“Our thought is independent of the metaphors we employ, in so far as these metaphors are optional,” Lewis wrote, “that is, in so far as we are able to have the same idea without them.”
But when it comes to understanding and communicating the great, bewildering truths of science, there are no ideas but in analogies.
Analogy comes only after the facts.
To know that the tale of two corks is an accurate comparison, Feynman must already have known how electromagnetic fields operate.