Full Idea
The only plausible link from conceivability to possibility is via ideal conceivability.
Gist of Idea
Only ideal conceivability could indicate what is possible
Source
Jonathan Schaffer (Causation and Laws of Nature [2008], n22)
Book Reference
'Contemporary Debates in Metaphysics', ed/tr. Sider/Hawthorne/Zimmerman [Blackwell 2008], p.102
A Reaction
[He cites Chalmers 2002] I'm not sure what 'via' could mean here. Since I don't know any other way than attempted conceivability for assessing a possibility, I am a bit baffled by this idea.