半掩于救济的债因:美国不当得利法发展简史

The Cause of Obligation Partially- Immersed in Relief:A Brief History of American Law on the Unjust Enrichment

无论是作为殖民地还是作为独立国家,美国早期的不当得利判例大多都以英国诸多不当得利诉讼形式以及作为其理论基础的默示契约理论为根源。与碎片化的判例形成鲜明对照的是,统一的不当得利观念却在法学研究和教育中逐渐萌发,这直接推动了美国第一次返还法重述的公布,普通法和衡平法上众多迥异而复杂的规则因此在不当得利原则之下被整合起来。然而,第一次重述自身的缺陷与社会发展使重述修订成为美国法律协会的重要任务,在历时五年的第二次重述失败后,集大成的第三次重述经过十五年艰苦努力后终于成功完成,其一方面将不当得利返还作为整个返还法的基本原则,使普通法系杂乱的返还法判例得以最大程度地体系化和规范化,另一方面也使传统返还法混乱的逻辑被固化,不仅使返还法与合同法、侵权法、信托法的制度边界继续纠缠不清,而且使返还请求权与不当得利之间的关系更加难以澄清,不当得利仍然是一种半掩的债因。

In earlier America either as a British colony or as an independent country,case laws on unjust enrichment are generally based on British litigations for unjust enrichment and its underlying principle of the implied contract theory. In contrast with the fragmented case laws,a uniform doctrine on unjust enrichment has gradually developed in jurisprudence studies and legal education,which has directly promoted the promulgation of the first Restatement of restitution,integrating different and complex rules in common law and equity law under the doctrine of unjust enrichment. However,in light of the imperfection of the first Statement and social development,the modification of restatement is the primary task for American Bar Association. Upon the failure of the second Restatement after five years,the third Restatement is finally accomplished by strenuous efforts of 15 years. In the third Restatement,on one hand the unjust enrichment is considered as the underlying principle of the whole restitution law thus to the greatest extent systemize and normalize the case law on restitution in common law system; on the other hand,the chaotic logic of traditional restitution law is fixed resulting in a tangled system boundary among the restitution law,contract law,tort law and trust law. Further,the relation between the claims for restitution and unjust enrichment becomes more blurring and thus unjust enrichment is still a partially- immersed cause of obligation.