The limitations of unjust enrichment : a new perspective on restitution

Abstract

This thesis is about attempts to provide a theoretical framework for the law of Restitution, a subject in which there is growing academic and judicial interest. Part I of the thesis considers the concept of "unjust enrichment", which is currently gaining the status of orthodoxy as an explanation of Restitution. The law of Restitution, perceived to be a third category, alongside contract and tort, of the law of obligations, is said to consist of liability rules uniformly explicable as having a purpose of the reversal of unjustly obtained or retained enrichment. As a brief historical survey of Restitution demonstrates, unjust enrichment theory is an a-historical attempt to unify and explain a very diverse range of topics. Part I goes on to consider what unjust enrichment means, specifically by considering the content given to the two most important parts of that concept: "unjustness", and "enrichment" or "benefit". A range of views as to the meaning of both parts are considered. None of these views or approaches, however, satisfactorily allows us to explain liability in many cases. Many cases said to be explicable on the basis of the reversal of unjust enrichment are not in fact so concerned. It is concluded that the concept of unjust enrichment is not useful as an explanation of much of the law of Restitution. In Part II of this thesis, the writer consequently seeks alternative ways of conceptualising Restitution. Rather than conceive of that subject as explicable in terms of one, unifying principle, the writer instead identifies four distinct categories of cases. Each category addresses very different types of problems, and is explicable in terms of distinct ideas. In the first category of cases, (Chapter 6) liability is imposed because of particular conduct of a defendant, where a plaintiff has relied on such conduct to his or her detriment. Liability is imposed on a defendant at least to return the plaintiff to his or her previous position before the offending conduct, and irrespective of whether the defendant has obtained any benefit. In the second category of cases (Chapter 7) liability may arise because parties share a common interest in a matter, which matter is affected by an unprovided for contingency. In such cases, the parties community of interest in the matter justifies the operation of a principle of "just sharing", which principle requires the parties to share gains and losses arising as a result of the contingency, according to their relative contributions to the matter in which they have the common interest. In the third category of cases (Chapter 8) liability may arise where a plaintiff has justifiably intervened in another's affairs, and seeks to recover the costs of such intervention from that other. Social policy concerns appear to be the most important factor in determining in which circumstances such recovery will ensue. In the fourth category of cases (Chapter 9) recovery is sought from an innocent defendant who have received something (money, goods or services) from a plaintiff. The plaintiff will be entitled to recover the money or goods, or obtain some form of remedial relief for the services conferred, where such remedial relief or recovery in no way leaves the innocent defendant at a disadvantage.