According to most researchers, [[metonymy]] relies on pre-existing or pre-known referential knowledge. It therefore does _not_ create [[new knowledge]]. (I disagree, but that's a long argument.)
[[Hugh Bredin]]:
> "A metonymy neither states nor implies the connection between the objects involved in it. For this reason, it relies wholly upon those relations between objects that are habitually and conventionally known and accepted. We must __already know__ that the objects are related, if the metonymy is to be devised or understood. Thus, metaphor __creates__ the relation between its objects, while metonymy __presupposes__ that relation. This is why metonymy can never articulate a newly discovered insight, why it lacks the creative depth of metaphor. Metonymy is irresistably and necessarily conventional" ("Metonymy," 57).
[[Stephen Ullmann]] wrote that this basically means, “Metonymy is intrinsically ==less interesting than metaphor==” ([[Semantics - An Introduction to the Science of Meaning (1967)|Semantics]] p. 218).
Ullmann quotes M. Esnault's _Imagination populaire_:
> ‘La métonymie n’ouvre pas des chemins comme l’intuition métaphorique; mais brûlant les étapes de chemins trop connus, elle raccourcit des distances pour faciliter la rapide intuition de choses déjà connues”
Translation (I think Ullmann's):
>“Metonymy does not open new paths like metaphorical intuition; but, taking too familiar paths in its stride, it shortens distances so as to facilitate the swift intuition of things already known” (*Imagination populaire*, p. 31).
Compare what Ullmann quotes to what [[Lilian Furst]] says in [[All Is True (1995)]]:
> “The metonymic figure projects features on a pre-existent chain from one end of the link to the other” (Furst, 161).