In 1832 William Forster Lloyd, a political economist at Oxford University, looking at the recurring devastation of common (i.e., not privately owned) pastures in England, asked: “Why are the cattle on a common so puny and stunted? Why is the common itself so bare-worn, and cropped so differently from the adjoining inclosures?”

Lloyd’s answer assumed that each human exploiter of the common was guided by self-interest. At the point when the carrying capacity of the commons was fully reached, a herdsman might ask himself, “Should I add another animal to my herd?” Because the herdsman owned his animals, the gain of so doing would come solely to him. But the loss incurred by overloading the pasture would be “commonized” among all the herdsmen. Because the privatized gain would exceed his share of the commonized loss, a self-seeking herdsman would add another animal to his herd. And another. And reasoning in the same way, so would all the other herdsmen. Ultimately, the common property would be ruined.

Even when herdsmen understand the long-run consequences of their actions, they generally are powerless to prevent such damage without some coercive means of controlling the actions of each individual. Idealists may appeal to individuals caught in such a system, asking them to let the long-term effects govern their actions. But each individual must first survive in the short run. If all decision makers were unselfish and idealistic calculators, a distribution governed by the rule “to each according to his needs” might work. But such is not our world.