Full Idea
A theory of causation might say 'If A had not existed, B would not have existed' (counterfactual theory), or 'B is more likely if A occurs' (probabilistic), or 'energy flows from A to B'.
Clarification
Counterfactuals discuss what might have occurred, rather than what did
Gist of Idea
Causation can be seen in counterfactual terms, or as increased probability, or as energy flow
Source
Tim Crane (Elements of Mind [2001], 2.11)
Book Reference
Crane,Tim: 'Elements of Mind' [OUP 2001], p.41
A Reaction
As always, it is vital to separate epistemology from ontology. Energy won't cover agents. Whisper "Fire!" in a theatre.