DESCARTES, RENE, was born at La Haye, between Tours and Poitiers, iu Touraine, on the 31st of March 1596, and died at Stock holm on the 11th of February 1650, before he had completed his fifty-fourth year.
Descartes was of noble descent, being a younger son of a councillor in the parliament of Rennee. lie is one of the many instances of great delicacy of constitution being combined with the highest order of mind. His early education was among the Jesuits, who had, shortly previous, established one of their seminaries or colleges in the neighbourhood of his father's residence at La-Fhiche ; and though Descartes was one of those men who would have educated himself iu the absence of all instruction, there can be little doubt that the system adopted lu the colleges of the Jesuits was better calculated to develop the peculiar powers of the students than any other which has ever prevailed in modern Europe.
During his course in the college of Le•Floche he contracted a friend ship with Marsenne, which continued to the end of the life of that distinguished monk, and this circumstance doubtless tended much to increase the attachment of Descartes to mathematical and metaphy sical studies. Algebra was at this time studied by few, arid it had acquired but little extent and power as an instrument of investigation; whilst geometry, as it was then cultivated, feuded too much to run into a mere deduction of isolated but curious and difficult propo sitions, without much regard to the general principles upon which their analysis and syutheeis depended, or to the nature of the funda mental principles upon which geometrical reasoning was ultimately founded. The comparative novelty of the algebraic methods would give a charm to the study in a mind constituted like that of Descartes; and an examination of its first priuciples, and the operations of the mind in the actual development of the truths of geometry, would be more likely to arrest his active mind than the mere deduction of curious hut necessary coneepeoces. It is easy to conceive that his reading and course of study in the college would be somewhat desul tory, and that be often depended more upon his own innate power for going through his exercises than upon the lectures of the professor, or the books which were put into his hands. This character in Descartes was properly appreciated by his friends and tutors. He formed the determination of renouncing all books, and endeavouring to efface from his mind the knowledge which he had been taught, so as to employ the power which he had gained by the discipline of his college only to investigate the fundameutal principles of human know ledge ab initio. Still this can hardly be thought to be a suddenly
formed resolution. Even allowing this to have been a plan gradually formed, the execution of it was a Herculean task ; nor was it nuattended with personal danger, as the contemporary history of Galileo sufficieotly proves. Considering therefore that Descartes was at this time only nineteen years of age, the whole circumstance is one without a parallel in intellectual history.
Descartes wisely abstained from publishing his views at this time, or indeed his mathematical discoveries, of which there is some probability that he was in possession at this early age; but conformably with the fashion of the age among men of his social and political condition, he engaged in the profession of arms. He served first as a volunteer in the army of Holland, and then in that of the Duke of Bavaria ; and he was present at the battle of Prague in 1620, iu which he conducted himself with great intrepidity. There is no profession more inimical to the study of abstract science than that of areas, and hence Descartes soon abandoned it for the purer and more honourable career to which his previous studies and native ardour of mind were so admirably adapted. But even during his attachment to the camp he did not neglect his mathematical and philosophical inquiries. It is believed to have been during his stay at Breda that Descartes composed his Compendium Musicm, although it was not printed till after his death. Another circumstance indioative of his devotion to geometry is also narrated in connection with the same campaign, and occurring also at Breda. One day, seeing a group of people surrounding a placard, he found it written in Flemish, a language which he did not understand, and therefore applied to one of the bystanders for an explanation. This persun chanced to be Beckmann, principal of the college of Dort, who, wondering that a young soldier should take any interest in geometry—the placard being, in keeping with the practice of the age, a problem proposed as a challenge—explained the problem to him ; but is said to have displayed something of the collegiate pedantry which was then so common. Descartes however promised Lim a solution, which he sent to the principal early next morning.