Justifying the Law of Unjust Enrichment

Part of the IDEA research seminar series

Speaker: Duncan Sheehan (Leeds, School of Law)

Justifying unjust enrichment law has become a battleground between two camps of scholars who come at the topic with radically different ideas – either explicitly or implicitly – as to how legal concepts work and interact with each other.

In the first part of the paper, drawing on work done for chapter 1 of my book The Scope and Structure of Unjust Enrichment, I argue that legal concepts are Weberian ideal types. In other words they never exist in pure form in the real world. I suggest that the process of applying legal concepts starts with a recognition that they possess first an abstract, idealised intension – the abstract set of conditions needed for the concept’s operation and a factual extension – the set of facts on the ground to which it applies.

Drawing on Dworkin, I argue that judges in deciding a case should look to whether the suggested solution “fits” well with prior cases and also shows those cases in the best moral light. This dynamic approach of looking forward at the moral justification of the cases and backwards at their “fit” is what leads Dworkin to talk of the law “working itself pure”. It finds a home in the way that Weberian ideal types are always a work-in-progress just like the law generally. Drawing on Wittgenstein, I suggest the way this work is done is by way of family resemblances – family resemblances between the intension and extension and family resemblances between different concepts and the same concept looked at over a period of time. Those family resemblances must be morally and normative significant values underlying the cause of action. I also observe that this seems consistent with the Hegelian view of conceptual development.

In the second part of the paper, drawing on chapter 3, I argue that while the different claims of unjust enrichment law have significant dissimilarities they also have significant normative similarities. I tease out these normative (and actually also analytic) similarities and argue that while unjust enrichment overlaps with other categories (eg property or contract) it has a useful independent existence. One such similarity is the importance of “mistake” and so I defend it briefly against the Kantian argument that to rest a claim on the claimant’s mistake is to use the defendant (illegitimately) as a means to the claimant’s ends. 

All welcome. Join in person in Seminar Room 2, IDEA, 17 Blenheim Terrace, or email Andrew Kirton for a Teams link.