A symbol is indeed the only possible expression of some invisible essence, a transparent lamp about a spiritual flame; while allegory is one of many possible representations of an embodied thing, or familiar principle, and belongs to fancy and not to imagination: the one is a revelation, the other an amusement.
William Butler YeatsAll art is in the last analysis an endeavor to condense as out of the flying vapor of the world an image of human perfection, and for its own and not for the art's sake.
William Butler Yeats