  Adam Smith’s argument for the invisible hand that keeps sellers competitive rather than in collusion is a fundamentally important and benign—indeed, beneficial—instance of the logic of collective action. He says that each producer “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 [the individual’s intended end]. By pursuing his own interest he frequently promotes that of society more effectually than when he really intends to promote it” (Smith [1776] 1976, bk. 4, chap. 2, p. 456). The back of the invisible hand swats down efforts at price collusion, thereby pushing producers to be innovative.