Full Idea
Dispositions can be causes. What is not actual cannot be a cause or any part of a cause. Merely possible events are not actual, and that makes them causally impotent. The claim that powers are causally potent has strong initial plausibility.
Gist of Idea
Dispositions can be causes, so they must be part of the actual world
Source
George Molnar (Powers [1998], 5)
Book Reference
Molnar,George: 'Powers: a study in metaphysics', ed/tr. Mumford,Stephen [OUP 2003], p.101
A Reaction
[He credits Mellor 1974 for this idea] He will need to show how dispositions can be causes (other than, presumably, being anticipated or imagined by conscious minds), which he says he will do in Ch. 12.