The Nature of Responsibility for Gain

This chapter examines the normative foundations of private law liabilities for gain (sometimes referred to as unjust enrichment liabilities) from the point of view of a series of basic questions about responsibility. The two basic questions addressed are firstly, how, and in response to what conceptions of responsibility do such liabilities arise; and secondly, what are the implications of this for our understanding of the shape and content of unjust enrichment law? The principle thesis of the chapter is that all legal responsibilities for gain require a relationship between the gain made by the defendant and some harm that the plaintiff has suffered, harm being implicated in the liability in one of three identifiably distinct ways. This conclusion is basically satisfying to the law’s liberal underpinnings, but it also raises an important analytical question which goes to the heart of much modern discourse about unjust enrichment law and which threatens to lift the lid on Pandora’s box: if all liabilities for gain are premised upon some harm the plaintiff has suffered, why do we need a distinct category of unjust enrichment law at all? Why cannot the liabilities at stake be conceptualized more appropriately within our existing private law categories, focusing as these do upon losses a plaintiff has suffered? After a detailed exploration of the various forms of responsibility at play in unjust enrichment cases, the chapter concludes that there are several reasons why this is unlikely to be helpful on both pragmatic and principled grounds. It also sets out five key implications which the analysis has for our understanding of unjust enrichment law, one of which is that cases of unjust enrichment ‘by subtraction’ and unjust enrichment ‘by wrongdoing’, though analytically distinct, may have more normatively in common than writers have hitherto ventured to suggest.