If the people were a little more ignorant, astrology would flourish - if a little more enlightened, religion would perish.

Let us account for all we see by the facts we know. If there are things for which we cannot account, let us wait for light. To account for anything by supernatural agencies is, in fact to say that we do not know. Theology is not what we know about God, but what we do not know about Nature.

All the professors in all the religious colleges in this country rolled into one, would not equal Charles Darwin.

Do not tell me that you have got to be rich! We have a false standard of greatness in the United States. We think here that a man must be great, that he must be notorious; that he must be extremely wealthy, or that his name must be upon the putrid lips of rumor. It is all a mistake. It is not necessary to be rich or to be great, or to be powerful, to be happy. The happy man is the successful man. Happiness is the legal tender of the soul.Joy is wealth.

He who dishonors himself [by lying about his opinions] for the sake of being honored by others will find that two mistakes have been made - one by himself, and the other, by the people.

Liberty is the breath of progress.

I would rather be a beggar and spend my money like a king, than be a king and spend money like a beggar.