Most people like to believe something is or is not true. Great scientists tolerate ambiguity very well. They believe the theory enough to go ahead; they doubt it enough to notice the errors and faults so they can step forward and create the new replacement theory. If you believe too much you’ll never notice the flaws; if you doubt too much you won’t get started. It requires a lovely balance.
Richard Hamming (American mathematician, 1915 – 1998) ‘You and Your Research’, Bell Communications Research Colloquium Seminar, 7 Mar 1986.