Question: In The Wealth of Nations, Adam Smith wrote, "Every individual endeavors to employ his capital so that its produce may be of greatest value. He generally neither intends to promote the public interest, nor knows how much he is promoting it. He intends only his own security, only his own gain. And he is led by an invisible hand to promote an end which was no part of his intention. By pursuing his own interest he frequently promotes that of society more effectively than when he really intends to promote it." How does the story of long-run equilibrium in a perfectly competitive industry illustrate Adam Smith's invisible hand?