The main aim of our paper is to implement Leibniz's analysis of the conditional right in the framework of a dialogical approach to Public Announcement Logic. According to our view, on one hand: PAL furnishes a dynamic epistemic operator which models communication exchange between different agents that seems to be very close to Leibniz understanding of the dynamics between the truth of a proposition and the knowledge of the truth of that proposition (Leibniz calls the latter certification of its truth); (...) on the other hand, the dialogical approach provides a semantics for the dynamic epistemic operator in the context of conditional right by means of which: (i) the exchange between agents leading to a public announcement amounts to the (contractual) interaction of commitments of both the benefactor and the beneficiary of a conditional right (ii) the notion of certification is understood as an action, namely as a move where the beneficiary asks the benefactor to stand to his commitments, (iii) some restrictions specific to the logical nature of the head and the tail of the conditional right can be implemented by combining PAL with some features of linear logic within the same theory of meaning. (shrink)

RésuméLa définition de la condition suspensive, telle qu’elle nous est donnée dans l’article 1181 du Code civil français, est aujourd’hui au centre de différents projets de réforme. Si aucun projet de réforme n’a réussi à emporter l’assentiment de tous les juristes, nombre d’entre eux semblent s’accorder sur la nécessité de réformer ce texte—inchangé depuis 1804. Pourquoi un tel consensus sur ce besoin de réécriture de la définition de la condition suspensive mène à une discussion doctrinale où deux positions principales s’opposent? (...) C’est à cette question que nous tâchons de répondre en traquant l’origine de cette scission dans la lettre même du texte dont nous analysons à la fois la structure logique et la signification des termes employés pour sa rédaction. Cette analyse nous permet de mettre en évidence la sémantique ambiguë du terme “incertain”, terme pour lequel nous proposons une analyse logique de sa signification que nous comparons ensuite à celle du terme “inconnu”. (shrink)

In line with [2], [12, 13, 14] carefully studies the Leibnizian notion of suspensive condition—notion that Leibniz sometimes names moral condition. Thiercelin points out Leibniz’ will to provide a rigorous definition of that kind of condition. Leibniz not only establishes a link between the legal notion of condition and the logical notion of condition, but he also grasps the problematic of suspensive condition through its epistemic and dynamic features. In this paper we start from Thiercelin’s reflections about Leibniz’ suspensive condition. (...) Thiercelin’s work offers an inventory of different clauses that a logical conditional must fulfill to capture the legal meaning of suspensive condition. Our aim is to compare such a definition with the Public Announcement operator semantics ([16]) taking advantage of both its model theoretic semantics and its dialogical semantics (introduced for the first time in [5]). We show that the public announcement operator entails the same dynamic and epistemic features than the ones that Leibniz requires with its notion of suspensive condition. (shrink)

Since Plaza [1989], which is most of the time considered as the inaugural paper on announcement logics in public communication contexts, a lot of papers on dynamic epistemic logics have been published. The most famous dynamic epistemic logic is known by the name of PAL (Public Announcement Logic). The logic PAC is an extension of PAL with the common knowledge operator (CG). Soundness and completeness proofs of those logics are presented in van Ditmarsch et al. [2008], in Balbiani et al. (...) [2010] and in de Boer [2007]. Each of them used either a model-theoretic approach or a tableaux calculus. In the present paper, we propose an alternative approach to PAC based on the dialogical framework. (shrink)