“What should we think of someone who never admits error, never entertains doubt but adheres unflinchingly to the same ideas all his life, regardless of new evidence? Doubt and skepticism are signs of rationality. When we are too certain of our opinions, we run the risk of ignoring any evidence that conflicts with our views. It is doubt that shows we are still thinking, still willing to reexamine hardened beliefs when confronted with new facts and new evidence.”

“[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.”

“The object of the new school is to teach reasonable doubt. Not the unreasonable doubt of the wild-eyed heckler, but the evidence-based doubt of the questioning scientist and the reason-based doubt of the skilled debater.”

“It is not what we believe, but why we believe it. Moral responsibility lies in diligently weighing the evidence. We must actively doubt; we have to scrutinize our views, not take them on trust. No virtue attached to blindly accepting orthodoxy, however 'venerable'...”

“We take action when we have the honesty to admit that things are still broken, despite our best efforts otherwise. We take action when we hold ourselves continually open to new techniques, remaining resolutely receptive to new sources of support and new feeds of information. We take action when we are willing, in each new moment, to try again.”

“I think we ought always to entertain our opinions with some measure of doubt. I shouldn't wish people dogmatically to believe any philosophy, not even mine. ”