Four varieties in society: lovers, the ambitious, observers, and fools. The fools are the happiest.

I've met many thinkers and many cats, but the wisdom of cats is infinitely superior.

The search for causes must come after the collection of facts.

To have a true idea of man or of life, one must have stood himself on the brink of suicide, or on the door-sill of insanity, at least once.

We study ourselves three weeks, we love each other three months, we squabble three years, we tolerate each other thirty years, and then the children start all over again.

The production of a work of art is determined by the material and intellectual climate in which a man lives and dies.

History is nothing but a problem of mechanics applied to psychology.