Metaphors and the Absurd

Hobbes in Chapter iv-v discusses "absurdities" in language, which are contradictions or improper usages of words that render them nonsense. The example of the round quadrangle is obvious, but his dismissal of metaphors is troubling. Hobbes' main gripe with metaphor is that it is constituted by words in "other sense than they are ordained for" (iv, 4). Therefore the phrase "heart of stone" is absurd to Hobbes because it neither refers to a real heart nor anything actually made of rock.

Does Hobbes not understand the ambiguity inherent in most symbolic forms of communication? He seems to not acknowledge the role of connotation in language. Connotation is what gives metaphor power and meaning, and so metaphor is not as simply absurd and meaningless as Hobbes suggests.

This doesn't answer the question of why metaphors are sometimes preferred, though. Some may be unnecessary and distracting, but I think other metaphors have the ability to capture nuance and can also serve as a symbolic umbrella for emotions or details that would be otherwise hard to describe. Hobbes might respond by claiming that these nuances and details could in fact be explained (perhaps longwindedly) and that metaphor is still imprecise. I am not sure this is true; perhaps some situations or thoughts are damaged by extensive explanation, and so metaphor is the closest possible approximation to the subject.

Also, what does Hobbes think about the role of art, if even the imprecision of metaphor is criticized?