Université Paris Nanterre
  •  863
    Logicality and Invariance
    Bulletin of Symbolic Logic 14 (1): 29-68. 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.
  •  205
    Vagueness, uncertainty and degrees of clarity
    with Paul Égré
    Synthese 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 higher-order vagueness. We first examine the consequences of the notion of intransitivity of indiscriminability for higher-order vagueness, and compare several accounts of vagueness as inexact or imprecise knowledge, namely Williamson’s margin for error semantics, Halpern’s t…Read more
  •  161
    Inexact Knowledge with Introspection
    Journal of Philosophical Logic 38 (2): 179-227. 2009.
    This paper supersedes an ealier version, entitled "A Non-Standard 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 multi-agent case.
  •  90
    Compositionality Solves Carnap’s Problem
    Erkenntnis 81 (4): 721-739. 2016.
    The standard relation of logical consequence allows for non-standard 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
  •  79
    Consequence Mining: Constans Versus Consequence Relations
    Journal of Philosophical Logic 41 (4): 671-709. 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
  •  76
    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
  •  45
    Carnap's criterion of logicality
    In Pierre Wagner (ed.), Carnap's Logical Syntax of Language, Palgrave-macmillan. 2009.
    Providing a principled characterization of the distinction between logical and non-logical 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
  •  43
    Since the ground-breaking contributions of M. Dummett (Dummett 1978), it is widely recognized that anti-realist 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
  •  31
    Modal logic and invariance
    Journal of Applied Non-Classical Logics 18 (2-3): 153-173. 2008.
    Consider any logical system, what is its natural repertoire of logical operations? This question has been raised in particular for first-order 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 first-order operations, we find an abstract connection between the kind of logical operations a system uses and…Read more
  •  29
    Invariance and Definability, with and without Equality
    Notre Dame Journal of Formal Logic 59 (1): 109-133. 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
  •  28
    Version 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".
  •  28
    Tonk Strikes Back
    with Benjamin Simmenauer
    Australasian Journal of Logic 3 33-44. 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.Rule-based characterizations of logical constant…Read more
  •  26
    Metacognitive perspectives on unawareness and uncertainty
    with Paul Egré
    In Michael Beran, Johannes Brandl, Josef Perner & Joëlle Proust (eds.), The Foundations of Metacognition, Oxford University Press. pp. 322. 2012.
  •  23
    Carnap’s Problem for Modal Logic
    Review of Symbolic Logic 1-29. 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
  •  23
    Margins for error in context
    with Paul Egré
    In G. Carpintero & M. Koelbel (eds.), Relative Truth, Oxford University Press. pp. 103--107. 2008.
  •  22
    Forthcoming in S. Artemov and R. Parikh, Proceedings of the ESSLLI 2006 Workshop on Rationality and Knowledge.
  •  18
  •  15
    L'objet propre de la logique
    Les 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 elle-même 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
  •  15
    Weighted averaging, Jeffrey conditioning and invariance
    Theory and Decision 85 (1): 21-39. 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 by-product, this sheds new light on the q…Read more
  •  15
    Independence and games
    Philosophia Scientiae 9 (2): 295-304. 2005.
    Hintikka and Sandu have developed IF logic as a genuine alternative to classical first-order logic : liberalizing dependence schemas between quantifiers, IF would carry out all the ideas already underlying classical logic. But they are alternatives to Hintikka’s game-theoretic 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
  •  15
    Preuves et jeux sémantiques
    Philosophia Scientiae 8 (2): 105-123. 2004.
    Hintikka makes a distinction between two kinds of games: truthconstituting games and truth-seeking games. His well-known game-theoretical semantics for first-order classical logic and its independence-friendly extension belongs to the first class of games. In order to ground Hintikka’s claim that truth-constituting 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
  •  11
    Compositionality and Molecularism
    In Gerhard Schurz, Edouard Machery & Markus Werning (eds.), Applications to Linguistics, Psychology and Neuroscience, De Gruyter. pp. 41-62. 2005.
  •  7
    Les avatars quiniens de l'analyticité
    Archives de Philosophie 4 (4): 549-562. 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
  •  6
    Preuves et jeux sémantiques
    Philosophia Scientae 8 105-123. 2004.
  •  4
    The philosophy of science. A companion (edited book)
    Oxford University Press. 2018.
  • Comptes rendus. Philosophes et la science, Les
    Archives de Philosophie 66 (4): 708-709. 2003.
  • Deflationary Truth Is a Logical Notion
    with H. Galinon
    In Gabriele Pulcini & Mario Piazza (eds.), Truth, Existence and Explanation, Springer Verlag. 2018.
  • Du Point de Vue Logique: Neuf Essais Logico-Philosophiques
    with Willard Von Orman Quine, C. Alsaleh, B. Ambroise, S. Bozon, and M. Cozic
    Vrin. 2003.
    Du point de vue logique est le premier ouvrage philosophique de Quine et peut-être 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 », texte-clé de la réflexion ontologique contemporaine « Deux dogmes de l’empirisme », qui a suscité un grand nombre de discussions en philos…Read more
  • Willard von Orman Quine
    with Sandra Laugier, Layla RAÏD, Fabrice Pataut, and Roger Schmit
    Archives de Philosophie 71 (4). 2008.
  • La logique est un compagnon naturel de la philosophie. Qu’est-ce qu’un raisonnement correct? Qu’est-ce qu’une preuve? Peut-on 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