This text is an outgrowth of notes prepared by J. Y. Girard for a course at the University of Paris VII. It deals with the mathematical background of the application to computer science of aspects of logic (namely the correspondence between proposition & types). Combined with the conceptual perspectives of Girard's ideas, this sheds light on both the traditional logic material & its prospective applications to computer science. The book covers a very active & exciting research area, & it will (...) be essential reading for all those working in logic & computer science. (shrink)

The hexagon of opposition is an improvement of the square of opposition due to Robert Blanché. After a short presentation of the square and its various interpretations, we discuss two important problems related with the square: the problem of the I-corner and the problem of the O-corner. The meaning of the notion described by the I-corner does not correspond to the name used for it. In the case of the O-corner, the problem is not a wrong-name problem but a no-name (...) problem and it is not clear what is the intuitive notion corresponding to it. We explain then that the triangle of contrariety proposed by different people such as Vasiliev and Jespersen solves these problems, but that we don’t need to reject the square. It can be reconstructed from this triangle of contrariety, by considering a dual triangle of subcontrariety. This is the main idea of Blanché’s hexagon. We then give different examples of hexagons to show how this framework can be useful to conceptual analysis in many different fields such as economy, music, semiotics, identity theory, philosophy, metalogic and the metatheory of the hexagon itself. We finish by discussing the abstract structure of the hexagon and by showing how we can swing from sense to non-sense thinking with the hexagon. (shrink)

This special issue of Logica Universalis (Springer) deals with the relations between logic and religion, broadly conceived. It contains the following articles: Logic and Religion, by Jean-Yves Beziau and Ricardo Silvestre; Thinking Negation in Early Hinduism and Classical Indian Philosophy, by Purushottama Bilimoria; Karma Theory, Determinism, Fatalism and Freedom of Will, by Ricardo Sousa Silvestre; From Logic in Islam to Islamic Logic, by Musa Akrami; Leibniz’s Ontological Proof of the Existence of God and the Problem of Impossible Objects, (...) by Wolfgang Lenzen; A Logical Analysis of the Anselm’s Unum Argumentum (from Proslogion), by Jean-Pierre Desclés; Monotonic and Non-monotonic Embeddings of Anselm’s Proof, by Jacob Archambault; Computer-Assisted Analysis of the Anderson–Hájek Ontological Controversy, by C. Benzmüller, L. Weber and B. Woltzenlogel Paleo. (shrink)

Using methods of abstract logic and the theory of valuation, we prove that there is no paraconsistent negation obeying the law of double negation and such that $\neg(a\wedge\neg a)$ is a theorem which can be algebraized by a technique similar to the Tarski-Lindenbaum technique.

Jean-Yves Strasser The Olympia of Alexandria and the Pancratiast M. Aur. Asklepiades p.421-468 The Alexandrian Olympia are known thanks to inscriptions and especially papyri. The latter mention the olympionikoi, who may have been victors not in the great competition at Pisa, but in the Olympia of the Egyptian city. These competitions, created under Marcus Aurelius, became eiselastikoi under Gallien; they were first celebrated in 268. Like the majority of the great competitions in Egypt, they took place in the (...) winter of even years divisible by four. That was the case already in the 2nd century AD: the first Olympia were organised in 180. In 200, at the time of the sixth celebration, the periodonikes M. Aur. Asklepiades won the Olympia pancration in the presence of Septimius Severus and Caracalla. An inscription at Coptus (I. Portes 88) mentions a hellanodikes of Alexandria: he could have been serving at the time of the seventeenth Olympiad in 244; in 246-247 he had a statue of Sarapis Polieus erected under the prefect of Egypt Valerius Firmus. (shrink)

Ludics [1] is a novel approach to logic—especially proof-theory. The present introduction emphasises foundational issues.For ages, not a single disturbing idea in the area of “foundations”: the discussion is sort of ossified—as if everything had been said, as if all notions had taken their definite place, in a big cemetery of ideas. One can still refresh the flowers or regild the stone, e.g., prove technicalities, sometimes non-trivial; but the real debate is still: this paper begins with an autopsy, the autopsy (...) of the foundational project.Up to say 1900, the realist/dualist approach to science was dominant; during the last century some domains like physics evolved so as to become completely anti-realist; but this evolution hardly concerned logic.By the turn of the XXth century mathematics was jeopardised by paradoxes, the most famous of them being due to Russell. Hilbert's reaction was to focus on consistency. But the reduction of paradoxes—and therefore of foundations—to solely the antinomies is highly questionable: indeed, the typical paradoxical artifacts are secret sharers, objects satisfying the formal definitions but far astray from the intended meaning, typically the Peano “curve” which contradicts our perception of dimension. Fortunately, topology has been able to show that dimension m is not the same as dimension n … but just for a second, forget this and imagine consistent mathematics in which balls in any dimension are homeomorphic: what a disaster! This exclusive focus on consistency—not to speak of the strategic failure of the Programme—should explain why logic, especially foundations lost contact with other sciences during last century. (shrink)

Many-valued logics are standardly defined by logical matrices. They are truth-functional. In this paper non truth-functional many-valued semantics are presented, in a philosophical and mathematical perspective.

This is a collection of new investigations and discoveries on the theory of opposition (square, hexagon, octagon, polyhedra of opposition) by the best specialists from all over the world. The papers range from historical considerations to new mathematical developments of the theory of opposition including applications to theology, theory of argumentation and metalogic.

Jean-Yves Béziau Abstract In this paper I relate the story about the new rising of the square of opposition: how I got in touch with it and started to develop new ideas and to organize world congresses on the topic with subsequent publications.

New commentary on Hadrian’s second letter to Dionysiac artists. A thorough study of the text structure and vocabulary reveals that the emperor has not always altered the schedule of Greek games. His main concern is to insert the competitions he himself has created and to avoid conflicts between the cities. He certainly didn’t offend the susceptibilities of the Greeks, but he probably also resisted numerous requests. He has favoured considerably Athens. The understanding of the end of the text can be (...) improved. The dates provided by Hadrian in the solar Julian calendar must be reinterpreted in light of a lunar calendar. (shrink)

Jean-Jacques Rousseau est l'auteur de l'entrée "économie politique" dans l'Encyclopédie en 1755. A ce titre, il aurait pu être l'un des fondateurs de cette discipline. Pourtant, la définition qu'il en donne est à l'encontre de la pensée libérale des physiocrates, puis des classiques, et constitue une véritable "anti-économique". En hypertrophiant le rôle de l'Etat et en niant l'intérêt personnel, Rousseau est au contraire l'un des pères du socialsme. En niant la liberté humaine, il nie aussi l'existence de choix éthiques.

Linear logic, introduced in 1986 by J.-Y. Girard, is based upon a fine grain analysis of the main proof-theoretical notions of logic. The subject develops along the lines of denotational semantics, proof nets and the geometry of interaction. Its basic dynamical nature has attracted computer scientists, and various promising connections have been made in the areas of optimal program execution, interaction nets and knowledge representation. This book is the refereed proceedings of the first international meeting on linear logic held at (...) Cornell University, in June 1993. Survey papers devoted to specific areas of linear logic, as well as an extensive general introduction to the subject by J.-Y. Girard, have been added, so as to make this book a valuable tool both for the beginner and for the advanced researcher. (shrink)

The paper extends a result in Dutta and Ray's (1989) theory of constrained egalitarianism initiated by relying on the concept of proportionate rather than absolute equality. We apply this framework to redistributive systems in which what the individuals get depends on what they receive or pay qua members of generally overlapping groups. We solve the constrained equalization problem for this class of models. The paper ends up comparing our solution with the alternative solution based on the Shapley value, which has (...) been recommended in some distributive applications. (shrink)

We present a single sequent calculus common to classical, intuitionistic and linear logics. The main novelty is that classical, intuitionistic and linear logics appear as fragments, i.e. as particular classes of formulas and sequents. For instance, a proof of an intuitionistic formula A may use classical or linear lemmas without any restriction: but after cut-elimination the proof of A is wholly intuitionistic, what is superficially achieved by the subformula property and more deeply by a very careful treatment of structural rules. (...) This approach is radically different from the one that consists in “changing the rule of the game” when we want to change logic, e.g. pass from one style of sequent to another: here, there is only one logic, which—depending on its use—may appear classical, intuitionistic or linear. (shrink)

qui y recense ses nombreuses victoires. Une brève histoire des choraules et de leur participation aux concours peut ainsi être esquissée : malgré sa popularité, surtout en Occident, la discipline n'a été acceptée que tardivement dans les concours, et aux Pythia sans doute seulement à la fin du Ier siècle. Un premier appendice évoque rapidement les catalogues du personnel cultuel conservés à Olym- pie ; un second établit le texte d'une inscription de Nîmes (IG XIV 2499), où l'on doit reconnaître (...) un acte de l'association universelle des artistes dionysiaques. (shrink)

Le pancratiaste périodonique Markos Aurèlios Dèmostratos Damas de Sardes est connu par de nombreux témoignages trouvés dans sa patrie, à Rome, à Éphèse, à Delphes et en Egypte. Leur réexamen permet de reconstruire avec précision la carrière du champion, comme d'éclairer certains points de l'histoire des concours qu'il a remportés. Deux inscriptions d'Éphèse qui lui ont été rapportées ne doivent sans doute pas l'être. On peut proposer de nouveaux suppléments aux palmarès de Sardes et de Delphes ; un autre texte (...) delphique est identifié comme une nouvelle liste chronologique des victoires de Dèmostratos Damas. Le pancratiaste, dont le floruit se situe sous le règne de Marc Aurèle, a brillé en fin de carrière dans la boxe. Les statues dont on a retrouvé les bases ont été érigées essentiellement après sa carrière sportive, lorsqu'il exerce, sous Septime Sévère, les plus hautes charges au sein de l'association des athlètes. (shrink)

Universal logic is to logic what universal algebra is to algebra. It is not a specific system of logic that would apply to everything but a general theory of all existing and possible logics. This new field has been slowly emerging through the new directions of research in logic of the past decades and the name was coined 15 years ago. In the Spring of 2005 was organized in Montreux, Switzerland, the First World Congress on Universal Logic. This exciting event (...) gathered more than 200 people from about 40 different countries. Many famous logicians were present there, such as Dov Gabbay, Krister Segerberg, Saul Kripke, Michael Dunn, Jouko Väännänen. Most of the papers in this book arose from talks - and discussions that follow - presented during this event. They are concerned with philosophical and historical approaches discussing the basic concepts of logic and reflecting the meaning of a universal approach to logic, the development and elaboration of general tools in order to construct frameworks useful for studying classes of logics, applications of logics to concrete problems through the universal perspective. (shrink)

This paper aims to shed new light on Hegel’s rather problematic statements about Asian thinking and Chinese philosophy by disclosing the Orientalist antecedents found in Kant’s anthropological works. First, the notion of Orientalism will be defined with reference to Orientalism and “Orientalism Reconsidered” by Edward Said. Second, an exploration of Kant’s anthropological research will show that this constituted the turning point in the Western Orientalist perception of China which had a strong influence on Hegel Finally, it will be claimed that (...) Hegel’s Orientalist perception of China rests on a definition of culture as the expression of the “spirit of a people” that has recently been revised by contemporary post-colonial anthropologists. (shrink)

In this paper we address some central problems of combination of logics through the study of a very simple but highly informative case, the combination of the logics of disjunction and conjunction. At first it seems that it would be very easy to combine such logics, but the following problem arises: if we combine these logics in a straightforward way, distributivity holds. On the other hand, distributivity does not arise if we use the usual notion of extension between consequence relations. (...) A detailed discussion about this phenomenon, as well as some possible solutions for it, are given. (shrink)

of implication and generalization rules have a close relationship, for which there is a key idea for clarifying how they are connected: varying objects. Varying objects trace how generalization rules are used along a demonstration in an axiomatic calculus. Some ways for introducing implication and for generalization are presented here, taking into account some basic properties that calculi can have.

In this paper we discuss the distinction between sentence and proposition from the perspective of identity. After criticizing Quine, we discuss how objects of logical languages are constructed, explaining what is Kleene’s congruence—used by Bourbaki with his square—and Paul Halmos’s view about the difference between formulas and objects of the factor structure, the corresponding boolean algebra, in case of classical logic. Finally we present Patrick Suppes’s congruence approach to the notion of proposition, according to which a whole hierarchy of congruences (...) leads to different kinds of objects. (shrink)

Rarely is the problem of the diversity of languages taken into account whenever population groups are formed into States. When the problem does come up, it is later, in a primarily political context which tries to find political solutions, such as we may presently see them in Canada or in Belgium for instance. These solutions are few and they deal with situations that may contain a host of nuances.Certain countries have chosen a vehicular language while keeping their local languages: the (...) common language in the USSR is the language of one of its republics. In Senegal it is French, which is of a totally foreign origin but has the advantage of avoiding the rivalry existing among the native languages, and it also has a place within the international community. Other countries have accepted as official languages the different languages spoken within its borders. Thus Switzerland is officially tri-lingual (French, German, Italian), giving legal status to what somewhere else may simply be an accepted fact. Many Alsatians speak three languages (Alsatian, French, German). As far as it concerns countries with a strong linguistic heterogeneity, whether it be their history or their size making for a centralizing policy, they have adopted, with the resulting neglect of all others, the language or the idiom of the region which was politically or culturally the dominant one at the time of their unification. Pekinese has been extended to all of China, Florentine to Italy, Hindi to India. Some original combinations can be found: in Israel Jewish immigrants who came from more than seventy different countries, have again taken up the nation's old cultural and religious language, which had been out of use for two thousand years, and have placed it on equal footing with Arabic spoken by the local population, while English is being used for international relations. (shrink)

1 What are the features of a paraconsistent negation? Since paraconsistent logic was launched by da Costa in his seminal paper [4], one of the fundamental problems has been to determine what exactly are the theoretical or metatheoretical properties of classical negation that can have a unary operator not obeying the principle of noncontradiction, that is, a paraconsistent operator. What the result presented here shows is that some of these properties are not compatible with each other, so that in constructing (...) a paraconsistent negation as close as possible to classical negation, we have to make a choice among classical properties compatible with the idea of paraconsistency. In particular, there is no paraconsistent negation more classical than all the others. (shrink)

Goffi and Roux are interested in what makes some thought experiments work, while others do not work. They do not attempt to draw an a priori line between two types of thought experiments, but rather ask the following question: inasmuch as thought experiments are arguments, and notwithstanding the fact that some of them might involve the contemplation of an imaginary scenario, how is it that some of them work, while others do not? Taking inspiration from a counterfactual thought experiment presented (...) by Nicholas Rescher, they treat thought experiments as argumentative procedures resembling tests of consistency, which invite the experimenter to seek the weakest link in her body of beliefs. Equipped with this method, they examine two well-known successful thought experiments (Galileo’s two bodies strapped together, and Thomson’s violinist) and discuss Mach’s notion of thought experiments. Thus they reach the hypothesis that successful thought experiments respect the three following conditions: they do not deal with things, but with beliefs; they mobilise a set of beliefs shared by the interlocutors; and this set of beliefs has a hierarchical structure. Using once again examples written at different periods and taken from various disciplines (Descartes’ receding bodies, Aristotle’s weaving shuttles), Goffi and Roux argue that each of those conditions is individually necessary for a thought experiment to work. They finally conclude on the limits and consequences of their approach. (shrink)

t.l. Introduction à une anthropologie philosophique.

Sont réexaminées plusieurs inscriptions agonistiques d’Athènes. 1. Le texte IG II3 4, 624 pour un héraut périodonique doit certainement être attribué à Valerius Eklektos de Sinope, déjà connu par un long texte d’Athènes, une base à Olympie et un piédestal retrouvé à Delphes resté inédit et publié ici. L’ensemble permet de reconstituer le parcours d’un artiste hors norme connu par quatre textes gravés à des moments différents de sa carrière. 2. Les fragments IG II3 4, 616 et 617 appartiennent au (...) même palmarès du second tiers du IIIe s. et peuvent vraisemblablement être reliés l’un à l’autre. Si IG II3 4, 618 ne provient pas du même monument, il pourrait lui être en revanche contemporain. 3. La base SEG 58, 185 honore non un agonothète mais un épistate, dont sont vantés les succès lors d’une longue carrière. 4. IG II² 2772 est une dédicace funéraire faite par un boxeur et xystarque pour un parent ou un ami. (shrink)

This paper introduces the special issue on Logic and Religion of the journal Logica Universalis (Springer). The issue contains the following articles: Logic and Religion, by Jean-Yves Beziau and Ricardo Silvestre; Thinking Negation in Early Hinduism and Classical Indian Philosophy, by Purushottama Bilimoria; Karma Theory, Determinism, Fatalism and Freedom of Will, by Ricardo Sousa Silvestre; From Logic in Islam to Islamic Logic, by Musa Akrami; Leibniz’s Ontological Proof of the Existence of God and the Problem of Impossible Objects, (...) by Wolfgang Lenzen; A Logical Analysis of the Anselm’s Unum Argumentum (from Proslogion), by Jean-Pierre Desclés; Monotonic and Non-monotonic Embeddings of Anselm’s Proof, by Jacob Archambault; Computer-Assisted Analysis of the Anderson–Hájek Ontological Controversy, by C. Benzmüller, L. Weber and B. Woltzenlogel Paleo. (shrink)

Le but de cet article est, à travers l’histoire des relations entre science et philosophie du temps, de retracer l’archéologie épistémologique du temps pensé comme progrès linéaire. Nous voudrions montrer : 1. que la pensée du « temps » évolue avec le temps, 2. que cette évolution peut se lire en même temps en science et en philosophie sans qu’il soit nécessaire d opposer l’une à l’autre, 3. qu’elle n’est pas réductible à une opposition entre réversibilité ou irréversibilité ; 4. (...) qu’elle s’exprime à travers trois « métaphores épistémiques » distinctes : cercle, ligne ou réseau — à l’intérieur desquels l’antinomie entre conception « idéaliste » ou « réaliste » de la temporalité ne cesse de se rejouer ; 5. qu’il est possible de dépasser cette antinomie par l’idée régulatrice d’une fonction cosmologique de la temporalité définie comme la forme de l’interaction entre événements physiques et lois naturelles. (shrink)