Full Idea
Some people claim that modal sentences do not express truths or falsehoods.
Gist of Idea
Maybe modal sentences cannot be true or false
Source
Albert Casullo (A Priori Knowledge [2002], 3.2)
A Reaction
I can only imagine this coming from a narrow hardline empiricist. It seems to me obvious that we make true or false statements about what is possible or impossible.
Book Reference
'Oxford Handbook of Epistemology', ed/tr. Moser, Paul K. [OUP 2002], p.112