“Man is a credulous animal, and must believe something; in the absence of good grounds for belief, he will be satisfied with bad ones.”

“It is not what the man of science believes that distinguishes him, but how and why he believes it. His beliefs are tentative, not dogmatic; they are based on evidence, not on authority or intuition.”

“One of the chief obstacles to intelligence is credulity, and credulity could be enormously diminished by instruction in the prevalent forms of mendacity.”

“I think that in all descriptions of the good life here on earth we must assume a certain basis of animal vitality and animal instinct; without this, life becomes tame and uninteresting. Civilization should be something added to this, not substituted for it; the ascetic saint and the detached sage fail in this respect to be complete human beings. A small number of them may enrich a community; but a world composed of them would die of boredom.”

“I am myself a dissenter from all known religions, and I hope that every kind of religious belief will die out. I do not believe that, on the balance, religious belief has been a force for good. Although I am prepared to admit that in certain times and places it has had some good effects, I regard it as belonging to the infancy of human reason, and to a stage of development which we are now outgrowing.”

“To write tragedy, a man must feel tragedy. To feel tragedy, a man must be aware of the world in which he lives. Not only with his mind, but with his blood and sinews.”

“If a man is offered a fact which goes against his instincts, he will scrutinize it closely, and unless the evidence is overwhelming, he will refuse to believe it. If, on the other hand, he is offered something which affords a reason for acting in accordance to his instincts, he will accept it even on the slightest evidence. The origin of myths is explained in this way.”