There are, first of all, two kinds of authors: those who write for the subject's sake, and those who write for writing's sake. ... The truth is that when an author begins to write for the sake of covering paper, he is cheating the reader; because he writes under the pretext that he has something to say.

A man of business will often deceive you without the slightest scruple, but he will absolutely refuse to commit a theft.

Patriotism, when it wants to make itself felt in the domain of learning, is a dirty fellow who should be thrown out of doors.

What a man is contributes much more to his happiness than what he has or how he is regarded by others.

Reason deserves to be called a prophet; for in showing us the consequence and effect of our actions in the present, does it not tell us what the future will be?

If anyone spends almost the whole day in reading...he gradually loses the capacity for thinking...This is the case with many learned persons; they have read themselves stupid

Mensch kann tun was er will; er kann aber nicht wollen was er will. (One can choose what to do, but not what to want.)