsome person, insinuating address, and elegant accomplishments seem completely to have gained the heart of Elizabeth, and made him for thirty years the most influential subject in England. His first wife, Amy, daughter of Sir John Robsart, whom he
