On the Intrinsically Ambiguous Nature of Space-Time Diagrams

When the German mathematician Hermann Minkowski first introduced the space-time diagrams that came to be associated with his name, the idea of picturing motion by geometric means, holding time as a fourth dimension of space, was hardly new. But the pictorial device invented by Minkowski was tailor-made for a peculiar variety of space-time: the one imposed by the kinematics of Einstein’s special theory of relativity, with its unified, non-Euclidean underlying geometric structure. By plo tting two or more reference frames in relative motion on the same picture, Minkowski managed to exhibit the geometric basis of such relativistic phenomena as time dilation, length contraction or the dislocation of simultaneity. These disconcerting effects were shown to result from arbitrary projections within four-dimensional space-time. In that respect, Minkowski diagrams are fundamentally different from ordinary space-time graphs. The best way to understand their specificity is to realize how productively ambiguous they are

Pierre-Henri Castel, les vies de l'esprit, dossier de la revue Critique

Numéro thématiquePenser les métamorphoses de l’« esprit malade » du point de vue d’une philosophie nourrie par l’ensemble des savoirs des sciences humaines – psychiatrie, psychanalyse, sociologie, anthropologie, histoire –, mais aussi par les sciences cognitives, le droit ou la littérature, tel est l’impressionnant projet mené depuis une quinzaine d’années par Pierre-Henri Castel. Ses deux derniers ouvrages consacrés au problème de l’obsession et de l’autocontrainte racontent les histoires secrètes ou parallèles du sujet contemporain, normé par l’idéal de l’autonomie mais sommé en même temps, et de mille façons, d’être vraiment lui-même, c’est-à-dire un individu. Un dialogue précis s’engage sur ce point avec Freud et Lacan, mais aussi avec Mauss, Elias ou Foucault, dans un souci constant de revenir au concret, de respecter l’« épaisseur » des descriptions de cas. Un long entretien avec l’auteur nous donne un aperçu de sa méthode, tandis que les lectures croisées de Bruno Karsenti et de Paul Dumouchel nous font entrer dans les coulisses du grand œuvre

De la relativité à l espace-temps (Bergson entre Einstein et Poincaré)

Durée et Simultanéité, l ouvrage que Henri Bergson consacre en 1922 à la théorie de la relativité, constitue le point de départ de cette étude. Celle-ci entend dégager la configuration conceptuelle dans laquelle intervient le philosophe, au croisement de la physique et de la métaphysique, dans une confrontation souvent implicite avec les différentes versions possibles de la relativité : celle d Einstein, mais aussi celle de Lorentz et de Poincaré. Il s agit donc d éclairer un contexte historique en en extrayant une sorte d épure qui permette de faire se rencontrer Einstein, Poincaré et Bergson sur des problèmes communs. La thèse suit deux fils conducteurs. D une part, le concept d éther, pris dans sa signification physique, mais également philosophique (celle d une connexion universelle des phénomènes). D autre part, un couple de principes que chaque protagoniste articule et interprète à sa manière : le principe de localité (1ère partie) et le principe de relativité (2e partie). Sur cette base, il apparaît que les arguments de Bergson concernant l universalité du temps réel croisent des motifs qui doivent autant à Poincaré qu à Einstein. Une partie des malentendus liés à la réception de Durée et Simultanéité s en trouve éclairée (3e partie).Henri Bergson s 1922 essay on relativity theory, Durée et Simultanéité (Duration and Simultaneity), is the origin of this study. The conceptual framework in which Bergson operates belongs to physical theory as well as metaphysics ; it involves an often implicit confrontation with conflicting versions of relativity : that of Einstein, but also that of Lorentz and Poincaré. The aim of this study is to shed light on this historical context, while extracting a working model in which Bergson, Einstein and Poincaré can be shown to address common issues. The thesis follows two main threads. The first thread is the aether concept considered in its physical implications as well as in its broader metaphysical scope (as the connecting principle of all phenomena). The second thread is the conjunction of the principle of locality (part I) with the principle of relativity (part II), which each of the protagonists interprets in its own way according to a specific montage. Bergson s arguments concerning the universality of real time (or duration) are often better understood with reference to Poincaré. This explains part of the misgivings surrounding the reception of Durée et Simultanéité (part III).NANTERRE-BU PARIS10 (920502102) / SudocSudocFranceF

we bergsonians: the kyoto manifesto

International audienceOf the philosophers working today, who deserves to be regarded as a true Bergsonian? Conferences and seminars devoted to “Bergson studies” may not be the best testing ground. When Aristotle paid tribute to his master in the famous section of the Metaphysics on the doctrine of forms (“We, Platonists...”), it was to develop his ideas in new directions. The result, as we all know, was a different philosophical system entirely. It would be astonishing if re-thinking the doctrines of durée, becoming and genuine novelty were not similarly capable of yielding new insights and pointing to new directions beyond Bergson’s work: not merely a return to Bergson, a neo-bergsonism, but a philosophy for our own times. A philosophy, however, cannot be instituted by decree; it needs to be actually created. Now it may well be possible to be a Bergsonian despite Bergson, and—at least up to a point—against Bergson, but if the distinguishing trait of bergsonism is its methodology, we first need to ensure that this methodology continues to be of genuine use. We need to explore what this methodology can deliver today, with regard to the problems that we are currently confronted with. In this regard it is obvious that Bergson scholars aren’t themselves always very Bergsonian when it comes to the concrete forms of philosophical inquiry. As Gilson aptly put it: “The true Bergsonians are not those who merely repeat Bergson’s conclusions. Rather, they are those who—following his example—make these conclusions their own, and in different areas succeed in doing something analogous to what Bergson did.”1 We, Bergsonians, have read and re-read Bergson; we have studied the complex ways in which his philosophy has been received. We have defended him against his detractors; we have corrected misunderstandings, provided the overlooked context of his oeuvre, and felt the singularity and force of his theses, the subtlety of his way of thinking: demanding and “difficult,” as Bergson himself acknowledged, misleading in its apparent informality (“How on Earth did anyone miss that?”, he wonders). All this was necessary. But now is not the time to give a second youth to Bergson’s “philosophie nouvelle.” Bergson is already amongst us, and he is not lacking in friends. The question we find ourselves confronted by is how best to harness the impetus of his philosophy, even if this involves directing it along new lines. Bergsonism has been interpreted in various ways: the point is to change it and put it to work in the context which is manifestly very different from Bergson’s own. We are setting out the case for an expanded bergsonism

Contrainte intérieure et fragilité de l'agir

Entretien réalisé en décembre 2013-janvier 2014 par Élie During et Laurent Jeanpierr

La science-fiction, un laboratoire philosophique

Macadam philo, émission de France Culture animée par François NoudelmannSe déplacer vers des objets négligés de la philosophie permet non seulement de découvrir des régimes de pensée inventifs mais aussi de revenir aux textes philosophiques pour en révéler la part de fiction. Les films, les romans, les installations artistiques relevant de la SF sont autant d'exercices philosophiques qui interrogent l'identité humaine, ses métamorphoses, sa disponibilité à composer de nouveaux êtres en s'hybridant avec les machines. Les cybercorps et les mutants ont remplacé les robots dans l'imaginaire de la science-fiction. Font-ils surgir des questions inédites, issues des progrès biotechnologiques, ou présentent-ils de nouvelles figures pour d'anciens problèmes philosophiques

Who am I?: beyond “I think, therefore I am”

Can we ever truly answer the question, “Who am I?” Moderated by Alex Voorhoeve (London School of Economics), neuro-philosopher Elie During (University of Paris, Ouest Nanterre), cognitive scientist David Jopling (York University, Canada), social psychologist Timothy Wilson (University of Virginia), and ethicist Frances Kamm (Harvard University) examine the difficulty of achieving genuine self-knowledge and how the pursuit of self-knowledge plays a role in shaping the self