The fundament upon which all our knowledge and learning rests is the inexplicable.

Man is never happy, but spends his whole life in striving after something which he thinks will make him so.

The first forty years of life give us the text; the next thirty supply the commentary on it.

Boredom is an evil that is not to be estimated lightly. It can come in the end to real despair. The public authority takes precautions against it everywhere, as against other universal calamities.

My body and my will are one.

To desire immortality for the individual is really the same as wanting to perpetuate an error forever.

A man of genius can hardly be sociable, for what dialogues could indeed be so intelligent and entertaining as his own monologues?