International Symposium - Argumentation in Intensional Contexts: Knowledge, Belief and Dialogue (20/21-5-2010)

Date:  May 20th/21th, 2010.

Location: Classroom Grades of the Faculty of Philosophy - University of Seville.

Organized by: Group on Logic, Language and Information. & University of Lille 3
A. Nepomuceno, M. Fontaine & C. Barés

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TALKS:

Lecturer: Cristina Barés Gómez (C.S.I.C.).

Tittle: Formalizing the hermeneutic method: Hermeneumatic methodology.

Abstract:

The different hermeneutic lines, starting with biblical hermeneutic, developed a way to approach the text based in a hermeneutic circle. This circle mix the structure that the text offers us with the structure that the interpreter has himself and it builds a dynamic process to developed the semantic of a language. The methodology that we’ll show here try to develop first the main structure of the language checking the text itself and by obtaining the meaning from the different level of formalizing the structure of a determined language, in our case the Ugaritic (ancient semitic language). The different level correspond to different subject that contributes it’s part to compound the completely structure of the language. By formalizing the levels of a text we’ll have a clear structure of one side of the hermeneutic circle, but we don’t lose the dynamic of the process because we take in account the language in its use, the realization of the language in a written discourse.

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Lecturer: Nicolas Clerbout (S.T.L. - C.N.R.S.).

Tittle: The Dialogical Outlook on Modal Validity. Rules and Strategies.

Abstract:

The thesis according to which all logical truths are necessary has come under some challenges. One of these consists in considering a modal language featuring an actuality operator (A) and in defending that there are formulas from this language which should count as logically true despite not being necessary. A typical example is (Aφ↔φ). Positions alike are held for example in [5] or more recently in [4]. From a model-theoretic perspective, such conceptions are described as taking validity being “truth in the actual world for every model”, and we shall call it “@-validity”.
In this work, we consider the Dialogical approach to (first-order) modal logic (see [1], [3]), and focus on the use of dialogical contexts and choices instead of model-theoretic points and accessibility relations when dealing with modal operators. We will insist on how modal operators are handled by means of (dialogical) rules for their use. Our purpose is to show how the Dialogical outlook provides insights on different modal semantic notions. To be more specific, we will display, within the Dialogical framework, a confrontation between frame-validity, @-validity and Humberstone’s universal satisfiability¹ ([2]). From this confrontation we will open discussions on the necessitation rule and on the topic of the relation between logical truth and necessity.

¹ The terminology “universal satisfiability” is due to T. Tulenheimo.

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Lecturer: Hans van Ditmarsch (L.L.I. - Sevilla).

Tittle: Dynamic epistemic logic, the Moore sentence, and the Fitch paradox.

Abstract:

Dynamic epistemic logics are modal logics of knowledge (and belief) change, with modal epistemic operators to describe knowledge and dynamic modal operators to describe change of knowledge. In such a logic we can analyze: the Moore-sentence: 'p is true but you/I don't know/believe that p is true' and also the Fitch-paradox: 'everything is knowable' is inconsistent with 'there is an unknown truth' namely when we interpret 'knowable' as 'known after an informative announcement'.

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Lecturer: David Fernández Duque (L.L.I. - Sevilla).

Tittle: Spatial representations of knowledge.

Abstract:

Not all truth is knowable. This phenomenon pops up in many different settings; in physics, there are bounds on how exact a measurement can be; certain sentences which refer explicitly to knowledge may lead to paradox if known (Moore sentences), and even in mathematics there are questions which are undecidable. Thus a proper treatment of truth and knowability should be able to distinguish between the two.
We present a way to make this distinction via spatial representations of truth and knowability. We will show how the spatial representation satisfies all of the properties we wish to have, and give examples of how it can be used to model related phenomena.

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Lecturer: Virginie Fiutek (Université de Groningen).

Tittle: Temporal doxastic logic meets conditional doxastic logic: a dialogical approach.

Abstract:

In this talk we focus on the connection between Bonanno’s temporal logic for belief revision and the conditional doxastic logic of Baltag and Smets. Both settings provide an axiomatic characterization of the AGM theory of belief revision and hence the link between these two settings can be made formally explicit. We show that both encode AGM in an equivalent way such that Bonanno’s frames provide particular instances of this type of belief-changing mechanisms. Then we present a dialogical reconstruction of Bonanno’s logic including the new condition of AGM-consistency introduced in Bonanno’s latest papers.

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Lecturer: Matthieu Fontaine (S.T.L. - C.N.R.S.).

Tittle: To Be is to Be Chosen, A Dialogical Understanding of Ontological Commitment.

Abstract:

One of the most important contribution of dialogical logic is to help us to understand quantification by mean of the notion of choice. Adopting a critical position with respect to standard free logics¹, we outline a new understanding of existence within the dialogical framework : to be is to be chosen.
Despite their ability to make explicit existential presupposition in logic, standard free logicians usually did it by means of an existence predicate. The result was a static understanding of ontological matters by focusing on relationship between propositions. Against this view, dialogical logic leads us to understand ontological commitment dynamically with respect to choices. More precisely, the idea is to grasp the meaning of quantification by taking into account the relationship between the choice of a constant and the resulting assertion. In this way, we can understand ontological commitment by means of choices governed by the application of logical rules. An interesting insight of this outlook is to display how ontological status of constant can change during a dialogue.
We will conclude with philosophical comments on fictionality and how to implement them in this framework.

¹ By standard free logics we mean the usual positive, negative and neuter free logics as defined in Lambert’s Free Logics [1997].

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Lecturer: Laurent Keiff (S.T.L. - C.N.R.S.).

Tittle: Dialogues on pseudo-logical constants.

Abstract:

What one may call "pseudological" constants have been a concern for antirealist theories of meaning since the invention of the first one, Prior's famous *tonk*. Regulatory concepts such as harmony have been proposed (especially by Belnap and Dummett) in order to back the claim that inference rules are meaning-constitutive. Technical adjustments aside, such concepts have often been criticized because they seem to show that inference rules are not *per se* sufficient to provide meaning, which was precisely Prior's original point. As it is well known, the dialogical approach claims to be a semantics, i.e. a theory of meaning, with a historical and technical link to antirealism. In this talk, we propose to examine how dialogues shed light on the issue of pseudological constants. We claim that dialogues are safe from the usual technique that yields *tonk*-like connectives, and provide a third way in the debate between model-theoretical and proof-theoretical semantics.

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Lecturer: Sébastien Magnier (S.T.L. - C.N.R.S.).

Tittle: PAC Vs. DEMAL.

Abstract:

In the literature on epistemic logic, we can find PAC which is a logic for multi-agent system with Public Announcement plus Common knowledge. This logic is expressed in model theory and Kripke’s structure. What we want to do here is to re-interpret the system PAC in the dialogical structure; it is what we call DEMAL. DEMAL stands for Dialogical Epistemic Multi-Agent Logic. The aim of this talk is to propose a new understanding of PAC and its operators through an original meaning theory via DEMAL. As we will see, the point of DEMAL is to conceive all of its operators in term of commitment or choice.

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Lecturer: Ángel Nepomuceno (L.L.I. - Sevilla).

Tittle: Information, Knowledge and Logic.

Abstract:

As a syntactic approach as a semantic approach to information are not without difficulties to understand and represent it as a communicative process in which logical operations may be involved. Though a relation with these three terms as arguments runs the risk of falling in an exclusive anthropocentric point of view, we propose a logical approach as a program that could be compatible with some theories and permits us to revise the consideration of information as a primitive concept.

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Lecturer: Aude Popek (S.T.L. - C.N.R.S.).

Tittle: Logical Dialogues from Middle Ages.

Abstract:

The mediaeval form of dialectical disputation known as obligationes was very popular during the fourteenth century. Briefly, an obligation is played by two participants called Opponent and Respondent. The disputation starts with Opponent putting forward a proposition called obligatum that Respondent accepts as true, false or dubious for the sake of the disputation, unless it is contradictory in itself. The disputation goes on with Opponent introducing successively other propositions that Respondent must grant, deny or doubt on the basis of inferential relation between the obligatum and previously granted or denied propositions. If there is no such inferential relation, Respondent answers on the basis of a common background knowledge. Respondent loses the disputation if he concedes a contradictory set of propositions. Several types of obligations exist. In this talk, we will focus here on the best-known obligational disputation called positio. In nowadays reconstructions of the positio, it is quite often that only the general rules which determine the general course of the dialogue and the role of each players are presented. Actually, there are two kinds of rules at stake: the general rules which specify the general organization of the game and the internal rules which describe the way a proposition can be defended according to its main connectives as well as to what Respondent knows. More accurately, the internal rules consist in an abstract description of all the possible Respondent's winning strategies. From this point of view, there is a striking similarity between the mediaeval and the dialogical approach to logic. The aim of my talk is to introduce one of the main theory of positio namely Walter Burley's. The presentation constitutes a first step towards a formal recosntruction of the theory of positio from a dialogical point of view.

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Lecturer: Fernando Soler-Toscano (L.L.I. - Sevilla), Fernando R. Velázquez-Quesada.

Tittle: A subjective-dynamic perspective to abductive reasoning.

Abstract:

Among the non-monotonic reasoning processes, abduction is one of the most important. It is usually described as the process of looking for explanations, and it has been recognized as one of the most commonly used in our daily activities. Still, the traditional definitions of an abductive problem and an abductive solution involve only theories and formulas, without explicitly relating them to an agent and her information. Following recent dynamic-epistemic logics, our work proposes a study of abductive reasoning from a subjective and dynamic point of view. Just like dynamic-epistemic logics describe the way the knowledge of an agent evolves via observations and inferences, we are interested in a framework that allows us to describe how the information of an agent evolves via abductive reasoning. The present work, the initial step towards that goal, discusses what an abductive problem and an abductive solution means from an agent's perspective, and explore several possibilities that arise when we consider different kinds of agents.

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Lecturer: José Luis Suárez (Universidad de Western Ontario -Canadá-).

Tittle: Humanidades digitales: cómo las Matemáticas y la Computación pueden ayudar a entender la cultura.

Abstract:

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Lecturer: Tero Tulenheimo (S.T.L. - C.N.R.S.).

Tittle: Divisibility of Time: A Modal Logical Perspective.

Abstract:

I formulate a logic L_TD which makes explicit certain ideas that G. H. von Wright put forward in his essay "Time, change, and contradiction" (1969). The logic is syntactically like basic modal logic with an additional unary operator but it has an interval-based semantics on structures with arbitrary linear frames. \square\phi is interpreted as meaning 'the current interval has a finite partition whose all members satisfy \phi.' L_TD is translatable into weak monadic second-order logic but not into first-order logic. The expressive power and the decidability properties of L_TD and its fragments are discussed.