Whenever a man believes that he has the exact truth from God, there is in that man no spirit of compromise. He has not the modesty born of the imperfections of human nature; he has the arrogance of theological certainty and the tyranny born of ignorant assurance. Believing himself to be the slave of God, he imitates his master, and of all tyrants the worst is a slave in power.

Laughing has always been considered by theologians as a crime.

To avoid pain we must know the conditions of health. For the accomplishment of this end we must rely upon investigation instead of faith, upon labor in place of prayer. Most misery is produced by ignorance. Passions sow the seeds of pain.

There can be but little liberty on earth while men worship a tyrant in heaven.

A believer is a bird in a cage, a freethinker is an eagle parting the clouds with tireless wing.

I do not see how it is possible for an intelligent human being to conclude that the Song of Solomon is the work of God, and that the tragedy of Lear was the work of an uninspired man.

If the account given in Genesis is really true, ought we not, after all, to thank this serpent? He was the first schoolmaster, the first advocate of learning, the first enemy of ignorance, the first to whisper in human ears the sacred word liberty, the creator of ambition, the author of modesty, of inquiry, of doubt, of investigation, of progress and of civilization.