A cup is useful only when it is empty; and a mind that is filled with beliefs, with dogmas, with assertions, with quotations, is really an uncreative mind.
A pessimist sees only the dark side of the clouds, and mopes; a philosopher sees both sides, and shrugs; an optimist doesn't care. Momentum is wht it wants to gather.
Onecomes to believe whatever one repeats to oneself sufficiently often, whetherthe statement be true or false. It comes to be dominating thought in one'smind.