"Private vice can be publicly beneficial"....That is, a just and beneficial social order could be built on the basis of, not individual virtue, but individual self-interest. Self-interest, even avarice or greed, might lead to public benefits. This was utterly foreign to ancient/medieval thought. If you asked Plato or Aristotle or Aquinas, if we start with a group of individuals whose behaviour is dominated by vices -- namely, they're selfish -- can we design a system which will, without them undergoing a conversion, take their selfishness and together weave out of that a result that's good for all, Plato and Aristotle and Aquinas would have said, "Of course not. Garbage in, garbage out. You start with vice at the basis of your system, you're going to have a vice-ridden system." The modern idea of spontaneous order implies that you can.
And of course, in there are the seeds of capitalism.
- Lawrence Cahoone