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)

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)

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.

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)

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...

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: alexandre.guay@gmail.com ; or to Brian Hepburn, Department of Philosophy, University of British Columbia, 1866 Main Mall E370, Vancouver, BC, Canada V6T 1Z1; e‐mail: brh15@interchange.ubc.ca. (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 paper is an analysis of the geometrical interpretation of local gauge symmetry for theories of the Yang-Mills type.

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 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)

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.

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)