Heather

“[Doubt] is not a new idea; this is the idea of the age of reason. This is the philosophy that guided the men who made the democracy that we live under. The idea that no one really knew how to run a government led to the idea that we should arrange a system by which new ideas could be developed, tried out, and tossed out if necessary, with more new ideas bought in - a trial-and-error system. This method was a result of the fact that science was already showing itself to be a successful venture at the end of the eighteenth century. Even then it was clear to socially minded people that the openness of possibilities was an opportunity, and that doubt and discussion were essential to progress into the unknown. If we want to solve a problem that we have never solved before, we must leave the door to the unknown ajar...doubt is not to be feared, but welcomed and discussed.”
― Richard P. Feynman

“Doubt is an uncomfortable condition, but certainty is a ridiculous one.”
― Voltaire

“I must say a word about fear. It is life's only true opponent. Only fear can defeat life. It is a clever, treacherous adversary, how well I know. It has no decency, respects no law or convention, shows no mercy. It goes for your weakest spot, which it finds with unerring ease. It begins in your mind, always. One moment you are feeling calm, self-possessed, happy. Then fear, disguised in the garb of mild-mannered doubt, slips into your mind like a spy.”
― Yann Martel, Life of Pi

“If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things.”
― René Descartes