The demand for certainty is one which is natural to man, but is nevertheless an intellectual vice. If you take your hypothesis seriously enough, it will generate predictions; and if the predictions are wrong, you must abandon the hypothesis. To seek for certainty where the subject-matter does not permit it is to mistake the nature of the inquiry.

The task, then, is not so much to see what no one has yet seen, but to think what nobody has yet thought about that which everybody sees.