The Metaphysics of Machian Frame-Dragging

TL;DR

This paper explores the metaphysical nature of Machian frame-dragging in general relativity, proposing a new dependence relation that is intermediate between causation and grounding, using structural equation models and counterfactual analysis.

Contribution

It introduces a novel dependence relation to better understand frame-dragging, bridging causal and grounding explanations in a metaphysical context.

Findings

Frame-dragging is best understood via a new dependence relation.

The relation is half-way between causation and grounding.

Structural equation models clarify the metaphysical dependence.

Abstract

The paper investigates the kind of dependence relation that best portrays Machian frame-dragging in general relativity. The question is tricky because frame-dragging relates local inertial frames to distant distributions of matter in a time-independent way, thus establishing some sort of non-local link between the two. For this reason, a plain causal interpretation of frame-dragging faces huge challenges. The paper will shed light on the issue by using a generalized structural equation model analysis in terms of manipulationist counterfactuals recently applied in the context of metaphysical enquiry by Schaffer (2016) and Wilson (2017). The verdict of the analysis will be that frame-dragging is best understood in terms of a novel type of dependence relation that is half-way between causation and grounding.