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Accueil > Archives > Séminaires des années précédentes > Séminaires 2012–2013 : archives > Philosophy and Physics 2012–2013

Axis History and Philosophy of Science of Nature

Philosophy and Physics 2012–2013

Organised by Alexandre Afriat, Alexis de Saint-Ours, Elie During, in collaboration with University Paris Ouest-Nanterre.

Presentation of the seminar

Current year. Archives : 2009-2010, 2010-2011, 2011-2012, 2013-2014.

Program 2012-2013 : Monthly sessions on Fridays, 14:00–17:00, room Malevitch-483A, building Condorcet, University Paris-Diderot, 4 rue Elsa morante, 75013 Paris – interactive campus map.

Nov. 2 2012

John Stachel (Center for Einstein Studies, Boston University)
Space-Time and Background Independence : The Hole Story.

Dec. 21

Edward Anderson and Alexis de Saint-Ours (University Paris Diderot)

Physical and Philosophical Discussion on Time and Change : Machian approaches to the Problem of Time in Quantum Gravity.

2013 Feb. 1

Julien Bernard (Ceperc, Universite de Provence)
Weyl et le problème de l’espace.

Feb. 22

Holger Lyre (University Magdeburg)
Quantum Phases and Realism about Structure.

March 29

Carlo Rovelli (Université de la Méditerranée)
Réalisme et quanta : l’objet réel n’est pas la fonction d’onde.

May 24

Fabien Besnard (EPF, Sceaux)
A friendly introduction to the concepts of noncommutative geometry.

June 28 !! 9:30–18:30
Room Luc Valentin, 454A !!


Jeremy Butterfield (Cambridge)

Reduction and Emergence in the Context of Renormalization

In previous work, I argued that reduction and emergence are compatible. I took reduction of theories a la Nagel : as deduction, usually using judiciously chosen definitions (bridge-laws). And I took emergence as behaviour or properties that are novel (by some salient standard). My idea was : reduction and emergence are often combined by one theory being deduced as a limit of another. In this talk, I will extend my previous framework to renormalization. I will argue that the explanation, using renormalization group ideas, of why non-renormalizable terms dwindle at long distances amounts to a family of Nagelian reductions. That is : a renormalization scheme that defines a flow to lower energies amounts to a set of definitions that enable deductions, from a theory describing high-energy physics, of a low-energy theory. Because the same scheme shows how many similar high-energy theories flow to correspondingly similar low-energy theories, we have a unified family of Nagelian reductions.

Nazim Bouatta (Department of Applied Mathematics and Theoretical Physics, Cambridge)

Easing into Fields and Strings : Emergence, Background Independence and all that

Theories of quantum gravity have been a recent focus of interest for philosophers of physics. Indeed, the fact that space-time geometry and diffeomorphism invariance can be said to emerge from quantum gravity has made them a natural focus, and a source for case studies, for the philosophical contrast between reduction and emergence, and related topics such as explanation. In this talk we will restrict ourselves to the so-called gauge/gravity correspondence : whose gauge theory is mercifully well-understood (at least in principle), and whose various limits and regimes have been much studied, including those on the way to the ’t Hooft limit. We will also relate this example to the wider issues, which remain topical within the philosophy of space-time, about how best, in a field theory, to define and so to understand background independence.


Gabriel Catren (CNRS)

Towards a Group-Theoretical Quantum Ontology

We shall propose a group-theoretical quantum ontology based on an analysis of the relationships between quantum mechanics and 1) the theory of constrained Hamiltonian systems (or gauge theories), and 2) Kirillov’s orbit method for constructing irreducible unitary representations of some Lie groups.

Oliver Pooley (University of Oxford)

On the alleged link between general covariance and background independence

The view that the requirement of general covariance is a constraint on a theory’s formulation, and not on its physical content, has its origins in Kretschmann’s 1917 criticisms of Einstein’s original presentation of the general theory of relativity (GR). At least in the literature on classical GR, it has since become the mainstream view. On the face of it, the view is in tension with claims made by several physicists working on quantum gravity, especially loop quantum gravity. Rovelli, for example, claims that GR’s background independence is ``expressed by’’, ``coded in’’ or ``technically realised by’’ the theory’s (active) diffeomorphism invariance. The aim of the talk is to get clear on the content and correctness of claims like Rovelli’s. I hope to show that the ``no content’’ view of general covariance is essentially correct and that the differences between GR and pre-relativistic theories are often overplayed.

Christian Wüthrich (University of California at San Diego)

Time and Space in Causal Set Theory

Causal set theory offers an elegant and philosophically rich, though admittedly inchoate, approach to quantum gravity. After presenting its basic theoretical framwork, I will show how space and time vanish from the fundamental picture it offers. The absence of space and time from the theory raises the serious question of whether such a theory can be empirically coherent at all, i.e, whether its truth would not undermine any justification we may have for believing it. If it can be shown that spacetime re-emerges from the fundamental structure in the appropriate limit, I will argue, then the threat of empirical incoherence is averted and it can be appreciated how space and time emerge from what there is, fundamentally, according to causal set theory. I shall close by sketching the prospects of the antecedent of this conditional claim.


The main ambition of the workgroup “Philosophie et Physique” (SPHERE / Université de Paris-Ouest Nanterre) is to combine certain aptitudes in history and philosophy of physics in an attempt to engage issues that may resonate with transversal philosophical research concerning, in particular, the nature of space and time. It seems to us that the twentieth-century transformations of the concept of space-time—which may even be abandoned once quantum theory and general relativity are unified—are fertile ground for such an enterprise. The search for quantum gravity poses technical and conceptual problems ; many physicists feel that such a theory is best developed by re-thinking the foundations of quantum mechanics and general relativity. It is in this spirit that we propose our research seminar, whose purpose is to examine the evolution of the concepts of space and time, from the introduction of Raumzeit by Minkowski in 1907-8 to modern theories (strings, loops, causal sets, non-commutative geometries) which—despite differences—seem to agree, in ways that will have to be clarified, on the disappearance of space-time.

What is a quantum space-time ? What are the consequences of a ‘background independent’ quantum theory of gravitation for space, time, localisation and evolution ? How does classical space-time emerge from discrete structures ? These are some of the questions that will be raised in the seminar.

But one should also wonder how philosophy of physics responds to certain ‘purely philosophical’ questions concerning ontology, metaphysics, and more generally the philosophy of nature or of mind. Indeed the remarkable recent publications in history and philosophy of physics have barely got beyond the narrow circle of philosophers and historians of science, even when they re-awaken issues belonging to the whole history of philosophy (debates on the status of objects, of properties, on relationism and substantivalism, on the meaning of time or becoming or even the problem of individuation). So it seems best to remain open, and include in the workgroup not only well-known specialists in history and philosophy of physics, but also scientists (mathematicians, physicists) interested in the conceptual issues of their disciplines, and philosophers wanting to stay in touch with intuitions and ideas that somehow emerge from contemporary physics. It is in this sense that the “et” of “Philosophie et Physique” expresses the idea of a new mode of cooperation and interaction between areas and disciplines, while maintaining a privileged relationship with ideas specifically related to the development of physical rationality.

Élie During

(University Paris Ouest-Nanterre and CIEPFC-ENS)

Alexis de Saint-Ours

(REHSEIS-SPHERE / University Paris Diderot)

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