20-23 juin 2011 Paris (France)

Program and Abstracts


Monday 20 June :
Ecole normale supérieure, 24, rue Lhomond, salle E314.
13h Welcome - coffee.
14h10-15h10: Anil Gupta 15h15-16h15:  Stefan Wintein pause
16h30-17h30: Henri Galinon
17h35-18h35 : James Woodbridge

Tuesday 21 June :
Ecole normale supérieure, 24, rue Lhomond, salle E314.

9h-10h : Gila Sher 10h05-11h05 : Shawn Standefer
11h20-12h20: Pascal Engel
Lunch break
14h10-15h10: Philippe de Rouilhan 15h15-16h15: Luca Tranchini pause
16h30-17h30: Paul Egré & David Ripley 17h35-18h35Douglas Patterson
19h - Conference dinner
Wednesday 22 june :
Université Paris-I, 12, place du Panthéon Salle 1.
9h-10h: Friederike Moltmann
10h05-11h05: James Shaw
pause 11h20-12h20 : Stephen Read
Lunch Break
14h10-15h10: Volker Halbach 15h15-16h15:  Dora Achourioti pause
16h30-17h30: Julien Boyer
17h35-18h35: Gabriel Sandu [canceled]

Thursday 23 June:
Université Paris-I, 12, place du Panthéon Salle 1.
9h-10h : Michael Glanzberg
10h05-11h05: Denis Bonnay
11h20-12h20: Leon Horsten
13h - Closure

Abstracts :

Theodora Achourioti (University of Amsterdam)
"Truth in Natural Language"
The talk concerns the formalisation of the truth-predicate as it occurs in natural language and the philosophical problems thereof. I will discuss the appropriateness of semantic and axiomatic theories of truth for capturing the ordinary notion of truth, as well as the question of whether the latter is inconsistent. I will offer some proposals for modelling the behavior of the truth-predicate in natural language, based primarily on empirical observations.

Julien Boyer (University Paris-1)
"Between Proof and Truth"
We consider two versions of truth as grounded in verification procedures: Dum- mett’s notion of proof as an effective way to establish the truth of a statement and Hintikka’s GTS notion of truth as given by the existence of a winning strategy for the game associated with a statement. Hintikka has argued that the two notions should be effective and that one should thus restrict one’s attention to recursive winning strategies. In the context of arithmetic, Bonnay (2004) has shown that the two notions do not coincide: on the one hand, proofs in P A do not yield recursive winning strategies for the associated game; on the other hand, there is no sound and effective proof procedure that captures recursive GTS truths. He then con- siders a generalized version of Game Theoretical Semantics by introducing games with backward moves. In this setting, a connection is made between proofs and recursive winning strategies. In this paper, we discuss this results and then apply this distinction between two kinds of verificationist procedures to a recent debate about how we recognize the truth of Go ̈delian sentences.

Denis Bonnay (University of Paris-X, ENS)
"Truth and dependence" (joint work with F. van Vugt)
Truth may yield paradoxes and Tarski showed how widespread the problem is by proving that no sufficiently rich classical language can contain its own truth definition on pain of inconsistency. In order to tackle with the semantic paradoxes, one should obviously try and understand which features of sentences are responsible, together with occurrences of the truth predicate, for the reported misbehavior.
But the same question can be asked from a dual perspective. Some sentences, including sentences containing the truth predicate, are clearly unproblematic: why is it that they are immune to the semantic paradoxes? Following a widespread intuition, unproblematic sentences are such that their value ultimately depends on how the world is like. The truth-value of (3) "Emily Dickinson was born in Amherst" directly depends on where Emily Dickinson was born. When evaluating (4) "The sentence `Emily Dickinson was born in Amherst' is true", we are led again to evaluate (3). Hence the truth-value of (4) depends, albeit indirectly, on where Emily Dickinson was born. To put it roughly, a sentence should considered grounded if its truth value can be established regardless of the truth or falsity of other sentences, or if its truth value can be established based on the truth or falsity of other sentences that are, themselves, grounded.
In the talk, I will compare two ways of making this precise: the "classical" account of groundedness, due to Kripke, and a more recent proposal by Leitgeb. These two accounts differ in the approach they choose. Kripke's notion of groundedness is a by-product of the fixed-point construction aimed at characterizing the extension of the truth-predicate. By contrast, groundedness is Leitgeb's primary target, which is to be attained by means of a fixed-point construction using a notion of dependence. However, one might hope that the two accounts are extensionnally equivalent, if there is one "right" notion of groundedness. But they are not. I will show that the difference is due to three parameters, some of which are extrinsic to the notion of groundedness, some of which are more intrinsic. By setting these parameters alike, one can show that the direct and the indirect route are, after all, equivalent.

Paul Egré (IJN, Paris), David Ripley (University of Melbourne)
"Tolerant Truth and permissive consequence"
In three-valued logic it is possible to distinguish two notions of truth, which we call strict truth (for a sentence to take value 1) and tolerant truth (for a sentence to take value > 0). Permissive consequence can be defined as the entailment from strictly true premises to tolerantly true conclusions. We discuss the fruitfulness of these notions for the treatment of vagueness and the sorites paradox, and compare ways of defining a satisfactory conditional connective for the notion of permissive consequence.

Pascal Engel (University of Geneva)
"Deflationism and the norm of truth"
It has been objected to deflationists that they cannot account for the normativity which is attached to truth, belief, and assertion. The deflationist's answer has consisted either in denying that there are norms of assertion or norms attached to truth, or in claiming that they can account for these norms at everyone's satisfaction. I am not satisfied. I shall try to show that the deflationist ressources are too poor or too inadequate and that, once properly located, the nornative load of truth is a strong argument against deflationism.

Henri Galinon (University of Paris-1)
" Deflationary truth and the reflexive consequences of a theory"
I argue that the act of accepting an infinitary object such as a theory involves an antecedent act of semantic ascent, and that the propositions that are the actual objects of the subject's judgements involve from the start a minimal concept of truth. If we are correct, the content of a subject's judgements who accepts a theory necessarily exceeds in logical strength the content of the theory itself. I draw some consequences of these remarks in connection to deflationism about truth.

Michael Glanzberg (University of California, Davis)
"Complexity and Hierarchy in Truth Predicates"
Many approaches to the paradoxes wind up endorsing highly complex truth predicates. Such predicates are often complex by recursion-theoretic measures, and in some cases, also involve stratification of truth into distinct levels in a hierarchy. This paper explores the role of such complexity in our understanding of the nature of truth, its expressive role, and its role in semantics. The paper defends both complexity and stratification as fundamental aspects of truth (and some related notions). Along the way, it also argues that such complex truth predicates fare well compared to simpler truth predicates paired with alternative notions like determinateness.

Anil Gupta (University of Pittsburgh)
"Remarks on Tarski's Convention T"
My remarks will be directed to three interconnected topics: deflationism, paradoxes, and the proper interpretation of the Tarski biconditionals.

Volker Halbach (University of Oxford)
I will discuss axiomatizations of truth that are purely disquotational. The resulting theories are - perhaps somewhat surprisingly - not necessarily weak. In fact, depending on the details of the formulation, they can be as strong as the strongest theories based on compositional axioms for truth.

Leon Horsten (University of Bristol)
"Minimally adequate and more than minimally adequate truth theories"
The talk is based in part on joint work with Martin Fischer (München).
We confine ourselves to classical axiomatic theories of truth.
We distinguish between:
(1) Truth theories that are minimally adequate for performing the function of the truth predicate. Here we focus mainly on the role of truth in mathematical contexts (as opposed to ordinary language contexts).
(2) Truth theories that go beyond this minimal function but which have only sound consequences. Here we focus on reflexive truth theories that have no untoward consequences.
It will be argued that in mathematical contexts, truth is used as an expressive device, but the reflexivity of truth is not needed. Concretely, a conservative but non-interpretable truth predicate (equivalent to ACA_0) is sufficient. If one wants a reflexive truth theory that is sound, then a “positive” version of the Friedman-Sheard theory is attractive.

Friederike Moltmann (IHPST, CNRS)
"'Truth Predicates' in Natural Language"
In this talk, I would like to take a closer look at the way truth is in fact expressed in natural language. In English, there appear to be three different types of apparent ‘truth predicates’:
(1) a. That S is true.
b. That S is the case.
c. That S is a fact.
It is a common view that these constructions are equivalent, all stating the truth of the proposition that S. I will argue that these three constructions are fundamentally different both in construction type and in content. 'Is true' serves to state the status of a representational entity of some kind, 'is the case' reflects an Austinian notion of truth, and 'is a fact ' serves to state the existence of a Strawsonian fact, obtained from a true proposition.

Douglas Patterson (Kansas State University)
"Tarski on Truth : Theory, Definition and Concept in "Intuitionistic Formalism" "
In this talk I will set out some of the background of Tarski's work by looking at important views of his teachers Tadeusz Kotarbinski and Stanislaw Lesniewski. With the understanding of the assumed philosophy of language and logic of the articles set out in this manner, I will look at a number of familiar issues. I will sort out Tarski's conception of "material adequacy", discuss the relationship between a Tarskian definition and a conceptual analysis of a more familiar sort, and consider the consequences of the views presented for the question of whether Tarski was a deflationist or a correspondence theorist.

Stephen Read (University of Saint-Andrews)
"Truth, Signification and Paradox"
Thomas Bradwardine's solution to the semantic paradoxes, presented in his 'Insolubilia' written in Oxford in the early 1320s, turns on two main principles: that a proposition is true only if things are wholly as it signifies; and that signification is closed under consequence. After exploring the background in Walter Burley's account of the signification of propositions, I consider to what extent Bradwardine's theory is compatible with the distribution of truth over conjunction, disjunction and the conditional (the commutative or compositional principles)

Philippe de Rouilhan (IHPST, CNRS)
"Truth at Work : Generalizing and Solving Frege's Paradox"
1. In its original version, Frege’s paradox (FP) is related to Frege’s distinction between Objects and Concepts, which led Frege to the paradigmatic, paradoxical statement that the Concept horse is (an Object and thus) not a Concept. Let’s remember the lesson: By using the expression “the Concept horse”, we don’t succeed in speaking of the Concept itself, we only speak of an Object.
The prima facie best idea of solution of FP can be credited to Husserl, even though he never explicitly addressed FP : if Frege hadn’t unduly applied the metaphor of completeness vs. incompleteness (or saturatedness vs. unsaturatedness), beyond senses, to references, he would have been led to acknowledge that Concepts are Objects, and thus that, by using the expression of the form “the Concept F”, we do speak of the Concept F itself. Unfortunately, the thesis that Concepts are Objects leads to a Russell-like paradox. So, per absurdum, some Concepts are not Objects, and, if F is one of them, FP is back: By using the expression “the Concept F”, we don’t succeed in speaking of the Concept itself, we only speak of an Object.
2. The essential and unfortunate consequence of FP, for Frege, was that the system of science couldn’t be explained within the same logical framework as that system : in order to have his disciple understand the system, the master would have to speak of all Concepts as if they were Objects, which was not the case. More generally for us, by the same token, if S be a typed system of science, whose higher-order variables range over domains not all included in the basic domain, it might seem impossible to explain S within the same logical framework as S: this is what I call Generalized Frege Paradox (GFP).
The main aim of the talk will be to solve GFP. The idea is to put truth at work as Davidson taught us to do. To explain a language is not to translate its sentences, but to say what they mean, or, as Davidson put it, to interpret them. According to an idea of Frege himself, taken up again by Wittgenstein, Carnap, and Davidson, to interpret a sentence amounts to giving its truth conditions. Davidson, more precisely, required that the truth conditions of the sentences be given in the form of a recursive theory of truth à la Tarski for the language under consideration. In order to solve GFP, one must show that, for any language, L, at stake in GFP, it is possible recursively to define truth for L in the same logical framework as L. I’ll focus on the most interesting case, when L is a language of finite order ≥ 4 founded on the extensional, monadic theory of types. 
3. The interpretation of the language, L, of the system of science is possible in the same logical framework as L (GFP is solved), but we well know that it remains impossible in L itself. In order to overcome this impossibility, could one resort to a neo-Davidsonian conception of interpretation founded on a post-Tarskian conception of truth ? That’s another story.

Gabriel Sandu (University of Helsinki)
"Indeterminacy and truth"
Kripke (1975) introduces a partially interpreted predicate, the truth-predicate, whose extension and counter-extension are disjoint but not complementary. Certain sentences, like the Liar, belong neither to the extension nor to the counter-extension of the truth-predicate.
Hintikka and Sandu (1989) introduce partially interpreted connectives and quantifiers. The resulting languages define their own truth-predicate. In this setting, the Liar is neither true nor false. The focus on the paper is not on the truth-predicate, but on certain indeterminate sentences which can be interpreted probabilistically, applying von Neumann’s Minimax theorem.

James R. Shaw (Pittsburgh University)
"Semantics for semantics"
One reason we need a formal theory of truth is to act as a compositional semantics for semantic vocabulary—a theory of how speakers pair content with utterances of whole sentences on the basis of the meanings of their parts. Providing such a theory faces an under-appreciated problem. Successful reflexive uses of words like “true” force their compositional semantic values to be highly non-standard: they cannot be modeled using extensions. This rules out a wide range of formal theories of truth as structurally inadequate. After explaining this problem, I explore how our compositional theories must be liberalized to accommodate the peculiarities of semantic terms like “true” and extract some lessons from this liberalization.

Gila Sher (University of Californa, San Diego)
"Composite Correspondence"
Given (a) the complexity of the world, (b) our desire to understand it in its full complexity, (c) the mind’s limitations, and (d) its theoretical capacities, the questions arise: 
1. Is there a standard of truth for theories of the world? 
2. Is such a standard a correspondence standard?
3. How intricate is such a standard?
4. How unified is it?
5. How does it deal with hitherto problematic fields like mathematics & logic?
In this talk I propose a constructive answer to these questions.

Shawn Standefer (Pittsburgh University)
"On Universality"
Universality is frequently brought up in discussions of truth. There are different notions of universality and their import for theories of truth is not clear. I distinguish the different notions found in the writings of Tarski and Fitch. I indicate what they tell us about adequate theories of truth. I close by using considerations of universality to argue for a generality requirement on theories of truth.

Luca Tranchini (University of Tübingen)
"Truth from a proof-theoretic perspective"
First, the so-called `proof-theoretic semantics' is presented: its central concept is the one of validity, which correctly applies to the arguments that denote proofs. In terms of validity, Dummett's anti-realist characterization of the notions of truth and correct assertion is clarified. Dummett's characterization is rejected in favour of an alternative one. At the core of the proposed account is the idea that valid arguments may fail to be recognized as such.

Stefan Wintein (Tilburg University)
"Modifying Kremer's Modified Gupta Belnap Desideratum"
In a recent paper, Philip Kremer proposes a formal and theory-relative desideratum for theories of truth that is spelled out in terms of the notion of `no vicious reference'. Kremer's Modified Gupta-Belnap Desideratum (MGBD) reads as follows: if theory of truth T dictates that there is no vicious reference in ground model M, then T should dictate that truth behaves like a classical concept in M. In this paper, we suggest an alternative desideratum (AD): if theory of truth T dictates that there is no vicious reference in ground model M, then T should dictate that all T-sentences are strongly assertible in M. We illustrate that MGBD and AD are not equivalent by means of a Generalized Strong Kleene theory of truth and we argue that AD is preferable over MGBD as a desideratum for theories of truth.

James Woodbridge (University of Nevada, Las Vegas)
"Revisiting Truth as a Pretense"
The basic presentation of the pretense account of truth (or rather, truth-talk) appeared in print in 2005. The central thesis of the view is that the notion of truth is a pretense—really there is no such property, we just talk "as if" there were. We make as if to describe things as having or lacking properties called “truth” and “falsity” in order to make claims of other (more complicated) sorts indirectly. The semantic mechanism at work in the operation of truth-talk is a kind of pretense akin to games of make-believe. Despite its involving a kind of fiction, the mechanism of semantic pretense still allows truth-talk to serve as a means for making genuine assertions about the world. Because of how it functions, truth-talk serves to extend the expressive capacity of a language; centrally, it allows us to make general claims of a special and complicated sort. This has important connections to deflationary accounts of truth. The pretense account of truth-talk also has interesting consequences for issues including the liar paradox and the notion of meaning. This talk is a re-examination of the pretense account, in light of the extensions, re-situating, and defenses of it that have developed over the past 5 years through my collaboration on the view with Bradley Armour-Garb.
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