Abstract
Case law suggests that the law responds differently to mistaken payments of money than to other mistaken transactions, i.e. the mistaken supply of goods or conferral of services. The Birksian theoretical explanation for this difference is that recipients of money are precluded from denying that they have been enriched while recipients of goods or services are not so precluded. If correct this explanation significantly limits the scope of the Law of Restitution. This article critically examines this argument and advances an alternative theoretical explanation for the results in case law.