Stanisław Jaśkowski (22 April 1906, in
Warsaw – 16 November 1965, in Warsaw) was a Polish
logician who made important contributions to
proof theory
Proof theory is a major branchAccording to Wang (1981), pp. 3–4, proof theory is one of four domains mathematical logic, together with model theory, axiomatic set theory, and recursion theory. Jon Barwise, Barwise (1978) consists of four correspo ...
and
formal semantics. He was a student of
Jan Łukasiewicz and a member of the
Lwów–Warsaw School of Logic. Upon his death his name was added to the Genius Wall of Fame. He was the President (rector) of the
Nicolaus Copernicus University in
Toruń.
Jaśkowski is considered to be one of the founders of
natural deduction, which he discovered independently of
Gerhard Gentzen in the 1930s. Gentzen's approach initially became more popular with logicians because it could be used to prove the
cut-elimination theorem. However, Jaśkowski's is closer to the way that proofs are done in practice. He was also one of the first to propose a formal calculus of
inconsistency-tolerant (or paraconsistent) logic. Furthermore, Jaśkowski was a pioneer in the investigation of both
intuitionistic logic and
free logic
A free logic is a logic with fewer existential presuppositions than classical logic. Free logics may allow for terms that do not denote any object. Free logics may also allow models that have an empty domain. A free logic with the latter propert ...
.
Works
''On the Rules of Suppositions in Formal Logic''Studia Logica 1, 1934 pp. 5–32 (reprinted in: Storrs McCall (ed.), ''Polish Logic 1920-1939'', Oxford University Press, 1967 pp. 232–258
* ''Investigations into the System of Intuitionist Logic'' 1936 (translated in: Storrs McCall (ed.), ''Polish Logic 1920-1939'', Oxford University Press, 1967 pp. 259–263
* ''A propositional Calculus for Inconsistent Deductive Systems'' 1948 (reprinted in: Studia Logica, 24 1969, pp 143–157 and in: Logic and Logical Philosophy 7, 1999 pp. 35–56)
* ''On the Discussive Conjunction in the Propositional Calculus for Inconsistent Deductive Systems'' 1949 (reprinted in: Logic and Logical Philosophy 7, 1999 pp. 57–59)
* ''On Formulas in which no Individual Variable occurs more than Twice'', Journal of Symbolic Logic, 31, 1966, pp. 1–6)
; in Polish:
* ''O symetrii w zdobnictwie i przyrodzie - matematyczna teoria ornamentów'' (English title: ''On Symmetry in Art and Nature''), PWS, Warszawa, 1952 (book 168 pages)
* ''Matematyczna teoria ornamentów'' (English title: ''Mathematical Theory of Ornaments''), PWN, Warszawa, 1957 (book 100 pages)
References
*
*
* Jerzy Kotas, August Pieczkowski. ''Scientific works of Stanisław Jaśkowski'', Studia Logica 21, 1967, 7-15
External links
1906 births
1965 deaths
Writers from Warsaw
Polish logicians
Polish mathematicians
University of Warsaw alumni
Nicolaus Copernicus University in Toruń faculty
Paraconsistent logic
20th-century Polish philosophers
{{Poland-philosopher-stub