James Weatherall

In this two-part essay, we distinguish several senses in which general relativity has been regarded as “locally special relativistic.” Here, in Part 1, we focus on senses in which a relativistic spacetime has been said to be “locally (approximately) Minkowskian.” After critiquing several proposals in the literature, we present a result capturing a substantive sense in which every relativistic spacetime is locally approximately Minkowskian. We then show that Minkowski spacetime is not distinguished in this result: every relativistic spacetime is locally approximately every other spacetime in the same sense. In Part 2, we will consider “locally specially relativistic” matter theories.

It is widely accepted by physicists and philosophers of physics alike that there are certain contexts in which general relativity will “break down”. In such cases, one expects to need some as-yet undiscovered successor theory. This paper will discuss certain pathologies of general relativity that might be taken to signal that the theory is breaking down, and consider how one might expect a successor theory to do better. The upshot will be an unconventional interpretation of the “Strong Cosmic Censorship Hypothesis”.

In this two-part essay, we distinguish several senses in which general relativity has been regarded as “locally special relativistic.” In Part 1, we focused on senses in which a relativistic spacetime may be said to be “locally (approximately) Minkowskian.” Here, in Part 2, we consider what it might mean to say that a matter theory is “locally special relativistic.” We isolate and evaluate three criteria in the literature and show that they are incompatible: matter theories satisfying one will generally violate others. We then consider what would happen if any of those criteria failed for a given theory.