In the Winter-Summer 2022 edition of the Paraconsistent Newsletter we have: - latest papers and books about paraconsistent logic - videos of interest for paraconistentists - interview with Max Urchs - forthcoming events for paraconistentists https://www.paraconsistency.org/2022winter-summer
In the part events of this edition of the paraconsistent newsletter is announced the 6th edition of the Word Congress on Paraconsistency (WCP6) that will take place at the University Nicolaus Copernicus in Torun, Poland 5-8 September 2022. The deadline to submit an abstract is April 30. I am very glad that Marek Nasieniewski, main organizer of the event, took the initiative to organize WCP6, with the full support of the current head of the Department of Logic of this University (yes there are universities with a department of logic !), Tomasz Jarmuzek, also a long time friend. The University Nicolaus Copernicus is where the logician Stanisław Jaśkowski was working (he was also at some point the rector of this University). WCP6 is also the Second Stanisław Jaśkowski Memorial Symposium, Toruń The first took place in 1998 in Torun to celebrate Jaśkowski's first paper on Discussive Logic, considered as a fundamental step in the history of paraconsistent logic. The interview of this edition of the newsletter is with Max Urchs, one of the keynote speakers of WCP6, who worked in Torun in the 1970s. We were both colleagues at the Department of Logic of the University of Wroclaw in 1990s. In 1993 we went together with his cas (together with Andrew Wisniewskli, one of the best specialists of Erotetic Logic), to Prague to take part in the "Logica" meeting, crossing Bohemia. The latest edition of the WCP was in India in 2015. I organized it jointly with my colleague Mihir Chakarborty from Kolkata. I also was the co-organizer of WCP3 in Toulouse France in 2003, jointly with Walter Carnielli and Andreas Herzig. WCP1 took place in Ghent in 1997. It was the initiative of Graham Priest. At this time he was still working in Australia but decided to organize the event in Belgium with his friend Diderik Batens (three people took part in all WCPs: Diderik Batens, Walter Carnielli and myself) because he thought that not so many people would come to Australia. Then I proposed to organize WCP2 in Brazil in 1999, for the 70th birthday of Newton da Costa (born in 1929). The event was organized by my colleagues from Campinas: Itala D'Ottaviano, Walter Carnielli, Marcelo Coniglio, with the support of their students. It was delayed by one year. It took place May 8-12, 2000. In 2000 and 2001. I was working at Stanford University in California but came for the event. Before that, I succeeded in convincing my colleagues to organize the event on the beach, rather than at the campus of UNICAMP. I got the support of João Marcos, at the time a pos-graduated student at UNICAMP. With his car we drove the littoral during a couple days to find a good location. We chose Juquehy beach and the event was organized at Juqehy Praia Hotel https://juquehypraiahotel.com.br/ Everybody enjoyed it very much, according to Graham Priest,it was the best event he ever took part in. I think the success of an event depends 50% on its location. Since I am organizing events I have always looked for a good location. I have organized events at the American University of Beirut in Lebanon, Easter Island, Istanbul University, Lateran Pontifical University, Montreux, Switzerland, Xi'an, the ancient capital of China, the Orthodox Academy of Crete ... I have organized many events because I think research is a collective enterprise and cooperation between people is fundamental. This does not dismiss in any sense the merit of someone like Einstein. But Einstein did not invent non-Euclidean geometry. In logic. The two most famous logicians of the 20th century, Tarski and Göde,l on the basis on which I created the World Logic day in 2919: https://www.logica-universalis.org/wld4 were certainly both geniuses but Gödel grew up in the Hilbert-Bernays School and Tarski in the Lvov-Warsaw School: The Lvov-Warsaw School. Past and Present https://link.springer.com/book/10.1007/978-3-319-65430-0 (This book includes a paper about Jaskowsi) I started to work on paraconsistent logic in 1989, when I was a pos-graduted student of philosophy at the Sorbone, University of Paris 1, and of mathematics at Denis Diderot University (Paris 7). I discovered by chance an interview with Newton da Costa in the Lacanian magazine "L'âne" (the donkey.) about paraconsistent logic as the logic of the unconscious. I got interested in the topic because I wanted to understand the basis of reasoning, of logic. That's why I decided to study logical systems challenging the principle of non-contradiction. I did my master thesis (1990) on mathematical logic about the logic C1 of Newton da Costa, presenting a new version of its semantics, a sequent calculus for it and the corresponding cut-elimination theorem (I studied proof-theory with Jean-Yves Girard). Then I did a PhD on mathematical logic on "universal logic" (1995), a expression I put forward to develop a general theory of logical structures with no axioms, inspired by what Garret Birkhood did with "universal algebra" for algebraic systems. I don't know if there are some "laws of thoughts'". According to Boole the basic law of thought is square x is identical to x, from which he derives the principle of non-contradcition, see the paper: "Is the Principle of Contradiction a Consequence of x 2=x ?"" http://www.jyb-logic.org/BOO But I believe there is not one unique system of logic that describes human reasoning and its understanding of reality. That's why I think it is worth developing a general theory of all kinds of logical systems, including those in which the principle of non-contradiction is not valid, or the law of identity or excluded middle, transitivity, monotonicity, etc . I defend the idea of "axiomatic emptiness": "What is a logic? Towards axiomatic emptiness" https://jyb-logic.org/papers/what%20is%20a%20logic%20-%20towards%20axiomatic%20emptiness%20-%20beziau.pdf Although universal logic has been my main focus since then, I always continued to work on paraconsistent logic (and also on other non classical logics, different philosophical topics, semiotics, etc). In paraconsistent logic one of my main contributions was the discovery that there is a paraconsistent negation in the modal logic S5 and that therefore S5 is a paraconsistent logic (as well as first-order classical logic, considering Wajsberg theorem). I first built a logic I called "Z" inspired by Jaskowski's discussive logic. The negation of a proposition is false according to a group of people iff everybody of the group agrees that the proposition is true. For example if in a group of people everybody agrees that "The earth is flat" is true, then "The earth is not flat" is false according to this group of people. But if there is at least one who does not agree, then "The earth is not flat" is also true according to this same group of people, which therefore accepts to have a given proposition and its negation both true: “The paraconsistent logic Z - A possible solution to Jaskowski's problem”, Logic and Logical Philosophy, 15 (2006), pp.99-111 https://www.jyb-logic.org/Beziau_LLP_cor.pdf The content of this paper was first presented on a talk at the frist Stanisław Jaśkowski Memorial Symposium in Toruń in 1998.Poland This logic used only classical conjunctions, disjunction and implication and a paraconsistent negation semantically defined by a possible world semantics (this is why I decided to call it "Z", by reference to LeibniZ) . Then a friend of mine, Claudio Pizzi showed me that in Z it is possible to define necessity and classical negation, so at the end Z = S5. If we consider S5 as it is generally presented, the paraconsistent negation is the classical negation of necessity not box. “The Contingency of Possibility”, Principia, vol.20 n.1 (2016), pp.99-115. https://periodicos.ufsc.br/index.php/principia/article/view/1808-1711.2016v20n1p99/32670 So what I did with Z is a new formulation of S5 (both semantically and proof-theoretically) starting with this sole unary operator, not using necessity, possibility or classical negation. Routley (with Montgomery in the 1960s) started with the conjunction of diamond and not box, they called "contingency". This is very interesting from a philosophical point of view because this contingency operator is the usual sense of the word "possible" in natural language: something which is possible ... but not necessary! I met Richard Routley (then Sylvan) the first and last time in 1994 when he was visiting Newton da Costa in São Paulo with Graham Priest. I gave to him the draft of my first paper on universal logic, "Universal Logic": https://www.jyb-logic.org/papers/LogicaYB94%20-%20Beziau.pdf The following day he gave it back to me with some annotations and told me that he will speak about it in the forthcoming second volume of "Relevant Logics and Their Rivals", but not long after, back to Australia he died. I started the Paraconsistent Newsletter in 2006, inspired by a paper by Sylvan where he was speaking about the importance of a newsletter for relevant logic. I met Bob Meyer at the meeting of the Society for Exact Philosophy in Montreal in 1997 and explained to him the results about Z/S5, asking if someone had already done a similar work, he told me he never heard about such a thing. This paraconsistent negation has good properties, in particular it is self-extensional, i.e. it obeys the replacement theorem, by contrast to most of paraconsistent negations (C1, Asenjo-Priest three-valued logic, etc.) as shown here: “Idempotent full paraconsistent negations are not algebraizable”, Notre Dame Journal of Formal Logic, 39 (1998), pp.135-139. https://www.jyb-logic.org/idempotent.pdf When I was working with Tel-Aviv in 1995-96 with Arnon Avron within the Marie-Curie GeTFun project led by João Marcos and Carlos Caleiro http://sqig.math.ist.utl.pt/GeTFun I asked Arnon if it would be possible to have a self-extensional logic three-valued paraconsistent logic with a standard implication and the result is no! : A.Avron and J.-Y.Beziau, “Self-extensional three-valued paraconsistent logics have no implication”, Logic Journal of the IGPL, Volume 25, Issue 2 (April 2017), pp.183-194. https://academic.oup.com/jigpal/article-abstract/25/2/183/2739325/Self-extensional-three-valued-paraconsistent?redirectedFrom=fulltext&login=false I then asked him about such a situation for four-valued matrix semantics, and later on he published the paper, giving a positive answer to the question: "The Normal and Self-extensional Extension of Dunn–Belnap Logic" https://link.springer.com/article/10.1007/s11787-020-00254-1 Arnon Avroin will also be a keynote speaker of WCP6 Coming back to S5, it has not only good formal properties but the paraconsistent negation of Z has a good intuitive motivation / interpretation, as shown by the reconstruction of S5 through Z. So at the end I think S5 is one of the best paraconsistent logic ! (it has a paracomplete negation too, not possible). I also worked on the fundamental philosophical aspects of paraconsistent logic, may main contributions are the two following papers "Cats that are not cats - Towards a natural philosophy of paraconsistency" http://www.jyb-logic.org/CATS "Round Squares are no Contradictions" http://www.jyb-logic.org/ROS Jean-Yves Beziau Creator and Editor of the Paraconsistent Newsletter Paraconsistent Logician and Artist https://sites.google.com/view/miaou-rio/jyb > -- LOGICA-L Lista acadêmica brasileira dos profissionais e estudantes da área de Lógica <logica-l@dimap.ufrn.br> --- Você está recebendo esta mensagem porque se inscreveu no grupo "LOGICA-L" dos Grupos do Google. Para cancelar inscrição nesse grupo e parar de receber e-mails dele, envie um e-mail para logica-l+unsubscr...@dimap.ufrn.br. 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