Fathers have a lot to do to make up for having sons.

In order to acquire intellect one must need it. One loses it when it is no longer necessary.

The higher its type, the more rarely a thing succeeds.

Your god is dead and only the ignorant weep. And if you claim there is a hell, then we shall meet there!

In intercourse with scholars and artists one readily makes mistakes of opposite kinds: in a remarkable scholar one not infrequently finds a mediocre man; and often, even in a mediocre artist, one finds a very remarkable man.

Women are quite able to make friends with a man; but to preserve such a friendship - that no doubt requires the assistance of a slight physical antipathy

Science ... has no consideration for ultimate purposes, any more than Nature has, but just as the latter occasionally achieves things of the greatest suitableness without intending to do so, so also true science, as the imitator of nature in ideas, will occasionally and in many ways further the usefulness and welfare of man,-but also without intending to do so.