John Venn

John Venn (1834–1923) was an English logician and philosopher who spent his career at Gonville and Caius College, Cambridge. Ordained in the Church of England, he later gave up his clerical orders and devoted himself to logic and the moral sciences. The Logic of Chance (1866) set out a frequency theory of probability, and Symbolic Logic (1881) developed the work of George Boole. In an 1880 paper he introduced the overlapping circles now known as Venn diagrams. In later life he compiled, with his son, a vast register of Cambridge alumni, and he built a machine for bowling cricket balls.