Good [[metaphor|metaphors]] rely on some kind of stylistic [[decorum]] or appropriateness. This is your idea that some metaphors are more or less apppropriate than others because, although such metaphors "carry across" separate domains in one sense, in a sense other than those aspects being carried across, the source domain is related to the target. An example of this comes from [this piece](https://theconcourse.deadspin.com/this-guy-truly-has-no-idea-what-hes-talking-about-1838500602) by David Roth about Donald Trump's addled brain and inability to keep his stories straight. Roth compares Trump’s mind to a television tuned to infomercials. > "His mind is a television that changes channels every three seconds and where every channel has an infomercial on it; it cycles day and night without ever quite cohering into a signal. There is plenty of noise, though, and because Trump so utterly lacks discernment he is constantly interrupting himself with some new bit or blurt." From the perspective of the metaphor, there is a transfer across [[domain|domain]]: a mind is not a TV channel. However, in another sense, other than the actual elements being "carried across" by the metaphor, comparing _Donald Trump's_ mind, in particular, to a television channel, is appropriate because of Trump's background as a reality TV personality. The metaphor obviously isn’t random; it’s thematically appropriate because Trump is a reality TV dude. It’s a stretch to say the guy “literally” thinks in terms of TV (hence, metaphor), but it’s probably not _that_ much of a stretch. [[Wayne C. Booth]] alludes to this idea in an article, "[[Booth 1978 - Metaphor as Rhetoric - The Problem of Evaluation|Metaphor as Rhetoric]]": > "==Good metaphors are _appropriate_, in their grandeur or triviality, to the task in hand==. If the point is to heighten sublimity, then trivial metaphors must be avoided. But if diminishment is desired, vice versa. Now in our example what is needed is a heightening of powerful, hypocritical destructiveness on the one hand, and of helpless innocence on the other. On the face of it neither a catfish nor a bass is an especially good metaphor for innocence. But both are innocent enough, and catfish is a bit better than bass for squirming helplessness, since it is not a game fish but an easily caught harmless scavenger" (57) ### Charles Dickens likes to use this... [[Charles Dickens]], [[Dickens's style blurs metaphor and metonymy|whose style is very rich]] uses this technique a lot with his characters. Sometimes it is an aspect of his style, but sometimes there is even a diegetic reason for them. That is, characters use certain kinds of metaphors because, due to their bcackgrounds, they understand the world using certain kinds of schemas. In Dickens's novel, [[Dombey and Son (1846-48)]], Ned Cuttle—or "Captain Cuttle"—does this by constantly invokind nautical metaphors and schemas to understand the world around him. In speech, he says, "Steady!" or "Stand by!" as though carefully directing a ship through treacherous waters. When he is betrayed by Rob the Grinder, the narrator says that Captain Cuttle, > had meant to do his duty by [Rob], and ==had felt almost as kindly towards the boy **as if they had been shipwrecked**== and cast upon a desert place together. And now, that the false Rob had brought distrust, treachery, and meanness into the very parlour, which was a kind of sacred place, ==Captain Cuttle felt **as if the parlour might have gone down next**, and not surprised him much **by its sinking**==, or given him any very great concern. (ch. 39; my emphasis)