A French mathematician, philosopher, and pioneer of probability theory whose short life was rich with mathematical invention but whose name, ironically, is most familiar from its association with an array of numbers – Pascal's triangle – which he didn't discover (though he did important work on it). Educated by his father (after whom the limaçon of Pascal is named), Pascal showed his intellectual prowess early on by proving one of the most important theorems in projective geometry at the age of 16. Three years later he devised the world's second mechanical calculating machine (the first was made by Wilhelm Schickard in 1623) to help with his father's business; he sold about 50 of these "Pascalines," several of which survive. In 1654, he and Pierre de Fermat, in an exchange of correspondence, laid the foundation for the theory of probability. They considered the dice problem, already studied by Girolamo Cardano, and the problem of points also considered by Cardano and, around the same time, by Luca Pacioli and Niccoló Tartaglia. The dice problem asks how many times one can expect to throw a pair of dice before getting a double six; the problem of points asks how to divide the stakes if a game of dice is incomplete. Pascal and Fermat solved the problem of points for a two-player game but didn't develop powerful enough methods to solve it for three or more players.
In the same year, Pascal was almost killed in an incident in which the horses pulling his carriage bolted and the carriage was left hanging over a bridge above the river Seine. Though rescued unharmed, he shortly after converted to the rigorous Jansenist sect of the Catholic Church. His philosophical work Pensées, written between 1656 and 1658 contains his famous argument, often called Pascal's Wager, for belief in God. Having suffered poor health for most of his adult life, he died in great pain of cancer at the age of 39.
