This last paragraph of this essay by C.S. Lewis has about a thousand implications for language, poetry, reason, meaning, certainty, speaking, thinking and anything we do that involves those concepts and skills. We can draw out those implications later. This is good enough for now:
It will have escaped no one that in such a scale of writers the poets will take the highest place; and among the poets those who have at once the tenderest care for old words and the surest instinct for the creation of new metaphors. But it must not be supposed that I am in any sense putting forward the imagination as the organ of truth. We are not talking of truth, but of meaning: meaning which is the antecedent condition both of truth and falsehood, whose antithesis is not error but nonsense. I am a rationalist. For me, reason is the natural organ of truth; but imagination is the organ of meaning. Imagination, producing new metaphors or revivifying old, is not the cause of truth, but its condition. It is, I confess, undeniable that such a view indirectly implies a kind of truth or rightness in the imagination itself. I said at the outset that the truth we won by metaphor could not be greater than the truth of the metaphor itself; and we have seen since that all our truth, or all but a few fragments, is won by metaphor. And thence, I confess, it does follow that if our thinking is ever true, then the metaphors by which we think must have been good metaphors. It does follow that if those original equations, between good and light, or evil and dark, between breath and soul and all the others, were from the beginning arbitrary and fanciful–if there is not, in fact, a kind of psycho-physical parallelism (or more) in the universe–then all our thinking is nonsensical. And so, admittedly, the view I have taken has metaphysical implications. But so has every view.