Published Papers
On Symmetries and Springs, Philosophy of Science, forthcoming (published)
Imagine that we are on a train playing with some mechanical systems. Why can’t we detect any differences in their behavior when the train is parked versus when it is moving uniformly? The standard answer is that boosts are symmetries of Newtonian systems. In this paper, I use the case of a spring to argue that this answer is problematic because symmetries are neither sufficient nor necessary for preserving its behavior. I also develop a new answer according to which boosts preserve the relational properties on which the behavior of a system depends, even when they are not symmetries.
Symmetries and Representation (with Geoffrey Hall), Philosophy Compass, forthcoming (published)
It is often said in physics that if two models of a theory are related by a symmetry, then the two models provide (or could provide) two different representations of the very same situation, alike the case of two maps of different color for the very same city. It is also said that the situations represented by two models of a theory are indiscernible in some ways when the models in question are related by a symmetry of the theory, just like the situation in the interior of the cabin of a train when the train is at rest in the station is empirically indiscernible from the situation in the interior when the train is moving uniformly (in classical mechanics, these two situations are represented by two models related by a boost). In recent years, philosophers of physics have focused a lot of attention in developing various principles that aim to elucidate these and similar remarks on symmetries, models, physical equivalence, and representation that are widespread in physics practice. The goal of the current article is to provide a critical review of these principles, and suggest a new framework for thinking about these kinds of questions. One important upshot of the paper is that questions of indiscernibility, and questions of the representational capacity of models, must be distinguished from one another.
Causation and the conservation of energy in general relativity (with James Read and Andrés Páez), The British Journal for the Philosophy of Science, forthcoming (preprint)
Consensus in the contemporary philosophical literature has it that conserved quantity theories of causation such as that of Dowe [2000]—according to which causation is to be analysed in terms of the exchange of conserved quantities (e.g., energy)—face damning problems when confronted with contemporary physics, where the notion of conservation becomes delicate. In particular, in general relativity it is often claimed that there simply are no conservation laws for (say) total-stress energy. If this claim is correct, it is difficult to see how conserved quantity theories of causation could survive. In this article, we resist the above consensus and defend conserved quantity theories from this conclusion,
at least when focusing on the apparent problems posed by general relativity. We argue that this approach to causation can continue to be defended in general relativity, once one appreciates (a) the availability of approximate symmetries in generic general relativistic
spacetimes, and (b) the role of modeling and idealisation in that theory. Given these points, conserved quantity theories of causation must stand or fall on other grounds.
The Next Generation Event Horizon Telescope Collaboration: History, Philosophy, and Culture (with Galison, P., Doboszewski, J., Elder, J., Martens, N. C., Ashtekar, A … & Wüthrich, A.), Galaxies, 2023 (published)
This white paper outlines the plans of the History Philosophy Culture Working Group of the Next Generation Event Horizon Telescope Collaboration.
A puzzle concerning local symmetries and their empirical significance, The British Journal for the Philosophy of Science, 2022 (published, preprint)
In the last five years, the controversy about whether or not gauge transformations can be empirically significant has intensified. On the one hand, Greaves and Wallace (2014) developed a framework according to which, under some circumstances, gauge transformations can be empirically significant—and Teh (2015) further supported this result by using the Constrained Hamiltonian formalism. On the other hand, Friederich (2015, 2016) claims to have proved that gauge transformation can never be empirically significant. In this paper, I accomplish two tasks. First, I argue that there are strong reasons to resist Friederich’s proof because one of its assumptions is, at the very least, highly controversial. Second, I argue that, despite criticism by Brading and Brown (2004) and Friederich (2015), ‘t Hooft’s Beam-Splitter experiment is indeed a concrete example of a case where a local gauge symmetry has empirical significance. By shedding light on these two points, this paper shows that recent arguments that claim gauge transformations cannot be empirically significant are not satisfactory.
On how Epistemological Letters changed the foundations of Physics, Oxford Handbook of the History and Interpretations of Quantum Mechanics (ed. Olival Freire), 2022 (published, preprint)
It is not an exaggeration to say that the 1970s marked the beginning of a new era in the foundation of quantum mechanics. These were the years when physicists and philosophers interested in the foundations of physics started to actively engage with the conceptual and empirical implications of the Bell inequality, published in 1964. Among other things, the first experiments designed to test whether quantum mechanics violated the inequality in question were carried out during these years and two journals —Foundations of Physics and Epistemological Letters— dedicated to the foundations of physics were created. Although all this is well-known, not much has been said about the exact ways that Epistemological Letters, in particular, helped the foundations of quantum mechanics consolidate as an important and respectable scientific discipline. And this is precisely the subject of the present paper. As I will argue here, at least four features of Epistemological Letters encouraged the foundations of quantum mechanics to flourish during a time when the discipline itself was not very well respected by the broader physics community: one, the kind of interdisciplinary research Epistemological Letters and the institution behind it so insistently encouraged; second, and related, their efforts for reaching out to anybody interested in the foundations of quantum mechanics, regardless of their department, position, or “academic status”; third, the fact that the journal explicitly promoted the informal confrontation of ideas; fourth, and more obviously, its very high quality—some of the most important papers on the foundations of quantum mechanics were first published in Epistemological Letters.
Abandoning Galileo’s Ship: The quest for non-relational empirical significance (with Nicholas Teh), The British Journal for the Philosophy of Science, 2021 (published, preprint)
The recent debate about whether gauge symmetries can be empirically significant has focused on the possibility of ‘Galileo’s ship’ types of scenarios, where the symmetries effect relational differences between a subsystem and the environment. However, it has gone largely unremarked that apart from such Galileo’s ship scenarios, Greaves and Wallace (2014) proposed that gauge transformations can also be empirically significant in a ‘non-relational’ manner that is analogous to a Faraday-cage scenario, where the subsystem symmetry is related to a change in a charged boundary state. In this paper, we investigate the question of whether such non-relational scenarios are possible for gauge theories. Remarkably, the answer to this question turns out to be closely related to a foundational puzzle that has driven a host of recent developments at the frontiers of theoretical physics. By drawing on these recent developments, we show that a very natural way of elaborating on Greaves and Wallace’s claim of non-relational empirical significance for gauge symmetry is incoherent. However, we also argue that much of what they suggest is correct in spirit: one can indeed construct non-relational models of the kind they sketch, albeit ones where the empirical significance is not witnessed by a gauge symmetry but instead by a superficially similar boundary symmetry. Furthermore, the latter casts doubt on whether one really abandons Galileo’s ship in such scenarios.
Measuring Absolute Velocity (with Ben Middleton), Australasian Journal of Philosophy (2020)
We argue that Roberts’s argument for the thesis that absolute velocity is not measurable in a Newtonian world is unsound, because it depends on an analysis of measurement that is not extensionally adequate. We propose an alternative analysis of measurement, one that is extensionally adequate and entails that absolute velocity is measured in at least one Newtonian world. If our analysis is correct, then this Newtonian world is a counterexample to the widely endorsed thesis that if a property varies under the symmetries of a theory then, according to that theory, the property could not be measured. Thus, our paper shows that the debate over the measurability of symmetry-variant properties is more unsettled than previously supposed.
Separating Einstein’s Separability, Studies in the History and Philosophy of Modern Physics (2020)
In this paper, I accomplish a conceptual task and a historical task. The conceptual task is to argue that (1) Einstein’s Principle of Separability (henceforth “separability”) is not a supervenience principle and that (2) separability and entanglement are compatible. I support (1) by showing that the conclusion of Einstein’s incompleteness argument would still follow even if one assumes that the state of a composite system does not supervene on the states of the subsystems, and by showing that what Einstein says in “Quantum Mechanics and Reality” (1948) strongly suggests that separability is not a principle about how subsystem states relate to the state of composite systems. I support (2) by showing that if separability was incompatible with entanglement, then Einstein’s argument would be incoherent in a trivial way. Thus, by arguing for (1) and (2) I directly challenge what has been, and still is, a very common reading of separability. The historical task is to offer the first detailed review of the different ways in which separability has been defined by physicists and philosophers in the last 60 years. Among other things, such a review distinguishes three different definitions of the principle, and shows that since the 1990s and up until the present date, it became standard to take separability (as presented by Einstein) to be a supervenience principle.
A weak values approach for testing simultaneous Einstein-Podolsky-Rosen elements of reality for non-commuting observables (with Calderón-Losada, O., Quistian, T. T. M., Cruz-Ramirez, H., U’Ren, A. B., Botero, A., & Valencia, A), Communications Physics (2020)
In questioning the completeness of quantum mechanics, Einstein–Podolsky–Rosen (EPR) claimed that from the outcomes of local experiments performed on an entangled system, it was possible to ascribe simultaneous reality to the values of certain incompatible observables. As EPR acknowledged, the inevitable disturbance of quantum measurements prevents the precise verification of these assertions on a single system. However, the EPR elements of reality can still be tested at the ensemble level through weak measurements—which minimally disturb the measured system—by interpreting the EPR assertions as assertions about weak values that follow from the outcomes of projective measurements. Here, we report an implementation of such a test through joint weak measurements followed by post-selection on polarization-entangled photon pairs. Our results show that there is a correspondence between the obtained joint weak values and the inferred elements of reality in the polarization version of the EPR assertions.