The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts.
How dreadful are the curses which Mohammedanism lays on its votaries! Besides the fanatical frenzy, which is as dangerous in a man as hydrophobia in a dog, there is a fateful fatalistic apathy.
The devil's bride, Reason, that pretty whore, comes in and thinks she's wise, and what she says, what she thinks, is from the Holy Spirit, who can help us, then? Not judges, not doctors, no king or emperor, because reason is the Devil's greatest whore.
Believe those who seek the truth; doubt those who find it.
Original French: “Croyez ceux qui cherchent la vérité, doutez de ceux qui la trouvent.”
People seem very arrogant when they say 'I'm right and you're wrong', but in practice we all believe we're right. We have a staggering arrogance in our own belief. That can be tempered by not being 100% certain; by being provisional. No matter what the debate is, very few people have the modesty to suspend judgement on a whole range of things; most intelligent people have an opinion and are expected to have an opinion by other people - but it always requires making a personal judgement that goes way-beyond your expertise. We do it all the time.
A wise man changes his mind, a fool never does.
The obstinate Man does not hold Opinions; they hold him.
The history of Western science confirms the aphorism that the great menace to progress is not ignorance but the illusion of knowledge.
There is only one step from fanaticism to barbarism.
A fanatic is one who can't change his mind and won't change the subject.
Attributed
The demand for certainty is one which is natural to man, but is nevertheless an intellectual vice. So long as men are not trained to withhold judgment in the absence of evidence, they will be led astray by cocksure prophets, and it is likely that their leaders will be either ignorant fanatics or dishonest charlatans. To endure uncertainty is difficult, but so are most of the other virtues.
It is always easier to deny reality than to allow our worldview to be shattered, a fact that was as true of die-hard Stalinists at the height of the purges as it is of libertarian climate change deniers today.
If you believe free speech is for you but not your political opponents, you're illiberal. If no contrary evidence could change your beliefs, you're a fundamentalist. If you believe the state should punish those with contrary views, you're a totalitarian. If you believe political opponents should be punished with violence or death, you’re a terrorist.
More frightening than any particular beliefs or policies is an utter lack of any sense of a need to test those beliefs and policies against hard evidence. Mistakes can be corrected by those who pay attention to facts, but dogmatism will not be corrected by those who are wedded to a vision.
To Dogmatism the Spirit of Inquiry is the same as the Spirit of Evil.
There is no possible reply to these heads-I-win-and-tails-you-lose assertions, except to note that they would justify any policy on any subject anywhere, regardless of its empirically observed consequences. In short, no matter what happens, the vision of the anointed always succeeds, if not by the original criteria, then by criteria extemporized later—and if not by empirical criteria, then by criteria sufficiently subjective to escape even the possibility of refutation. Evidence becomes irrelevant.
From the saintly and single-minded idealist to the fanatic is often but a step.
Even today, I frequently meet scientists who, outside their own narrow discipline, are superstitious.
The fanatic is incorruptible: if he kills for an idea, he can just as well get himself killed for one; in either case, tyrant or martyr, he is a monster.
He who begins by loving Christianity better than truth, will proceed by loving his own sect or church better than Christianity, and end in loving himself better than all.
Certainty is the enemy of mankind. If you're certain about everything, you have the Inquisition, you have Nazis and you have - that certainty is something to be guarded about.
Never attempt to reason with people who know they are right!
Nothing can be more hateful than the uncharitableness of the Puritans, who condemn … to eternal torments, even the most inoffensive proselytes to popery.
Pigheaded covers a multitude of virtues - as well as sins.
An excessive knowledge of Marxism is a sign of a misspent youth.