Mathematician, physicist, theologian, and man of letters, Pascal was born at Clermont-Ferand, in central France, where his father was a lawyer, magistrate, and tax commissioner. His mother died when he was three and, instead of hiring a tutor, his father educated all three children himself, teaching them history and science through games, and religion through reading the Bible. Etienne Pascal waited to teach the children geometry until they were old enough to appreciate it; but at age 11, young Blaise worked out some of Euclid's geometric propositions for himself.

In 1647, observing the difficulty his father was having with tax calculations, Pascal invented a calculating machine that used a series of rotating discs, a system that has been the basis of calculating machines up to modern times. Later Pascal invented the barometer, the hydraulic press, and the syringe. One of his discoveries, known in physics as Pascal's Law, states that when pressure is applied to any part of an enclosed liquid the pressure is distributed equally to all parts of the liquid. This principle is the foundation of modern hydraulics.

Until 1654, he spent his time between mathematics and the social round in Paris, but a mystical experience that year resulted in a a spiritual conversion and led him to join his sister who was a member of the Jansenist sect. Pascal defended Jansenist beliefs against attacks by the Jesuits in his Lettres Provinciales (1656-57). About 1660, Pascal began jotting down ideas for a case book of Christian truths (or manual of apologetics). He never went on to write the larger work, for he died in 1662, at age 39. His notes were later discovered and published as Pensees (thoughts) in 1659. The work is a classic of apologetics as well as literature.

In Pensees, Pascal makes the case for Christianity as against the rationalism of Descartes and the skepticism of Montaigne. For Pascal, God is to be known through faith in Jesus Christ. Faith does not come through reason, it is a gift from God. Man's need for God comes when he recognizes his misery apart from God and realizes that nothing else can satisfy that need. Although God is to be know by faith, Pascal maintains that the evidences for Christianity are great: the prophecies, the miracles, the witness of history, and the self-authentication of Scripture.

• Pensees (c. 1660, published 1669)