Frank Plumpton Ramsey

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Frank Plumpton Ramsey (born February 22, 1903 in Cambridge , † January 19, 1930 ) was a British mathematician and logician .

Live and act

Ramsey was born in Cambridge, where his father, also a mathematician, was President of Magdalene College . He attended college in Winchester before returning to Cambridge to study mathematics at Trinity College . He was named "Senior Wrangler" in the Tripos (highly competitive math exams) in 1923 , the highest award for a math student at Cambridge at the time.

Ramsey's superior intelligence impressed many Cambridge academics. He was well-read in various fields and was interested in almost everything. Politically, he was left-wing and (in the words of his wife) a “militant atheist ”. In a conversation with Charles Kay Ogden , he expressed his desire to learn German. Ogden gave him a dictionary, along with a German grammar and a difficult to understand philosophical treatise and said to him: “Use the grammar and the dictionary; come back and tell us what you think about it. ”About a week later he had not only learned German, but had objections to the theories in the treatise. He used his newly acquired ability to read Ludwig Wittgenstein's Tractatus Logico-Philosophicus , which he was just finishing in 1918.

The reading made a deep impression on him. He translated a large part of it into English and published a first review in the philosophical journal Mind . In 1923 he traveled to Austria for a short time and held discussions with Wittgenstein, who was working as a village teacher at the time. In 1924 another visit to Austria followed for a psychoanalysis with Theodor Reik in Vienna and further visits with Wittgenstein. From March to October 1924 Ramsey also took part in meetings of the Vienna Circle . Some philosophers believe that if Ramsey had lived longer, he would have achieved the same status as Wittgenstein publicly as a philosopher. Indeed, Ramsey's criticism influenced, in addition to discussions with Piero Sraffa , in which Ramsey was involved, Wittgenstein's late philosophy in the " Philosophical Investigations ". Further philosophical works by Ramsey deal with the character of natural laws and the philosophy of science .

Apparently torn between the events of the just ended First World War and under the impression of a genius like Wittgenstein, he wrote to his mother during this time: “We really live in a great time for thinking, with Einstein , Freud and Wittgenstein all alive , and all in Germany or Austria, those foes of civilization! "(German:" We really live in philosophically great times, with Einstein, Freud and Wittgenstein still alive among us, all in Germany and Austria, these enemies of civilization ") .

Back in England, at the young age of 21, he was appointed a Fellow at King's College , where he was Director of Studies in Mathematics.

His discussions with Wittgenstein also meant that he could considerably simplify the sentences of the monumental "Principia Mathematica" by Bertrand Russell and Alfred North Whitehead , which wanted to reduce all mathematics to logic: he underlined that logical sentences are tautologies in the sense Wittgensteins and pointed out that only logical and no semantic paradoxes need to be discussed. He showed that the axiom of reducibility they used was superfluous.

The two existential theorems, which were established by Ramsey in his work "On a problem of formal logic", acted as the initial spark for further work in the field of graph theory and combinatorics and are known as the Ramsey theorem. The corpus that emerged in combinatorics under the hand of Paul Erdős and others is called the Ramsey theory . He proved his theorem ( theorem of Ramsey ) only as an aid in his essay, in which he shows the decidability of the decision problem of a certain fragment ( Bernays-Schönfinkel-Ramsey class ) of first-order logic. The American logician Alonzo Church later proved that the general decision problem of first order logic is undecidable.

Ramsey, who was friends with John Maynard Keynes , also published two important economic papers. In 1927, in A contribution to the theory of taxation , he sets up the Ramsey rule , which is an important contribution to the theory of optimal taxation. In his work A mathematical theory of saving from 1928 he uses the calculus of variations to investigate how much an economy should invest instead of consume so that it continues to grow to the maximum in the future. This difficult work was admired by John Maynard Keynes and later by Paul Samuelson and is considered to be the starting point for “optimal accumulation” further developed by Tjalling Koopmans and David Cass . His methods (dynamic optimization) were just as important as the results.

Ramsey criticized Keynes' theory of probability as inductive logic so sharply that he abandoned it. In "Truth and Probability" he also gave a theory of the probability measure for how strongly someone is convinced of a view (decision theory).

On January 19, 1930, Frank Plumpton Ramsey died at the age of 26 as a result of an abdominal operation in which he became infected with hepatitis (he also had liver problems throughout his life). He had been married since 1925 and had two daughters - both of whom remained loyal to the Church despite Ramsey's atheism. His brother Michael (1904–1988), later Lord Ramsey, was Archbishop of Canterbury from 1961 to 1974 .

Works (selection)

  • The Foundations of mathematics and other logical essays , RB Braithwaite ed., London, Routledge and Keegan Paul 1931
    • German translation: Ramsey Basics: Treatises on philosophy, logic, mathematics and economics , Stuttgart, Frommann-Holzboog 1980
  • Philosophical papers , Mellor ed., Cambridge 1990
  • On truth , Kluwer 1991 (Rescher, Majer ed., Draft of a book)
  • Notes on philosophy, probability and mathematics , 1990, Naples (Gavalotti ed.)
  • Truth and probability , 1926
  • The Foundations of Mathematics , in: Proceedings of the London Mathematical Society S2 25/5, 338–384, also in: Ramsey / Braithwaite 1931.
  • Universals , Mind 1925
  • Facts and propositions , Aristotelian society suppl.volume 7, 1927, p. 153 (PDF file; 3.09 MB)
  • Knowledge (1929)
  • Theories (1929; PDF file; 1.07 MB)
  • General propositions and causality (1929)
  • A mathematical theory of saving , Economic Journal Vol. 38, 1928
  • A contribution to the theory of taxation , Economic Journal Vol. 37, 1927
  • On a problem of formal logic , Proceedings London mathematical society, Vol. 30, 1930, p. 264 (the work is from 1928)

literature

  • Keynes Frank Plumpton Ramsey , in: “Essays in biography”, 1933
  • Cheryl Misak: Frank Ramsey: A Sheer Excess of Powers , Oxford University Press, 2020

Web links

Individual evidence

  1. ^ Stadler, Friedrich: Studies on the Vienna Circle. Origin, Development and Effect of Logical Empiricism in Context. Suhrkamp, ​​Frankfurt am Main 1997, 900.
personal data
SURNAME Ramsey, Frank Plumpton
BRIEF DESCRIPTION British mathematician and logician
DATE OF BIRTH February 22, 1903
PLACE OF BIRTH Cambridge , England
DATE OF DEATH January 19, 1930