Full Idea
Actualism ...debars us from admitting into our ontology the merely possible, not only the merely logically possible, but also the merely physically possible.
Gist of Idea
Actualism means that ontology cannot contain what is merely physically possible
Source
David M. Armstrong (What is a Law of Nature? [1983], 01.3)
Book Reference
Armstrong,D.M.: 'What is a Law of Nature?' [CUP 1985], p.9
A Reaction
This is the big metaphysical question for fans (like myself) of 'powers' in nature. Armstrong declares himself an Actualist. I take it as obvious that the actual world contains powers, but how are we to characterise them?
Related Idea
Idea 17667 Dispositions exist, but their truth-makers are actual or categorical properties [Armstrong]