On the geometric trinity of gravity, non-relativistic limits, and Maxwell gravitation

We show that the dynamical common core of the recently-discovered non-relativistic geometric trinity of gravity is Maxwell gravitation. More- over, we explain why no analogous distinct dynamical common core exists in the case of the better-known relativistic geometric trinity of gravity

Is the Deutsch-Wallace theorem redundant?

I defend the Deutsch-Wallace (DW) theorem against a dilemma presented by Dawid and Thebault (2014), and endorsed in part by Read (2018), and Brown and Porath (2020), according to which the theorem is either redundant or in conflict with general frequency-to-chance inferences. I argue that neither horn of the dilemma is well-posed. On the one hand, the DW theorem is not in conflict with general frequency-to-chance inferences on the most natural way of stating the theorem. On the other hand, the DW theorem is crucial for establishing the Born rule as a prediction of Everettian quantum mechanics (EQM), and so cannot be redundant within the theor

Non-relativistic twistor theory: Newtonian limits and gravitational collapse

Recently, Dunajski and Gundry (2016) have developed an extension of twistor theory to the non-relativistic domain. Unlike relativistic twistor theory, their approach is able to reproduce the entire space of models of Newton-Cartan theory. I critically assess the significance of non-relativistic twistors, in particular with respect to proposals by Dunajski and Penrose (2023) that using non-relativistic twistors to describe gravitationally induced collapse could play a part in solving the quantum measurement problem

Many worlds or one: reply to Steeger

Steeger (2022) has recently claimed that Bohmians are able to make use of the Deutsch-Wallace derivation of quantum-mechanical chance values. I argue that Steeger's proposal does not succeed, but a close cousin of it - for de Broglie-Bohm epistemic probabilities - does. This clarifies the relationship between Born rule probabilities in Everettian quantum mechanics and de Broglie-Bohm theory, as well as the scope of the Deutsch-Wallace theorem

Are Maxwell gravitation and Newton-Cartan theory theoretically equivalent?

A recent flurry of work has addressed the question whether Maxwell gravitation and Newton-Cartan theory are theoretically equivalent. This paper defends 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 kinematic possibility

On coordinate-based and coordinate-free approaches to Newtonian gravitation on Maxwellian spacetime

I discuss and clarify the relationship between the recent wave of 'intrinsic' coordinate-free approaches to Maxwell gravitation and the coordinate-based discussions of Saunders (2013) and Wallace (2020)

On the geometric trinity of gravity, non-relativistic limits, and Maxwell gravitation

We show that the common core of the recently-discovered non-relativistic geometric trinity of gravity is Maxwell gravitation. Moreover, we explain why no such dynamical common core exists in the case of the better-known relativistic geometric trinity of gravity