GASSEN DI, PE rEa, an eminent French philosopher, was born at Chantersier in Provence, in 1592. After giv ing very premature indications of his talents, which he did before he had reached his fifth year, he was sent to school at Digne, where he made rapid progress in the Latin lan guage, and acquired a decided pre•cminence among his schoolfellows. He was next sent to study philosophy at Aix, and when he had continued there two years, he re turned to his father's house, with the view of prosecuting his studies in retirement. A vacancy, however, having taken place at Digne, he was invited, at the early age of sixteen years, to teach rhetoric in that city ; and lie had scarcely filled this situation for three years, when he was appointed to the vacant chair of philosophy in the universi ty of Aix. The authority of Aristotle was still acknow ledged in almost all the public schools of France, and it re quired no ordinary boldness to call in question his philoso phical system. Gassendi, however, did not scruple to ex pose the errors of that great master, in the indirect form of paradoxical problems, which he published under the title of Exereitationes Paradzoiett adversus ?ristotelem. This work obtained for Gassendi the particular friendship of Nicholas Peiresc, president of the university of Aix, who succeeded, by the assistance of Joseph Walter, prior of Vallette, in procuring for him a canonry in the cathedral church of Digne, where he was admitted to the degree of doctor in divinity, and appointed rector of the church. This new situation, which enabled him to resign his chair at Aix, allowed Gassendi the uncontrolled management of his time. He composed a second book of his Exercitationes Parado•ie,e, for the purpose of pointing out the absurdity of the Aristotelian logic, and intended to pursue the subject to a much greater extent, but he was violently assailed by the powerful adherents of the ancient sage, and he con sidered it prudent to abstain from any farther attacks upon the Aristotelian system.
In the year 1628, Gassendi travelled into Holland, in or der to make himself acquainted with the philosophers of that country ; and during his visit, he composed an apology for his friend the learned Mersennus, in answer to the at tack of Robert Fludd on the subject of the Mosaic philoso phy. Upon his return to Digne, he resumed with great diligence his astronomical studies. He had the good for tune of being the first that observed a transit of Mercury over the sun's disc. This happened on the 7th of Novem ber 1631, the transit having been calculated by Kepler. In the year 1641, Gassendi was called by a lawsuit to Paris, and gained the acquaintance and esteem of the distinguish ed characters of that metropolis, and particularly of the Cardinal Richelieu, and his brother the Cardinal of Lyons. He had long preserved an intimacy with the great Des cartes; but a circumstance now occurred, which for a long time interrupted their friendship. In the year 1629, the singular phenomenon of two parhelia had been seen at Rome, and Gassendi published a dissertation on the sub ject. Descartes, in his Treatise on Meteors, described the same phenomenon, but forgot to make any reference to the dissertation of his friend. Gassendi chagrined at this ne glect, and probably not uninfluenced by a secret jealousy of Descartes' fame, attacked the philosophical system of his friend, in a work entitled, Disquisitio Metaphysica seu Du bitationes, &c. which was put into Descartes' hands by their
mutual friend Mersennus. Descartes replied to the objec tions of Gassendi, which he has published with his own answers, under the head of the Sixth objection in his Medi tations. In 1643, Gassendi composed his Instantix, as a reply to the answer of Descartes, and circulated it in MS. in Paris, before it was sent to M. Sorbierc to be printed at Amsterdam. This circumstance widened the breach be tween the two philosophers, which was still farther increas ed by their respective friends. In 1645, Descartes wrote a reply to Gassendi's Instantix ; but the differences between these philosophers IA ere now on the eve of being adjusted. The Abbe D'Estrees, afterwards archbishop of Laon and a Cardinal, lamented the dissentions which had so long sepa 1 ated these distinguished philosophers, and resolved to use all his influence in reconciling them. He invited a large par ty of their friends, among whom were Mersennus, Roberval, and the Abbe Marolles, to meet the two philosophers at a public dinner. Gassendi was prevented by an illness from attending ; but so anxious was the Abbe to effect his pur pose, that he took the company to Gassendi's apartments, where he and Descartes made mutual apologies for their conduct, and declared that their friendship should not again be interrupted by any difference of sentiment. By the in terest of the Cardinal of Lyons, Gassendi was, in 1645, ap pointed regius professor of mathematics at Paris. He read lectures on astronomy to crowded audiences, and added greatly to the reputation which he had formerly acquired. His constitution had now suffered from the severity of his studies, and having caught a cold, which occasioned an in flammation in his lungs, he was compelled, in 1647, to re turn to Digne for the recovery of his health. His native air produced a considerable amelioration in his strength, and he was able to return to Paris in 1653. He now pub lished his lives of Peiresc, Copernicus, Tycho Brahe, Put- bacillus, and Regiomontanus ; and forgetting the weakness of his constitution, his astronomical studies brought back his former disorder, of which he died in 1655, in the 63d year of his age. A short time before he breathed his last, he is said to have laid his hand on his heart, and feeling the languor of its pulsation, he said, " See how frail is the life of man !" Gassendi was intimately acquainted with the most distinguished characters of his age. His library and philosophical apparatus were purchased by the Emperor Ferdinand III. and deposited in the imperial library at Vi enna. His works and MSS. were collected and published after his death in 6 volumes folio by Sorbiere in 1658. They contain the philosophy and life of Epicurus ; the philosophy of Gassendi ; his astronomical works ; the lives of Peiresc, Copernicus, &c. ; a refutation of the meditations of Descartes' epistles ; a tract on the theory of music ; and other treatises. See I3ougerelle's Vie de Gassendi, Paris, 1737 ; and Baillet's Vie de Descartes, passim.