## 2023-2024

Upcoming talks

13 April 2024

**Eleanor March (Oxford)**, **“Are Maxwell gravitation and Newton-Cartan theory theoretically equivalent?”**

Abstract: A recent flurry of work has addressed the question whether Maxwell gravitation and Newton-Cartan theory are theoretically equivalent. I defend the view that there are plausible interpretations of Newton-Cartan theory on which the answer to the above question is ‘yes’. Along the way, I seek to clarify what is at issue in this debate. In particular, I argue that whether Maxwell gravitation and Newton-Cartan theory are equivalent has nothing to do with counterfactuals about unactualised matter, *contra* the appearance of previous discussions in the literature. Nor does it have anything to do with spacetime and dynamical symmetries, *contra* recent claims by Jacobs (2023). Instead, it depends on some rather subtle questions concerning how facts about the geodesics of a connection acquire physical significance, and the distinction between dynamical and kinematical possibility.

A preprint of Eleanor’s paper is available here.

25 May 2024

**Lu Chen (USC)**

Past Events

27-28 October 2023

**Event: **Symmetry and Structure Workshop**Register by October 20: **https://forms.gle/r8pMXxWXALQ3MNZs8

3-4 November 2023

**Event: **Conceptual and Mathematical Foundations of Science**Register by October 27: **https://forms.gle/9FQ2YytDRWfu7Pg87

9 December 2023

**Jeffrey Barrett (UCI) and Eddy Chen (UCSD), “Algorithmic Randomness and Probabilistic Laws**“

Abstract: We consider two ways one might use algorithmic randomness to characterize a probabilistic law. The first is a generative chance* law. Such laws involve a nonstandard notion of chance. The second is a probabilistic* constraining law. Such laws impose relative frequency and randomness constraints that every physically possible world must satisfy. While each notion has virtues, we argue that the latter has advantages over the former. It supports a unified governing account of non-Humean laws and provides independently motivated solutions to issues in the Humean best-system account. On both notions, we have a much tighter connection between probabilistic laws and their corresponding sets of possible worlds. Certain histories permitted by traditional probabilistic laws are ruled out as physically impossible. As a result, such laws avoid one variety of empirical underdetermination, but the approach reveals other varieties of underdetermination that are typically overlooked.

A preprint is available: https://arxiv.org/pdf/2303.01411.pdf

13 January 2024

**Lev Vaidman (Tel Aviv), “Transfer of quantum information in teleportation”**

Abstract: The controversial issue of information transfer in quantum teleportation procedure is analyzed in the framework of the many-worlds interpretation of quantum mechanics. In contrast to the claims of Deutsch & Hayden 2000, it is argued that quantum information, considered as a measurable property for an observer in a particular world, is transferred in a nonlocal way in the teleportation process. This, however, does not lead to action at a distance on the level of the universe which includes all parallel worlds.

Preprint: https://philsci-archive.pitt.edu/21447/

~~24 February 2024~~ **TALK POSTPONED TO 28 September 2025**

**Joshua Eisenthal (Caltech)**, **“The Absolute Motion Detector”**

Abstract: Following the proliferation of non-Euclidean geometries in the nineteenth century, the “problem of space” emerged as the problem of demarcating which mathematical geometries were candidate physical geometries. By around 1900, a consensus formed around the following purported solution. The possibility of measuring spatial magnitudes depends on the possibility of moving rigid bodies (such as rulers and compasses) without changing their dimensions. As only the constant curvature geometries could represent this kind of rigid transport, only these geometries were candidate physical geometries — or so the argument went. However, it was only after the development of general relativity in 1915 that the physical significance of transport along affine geodesics was understood. When an object moves inertially it moves along an affine geodesic, but if this takes place in a curved space, those geodesics do not stay a fixed distance apart. Thus an extended object will experience elastic tension when it moves in a curved space, even when there are no forces acting on it. In this talk I will explore what impact this insight might have had for the nineteenth century problem of space. In particular, I will explore the consequences for the two main positions in the philosophy of geometry in this period: geometrical empiricism (the view that experiments determine which geometry is “true”) and geometrical conventionalism (the view that we ourselves must decide, based on simplicity and convenience, which geometry is best to use).