"Jena came twenty years after the death of Frederick the Great; the crash will come twenty years after my departure if things go on like this."

"Only a fool learns from his own mistakes. The wise man learns from the mistakes of others."

"The people are like children, they must be led by the hand."

"I have always found that the word 'state' is a very convenient one, as it can mean anything you want it to mean."

"The noise of the world is too loud for me. I need silence to work."