Autumn 2013

Tuesday 1 October: Progress Report

Speaker: Lasha Abzianidze

Time&Place: 16.45-18.30, Room DZ 6

Title: Natural tableau – reasoning beyond toy examples


In order to cope with problems from entailment data sets, we need to a) extend the natural tableau with extra rules, and b) guarantee better conversion of linguistic expressions into lambda logical forms. At this stage we focus on the fracas data set (due to its simplicity and design) and by introducing new rules we enable the tableau to prove some entailments from the set. Before automated reasoning some non-trivial (and non-intuitive) modifications of CCG parse trees are necessary for obtaining fine-grained lambda logical forms. During the reasoning process, several readings of sentences (caused by ambiguity in quantifiers’ scopes) are also taken into account. In the end, the demo of the system will be offered.

Tuesday 15 October: Invited lecture

Speaker: Reinhard Muskens

Time&Place: 16.45-18.30, Room DZ 6
Title: Facts, Frames, and Data Logic

Abstract: In this talk, which reports on ongoing work, I will sketch
ways of combining 1) lexical semantics in the tradition of Fillmore,
Barsalou, Loebner, Petersen, and others (Frame Semantics), and
2) phrasal semantics in the tradition that started with the
work of Richard Montague (Type-Logical Semantics). I will argue
that the frames of Frame Semantics represent possible /facts/ and
that these possible facts can have two roles: a) they can take on
some of the functions played by possible worlds in more traditional
accounts of semantics (‘facts of assessment’) and b) they provide
the material for ‘atomic’ statements expressing that a certain fact
obtains (given a fact of assessment).

While it is sometimes claimed (e.g. in Barsalou’s work) that the
frames of Frame Semantics are adequate for representing operations
such as negation, disjunction, and quantification, to this day
no proper logic for these operators based on frames has been
forthcoming. Type logic, on the other hand, can combine insights
from both traditions and can easily deal with logical operators
that are not readily expressed with the help of frames.

A semantics for facts and certain ‘data sets’ of possible facts
was developed in Veltman 1985 and Veltman’s ‘Data Semantics’
has been a huge inspiration for the present work. I will
use a 3-valued type logic to model some of Veltman’s insights,
but will also deviate from these insights in non-trivial ways.
The resulting system has also some affinities with my earlier
work on expressing ideas from Situation Semantics in type logic.


Tuesday 29 October: Invited lecture

Speaker: Robert van Rooij

Time&Place: 16.45-18.30, Room DZ 6
Title: Nonmonotonicity and partiality: Pragmatic interpretations of vague expressions.
Abstract: Recent experiments have shown that naive speakers find borderline contradictions involving vague predicates acceptable.  Cobreros et al (2012a)  proposed a pragmatic explanation  of the acceptability of borderline contradictions, building on a three-valued semantics.  In a reply, Alxatib, Pagin & Sauerland (2013)  show, however, that the pragmatic account predicts the wrong interpretations for some examples involving disjunction, and  propose as a remedy a semantic analysis instead, based on fuzzy logic. In this paper we provide an explicit pragmatic interpretation rule and show that with its help the problem can be overcome in pragmatics after all. Furthermore, we use this pragmatic interpretation rule to define a new (non-monotonic) consequence-relation and discuss some of its properties.

Tuesday 12 November: Invited lecture

Speaker: Paolo Maffezioli

Time&Place: 16.45-18.30, Room DZ 6
Title: Proof Theory for Dynamic Epistemic Logic
Abstract: Dynamic epistemic logics are widely acknowledged as one of the most natural framework for the representation of information change. However, while their model-theoretic properties become better understood, their proof theory has been slow to develop. In this talk I will take some step to fill this void. First, I will provide an overview on the state-of-the-art of the proof theory for modal logics, with particular emphasis on epistemic logics. Then, I will focus on the logic of public announcement and show how to find Gentzen-style proof systems in an uniform and modular manner. I conclude with a discussion on how to extend the framework to preference upgrade.

Tuesday 10 December: Progress Report

Speaker: Janine Reinert

Time&Place: 16.45-18.30, Room DZ 6
Title: Impossible Miscellanea and a particularly recalcitrant sort of counterpossible conditional
Abstract: It has frequently been suggested to extend Lewisian Modal Realism (Lewis 1986) with representational (i.e. ersatz) impossible “worlds” (cf. Restall 1997, Mares 1997, Berto 2012). While such hybrid approaches may have some intuitive advantages over concrete impossible worlds, and, in addition, are prima facie able to retain Lewis’s reductive analysis of possibility, it can be doubted whether they offer (a) a metaphysically adequate analysis of impossibility, (b) a plausible account of how their “worlds” represent, or (c) indeed solve the problems due to which they are introduced. Among the latter, the most pertinent is the Granularity Problem, i.e. the vacuous truth of counterpossible conditionals. I will show how a subclass of these conditionals remains unsolved by Restall’s and Berto’s proposals, and discuss Mares 1997 in the light of this problem. Then I will argue that while he may be able to provide a technical “solution” to such problems, his underlying metaphysics is questionable, at least when judged against the backdrop of impossible doxastic content. Lastly, if time allows, I want to sketch how similar concerns arise in an altogether different metaphysics of modality: Priest’s 2005 noneism.

-Berto, Francesco. 2010. Impossible Worlds and Propositions. Against the Parity Thesis. Philosophical Quarterly 60 (240), 471–486.
-David k. Lewis. 1986. On the Plurality of Worlds. Oxford: Blackwell.
-Edwin D. Mares. 1997. Who’s Afraid of Impossible Worlds? Notre Dame Journal of Formal Logic, 38(4):516–526.
-Greg Restall. 1997. Ways Things Can’t Be. Notre Dame Journal of Formal Logic, 38(4):583–596.

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