The American people, I am convinced, really detest free speech. At the slightest alarm they are ready and eager to put it down.

What I got in Sunday school ... was simply a firm conviction that the Christian faith was full of palpable absurdities, and the Christian God preposterous.... The act of worship, as carried on by Christians, seems to me to be debasing rather than ennobling. It involves groveling before a being who, if he really exists, deserves to be denounced instead of respected.

I believe in only one thing and that thing is human liberty. If ever a man is to achieve anything like dignity, it can happen only if superior men are given absolute freedom to think what they want to think and say what they want to say. I am against any man and any organization which seeks to limit or deny that freedom... [and] the superior man can be sure of freedom only if it is given to all men.

Great artists are modest almost as seldom as they are faithful to their wives.

The learned are seldom pretty fellows, and in many cases their appearance tends to discourage a love of study in the young.

Metaphysics is almost always an attempt to prove the incredible by an appeal to the unintelligible.

The only way to reconcile science and religion is to set up something which is not science and something that is not religion.