MERSENNE, mer-sen', Marin (1588-1648), French philosopher, theologian, and scientist, who served as a focal point of French and European scientific thought at a critical stage in its development. Mersenne corresponded or was personally acquainted with Descartes, Pierre Gassendi, Galileo, Thomas Hobbes, and Pascal. He was instrumental in opening lines of communication among scientists at a time when formal institutions for such a task scarcely existed, and he personally undertook the publication or translation of fundamental scientific treatises.

Mersenne was born at Oizé, France, on Sept. 8, 1588, and he studied at the Jesuit college in La Flèche. He joined the Minim friars and lived at their convent in Paris from 1619 until his death there on Sept. 1, 1648.

Mersenne's philosophical and scientific stance was shaped by his desire to uphold both Catholic orthodoxy and the new mechanical conception of nature against the twin menances of Renaissance naturalism, which maintained a magical interpretation of the world, and skepticism, which rejected the very possibility of attaining secure knowledge. Although he denied that the essence of things could even be known, he believed that scientists must seek experimental and quantitative precision in describing natural phenomena.

Mersennes's own voluminous scientific writings were on mathematics, music, acoustics, optics, and mechanics, and he discovered quantitative laws in these areas. He investigated pitch and vibrating strings and established that sound intensity is inversely proportional to the distance from its source. Despite these contributions, Mersenne is remembered principally as an "intelligencer" - a man who facilitated the cross-fertilization of the finest European minds of his age.

University of Wisconsin - Madison