Relational Observables, Quiddities, and Structural Realism

TL;DR

This paper explores how relational observables in modern physics inform modal and non-modal features of reality, advancing the understanding of structural realism and addressing philosophical issues in lawhood and modality.

Contribution

It introduces the concept that relational observables in general relativity and quantum gravity support a form of modal ontic structural realism, linking modal and non-modal aspects of reality.

Findings

Relational observables help connect modal and non-modal features of reality.

The 'internal view' concept offers insights into lawhood and modality.

Modern physics challenges traditional accounts of modality.

Abstract

In this article, I argue that modern spacetime physics causes problems for a number of traditional accounts of modality, but also offers important new ideas about the connection between modal and non-modal features of reality. I suggest that recent work on relational observables in general relativity and quantum gravity can help us understand how non-modal features of reality could arise from modal features of reality within some form of modal ontic structural realism. In particular, I argue that the notion of an `internal view,' as employed in the partial/complete observables formalism and the quantum reference frame formalism, is an important conceptual insight which can help address outstanding problems in the philosophy of lawhood and modality.