Sentient observers and the ontology of spacetime

TL;DR

This paper argues that the structure of spacetime cannot be uniquely identified through observables, suggesting a deep link between spacetime and observer sentience, challenging certain philosophical positions.

Contribution

It demonstrates that spacetime structure is inherently relative and cannot be fully captured by observables, highlighting a connection between spacetime and observer sentience.

Findings

Spacetime structure is not uniquely observable.

The relationship between observables and physical properties is relative.

Spacetime structure is verified to be non-relative and unique.

Abstract

I show that, by the same criteria that led to Galilean and Special Relativity and gauge symmetries, there is no way to identify a unique set of observables that give the structure of space or spacetime. In some sense, space is lost in the state space itself. Moreover, the relationship between the observables and the physical properties they represent becomes relative. But we can verify that they are not relative, and the spacetime structure is unique. I show that this implies that not all structures isomorphic with observers can be observers, contradicting Structural Realism and Physicalism. This indicates a strong connection between spacetime and the sentience of the observers, as anticipated by some early contributors to Special and General Relativity.