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.
Ready for your slide
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 little learning is a dangerous thing”
“A long habit of not thinking a thing wrong gives it a superficial appearance of being right”
“Abandon all hope, ye who enter here”
“All that we see or seem is but a dream within a dream”
“Doubt is not a pleasant condition, but certainty is absurd”
“Doubt is not a pleasant condition, but certainty is an absurd one”
“I can never decide whether my dreams are the result of my thoughts, or my thoughts the result of my dreams”
“I fear the Greeks, even when they bring gifts”
“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 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”
“Nothing is so firmly believed as that which we least know”
“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”
“The mass of men lead lives of quiet desperation”
“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 world is a raving idiot, and no man can kill it”
“The world is a stage, but the play is badly cast”
“We suffer more often in imagination than in reality”
“We are generally the better persuaded by the reasons we discover ourselves than by those given to us by others”
“When you come to a fork in the road, take it”
No public-domain quotes on this theme yet — try another, or use an in-copyright one with attribution.
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.
“Be careful what you water your dreams with. Water them with worry and fear and you will produce weeds that choke the life from your dream”
ReallyAileen Miga & Janice Hughes · not Lao Tzu
“Believe nothing, no matter where you read it or who has said it, not even if I have said it, unless it agrees with your own reason and your own common sense”
ReallyGautama Buddha · not Gautama Buddha
“Bubble bubble, toil and trouble”
ReallyWilliam Shakespeare
“Doubt is the origin of wisdom”
ReallyUnknown — not René Descartes
“Even a stopped clock is right twice a day”
ReallyJoseph Addison · not Paulo Coelho
“Everything we hear is an opinion, not a fact. Everything we see is a perspective, not the truth”
ReallyMarcus Aurelius · not Marcus Aurelius
“Fear is the true enemy, the only enemy”
ReallyHerbert Wright · not Sun Tzu
“I am an old man and have known a great many troubles, but most of them never happened”
ReallyAnonymous saying (later pinned on Mark Twain) · not Seneca
“I awoke, only to find that the rest of the world is still asleep”
ReallySigmund Freud · not Leonardo da Vinci
“I would rather have questions that can't be answered than answers that can't be questioned”
ReallyUnknown (anonymous, popularized c. 2014)
“If that plane leaves the ground and you're not on it, you'll regret it. Maybe not today, maybe not tomorrow, but soon and for the rest of your life”
ReallyJulius J. Epstein, Philip G. Epstein & Howard Koch
“If voting made any difference, they wouldn't let us do it”
ReallyUnknown — an anonymous activist slogan · not Mark Twain
“If you don't read the newspaper, you are uninformed. If you do read the newspaper, you are misinformed”
ReallyUnknown (a late-20th-century coinage) · not Mark Twain
“If you remember the '60s, you really weren't there”
ReallyCharles Fleischer · not Robin Williams
“Impossible is a word to be found only in the dictionary of fools”
ReallyNapoleon Bonaparte
“It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so”
ReallyJosh Billings (Henry Wheeler Shaw) · not Ronald Reagan
“It is the mark of an educated mind to entertain a thought without accepting it”
ReallyNo verified author
“Judge a man by his questions rather than by his answers”
ReallyPierre-Marc-Gaston de Lévis · not Voltaire