Full Idea
No man can consider a thing which he does not conceive.
Gist of Idea
We must first conceive things before we can consider them
Source
Thomas Reid (Essays on Intellectual Powers 5: Abstraction [1785], 6)
Book Reference
Reid,Thomas: 'Inquiry and Essays', ed/tr. Beanblossom /K.Lehrer [Hackett 1983], p.247
A Reaction
This seems to imply concepts, but we should not take this to be linguistic, since animals obviously consider things and make judgements.