What are individuals? How can they be identified? These are crucial questions for philosophers and scientists alike. Criteria of individuality seem to differ markedly between metaphysics and the empirical sciences - and this might well explain why no work has hitherto attempted to relate the contributions of metaphysics, physics and biology on this question. This timely volume brings together various strands of research into 'individuality', examining how different sciences handle the issue, and reflecting on how this scientific work relates to (...) metaphysical concerns. The collection makes a major contribution to clarifying and overcoming obstacles to the construction of a general conception of the individual adequate for both physics and biology, and perhaps even beyond. (shrink)

Several advocates of the lively field of “metaphysics of science” have recently argued that a naturalistic metaphysics should be based solely on current science, and that it should replace more traditional, intuition-based, forms of metaphysics. The aim of the present paper is to assess that claim by examining the relations between metaphysics of science and general metaphysics. We show that the current metaphysical battlefield is richer and more complex than a simple dichotomy between “metaphysics of science” and “traditional metaphysics”, and (...) that it should instead be understood as a three dimensional “box”, with one axis distinguishing “descriptive metaphysics” from “revisionary metaphysics”, a second axis distinguishing a priori from a posteriori metaphysics, and a third axis distinguishing “commonsense metaphysics”, “traditional metaphysics” and “metaphysics of science”. We use this three-dimensional figure to shed light on the project of current metaphysics of science, and to demonstrate that, in many instances, the target of that project is not defined with enough precision and clarity. (shrink)

In this paper, we put forward a new account of emergence called “transformational emergence”. Such an account captures a variety of emergence that can be considered as being diachronic and weakly ontological. The fact that transformational emergence actually constitutes a genuine form of emergence is motivated. Besides, the account is free of traditional problems surrounding more usual, synchronic versions of emergence, and it can find a strong empirical support in a specific physical phenomenon, the fractional quantum Hall effect, which has (...) long been touted as a paradigmatic case of emergence. (shrink)

The concept of genidentity has been proposed as a way to better understand identity through time, especially in physics and biology. The genidentity view is utterly anti-substantialist in so far as it suggests that the identity of X through time does not presuppose whatsoever the existence of a permanent “core” or “substrate” of X. Yet applications of this concept to real science have been scarce and unsatisfying. In this paper, our aim is to show that a well-defined concept of functional (...) genidentity can be crucial to shed light on identity through time in classical physics and especially in biology. Finally, we show that understanding identity on the basis of continuity suggests a move towards an ontology of processes. (shrink)

In this paper, we show that it is not a conceptual truth about laws of nature that they are immutable (though we are happy to leave it as an open empirical question whether they do actually change once in a while). In order to do so, we survey three popular accounts of lawhood—(Armstrong-style) necessitarianism, (Bird-style) dispositionalism and (Lewis-style) ‘best system analysis’—and expose the extent, as well as the philosophical cost, of the amendments that should be enforced in order to leave (...) room for the possibility of changing laws. (shrink)

Among the very architects of the recent re-emergence of emergentism in the physical sciences, Robert B. Laughlin certainly occupies a prominent place. Through a series of works beginning as early as his Nobel lecture in 1998, a lecture given after having been awarded, together with Störmer and Tsui, the Nobel prize in physics for its contribution in the elucidation of the fractional quantum Hall effect, Laughlin openly and relentlessly advocated a strongly anti-reductionistic view of physics – and, more particularly, of (...) the interface between condensed matter and particles physics – which culminated in what can be considered his emergentist manifesto: A Different Universe. Reinventing Physics from the Bottom Down (2005). In spite of this prominent role in the vindication of emergentism, rare are the philosophers, among whom even those sympathetic to the idea of emergence, who have paid serious attention to Laughlin’s insights. The subtleties of his view – it is true, often concealed in many technicalities – have accordingly, and somewhat unfortunately, mainly passed unnoticed. (shrink)

The elucidation of the gauge principle ‘‘is the most pressing problem in current philosophy of physics’’ said Michael Redhead in 2003. This paper argues for two points that contribute to this elucidation in the context of Yang–Mills theories. (1) Yang–Mills theories, including quantum electrodynamics, form a class. They should be interpreted together. To focus on electrodynamics is potentially misleading. (2) The essential role of gauge and BRST symmetries is to provide a local field theory that can be quantized and would (...) be equivalent to the quantization of the non-local reduced theory. If this is correct, the gauge symmetry is significant, not so much because it implies ontological consequences, but because it allows us to quantize theories that we would not be able to quantize otherwise. Thus, in the context of Yang–Mills theories, it is essentially a pragmatic principle. This does not seem to be the case for the gauge symmetry in general relativity. (shrink)

The transference theory reduces causation to the transmission of physical conserved quantities, like energy or momenta. Although this theory aims at applying to all felds of physics, we claim that it fails to account for a quantum electrodynamic effect, viz. the Aharonov-Bohm effect. After having argued that the Aharonov-Bohm effect is a genuine counter-example for the transference theory, we offer a new physicalist approach of causation, ontic and modal, in which this effect is embedded.

This chapter introduces the main issues and themes of the volume. Approaches to individuality from metaphysics and philosophy of science are contrasted. Recent philosophical developments regarding concepts of biological and physical individuality are exposed. These research trends show how philosophy of physics and philosophy of biology address differently the question of what an individual is. Five main divergences are identified: the centrality of part-whole questions, the issue of identical individuals, the importance of the Principle of the Identity of Indiscernibles and, (...) finally, the importance of structuralist concerns. At the end of the chapter, the structure of the book is explained in detail. (shrink)

This article explores the relation between the concept of symmetry and its formalisms. The standard view among philosophers and physicists is that symmetry is completely formalized by mathematical groups. For some mathematicians however, the groupoid is a competing and more general formalism. An analysis of symmetry that justifies this extension has not been adequately spelled out. After a brief explication of how groups, equivalence, and symmetries classes are related, we show that, while it’s true in some instances that groups are (...) too restrictive, there are other instances for which the standard extension to groupoids is too un restrictive. The connection between groups and equivalence classes, when generalized to groupoids, suggests a middle ground between the two. *Received July 2007. †To contact the authors, please write to: Alexandre Guay, UFR Sciences et Techniques, Université de Bourgogne, 9 Avenue Alain Savary, 21078 Dijon Cedex, France; e‐mail: [email protected] ; or to Brian Hepburn, Department of Philosophy, University of British Columbia, 1866 Main Mall E370, Vancouver, BC, Canada V6T 1Z1; e‐mail: [email protected]. (shrink)

The object of this paper is to look at the extent and nature of the uses of analogy during the ªrst century following the so-called scientiªc revolution. Using the research tool provided by JSTOR we systematically analyze the uses of “analog” and its cognates (analogies, analogous, etc.) in the Philosophical Transactions of the Royal Society of London for the period 1665–1780. In addition to giving the possibility of evaluating quantitatively the proportion of papers explicitly using analogies, this approach makes it (...) possible to go beyond the maybe idiosyncratic cases of Descartes, Kepler, Galileo, and other much studied giants of the so-called Scientiªc Revolution. As a result a classiªcation of types of uses is proposed. Relations between types of analogies and research ªelds are also established. In this paper we are less interested in discussing the “real nature” or “essence” or even the cognitive limitations of analogical thinking than in describing its various uses and different meanings as they changed over the course of a century. (shrink)

Essay review of Gauging What’s Real: The Conceptual Foundations of Contemporary Gauge Theories R. Healey. Oxford University Press (2007). To be published in the Studies in History and Philosophy of Modern Physics, 39(3):687-693, 2008.

Dans Science, Perception and Reality, Sellars distingue l’image manifeste de l’homme et l’image scientifique de l’homme. La première est obtenue à partir de la façon dont nous prenons conscience de nous-mêmes comme humains dans le monde. La seconde correspond à ce que les différentes sciences nous amènent à postuler sur la manière dont l’homme est constitué. Van Fraassen, lui, étend au monde ces concepts...

Dans cet essai, je compte me concentrer sur certains aspects épistémologiques de l’expertise car le risque engendre de nouveaux et difficiles défis dans ce domaine. Ma question sera d’identifier et de circonscrire des facteurs qui diminuent la confiance qu’un agent cognitif pourrait avoir envers un expert et ce, en contexte de risque. Ceci n’exclut bien sûr pas que d’autres aspects (par exemple sociaux et politiques) soient importants et je renvoie le lecteur à la vaste littérature sur le sujet. De manière (...) concrète, je mettrai en évidence comment la question du risque accentue le problème du rôle des valeurs contextuelles en épistémologie. Pour ce faire, dans la première section, je compte brièvement expliquer comment l’expertise scientifique implique une forme aigüe du problème de la connaissance par témoignage. Dans la deuxième section, j’exposerai comment la notion de risque introduit le problème des valeurs non-épistémiques en science et ce, de deux façons : par l’évaluation et la valorisation. La troisième section sera consacrée à exposer quelques approches pour sauvegarder l’intégrité et la crédibilité de l’expertise scientifique en contexte de risque. (shrink)

Il y a cent ans paraissaient un ouvrage de logique qui a marqué considérablement les études dans ce domaine tout au long du XXe siècle, soit que l’on en poursuivit le projet, soit, au contraire, que l’on en critiqua la démarche. Les Principia Mathematica de Russell et Whitehead sont donc une œuvre majeure sur laquelle il n’était par inutile de revenir en ce début du XXIe siècle. Certes la question à laquelle ils étaient censés répondre, c'est-à-dire celle d’un fondement rigoureux (...) et solide des mathématiques sur la logique formelle paraît aujourd’hui dépassée. Les travaux de Gödel dans les années trente du siècle précédent ont d’une certaine façon mis fin aux ambitions du formalisme et du logicisme tels qu’ils s’exprimaient dans cet ouvrage. Cependant, de nombreuses autres questions ont été soulevées par ce texte que l’ouvrage ici présenté tente d’élucider. Les articles qui le composent reprennent, entre autres, le débat qui opposa à la démarche de Russell aussi bien l’intuitionnisme que les travaux de Lesniewski. Le travail présenté ici montre combien demeure aujourd’hui vivante la philosophie de la logique en langue française, ce dont on peut se réjouir. (shrink)

This paper is an analysis of the geometrical interpretation of local gauge symmetry for theories of the Yang-Mills type.

This paper shows how the study of surpluses of structure is an interesting philosophical task. In particular I explore how local gauge symmetry in quantized Yang-Mills theories is the by-product of the specific dynamical structure of interaction. It is shown how in non relativistic quantum mechanics gauge symmetry corresponds to the freedom to locally define global features of gauge potentials. Also discussed is how in quantum field theory local gauge symmetry is replaced by BRST symmetry. This last symmetry is apparently (...) the result of the fact that we do not know how to define quantum Yang-Mills theories without unphysical gauge boson states. Since Yang-Mills theories describe successfully three of the four fundamental interactions the elucidation of this symmetry is a pressing philosophical question. (shrink)

The elucidation of the gauge principle ``is the most pressing problem in current philosophy of physics" Redhead. This paper argues two points that contribute to this elucidation in the context of Yang-Mills theories. 1) Yang-Mills theories, including quantum electrodynamics, form a class. They should be interpreted together. To focus on electrodynamics is a mistake. 2) The essential role of gauge and BRST surplus is to provide a local theory that can be quantized and would be equivalent to the quantization of (...) the non-local reduced theory. (shrink)

This document (in French) is an introduction to the philosophy of physics that I wrote for Anouk Barberousse (ed.), Manuel des Issambres, Gallimard, to be published.

This chapter (in French) compares the ways to access to events in science and in art. In particular, the Déotte's concept of "appareil" is discussed. To be published in Jean-Louis Déotte and Sylvestra Mariniello (ed.), Appareil et Intermédialité, L'Harmattan, 2007.

Compte rendu de L. Boi, Symétries, brisures de symétries et complexité en mathématiques, physique et biologie, Peter Lang.

Le risque comme l’expertise sont des sujets d’une rare richesse, comme le confirme la vaste littérature sur ces questions. Lorsqu’ils sont croisés, les difficultés que chacun d’entre eux soulève s’en trouvent renforcées. Le présent ouvrage est le produit des sixièmes conférences Pierre Duhem qui avaient pour thème : risque et expertise. Il rassemble les textes originaux de l’économiste Marc Fleurbaey et du philosophe Sven Ove Hansson, ainsi que les échanges qu’ils ont eu avec les commentateurs Mikaël Cozic, Minh Ha-Duong et (...) Emmanuel Henry. Un essai introductif, d’Alexandre Guay, complète le tout. (shrink)

La transformation du mode de production des connaissances scientifiques va de pair avec une évolution significative des attentes de la société vis-à-vis des sciences, et soulève pour le philosophe de nouvelles questions : qu’est-ce qui est vraiment nouveau dans le régime actuel de production des connaissances ? Quel rôle et quelle responsabilité pour le chercheur face à la demande croissante d’expertise scientifique ? Quelle attitude avoir face à des avancées technologiques touchant à la nature même de l’Homme ? Le citoyen (...) doit-il être davantage impliqué dans le choix des grandes priorités de la recherche ? Cet ouvrage offre une sélection variée et accessible de travaux actuels en philosophie des sciences explorant les facettes multiples des relations entre science et société. (shrink)

This thesis is a philosophical analysis, and in particular an ontological one, of symmetries in modern physics. In the first two chapters, the thesis analyzes the foundation of the concept of symmetry, which is defined as an invariance under a possible change to the system being studied. In the rest of the thesis, various philosophical problems concerning particular symmetries are discussed. This begins in the third chapter with an analysis of the formalization of the definition of symmetry given above in (...) terms of groups and groupoids, highlighting their advantages and limitations. The fourth chapter gives a geography of the uses of symmetry in physics. To achieve this, different criteria for the classification of symmetries in physics are discussed. The thesis concludes with a detailed examination of the ontological status of local gauge symmetry in classical and quantum physics. In this chapter, it is argued that gauge symmetry is the result of a surplus of structure. This result is surprising because gauge symmetry is generally considered the most fundamental symmetry, and is in fact one of the cornerstones of virtually all theoretical attempts to describe the fundamental interactions. (shrink)