Descartes, who in the family circle was known as Du Perron, from a small estate destined for his inheritance, soon showed, say the chroniclers, an inquisitive mind, which made his father style him his philosopher. He was sent off at the age of eight to the school of La Flèche, which Henry IV. had lately founded and endowed for the J esuits, and there he continued from 1604 to 1612. Of the education there given, of the equality maintained among the pupils, and of their free intercourse, Descartes at a later period spoke in terms of high praise. He himself enjoyed exceptional privileges; his feeble health excused him from the morning duties, and thus early he acquired the habit of matutinal reflection in bed, which clung to him throughout life. Even then he had begun to distrust the authority of tradition and his teachers.

Two years before he left school he was selected as one of the twenty-four gentlemen who went forth to receive the heart of the murdered king as it was borne to its resting-place at La Flèche. At the age of sixteen he went home to his father, who was now settled at Rennes, and had taken a second wife from Brittany. During the winter of 1612 he completed his preparations for the world by lessons in horsemanship and fencing; and then in the spring of 1613, he started as his own master to taste the pleasures of Parisian life. Fortunately the spirit of dissipation does not seem to have carried him any perilous lengths; the worst we hear of is a passion for gaming. Here, too, he made the acquaintance of Claude Mydorge, one of the foremost mathematicians of France, and renewed an early intimacy with Marin Mersenne, an old fellow-student, senior by some years, at La Flèche, and now become Father Mersenne, of the order of Minim Friars. The withdrawal of the latter in 1614 to a post in the provinces was the signal for Descartes to abandon social life and shut himself up for nearly two years in a secluded house of the Faubourg St Germain. Accident, however, betrayed the secret of his retirement; he was compelled to leave his mathematical investigations, and to take part in entertainments, where the only thing that chimed in with his theorizing reveries was the music. The scenes of horror and intrigue which marked the struggle for supremacy between the various leaders who aimed at guiding the politics of France made Paris no fit place for a student, an<l held out little honourable prospect for a soldier. Accordingly, in May 1617, Descartes, now twenty-one years of age, set out for the Netherlands and took service in the army of Prince Maurice of Orange, one of the greatest generals of the age, who had been engaged for some time in a war with the Spanish forces in Belgium. At Breda he enlisted as a volunteer, and the first and only pay which he accepted he kept as a curiosity through life. There was a lull in the war; and the Netherlands were distracted by the quarrels of Gomarists and Arminians. During the leisure thus arising, Descartes one day, as he roved through Breda, had his attention drawn to a placard in the Dutch tongue; and as the language, of which he never became perfectly master, was then strange to him, he asked a bystander to interpret it into either French or Latin. The stranger, who happened to be Isaac Beeckman, principal of the college of Dort, offered with some surprise to do so into Latin, if the inquirer would bring him a solution of the problem,—for the advertisement was one of those challenges which the mathematicians of the age, in the spirit of the tournaments of chivalry, were accustomed to throw down to all comers, daring them to discover a geometrical mystery known as they fancied to themselves alone. Descartes promised and fulfilled; and a friendship grew up between him and Beeckman—broken only by the literary dishonesty of the latter, who in later years took credit for the novelty contained in a small essay on music (Compendium Musicae) which Descartes wrote at this period and intrusted to Beeckman.

After thus spending two years in Holland as a soldier in a period of peace, Descartes, in July 1619, attracted by the news of the impending struggle between the house of Austria and the Protestant princes, consequent upon the election of the palatine of the Rhine to the kingdom of Bohemia, set out for Upper Germany, and volunteered into the Bavarian service. The winter of 1619, spent

ín quarters at Neuburg on the Danube, was the critical period in his life. Here, in his warm room (dans un poêle), he indulged those meditations which afterwards led to the Discourse of Method. It was here that, on the eve of St Martin’s day, he “was filled with enthusiasm, and discovered the foundations of a marvellous science.” He retired to rest with anxious thoughts of his future career, which haunted him through the night in three dreams, that left a deep impression on his mind. “Next day,” he -continues, “I began to understand the first principles of my marvellous discovery.” The date of his philosophical conversion is thus fixed to a day. But the light was as yet dim; he had only glimpses of a method which should invigorate the syllogism by the co-operation of ancient geometry and modern algebra. For during the year that elapsed before he left Swabia (and whilst he sojourned at Neuburg and Ulm), and amidst his geometrical studies, he would fain have gathered some knowledge of the mystical wisdom attributed to the Rosicrucians; but the Invisibles, as they called themselves, kept their secret, and he found them not. His restlessness of spirit is well shown by a vow (which he himself records with the date of September 23, 1620), to make a pilgrimage to Loretto—“if possible, on foot from Venice; if not, in the most devout manner he could.” 3 Soon after the Bavarian troops were ordered into active service. He was present at the battle of Prague, where the hopes of the elector palatine were blasted (9th November 1620), passed the winter with the army in Southern Bohemia, and next year served under Count Boucquoi in Hungary. On the death of this general Descartes quitted the imperial service, and in July 1621 began a peaceful tour through. Moravia, the borders of Poland, Pomeiania, Brandenburg, Holstein, and Friesland, from which he re-appeared in February 1622 in Belgium, and betook himself directly to his father’s home in Brittany. The sole incident recorded of this excursion is his danger, when crossing in a small boat to Dutch Friesland, from the cupidity of the crew, who had taken him for a rich merchant, but at once abandoned their murderous designs when they saw him rise with drawn sword, in all the dignity of a French gentleman.

At Rennes, where the young family of his stepmother was growing up, Descartes probably found little to interest him; and, after he had visited the maternal estate which his father now put him in possession of, he took the opportunity of running up to Paris, where he found the Rosicrucians the topic of the hour, and heard himself credited with partnership in their secrets. A short visit to Brittany enabled him, with his father’s consent, to arrange for the sale of his property in Poitou. The proceeds were invested in such a way at Paris as to bring him in a yearly income of between 6000 and 7000 francs, a sum probably equal to more than £500 at the present day. Towards the end of the year Descartes was on his way to Italy. The natural phenomena of Switzerland, and the political complications in the Valtellina, where the Catholic inhabitants had thrown off the yoke of the Grisons and called in the Papal and Spanish troops to their assistance, delayed him some time; but he reached Venice in time to see the ceremony of the doge’s wedlock with the Adriatic. After paying his vows at Loretto, he came to Rome, which was then on the eve of a year of jubilee—an occasion which Descartes seized to observe the variety of men and manners which the city then embraced within its walls. In the spring of 1625 he returned home by Mount Cenis, observing the avalanches, 4 instead of, as his relatives hoped, securing a post in the French army in Piedmont.

For an instant Descartes seems to have concurred in the plan of purchasing a post at Châtellerault, but easily gave up the idea, and settled in Paris (June 1625), in the quarter where he had sought seclusion before. By this time he had ceased to devote himself to pure mathematics, and in company with his friends Mersenne and Mydorge was deeply interested in the theory of the refraction of light, and in the practical work of grinding glasses of the best shape suitable for optical instruments. But all the while his aim was fixed on something beyond either mathematics or physics; he was engaged with reflections on the nature of man, of the soul, and of God; and it need cause no surprise that Descartes for a while remained invisible even to his most familiar friends. But their importunity made a hermitage in Paris impossible; and a graceless friend surprised the philosopher in bed at 11 o’clock in the morning meditating on some problem, and occasionally taking notes. In disgust at the apparent hopelessness of the position for a student, Descartes started for the west to take part in the siege of La Rochelle, and entered the famine-stricken city with the victorious troops on the 30th October 1628. A meeting at which he was present after his return to Paris decided his vocation. He had expressed an opinion that the true art of memory was not to be gained by technical devices, but by a philosophical apprehension of things; and the Cardinal de Berulle, the founder of the Congregation of the Oratory, was so struck by the tone of the remarks as to impress upon the speaker the duty of spending his life in the examination of truth. Descartes accepted the philosophic mission. In the end of 1628 he left Paris, and in the spring of 1629 he settled in Holland. His financial affairs he had intrusted to the care of the Abbé Picot, and as his literary and scientific representative he adopted Père Mersenne.

Between the ages of thirty-three and fifty-three (1629-1649) Descartes lived almost entirely in Holland. Thrice only did he revisit France during that period—in 1644, 1647, and 1648. The first of these occasions was in order to settle family affairs after the death of his father in 1640. The eldest brother seems to have been disposed to take all he could, and to have expected the philosopher to be yielding in money matters. So little notice did the family think it necessary to take of a brother who had sunk to the level of literature, that a letter of René to his father, affectionately excusing his long absence, reached Rennes only after that father was lying in the tomb. The second brief visit, in 1647, partly on literary, partly on family business, was signalized by the award of a pension of 3000 francs, obtained from the royal bounty by Cardinal Mazarin in consideration of the advantages which Descartes’s investigations conferred upon mankind, and to aid him in continuing his experiments. The pension was punctually paid. The last visit in 1648 was less fortunate. A royal order summoned him to France for new honours— an additional pension and a permanent post—for his fame had by this time gone abroad, and it was the age when princes sought to attract genius and learning to their courts. But when Descartes arrived, he found Paris rent asunder by the civil war of the Fronde. He paid the costs of his royal parchment, and left for his Dutch home without a word of reproach. The only other occasions on which he was out of the Netherlands were in 1630, when he made a flying visit to England to observe for himself some alleged magnetic phenomena, and in 1634, when he took an excursion to Denmark.

During his residence in Holland he lived at thirteen different places, and changed his abode twenty-four times. In the choice of these spots two motives seem to have influenced him—the neighbourhood of a university or college, and the amenities of the situation. Franeker, one of the neatest towns in Friesland, was the seat of a university founded in 1585; Harderwyk contained a venerable gymnasium, of some note in the physical sciences and theology; Deventer possessed a seminary still well endowed, but less famous than it had been in the days of Erasmus; Utrecht acquired a university so late as 1634; and Leyden had a notable one founded in 1575. Amersfoort, where he also lived, seems to be connected with a love affair,—the only one in his life; at least it was there that his daughter Francine died in 1640, at the age of five. Amsterdam, where he often lodged, Leeuwarden in Friesland, and Dort were also residences. He once settled near Utrecht, as well as in the town; but the three spots which seem to have been most attractive were—Endegeest, a country house more than a mile north-west of Leyden, of which Sorbière has given a pleasing description in one of his letters, and the two villages of Egmond op den Hoef and Egmond the Abbey, situated between Zaandam and the ocean, in one of the prettiest localities of North Holland.

The time thus spent seems to have been on the whole happy, even allowing for some warm discussions with the mathematicians and metaphysicians of France, and for some harassing controversies in the Netherlands. Friendly agents—chiefly Catholic priests—were the intermediaries who forwarded from Dort, Haarlem, Amsterdam, and Leyden his correspondence to his proper address, which he wished kept completely secret; and Father Mersenne was only too willing to send him loads of objections and questions. During the first twenty years of his life his health had been weak and his complexion pale. After that time the disease in his frame seems to have worked itself off, not without some effervescence. This is the period of his camp life (due, as he himself says, to “heat in the liver ”), of his wanderings, enthusiasm, dreams, and vows. With his thirtieth year this struggle seems at an end; his health seems established; and the washed-out vermilion of his prime gives place to a dark olive complexion in his riper manhood. It is touching to hear his delight in the freedom from intruders. “I sleep here ten hours every night,” he writes from Amsterdam, “and no care ever shortens my slumber.” “I take my walk every day through the confusion of a great multitude with as much freedom and quiet as you could find in your rural avenues.” At his first coming to Franeker he arranged to get a cook acquainted with French cookery; but, to prevent misunderstanding, it may be added that his diet was mainly vegetarian, and that he rarely drank wine. New friends gathered round him who took a keen interest in his researches. Once only do we find him taking an interest in the affairs of his neighbours,—to ask pardon from the Government for a homicide. He continued the profession of his religion. Sometimes from curiosity he went to the ministrations of anabaptists, to hear the ranting of peasants and artisans. He carried few books to Holland with him, but a Bible and the Summa of Thomas Aquinas were amongst them. One of the recommendations of Egmond the Abbey was the free exercise there allowed to the Catholic religion. At Franeker his house was a small château, “separated by a moat from the rest of the town, where the mass could be said in safety.” And one motive in favour of accepting an invitation to England lay in the alleged leanings of Charles I. to the older church.

The best account of Descartes’s mental history during his life in Holland is contained in his letters, which extend over the whole period, and are particularly frequent in the latter half. The majority of them are addressed to Mersenne, and deal with problems of physics and musical theory (in which he took a special interest). Mathematical subjects are a common topic. Several letters between 1643 and 1649 are addressed to the Princess Elizabeth, the eldest daughter of the ejected elector palatine, who lived at the Hague, where her mother maintained the semblance of a royal court. The princess was obliged to quit Holland, but kept up a philosophical correspondence with Descartes. It is to her that the Principles of Philosophy were dedicated; and in her alone, according to Descartes, were united those generally separated talents for metaphysics and for mathematics which are so characteristically co-operative in the Cartesian system. Two Dutch friends, Zuylichem, the father of the more celebrated Huyghens, and Hoogheland, figure amongst the correspondents, not to mention various savants, professors, and churchmen (particularly Jesuits).

His residence in the Netherlands fell on the most prosperous and brilliant days of the Dutch state, under the stadtholdership of Frederick Henry (1625-1647). Abroad its navigators monopolized the commerce of the world, and explored unknown seas; at home the Dutch school of painting reached its acme in Rembrandt (1607-1669); and the philological reputation of the country was sustained by Grotius, Vossius, and the elder Heinsius. And yet, though Rembrandt’s Nightwatch is dated the very year after the publication of the Meditations, not a word in Descartes breathes of any work of art or historical learning. The contempt of aesthetics and erudition is characteristic of the most typical members of the Cartesian school, especially Malebranche. Though Descartes probably read more than some of his admirers supposed he was not in any strict sense a reader. His wisdom grew mainly out of his own reflections and experiments, calmly yet ceaselessly pursued. Of mere learning and scholarship he had no esteem. The story of his disgust, when he found that Queen Christina devoted some time every day to the study of Greek under the tuition of Vossius, is at least true in substance. It gives no evidence of science, he remarks, to possess a tolerable knowledge of the Roman tongue, such as once was possessed by the populace of Rome. In all his travels, and in the different places at which he settled, his interest seems untouched either by art or history; he looks only to the phenomena of nature and the actual aspects of human life. He was a spectator rather than an actor on the stage of the world. If he entered the army, it was merely because the position gave a vantage-grouud from which to make his observations. In the political interests which these contests involved he took no part; his favourite disciple, the Princess Elizabeth, was the daughter of the banished king, against whom he had served in Bohemia; and Queen Christina, his second royal follower, was the daughter of Gustavus Adolphus.

In many ways Descartes is a type of that self-reliant, harsh, and abstract spirit of science to which erudition and all the heritage of the past seem but elegant and unworthy trifling. The science of Descartes was physics in all its branches, but especially as applied to physiology. Science, he says, may be compared to a tree; metaphysics is the root, physics is the trunk, and the three chief branches...