Adam Smith said that if everyone pursues their own profit, then the profit of all will be maximized by the invisible hand—that is, by nature—just naturally. Go about pursuing your own profit, and you are helping everyone. This is linked to a general metaphor that views well-being as wealth. For example, if I do you a favor, you say, “I owe you one” or “I’m in your debt.” Doing something good for someone is metaphorically like giving him money. He “owes” you something. And he says, “How can I ever repay you?”
