born June 19, 1623, Clermont-Ferrand, France
died Aug. 19, 1662, Paris
French mathematician, physicist, and religious philosopher.
The son of a mathematician, he was a child prodigy, earning the envy of René Descartes with an essay he wrote on conic sections in 1640. In the 1640s and '50s he made contributions to physics (formulating Pascal's law ) and mathematics (working on the arithmetic triangle, inventing a calculating machine, and contributing to the advance of differential calculus). For work done in his early years, he is regarded as the founder of the modern theory of probability. At the same time, he became increasingly involved with Jansenism . Les Provinciales were a series of letters defending Jansenism and attacking the Jesuit s. His great work of Christian apologetics, Apologie de la religion chrétienne, was never finished, but he put together most of his notes and fragments between 1657 and 1658; these were published posthumously as Pensées (1670). He returned to scientific work, contributing to the Élements de géométrie and publishing his findings on cycloid curves, but he soon returned to devotional life and spent his last years helping the poor. The pascal was named in his honour. See also Pascal's wager.