Yves Bouchard

Knowledge representation is one way to exploit expertise in a given domain by logical means. But, what kind of knowledge does one acquire from an inference (or inference on a query result over a knowledge base)? Such a question may appear awkward since the answer seems so obvious: from an inference, one simply acquires knowledge. This is undoubtedly the case when only one type of knowledge (for instance, expert knowledge) is involved in an inference. What if several types of knowledge are involved? What type of knowledge can one deduce from a plurality of knowledge types? I claim that reasoning with different knowledge concepts requires a fine-grained representation of knowledge in which every knowledge type finds a singular expression in order to avoid some epistemic equivocity associated with a coarse-grained representation of knowledge. In the first part of the paper, I revisit the Muddy Children Puzzle, which usually serves to illustrate common knowledge in dynamic epistemic logic. I try to show that this problem also shows some sort of epistemic equivocity between concepts of knowledge and, consequently, that the problem calls for some epistemological refinements concerning the representation of the types of knowledge at play in an inference. In the second part, I address this issue from a semantic point of view, and I develop a fragment of epistemic logic capable of providing a solution to the problem of epistemic equivocity.

This paper presents an epistemological framework capable of addressing the opposition between indigenous knowledge and scientific knowledge, an opposition widespread in anthropology especially in relation to the problem of sustainable development. In the first part of the paper, we provide a contextualist framework that satisfies two constraints: a priori neutrality with respect to forms, or types, of knowledge, and explicitness of the conditions with respect to the possibility of knowledge transfer. In the second part, we apply the framework to the specific case of Northern Algonquian knowledge. By means of the framework, we investigate and make explicit the underlying epistemic standard at play by identifying the conditions under which particular beliefs are qualified as knowledge in the Northern Algonquian context.

Un calcul logique, au sens large, est une méthode de résolution appliquée au traitement d'une structure propositionnelle. Les propositions constituant cette structure peuvent aussi bien être des expressions d'une langue naturelle (comme le français) que des expressions d'un langage formalisé (comme l'arithmétique), liées entre elles par une dépendance de nature fonctionnelle. Cet ouvrage constitue une introduction à deux outils de calcul en logique du premier ordre, soit le calcul en arbres de consistance et le calcul en déduction naturelle. La première partie, centrée sur la notion de structure propositionnelle, expose les concepts, les objets et les méthodes propres à la logique propositionnelle. Dans la deuxième partie, la logique propositionnelle est étendue à la logique prédicative au moyen de la quantification et de concepts caractéristiques d'un langage du premier ordre. Les deux outils de calcul sont ensuite enrichis de manière à pouvoir traiter des fonctions propositionnelles, soit des prédicats du premier ordre.De nombreux exemples et exercices, accompagnés de leurs solutions, aideront l'étudiant à progresser vers des calculs toujours plus complexes et à raffiner ses méthodes de calcul logique.

Christoph Jäger has argued that Dretske’s information-based account of knowledge is committed to both knowledge and information closure under known entailment. However, in a reply to Jäger, Dretske defended his view on the basis of a discrepancy between the relation of information and the relation of logical implication. This paper shares Jäger’s criticism that Dretske’s externalist notion of information implies closure, but provides an analysis based on different grounds. By means of a distinction between two perspectives, the mathematical perspective and the epistemological perspective, I present, in the former, a notion of logical implication that is compatible with the notion of information in the mathematical theory of information, and I show how, in the latter, Dretske’s logical reading of the closure principle is incompatible with his information-theoretic epistemological framework.

I establish and I explore a parallel between two important analogies in Wittgenstein’s remarks on knowledge and certainty, and two characteristic features of Dretske’s information-theoretic model of knowledge. My claim is that the analogical opposition (a static/dynamic type of opposition) behind the axis/hinge and the riverbed/flux-of-the-waters analogies finds a counterpart in Dretske’s perspective with the opposition between information and conditions of the channel of communication. This comparative analysis puts into light the epistemic functions at stake in Wittgenstein’s analogies and in Dretske’s framework, as well as two common conclusions that both Wittgenstein and Dretske share about the status and the scope of sceptical doubts.

In this paper, I defend a contextualist reading of the KK-thesis. In the first part, I present the general problem and I contrast three concepts of knowledge with respect to the KK-thesis, (Hintikka, Lemmon, and Williamson) that all rely on a univocal interpretation of the K-predicate. In the second part, I provide a contextualist framework based upon an indexical interpretation of the K-predicate and the notion of epistemic context. I show how this framework can integrate different concepts of knowledge, and how it highlights the crucial significance of the KK-thesis for epistemology.

Cette etude a pour but d'etablir que l'epistemologie developpee par Kant dans la Critique de la raison pure est holiste. Pour ce faire, nous construirons, dans la Partie I, un cadre conceptuel permettant de definir ce qui peut caracteriser un systeme holiste. La Partie II sera consacree a l'examen de la Critique de la raison pure selon ce cadre conceptuel. Enfin, apres avoir montre que les developpements epistemologiques majeurs de la premiere Critique satisfont les conditions du cadre holiste, nous mettrons en relief, dans la Partie III, les fondements et les implications de la forme de holisme particuliere a l'epistemologie kantienne. Au terme de cette etude, la Theorie des elements de la Critique de la raison pure manifestera une unite fondamentale faisant de l'Esthetique, de l'Analytique et de la Dialectique trois moments d'un mouvement regressif de plus en plus totalisant et dont le point d'achevement se trouve dans l'analyse de l'ideal transcendantal.

In this paper, I show the complementarity of foundationalism and coherentism with respect to any efficient system of beliefs by means of a distinction between two types of proposition drawn from an analogy with an axiomatic system. This distinction is based on the way a given proposition is acknowledged as true, either by declaration (F-proposition) or by preservation (C-proposition). Within such a perspective, i.e., epistemological complementarism, not only can one see how the usual opposition between foundationalism and coherentism is irrelevant, but furthermore one can appreciate the reciprocal relation between these two theories as they refer to two separate epistemological functions involved in the dynamics of constituting and expanding an epistemic system.

I argue in favor of the principle of deductive closure. I provide a characterization of the notion of epistemic context in terms of presuppositions in order to show how one can preserve deductive closure by limiting its applicability to a given epistemic context. This analysis provides also a redefinition of relevant alternatives from an epistemological point of view, that avoids any appeal to a counter-factual interpretation of relevance. In that perspective, relevance is conceived as a presuppositional quality. In regard to the debate with the skeptic, it is shown that her argument relies upon a context shift that compromises deductive closure because it alters the presuppositions at play. Finally, deductive closure is not only vindicated but is acknowledged as a contextual marker in the sense that a failure of deductive closure indicates a context shift. © 2012 Elsevier B.V., All rights reserved.

The general principle of epistemic closure stipulates that epistemic properties are transmissible through logical means. According to this principle, an epistemic operator, say ε, should satisfy any valid scheme of inference, such as: if ε(p entails q), then ε(p) entails ε(q). The principle of epistemic closure under known entailment (ECKE), a particular instance of epistemic closure, has received a good deal of attention since the last thirty years or so. ECKE states that: if one knows that p entails q, and she knows that p, then she knows that q. It is widely accepted that ECKE constitutes an important piece of the skeptical argument, but the acceptance of an unrestricted version of ECKE is still a matter of debate. On the side of the defenders of ECKE, one finds Stine (1976), Brueckner (1985), Vogel (1990), and Feldman (1995). Others proposed a refutation or a limitation of the principle, like Dretske (1970), Nozick (1981), Hales (1995), Williams (1996), and Sosa (1999). As it turns out, the relevant alternatives view (RAV) elaborated by Dretske, which restricts the scope of ECKE, has been discussed extensively and acknowledged as one of the most important contributions. There is nonetheless a major unsolved difficulty pertaining to Dretske-RAV: the notion of relevant alternatives is defined in such a way that it is bounded by counterfactual possibilities. This ontological import leaves open the door to the skeptic. Some have tried to give more precision to this notion, like Stine (1976), who appealed to a Gricean approach to define relevant alternatives in conversational contexts. My proposal is in accordance with the gist of Dretske’s strategy, i.e. to restrict the validity of ECKE, and I claim that in order to escape the difficulties inherent to RAV one has to introduce a more robust notion, the notion of epistemic context. Epistemic contexts are a subclass of propositional contexts. In that perspective, the closure property is expressed in terms of a property of a relation between epistemic contexts. ECKE holds when and only when either the epistemic context of the premisses is the same as the epistemic context of the conclusion, or the epistemic context change between the premisses and the conclusion is permissible. Permissibility of epistemic context change is a function of consistency. By means of this epistemic context approach, I will show that: (1) epistemic contexts are defined by basic propositions (unchallenged justified beliefs), (2) ECKE holds only under very specific constraints, and (3) the skeptical argument involves a non-permissible change of epistemic context and, by the same token, cannot rely upon ECKE.