9-10 mai 2016 : Workshop international sur l'"émergence dans les sciences de la matière"

Ce workshop est organisé dans le contexte du séminaire de maitrise LFILO2930 et du séminaire doctoral LISP3200. Outre des présentations de leurs travaux réalisées par les étudiants, le workshop sera l'occasion de la rencontre d'experts internationaux.

Le workshop sera bilingue Français-Anglais.

Programme des journées

9 mai

10h-11h30 – Paul Humphreys : "Transformational emergence"
11h45-12h15 – Présentation étudiante : Gwenaël Laurent
12h15-14h – Pause midi
14h-15h30 – Alexandre Guay & Olivier Sartenaer : "Emergent quasiparticles. Or how to get a rich physics from a sober metaphysics"
15h30-16h – Présentation étudiante : Astrid Modera
16h15-17h45 – Elena Castellani & Sebastian de Haro Ollé : "Duality and emergence"

10 mai

9h-10h30 – Dominique Lambert : "Modelling emergence: some epistemological questions"
10h45-12h15 – Vincent Ardourel : "Emergence and infinite idealizations in statistical mechanics"
12h15-14h – Pause midi
14h-15h30 – Matteo Mossio : "What does it mean to be an antireductionist in contemporary biology?"
15h30-16h – Présentation étudiante : Philippe Van Cutsem
16h15-17h45 – Johannes Maertens : "The emergence of biological individuality: a Darwinian perspective"

Abstracts

Paul Humphreys (Université de Virginie)
« Transformational Emergence »

This paper argues for a particular type of diachronic emergence. I shall begin by arguing that many of the problems associated with emergence result from an unnecessary commitment to synchronic accounts of emergence, a commitment which began with C.D. Broad and retains its grip on contemporary approaches. I shall then describe an alternative tradition, explain what a diachronically fundamental entity is, and provide an account based on the diachronic emergence of new types of entity. Two examples will be given, one an accessible example from sociology that is hypothetical and a more plausible candidate that appeals to muon decay in the Standard Model. I shall conclude with some brief remarks about the distinctions between invariance of law forms, of fundamental constants, and of types of fundamental particles and how the account of emergence given here relates to recent work on emergence by Alexandre Guay and Olivier Sartenaer.

Alexandre Guay & Olivier Sartenaer (Université catholique de Louvain)
« Emergent Quasiparticles. Or How to Get a Rich Physics from a Sober Metaphysics »

Robert B. Laughlin, one of the co-winners of the 1998 Nobel prize in physics, awarded for his significant contribution to our understanding of the fractional quantum Hall effect, has recently been one of the main physicists who championed a view of emergence that can reasonably be considered as ontological. Among the different facets of Laughlin’s emergentism is the claim that anyons – the quasiparticles involved in the fractional quantum Hall effect – have a special ontological status, namely, they are to be considered among the fundamental building blocks of reality, and this in spite of their existential dependence on a very specific experimental context. In our talk, we propose to (i) unpack the main tenets of Laughlin’s emergentism and, more precisely, his claims about the putative emergence of anyons, (ii) evaluate the relevance of one of the rare philosophical reconstruction of Laughlin’s emergentism, namely the “mutualist dynamics” put forward by Carl Gillett in his forthcoming book –, (iii) propose an alternative, metaphysically cheaper strategy of making sense of Laughlin’s insights – a strategy embedded in the recent “transformational” framework advocated by Paul Humphreys –, and finally (iv) formulate some remarks about the status of quantum individuals in the light of the particle/quasiparticle distinction.

Elena Castellani (Université de Florence) & Sebastian de Haro Ollé (Université d’Amsterdam)
« Duality and Emergence »

Duality and emergence are two notions in an intriguing relation: on the one side, they seem to be closely connected, on the other side, they are clearly distinct—perhaps even mutually exclusive? The key feature, in the case of duality, is the kind of equivalence between two theories that it entails (or two descriptions of the same theory, in case of self-duality). In the case of emergence, the focus is rather on the aspect of novelty that the notion entails, and thus, apparently, on a lack of equivalence between two theories or phenomena. The dualities which are of great relevance in field and string theory, however, seem to be related to emergence: in many cases, the dual correspondence seems to give a form of emergence (new particles or new phenomena). How to combine these apparently contrasting features?
In this talk we will explore in which sense analysing the contrast between duality and emergence can be helpful in clarifying their meaning. The key point of contrast with respect to which comparing the two notions will be the following: whereas duality always entails theoretical (formal, or representational) equivalence, emergence, by contrast, assumes a representational asymmetry. We will discuss a number of mechanisms which lead to such asymmetry and spell out whether, and how, duality and emergence can coexist. In particular, we will consider two duality cases, which are of great relevance in today’s theoretical physics: namely, the case of weak-strong duality or S-duality (which can be seen as a generalization of electric-magnetic duality) in quantum field theory and string theory, and the case of gauge/gravity dualities in string theory.
For what regards weak-strong duality, the focus will be on the meaning of the dual correspondence between ‘elementary’ and ‘composite’ particles that this kind of duality apparently implies. At first sight, the correspondence could be interpreted as giving rise to new objects or a new way of looking at the same objects. The question is then how to intend this novelty feature given the representational symmetry of a duality equivalence.
The dualities considered in our second example concern the relation of equivalence that can be established between gravity and gauge theories. More precisely, these dualities suggest that the dynamics of spacetime and the flow of parameters in quantum field theory (QFT) are intimately related. The direction along which the QFT’s couplings ‘flow’, typically an energy scale, is reinterpreted as a dimension (spatial or temporal) in which fields can evolve. It is often claimed that space, time, and-or gravity ‘emerge’ from a lower-dimensional theory in this way. In the second part of the talk we will: (i) present a framework for discussing emergence in cases in which two theories are related by duality; (ii) assess the claims of emergence in gauge/gravity dualities; (iii) analyse the possibility that diffeomorphism invariance is itself emergent.

Dominique Lambert (Université de Namur)
« Modelling emergence: some epistemological questions »

Starting from some mathematical descriptions of what we can call emergent structures or properties, we will try to address some questions concerning their epistemological status.

Vincent Ardourel (Université catholique de Louvain)
« Emergence and Infinite Idealizations in Statistical Mechanics »

It is often argued that physical phenomena studied by statistical mechanics like phase transitions are emergent since they require infinite idealizations to be explained (e.g Batterman 2005). In this talk, I shall argue against this mandatory use of infinite idealizations in statistical mechanics. In particular, I shall investigate new theoretical approches that explain phase transitions without using infinite idealizations. I shall also discuss the case of another alleged emergent phenomenon in statistical mechanics that is the appearance of irreversibility within the kinetic theory of gas (Jones 2006).

Matteo Mossio (Université Paris 1 Panthéon-Sorbonne)
« What does it mean to be an antireductionist in contemporary biology? »

Over the past few decades, the philosophical debate about reductionism in biology has mainly focused on molecular biology, and on the question whether biological phenomena could be explained by appealing to the molecular mechanisms underling them. In this respect, contemporary biology seems to lean toward an antireductionist perspective. In this talk, I will argue that two distinct kinds of explanatory reductionism should be distinguished when describing this debate: genetic reductionism, according to which biological phenomena are determined by the genetic system and the mechanisms through which genetic information is expressed; and molecular reductionism, according to which
biological phenomena are determined by the mechanisms taking place at the molecular level. An antireductionist stance can therefore take two different forms: holism, when opposed to genetic reductionism, and emergentism, when opposed to molecular reductionism. I will suggest that the current antireductionist trend in biology is better understood as a trend toward a more holistic rather than emergentist perspective. This holds also for organicist accounts, in spite of the fact that they are sometimes described as involving strong interpretations of emergence. I will conclude with two clarifications. First, emergentism might nevertheless be justified in biology, but more compelling arguments (and examples) should be provided. Second, although contemporary antireductionism does not primarily affect molecular explanatory reductionism, it does not follow that biological explanations should be reduced to molecular ones here and now. I will advocate a methodological antireductionism according to which biology needs autonomous theories at different levels of description. No reduction now, but unification when possible or suitable.

Johannes Martens (Université Paris 1 Panthéon-Sorbonne)
« The emergence of biological individuality: a Darwinian perspective »

In the living world, individuality is often regarded as a distinctive, physiological property of multicellular organisms (plants and animals)—and, more generally, of biological entities whose parts are functionally integrated and directed toward the survival and the reproduction of the whole. Since the 1980’s, however, this property has been the increasing focus of evolutionary theorists, who proposed a theoretical framework, based on multilevel selection theory, to understand its emergence during the history of life. As a result, the existence of biological individuals is now commonly envisaged as a contingent product of the Darwinian process—a process during which entities (e.g. unicellular organisms) at a lower level became aggregated into a larger emerging unit (e.g. a multicellular organism), thus generating a new level of biological organization. In this presentation, I will expose the main conceptual/theoretical features of this approach, and show how it can shed light on our intuitive representation of biological individuality as an emergent property.