Be robbers and ravagers as long as you cannot be rulers and owners, you men of knowledge! The time will soon be past when you could be content to live concealed in the woods like timid deer!

However far man may extend himself with his knowledge, however objective he may appear to himself - ultimately he reaps nothing but his own biography.

There is a stupid humility that is quite common and when a person is afflicted with it, he is once and for all disqualified for being a disciple of knowledge.

Every acquisition, every step forward in knowledge is the result of courage, of severity toward oneself, of cleanliness with respect to oneself.

We have no organ at all for knowledge, for truth: we know (or believe or imagine) precisely as much as may be useful in the interest of the human herd, the species: and even what is here called usefulness is in the end only a belief, something imagined and perhaps precisely that most fatal piece of stupidity by which we shall one day perish.

Partial knowledge is more triumphant than complete knowledge; it takes things to be simpler than they are, and so makes its theory more popular and convincing.