What Renders Enrichment Unjust

I. An Ancient Idea of Justice John Dawson saw better than most the idea of justice that is at the heart of much of the law of Restitution. He thought the idea was best expressed by the ancient Roman maxim: "For this by nature is equitable, that no one be made richer through another's loss."' In the common law, this idea of justice has been obscured by a jumble of doctrine. "Our working method is to search out some such ground," Dawson observed, referring to the traditional grounds for restitution, "if we cannot rest the award of restitution on one of them we are usually at a loss."2 Dawson thought it best to leave the idea obscure. Once made explicit, he warned, the idea "has the peculiar faculty of inducing quite sober citizens to jump right off the dock."3 He ascribed the idea's power to its "strong appeal to the sense of equal justice [combined with] the delusive appearance of mathematical simplicity."4 Dawson believed that the idea did not have to be made explicit to do justice by it in any event. Late in his life he wrote, "This highly volatile idea has the propensity . . . to filter through barriers. One must expect to find leaks in the barriers even when their foundations seem firm."5 Dawson's worry was that, if made an explicit principle of law, this idea of justice would unsettle people's power to control their affairs through contract and gift. In his memorable metaphor, Dawson warns that the idea leads us into a forest of enchantment' where every disposition of wealth would be open to review with "inquiries into the effects of legal transactions not only on the immediate parties but on third persons and persons still further removed."' Dawson said little about the reasons for staying on the law's time-worn narrow paths through this forest, perhaps because he thought the reasons self-evident. The narrow course reduces litigation, promotes finality and certainty, and encourages self-reliance. Dawson's book, written over a half century ago, remains timely. His target was the Restatement of Restitution, published in 1937, which embraced the general principle that he feared might lead us astray. Dawson's fears have not been realized in the United States. Since Dawson wrote, Restitutions disappeared as a subject in American law schools, as did academic interest in private-law doctrine.9 But the Restatement has had an impact in England, from whence its message is now being transmitted to the common-law world." Whether and how we should recognize unjust enrichment as a heading of obligation are very much live issues today. Dawson also reminds us of a lost perspective on the law that we must regain if we are to make headway in understanding private law on its own terms. The modern fashion is to look to economics or to moral philosophy to explain the law, as if techniques for unraveling the law's subtleties could be found in the more pristine principles and rigorous techniques of these other disciplines. Legal "conceptualists," or formalists, are fighting back, but they risk falling into the old trap of believing that parsing the concepts of the law can resolve what are at bottom hard questions of morality and policy. Dawson's work challenges reductionism of either the philosophical or legal stripe. He teaches us to be skeptical about legal formulae. It was Dawson who warned about "that well-known ailment of lawyers, a hardening of the categories."" But he also teaches us to be respectful of traditional formulae, and to be mindful of the possibility that behind them may lie something in human conscience-Dawson called it "a sense of justice""-that, while ineffable, is real. The law of unjust enrichment is proof against economic reductionism. At its core, this body of law is about reversing accidental shifts of wealth, which is impossible to justify solely in economic terms. Utilitarian concerns are a reason to limit the law's reversal of accidental shifts of wealth; they do not justify it. …