
863Logicality and InvarianceBulletin of Symbolic Logic 14 (1): 2968. 2006.What is a logical constant? The question is addressed in the tradition of Tarski's definition of logical operations as operations which are invariant under permutation. The paper introduces a general setting in which invariance criteria for logical operations can be compared and argues for invariance under potential isomorphism as the most natural characterization of logical operations.

205Vagueness, uncertainty and degrees of claritySynthese 174 (1). 2010.In this paper we compare different models of vagueness viewed as a specific form of subjective uncertainty in situations of imperfect discrimination. Our focus is on the logic of the operator “clearly” and on the problem of higherorder vagueness. We first examine the consequences of the notion of intransitivity of indiscriminability for higherorder vagueness, and compare several accounts of vagueness as inexact or imprecise knowledge, namely Williamson’s margin for error semantics, Halpern’s t…Read more

161Inexact Knowledge with IntrospectionJournal of Philosophical Logic 38 (2): 179227. 2009.This paper supersedes an ealier version, entitled "A NonStandard Semantics for Inexact Knowledge with Introspection", which appeared in the Proceedings of "Rationality and Knowledge". The definition of token semantics, in particular, has been modified, both for the single and the multiagent case.

90Compositionality Solves Carnap’s ProblemErkenntnis 81 (4): 721739. 2016.The standard relation of logical consequence allows for nonstandard interpretations of logical constants, as was shown early on by Carnap. But then how can we learn the interpretations of logical constants, if not from the rules which govern their use? Answers in the literature have mostly consisted in devising clever rule formats going beyond the familiar what follows from what. A more conservative answer is possible. We may be able to learn the correct interpretations from the standard rules,…Read more

79Consequence Mining: Constans Versus Consequence RelationsJournal of Philosophical Logic 41 (4): 671709. 2012.The standard semantic definition of consequence with respect to a selected set X of symbols, in terms of truth preservation under replacement (Bolzano) or reinterpretation (Tarski) of symbols outside X, yields a function mapping X to a consequence relation ⇒x. We investigate a function going in the other direction, thus extracting the constants of a given consequence relation, and we show that this function (a) retrieves the usual logical constants from the usual logical consequence relations, a…Read more

76Logical Constants, or How to use Invariance in Order to Complete the Explication of Logical ConsequencePhilosophy Compass 9 (1): 5465. 2014.The problem of logical constants consists in finding a principled way to draw the line between those expressions of a language that are logical and those that are not. The criterion of invariance under permutation, attributed to Tarski, is probably the most common answer to this problem, at least within the semantic tradition. However, as the received view on the matter, it has recently come under heavy attack. Does this mean that the criterion should be amended, or maybe even that it should be …Read more

45Carnap's criterion of logicalityIn Pierre Wagner (ed.), Carnap's Logical Syntax of Language, Palgravemacmillan. 2009.Providing a principled characterization of the distinction between logical and nonlogical expressions is a longstanding issue in the philosophy of logic. In the Logical Syntax of Language, Carnap proposes a syntactic solution to this problem, which aims at grounding the claim that logic and mathematics are analytic. Roughly speaking, his idea is that logic and mathematics correspond to the largest part of science for which it is possible to completely specify by "syntactic" means which sentence…Read more

43Since the groundbreaking contributions of M. Dummett (Dummett 1978), it is widely recognized that antirealist principles have a critical impact on the choice of logic. Dummett argued that classical logic does not satisfy the requirements of such principles but that intuitionistic logic does. Some philosophers have adopted a more radical stance and argued for a more important departure from classical logic on the basis of similar intuitions. In particular, J. Dubucs and M. Marion (?) and (Dubuc…Read more

31Modal logic and invarianceJournal of Applied NonClassical Logics 18 (23): 153173. 2008.Consider any logical system, what is its natural repertoire of logical operations? This question has been raised in particular for firstorder logic and its extensions with generalized quantifiers, and various characterizations in terms of semantic invariance have been proposed. In this paper, our main concern is with modal and dynamic logics. Drawing on previous work on invariance for firstorder operations, we find an abstract connection between the kind of logical operations a system uses and…Read more

29Invariance and Definability, with and without EqualityNotre Dame Journal of Formal Logic 59 (1): 109133. 2018.The dual character of invariance under transformations and definability by some operations has been used in classical works by, for example, Galois and Klein. Following Tarski, philosophers of logic have claimed that logical notions themselves could be characterized in terms of invariance. In this article, we generalize a correspondence due to Krasner between invariance under groups of permutations and definability in L∞∞ so as to cover the cases that are of interest in the logicality debates, g…Read more

28Version of March 05, 2007. An extended abstract of the paper appeared in the Proceedings of the 2006 Prague Colloquium on "Reasoning about Vagueness and Uncertainty".

28Tonk Strikes BackAustralasian Journal of Logic 3 3344. 2005.What is a logical constant? In which terms should we characterize the meaning of logical words like “and”, “or”, “implies”? An attractive answer is: in terms of their inferential roles, i.e. in terms of the role they play in building inferences.More precisely, we favor an approach, going back to Dosen and Sambin, in which the inferential role of a logical constant is captured by a double line rule which introduces it as reflecting structural links.Rulebased characterizations of logical constant…Read more

26Metacognitive perspectives on unawareness and uncertaintyIn Michael Beran, Johannes Brandl, Josef Perner & Joëlle Proust (eds.), The Foundations of Metacognition, Oxford University Press. pp. 322. 2012.

23Carnap’s Problem for Modal LogicReview of Symbolic Logic 129. forthcoming.We take Carnap’s problem to be to what extent standard consequence relations in various formal languages fix the meaning of their logical vocabulary, alone or together with additional constraints on the form of the semantics. This paper studies Carnap’s problem for basic modal logic. Setting the stage, we show that neighborhood semantics is the most general form of compositional possible worlds semantics, and proceed to ask which standard modal logics (if any) constrain the box operator to be in…Read more

23Margins for error in contextIn G. Carpintero & M. Koelbel (eds.), Relative Truth, Oxford University Press. pp. 103107. 2008.

22Forthcoming in S. Artemov and R. Parikh, Proceedings of the ESSLLI 2006 Workshop on Rationality and Knowledge.

15L'objet propre de la logiqueLes Etudes Philosophiques 97 (2): 259. 2011.La logique est une théorie normative du raisonnement, qui vise à caractériser la classe des arguments déductifs valides en déterminant si la conclusion est conséquence logique des prémisses. Mais, selon la définition sémantique devenue classique, la caractérisation de la relation de conséquence logique dépend ellemême de la caractérisation de la classe des mots logiques, ces mots qui, comme « non », « et », « tous » ou « certains » servent à articuler nos raisonnements. J’examine dans cet artic…Read more

15Weighted averaging, Jeffrey conditioning and invarianceTheory and Decision 85 (1): 2139. 2018.Jeffrey conditioning tells an agent how to update her priors so as to grant a given probability to a particular event. Weighted averaging tells an agent how to update her priors on the basis of testimonial evidence, by changing to a weighted arithmetic mean of her priors and another agent’s priors. We show that, in their respective settings, these two seemingly so different updating rules are axiomatized by essentially the same invariance condition. As a byproduct, this sheds new light on the q…Read more

15Independence and gamesPhilosophia Scientiae 9 (2): 295304. 2005.Hintikka and Sandu have developed IF logic as a genuine alternative to classical firstorder logic : liberalizing dependence schemas between quantifiers, IF would carry out all the ideas already underlying classical logic. But they are alternatives to Hintikka’s gametheoretic approach; one could use instead Henkin quantifiers. We will present here some arguments of both technical and philosophical nature in favor of IF. We will show that its notion of independence, once extended to connectives,…Read more

15Preuves et jeux sémantiquesPhilosophia Scientiae 8 (2): 105123. 2004.Hintikka makes a distinction between two kinds of games: truthconstituting games and truthseeking games. His wellknown gametheoretical semantics for firstorder classical logic and its independencefriendly extension belongs to the first class of games. In order to ground Hintikka’s claim that truthconstituting games are genuine verification and falsification games that make explicit the language games underlying the use of logical constants, it would be desirable to establish a substantial …Read more

11Compositionality and MolecularismIn Gerhard Schurz, Edouard Machery & Markus Werning (eds.), Applications to Linguistics, Psychology and Neuroscience, De Gruyter. pp. 4162. 2005.

7Les avatars quiniens de l'analyticitéArchives de Philosophie 4 (4): 549562. 2008.Quine est célèbre pour sa critique de la notion d’analyticité, mais il en a également proposé des substituts définissables en termes behavioristes. Cet article examine la question de savoir si de tels substituts peuvent ou non jouer un rôle épistémologique, en les comparant avec des tentatives récentes de réhabilitation de l’a priori. Il apparaît que la caractérisation de ce qu’est une définition acceptable en termes behavioristes est cruciale, et qu’un élargissement de la classe des comportemen…Read more

Deflationary Truth Is a Logical NotionIn Gabriele Pulcini & Mario Piazza (eds.), Truth, Existence and Explanation, Springer Verlag. 2018.

Du point de vue logique est le premier ouvrage philosophique de Quine et peutêtre son plus important. Il rassemble des articles fondamentaux, en philosophie de la logique épistémologie, ontologie et philosophie du langage. Le lecteur pourra y découvrir l’ensemble des enjeux philosophiques de l’œuvre de Quine. Le livre contient notamment « Sur ce qu’il y a », texteclé de la réflexion ontologique contemporaine « Deux dogmes de l’empirisme », qui a suscité un grand nombre de discussions en philos…Read more

La logique est un compagnon naturel de la philosophie. Qu’estce qu’un raisonnement correct? Qu’estce qu’une preuve? Peuton définir le concept de vérité? Que faire face aux paradoxes? Ces questions sont débattues par les philosophes depuis l’Antiquité; et la logique moderne, usant de langages formels, développe une analyse rigoureuse de ces concepts les plus fondamentaux.Les onze textes classiques réunis ici proposent un retour réflexif sur cette discipline et sur la signification philosophiqu…Read more
Université Paris Nanterre

Université Paris NanterreAssistant Professor
University of Paris 1 PanthéonSorbonne
Department for Teaching and Research in Philosophy (UFR10)
PhD, 2006