Jan Łukasiewicz | |
|---|---|
 Łukasiewicz in 1935 | |
| Born | 21 December 1878 |
| Died | 13 February 1956(1956-02-13) (aged 77) |
| Education | |
| Alma mater | Lemberg University |
| Philosophical work | |
| Era | 20th-century philosophy |
| Region | Western philosophy |
| School | Lwów–Warsaw school Analytical philosophy |
| Main interests | Philosophical logic,mathematical logic andhistory of logic |
| Notable ideas | Polish notation Łukasiewicz logic Łukasiewicz–Moisil algebra Reductive reasoning |
Jan Łukasiewicz (Polish:[ˈjanwukaˈɕɛvit͡ʂ]ⓘ; 21 December 1878 – 13 February 1956) was a Polishlogician andphilosopher who is best known forPolish notation andŁukasiewicz logic.[1] His work centred onphilosophical logic,mathematical logic andhistory of logic.[2] He thought innovatively about traditionalpropositional logic, the principle ofnon-contradiction and thelaw of excluded middle, offering one of the earliest systems ofmany-valued logic. Contemporary research onAristotelian logic also builds on innovative works by Łukasiewicz, which applied methods from modernlogic to the formalization ofAristotle'ssyllogistic.[3]
The Łukasiewicz approach was reinvigorated in the early 1970s in a series of papers byJohn Corcoran andTimothy Smiley that inform modern translations ofPrior Analytics by Robin Smith in 1989 andGisela Striker in 2009.[4] Łukasiewicz is regarded as one of the most important historians of logic.
He was born inLemberg inAustria-Hungary (nowLviv,Ukraine) and was the only child of Paweł Łukasiewicz, a captain in the Austrian army, and Leopoldina,née Holtzer, the daughter of a civil servant. His family wasRoman Catholic.[5]
He finished hisgymnasium studies in philology and in 1897 went on toUniversität Lemberg, where he studied philosophy and mathematics. He was a pupil of the philosopherKazimierz Twardowski.[6]
In 1902, he received a Doctor of Philosophy degree under the patronage of EmperorFranz Joseph I of Austria, who gave him a special doctoral ring with diamonds.[7]
He spent three years as a private teacher, and in 1905, he received a scholarship to complete his philosophy studies at theUniversity of Berlin and theUniversity of Louvain in Belgium.[7]
Łukasiewicz continued studying for hishabilitation qualification and in 1906 submitted his thesis to the University of Lemberg. That year, he was appointed a lecturer at the University of Lemberg, where he was eventually appointed Extraordinary Professor by Emperor Franz Joseph I. He taught there until theFirst World War.[7]
In 1915, he was invited to lecture as a full professor at theUniversity of Warsaw, which theGerman occupation authorities had reopened after it had been closed down by theTsarist government in the 19th century.[7]
In 1919, Łukasiewicz left the university to serve as Polish Minister of Religious Denominations and Public Education inPaderewski's government until 1920. Łukasiewicz led the development of a Polish curriculum replacing the Russian, German and Austrian curricula that had been used in partitioned Poland. The Łukasiewicz curriculum emphasized the early acquisition of logical and mathematical concepts.[citation needed]
In 1928, he married Regina Barwińska.[7]
He remained a professor at the University of Warsaw from 1920 until 1939, when the family house was destroyed by German bombs, and the university was closed by the German occupation. He had been a rector of the university twice during which Łukasiewicz andStanisław Leśniewski had founded theLwów–Warsaw school of logic, which was later made famous internationally byAlfred Tarski, who had been a student of Leśniewski.
During the start of theSecond World War, he worked at the WarsawUnderground University. After the German occupation authorities had closed the university, he earned a meager living in the Warsaw city archive. His friendship withHeinrich Scholz (German professor of mathematical logic) helped him, too, and it was Scholz who arranged for the Łukasiewicz family's passage to Germany in 1944 (Łukasiewicz was fearful of the Red Army advance). As it became increasingly clear that Germany would lose the war, Łukasiewicz and his wife tried to move toSwitzerland, but were unable to get permission from the German authorities. They thus spent the last months of the war inMünster, Germany. After the end of the war, unwilling to return to a Soviet-controlled Poland, they moved first to Belgium, where Łukasiewicz taught logic at a provisional Polish Scientific Institute.[7]
In February 1946, at the invitation of Irish political leaderÉamon de Valera (himself a mathematician by profession), Łukasiewicz and his wife relocated to Dublin, where they remained until his death there a decade later. In Ireland, he briefly served as Professor of Mathematical Logic at the Royal Irish Academy (a position created for him). His duties involved giving frequent public lectures.[7]
During this period, his bookElements of Mathematical Logic was published in English by Macmillan (1963, translated from Polish by Olgierd Wojtasiewicz).[8]
Jan Łukasiewicz died on 13 February 1956. He was buried inMount Jerome Cemetery, in Dublin. At the urging of the Armenian community in Poland, his remains were repatriated to Poland 66 years later. He was reburied on 22 November 2022 in Warsaw's OldPowązki Cemetery.[9]
From October to December 2022, the Royal Irish Academy in Dublin hosted an exhibition on his life and work.[10]
Łukasiewicz'spapers (post-1945) are held by theUniversity of Manchester Library.
A number of axiomatizations ofclassicalpropositional logic are due to Łukasiewicz. A particularly elegant axiomatization features a mere threeaxioms and is still invoked to the present day. He was a pioneer investigator ofmulti-valued logics; histhree-valued propositional calculus, introduced in 1917, was the first explicitly axiomatizednon-classicallogical calculus. He wrote on thephilosophy of science, and his approach to the making of scientific theories was similar to the thinking ofKarl Popper.
Łukasiewicz invented thePolish notation (named after his nationality) for thelogical connectives around 1920. A quotation from a paper by Jan Łukasiewicz in 1931[11][12] states how the notation was invented:
I came upon the idea of a parenthesis-free notation in 1924. I used that notation for the first time in my article Łukasiewicz (1), p. 610, footnote.
— Łukasiewicz 1970, p. 180, Footnote 3
The reference cited by Łukasiewicz, i.e., Łukasiewicz (1),[13] is apparently a lithographed report inPolish. The referring paper[14] by Łukasiewicz was reviewed byHenry A. Pogorzelski in theJournal of Symbolic Logic in 1965.[15]
In Łukasiewicz's 1951 book,Aristotle's Syllogistic from the Standpoint of Modern Formal Logic, he mentions that the principle of his notation was to write the functors before the arguments to avoid brackets (i.e., parentheses) and that he had employed his notation in his logical papers since 1929.[16] He then goes on to cite, as an example, a 1930 paper he wrote withAlfred Tarski on thesentential calculus.[17]
This notation is the root of the idea of therecursive stack, a last-in, first-out computer memory store proposed by several researchers includingTuring,Bauer andHamblin, and first implemented in 1957. In 1960, Łukasiewicz's notation concepts and stacks were used as the basis of theBurroughs B5000 computer designed byRobert S. Barton and his team atBurroughs Corporation inPasadena, California. The concepts also led to the design of the English Electric multi-programmedKDF9 computer system of 1963, which had two such hardware register stacks. A similar concept underlies thereverse Polish notation (RPN, a postfix notation) of theFriden EC-130 calculator and its successors, manyHewlett-Packard calculators, theLisp andForth programming languages, and thePostScript page description language.
In 2008, thePolish Information Processing Society established the Jan Łukasiewicz Award, to be presented to the most innovative Polish IT companies.[18]
From 1999 to 2004, the Department of Computer Science building at UCD was called the Łukasiewicz Building, until all campus buildings were renamed after the disciplines they housed.
His model ofthree-valued logic allowed for formulatingKleene's ternary logic and a meta-model of empiricism, mathematics and logic, i.e. senary logic.[19]
{{cite book}}:ISBN / Date incompatibility (help) (Reprinted byGarland Publishing in 1987,ISBN 0-8240-6924-2)published for the first time in 1961(included inŁukasiewicz 1970, pp. 110–128)
ContainsList of Publications by Jan Łukasiewicz, pp. 401–405
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