Mathematics is the queen of disciplines.... it will drive the nonsense out of your head!

We call beauty that which supplies us with a particular pleasure.

Pierre was right when he said that one must believe in the possibility of happiness in order to be happy, and I now believe in it. Let the dead bury the dead, but while I'm alive, I must live and be happy.

Regard the society of women as a necessary unpleasantness of social life, and avoid it as much as possible.

It is a rude feeling, because it is natural only to people standing on the lowest level of morality, and expecting from other nations such outrages as they themselves are ready to inflict.

The difference between real material poison and intellectual poison is that most material poison is disgusting to the taste, but intellectual poison, which takes the form of cheap newspapers or bad books, can unfortunately sometimes be attractive.

Just as a painter needs light in order to put the finishing touches to his picture, so I need an inner light, which I feel I never have enough of in the autumn.