Anchoring Causal Connections in Physical Concepts

In their paper How Fundamental Physics Represents Causality Andreas Bartels and Daniel Wohlfarth maintain that there is place for causality in General Relativity. Their argument contains two steps: first they show that there are time-asymmetric models in General Relativity, then they claim to derive that two events are causally connected if and only if there is a time-asymmetric energy flow from one event to the other. In our comment we first give a short summary of their paper followed by a section introducing and pondering different conceptions of causation since Bartels and Wohlfarth don’t explicitly declare which notion of causation they build on in the paper. In order to analyze their argument in detail we formalize their crucial step in logical terms. This helps to pose the question whether their proposed derivation is not just a definition in a more precise way.