For anyone in the Fediverse who might be interested in #philosophy of #physics, I’m excited to share this #workshop I’ve been organising with some friends, on metaphysical and epistemological problems in #quantummechanics. Some very cool speakers will join us for interesting discussions, on the 28th of June at #usi in #lugano
https://www.usi.ch/en/feeds/31385

www.usi.chRatio Workshop: Metaphysical and Epistemological Perspectives on Quantum TheoryDate and time: Saturday, June 28th. From 9:30am to 5pm. The Workshop “Metaphysical and Epistemological Perspectives on Quantum Theory” will focus on philosophical questions arising within fundamental physical theories, especially quantum mechanics. The workshop will host international speakers, fostering discussion with the local research community on key issues in the foundations of physics. Location: Room A-23, Red Building. Tim Maudlin (New York University) Title: Ontology and Epistemology in Quantum Context Abstract: A physical theory only acquires empirical content if its claims can be directly tested against observational data. But, as John Bell emphasized in “The Theory of Local Beables”, observational data is always (and seemingly must always be) reported in terms of what he called “local beables”: the shape, constitution, and motion of localized macroscopic objects in space-time. Therefore, the only obvious way for a physical theory to acquire empirical content is to postulate that there are such localized macroscopic objects. And the only way we have ever been able to account for localized macroscopic objects in physics is by postulating that they are composed of localized microscopic objects. But “plain vanilla” quantum theory, as presented in textbooks, not only does not postulate just things, it largely seems to positively deny there are such things. That leads at least an epistemic puzzle, if not an epistemic catastrophe. I will consider some of the ways out of the catastrophe. Valia Allori (University of Bergamo) Title: Why is there no consensus on the foundations of quantum mechanics? Abstract: Quantum mechanics is regarded by many as problematic for the scientific realist (among other things) because it looks like the prototypical example of underdetermination of theory by data: there are so many quantum theories which are (effectively) empirically equivalent, so how could the realist choose which one to believe? In this paper, I argue that the disagreement about theory choice in the quantum domain can be tracked down to specific features a fundamental physical theory should have in order to be satisfactory. People disagree about these desiderata because they disagree about which explanatory schema one should look for in a theory. This is, I argue, what leads different people to favor different theories. First, I show that the proponents of the information-theoretic approach, since they focus on empirical adequacy, are naturally led to look for an explanation in terms of principles, which is provided by standard quantum theory. In contrast, primitive ontologists favor a constructive understanding, which requires a spatiotemporal microscopic fundamental ontology, which guides them towards favoring the pilot-wave theory. Instead, Everettian approaches, which center around physical practice, conceive of quantum theory as a framework, and this makes them prefer the many-worlds theory. Finally, I argue that the wave function realists’ requirement of a local and separable ontology leads them to think of quantum theories as interaction theories, which describe how the fundamental ontology, provided by the non-spatiotemporal wavefunction, behaves. Thus, if this reconstruction is correct, it is unlikely that the realist community will find an agreement on which is the best quantum theory. Lorenzo Lorenzetti (USI) Title: Quantum Physics and Effective Realism Abstract: Three accounts of effective realism (ER) have been advanced to solve three problems for scientific realism: Fraser and Vickers develop a version of ER about non-relativistic quantum mechanics that they argue is compatible with all the main realist versions (‘interpretations’) of quantum mechanics avoiding the problem of underdetermination among them; Williams and Fraser propose ER about quantum field theory as a response to the problems facing realist interpretations; Robertson and Wilson propose ER to deal with the dubious ontological status of the entities belonging to superseded theories. We argue for the unification of these proposals based on realism about modal structure and the idea of scale relativity of ontology developed by ontic structural realists. This solves problems some or all the accounts of ER face, especially that of making explicit in what way they are realist. In this talk we focus in particular on how the ontic structural realist approach to effective realism can be helpful in the context of quantum physics. (based on joint work with James Ladyman) Mario Hubert (Ludwig-Maximilians-University Munich) Title: The Multi-Time Multi-Field Abstract: According to the multi-field interpretation, the quantum mechanical wave-function exists as a physical field in three-dimensional space. Unlike a classical field that assigns values to each point in three-dimensional space, a multi-field assigns values to ordered collections of spatial points. This interpretation has been developed specifically for non-relativistic quantum mechanics, particularly within the non-relativistic de Broglie–Bohm theory (Hubert and Romano, 2018). It offers an alternative to both wave-function realism (Ney, 2021) and the nomological interpretation (Goldstein and Zanghì, 2013), allowing the wave-function to exist as a physical object in the same physical space as particles, similar to the electromagnetic field in classical electromagnetism. I propose to generalize the multi-field concept further into a multi-time multi-field. While a standard multi-field assigns values to ordered collections of spatial points at the same time, a multi-time multi-field assigns values to ordered collections of events in four-dimensional space, where these events need not occur simultaneously and where the space-time structure may not even provide a unique objective time. In the relativistic context, multi-time wave-functions have been developed (Lienert et al., 2020). Following a physical analysis of how multi-time wave-functions work in a relativistic many-worlds theory and relativistic de Broglie–Bohm theory, I will present arguments for interpreting these multi-time wave-functions as multi-time multi-fields. Cristian Mariani (USI) TBC For any queries: associazione.ratio@usi.ch Organisers: Ratio.