As quoted in Principles of Economics (Mankiw), from Adam Smith’s The Wealth of Nations (1776): “Man has almost constant occasion for the help of his brethren, and it is in vain for him to expect it from their benevolence only. He will be more likely to prevail if he can interest their self-love in his favor, and show them that it is for their own advantage to do for him what he requires of them. … Give me that which I want, and you shall have this which you want, is the meaning of every such offer; and it is in this manner that we obtain from one another the far greater part of those good offices which we stand in need of.
It is not from the benevolence of the butcher, the brewer, or the baker that we expect our dinner, but from their regard to their own interest. e address ourselves, not to their humanity but to their self-love, and never talk to them of our own necessities but of their advantages. Nobody but a beggar chooses to depend chiefly upon the benevolence of his fellow-citizens. …
Every individual … neither intends to promote the public interest, nor knows how much he is promoting it. … He intends only his own gain, and he is in this, as in many other cases, led by an invisible hand to promote an end which was no part of his intention.Nor is it always the worse for the society that it was no part of it. By pursuing his own interest he frequently promotes that of the society more effectually than when he really intends to promote it.”