Laughter means: taking a mischievous delight in someone else's uneasiness, but with a good conscience.

It is not to everyone's taste that truth should be pronounced pleasant. But at least let no one believe that error becomes truth when it is pronounced unpleasant.

We should not talk about our friends: otherwise we will talk away the feeling of friendship.

The belief in authority is the source of conscience; which is therefore not the voice of God in the heart of man, but the voice of some men in man.

An educator never says what he himself thinks, but only that which he thinks it is good for those whom he is educating to hear.

I can tell by my own reaction to it that this book is harmful." But let him only wait and perhaps one day he will admit to himself that this same book has done him a great service by bringing out the hidden sickness of his heart and making it visible.— Altered opinions do not alter a man’s character (or do so very little); but they do illuminate individual aspects of the constellation of his personality which with a different constellation of opinions had hitherto remained dark and unrecognizable.

For what purpose humanity is there should not even concern us: why you are here, that you should ask yourself: and if you have no ready answer, then set for yourself goals, high and noble goals, and perish in pursuit of them!