“Always beware of turning religion into metaphysics: Morality is its essence.”

“Beware the religion that turns you against another one. It's unlikely that it's really religion at all.”

“Religion grants its adherents malign, intoxicating and morally corrosive sensations. Destroying intellectual freedom is always evil, but only religion makes doing evil feel quite so good.”

“Beware when the great God lets loose a thinker on this planet. Then all things are at risk. It is as when a conflagration has broken out in a great city, and no man knows what is safe, or where it will end. There is not a piece of science, but its flank may be turned to-morrow; there is not any literary reputation, not the so-called eternal names of fame, that may not be revised and condemned. The very hopes of man, the thoughts of his heart, the religion of nations, the manner and morals of mankind, are all at the mercy of a new generalization. Generalization is always a new influx of the divinity into the mind. Hence the thrill that attends it.”

“Our basic problem today is that we have two religions in conflict, humanism and Christianity, each with its own morality and the laws of that morality.”

“The essence of any religion is good heart. Sometimes I call love and compassion a universal religion. This is my religion.”