Metaphor states a mystery. It collapses the membrane between the thing itself and the image of it. The formulation is that of an equation, X=Y. But unlike mathematical equations, metaphor participates in absurdity, because X is also utterly different from Y. Say the moon is a thumbtack in the sky. A the risk of belabouring the obvious, the moon is not like a thumbtack in most senses. It does not feel hard and it cannot be held in your hand, for example. But for a fleeting moment you see the two terms of the metaphor as married and you understand the truth, which is a third thing, which is transcendent, beyond either of the two terms. I believe now that metaphor, which a cannot be taken literally because it has paradox at its heart, must be our most accurate way of starting the transcendent.
-Jeanne Murray Walker: Saving Images