We know, of course, that the great discoveries - the true and noble paradoxes - have always come from men who by long prenticeship have so far mastered the tools forged by their fathers that they were not tied down to one particular way of using them; we know that Jove's head cannot crack with Minerva unless he have previously swallowed Metis.
Mathematical Papers, Review of A Budget of Paradoxes (p. 560)