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)

Recently, Lincoln, Scedrov and Shankar showed that the multiplicative fragment of second order intuitionistic linear logic is undecidable, using an encoding of second order intuitionistic logic. Their argument applies to the multiplicative-additive fragment, but it does not work in the classical case, because second order classical logic is decidable. Here we show that the multiplicative-additive fragment of second order classical linear logic is also undecidable, using an encoding of two-counter machines originally due to Kanovich. The faithfulness of this encoding is (...) proved by means of the phase semantics. (shrink)

t.l. Introduction à une anthropologie philosophique.

These lectures on logic, more specifically proof theory, are basically intended for postgraduate students and researchers in logic. The question at stake is the nature of mathematical knowledge and the difference between a question and an answer, i.e., the implicit and the explicit. The problem is delicate mathematically and philosophically as well: the relation between a question and its answer is a sort of equality where one side is ``more equal than the other'': one thus discovers essentialist blind spots. Starting (...) with Godel's paradox --so to speak, the incompleteness of answers with respect to questions--the book proceeds with paradigms inherited from Gentzen's cut-elimination. Various settings are studied: sequent calculus, natural deduction, lambda calculi, category-theoretic composition, up to geometry of interaction, all devoted to explicitation, which eventually amounts to inverting an operator in a von Neumann algebra. Mathematical language is usually described as referring to a preexisting reality. Logical operations can be given an alternative procedural meaning: typically, the operators involved in GoI are invertible, not because they are constructed according to the book, but because logical rules are those ensuring invertibility. Similarly, the durability of truth should not be taken for granted: one should distinguish between imperfect and perfect modes. The procedural explanation of the infinite thus identifies it with the unfinished, i.e., the perennial. But is perenniality perennial? This questioning yields a possible logical explanation for algorithmic complexity. This highly original course on logic by one of the world's leading proof theorists challenges mathematicians, computer scientists, physicists, and philosophers to rethink their views and concepts on the nature of mathematical knowledge in an exceptionally profound way. (shrink)

Go back to An-fang, the Peace Square at An-Fang, the Beginning Place at An-Fang, where all things start (… ) An-Fang was near a city, the only living city with a pre-atomic name (… ) The headquarters of the People Programmer was at An-Fang, and there the mistake happened: A ruby trembled. Two tourmaline nets failed to rectify the laser beam. A diamond noted the error. Both the error and the correction went into the general computer. Cordwainer SmithThe Dead Lady (...) of Clown Town, 1964. (shrink)

Three years of work with more than twenty scientists and high-level specialists: here are revealed the modern proofs of the existence of God. For almost four centuries, from Copernicus to Freud via Galileo and Darwin, scientific discoveries have accumulated in a spectacular way, giving the impression that it was possible to explain the Universe without the need to resort to a god. Creator. And so it was that at the beginning of the 20th century, materialism triumphed intellectually. In a way (...) as unexpected as it is surprising, the pendulum of science has swung back in the other direction, with incredible force. The discoveries of Relativity, quantum mechanics, the expansion of the Universe, its thermal death, the Big Bang, the fine tuning of the Universe or the complexity of living things, have followed one another. This new knowledge came to dynamite the certainties anchored in the collective spirit of the 20th century, to the point that we can say today that materialism, which has never been just a belief like any other, is on the way to become an irrational belief. In a language accessible to all, the authors of this book retrace the history of these advances in a fascinating way and offer a rigorous overview of the new proofs of the existence of God. At the dawn of the 20th century, believing in a creator god seemed to oppose science. Today, wouldn't it be the opposite? An invitation to reflection and debate. (shrink)

La vie, la mort, le sexe : ces trois thèmes n'ont cessé de hanter l'homme, cet étrange animal pensant. Peu de civilisations anciennes cependant ont développé, comme l'ont fait les Grecs 500 ans avant notre ère, des réflexions et des pratiques sociales aussi voisines des nôtres encore aujourd'hui. Ils ont été plus loin que quiconque dans l'élaboration d'une pensée qui s'interroge sur la place et le rôle de l'homme au sein de l'univers. Certes, les dieux sont omniprésents. Mais ce sont (...) des humains divinisés qui ne différent guère des mortels que par leur privilège de l'immortalité. Les Grecs ont anticipé comme personne nos questionnements, nos angoisses, nos passions, nos interrogations, nos rapports avec la vie, la nature, le temps, l'amour, la mort. Nous divergeons parfois, nous convergeons souvent, mais le plus fascinant est le dialogue qui ne cesse de s'établir avec eux depuis 2500 ans.--Page 4 of cover. (shrink)

Cet ouvrage regroupe plusieurs textes centrés sur les questions cardinales de la philosophie de Merleau-Ponty, de ses premières à ses dernières oeuvres, en particulier : les questions de l'incarnation, de l'expression, de la peinture, de la vision et bien sûr du style. L'analyse est donc plutôt orientée du côté de l'esthétique et des rapports existant entre philosophie et non-philosophie. Merleau-Ponty a donné toute son importance au silence de la peinture pour tenter de comprendre la dimension du langage et de l'expression.

Le volume présente une pluralité d'approches, allant des pratiques qui produisent les sources à la généalogie de la pensée de l'action et de "la pratique". Sont aussi traitées les formes de l'enquête qui peuvent faire controverse et les réinterprétations des catégories sociales par les acteurs eux-mêmes. D'autres cas d'études portent sur les expériences de réactivation de pratiques du passé et les problèmes qu'elles posent à l'écriture historienne. Au-delà de leurs différences épistémiques, ces démarches ont en commun de proposer des chemins (...) de recherche et d'enquête qui rompent avec les versions téléologiques de l'histoire. Elles explorent des configurations qui n'enferment jamais complètement les acteurs, même lorsqu'ils opèrent dans des mondes contraignants, qu'il s'agisse d'institutions, de structures et de groupes sociaux, de concepts et de catégories cognitives. (shrink)

Il ne s'agit pas seulement ici de rendre compte de la philosophie de la technique que l'on trouve chez Platon et chez Simondon, et de quelques autres parmi les plus importantes, mais d'affronter véritablement la question : qu'est-ce que la technique? On voudrait faire apparaître d'abord le caractère exemplaire et décisif de Platon pour la compréhension de ce qu'a été la réalité technique de son temps aussi bien que pour la compréhension, aujourd'hui encore, de la réalité technique actuelle, des problèmes (...) qui sont liés à son identification comme telle et à la démarche qui convient pour son étude. C'est aller contre la tradition qui en fait un ignorant et un ennemi de la technique, préoccupé avant tout d'un monde d'Idées 'coupées' du monde sensible. Cette tradition, quasiment aussi ancienne que Platon lui-même, est toujours vivante, fondée désormais sur une représentation de la technique qui se voudrait moderne (la technique comme 'application de la science'). C'est un des intérêts de la pensée de la technique de Gilbert Simondon (prolongeant et systématisant une tradition qui passe en France notamment par Henri Bergson et Georges Canguilhem), que de délivrer de l'idée précipitée selon laquelle l'essence de la technique serait d'être une application de la science, idée dont la faiblesse est la plus évidente quand il s'agit d'une époque où la science n'existait pas encore au sens actuel. La lecture de Platon n'est pas seulement libérée par la compréhension de la technique que propose Simondon, elle est elle-même une préparation très utile à la lecture de ce dernier, reposant sur des exemples plus simples. Ce qu'apprend une philosophie de la technique, on le voit exemplairement chez Platon et chez Simondon, n'est pas seulement comment organiser des concepts et des idées (dont l'importance politique et sociale est évidente), c'est comment regarder précisément le réel, penser son existence et son évolution."--Page 4 of cover. (shrink)

The nine essays in The Appearing of God are situated on the fluid border of philosophy and theology, and follow a path leading from classic modern philosophical discussions of experience to some leading themes in contemporary phenomenology. After an introductory exploration of Kierkegaard's classic text that straddles the border between philosophy and theology, the reader is introduced to Husserl's account of perception, with its demonstration that the field of phenomena is wider than that of perceptible entities, allowing phenomena that give (...) themselves primarily to feeling. Husserl's theory of reduction is then subjected to a critique, which identifies phenomena wholly resistant to reduction. John Paul II's encyclical on Faith and Reason elicits a critical rejection of its attempt to reify the boundary between natural and supernatural, the author asserting in its place that love is the distinguishing mark of the knowledge of God. This theme is continued in a discussion of Heidegger's Being and Time, where a passing reference to Pascal invites interrogation of the work's 'methodological atheism', which is found to leave more room than appears for love of the divine. The next three chapters deal with the themes of Anticipation, Gift and Self-Identity, all exploring aspects of a single theme, the relation of present experience to the passage of time, and especially to the future. The final chapter puts that theme, together with the theme of love and knowledge, to the service of an enquiry into how theology as an intellectual enterprise relates to the practice of worship. (shrink)

Nous ne pouvons nous dispenser d'un concept linguistique du vrai. Nous ne pouvons pas davantage nous dispenser d'un concept phénoménologique du vrai. Et nous ne pouvons enfin nous dispenser de recourir à l'un et à l'autre, car le vrai se dit et le vrai se donne à l'intuition. Ces affirmations sont élémentaires. Mais les prendre au sérieux, c'est-à-dire considérer l'expérience entière de la vérité, requiert d'élargir le concept de vérité, de telle manière que : le vrai ne soit pas seulement (...) affaire de savoir mais, plus largement, affaire de connaissance ; le vrai puisse être dit dans une multiplicité de langages (philosophique, poétique, scientifique(; le vrai soit indissociable de la question de l'être-dans-le-monde ; le vrai soit à la mesure du logos, dont on montre qu'il excède la ratio sous ses formes modernes. Le vrai doit à nouveau être pensé. La pensée n'est rien de neuf. Mais son intervention dans les débats sur le vrai, au temps du nihilisme, est plus urgente que jamais. (shrink)

La 4e de couverture indique : "Qu'est-ce que le droit naturel aujourd'hui? Une approche morale du droit, qui vise à montrer les limites du droit positif, en insistant sur la nécessité d'introduire en son sein autre chose que le droit, pour le rendre plus légitime. Mais le droit naturel est aussi la valorisation, au sein du droit positif, d'un certain corpus normatif, celui des droits fondamentaux. Ce livre entend construire une troisième approche où le droit naturel ne cherche pas à (...) échapper à la juridicité, au bénéfice de la morale. Il s'agit, à partir de l'oeuvre de Michel Villey, d'élargir le propos jusqu'à la définition d'une essence du droit, opposable à certaines formes contemporaines du droit positif.". (shrink)

Ce bref texte en forme de manifeste rappelle que les mouvements de transformation sociale dirigés vers davantage de justice sont d’autant plus forts que leurs membres reconnaissent avec lucidité et compassion leurs propres implications dans les mécanismes générateurs de violences. Plutôt que des gestes de condamnation et d’annulation ( cancel ), ce sont donc des attitudes d’écoute, de soutien et de solidarité active qui sont requis.

Par-delà toute prise de position idéologique ou politicienne, la réflexion sur l'écologie est devenue de plus en plus présente dans notre société contemporaine, et les musiciens n'ont pas tardé à se sentir fortement concernés, ce qui a suscité, de leur part, des réponses de multiples natures. Certains compositeurs ont cherché à investir des lieux plus ouverts que la traditionnelle salle de concert, tandis que d'autres ont eu recours aux moyens technologiques et médiatiques les plus récents pour capter et diffuser les (...) sons qui nous entourent afin de les reprendre à leur compte ou de dialoguer avec eux, voire les révéler tels quels. La musique ayant de plus en plus tendance à envahir notre quotidien, d'autres encore ont entrepris de créer de nouveaux types d'environnement et de signalétique sonores. Et ces tentatives s'accompagnent fréquemment de confrontations avec différentes disciplines artistiques. L'initiateur d'une telle démarche n'était-il pas Erik Satie avec sa "musique d'ameublement"? Mais qu'aurait-il pensé du matraquage de la Muzak quelques décennies plus tard? (shrink)

Avec la perte d’influence de la psychothérapie institutionnelle et la montée en puissance du new management public, j’observe une remise en question de la clinique éducative au profit de démarche plus orientée vers la notion de performance. Cette évolution ne me semble pas pertinente au regard des enjeux portés par les professionnels et les publics qui demandent d’avantage semble-t-il de co-production ou de co-élaboration de la réponse sociale. Ces enjeux dépassent le clivage entre métier et profession et engagent la réflexion (...) sur le sens de l’action et fondamentalement ce que l’on nomme la clinique éducative. Les résultats mettent également en exergue une bonne collaboration entre les deux professions, les champs de tension qui apparaissent ainsi que les éléments qui l’influencent. (shrink)

L'expérience de la connaissance nous enseigne qu'il n'y a pas de Réalité Dernière, que tout train en cache un autre. Une évidence qu'il n'est pas facile d'accepter, d'où l'idée de ce train ultime, celui qui ne cacherait plus rien. La transparentisme postule l'existence, au-delà de la perception immédiate, d'un monde, d'un niveau de lecture, complètement intelligible, i.e, explicite et immédiat. D'où cette croyance en de prétendus "rayons X du savoir" qui nous dévoileraient l'envers de l'Univers.

L'expérience de la connaissance nous enseigne qu'il n'y a pas de Réalité Dernière, que tout train en cache un autre. Une évidence qu'il n'est pas facile d'accepter, d'où l'idée de ce train ultime, celui qui ne cacherait plus rien. La transparentisme postule l'existence, au-delà de la perception immédiate, d'un monde, d'un niveau de lecture, complètement intelligible, i.e, explicite et immédiat. D'où cette croyance en de prétendus "rayons X du savoir" qui nous dévoileraient l'envers de l'Univers.

Les animaux peuvent-ils avoir des droits? La souffrance animale a-t-elle une importance morale? Les animaux sont-ils dotes de conscience? Telles sont les questions abordees dans cet ouvrage, qui se propose d'approfondir quelques pistes de reflexion a travers la lecture commentee de deux textes, l'un de John Stuart Mill (extrait de L'utilitarisme), l'autre de Donald Davidson (sur la cognition animale).

Résumé Le principe de précaution est un principe pragmatique qui a trouvé une expression juridico-politique. C’est la réponse des sociétés démocratiques à de nouveaux risques. Cette intervention du principe de précaution dans la sphère démocratique explique également les controverses auxquelles il a pu donner lieu. Mais il n’est pas possible de s’en tenir aux controverses, car il y a aussi des enjeux proprement philosophiques du principe de précaution autour de trois questions majeures : le savoir, le temps et la Terre. (...) Si le principe de précaution, dans la forme constitutionnelle qu’il a prise en France, est bien la traduction, encore imparfaite et précaire, d’un principe cosmopolitique, dans le cadre d’un État particulier, on peut dire qu’il constitue un moment important dans la prise en charge politique et historique d’une responsabilité pour l’humanité. (shrink)

Although the historian confronts the question of what is not known in the same terms as does any other researcher no matter his or her discipline, the conditions of the debate are different for the historian because of the problematic nature of the science of history. While practically all the other sciences, including the social sciences, struggle against ignorance by seeking to discover and establish laws that will govern the facts, history must always face, in spite of its ever more (...) sophisticated techniques, the contingency of its materials, which are fundamentally human. The materials of history can not—in spite of what some have asserted—be contained within any single, all-encompassing mode of reasoning that would allow for the creation of constitutive abstract models. In spite of this reality the historian persists, like Sisyphus, in organizing knowledge. Man apparently has no choice but to believe that his activities have some logical basis. The historian therefore collates facts in order to develop cognitive and interpretive structures that will be durable. What gives the discipline of history its epistemological originality is the painfully central role it accords to the question, “What do we not know?” Man wants to know, believes he knows. The ignorance of historians thus seems especially upsetting when applied to our own century. How could the methodological progress of the science of history, along with the professionalization of the historian's craft, have led to an actual increase of uncertainty concerning a period so close to us in time? Today's man-in-the-street—endowed only with his memory, which seems so rich in “truths”—finds it hard to believe that any event or structure of the twentieth century could remain unknown. Limiting our inquiry to the twentieth century is not, however, justified solely by the practical consideration of trying to gain a better grasp of our times. Indeed in this brief article devoted to the relationship between ignorance and the history and historiography of the twentieth century, we will not attempt to inventory all the events, persons, mentalities or economic facts which historical knowledge has until now been incapable of explaining. Unlike the other sciences, whose struggle against ignorance is accomplished by a gradual process of nibbling at the margins of the unknown, the discipline of history must always keep in mind that the masses of granite that form the foundation of History are in fact but a body of statements that can only aspire to the status of truth. The aim of our inquiry— without of course claiming to be exhaustive—will therefore be to identify the nature of the obstacles that lie in the historian's path. These problems are of three kinds. The first concerns access to knowledge, and is tied—although not exclusively—to problems of the techniques of historical research. The second concerns the difficulties related to conceptualization and therefore to the uses of knowledge. There can be no knowing without know-how. Finally, the third pertains to the lack of permeability between history and the other human and social sciences, which creates for the historian the challenge of interdisciplinary exchange. (shrink)

At the turn of the fifteenth and sixteenth centuries, change was fast and furious: the exploration of coastal Africa by the Portuguese, the exploration of the West Indies by the Spanish, the extermination of the island Indians, the importation of black slaves to the Iberian peninsula, then the expansion of the slave trade to the American colonies - in short, the much-heralded inauguration of European colonization overseas, with all of its attendant horrors. All of this is adequately known, it seems; (...) the purpose of the present article is not to rehearse this history, even in summary. But if chronology has any value here, it is in making clear that, while the massacre of the Arawaks and the Caribbean Indians quickly attracted attention, eliciting protests that were to be renewed in the following centuries, the black slave trade and black slavery began somewhat discreetly, as if it took quite some time for the esprits libres in Europe to take notice of it. Over the three centuries leading up to the French revolution, blacks were transferred from their native countries to the American colonies. In Europe, these three centuries saw the development of Enlightenment thought, the revolt against domination by the Church, the call for human rights, and the will to democracy. The parallel is superficial, but troubling nevertheless: four facts appear to be linked together, and not merely chronologically: the massacre or de facto subjugation of the Indians, the trade and enslavement of blacks, and colonization. Is the last of these not the cause of and the key to understanding the other three - as well as a number of other phenomena? (shrink)

For many years, M. Jean d'Ormesson has been doing me the honor of asking me to write for Diogenes. More recently, he suggested that I should coordinate an issue of this review that would be devoted to my extended discipline, History, but history in the way in which I understand it. It was certainly not for lack of interest that I did not reply to the first request but, no doubt, because of the sense of a chronic lack of time (...) - almost a pleonasm - from which I, like everyone else, suffer. It was not because I was cured that I accepted the second invitation but probably because I allowed myself, with full knowledge of the facts, to entertain the idea that editing an issue would take up less time than simply contributing. … In fact, as everyone knows, the opposite is true, especially when the occasional editor also volunteers to be one of the contributors. This issue is now completed and I sincerely thank M. Jean d'Ormesson for having wished to entrust me with this task that I have enjoyed very much. (shrink)

In order to tell the story of Man and understand our emergence better, we can readily follow on from Heinz Tobien, though we do not need to go back so far in time - just a few million years.Clearly, our fundamental origin is animal. Thus it is easy to understand that in the great genealogy (known as phylogeny), there was one vital (geological) moment when our line was forever detached from the animal “kingdom.” The evidence of palaeontology, like that of (...) molecular biology, today locates this point - which is, by definition, the very point of origin of our family, the hominids - in Eastern Africa around 8 million years ago. In order to state this, palaeontology rests on two sets of results. All the most ancient hominids, without exception, are East African, and the oldest of all goes back more than 7 million years. Through the study of various characteristics of the cells of contemporary primates, having arranged them in an order of increasing complexity and having hypothesized that this contemporary complexity may be a reflection of that which developed through time, molecular biology has, on the basis of palaeontological dating, calibrated this transformation and its different stages and constructed what is called a molecular clock. In this way, it has arrived at two conclusions. The primates closest to Man are by far the great African apes (chimpanzees, gorillas), and the “distance” that separates us - in other words the degree of difference that exists between them and us - situates the divergence of our two branches at just over 7 million years. (shrink)

The rich text by Roberte Hamayon can be viewed from several angles. I will limit myself to one by noting that this particular case offers a very interesting illustration of the treatment of ethnic questions in Russia following the collapse of the USSR.

We are again going through a period of expansion in biographical literature. There is an ever greater number of publications, demonstrating the libido biographica of the reading public and also showing the interest of authors for a genre that is often treated with a great deal of care and rigor. This is not the first time in the history of letters, and each of us can find in his library a quantity of ancient, classic or modern works proving the constancy (...) of this production. However, the contemporary phenomenon takes on a different meaning. The appetite for the biographical seems to be directly linked to its value as testimony. We are living in an era of distrust with regard to rules and codes. Every individual is called on to organize his conduct and invent his existence, from which comes, it seems, this need for an example that also expresses a taste for history and a need for more truth than entertainment from the author of biographies. (shrink)