Jealousy, that dragon which slays love under the pretence of keeping it alive.

To live remains an art which everyone must learn, and which no one can teach.

One can know nothing of giving aught that is worthy to give unless one also knows how to take.

There is a very intimate connection between hypnotic phenomena and religion.

Every ist writes his own autobiography.

There is nothing more fragile than civilization.

All civilization has from time to time become a thin crust over a volcano of revolution.