"No disorders have employed so many quacks, as those that have no cure; and no sciences have exercised so many quills,…"

"In this world nothing can be said to be certain, except death and taxes."

"The quest for certainty blocks the search for meaning. Uncertainty is the very condition to impel man to unfold his p…"

"Certainty has become a consumer product. It is marketed the world over–by insurance companies, investment advisers, e…"

"A common fallacy in much of the adverse criticism to which science is subjected today is that it claims certainty, in…"

"Certainty generally is illusion, and repose is not the destiny of man."

"I believe that we do not know anything for certain, but everything probably."

"A woman's guess is much more accurate than a man's certainty."

"We may not be able to get certainty, but we can get probability, and half a loaf is better than no bread."

"Certainty is the mark of the common-sense life: gracious uncertainty is the mark of the spiritual life. To be certain…"