George Lakoff discusses metaphor as what he calls 'cross domain mapping'. One conceptual field is read in terms of another. Time is understood in terms of space – “let’s face the future” “let’s put that behind us” etc. Emotion is read as temperature - someone is 'warm' or 'cold'. This is, broadly speaking, a cognitive operation: Metaphor helps us know one ‘domain’ by reading it in terms of another. Conversely, we might argue, for example, that thinking of time in terms of space blocks our true understanding of time – it is miscognition, or misrepresentation.
But perhaps metaphors are shaped not only by their cognitive adequacy, but by the forms of life which they enable, facilitate and produce. The Greeks practised the art of memory. As part of this, it was useful to conceive of memory as a library, with different categories of mnemonic object ‘located’ in different rooms. Yes, this involves seeing a mental faculty as the interior of a building. But the point of this was not at all to better conceptualise what memory was really like (ie correct cognition), it was to improve one’s memory. Conceptualisation was subordinate to function.
Metaphor is typically embedded in a particular form of life , which it helps expedite.