{"id":531273,"date":"2024-09-11T10:13:26","date_gmt":"2024-09-11T13:13:26","guid":{"rendered":"https:\/\/revistapesquisa.fapesp.br\/?p=531273"},"modified":"2024-09-11T10:13:26","modified_gmt":"2024-09-11T13:13:26","slug":"without-fear-of-contradiction","status":"publish","type":"post","link":"https:\/\/revistapesquisa.fapesp.br\/en\/without-fear-of-contradiction\/","title":{"rendered":"Without fear of contradiction"},"content":{"rendered":"

Known as one Brazil\u2019s most original thinkers, Newton da Costa, a logician from Curitiba, died on April 16 at the age of 94 due to complications resulting from a fall he suffered at his home in Florian\u00f3polis. Having studied as a civil engineer and mathematician, Costa gained worldwide recognition for the development of paraconsistent logic, which is used to study contradictory opinions, situations, and theories. \u201cMy central concern has always been to think systematically about what knowledge is,\u201d he said in an interview with Pesquisa FAPESP<\/em> in 2008.<\/p>\n

\u201cNewton was a revolutionary: he established a new area of research in logic,\u201d says Luiz Henrique Lopes dos Santos, a philosopher from the School of Philosophy, Languages and Literature, and Human Sciences at the University of S\u00e3o Paulo (FFLCH-USP). In classical logic, as Santos explains, there is a principle that if you accept a contradiction, then you can accept anything, and logic therefore ceases to work \u2014 it is trivialized. \u201cIt is like a rule being broken in a game of chess. It then becomes a game without rules. In other words, the game is over, the rules are meaningless,\u201d continues Santos. \u201cNewton proposed that contradictions can be accepted without invalidating an entire system, preserving only certain rules of classical logic.\u201d<\/p>\n

Newton Carneiro Affonso da Costa was born in 1929, into a family of teachers and intellectuals, which explains his first name, in honor of the physicist Isaac Newton (1642\u20131727). He studied at the Federal University of Paran\u00e1 (UFPR), graduating first as a civil engineer in 1952 and then in mathematics, in which he completed a bachelor’s degree and a teaching qualification in 1956, followed by a PhD in 1961.<\/p>\n

In the late 1950s, he began to develop paraconsistent logic, at the time called \u201cinconsistent and nontrivial systems.\u201d His work was so unorthodox that he was deemed an eccentric in Brazil. With the help of Brazilian mathematician Artibano Micali (1931\u20132011), his ideas reached the French Academy of Sciences, but were almost not published due to claims that the word \u201cinconsistent\u201d did not exist in French. It was only when mathematician Marcel Guillaume of Clermont-Ferrand University found the word in a text by French mathematician, physicist, and philosopher Henri Poincar\u00e9 (1854\u20131912) that Costa\u2019s work received the green light. \u201cHis first recognition came from abroad,\u201d says Itala D’Ottaviano, a former student of Costa’s and now a professor of logic and fundamental mathematics at the University of Campinas (UNICAMP).<\/p>\n

At the suggestion of his friend, Francisco Mir\u00f3 Quesada, Peru\u2019s former Minister of Education, he changed the name of his theory to \u201cparaconsistent.\u201d In Greek, the prefix \u201cpara\u201d means \u201calongside,\u201d and Costa wanted to emphasize that rather than denying classical logic, he was adding something to it. The new name was officially presented by Quesada, at the 3rd<\/sup> Latin American Symposium on Mathematical Logic (SLALM), held at UNICAMP in 1976.<\/p>\n

The system created by Costa converged with a movement that began at the beginning of the twentieth century: the intuitionist logic and discussive logic of Polish logician Stanislaw Jaskowski (1906\u20131965). Paraconsistent logic began being developed along different lines in countries such as Poland, Australia, and Russia, applied to conflicting information in various fields of knowledge, from robotics to transport and medical diagnostic systems, including psychoanalysis.<\/p>\n

Quasi-truth
\n<\/strong>In 1967, Costa moved from Curitiba to S\u00e3o Paulo, where he taught classes at USP\u2019s Institute of Mathematics and Statistics and at UNICAMP. He was a professor at both universities until he retired in 1984. In the mid-1980s, he became a professor at FFLCH-USP and began teaching the philosophy of science.<\/p>\n

In the same decade, he worked with Chilean mathematician Rolando Chuaqui Kettlun (1935\u20131994), on the theory of quasi-truth, explained in books such as O conhecimento cient\u00edfico<\/em> (Scientific knowledge; Paulus, 2018). \u201cFor me, this concept is the second most important thing of all of his work,\u201d says Edelcio Gon\u00e7alves de Souza, a former student of Costa and professor at USP\u2019s Department of Philosophy. \u201cHe used to explain it with the following example: classical mechanics is a false theory, because it was followed by the theory of relativity. But to build a building, classical mechanics is used because \u2018it works.’ Classical mechanics is, therefore, a quasi-true science.\u201d<\/p>\n

In the 2000s, together with physicist Francisco Antonio D\u00f3ria of the Federal University of Rio de Janeiro (UFRJ), Costa began studying problems linked to this field, applying Kurt G\u00f6del’s (1906\u20131978) undecidability proof and theorem of incompleteness. \u201cNewton proved that there is no way to predict whether or not a system will enter a state of chaos. In other words, he showed that chaos is undecidable,\u201d says Souza, from USP. \u201cHe asked logical questions about physical phenomena\u2014ones that physicists didn\u2019t usually ask.\u201d<\/p>\n

Costa moved to Florian\u00f3polis in 2003 to be closer to his grandchildren, working as a professor at the Federal University of Santa Catarina (UFSC) until 2022. \u201cHe used to say that his objective as an educator was to ‘throw the snake into the students’ Eden,’ to shake up their ideas,\u201d recalls Jonas Arenhart, his colleague at UFSC\u2019s Department of Philosophy.<\/p>\n

Three major logic groups were formed around him: one at UNICAMP, another at USP\u2019s Department of Philosophy, and the third at UFSC, in the last phase of his career. \u201cToday there are several logic groups in Brazil that were influenced by these three collectives,\u201d says D’Ottaviano, from UNICAMP.<\/p>\n

As a visiting professor or researcher, Costa worked at institutions in Chile, Australia, the USA, Mexico, Italy, France, and other countries. In 1989, he was admitted as a member of the International Institute of Philosophy, based in Paris. He was also a member of the International Academy of Philosophy of Science and the American Association for the Advancement of Science. In 1998, he was awarded the Copernicus Medal by the Nicolaus Copernicus University in Toru\u0144, Poland, and the title of professor emeritus at UNICAMP.<\/p>\n

The Brazilian Logic Society\u2019s annual Newton da Costa award, created by Jean-Yves B\u00e9ziau of UFRJ in 2015, is named in his honor. B\u00e9ziau, a French-Swiss philosopher and mathematician, moved to Brazil to be supervised by Costa for his PhD, which he defended at USP in 1996. The S\u00e3o Paulo School of Advanced Science in Contemporary Logic, Rationality, and Information, funded by FAPESP and supported by UNICAMP\u2019s Center for Logic, Epistemology, and History of Science (CLE), held an event in Costa\u2019s honor last year. Coordinated by D’Ottaviano, the event brought together 170 people, including students and teachers from Brazil and abroad. It was one of Costa\u2019s last public appearances.<\/p>\n

Newton da Costa leaves his wife, Neusa, to whom he was married for almost seven decades, his children Newton Jr., Marcelo, and Sylvia L\u00facia, and two granddaughters.<\/p>\n","protected":false},"excerpt":{"rendered":"Newton da Costa earned international recognition for his revolutionary systems in the field of logic","protected":false},"author":740,"featured_media":531274,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[1348],"tags":[228,246],"coauthors":[4572],"class_list":["post-531273","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-obituary","tag-engineering","tag-mathematics"],"acf":[],"_links":{"self":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/531273","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/users\/740"}],"replies":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/comments?post=531273"}],"version-history":[{"count":1,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/531273\/revisions"}],"predecessor-version":[{"id":531279,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/531273\/revisions\/531279"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/media\/531274"}],"wp:attachment":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/media?parent=531273"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/categories?post=531273"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/tags?post=531273"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/coauthors?post=531273"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}