A man's interest in the world is only the overflow of his interest in himself

A man's interest in the world is only the overflow from his interest in himself. When you are a child your vessel is not yet full; so you care for nothing but your own affairs. When you grow up, your vessel overflows. . .

By self-interest, Man has become gregarious, but in instinct he has remained to a great extent solitary; hence the need of religion and morality to reinforce self-interest

No man who is occupied in doing a very difficult thing, and doing it very well, ever loses his self-respect

Self-interest is the enemy of all true affection.

We have always known that heedless self-interest was bad morals; we now know that it is bad economics.