Blaise Pascal

At sixteen Pascal wrote a treatise on conic sections so accomplished that Descartes refused to believe a boy had written it. At nineteen he built a calculating machine – the Pascaline – to spare his father, a tax official, the endless columns of figures. Through letters with Pierre de Fermat about how to divide the stake in an interrupted game of chance, he founded the theory of probability. Few mathematicians of his century were more gifted.

On the night of 23 November 1654 something happened to him that he could not explain by science. He wrote it on a scrap of parchment in a single word – FIRE – and a line: "God of Abraham, God of Isaac, God of Jacob, not of the philosophers and the scholars." He sewed the sheet into the lining of his coat and wore it over his heart until he died; it was found only afterward. From then on he wrote the Pensées, a scattered, unfinished anatomy of the human creature swinging between wretchedness and greatness. Man is a thinking reed, the weakest thing in nature, yet a reed that thinks; he flees himself into diversion so as not to hear the silence of the infinite spaces that terrified him.

His wager is addressed to a gambler rather than a logician: if reason can prove neither God's existence nor his absence, you are already betting with the way you live, and the prudent bet is on eternity. His deeper claim is about knowledge itself – "the heart has its reasons, which reason does not know." We do not prove first principles; we feel them, and faith for Pascal belongs to the order of the heart rather than the conclusion of a proof. It is the Christian answer given from inside the scientific revolution, by one of its own architects. He died at thirty-nine, worn out by illness.