… is from page 154 of Sir Dennis Robertson ’s important 1954 lecture delivered at Columbia University “What Does the Economist Economize?”, as this lecture appears in his 1956 collection, Economic Commentaries  (original emphasis):
What does the economist economize? ’Tis love, ’tis love,’ said the Duchess, ‘that makes the world go round.’ ‘Somebody said,’ whispered Alice, ‘that it’s done by everybody minding their own business.’ ‘Ah well,’ replied the Duchess, ‘it means much the same thing.’ Not perhaps quite so nearly the same thing as Alice’s contemporaries thought. But if we economists mind our own business, and do that business well, we can, I believe, contribute mightily to the economizing, that is to the full and thrifty utilization, of that scarce resource Love – which we know, just as well as anybody else, to the most precious thing in the world.
DBx: Freedom of exchange and production within a regime of private property rights and freedom of contract harnesses self-interest to the public good. Admiration and endorsement of free markets is not – contrary to much uninformed commentary – admiration and endorsement of greed or materialism. It is, instead, the reflection of an acceptance of the reality that each person’s capacity to care for others is not unlimited.
Yet free markets work wonders in part because each person’s capacity to do no harm to other people’s persons and property is unlimited. And so when strangers meet to exchange, the law of property and contract (and tort) prompts each person to help the others, for only by helping these strangers can each person help himself or herself.