Theme
Doubt
Skepticism, questioning, and thinking for yourself.
Every quote here is provenance-checked. AI will happily put a fake quote on a beautiful slide — these are the ones you can actually use, with the right name on them.
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Verified quotes about doubt
Each is traced to a real source and correctly credited. ✓ Free to use = public domain, cleared for commercial reuse. Open one for a paste-ready credit line and its reuse status.
“A cynic is a man who knows the price of everything and the value of nothing”
“A little learning is a dangerous thing”
“A long habit of not thinking a thing wrong gives it a superficial appearance of being right”
“A man who lies to himself and listens to his own lie comes to a point where he does not discern any truth”
“A quotation is a handy thing to have about, saving one the trouble of thinking for oneself, always a laborious business”
“Abandon all hope, ye who enter here”
“Absence of evidence is not evidence of absence”
“All that we see or seem is but a dream within a dream”
“Blind belief in authority is the greatest enemy of truth”
“But the best evidence we have that time travel is not possible, and never will be, is that we have not been invaded by hordes of tourists from the future”
“Custom is a violent and treacherous schoolmistress”
“Democracy is the theory that the common people know what they want, and deserve to get it good and hard”
“Doubt is not a pleasant condition, but certainty is absurd”
“Doubt is not a pleasant condition, but certainty is an absurd one”
“Every individual is an exception to the rule”
“Extraordinary claims require extraordinary evidence”
“History is more or less bunk”
“Hope in reality is the worst of all evils, because it prolongs the torments of man”
“I can never decide whether my dreams are the result of my thoughts, or my thoughts the result of my dreams”
“I do not believe in God, because I believe in man”
“I do not feel obliged to believe that the same God who has endowed us with senses, reason, and intellect has intended us to forgo their use”
“I don't want to belong to any club that will accept me as a member”
“I fear the Greeks, even when they bring gifts”
“I know of no country in which there is so little independence of mind and real freedom of discussion as in America”
“I really didn't say everything I said”
“I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail”
“I think our society is run by insane people for insane objectives”
“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”
“If you absolutely can't tolerate critics, then don't do anything new or interesting”
“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”
“If you've been in the game 30 minutes and you don't know who the patsy is, you're the patsy”
“Live the questions now. Perhaps you will then gradually, without noticing it, live along some distant day into the answer”
“Nothing is so firmly believed as that which we least know”
“Our doubts are traitors, and make us lose the good we oft might win, by fearing to attempt”
“Question with boldness even the existence of a God; because, if there be one, he must more approve the homage of reason, than that of blindfolded fear”
“Risk comes from not knowing what you're doing”
“The first principle is that you must not fool yourself — and you are the easiest person to fool”
“The mass of men lead lives of quiet desperation”
“The nine most terrifying words in the English language are: I'm from the Government, and I'm here to help”
“The sad truth is that most evil is done by people who never make up their minds to be good or evil”
“The test of a first-rate intelligence is the ability to hold two opposed ideas in mind at the same time”
“The truth is rarely pure and never simple”
“The world is a raving idiot, and no man can kill it”
“The world is a stage, but the play is badly cast”
“There can be no doubt that Saddam Hussein has biological weapons and the capability to rapidly produce more, many more”
“There is nothing quite so tragic as a young cynic, because it means the person has gone from knowing nothing to believing nothing”
“Think about how stupid the average person is, and then realize that half of 'em are stupider than that”
“To be, or not to be, that is the question”
“We can judge our progress by the courage of our questions and the depths of our answers, our willingness to embrace what is true rather than what feels good”
“We suffer more often in imagination than in reality”
“When the anecdotes and the data disagree, the anecdotes are usually right”
“when you are a Bear of Very Little Brain, and you Think of Things, you find sometimes that a Thing which seemed very Thingish inside you is quite different when it gets out into the open and has other people looking at it”
“When you gaze long into an abyss the abyss also gazes into you”
“Wonder is the feeling of a philosopher, and philosophy begins in wonder”
“You're gonna need a bigger boat”
“Common Sense Is Nothing More Than a Deposit of Prejudices Laid Down in the Mind Before Age Eighteen”
“Few people think more than two or three times a year; I have made an international reputation for myself by thinking once or twice a week”
“Gold Gets Dug Out of the Ground; Then We Melt It Down, Dig Another Hole, Bury It Again”
“I never get the accountants in before I start up a business. It's done on gut feeling, especially if I can see that they are taking the mickey out of the consumer”
“If all the girls who attended the Yale prom were laid end to end, I wouldn't be at all surprised”
“If there is a God, he will have to beg my forgiveness”
“If you hear a voice within you say you cannot paint, then by all means paint, and that voice will be silenced”
“In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual”
“Men never do evil so completely and cheerfully as when they do it from religious conviction”
“Republicans buy sneakers, too”
“Show me a sane man and I will cure him for you”
“The great question that has never been answered, and which I have not yet been able to answer, despite my thirty years of research into the feminine soul, is 'What does a woman want?'”
“The longer I live, the more I am inclined to the belief that this earth is used by other planets as a lunatic asylum”
“We are generally the better persuaded by the reasons we discover ourselves than by those given to us by others”
“When a subject becomes totally obsolete we make it a required course”
“When you come to a fork in the road, take it”
“You can lead a horticulture, but you can't make her think”
“You can't teach an old dogma new tricks”
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Don’t get caught out
Commonly shared about doubt — but misattributed
Popular doubt lines that get pinned on the wrong name. If you use one, credit it correctly.
“Beatles Rejection: We Don't Like Their Sound. Groups of Guitars Are On Their Way Out”
ReallyDick Rowe · not Brian Epstein
“I Understand It Brings You Luck, Whether You Believe in It or Not”
ReallyNiels Bohr · not Albert Einstein
“The One Who Follows the Crowd Will Usually Go No Further Than the Crowd”
ReallyAlan Ashley-Pitt · not Albert Einstein
“No One Can Win at Roulette Unless He Steals Money from the Table While the Croupier Isn't Looking”
ReallyTed Thackrey, Jr. · not Albert Einstein
“We Don't Know Who Discovered Water, But We Know It Wasn't a Fish”
ReallyJohn M. Culkin · not Albert Einstein
“Any field that has the word science in its name is guaranteed thereby not to be a science”
ReallyFrank Harary · not Richard Feynman
“If you think you understand quantum mechanics, you don't understand quantum mechanics”
ReallyRichard Feynman · but not in these words
“The philosophy of science is as useful to scientists as ornithology is to birds”
ReallyUnknown · not Richard Feynman
“When the Facts Change, I Change My Mind. What Do You Do, Sir?”
ReallyJohn Maynard Keynes · not Winston Churchill
“It Will Take Them Ten Years to Prove Me Wrong”
ReallyUnknown · not Winston Churchill
“News Is What Somebody Does Not Want You To Print. All the Rest Is Advertising”
ReallyUnknown · not George Orwell
“History Does Not Repeat Itself. The Historians Repeat One Another”
ReallyMax Beerbohm · not Oscar Wilde
“An Anecdote Is A Revealing Account of an Incident That Never Occurred in the Life of Some Famous Person”
ReallyAnonymous · not Bennett Cerf
“Do You Want Six or Eight Slices of Pizza?”
ReallyUnknown (an unsigned 1965 newspaper joke) · not George Carlin
“Education Is the Inculcation of the Incomprehensible Into the Ignorant by the Incompetent”
ReallyNo verified originator · not John Maynard Keynes
“Every Dogma Has Its Day”
ReallyAnonymous · not Anthony Burgess
“Everybody Talks About the Weather, But Nobody Does Anything About It”
ReallyCharles Dudley Warner · not Mark Twain
“I Wish I Was As Sure of Any One Thing As He is of Everything”
ReallyWilliam Lamb, 2nd Viscount Melbourne · not Benjamin Disraeli