Full Idea
Together with a definition of possibility and necessity in terms of counterfactuals, the powers semantics of counterfactuals generates a semantics for modality that appeals to causal powers and not possible worlds.
Gist of Idea
We can base counterfactuals on powers, not possible worlds, and hence define necessity
Source
Jonathan D. Jacobs (A Powers Theory of Modality [2010], §1)
Book Reference
-: 'Philosophical Studies' [-], p.2
A Reaction
Wonderful. Just what the doctor ordered. The only caveat is that if we say that reality is built up from fundamental powers, then might those powers change their character without losing their identity (e.g. gravity getting weaker)?