Belief in the truth commences with the doubting of all those "truths" we once believed.
Friedrich Nietzsche

In heaven all the interesting people are missing.
Friedrich Nietzsche

Faith, indeed, has up to the present not been able to move real mountains ... But it can put mountains where there are none.
Friedrich Nietzsche

The snake which cannot cast its skin has to die. As well the minds which are prevented from changing their opinions; they cease to be mind.
Friedrich Nietzsche

Digressions, objections, delight in mockery, carefree mistrust are signs of health; everything unconditional belongs in pathology.
Friedrich Nietzsche

Some claims deserve ridicule, and anything less falsely elevates them.
Steven Novella

If liberty means anything at all, it means the right to tell people what they do not want to hear.
George Orwell

One defeats a fanatic precisely by not being a fanatic oneself, but on the contrary by using one's intelligence.
George Orwell

In times of universal deceit, telling the truth is a revolutionary act.
George Orwell

The greater the ignorance, the greater the dogmatism.
William Osler

When men yield up the privilege of thinking, the last shadow of liberty quits the horizon.
Thomas Paine

Is it more probable that nature should go out of her course or that a man should tell a lie? We have never seen, in our time, nature go out of her course. But we have good reason to believe that millions of lies have been told in the same time. It is therefore at least millions to one that the reporter of a miracle tells a lie.
Thomas Paine

To argue with a man who has renounced the use and authority of reason [...] is like giving medicine to the dead.
Thomas Paine

As to the book called the Bible, it is blasphemy to call it the word of God. It is a book of lies and contradictions, and a history of bad times and bad men. There are but a few good characters in the whole book.
Thomas Paine

I have always strenuously supported the right of every man to his own opinion, however different that opinion might be to mine. He who denies to another this right, makes a slave of himself to his present opinion, because he precludes himself the right of changing it.
Thomas Paine

Science is the only way of knowing - everything else is superstition.
Robert Park

For if the trumpet give an uncertain sound, who shall prepare himself to the battle? So likewise ye, except ye utter by the tongue words easy to be understood, how shall it be known what is spoken?
St Paul - 1 Corinthians 14:8,9

I perceive that in all things ye are too superstitious.
St Paul - Acts 17:22

Now faith is the substance of things hoped for, the evidence of things not seen.
St Paul - Hebrews 11:1

Perfect as the wing of a bird may be, it will never enable the bird to fly if unsupported by the air. Facts are the air of science. Without them a man of science can never rise.
Ivan Pavlov

Write on my gravestone: "Infidel, Traitor." - infidel to every church that compromises with wrong; traitor to every government that oppresses the people.
Wendell Phillips

Sometimes you can see things happen right in front of your eyes and still jump to the wrong conclusions.
Jodi Picoult

It's natural to think that living things must be the handiwork of a designer. But it was also natural to think that the sun went around the earth. Overcoming naïve impressions to figure out how things really work is one of humanity's highest callings.
Steven Pinker

When one person suffers from a delusion, it is called insanity. When many people suffer from a delusion it is called religion.
Robert M Pirsig

All religion is simply evolved out of fraud, fear, greed, imagination, and poetry
Edgar Allen Poe

It is the simple hypotheses of which one must be most wary; because these are the ones that have the most chances of passing unnoticed.
Henri Poincaré

Thinking must never submit itself, neither to a dogma, nor to a party, nor to a passion, nor to an interest, nor to a preconceived idea, nor to whatever it may be, if not to facts themselves, because, for it, to submit would be to cease to be.
Henri Poincaré

Science is facts; just as houses are made of stones, so is science made of facts; but a pile of stones is not a house and a collection of facts is not necessarily science.
Henri Poincaré

Science must begin with myth and with the criticism of myth.
Karl Popper

We should therefore claim, in the name of tolerance, the right not to tolerate the intolerant.
Karl Popper

If we are not prepared to defend a tolerant society against the onslaught of the intolerant, then the tolerant will be destroyed, and tolerance with them.
Karl Popper

I have insisted that we must be tolerant. But I also believe that this tolerance has its limits. We must not trust those anti-humanitarian religions which not only preach destruction but act accordingly. For if we tolerate them, then we become ourselves responsible for for their deeds.
Karl Popper

We all remember how many religious wars were fought for a religion of love and gentleness; how many bodies were burned alive with the genuinely kind intention of saving souls from the eternal fire of hell.
Karl Popper

True ignorance is not the absence of knowledge, but the refusal to acquire it.
Karl Popper

Science is not about building a body of known 'facts'. It is a method for asking awkward questions and subjecting them to a reality-check, thus avoiding the human tendency to believe whatever makes us feel good.
Terry Pratchett

Science is best defined as a careful, disciplined, logical search for knowledge about any and all aspects of the universe, obtained by examination of the best available evidence and always subject to correction and improvement upon discovery of better evidence. What's left is magic. And it doesn't work.
James Randi

The New Age? It's just the old age stuck in a microwave oven for fifteen seconds.
James Randi

Coincidence is the science of the true believer.
Chet Raymo

When I see a bird that walks like a duck and swims like a duck and quacks like a duck, I call that bird a duck.
James Whitcomb Riley

I contend that we are both atheists. I just believe in one fewer god than you do.
Stephen Roberts

The sure way to be cheated is to think one's self more cunning than others.
François de La Rochefoucauld

Broad-minded is just another way of saying a fellow's too lazy to form an opinion.
Will Rogers

When will our consciences grow so tender that we will act to prevent human misery rather than avenge it?
Eleanor Roosevelt

You could claim that anything's real if the only basis for believing in it is that nobody's proved it doesn't exist!
J. K. Rowling

The opinions that are held with passion are always those for which no good ground exists; indeed the passion is the measure of the holders lack of rational conviction. Opinions in politics and religion are almost always held passionately
Bertrand Russell

Almost everything that distinguishes the modern world from earlier centuries is attibutable to science.
Bertrand Russell

Not to be absolutely certain is, I think, one of the essential things in rationality.
Bertrand Russell

Fear is the main source of superstition & one of the main sources of cruelty. To conquer fear is beginning of wisdom.
Bertrand Russell

Fear is the main source of superstition, and one of the main sources of cruelty. To conquer fear is the beginning of wisdom.
Bertrand Russell

So far as I can remember, there is not one word in the Gospels in praise of intelligence.
Bertrand Russell