Every effort under compulsion demands a sacrifice of energy. I never paid such a price.

The progressive development of man [has as its] ultimate purpose the complete mastery of mind over the material world.

Every effort under compulsion demands a sacrifice of energy. I never paid such a price.

A century from now it will no more occur to a normal person to mate with a person eugenically unfit than to marry a habitual criminal.

Love: I recognize the emotion for what it is, an irrational self-destructive impulse, which is disguised as joy.

All the great religions contain wise prescriptions relating to the conduct of life, which hold good now as they did when they were promulgated.

The opinion of the world does not affect me. I have placed as the real values in my life what follows when I am dead.