The more intense has been the religion of any period and the more profound has been the dogmatic belief, the greater has been the cruelty and the worse has been the state of affairs.

Never let yourself be diverted, either by what you wish to believe, or what you think could have beneficent social effects if it were believed; but look only and solely at what are the facts.

Protestants, from the first, have been distinguished from their opponents by what they do not believe; to throw over one more dogma is, therefore, merely to carry the movement one stage further. Moral fervor is the essence of the matter.

What makes a free thinker is not his beliefs, but the way in which he holds them. If he holds them because his elders told him they were true when he was young, or if he holds them because if he did not he would be unhappy, his thought is not free; but if he holds them because, after careful thought, he finds a balance in their favor, then his thought is free, however odd his conclusions may seem.

[Industrialism's soon diminishing] capacity to supply human needs could be prevented if men exercised any restraint or foresight in their present frenzied exploitation.

I am as firmly convinced that religions do harm as I am that they are untrue.

One should as a rule respect public opinion in so far as is necessary to avoid starvation and to keep out of prison, but anything that goes beyond this is voluntary submission to an unnecessary tyranny.