Blaise Pascal was a French mathematician, physicist, inventor and philosopher. A gifted mathematician from an early age, he made important contributions to projective geometry and, with Pierre de Fermat, helped establish the mathematical theory of probability. His experiments on atmospheric pressure and vacuums also contributed to the study of fluids; the SI unit of pressure, the pascal, was later named after him.

In the 1640s, Pascal designed a mechanical calculator, now known as the Pascaline, to assist with arithmetic. His later work increasingly focused on religion and philosophy, influenced by the Jansenist community associated with Port-Royal. He defended its members in the satirical and argumentative Provincial Letters.

Pascal’s unfinished notes on Christian belief were published after his death as Pensées. They include the argument commonly called Pascal’s Wager and remain an influential contribution to religious philosophy and French prose.