Full Idea
To claim that the truthmaker for a counterfactual, for example, is a set of possible worlds, but to deny that these worlds really exist, seems pointless.
Gist of Idea
It is pointless to say possible worlds are truthmakers, and then deny that possible worlds exist
Source
C.B. Martin (The Mind in Nature [2008], 03.3)
Book Reference
Martin,C.B.: 'The Mind in Nature' [OUP 2008], p.26
A Reaction
Lewis therefore argues that they do exist. Martin argues that possible worlds are not truthmakers. He rests his account of modality on dispositions. I prefer Martin.