To believe is to know you believe, and to know you believe is not to believe.

Do not fear to be eccentric in opinion, for every opinion now accepted was once eccentric.

Read, every day, something no one else is reading. Think, every day, something no one else is thinking. Do, every day, something no one else would be silly enough to do. It is bad for the mind to be always part of unanimity.

There are two motives for reading a book: one, that you enjoy it; the other, that you can boast about it.

Art is science made clear.

If people never did silly things, nothing intelligent would ever get done.

Live to learn... forget... and learn again.

The greatest challenge to any thinker is stating the problem in a way that will allow a solution.

The one serious conviction that a man should have is that nothing is to be taken too seriously.

The most savage controversies are those about matters as to which there is no good evidence either way.