Fear paints pictures of ghosts and hangs them in the gallery of ignorance.

We have at last ascertained that miracles can be perfectly understood; that there is nothing mysterious about them; that they are simply transparent falsehoods.

Intellectual liberty [is] the right to think right and the right to think wrong. Thought is the means by which we endeavor to arrive at truth.

Years should not be devoted to the acquisition of dead languages or to the study of history which, for the most part, is a detailed account of things that never occurred. It is useless to fill the individual with dates of great battles, with the births and deaths of kings. They should be taught the philosophy of history, the growth of nations, of philosophies, theories, and, above all, of the sciences.

I would rather smoke one cigar than hear two sermons.

Our hope of immortality does not come from any religions, but nearly all religions come from that hope.

The true civilization is where every man gives to every other every right that he claims for himself.