Stanislaw Lesniewski
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 Main Works and Selected Bibliography
 Documentation on Lesniewski and Other Links
 Papers on Lesniewski
A. Betti, Lukasiewicz and Lesniewski on Contradiction
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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.


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Stanislaw Lesniewski was born on March 28th (March 16th according to the Old Calendar), 1886 in Serpuchov , a town 100 km. from Moscow, Russia, the son of Izydor - a communications engineer - and Helena Paczewski and was baptised in St. Petersburg in the Church of St. Stanislav (at present it is a club, in Soyuza Pechatnikov ul. , 22). In 1896 he attended the realna School in Trojtskosawski (?), near Kiacht and Majmaczyn, in the far lands of Southern Siberia on the Mongolian borders, where his father was at that time working on the construction of the Trans-Siberian Railway . In 1899 he enrolled in the gymnasium of Irkutsk , on the banks of the Angara river, a tributary of Lake Bajkal. In 1903 he left school to take his leaving examination in 1904 as an external candidate. He received his education chiefly in German universities, studying Philosophy and Mathematics for 8 years "with breaks" . First he studied Philosophy in Leipzig from October 17th 1904 to April 30th 1906, where he lived in Braustrasse 3 c/o Rappmund, Braustrasse 4 c/o Pieper and Albertstrasse 16 c/o Stephan. He attended courses in Inorganic Chemistry and its Applications (with Beckmann), Systematic Human Anatomy (Doctrine of Bones and Articulations with Spalteholz and Muscles and Vessels with Fick); Social, Economic and Constitutional History of the Recent Past with Karl Lamprecht ) in the winter semester 1904/05. Then (summer semester, 1905) Psychology (with Wilhelm Wundt ), Institutions of Political Economics (with Buecher), and, in the winter semester of 1905/06, Theory of Knowledge as an Introduction to Philosophy with Volkelt. Then he went to Heidelberg and Zurich . He joined the Ludwig Maximilian University in Münich , at least from the summer semester of 1909. He lived there in Belgradstrasse 33/II and attended the courses of the neo-Kantian positivist Hans Cornelius. In the summer semester of 1909 he attended Cornelius' introductory courses in Logic and in the Theory of Knowledge, with particular attention to Kant , and Philosophy of Mathematics with Moritz Geiger (Exercises for advanced students). In the winter semester of 1909/10 Cornelius' courses in Philosophy (Exercises for advanced students), as well as Logic and Theory of Knowledge with Pfaender. Before or after going to Münich, he possibly went back to St. Petersburg, where he met (for the first time?) the renowned philosopher of law Leon Petrazycki . In the summer semester of 1910, wanting to write his doctorate under Kazimierz Twardowski's supervision, he finally arrived at the University of Lvov (now Lviv, Ukraine), which was then the capital of Galicia , the furthermost land on the Eastern border of the Austro-Hungarian Empire. Twardowski, a pupil of Franz Brentano, had come from Vienna in 1895 to take the chair of Philosophy in Lvov . At that time other brentanians were active in the Universities of the Empire, among others Alexius Meinong , Edmund Husserl , Carl Stumpf and Anton Marty. And as a matter of fact the book that Lesniewski carried with him on his arrival in Lvov was Marty's Untersuchungen zur Grundlegung der allgemeinen Grammatik und Sprachphilosophie (1908), which he would have liked to translate and never did, progressively dissuaded by the new perspectives of research in the Lvov milieu, where Lesniewski joined Twardowski's group of Ph.D. students (Tadeusz Kotarbinski , Kazimierz Ajdukiewicz , Zygmunt Zawirski and Tadeusz Czezowski ). It seems that Lesniewski completed his mathematical education in Lvov, taking an interest in logical paradoxes, Schroeder's algebra of logic, the theory of relations and probability theory. The first evidence we have of Lesniewski's scientific activity is his participation in the discussion of the lecture "Metaphysics: the History of its Name, Concept and Currents" given by Ignacy Halpern on October 28th 1910 at the Polish Psychological Society in Warsaw. In the same year Lesniewski wrote his first paper, "A Contribution to the Analysis of Existential Statements", which, following Twardowski's suggestions, he revised for publication in Przeglad filozoficzny (1911). Finally he submitted it as a doctoral dissertation under Twardowski's supervision obtaining the title of doctor in July 1912. In the Contribution Lesniewski introduced and perfectly mastered the language/metalanguage distinction which his pupil Tarski - who in his Concept of Truth in the Languages of Deductive Sciences (1933) founded modern formal semantics - is often said to have established. The paper, which is a very refined treatise, already sets forth all the features which were to be typical of Lesniewski's whole work: terminological accuracy, an obsession with clearness, the search for a language which was most suitable for science. On May 12th 1911 he delivered the lecture "The Problem of Existence in the Light of Grammatical Norms" at the Polish Psychological Society in Warsaw. He then went to Paris, where he finished his second paper, "An Attempt to prove the Ontological Principle of Contradiction", which was directed against Lukasiewicz's On the Principle of Contradiction in Aristotle (1910) and appeared in Przeglad filozoficzny in 1912. As Lesniewski himself wrote in On the Foundations of Mathematics (1927-31), his "synoptico-autobiographical" main work, Lukasiewicz's book "became a revelation for me in many respects and for the first time in my life I learned of the existence of the 'symbolic logic' of Bertrand Russell as well as his 'antinomy' regarding the 'class of classes which are not elements of themselves" (p. 181 [with changes]). However, the 'revelation' carried with itself a strong aversion to the discipline, which was overcome only some years later. On October 23rd 1911, he gave the lecture "The Problems of Contradictory Objects and the Theory of Language" at the Polish Psychological Society in Warsaw. In the summer semester of 1912 he gave two lectures (numbers 14 and 15 of a cycle of 25) on the principles of the Excluded Middle at the Little Philosophical Circle of the Academic Library of the University of Lvov. Of the six sittings for the discussions, the last two were dedicated to Lesniewski's lectures. In 1913 he sojourned in Sanremo (Italy) for a couple of months, where apart from revising and translating the previous two articles into Russian under the title Logical Studies, which he finished in January, he wrote two other papers in March, "A Criticism of the Logical Principle of the Excluded Middle", which was evidently prepared by the lectures, and "Is Truth only Eternal or is it both Eternal and Sempiternal? A Polemico-popular Sketch on the Theory of Creation", addressed against Kotarbinski's "The Problem of the Existence of the Future". He planned a review of Leon Chwistek's "The Principle of Contradiction in the Light of the more Recent inquiries of Bertrand Russell" (1912), but this review has never been found. At that time he promised Twardowski to review a book by the sociologist Florian Znaniecki (probably Humanism and Knowledge), but he found it - as anyone would expect from Lesniewski's standards of clear philosophical writing - incomprehensible, and gave up. Probably in the spring he married Zofia Prewysz-Kwinto. The "Criticism" was published in Przeglad filozoficzny, while "The Truth" was published in New Paths, a pedagogical review, since it was probably rejected by The Warsaw Weekly. On April 25th, he gave the lecture "The Problem of Creating the Truth" at the Polish Psychological Society in Warsaw. The 1911-13 papers chiefly concern Lesniewski's theory of truth and meaning, and should be seen as the first philosophical foundations of Ontology. After France and Italy he possibly went to St. Petersburg. It seems that in the 1913 telephone book of St. Petersburg he was registered as living in Prospekt Vladimirskij . As a matter of fact that street, as well as its prolungation (Prosp. Litejny), seemed to be a meeting spot for Poles living there, and was the location of the main Polish institutions. From the second half of 1913 Lesniewski moved to Warsaw, as a letter from Kotarbinski to Twardowski indicates. From October 1913 he led the Philosophy Session of the Polish Teachers' Circle in Warsaw (Nowe Tory). In November-December 1913 he gave the public lecture "Paradoxes of logic and mathematics" at the Polish Psychological Society in Warsaw. In January 1914, in Kimborciszki, near the Eastern border of Lithuania, where his wife's father had an estate, he elaborated his powerful and original solution of Russell's Paradox . He published it in the article "Is the Class of Classes subordinated to Themselves subordinated to Itself?" (Przeglad filozoficzny, 1914), with which he started broadening his research perspectives, introducing his concept of collective class and therefore the philosophical foundations of Mereology. On January 26th he gave the lecture "On a Property of all Classes" and on May 11th "A Contribution to the Criticism of the Theory of Sets" at the Polish Psychological Society in Warsaw. He then started writing a review of Benedykt Bornstein's "Philosophical Foundations of the Theory of Sets" (1914), which he finished in September 1914. In 1915 he left for Russia. Information about Lesniewski's decision to live in Russia can be traced back to the 1913 letter to Twardowski from Sanremo, when he wrote that he had the intention of moving there. As far as we know, he lived in Moscow from 1915, where he taught mathematics in at least two Polish schools (a 'koedukacyjnej' school and a middle school for girls) up to 1918. In Moscow he also carried on a lecturing activity which was agitational in character, on socialist themes. He dedicated the Russian years chiefly to the elaboration of Mereology. In 1916 he published Foundations of the General Theory of Sets I , which, written in a formal language, even if not yet symbolic, was the first system of Mereology. Lesniewski's Mereology was a fruitful and deeply original reply to Russell &Whitehead's Principia Mathematica  (1910), a work which he studied for years and still would have liked to translate in 1923. On September 18th (according to the Old Calendar) an advanced course was organised and Lesniewski delivered the inaugural speech. As a professor he gave lectures in logic. On September 26th he delivered the Memorial Lecture in honour of Wladyslaw Weryho "Work on Logic in Poland in the last Ten Years". On March 3rd 1916 he delivered the lecture "The Problem of a System of the Theory of Sets Free from Contradictions", on April 19th (in Russian) "Problems with Axioms and Basic Definitions of the Theory of Sets". In October 1916 Lesniewski was elected to the Polish Society of Teachers in Moscow. In 1917 he presented the speech "The Antinomies of Formal Sciences and Language". The lectures were not published in the review of the Mathematical Society in Moscow, probably because he presented himself as an amateur and because his concept of set was far too eccentric. He also gave lectures at the Polish Circle of the Scientific Friendly Society (Mutual Benefit) in Moscow in the cycle "Fundamental Problems of Contemporary Philosophy": "Relativism and Absolutism", "Theory of Knowledge or Metaphysics", "On the Way to the New Logic"; and at the Polish Democratic Club: "Philosophical Foundations of Marxism" (1918). In June 1918 he was already back in the independent Warsaw after World War I. On June 9th 1918 he gave the lecture "On a Theorem in the Field of the Theory of Relations". The diffidence towards mathematical logic, which Lesniewski encountered for the first time in Lukasiewicz's formal appendix to the book of 1910, disappeared in the years 1918-1923, when he learned to master the elements of the "Theory of Deduction". Tadeusz Kotarbinski, in his report on the activity of the Institute of Philosophy of the University of Warsaw for the period June 28 1918/June 25 1919, published in Przeglad Filozoficzny, wrote that Lesniewski as a member of the Institute participated in the session of Logic during which, in 21 sittings from August 4th 1918, the first chapter of Russell and Whitehead's Principia Mathematica was read and commented on.
In 1918 (December 14th) he submitted the works Problems of the General Theory of Sets, I (a version of his 1916 work or the work itself?) and "A Criticism of the Logical Principle of the Excluded Middle" as his habilitation dissertation in Logic and Philosophy of Mathematics to be evaluated by
Waclaw Sierpinski . From the document of evaluation written by the latter (1919) we know that from the summer of 1918 he was employed in the Department of Religion and High Schools of the Ministry of Education. Lesniewski asked Twardowski to support his candidature in Lvov, but the plan was contrasted by Mscislaw Wartenberg (see the Wartenberg's letter to Twardowski). In a letter dated 9.5.1919 Twardowski informed Lesniewski that the commission formed by Wartenberg, Sierpinski, Marcin Ernst (dean) and Twardowski himself had decided to admit him to the habilitation, but - on the basis of the difficulties Lesniewski would meet - he suggested defending the dissertation in Warsaw. Lesniewski expressed to Twardowski his desire to defend the dissertation in Lvov (see the Lesniewski's letter to Twardowski), but finally he did not succeed: in Warsaw, (July 2nd 1919), Twardowski announced on behalf of Wartenberg the latter's opposition to Lesniewski's habilitation (see the Twardowski's diaries). In the Academic Year 1919/20 Lesniewski got the Chair of Philosophy of Mathematics, which was created especially for him at the University of Warsaw, where Lukasiewicz was already working. Here the attitude of Twardowski's scholars who were not cultivating logical interests was hostile to him (see the Witwicki's letters to Twardowski). In Warsaw he joined the group of mathematicians interested in the foundations of mathematics, headed by Zygmunt Janiszewski and Stefan Mazurkiewicz (Warsaw School of Mathematics ).In 1920, following Leon Chwistek's suggestion, he started to operate with symbolic language instead of natural language and constructed the formal system of Ontology, whose copula was expressed by the Greek letter 'epsilon' which Lesniewski took from Giuseppe Peano . On January 3rd or 10th he gave the lecture "Foundations of Ontology" at the Polish Psychological Society in Warsaw and on March 10th 1921 the lecture "On the Degrees of Grammatical Functions". The kind of attitude Lesniewski developed towards formal logic in these years was attacked - although not directly - by Twardowski in his "Symbolomania i pragmatofobia" (1921). In it Twardowski seemed to criticize Lesniewski and Lukasiewicz - without quoting their names - for their shifting to positions which the master considered raving formalism (see the Halpern's letter). In 1922 Lesniewski started to systematize the most general of his theories, Protothetics, the system that was to be the most widely developed after his death. A great contribution to Protothetics was made by Tarski. In his doctoral dissertation (under Lesniewski) "On the Primitive Terms of Logistics" (1923) Tarski showed that Protothetics could be based on equivalence as its primitive term. On November 12th 1923 Lesniewski participated in the discussion of the lecture "Truth and Falsity of Definitions" presented by Kotarbinski and on December 8th 1924 in the discussion of the lecture by Lukasiewicz "On a Certain Way of Conceiving the Theory of Deduction". At the Polish Congress of Philosophy (23-28 September 1927) Lesniewski spoke about "Foundations of the Theory of Classes", "Foundations of Ontology", "Foundations of Logistics", i. e. the outlines of his system, which he started to present in the same year in On the Foundations of Mathematics. The latter's dedication reads "A philosophical apostate, but a grateful pupil, offers this work as a delayed jubilee tribute to his Esteemed and Beloved Professor of Philosophy, Dr. Kazimierz Twardowski". Twardowski in his letter of thanks suggested that the work be translated from Polish. The suggestion was never followed during his lifetime. In the Warsaw milieu Lesniewski encountered deep respect and esteem for his work. Apart from the collaboration with Kotarbinski, who wrote that his reism found its logico-formal tools in Ontology, there was some mutual influence between Lesniewski and Lukasiewicz. However, his logic on the whole was never accepted as a standard, not even among Polish logicians. Lukasiewicz and Lesniewski trained eminent logicians, such as - apart from Tarski - Boleslaw Sobocinski, Stanislaw Jaskowski, Jerzy Slupecki, Alfred Lindenbaum and others. In 1928 a conflict between Cracow (which favoured Chwistek) and Warsaw logicians (who supported Tarski) for the new Chair of Logic at the Faculty of Physico-Mathematical Sciences of the University of Lvov arose. Twardowski - mainly following Lesniewski's counseling - took a negative position towards Chwistek, but the latter was finally preferred because of Bertrand Russell's support. On February 18th 1928 Lesniewski participated in the discussion on Lukasiewicz's lecture "On Definitions in the Theory of Deduction". On March 22nd 1930 "On the Foundations of Ontology", Warsaw Scientific Society, Section of Physico-Mathematical Sciences. Around 1935 Lesniewski was working on a dissertation about polivalent logic - that he probably never finished (see the Letter to Twardowski). In 1936 he was granted full professorship. From March to May 1936 he travelled abroad (Vienna, Dresden, Berlin, Leipzig, Münich, Nuremberg). Lesniewski's negative opinion regarding many-valued logic may be observed in his participation in the discussion on the lecture by Lukasiewicz "Genesis of Three-valued Logic" (1938), in which he strongly attacked Lukasiewicz's views. Lesniewski died of a thyroid cancer in Warsaw, on May 13th 1939.
- Other sources -

Czeslaw Lejewski's Ricordando Stanislaw Lesniewski, Centro Studi per la Filosofia Mitteleuropea, Trento 1989.
Letters from the Lesniewski-Twardowski correspondence
Conference reports from Ruch Filozoficzny
Photocopies of certificates from the German Universities of Leipzig and Münich; information from Prof. Solonin, anonymous transcriptions from a CV and official declarations, transcriptions from Sierpinski's report on Lesniewski's habilitation application, all kindly trasmitted provided by Jan Wolenski.

Large excerpts from the text above has been unauthorizedly translated into German without crediting the source by Uwe Wiedemann in In this disclaimer you find more on this.
Main Works (translated into English)


Selected Bibliography

Documentation on Lesniewski

 From Kazimierz Twardowski's Correspondence and Diaries

 From Lukasiewicz'Diary

 The Complete and Detailed List of Lesniewski's Letters to Kazimierz Twardowski

Other links

 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!

 New Releases and Used&Rare Books: Lesniewski

New and out-of-print books at Amazon

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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