IHPST, 13 rue du Four, 75006 Paris, 2e étage. Métro Mabillon.
The talks on this page are in listed chronologically. For recent talks, scroll to the end.
24 septembre 2012, 14-16h, Tim Maudlin (New York University)
The Metaphysics of Quantum Physics
One of the major difficulties in understanding the picture of the physical world presented by quantum theory turns on more general questions of how mathematical formalisms can be used to represent the physical world. More particularly, any comprehensible understanding of a physical theory must include an account of how claims made in the language of the theory are related to the data against which the theory is tested. In the middle of the last century, many philosophers accepted a picture of how physical theories acquire empirical content which is both intrinsically problematic and historically inaccurate. I will articulate an alternative account that ties the language of the theory to the language of the data in a more straightforward way, and argue that this casts the problem of understanding quantum theory in a very different light.
27 novembre 2012, 14h-16h, Giovanni Valente (University of Pittsburgh)
Entanglement and Relativistic Causality
Relativistic causality is the requirement that causal processes cannot propagate faster than light. This requirement is incorporated in the theory of special relativity, and it is often referred to as Einstein’s causality principle. Yet, a peculiarly quantum-mechanical phenomenon known as entanglement seems to contradict such a causality condition, in that it would entail what Einstein’s referred to as a “spooky kind of action at a distance”, whereby spacelike separated physical systems may affect each other instantaneously. This tension raises the question how special relativity and quantum mechanics can peacefully co-exist, that has remained an open philosophical problem entertaining physicists and philosophers of physics for almost a century. In this talk I will Survey the status of both relativistic causality and entanglement in quantum field theory, that is our most successful theory unifying spécial relativity and quantum mechanics, and argue that the presence of entangled correlations does not entail that causal processes would propagate superluminally. In fact, even when quantum field systems are maximally entangled, relativistic causality is still satisfied.
8 janvier 2013, 10h-12h, Anjan Chakravartty (Notre Dame, http://nd.edu/~achakra1/)
Inferring Dispositions from Scientific Practice
In ongoing discussions in the metaphysics of science, several authors have claimed that the existence of irreducible causal powers or dispositions (capacities, tendencies, propensities, etc.) can be inferred from the practice of science itself. I consider the two most prominent arguments for this view, to the effect that the existence of dispositional properties can be inferred from practices of scientific explanation and practices of scientific abstraction, respectively. I contend that neither argument is successful. Dispositional realism is supported nevertheless, however, by an arguably scientistic consideration of the nature of property identity, thus affirming the importance of a dispositional ontology to the metaphysics (and epistemology) of science.
14 février 2013, de 16h à 18h, Huw Price Cambridge,http://prce.hu/w/index.html)
Representationalism – From Nihilism to Dualism
Pragmatists such as Dewey, Wittgenstein and Rorty are often anti-representationalists. (Dewey was already predicting in 1905 that pragmatism would ‘give the coup de grace to representationalism’.) I am sympathetic to that tradition, but I think that to develop it in its best form, there is a sense in which we need move in the opposite direction. Rather than abandoning the notion of representation, we need to divide it in two: hence dualism, not nihilism. In this talk I describe the motivation for this idea, and its origins in the project of combining the best elements of the different expressivist programs of Brandom on the one side, and writers such as Blackburn and Gibbard, on the other.
4 avril 2013, 14-16h, Mauro Dorato (Roma 3): Causal Explanations, structural explanations and entanglement.
By reviewing three well-known scientific revolutions (the discovery of inertia, of special and general relativity), I claim that pre-revolutionary problems that seemed to call for a causal explanation later became postulates of the new paradigm and received a structural explanation in terms of the mathematical model of the theory. I then use this historical “evidence” to vindicate (and elaborate upon) a claim advanced by Fine, according to which also quantum correlations and entanglement in general do not need to be explained causally, as they are the defining element of the new quantum order of nature.
18 avril 2013, 14h-16h, Matteo Morganti (Roma 3), Dependence and Fundamentality between Metaphysics and Science
This paper focuses on the interplay between science and metaphysics with respect to certain issues concerning the hierarchical structure of reality. In particular, it has a twofold purpose. In a first, ‘negative’ section, some arguments for so-called priority monism, recently formulated by Jonathan Schaffer, are criticised. In a more constructive second section, it is suggested that new, even more revisionary, possibilities need to be taken seriously and further explored in view of careful philosophical analysis and scientific evidence – in particular, the possibility that there is no ultimate, ontologically fundamental level.
10 Juin, 17-19,
Alan D. Sokal (Department of Physics, New York University), Does science make metaphysical assumptions?
Des notes informelles à propos du livre The Comprehensibility of the Universe, de Nicholas Maxwell
Lieu : PSL, Villa Pasteur, 62 bis rue Gay-Lussac, 75005, salle de réunion.
Does science make metaphysical assumptions? The traditional empiricist answer is “no” (subject to some qualifications to be discussed shortly): the degree of credence to be accorded to any scientific theory is — or at least ought to be — determined solely by the observational and experimental evidence. As Popper puts it, “in science, only observation and experiment may decide upon the acceptance or rejection of scientific statements, including laws and theories.” Just the facts, ma’am, as Joe Friday would say. But it is easy to see that this cannot be the whole story. Consider, for instance, that paradigmatic scientific theory, Newtonian mechanics — understood as the conjunction of the second law of motion, according to which an object’s acceleration equals the total force acting on it divided by its mass, and the law of universal gravitation, according to which each object in the universe exerts an attractive force on each other object in the universe, with a magnitude that is proportional to the product of the two objects’ masses and inversely proportional to the square of the distance separating them. (I apologize to the reader for this awkwardly verbose formulation of Newton’s laws F = ma and F = Gm1m2/r2.) And let us furthermore pretend (in order to avoid encumbering the argument with irrelevant complications) that the predictions of Newtonian mechanics are in perfect agreement with all existing observations of terrestrial and planetary motions.3 But there are numerous alternative theories that are equally well in agreement with all existing observational evidence.
25 Juin 2013, 11h-13h : Olivier Sartenaer (Université de Louvain)
« L’unité plurielle de l’émergence et les niveaux de réalité ».
November 12, 2013, 16:00: Alex Manafu (IHPST): Inter-theoretic Relations: the Brønsted-Lowry Theory of Acids and Microphysics
This paper examines the relations between the Brønsted-Lowry theory of acids and the underlying microphysical theories. It argues that these relations are complex and somewhat messy. They do not lend wholesale support to any of the philosophical theories of reduction or emergence. However, they do support particular aspects from both sides. The paper fleshes out what these aspects are, and draws some general philosophical lessons. One of these is that acidity is a sui generis chemical property, which is made possible by processes at the lower level, but which can be adequately defined only at a higher level.
December 17, 16:30, Martin Schüle (IHPST) : “The Kocher-Specker Theorem: A Case for the Emergence of Space-Time?”
In quantum physics, events can exhibit long-range correlations although there is no direct contact between them and no common cause. These so-called nonlocal correlations between space-like separated events are a central issue in quantum information science and the foundational and philosophical debate in quantum physics.
Bell’s analysis of the situation led to a no-go theorem which says that it is not possible to introduce additional variables, with certain intuitive properties, that would explain the correlations. After discussing certain conceptual difficulties with Bell’s theorem, I will discuss another no-go theorem by Kochen and Specker. I will claim that the Kocher-Specker theorem is more fundamental and will allow for a Bell-type argument involving time-like separated events instead of space-like separated ones. This might provide some evidence that the structure of space-time is an emerging phenomenon in nature.
================ 2015 =================
27 février 2015, 14-16, IHPST
Sam Fletcher (U California, Irvine),
co-organisé avec A. Grinbaum et O. Darrigol.
Title: The Topology of Intertheoretic Reduction
Abstract: Butterfield (2011) has recently presented a case for the compatibility of reduction and emergence in some of the exact sciences. He takes reduction to be given by one theory being the limit of another, and emergence to be “novel and robust behavior” arising “on the way to the limit.” Here I aim to make this idea more precise, emphasizing the necessary role of similarity relations between the models of the two theories, encoded formally by a choice of topology on them. I stress that justifying why a notion of similarity is appropriate is crucial, as it may perform much of the work in demonstrating a particular reduction’s success or failure, and in explicating the sense of “novel and robust behavior” of a candidate emergent property. To illustrate, I consider the case of gravitational theory, and the emergence of features like “objective simultaneity”.
13 mars, 14h30-17h
Carlo Rovelli (Marseille)
PART 1: The heavy (good and bad) influence of philosophy on physics.
Four historical cases illustrating the heavy influence of philosophy on physics:
– Heisenberg 1925 (radical empiricism, operationalism, anti-naive-realism)
– Einstein 1905 (Poincaré conventionalism, Schopenhauer, Mach criticisms, Berkeley)
– Feynman 1950 (Pragmatism, logical positivism)
– Post standard model particle physics 1980 (Kuhn and Popper, this is an example of BAD influence)
PART 2: Why philosophy is essential for physics and how it can be useful.
– Most scientific problems can be solved only by a change of conceptual framework. This requires something else than mere hypothetical-deductive method inside a given conceptual framework. require constant revision of the conceptual framework itself. For this, philosophers have the appropriate tools.
– Phys and Phil have different modes of investigation (empirical-quantitative-mathematical-prediction oriented, versus conceptual analysis-precision), but a *shared goal*: constructing the most effective conceptual framework for understanding the world on the basis of current knowledge.
– General framework where I feel most at ease: Quine’s naturalised epistemology.
– For this to work, what is needed is: 1. strong reciprocal knowledge, and 2. acceptance of the evolutive (historical) nature of all knowledge.
PART 3: Current conceptual problems in Phys where Phil is needed:
– General relativity: novel conceptualisation of spacetime and observability
– Quantum mechanics: Relational events and waking of realism
– Gauge theories: understanding the nature of gauge variables
– Quantum gravity: observability and realism without space and time.
I will give some basics coordinates for understating each of these.
Vincent Lam (Lausanne)
Continuity between science and philosophy of science
15 avril, 13h-16h
Laura Felline (Roma 3)
Mechanisms meet Structural explanation: a solution to the bottoming-out problem
Abstract. Many phenomena in fundamental physics, although mechanically unexplainable, are nonetheless explained by science. In particular, some of them are explained via structural explanations. The opposition between structural and mechanistic explanation is used to better qualify the non-causal and fundamental character of structural explanation. Although in a sense opposite to each other, mechanistic and structural explanations might be assimilated by a more general account of epistemic model-based explanation, providing information about the pattern of counterfactual dependences between explanans and explanandum. Finally, some arguments considered decisive in ruling out the mechanistic account as a general account of causation and causal explanation are evaluated and found inconclusive.
Iulian Toader (Bucarest)
Structural Knives and Modal Bumps
Abstract: Some structural realists include modal facts in the actual world and take its structure to be inherently modal. They also maintain that this modal structure is represented by the shared structure of the models of our scientific theories, in the sense that the shared structure encodes all physical possibilities. In my talk, I argue that these claims cannot stand together: if the representational claim is true, then modal facts cannot be included in the actual world.
Vendredi 29 mai 2014, 10h-12h:
Mathias Frisch (University of Maryland): “Causal Reasoning in Physics”.
Abstract: Many contemporary philosophers of physics (and philosophers of
science more general) follow Bertrand Russell in arguing that there is no
room for causal notions in physics. Causation, as James Woodward has put
it, has a ‘human face’, which makes causal notions sit ill with fundamental
theories of physics. In this talk I examine a range of anti-causal
arguments and show that the portrait that the neo-Russellians paint of
causation is the face of scientific representations much more generally.
Causal notions, I argue, play no less of an important role in physics than
they do in other sciences. I begin by focusing on classical physics.
If time permits, I will also discuss examples from quantum physics.