To come to the life of Descartes—he was born in 1596, at La Haye in Touraine, of an ancient and noble race. He received an education of the usual kind in a Jesuit school, and made great progress; his disposition was lively and restless; he extended his insatiable zeal in all directions, pursued his researches into all systems and forms; his studies, in addition to ancient literature, embraced such subjects as philosophy, mathematics, chemistry, physics, and astronomy. But the studies of his youth in the Jesuit school, and those studies which he afterwards prosecuted with the same diligence and strenuous zeal, resulted in giving him a strong disinclination for learning derived from books; he quitted the school where he had been educated, and yet his eagerness for learning was only made the keener through this perplexity and unsatisfied yearning. He went as a young man of eighteen to Paris, and there lived in the great world. But as he here found no satisfaction, he soon left society and returned to his studies. He retired to a suburb of Paris and there occupied himself principally with mathematics, remaining quite concealed from all his former friends. At last, after the lapse of two years, he was discovered by them, drawn forth from his retirement, and again introduced to the great world. He now once more renounced the study of books and threw himself into the affairs of actual life. Thereafter he went to Holland and entered the military service; soon afterwards, in 1619, and in the first year of the Thirty Years’ War, he went as a volunteer with the Bavarian troops, and took part in several campaigns under Tilly. Many have found learning unsatisfying; Descartes became a soldier—not because he found in the sciences too little, but because they were too much, too high for him. Here in his winter quarters he studied diligently, and in Ulm, for instance, he made acquaintance with a citizen who was deeply versed in mathematics. He was able to carry out his studies even better in winter quarters at Neuberg on the Danube, where once more, and now most profoundly, the desire awoke in him to strike out a new departure in Philosophy and entirely reconstruct it; he solemnly promised the Mother of God to make a pilgrimage to Loretto if she would prosper him in this design, and if he should now at last come to himself and attain to peace. He was also in the battle at Prague in which Frederick the Elector-Palatine lost the Bohemian crown. Yet since the sight of these wild scenes could not satisfy him, he gave up military service in 1621. He made several other journeys through the rest of Germany, and then proceeded to Poland, Prussia, Switzerland, Italy and France. On account of its greater freedom he withdrew to Holland, in order there to pursue his projects; here he lived in peace from 1629 to 1644—a period in which he composed and issued most of his works, and also defended them against the manifold attacks from which they suffered,