Philosophy of Physics Seminar (Thursday - Week 2, HT26)

Abstract: When can geometric structure be fixed via privileged coordinates? This question is of central importance to the debate between dynamics-first and geometry-first approaches to spacetime structure. Advocates of the dynamics-first approach identify privileged coordinates as those in which the dynamical equations take a canonical, simple form. Spacetime geometry is then seen as fixed via the group of transformations between such privileged coordinates.

This talk reviews some technical details required for this approach. Questions addressed include: “When can a group (or pseudogroup) be characterised by privileged coordinates?” (always); and “How does a group fix geometric structure?” (by congruence rather than automorphism). Finally, I review how the congruence structure of an arbitrary inhomogeneous Lorentzian geometry can be fixed group-theoretically, and thus via privileged coordinates, pace Barrett and Manchak (https://doi.org/10.31389/pop.131).

The talk is based on joint work with Henrique Gomes, Tushar Menon, and James Read, and develops https://doi.org/10.48550/arXiv.2408.10674.

Registration: If you do not hold a university card, please contact the seminar convenor or admin@philosophy.ox.ac.uk at least two working days before a seminar to register your attendance.