The paper “Pure shape dynamics: general framework” has just been published in Classical and Quantum Gravity. Check out the publications section for the details.
New Publication!
The essay titled “The physics and metaphysics of pure shape dynamics” has been published in the edited collection “The Foundations of Spacetime Physics: Philosophical Perspectives” (Routledge). See the publications section for the details.
New Publication!
The paper “A proposal for a metaphysics of self-subsisting structures. I. Classical physics” has just been published in Synthese. Check out the publications section for the details.
Warsaw Spacetime Colloquium: Chen & Goldstein (3 June on Zoom)
On Friday, 3 June, Eddy Keming Chen (UC San Diego) and Sheldon Goldstein (Rutgers) will give a talk titled “Governing Without A Fundamental Direction of Time: Minimal Primitivism about Laws of Nature” (abstract below).
The meeting will be online on Zoom (17:00-19:00 CEST). If you have not registered yet, you can do so here.
The videos of the previous meetings are available on YouTube.
You can address any inquiry to antonio.vassallo@pw.edu.pl.
ABSTRACT
The Great Divide in metaphysical debates about laws of nature is between Humeans who think that laws merely describe the distribution of matter and non-Humeans who think that laws govern it. The metaphysics can place demands on the proper formulations of physical theories. It is sometimes assumed that the governing view requires a fundamental/intrinsic direction of time: to govern, laws must be dynamical, producing later states of the world from earlier ones, in accord with the fundamental direction of time in the universe. In this paper, we propose a minimal primitivism about laws of nature (MinP) according to which there is no such requirement. On our view, laws govern by constraining the physical possibilities. Our view captures the essence of the governing view without taking on extraneous commitments about the direction of time or dynamic production. Moreover, as a version of primitivism, our view requires no reduction/analysis of laws in terms of universals, powers, or dispositions. Our view accommodates several potential candidates for fundamental laws, including the principle of least action, the Past Hypothesis, the Einstein equation of general relativity, and even controversial examples found in the Wheeler-Feynman theory of electrodynamics and retrocausal theories of quantum mechanics. By understanding governing as constraining, non-Humeans who accept MinP have the same freedom to contemplate a wide variety of candidate fundamental laws as Humeans do.
#You are encouraged but not required to read the preprint before attending the talk: https://arxiv.org/pdf/2109.09226.pdf
Warsaw Spacetime Colloquium: Carl Hoefer (20 May on Zoom)
On Friday, 20 May, Carl Hoefer (ICREA and University of Barcelona) will give a talk titled “Much Ado About Nothing: The Dubious Roles of Points in the Metaphysics of Spacetime” (abstract below).
The meeting will be online on Zoom (17:00-19:00 CEST). If you have not registered yet, you can do so here.
The videos of the previous meetings are available on YouTube.
You can address any inquiry to antonio.vassallo@pw.edu.pl.
ABSTRACT
In a new generation of work on the Hole argument and the right way to formulate substantivalism, the tiniest things of all continue to play an outsized role. In my talk, I will discuss some of the mischiefs that philosophers cause with points, and then offer some reflections on how we might try to re-think the issues.
Warsaw Spacetime Colloquium: Lam & Oriti (6 May on Zoom)
On Friday, 6 May, Vincent Lam (University of Bern & Grenoble Alpes University) and Daniele Oriti (Ludwig Maximilian University of Munich) will give a talk titled “The Laws of Quantum Gravity” (abstract below).
The meeting will be online on Zoom (17:00-19:00 CEST). If you have not registered yet, you can do so here. The program for this semester is here. The videos of the previous meetings are available on YouTube.
You can address any inquiry to antonio.vassallo@pw.edu.pl.
ABSTRACT
Several approaches in quantum gravity suggest radical revisions of the standard notion of spacetime, and even its disappearance from the fundamental level of description. We discuss traditional conceptions of laws of nature in the light of these new suggestions about spacetime, and why they become untenable, and we indicate some possible ways to characterize the laws of nature in this quantum gravity context.
Warsaw Spacetime Colloquium: Juliusz Doboszewski (22 April on Zoom)
On Friday, 22 April, Juliusz Doboszewski (University of Bonn) will give a talk titled “No ‘No Go’ for LIGO Prediction” (abstract below).
The meeting will be online on Zoom (17:00-19:00 CEST). If you have not registered yet, you can do so here.
You can address any inquiry to antonio.vassallo@pw.edu.pl.
ABSTRACT
Some authors have claimed that prediction is “essentially impossible” in general relativity. But what is the scope and importance of the formal results underlying the claim? I will discuss this issue in the context of predictions tested in gravitational-wave astronomy, and show how the experimental setup of the LIGO collaboration avoids the “no go” theorem; this sheds new light on some of the more subtle ways in which physicists use general relativity in making predictions.
Warsaw Spacetime Colloquium: Nick Huggett (8 April on Zoom)
On Friday, 8 April, Nick Huggett (University of Illinois Chicago) will give a talk titled “Gravity meets the Quantum in the Laboratory” (abstract below).
The meeting will be online on Zoom (17:00-19:00 CEST). If you have not registered yet, you can do so here.
You can address any inquiry to antonio.vassallo@pw.edu.pl.
ABSTRACT
The characteristic – Planck – energy scale of quantum gravity is utterly beyond current technology, making experimental access to the relevant physics apparently impossible. Nevertheless, low energy experiments linking gravity and the quantum have been undertaken: the Page and Geilker quantum Cavendish experiment, and the Colella-Overhauser-Werner neutron interferometry experiment, say. However, neither probes states in which gravity remains in a coherent quantum superposition – unlike recent proposals that have created considerable interest among physicists. In essence, if two initially unentangled systems interacting solely via gravity become entangled, then, according to a simple theorem of quantum mechanics, gravity must quantum. Clearly there are formidable challenges to creating such a system, but remarkably, tabletop technology into the gravitational fields of very small bodies has advanced to the point that such an experiment might be feasible in the next several years. In this talk I will explain the proposal and what it aims to show, highlighting the important ways in which it is theory-laden. (Drawn from joint work with Niels Linnemann and Mike Schneider.)
Warsaw Spacetime Colloquium: Samuel C. Fletcher (25 March on Zoom)
On Friday, 25 March, Samuel C. Fletcher (University of Minnesota, Twin Cities) will give a talk titled “What Gravitational Waves Really Teach Us about Energy” (abstract below).
The meeting will be online on Zoom (17:00-19:00 CET). If you have not registered yet, you can do so here.
You can address any inquiry to antonio.vassallo@pw.edu.pl.
ABSTRACT
Gravitational wave solutions to the Einstein field equation of general relativity are commonly regarded as examples proving how gravity in general relativity transmits energy from a source body to a distant body. The famous 1955 Feynman sticky bead thought experiment illustrates the reality of this phenomenon by imagining two beads generating heat in a rod on which they slide with friction, due to their changing proper distance in the presence of the waves. I argue that while this lesson is not entirely wrong, it is much too simplistic. It does not reconcile its conclusion with the fact that conservation of local energy-momentum, in the sense that appears in the field equation, prevents energy transmission across a vacuum. Thus “energy transmission” must employ a different concept of energy, raising the possibility of pluralism with regard to the energy concept. Another (compatible) possibility is that gravitational waves, rather than transmitting energy, facilitate the transformation between different types or stores of energy locally. Key to these possibilities is analysis of the Weyl tensor. Time permitting, I discuss these possibilities’ implications for a re-evaluation of the scope of Mach’s Principle, the idea that the distribution of matter determines the geometry of spacetime.
Warsaw Spacetime Colloquium: Claudio Calosi (11 March on Zoom)
On Friday, 11 March, Claudio Calosi (University of Geneva) will give a talk titled “Out of all the Indifferences, into One Thing: On Wavefunction Monism” (abstract below).
The meeting will be online on Zoom (17:00-19:00 CET). If you have not registered yet, you can do so here.
You can address any inquiry to antonio.vassallo@pw.edu.pl.
ABSTRACT
Wavefunction Monism is a peculiar combination of monism and realism about the wavefunction. I provide the first systematic assessment of the view, highlighting benefits and costs. This assessment, I contend, sheds new light on different forms of (quantum) monism.