“Man once surrendering his reason, has no remaining guard against absurdities the most monstrous, and like a ship without rudder, is the sport of every wind. With such persons, gullibility, which they call faith, takes the helm from the hand of reason, and the mind becomes a wreck.”

“The hocus-pocus phantasm of a God like another Cerberus, with one body and three heads, had its birth and growth in the blood of thousands and thousands of martyrs... In fact, the Athanasian paradox that one is three, and three but one, is so incomprehensible to the human mind, that no candid man can say he has any idea of it, and how can he believe what presents no idea? He who thinks he does, only deceives himself. He proves, also, that man, once surrendering his reason, has no remaining guard against absurdities the most monstrous, and like a ship without a rudder, is the sport of every wind. With such persons, gullibility which they call faith, takes the helm from the hand of reason, and the mind becomes a wreck.[Letter to James Smith discussing Jefferson's hate of the doctrine of the Christian trinity, December 8 1822]”

“Faith is the surrender of the mind, it's the surrender of reason, it's the surrender of the only thing that makes us different from other animals. It's our need to believe and to surrender our skepticism and our reason, our yearning to discard that and put all our trust or faith in someone or something, that is the sinister thing to me. ... Out of all the virtues, all the supposed virtues, faith must be the most overrated”

“The conservative has little to fear from the man whose reason is the servant of his passions, but let him beware of him in whom reason has become the greatest and most terrible of passions. These are the wreckers of outworn empires.”

“The Atheist waits for proof of God. Till that proof comes he remains, as his name implies, without God. His mind is open to every new truth, after it has passed the warder Reason at the gate.”

“Faith is an insertion of absolute conviction that is assume without reason and is defended against all reason.”