Presumably this is a different Peter Birks from the one who argued in 1985 that certain types of enrichment may be identified from the fact that no reasonable man would deny that they are enrichments (Introduction to Restitution, p116). Of course, Peter may mean merely that not every proposition starting with the words "It is obvious that ..." is true. But I am surprised that he cannot find a politer way to say it.

3. Isaac Newton.
Peter also suggests that

It is both puzzling and disheartening that a senior member of Newton's university should rely, militantly, on an argument of this kind.

I am unfamiliar with Isaac Newton's views on the law of unjust enrichment, and know of no reason to suppose that he would have supported Peter over me. And writing as one who has actually studied physics at university level, I regard it as obvious (that word again) that physics has different objects and different methods from those used by lawyers.

SERIOUS ISSUES : THE EFFECT OF SETTING ASIDE A JUDGMENT
It is pleasing to see various differing views expressed on this, from a variety of jurisdictions. Some views are indistinguishable from my own, such as Duncan Sheehan's view that :

it is tantamount to leaving the judgment in force to say that Archer gets to keep the money

That is it in a nutshell. There are not two distinct things, firstly the setting aside of the judgment, and secondly the return of the money. It is all one thing. And someone who didn't already understand that one thing would not be helped by saying that it was concerned with "unjust enrichment".

There are really three main views to the contrary, the first two of which are not necessarily incompatible with one another, or indeed very far from my own.

1. Some point out that a court which queries an earlier judgment may do other things than simply reverse it and order repayment. This is Allan Axelrod's point, and (if I understand it) Arianna Pretto's as well. Certainly yes, and it may be that what will happen in the Archer case is that something different will be ordered (such as a retrial of the issues). This is all absolutely true, but it is a different problem. We were discussing one possible thing that the court might do, and how to characterise that. The problem is not essentially altered by pointing out that there are other things the court can do.

2. Some admit that it is obvious that a complete reversal of the judgment entails return of the money, but say that "unjust enrichment" is a neat label to apply to this. So Allan Axelrod says :

obvious rules tend to be given names--and a name for the rule that a judgment recipient sometimes has to give some of it back--could be called restitution without shocking too many legal minds, and the ground for the restitution might be 'unjust enrichment' again without jarring too many of the profession?

This is of course exactly what we would expect an American to say, precisely because "unjust enrichment" carries so little theoretical baggage in the US. And were I in America, I might agree. But in England, "unjust enrichment" is not understood that way. The term brings in a whole raft of theoretical concepts, and I'm opposing that here because those concepts don't fit. (I'm not convinced as to how well they fit anywhere else either, but I am trying to deal with one issue at a time.)

I'm not clear in my mind how far the Australian cases quoted carry us. Commonwealth v. MacCormack certainly comes awfully close to saying that the recovery is obvious -- and the only legal tag applied is "restitutio in integrum", which is compatible with just about any legal theory you care to name. Varley v Thompson I can't locate -- it isn't in the AUSTLII database. Perhaps someone else can comment ?

3. Some say this is "unjust enrichment", meaning by this that the whole theoretical apparatus of unjust enrichment theory applies. That is where the fun starts, because there are a number of theories floating around.

SERIOUS ISSUES : UNJUST ENRICHMENT
I think it is in danger of being forgotten here that English Law is NOT committed to a theory of "unjust factors". This is simply an academic idea. "Unjust factors" have only ever been referred to in 4 cases (as of Tuesday evening, when I searched the LEXIS database), and there is a very long way to go before they can be said to be an accepted part of the law. (Of course, Jonathon Moore will point out that there is a much wider body of case law which possibly *may* be explained by reference to "unjust factors"; which is true but again does not carry the matter beyond academic opinions. There is a long and inglorious tradition of treating the least judicial reference to "unjust enrichment" as support for the entire Birksian theoretical edifice. But Jonathon will understand that more is required before it is genuinely part of the common law.) So the question of how useful they are is a very topical and important one, and it is a good thing that this has played such a prominent part in this discussion.

It is clear that this discussion has not shown the "unjust factors" in a good light. Even after it has become clear that the matter is controversial, we still have active support for the factor's being :

1. Compulsion (Jonathon Moore)
2. *Illegitimate* compulsion (Andrew Dickinson - a different thing, as is clear from their explanations)
3 Failure of consideration (Matthew Scully)

It is not clear whether the other factors referred to on earlier days are now being given up by their proponents.

I am not sure that James Edelman's "fraud" and Gerhard Dannemann's "restitution for wrongs" would properly be called additional "unjust factors", but they are certainly additional explanations within the framework of theory of which the "unjust factors" form a part.

What is startling is that there seems to be so little constraint on the creation of new or expanded unjust factors. As I have said already, perhaps this is just a freak case. But if the proliferation and overlap of unjust factors illustrated here is in any way typical, then plainly the theory is in trouble.

As Gerhard Dannemann implies, this problem goes away if we adopt the German perspective (and we have had an interesting exchange of views on whether the Canadian law can be said to be adopting a similar perspective). If, then, English law had adopted not merely unjust enrichment, but unjust enrichment on that particular model, then the Archer case would not be a difficult one. As Gerhard makes clear, of course, that would not mean that we would not have other, possibly very serious, problems in its place !

Steve Hedley

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