1911 Encyclopædia Britannica/Mersenne, Marin

MERSENNE, MARIN (1588–1648), French philosopher and mathematician, was born of peasant parents near Oizé (Sarthe) on the 8th of September 1588, and died in Paris on the 1st of September 1648. He was educated at the Jesuit College of La Flèche, where he was a fellow-pupil and friend of Descartes. In 1611 he joined the Minim Friars, and devoted himself to philosophic teaching in various convent schools. He settled eventually in Paris in 1620 at the convent of L’Annonciade. For the next four years he devoted himself entirely to philosophic and theological writing, and published Quaestions celeberrimae in Genesim (1623); L’Impiété des déistes (1624); La Vérité des sciences (1624). These works are characterized by wide scholarship and the narrowest theological orthodoxy. His greatest service to philosophy was his enthusiastic defence of Descartes, whose agent he was in Paris and whom he visited in exile in Holland. He submitted to various eminent Parisian thinkers a manuscript copy of the Meditations, and defended its orthodoxy against numerous clerical critics. In later life, he gave up speculative thought and turned to scientific research, especially in mathematics, physics and astronomy. Of his works in this connexion the best known is L’Harmonie universelle (1636), dealing with the theory of music and musical instruments.

Among his other works are: Euclidis elementorum libri, &c. (Paris, 1626); Universae geometriae synopsis (1644); Les Mécaniques de Galilée (Paris, 1634); Questions inouïes ou récréations des savants (1634); Questions théologiques, physiques, &c. (1634); Nouvelles découvertes de Galilée (1639); Cogitata physico-mathematica (1644).

See Baillet, Vie de Descartes (1691); Poté, Éloge de Mersenne (1816).