"I beseech you, in the bowels of Christ, think it possible you may be mistaken."

-- Oliver Cromwell to a congregation in 1650

"Doubt is not a pleasant condition, but certainty is absurd."

-- Voltaire

"Ah, what a dusty answer gets the soul
When hot for certainties in this our life!"

-- George Meredith, Modern Love

"To be absolutely certain about something, one must know everything or nothing about it."

-- Olin Miller

"In the case of any person whose judgment is really deserving of confidence, how has it become so? Because he has kept his mind open to criticism of his opinions and conduct. Because it has been his practice to listen to all that could be said against him; to profit by as much of it as was just, and expound to himself, and upon occasion to others, the fallacy of what was fallacious. Because he has felt, that the only way in which a human being can make some approach to knowing the whole of a subject, is by hearing what can be said about it by persons of every variety of opinion, and studying all modes in which it can be looked at by every character of mind. No wise man ever acquired his wisdom in any mode but this; nor is it in the nature of human intellect to become wise in any other manner."

-- John Stuart Mill, "On Liberty"

"The difficulty is to realize the groundlessness of our believing."

-- Ludwig Wittgenstein, On Certainty

"As far as the laws of mathematics refer to reality, they are not certain; as far as they are certain, they do not refer to reality."

-- Albert Einstein, In an address to the Prussian Academy of Science in Berlin, Jan 27, 1921

"There is room for words on subjects other than last words...Only the refusal to listen guarantees one against being ensnared by the truth."

-- Robert Nozick, Anarchy, State And Utopia

"Reasons for support or for doubt are all mortals can hope for. Final conclusions, like final solutions, are for dogmatists."

-- Murray Edelman, Constructing The Political Spectacle