Autumn 2012

Date Room Speaker Topic
August 30 CZ118 no meeting
September 6 CZ118 Reinhard Muskens, Tilburg University Introduction
September 13 no meeting
September 20 CZ118 Lasha Abzianidze, Tilburg University Linguistic Applications of Mereology
September 27 CZ117 informal working session
October 4 PZ46 informal working session/Sara L. Uckelman (Tilburg University) /Impossible Possibilites in Medieval Logic
October 11 PZ46 Hiroko Ozaki, Ochanomizu University Extractability as Deduction Theorem in Subdirectional Combinatory Logic
October 18 PZ46 Janine Reinert, Tilburg University Plural Quantification: The Why and the How
October 25 PZ47 Daisuke Bekki, Ochanomizu University Dependent Type Semantics: The Framework
November 1 PZ9 Daniel Altshuler, Universität Düsseldorf Using Discourse Structure to Probe Aspectual Meaning
November 8 PZ9 Yuri Ishishita, Ochanomizu University The Formulation of Presupposition by Illative Combinatory Logic
November 15 PZ46 Bruno Leclercq, Université de Liège Meinongian Logics and Their Limits
November 22 PZ9 Antje Rumberg, Utrecht University Towards a Semantics for Real Possibility
November 29 PZ46 SEMINAR CANCELLED
December 6 PZ46 Joke Spruyt, Maastricht University What’s in a Word? On the Philosophic Nature of Medieval Logic
December 13 PZ9 Kohei Kishida, University of Amsterdam A(nother) Sequent Calculus for Aristotle’s Syllogistic
December 20 D119 Terry Wilkinson, Tilburg University Identity, Variables, and Possible Worlds Semantics

Abstracts.

September 20

Lasha Abzianidze, Linguistic Applications of Mereology

Presentation/Report on the ESSLLI 2012 course by Lucas Champollion.

October 18

Janine Reinert, Plural Quantification – The Why and How

The talk will roughly follow the 2012 ESSLLI-seminar “Plurals in Semantics and Philosophical Logic” by Oystein Linnebo and Salvatore Florio.

Plural Logics allow quantification over plural expressions and thus promise

  1. greater faithfulness in formalization of plural natural language expressions than singular quantification has to offer
  2. to bypass set-theoretic artifacts in our semantics, as yielded for example by the Quinean paraphrase of the Geach-Kaplan sentence: “Some critics only admire one another”.

Keeping sets and pluralities apart has lead to some stunning results: Giving up the idea that our domain has to be a set, we are able to reach the universal domain, i.e., the plurality of absolutely everything. It hence seems that plural logic offers a way around non-well-founded set-theoretical and paraconsistent approaches to the problem of universality and absolute quantification.

The talk will provide the motivation and the technical background in Plural First Order Logic (PFO) for reaching this result, which includes a short discussion of mereological approaches to plurals. Depending on time it will address some of the following issues: How do set formation and pluralities interact? How is it possible that we do not end up with the same paradoxes as set theory? How can (non-set) pluralities be part of a mathematically precise language? Do set theory and plural logic “compete”? Is there good evidence for superplural reference (i.e. pluralities of pluralities) in natural language, and how can they be modeled? (Maybe there won’t be any clear answers to some of these questions – discussion is more than welcome!)

Background reading for the interested: Linnebo’s (2012) Stanford-entry on plural quantification; Linnebo: “Pluralities and Sets” (2010).

October 25

Daisuke Bekki, Dependent Type Semantics: The Framework

This talk introduces dependent type semantics, a new framework of natural language semantics based on dependent type theory. Main features of dependent type semantics are the following:

  1. it is dynamic: it analyzes E-type/donkey anaphora with well-formed representations.
  2. it is proof-theoretic: entailments between the representations can be calculated without recourse to their models.
  3. it is compositional: the semantic representations of sentences are derived from the lexicalized representations by a fixed number of combinatory rules.
  4. it explains accessibility: accessibility/inaccessibility of anaphora is reduced to the structural differences between proofs.

These are achieved by a specific way of combining type theoretical approaches (cf. Ranta (1994)) and the continuation-based approaches (cf. de Groote (2006)) to dynamic binding. From the perspective of dependent type semantics, the source of dynamics in natural language is the dependence on proofs of the preceding discourses.

November 8

Yuri Ishishita, The Formulation of Presupposition by Illative Combinatory Logic

This talk introduces the formulation of presuppositions by Illative Combinatoy Logic. Main features of Illative Combinatory Logic (ICL) are the following:

  1. A logic which consists of the combinators and the lambda terms
  2. A minimal predicate logic which lacks the notion of negation
  3. It has four variant systems, which includes the systems based on the notion of dependent types

From the perspective of natural language, the feature 2 is problematic for the lack of notion of negation, so in this talk I will provide the way to extend the system of ICL and formulate presupposition projection by use of the extended system.

November 15

Bruno Leclerq, Meinongian Logics and Their Limits

According to Alexius Meinong, statements such as “The round square is round (and square)”, “The golden mountain is made of gold”, “Pegasus has big wings” or “Unicorns have a horn on their forehead” should be seen as talking about some genuine (yet inexistent or even impossible) objects, and should be considered as true or false whether these objects possess the properties that are here attributed to them or not. On the contrary, Frege and Russell’s logical analyis tends to make these “objects” appear as concepts (or propositional functions) that can be meaningful eventhough they are not satisfied by any object at all. After a brief presentation of Meinongian logics as well as of their benefits and drawbacks compared to classical logic as well as to standard modal logics, we will show that Meinongian logics not only require a clear-cut distinction between two kinds of properties (nuclear and extranuclear) but also between two kinds of predications (encoding and exemplification) and, eventually, between two kinds of objects (those which encode and those which exemplify their properties), which somehow restores Frege’s clear-cut distinction between concepts and objects as well as between first order and second order properties.

November 22

Antje Rumberg, Towards a Semantics for Real Possibility

In our everyday lives we constantly encounter real possibilities. By a real possibility I mean a future possibility in a concrete situation that is compatible with our laws of nature. Those real possibilities are most adequately pictured within branching frameworks, which allow for a direct representation of alternative future continuations of one and the same moment.

In the first part of my talk, I will present a novel semantics for the framework of branching time that takes into account the local nature of real possibilities. Rather than evaluating sentences with respect to moment-history pairs, as in the so-called Ockhamist semantics, the evaluation will be relativized to pairs consisting of a moment and a set of transitions. The semantics developed along these lines unifies extant approaches and allows for a perspicuous treatment of future contingents by providing a fine-grained measure of how and how far the future has to unfold for their truth or falsity to become settled.

In the second part of my talk, I will suggest a dynamic modal explanation of models for real possibility that elucidates why all the alternative courses of events those models depict are compatible with our laws of nature. The fact that histories branch at a certain moment in a certain way will be accounted for by the potentialities of the objects existing at that moment and their local arrangement. The branching model as a whole will be built up step by step from the local future possibilities grounded in the potentialities of objects. In this way, we get a dynamic picture of real possibility, which is reflected by the employment of sets of transitions in the semantics.

December 20

Terry Wilkinson, Identity, Variables, and Possible Worlds Semantics

The classical concept of absolute equivalence as a criterion for identity has increasingly come under attack in the last 50 years. Peter Geach, among others, has made argument that identity is relative and hence context dependent, and denies that absolute identity can hold.

W.V.O. Quine and his ilk, on the other hand, staunchly defend the classical interpretation and indeed Quine uses it to discredit modal logic by pointing out the discrepancies that arise from the de re and de dicto distinction.

Borrowing examples from mathematics and the sciences, I will give a slightly different account of identity, one that is certainly less strict than the classical interpretation, but one that also does not exclude the possibility of absolute identity altogether. By properly situating the idea of a variable within a possible worlds semantics, we can make claim that cross-context identity does hold in some cases. Additionally we may be able to shed some light upon the issues of scope that occur in the de re/de dicto distinction, and properly account for the two kinds of counter-factual statements that seem to be relevant for distinguishing the role of properties and objects with regard to identity.


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