Full Idea
Truth only belongs to propositions: whereof there are two sorts, viz. mental and verbal
Gist of Idea
Truth only belongs to mental or verbal propositions
Source
John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 4.05.02)
Book Reference
Locke,John: 'Essay Concerning Human Understanding', ed/tr. Nidditch,P.H. [OUP 1979], p.574
A Reaction
I think it is important to retain 'mental' propositions, so that animals are allowed to think correctly or wrongly about things. I don't think Locke gives much thought to the ontological status of propositions.