Dear Cheerful Logicians and Friends of Logic, There are six events to announce this week: one each on Monday, Tuesday, and Wednesday, then a whopping three events on Friday. I hear rumblings of further events finding their way onto the calendar as well, so keep your eye on the supergroup website, which you can find at https://sites.google.com/view/logicsupergroup/ in case of further talk announcements.
Details about all of these talks are also found below. Supergroup Talk Speaker: Alex Belikov (Lomonosov Moscow State University) Title: On Bivalent Semantics and Natural Deduction For Some Infectious Logics Time and Date: Friday, October 2 09:00 GMT-5 Link: https://ksu.zoom.us/j/93495801842?pwd=WERmbTNjL3ZPWmNYekxucDBSc1E3dz09 *Meeting ID*: 934 9580 1842 *Passcode*: bivalent Abstract: In this work, I present a variant of so-called ‘informational semantics’, a technique elaborated by E. Voishvillo, for two quatervalent infectious logics, Deutsch’s Sfde and Szmuc’s dSfde in order to illuminate how incompleteness and inconsistency (understood in the ‘infectious’ way) effect on the truth and falsity conditions for conjunction and disjunction. In a nutshell, I suggest two kinds of semantical conditions: ‘affirmative’ one for logics with infected gaps and ‘rejective’ one for those where gluts are infected only. With regard to the technical part, I formalize these logics in the form of natural deduction calculi, thereby solving several problems: to fill the corresponding gap in the study of a proof- theoretical aspect of infectious logics; to revise Petrukhin’s result for Sfde; to provide simple natural deduction systems for Sfde and dSfde, representing a fundamental symmetry between them and forming a convenient basis for further extensions. Talks by Other Groups: *Logic and Metaphysics Workshop* (CUNY) *Speaker: *Daniel Hoek (Virginia Tech) *Title: *Coin flips, Spinning Tops and the Continuum Hypothesis *Time and Date: *Monday, September 28 15:15 GMT-5 *Link: * https://gc-cuny.zoom.us/j/92439891639?pwd=OVdlUmVhbG4rRTE1b0ZBNzU5TzlWdz09 *Meeting ID: *924 3989 1639 *Passcode: *346380 *Abstract: *By using a roulette wheel or by flipping a countable infinity of fair coins, we can randomly pick out a point on a continuum. In this talk I will show how to combine this simple observation with general facts about chance to investigate the cardinality of the continuum. In particular I will argue on this basis that the continuum hypothesis is false. More specifically, I argue that the probabilistic inductive methods standardly used in science presuppose that every proposition about the outcome of a chancy process has a certain chance between 0 and 1. I also argue in favour of the standard view that chances are countably additive. A classic theorem from Banach and Kuratowski (1929), tells us that it follows, given the axioms of ZFC, that there are cardinalities between countable infinity and the cardinality of the continuum. (Get the paper here: https://philpapers.org/archive/HOECAT-2.pdf). *Lógicos em Quarentena* *Speaker: *Catharina Dutilh Novaes *Title: *Who's afraid of adversariality? Conflict and cooperation in argumentation *Time and Date: *Tuesday, September 29, 09:00-11:00 GMT-5 *Link: *https://meet.google.com/gnq-cbcs-kri *Abstract: *Since at least the 1980s, the role of adversariality in argumentation has been extensively discussed. Some authors criticize adversarial conceptions and practices of argumentation and instead defend more cooperative approaches, both on moral and on epistemic grounds. Others retort that argumentation is inherently adversarial, and that the problem lies not with adversariality per se but with overly aggressive manifestations therof. In this paper, I defend the view that specific instances of argumentation are (and should be) adversarial or cooperative proportionally to pre-existing conflict. What determines whether an argumentative situation should be primarily adversarial or primarily cooperative are contextual features and background conditions, in particular the extent to which the parties involved have prior conflicting or convergent interests and goals. I articulate a notion of adversariality in terms of the relevant parties pursuing conflicting interests, and argue that, while cooperative argumentation is to be encouraged whenever possible, conflict as such is an inevitable aspect of human sociality and thus cannot be completely eliminated. *Helsinki Logic Seminar* *Speakers: *Cheryl Misak and Simon Blackburn *Time and Date: *Wednesday, September 30, 06:00 GMT-5 *Link: *https://wiki.helsinki.fi/display/Logic/Seminar *Abstract: *Cheryl Misak: The theory of general relativity drove Russell in 1928 to argue that we can refer to unobservable theoretical entities only through an understanding of their structural properties. At the end of that decade, two eminent philosophically inclined Cambridge mathematicians explored the issue. Simon Blackburn will show how Max Newman exploded Russell’s structuralism by noting that to say of two collections that they share a specified structure asserts nothing more than that they have the same cardinality. He will also show that Frank Ramsey is thought to have developed a technique (“Ramsey Sentences”) for the empiricist who wants to reduce theory to observation. Ramsey’s technique however, seems to open him to Newman’s problem, and Simon puzzles over why this seems not to have bothered him. Cheryl Misak will then argue that Ramsey in fact is not open to Newman’s Problem. Ramsey Sentences are much richer and much more interesting, in that they are situated in a context of inquiry and allow for refinement and improvement. Simon Blackburn: ”Why is Newman missing?” It is generally agreed that the idea of the Ramsey sentence of a theory has an origin in “Theories” written in note form in 1929, the last year of Ramsey’s productive life. Yet in 1928 his friend Max Newman had published, in Mind, a paper which has ever since dominated discussions of Ramsification. The paper was directed at Russell’s 1927 book The Analysis of Mind, and Russell conceded its criticism was both fundamental and correct. Why then did Ramsey ignore it— when Russell had in effect preceded him in the application of Ramsey sentences in defining “structural realism” ? I suggest that the answer is that Ramsey was not interested in anything like Russell’s foundational project (nor Carnap’s) but perhaps in something more like David Lewis’s 1970 paper “How to Define Theoretical terms”. *UConn Logic Group* Speaker: Lenore Blum (CMU) Time and Date: Friday, October 2, 12:00 GMT-5 *See supergroup calendar for further details* *Berkeley Logic Colloquium* *Speaker: *Matthew Harrison-Trainor *Time and Date: *Friday, October 2, 18:00 GMT-5 *Link: *http://logic.berkeley.edu/events.html <http://logic.berkeley.edu/events.html> *Title: *Scott complexity of countable structures *Abstract: *Dana Scott proved that every countable structure has a sentence of the infinitary logic Lω1ω which characterizes that structure up to isomorphism among countable structures. Such a sentence is called a Scott sentence, and can be thought of as a description of the structure. The least complexity of a Scott sentence for a structure can be thought of as a measurement of the complexity of describing the structure. I will give an introduction to the area, and then focus on three subtopics: connections with computability, Scott complexity of particular structures, and complexity in classes of structures. Other Notes and Announcements: - *The Logic Supergroup has a YouTube channel!* Recordings of almost all talks are available at https://www.youtube.com/channel/UCqOAS8SHP-5nGjYEE2FE6xw Yay for logic! -- 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 [email protected]. Para ver esta discussão na web, acesse https://groups.google.com/a/dimap.ufrn.br/d/msgid/logica-l/CAMTR990tCC1GNrwrSNae3%3DFfnNNsOayUSN4afqxcC77oMXtU3A%40mail.gmail.com.
