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

To know that the Bible is the literature of a barbarous people, to know that it is uninspired, to be certain that the supernatural does not and cannot exist - all this is but the beginning of wisdom.

If a man would follow, today, the teachings of the Old Testament, he would be a criminal. If he would follow strictly the teachings of the New, he would be insane.

Many people think they have religion when they are troubled with dyspepsia.

Every library is an arsenal.

If the Bible and my brain are both the work of the same infinite God, whose fault is it that the book and my brain do not agree?

By physical liberty I mean the right to do anything which does not interfere with the happiness of another. By intellectual liberty I mean the right to think and the right to think wrong.