Full Idea
The main issue with learning possibility from conceivability concerns how we can be confident that we have conceived things to the relevant level of depth required for the scenario to actually be a presentation or manifestation of a genuine possibility.
Gist of Idea
How do you know you have conceived a thing deeply enough to assess its possibility?
Source
Anand Vaidya (The Epistemology of Modality [2015], 1.2.2)
Book Reference
'Stanford Online Encyclopaedia of Philosophy', ed/tr. Stanford University [plato.stanford.edu], p.4
A Reaction
[He cites Van Inwagen 1998 for this idea] The point is that ignorant imagination can conceive of all sorts of absurd things which are seen to be impossible when enough information is available. We can hardly demand a criterion for this.