Relativity Is Not About Spacetime

TL;DR

This paper argues that relativity is fundamentally about the observational equivalence of different spacetime descriptions in quantum theory, not about spacetime's ontological features or local causality.

Contribution

It challenges the common assumption that relativity's core is about spacetime's structure, emphasizing its role in quantum observational equivalence rather than local causality.

Findings

Relativity does not guarantee local causality.

Spacetime descriptions are observationally equivalent in quantum theory.

Relativity reflects probabilistic nature of quantum phenomena.

Abstract

Quantum measurement predictions are consistent with relativity for macroscopic observations, but there is no consensus on how to explain this consistency in fundamental terms. The prevailing assumption is that the relativistic structure of spacetime should provide the framework for any microphysical account. This bias is due, in large part, to our intuitions about local causality, the idea that all physical processes propagate through space in a continuous manner. I argue that relativity is not a guarantor of local causality, and is not about ontological features of spacetime. It is, rather, an expression of the observational equivalence of spacetime descriptions of physical processes. This observational equivalence is due to the essentially probabilistic nature of quantum theory.