激勵相容的法教義學：基於後果預判的目的論證理論

法律本質上是一種激勵機制，“激勵相容”因此應成為疑難案件正當性證成的評判標準。由於法官決策或者影響靜態博弈中雙方當事人是否達成相互合作的納什均衡，或者與潛在當事人未來的行動決策之間存在一種行動順序有先後的動態博弈，法官應在疑難案件的司法推理和法律論證過程中引入博弈分析思路。不僅根據不同裁判規則下潛在當事人的理性選擇，更根據規則下他們之間的策略互動模式及其納什均衡結果來說明或預判社會後果。繼而以立法已然確立的法目的作為論證前提和評價標準，考察比較裁判規則引發的社會後果是否與預期法目的“激勵相容”，並據此選擇一個兼具合法性和合理性的具體裁判方案。基於此，不管是目的解釋、(內部)體系解釋還是法律續造，均需要法官運用博弈分析方法預判兼具一般性和系統性的社會後果，然後在此基礎上根據後果是否與目的兼容的“激勵相容”標準進行實質性的法目的論證。

Law is essentially an incentive mechanism; therefore,“incentive compatibility”should serve as the criterion for justifying the legitimacy of hard cases. Since judicial decisions either affect whether the parties in a static game reach a mutually cooperative Nash equilibrium, or involve a dynamic game with a sequential order of actions between the judge and potential litigants regarding their future conduct, judges should incorporate game-theoretic reasoning into their legal reasoning and argumentation in hard cases. Accordingly, the social consequences should be explained or anticipated not only based on the rational choices of potential litigants under different adjudicative rules, but also based on the patterns of strategic interaction among them under those rules and the resulting Nash equilibrium. Then, taking the legislatively established legal purposes (which embody the legislator's value judgments) as the argumentative premise and evaluative criterion, judges should examine and compare whether the social consequences triggered by alternative adjudicative rules are“incentive-compatible”with the intended legal purposes, and thereby select a specific adjudicative solution that possesses both legitimacy and rationality.