"If a man will begin with certainties, he shall end in doubts; but if he will be content to begin with doubts he shall end in certainties."
— Francis Bacon

"To learn which questions are unanswerable, and not to answer them: this skill is most needful in times of stress and darkness."
— Ursula K. LeGuin (The Left Hand of Darkness)

"One of the few certainties in life is that persons of certainty should certainly be avoided."
— Willy Russell (The Wrong Boy)

"To voice doubts was unthinkable, but that did not means that doubts did not exist."
— John Christopher (The Pool of Fire)

"Certainty is the most vivid condition of ignorance and the most necessary
condition for knowledge."
— Kedar Joshi

"Why do people resist [engines, bridges, and cities] so? They are symbols and products of the imagination, which is the force that ensures justice and historical momentum in an imperfect world, because without imagination we would not have the wherewithal to challenge certainty, and we could never rise above ourselves."
— Mark Helprin (Winter's Tale)

"It (trying to keep the law) grants you the power to judge others and feel superior to them. You believe you are living to a higher standard than those you judge. Enforcing rules, especially in its more subtle expressions like responsibility and expectation, is a vain attempt to create certainly out of uncertainty. And contrary to what you might think, I have a great fondness for uncertainty. Rules cannot bring freedom; they only have the power to accuse. "
— William P. Young (The Shack)

"In these matters, the only certainty is that nothing is certain"
— Pliny the Elder (Naturalis Historia, Vol. VI CB)