83. Nine years more elapsed, during which Descartes, though he quitted military service, continued to observe mankind in various parts of Europe, still keeping his heart fixed on the great aim he had proposed to himself, but, as he confesses, without having framed the scheme of any philosophy beyond those of his contemporaries. He deemed his time of life immature for so stupendous a task. But at the age of thirty-three, with little notice to his friends, he quitted Paris, convinced that absolute retirement was indispensable for that rigorous investigation of first principles he now determined to institute, and retired into Holland. In this country he remained eight years so completely aloof from the distractions of the world, that he concealed his very place of residence, though preserving an intercourse of letters with many friends in France. |His publications.| 84. In 1637 he broke upon the world with a volume containing the Discourse upon Method, the Dioptrics, the Meteors, and the Geometry. It is only with the first that we are for the present concerned.[227] In this discourse, the most interesting perhaps of Descartes’ writings, on account of the picture of his life, and of the progress of his studies that it furnishes, we find the Cartesian metaphysics, which do not consist of many articles, almost as fully detailed as in any of his later works. In the Meditationes de Prima Philosophia, published in Latin, 1641, these fundamental principles are laid down again more at length. He invited the criticism of philosophers on these famous Meditations. They did not refuse the challenge; and seven sets of objections, from as many different quarters, with seven replies from Descartes himself, are subjoined to the later editions of the Meditations. The Principles of Philosophy, published in Latin in 1644, contains what may be reckoned the final statement, which occupies most of the first book, written with uncommon conciseness and precision. The beauty of philosophical style which distinguished Descartes is never more seen than in this first book of the Principia, the translation of which was revised by Clerselier, an eminent friend of the author. It is a contrast at once to the elliptical brevity of Aristotle, who hints, or has been supposed to hint, the most important positions in a short clause, and to the verbose, figurative declamation of many modern metaphysicians. In this admirable perspicuity Descartes was imitated by his disciples Arnaud and Malebranche, especially the former. His unfinished posthumous treatise, the “Inquiry after Truth by Natural Reason,” is not carried farther than a partial development of the same leading principles of Cartesianism. There is consequently a great deal of apparent repetition in the works of Descartes, but such as on attentive consideration will show, not perhaps much real variance, but some new lights that had occurred to the author in the course of his reflections.[228] [227] Id. p. 121-212.