- If p is a precification of q and p is true, then p grounds q.
- If q is vaguely true, then q has a true precification.
- So, every proposition that is vaguely true is grounded.
If we could add the thesis that every grounded proposition is non-fundamental (which in another post I argued against), we could conclude that all vaguely true propositions are non-fundamental. But even without that thesis, groundedness is evidence of non-fundamentality. So vagueness is evidence of non-fundamentality.