Frank P. Ramsey - Work

Work

In 1927 Ramsey published the influential article Facts and Propositions, in which he proposed what is sometimes described as a redundancy theory of truth.

One of the theorems proved by Ramsey in his 1928 paper On a problem of formal logic now bears his name (Ramsey's theorem). While this theorem is the work Ramsey is probably best remembered for, he only proved it in passing, as a minor lemma along the way to his true goal in the paper, solving a special case of the decision problem for first-order logic, namely the decidability of (what is now called) Bernays–Schönfinkel–Ramsey class of first-order logic, as well as a characterization of the spectrum of sentences in this fragment of logic. Alonzo Church would go on to show that the general case of the decision problem for first-order logic is unsolvable (see Church's theorem). A great amount of later work in mathematics was fruitfully developed out of the ostensibly minor lemma, which turned out to be an important early result in combinatorics, supporting the idea that within some sufficiently large systems, however disordered, there must be some order. So fruitful, in fact, was Ramsey's theorem that today there is an entire branch of mathematics, known as Ramsey theory, which is dedicated to studying similar results.

His philosophical works included Universals (1925), Facts and propositions (1927), Universals of law and of fact (1928), Knowledge (1929), Theories (1929), On Truth (1929), and General propositions and causality (1929). Wittgenstein mentions him in the introduction to his Philosophical Investigations as an influence.