Blaise Pascal

Blaise Pascal (June 19, 1623 - August 19, 1662) was a French mathematician, physicist, and philosopher. A child prodigy educated by his father, his early work was in the natural and applied sciences. In mathematics, he made significant contributions to projective geometry, probabilities, and combinatorial mathematics. In physics, he studied fluids, clarifying the concepts of pressure and vacuum by generalizing the work of Evangelista Torricelli. After a mystical experience in 1654, he abandoned his scientific work and devoted himself to philosophy and theology. From this period, two books are mostly remembered : Lettres provinciales and Pensées.

Mathematics
In 1654, Pascal published his Traité du triangle arithmétique ("Treatise on the Arithmetical Triangle") in which he describes a convenient tabular presentation for the binomial coefficients: Pascal's triangle. The same year, a friend interested in gambling posed a question that would open up a new mathematical field of enquiry. Suppose there are two players who want to finish a game early and want to divide the stakes fairly. How much should each player receive? Pascal corresponded with Pierre de Fermat on the subject, and the mathematical theory of probabilities was born. They introduced the notion of expected value, and their work on the calculus of probabilities laid the groundwork for Gottfried Leibniz's formulation of the infinitesimal calculus.