It was modesty that invented the word "philosopher" in Greece and left the magnificent overweening presumption in calling oneselfwise to the actors of the spirit--the modesty of such monsters of pride and sovereignty as Pythagoras, as Plato.

I fear animals regard man as a creature of their own kind which has in a highly dangerous fashion lost its healthy animal reason - as the mad animal, as the laughing animal, as the weeping animal, as the unhappy animal.

They devour each other and cannot even digest themselves.

Whatever a theologian regards as true must be false: there you have almost a criterion of truth.

We are unknown to ourselves, we men of knowledge - and with good reason. We have never sought ourselves - how could it happen that we should ever find ourselves? It has rightly been said: "Where your treasure is, there will your heart be also"; our treasure is where the beehives of our knowledge are.

The value of a man can only be measured with regard to other men.

Not doubt, certainty is what drives one insane.