Pascal. Engraving of the French mathematician and philosopher Blaise Pascal (1623-1662). Educated by his father, Pascal was a child prodigy. At 16 he published a book on geometry, in which he deduced 400 propositions, and at 19 invented a calculating machine (seen here) that could add and subtract. Together with Fermat he founded probability theory, and on his own discovered the basis of hy- draulics. In 1654 he experienced a profound mystical experience after narrowly escaping death in a horse-drawn carriage. As a result he abandoned mathematics and retired to a strict convent to devote the rest of his short life to meditation and writing.