Reference Frames and the Ontology of General Relativity. Re(l)ality: The View From Nowhere vs. The View From Everywhere

Understand

In General Relativity, the genuine observable quantities are gauge-invariant Dirac observables.

• One well-known method of constructing them is relational, using reference frames.
• This leaves open an interpretive question: how should we understand two distinct relational observables defined relative to two distinct frames? I argue that this question admits two equally precise answers, corresponding to two distinct ontologies for relational general-relativistic physics, both expressible within a single fibre-bundle vocabulary.
• Central to the analysis is a distinction -- building on Wallace (2019) -- between frame-independence and frame-freedom, which disambiguates appeals to perspective-'neutrality'.