Lessons from a 'Conversation' About Restitution

Abstract

In Australia, the law of restitution adheres to the approach exemplified by Lord Mansfield in Moses v Macferlan. It does not recognise ‘unjust enrichment’ as a definitive principle. In the late 20th century, the English courts recognised the principle and, shortly after, the defence of change of position. These developments may owe much to a ‘conversation’ between English and German legal scholars. The German Bürgerliches Gesetzbuch [Civil Code] (‘BGB’) has long recognised the defence, as a counterpoint to its broad ‘absence of basis’ ground for liability. Notably, however, English law has not (yet) embraced such a broad ground for liability, and still requires a vitiating factor, such as mistake, to found a restitutionary claim. This article considers what implications the adherence to the considerations in Moses v Macferlan may have for the acceptance in Australia of the change of position defence as it is known to English and German law.