The most dangerous physicians are those born actors who imitate born physicians with a perfectly deceptive guile.

Do ask yourself why you, the individual, exist, and if you can get no other answer try for once to justify the meaning of your existence as it were a posteriori by setting before yourself an aim, a goal, a 'to this end', an exalted and noble 'to this end'.

There is such a thing as a hatred of lies and dissimulation, which is the outcome of a delicate sense of humor; there is also the selfsame hatred but as the result of cowardice, in so far as falsehood is forbidden by Divine law. Too cowardly to lie.

I consist of body and soul - in the worlds of a child. And why shouldn't we speak like children? But the enlightened, the knowledgealbe would say: I am body through and through, nothing more; and the soul is just a word for something on the body.

Go through the towns and ask yourselves whether these people should reproduce! Let them go to their whores!

For the purpose of knowledge we must know how to make use of the inward current which draws us towards a thing, and also of the current which after a time draws us away from it.

Whoever writes in blood and aphorisms wants not to be learned but to be learned by heart.