Full Idea
Forrest proposed that structural universals should serve as ersatz possible worlds.
Clarification
'Ersatz' implies a stand-in
Gist of Idea
Structural universals might serve as possible worlds
Source
report of Peter Forrest (Ways Worlds Could Be [1986]) by David Lewis - Against Structural Universals 'Intro'
Book Reference
Lewis,David: 'Papers in Metaphysics and Epistemology' [CUP 1999], p.78
A Reaction
I prefer powers to property universals. Perhaps a possible world is a maximal set of co-existing dispositions?