premise: we say, a man keeps a good table instead of good <mask>; we read Virgil, that is, his poems; a man has a warm heart, that is, warm affections; a city dweller has no wheels, that is, no automobile.
hypothesis: the best context for <mask> here is A trope in which one word is put for another that suggests it; but not That which is stipulated in advance; a condition; a previous agreement.