John Venn, FRS, FSA (4 August 1834 – 4 April 1923) was an English mathematician, logician and philosopher noted for introducing Venn diagrams, which are used in logic, set theory, probability, statistics, and computer science. In 1866, Venn published The Logic of Chance, a groundbreaking book which espoused the frequency theory of probability, arguing that probability should be determined by how often something is forecast to occur as opposed to "educated" assumptions. Venn then further developed George Boole's theories in the 1881 work Symbolic Logic, where he highlighted what would become known as Venn diagrams. Life and career John Venn was born on 4 August 1834 in Kingston upon Hull, Yorkshire, to Martha Sykes and Rev. Henry Venn, who was the rector of the parish of Drypool. His mother died when he was three years old. Venn was descended from a long line of church evangelicals, including his grandfather John Venn. Venn was brought up in a very strict atmosphere at home. His father Henry had played a significant part in the Evangelical movement and he was also the secretary of the Society for Missions to Africa and the East, establishing eight bishoprics overseas. His grandfather was pastor to William Wilberforce of the abolitionist movement, in Clapham. He began his education in London joining Sir Roger Cholmeley's School, now known as Highgate School, with his brother Henry in September 1846. He moved on to Islington Proprietary School and in October 1853, he went to Gonville and Caius College, Cambridge. In 1857, he obtained his degree in mathematics and became a fellow. In 1903 he was elected President of the College, a post he held until his death. He followed his family vocation and became an Anglican priest, ordained in 1859, serving first at the church in Cheshunt, Hertfordshire, and later in Mortlake, Surrey. In 1862, he returned to Cambridge as a lecturer in moral science, studying and teaching logic and probability theory, and, beginning around 1869, giving intercollegiate lectures. These duties led to his developing the diagram which would eventually bear his name. He built rare machines. A certain machine was meant to bowl cricket balls. The machine was so fascinating that when Australian cricketers were visiting Cambridge, the machines were used to entertain their arrival. The bowling machine that Venn built actually bowled out the top ranked player of the team four times consecutively. In 1868, he married Susanna