The pleasures of the imagination are as it were only drawings and models which are played with by poor people who cannot afford the real thing.

Nothing puts a greater obstacle in the way of the progress of knowledge than thinking that one knows what one does not yet know.

Here take back the stuff that I am, nature, knead it back into the dough of being, make of me a bush, a cloud, whatever you will, even a man, only no longer make me.

What is called an acute knowledge of human nature is mostly nothing but the observer's own weaknesses reflected back from others.

Theologians always try to turn the Bible into a book without common sense.

Just as we outgrow a pair of trousers, we outgrow acquaintances, libraries, principles, etc., at times before they're worn out and times - and this is the worst of all - before we have new ones.

Some people feel with their heads and think with their hearts.