What’s an Analogy Analogous To?

Supposing somebody didn’t know what an analogy was?  How could he find out?

Could somebody explain it to him by an analogy?  Could somebody say “Look –an analogy bears the same relationship to the thing I am analogizing as does a dream of a river to our waking fear of death, an image in a mirror does to the thing mirrored, tears do the overburdened heart?

How could that help?  Because it would seem to understand the analogy, the person would have to understand what an analogy was already, and thus it would be useless.

And yet we are not born knowing what analogies are.