Abstract

The common law's approach in the law of unjust enrichment is to enumerate specific «unjust factors» as permissible causes of action in claims for restitution. This approach has come under attack, inter alia, for being unnecessarily complicated. The claim is that the civilian approach, with its single ground of absence of legal cause for the transfer, is preferable since the operative unjust factor in any particular case is irrelevant to the restitutionary response. In defence of the common law's approach, this article tenders four aspects of the restitutionary response which, it is claimed, are illuminated by reference to the nature, context, and effect of the operative unjust factor in any particular case. They are: (i) the availability of the defence of change of position; (ii) the justifiability of certain «bars» on rescission and the permissible mode of mutual restitution on rescission; (iii) the appropriate measure of enrichment where restitution is, or must be, effected in money; and (iv) two possible justifications for the controversial remedy of partial rescission