Philosopher and logician, Lesniewski belonged to the first generation of the Lvov-Warsaw School founded by Kazimierz Twardowski , and is one of the most remarkable scientific personalities in the history of logic. Together with Jan Lukasiewicz and Alfred Tarski , his sole doctoral pupil, he formed the troika which in the 20s-30s of this century made the University of Warsaw perhaps the most important research centre in the world for formal logic. In his mature phase of activity he created a nominalistic system of foundations of mathematics composed of three formal theories of rare power and elegance: Protothetics , the 'theory of first sentences', Ontology, a 'modernized traditional logic', or a calculus of names based on the copula is, and Mereology, the 'theory of parts - mere - and wholes', i.e . the theory of collective classes with which his name is mostly associated. Lesniewski's thought underwent alternate fortunes. It was impressively popular in logical centres and circles which made an orthodoxy of his ideas, but such ideas were completely neglected far from those circles. Lesniewski's work was progressively pervaded by his increasing and maniacal perfectionism, which prevented him from publishing a great deal of results. This perfectionism also led him to firmly reject in public his early 'philosophico-grammatical' writings of 1911-1913. Lesniewski was a leading personality in the Lvov-Warsaw School, and immensely influential. The extreme sharpness of his criticism, which was awe-inspiring without comparison, joined his striving for the most possible rigour and exactness, revealing itself in his symbolism, which is the most accurate and clear - though highly complicated - formal writing that ever existed. He wrote in Polish and German.
From Kazimierz Twardowski's Correspondence and Diaries
From Lukasiewicz'Diary
The Complete and Detailed List of Lesniewski's Letters to Kazimierz Twardowski
A short presentation of Lesniewski's System of the Foundations of Mathematics
A. Betti, Logica ed esistenza in Stanislaw Lesniewski , tesi di laurea presentata all'Univ. di Firenze, rel. il prof. Ettore Casari, a.a. 1994/1995.
A short presentation of Lesniewski's argumentation against universals
The most important philosophical ideas of Lesniewski's thought, explained by quotations taken from his works. Follow the links!
Stanislaw J. Surma - Jan Szrednicki (eds.) Stanislaw Lesniewski - Collected Works (2 voll.) , Kluwer Academic Publishers, 1991 Zbigniew Stachniak (ed.), S. Lesniewski's Lecture Notes in Logic , Kluwer Academic Publishers, 1986
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