不當得利法的希爾伯特問題

《民法典》首次系統規定不當得利法，尋求妥當的解釋論成為當務之急。不當得利法體系龐雜，議題繁多。其基本問題包括：［1］不當得利與其他責任的關係；［2］不當得利類型論應遵循統一說抑或非統一說；［3］何謂“沒有法律根據”；［4］因果關係作為不當得利構成要件的意義；［5］獲利應否返還；［6］強迫得利該如何判定和評價；［7］如何理解為履行道德義務進行的給付；［8］如何理解明知無給付義務而進行的債務清償；［9］得利人的善意或惡意在不當得利法上的意義。破除對德國不當得利理論體系的迷信和盲從，立足我國實證法並結合比較法最新發展趨勢對這些基本問題深入分析，將對不當得利法本土解釋論的建構起到引領性的奠基作用。

The PRC Civil Code, for the first time, systematically provides for the law of unjust en-richment. The basic matters include: the relationship between unjust enrichment and other liabilities; the theory of types of unjust enrichment should follow either a unified or non-unified doctrine; the meaning 'without legal ground'; the significance of causation as a constituent element of unjust en-richment; 5 whether profits should be returned; 6 how to determine and evaluate imposed enrichment; how to understand a payment made in fulfillment of a moral obligation; 8 how to understand the set-tlement of debt that knowing there is no duty of performance; 9 the significance of the good faith and bad faith of the benefited people in the law of unjust enrichment. Analysis of these fundamental issues will play a leading and foundational role in constructing a local interpretation of unjust enrichment law in China.