Full Idea
One can only be sure that a proposition expresses a genuine logical possibility if one can be sure that one's concepts are adequate to things referred to in the proposition.
Gist of Idea
Logical possibility needs the concepts of the proposition to be adequate
Source
Stephen Boulter (Why Medieval Philosophy Matters [2019], 4)
Book Reference
Boulter,Stephen: 'Why Medieval Philosophy Matters' [Bloomsbury 2019], p.104
A Reaction
Boulter says this is a logical constraint place on logical possibility by the scholastics which tends to be neglected by modern thinkers, who only worry about whether the proposition implies a contradiction. So we now use thought experiments.