Deflating the Spacetime-Matter Dichotomy

TL;DR

This paper challenges the traditional spacetime-matter dichotomy in scalar-tensor theories, showing that scalar fields cannot be neatly categorized as either spacetime or matter, and proposes a decoupling of spacetime from gravity.

Contribution

It provides a critical analysis of the spacetime-matter dichotomy within scalar-tensor theories and suggests a new perspective on the ontological status of spacetime and gravity.

Findings

The spacetime-matter dichotomy is untenable in scalar-tensor theories.

Scalar fields in these theories cannot be classified solely as matter or spacetime.

The concept of spacetime can be decoupled from gravity in this context.

Abstract

In this paper we analyse scalar-tensor theories-specific instances of which include mainstream inflation and dark energy models-in light of the spacetime-matter dichotomy. We argue that it is difficult to categorise the scalar fields as either a pure aspect of the spacetime structure or a pure form of matter, by focusing on the Jordan vs Einstein frames of these theories. We present and evaluate various interpretational options available, concluding that the spacetime-matter dichotomy becomes untenable in this context. At the same time, the ontological and conceptual category of spacetime can be decoupled from that of gravity, with the latter remaining viable in the context of scalar-tensor theories.