Reason is the light, the sun of the brain. It is the compass of the mind, the ever-constant Northern Star, the mountain peak that lifts itself above all clouds.

The few have said, Think! The many have said, Believe! The first doubt was the womb and cradle of progress, and from the first doubt, man has continued to advance.

Honest investigation is utterly impossible within the pale of any church, for the reason, that if you think the church is right you will not investigate, and if you think it wrong, the church will investigate you.

I would not for my life destroy one star of human hope, but I want it so that when a poor woman rocks the cradle and sings a lullaby to the dimpled darling, she will not be compelled to believe that ninety-nine chances in a hundred she is raising kindling wood for hell.

One good schoolmaster is worth a thousand priests.

Only a few years ago there was no person too ignorant to successfully answer Charles Darwin; and the more ignorant he was the more cheerfully he undertook the task.

If I owe Smith ten dollars and God forgives me, that doesn't pay Smith.