All posts by nickhggtt

New Video

We have just posted some new videos to our YouTube channel: a 100-level lecture on spacetime from Tushar Menon and James Read, and a pair of 200-level lectures on dualities by Keizo Matsubara. There is also a stack of new talks, including Erik Curiel’s Two Paths to the Einstein Field Equation from Horizon Thermodynamics. Find the link above, or from the speaker page above. Enjoy!


Midwest Summer School – final call!

The deadline for student applications for the summer school in Chicago is Monday, March 19th. We can confirm that there will be no registration fee: meals and accommodation will be provided without cost to students. Details are here:


We note the passing of Stephen Hawking, whose contributions to our field cannot be calculated (not even using zeta function regularization). To mention one item beautiful work, that influenced me, and which not everyone seems to know, there is the series of contrasting lectures and dialogues with Roger Penrose (and others): The Nature of Space and Time. So full of insights, and revealing of their different personal axioms, but so understanding and respectful of each other, I thoroughly recommend it in many ways.

A different kind of work, Hawking is the titular star of the most recent installment (the hexagonal phase) of The Hitchhiker’s Guide to the Galaxy. Also recommended in many ways.

Curiel speaks this week!

Wednesday 7 March 2018 at UIC – Erik Curiel (LMU/Harvard):  Two Paths to the Einstein Field Equation from Horizon Thermodynamics

Abstract: “There are today two major research programs that attempt to derive
general relativity—the Einstein field equation—from the thermodynamical properties of causal horizons, that based on the work of Jacobson and that on the work of Padmanabhan, both inspired by and relying on the framework of black-hole thermodynamics.  Each has had tantalizing, and similar, successes.  It does not seem to be widely recognized in the literature, however, that there are deep differences between the two, both in mathematical form and in conceptual foundation.  In this talk, I compare the two with the particular aim of teasing out what exactly each takes to be the thermodynamical properties of horizons.  The hope is that the differences between the two, and how they arrive at their common goal, may shed light on different ways one may conceive of “purely gravitational” phenomena as being thermodynamical in character, and what it may even mean in the first place to impute thermodynamical characteristics to purely gravitational systems.  I also discuss technical and conceptual problems with the approaches, whose resolutions—or even just their sustained attempt—would provide great insight on all these issues as well.” In terms of technical difficulty, this talk rates 4/5 (in parts).

More info in Speakers tab above.

Talk: Lucy James

• Wednesday 28 February 2018 at Geneva – Lucy James (Bristol): What does fundamentality mean and what is its relevance for quantum gravity?

Abstract: I begin with giving some motivation for thinking of fundamentality as being relative or comparative, rather than absolute, in philosophy, with particular emphasis on the philosophy of physics. This results in a fundamentality relation which has the logical structure of a strict partial order. I briefly discuss this logical structure and then go on to explain how it applies to some specific cases where the idea of fundamentality is used in the literature. The overall aim is to establish when this relation holds, what its relata are, and which direction the relation points in between a given pair of relata. To this end, I distinguish two categories of relata: theories and things. I also categorise the relation into an epistemic and a formal or semantic fundamentality relation, which do not always agree about which direction to point when holding between the same pair of relata. I present further problems with attempting to define an overarching metaphysical fundamentality relation before finally giving some positive suggestions for how all of this bears on the quantum gravity problem. In terms of technical difficulty, this talk rates 2/52.


We are very sad to learn of the death of Joseph Polchinski. His work, including his String Theory textbook, is very important to many philosophers thinking about string theory, and he was generous with his time and intellect with our community. He will be missed.

The statement from UCSB is here:…Professor.Emeritus.Joseph.Polchinski

The terrific paper that he wrote for Studies in History and Philosophy of Modern Physics is here:

Summer school 2018!

After the success of our Summer School two years ago, we are very pleased to announce that the Space and Time After Quantum Gravity project will be a major component of the First Biennial Midwest Summer School in Philosophy of Physics, to be held in Chicago in late July. We hope that there will be no cost to students to attend.

More details and a call for applications can be found above or here:

Please join us!

New video: Richard Healey: The loopy world of gauge theories

Science journalist George Musser sat down with philosopher of physics Richard Healey to discuss the meaning of gauge theories, the basis of our modern understanding of force and matter. For all their predictive power, these theories leave us in the dark about the basic ingredients of the physical world.

On our channel or at

Lam December 20th

• Wednesday 20 December 2017 at Geneva – Vincent Lam (Geneva): Perspectives from general relativity and quantum gravity on laws of nature and causation

Attention: This talk will exceptionally be in room L208 (Landolt, second floor).

Abstract: This talk aims to update and enrich the two main families of metaphysical conceptions—reductive and non-reductive ones—about laws of nature and causation with insights from fundamental spacetime and gravitational physics. One of the crucial implications of the dynamical nature of general relativistic spacetime is that the global spacetime topology can be non-trivial in a way that may be at odds with the temporal (and ‘production’) aspects of non-reductive accounts. We will discuss the status of the global topological constraints that may be imposed on the spacetime structure within the reductive and non-reductive conceptions about laws and causation. Furthermore, we will specifically discuss how the non-linear and elliptic (constrained) structure of general relativity raises difficulties in evaluating counterfactuals in the initial value formulation of the theory. We will conclude with considerations on how to generalize the standard conceptions about laws and causation to the quantum gravity context where spacetime may not be fundamental in some sense. In terms of technical difficulty, this talk mostly rates 1/5 (with a few peaks) 1