Beware the barrenness of a busy life.

Be not ashamed of mistakes 

and thus make them crimes.

The influence of a vital person vitalises … . 

The world without spirit is a wasteland.

An idea, like a ghost, 

must be spoken to a little 

before it will explain itself.

Everyone has the right to doubt everything as often as he pleases 

and the duty to do it at least once. 

No way of looking at things is too sacred to be reconsidered. 

No way of doing things is beyond improvement.

Humour is by far the most significant activity of the human brain.

A man is nothing but breath and shadow.