Mersenne, Marin

MERSENNE, MARIN. - French scientist and theologian, b. at Oizé (Sarthe) on 8 Sept. 1588, d. at Paris on 1 Sept. 1648. After completing his studies at the College of La Flèche, he entered the Order of the Minims. The fame of his name is still today unjustly linked almost solely to his friendship with Descartes (v.). It should be noted in this regard that, when M. left the College of La Flèche, Descartes was 13 years old and that many of his principal works are earlier than the Discours de la méthode (1637). M., "le secrétaire général de l'Europe savante" of his century, as Haureau writes, is much more than Descartes's man and occupies his own place in the great scientific and intellectual revolution of the 17th century. In contact with all the best-known scientists and philosophers of the age, he served as a point of connection, of meeting, of understanding, often succeeding in overcoming the personal rivalries and disagreements, not always of a doctrinal character, among his friends and correspondents. From a group of scientists that he gathered around himself (E. Pascal, Mydorge, Hardy, Roberval, the abbé Chambon, Pailleur, Montholon) was born the Académie Parisienne, the first nucleus of what would become the Académie des Sciences. His ideal always remained that of founding an international Academy (under the patronage of the pope and of the Christian princes), which would bring together theologians, philosophers, jurists, physicists, chemists, etc. More than to the history of philosophy, his name belongs to that of science and of music, he having also been a distinguished musicologist.

He dealt in fact with ancient and modern music in its various aspects: nature of sound, art of singing, harmony, composition (Les préludes de l'harmonie universelle, Paris 1634; L'harmonie universelle, contenant la théorie et la pratique de la musique, 2 vols., ibid. 1636-37, where, among other things, he adopts the theory of the subjectivity of sensible qualities). He conducted research on musical instruments, planning the construction of portable organs; and his experiments on vibrating strings and on sounding reeds or tubes made it possible to discover and announce precise laws that for about three centuries have gone under his name.

The Quaestiones celeberrimae in Genesim (Paris 1625) treat questions of philosophy, astronomy, cosmology, music. In L'impiété des déistes et des plus subtils libertins découverte et réfutée par raison de philosophie et de théologie (2 vols., ibid. 1624) he refutes intellectual "libertinism" and especially Bruno ("cattivo autore," p. 364) and Charron (v.), and he combats skepticism still further in La vérité des sciences contre les sceptiques ou Pyrroniens (ibid. 1695), where, before Descartes, he has recourse to immediate evidence, demonstrating that the skeptics' doubt destroys itself, inasmuch as whoever doubts everything knows at least with certainty that he doubts (p. 204). He collects and reissues the principal works of the ancient mathematicians in the Synopsis mathematica (ibid. 1626; reprinted in 1644 under the title Universae geometriae mixtaeque mathematicae synopsis). Of the other writings, mention should be made of the translation of Galileo's mechanics (Les méchaniques de Galilée, ibid. 1634: with the great Italian scientist, of whom he was an admirer, M. maintained an active correspondence [A. Favaro, Amici e corrispondenti di Galileo, XXXVIII, Florence 1917; P. Tannery, Correspondance de M., so far 3 vols., Paris 1933, 1936, 1949, passim] and contributed largely to spreading and gaining acceptance for his doctrines in France).

As has been demonstrated by recent studies (Lenoble), M.'s scientific-theological activity must be placed within the "naissance du mécanisme." Among the philosophies of the 17th century - Aristotelianism and Cartesianism - there is a third, the naturalism of the Renaissance (Pomponazzi, Bruno, Cardano, Paracelsus [v.]), which is still founded on the old magical theme of the Soul of the world, with grave harm to religion and science. M., like Galileo and Roberval, combats magic and animism and establishes the new mechanism (different from that of Descartes), that is, "reads nature by the mathematical rule." Indeed, in L'«impiété» (p. 374) M. writes, again against Bruno, that he preferred to say "that there are in the world only contingent effects and that God is the universal principle acting in all things and that he keeps individual natures united, rather than introduce a universal soul." M., moreover, as a sincere believer, "grafts onto it the apologetic motive of the justification of the 'miracle' which, precisely because it is a derogation from the laws of nature, presupposes such laws, without which it would not exist; therefore, to save the natural law is to save the miracle. He is convinced that the new mechanistic physics is a surer guarantee of the law of nature than the Aristotelian one. Thus M. brings his contribution to the birth of modern or quantitative physics, as a description of phenomenal nature according to the mathematical rule, without claims to an apodictic explanation and without building metaphysical systems upon it. It is, at bottom, the scientific definition of "phenomenon," for which M.'s doctrine has rightly been called a "critical empiricism."

Michele Federico Sciacca