Frank P. Ramsey
He graduated as a Wrangler (the Cambridge terminology for one who obtains the first-class score on the final examination in mathematics). In 1924 he became a fellow of King's College at the age of only 21. He produced a prodigious amount of work in the areas of the logic, mathematics, economics and philosophy. He died at the age of 26, ending a promising career too early.
Ramsey's most celebrated contribution to mathematics is now known as Ramsey Theory, the branch of graph theory and combinatorics that deals with the idea that within a sufficiently large system, however disordered, there must be some order. 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).
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 an of fact (1928), Knowledge (1929), Theories (1929), and General propositions and causality (1929).