Một trong những sự khác biệt lớn giữa quy định của pháp luật tiếng Anh và Continental làm giàu không công bằng dường như là sự biện minh cho khiếu nại bồi thường. Trong khi pháp luật của Đức sáng lập yêu cầu bồi thường về việc thiếu cơ sở pháp lý (Rechtsgrund), Anh tuyên bố trong bồi thường cho phần còn lại trên yếu tố bất công, cụ thể, chẳng hạn như ép buộc, sai lầm hay thất bại của xem xét | 2 Unjust factors and legal grounds Sonja Meier One of the major differences between the English and Continental law of unjust enrichment seems to be the justification for the claim in restitution. Whereas German law founds the claim on the lack of a legal ground Rechtsgrund English claims in restitution are said to rest on a specific unjust factor such as mistake compulsion or failure of consideration. This chapter concentrates on the role of unjust factors and legal grounds in a specific area of unjust enrichment namely where the claimant willingly conferred a benefit - in particular money - on the defendant. It does not deal with cases of encroachment payment of another s debt improvement of another s property or restitution for wrongs. I. Restitution for mistake and the condictio indebiti 1. Liability mistake and condictio indebiti The Roman unjustified enrichment claim that attracts the greatest interest today is the condictio indebiti. It required that the claimant conferred a benefit on the defendant in order to discharge a liability that however did not exist. The action did not lie when the claimant knew that the liability did not exist. Whether there was also a requirement that the claimant had to be mistaken is It may be that in classical law a mistake by the claimant was presumed if he performed in terms of a non-existent liability and that the defendant had to rebut this presumption by showing that the claimant knew that the liability did not exist. But at least in post-classical law the claimant in order to avail himself of the condictio indebiti had to show that he mistakenly assumed the liability to exist. I would like to thank Niall Whitty for commenting upon an earlier draft of this paper. 1 See R. Zimmermann The Law of Obligations Roman Foundations of the Civilian Tradition paperback edn 1996 849 ff. 37 38 SONJA MEIER With this error requirement there originated the long-lasting dispute as to whether a mistake of law would be .
