I assume the pun is that education is a discipline like any other. Asking questions, gathering evidence, testing hypotheses, publishing, lecturing etc. Not to discredit people who are naturally fantastic at figuring things out along the way. It just isn't the systemic approach academia believes in.
What does academia believe, then? I don't know what the negation of "If you know something you can teach it" is.
That if you don't know something, then you can't teach it?
That if you know something you can't teach it?
That if you don't know something you can teach it?