No falsehood is so fatal as that which is made an article of faith.

All national institutions of churches, whether Jewish, Christian or Turkish, appear to me no other than human inventions, set up to terrify and enslave mankind, and monopolize power and profit.

To argue with a man who has renounced his reason is like giving medicine to the dead.

Reason obeys itself; and Ignorance submits to whatever is dictated to it.

A man will pass better through the world with a thousand open errors upon his back than in being detected in one sly falsehood. When one is detected, a thousand are suspected.

Any system of religion that has anything in it that shocks the mind of a child, cannot be true.

A thing moderately good is not so good as it ought to be. Moderation in temper is always a virtue; but moderation in principle is always a vice.

Always do right. It will please some people and astonish the rest.

By failing to prepare you are preparing to fail.

When you’re finished changing, you’re finished.

Glass, china, and reputation are easily cracked, and never mended well.

I never knew a man who was good at making excuses who was good at anything else.