=The Life and Writings of Leibnitz= (1646–1716). Compared with Descartes and Spinoza, Leibnitz had a life that was long in time and rich in experience. Descartes died at 54 and Spinoza at 45, while Leibnitz lived to be 70. In striking contrast with Spinoza’s career, there was no time in the life of Leibnitz after his graduation from the university that he was not in public service. He held the offices that would naturally go to the hanger-on of princes――some of them grandiose ones. While theoretically the interests of the three Rationalists were the same, Leibnitz differed from his predecessors in that his study of philosophical problems always grew out of some practical problem or political occasion. Leibnitz was not an academic thinker, and his “writings were called forth to estimate some recent book, to outline the system for the use of a friend, to meet some special difficulty, or to answer some definite criticism.” Philosophy was only one of the interests of Leibnitz. He was jurist, historian, diplomat, mathematician, physical scientist, theologian, and philologist. Leibnitz was as much at home with the theories of Plato and Aristotle of ancient time, with those of St. Thomas and Duns Scotus of mediæval time, as with the science of Descartes and Galileo. He was precocious, had a prodigious memory and a reactive mind. In the wealth of his information and the productiveness of his genius, he stands with Aristotle as unequaled. Descartes, Spinoza, and Leibnitz belonged to the inner circle of scholars of the time, but Leibnitz was also in personal touch with political affairs and in intimate acquaintance with many of the important rulers. He was in the service of the Elector of Mainz and later of George I of England when George was only Elector of Hanover. He was distinguished by Peter the Great of Russia and Ernst August, Emperor of Germany. He corresponded with Eugene of Savoy and he was ambassador to Louis XIV of France. Sophie Charlotte of Hanover, who married the King of Prussia, was especially interested in him, and he wrote for her his _Theodicy_. The three great Rationalists came from different strata of society. Descartes was a nobleman’s son, and he voluntarily relinquished the life that Leibnitz was ambitious to enjoy. Spinoza came from the lower class. Leibnitz was the son of a college professor and belonged to the upper middle class. The ambitions of Leibnitz reached for large ends, as often happens among educated people in the middle walks of life. Among other things, he tried to reconcile the Catholics and Protestants, and he tried to universalize language by getting universal characters for all languages.