Abstract

The past decade has seen a marked rise in unjust enrichment scepticism across the common-law world. Some argue that the ‘at the expense of ’ element in particular has been over-generalised and that the restitution of unjust enrichment should be principally confined to cases of deliberate conferral by the plaintiff. Others go further and argue that the law of unjust enrichment itself does not exist insofar as ‘unjust enrichment’ is neither a cause of action nor a consideration of justice capable of justifying restitution. This essay offers a tentative response to these arguments, defending a performance-based analysis of core Kelly v Solari-type cases but questioning whether the continued existence of the subject really depends on the tight normative unity that its critics demand. At the same time, the essay considers the ways in which legal history, comparative law and legal theory have acted as drivers of change in this context, examining the phenomenon of change and continuity in private law with reference to these developments.