Well, I was rather a cynic once. But now I've combined all my beliefs into this phrase I've been circulating: "Religion is the most malevolent of all mind viruses." It's adapted from a phrase by the British writer and scientist Richard Dawkins, who said that religion was a mind virus, an idea that infected the mind. He said that not all mind-viruses are malignant; some may even be beneficial. But many are harmful—racist theories, for instance.

From an Interview with Arthur C. Clark. February 18, 2004, The Onion, Volume 40, Issue 07.

Questioner: How do you recognize the truth when it is upon us?

Carl Sagan: A simple question: How can we recognize the truth? It is, of course, difficult. But there are a few simple rules. The truth ought to be logically consistent. It should not contradict it self; that is, there are some logical criteria. It ought to be consistent with what else we know. That is an additional way in which miracles run into trouble. We know a great many things a tiny fraction, to be sure, of the universe, a pitifully tiny fraction. But nevertheless some things we know with quite high reliability.  So where we are asking about the truth, we ought to be sure that it's not inconsistent with what else we know. We should also pay attention to how badly we want to believe a given contention.  The more badly we want to believe it, the more skeptical we have to be. It involves a kind of courageous self-discipline. Nobody says it's easy I think those three principles at least will winnow out a fair amount of chaff. It doesn't guarantee that what remains will be true, but at least it will significantly diminish the field of discourse.

From "The Varieties of Scientific Experience, a personal view of the search for God" by Carl Sagan, edited by Ann Druyan, the Penguin Press, New York, 2006. Selected Q&A from Chapter Five, page 229

You might almost define a good scientist as a person with the horse sense to discern the largest answerable question ----- and to shun useless issues that sound bigger.

Stephen J. Gould
Natural History Magazine
This View of Life

"It appears to me (whether rightly or wrongly) that direct arguments against christianity and theism produce hardly any effect on the public; and freedom of thought is best promoted by the gradual illumination of men's minds which follows from the advance of science." [Darwin]

"If we believe absurdities, we shall commit atrocities." [Voltaire]

"I cannot imagine a God who rewards and punishes the objects of his creation, whose purposes are modeled after our own -- a God, in short, who is but a reflection of human frailty. Neither can I believe that the individual survives the death of his body, although feeble souls harbor such thoughts through fear or ridiculous egotism." [Einstein]

"Faith means not wanting to know what is true." [Nietzsche]

"I cannot believe in the immortality of the soul.... No, all this talk of an existence for us, as individuals, beyond the grave is wrong. It is born of our tenacity of life – our desire to go on living … our dread of coming to an end." [Edison]

"The Bible is not my book nor Christianity my profession. I could never give assent to the long, complicated statements of Christian dogma." [Lincoln]

"Religion is a byproduct of fear. For much of human history, it may have been a necessary evil, but why was it more evil than necessary? Isn't killing people in the name of God a pretty good definition of insanity?" [Arthur C. Clarke]

"Religions are all alike – founded upon fables and mythologies." [Thomas Jefferson]

"Say what you will about the sweet miracle of unquestioning faith, I consider a capacity for it terrifying and absolutely vile." [Kurt Vonnegut]

"Religion is based . . . mainly on fear . . . fear of the mysterious, fear of defeat, fear of death. Fear is the parent of cruelty, and therefore it is no wonder if cruelty and religion have gone hand in hand. . . . My own view on religion is that of Lucretius. I regard it as a disease born of fear and as a source of untold misery to the human race." [Bertrand Russell]

"Religious institutions that use government power in support of themselves and force their views on persons of no faith, undermine all our civil rights - Erecting the "wall of separation between church and state," therefore, is absolutely essential in a free society." [Thomas Jefferson]