Contempt is a well-recognized defensive reaction.
Thought is metaphoric, and proceeds by comparison, and the metaphors of language derive therefrom.
A book is a machine to think with.
We want to do something and a definition is a means of doing it. If we want certain results then we must use certain meanings or definitions. But no definition has any authority apart from a purpose, or to bar us from other purposes.
It is never what a poem says that matters, but what it is.
In the simplest formulation, when we use a metaphor we have two thoughts of different things active together and supported by a single word, or phrase, whose meaning is a resultant of their interaction.