Frank Plumpton Ramsey (February 22, 1903 - January 19, 1930) was a British mathematician and logician.
Ramsey was born in Cambridge where his father was President of Magdalene College. He was educated at Winchester College before returning to Cambridge to study mathematics at Trinity College.
He graduated as a Wrangler (the Cambridge term for one who obtains the first-class score on the final examination in mathematics).
Ramsey's intelligence was remarkable, and impressed many academics at Cambridge. He was well-read in a wide array of fields, having an interest in almost anything. In politics, he had left-wing leanings; and in religion he was, according to his wife, "a militant atheist". In one of his conversations with C. K. Ogden, he expressed his desire to learn German. Ogden gave him a grammar, a dictionary, and an abstruse psychological treatise and told him: "Use the grammar and use the dictionary and come and tell us what you think." About a week later, Ramsey had not only learnt the language, but had also come up with objections to the theory advanced in the book. He later used his acquisition to read Ludwig Wittgenstein's Tractatus Logico-Philosophicus. This impressed him deeply, and in 1923 he travelled to Austria to discuss it with Wittgenstein, who was then working as a teacher in a small village.
Back in England, in 1924 he became a fellow of King's College at the young age of 21. He produced a prodigious amount of work in the areas of the logic, mathematics, economics and the philosophy of those three disciplines. Unfortunately suffering from chronic liver problems, he contracted jaundice after an abdominal operation and died at the age of 26, ending a highly promising career too early.
One of the theorems proved by Ramsey in his 1930 paper On a problem of formal logic, which sparked the growth in this field, now bears his name (see Ramsey's theorem). It was an important early result in combinatorics, supporting the idea that within some sufficiently large systems, however disordered, there must be some order.
Further Ramsey, a good friend of economist John Maynard Keynes, published A contribution to the theory of taxation and A mathematical theory of saving. Keynes's work on probability stimulated Ramsey to develop arguments for subjective probability (Bayesian probability). As with the similar development by Bruno de Finetti the work only became well known in the 1950s.
His philosophical works included Universals (1925), Facts and propositions (1927), Universals of law and of fact (1928), Knowledge (1929), Theories (1929), and General propositions and causality (1929).
Frank Ramsey's younger brother, Arthur Michael Ramsey, was Archbishop of Canterbury from 1961 to 1974.