Named for the French philosopher and scientist Pierre Gassendi (1592–1655). Originally trained in theology, he came under the influence of the mathematician-theologian Mersenne. On 1631 Nov. 7 he made the first known observation of a transit of Mercury, thereby confirming the work of Kepler {see planet  (1134)}. As a philosopher, he revived Epicureanism as a substitute for Aristotelianism. At Mersenne’s request, he refuted Descartes’ {see planet  (3587)} Meditations in his Disquisitio Metaphysica (1644). In his great Syntagma Philosophicum, finally published as part of his opera omnia in 1658, he rejected the innate ideas of Descartes and favored the senses as the primary sources of knowledge. (M 31025) _ _.