比例原則還是成本收益分析

比例原則是公法學說和實踐中常見的審查立法和政府行為合理性的方法。近年來，有學者主張將比例原則推廣至更為廣泛的領域，使之成為“法律帝國基本原則”。但與經濟學中的成本收益分析方法相比，比例原則無法全面關照決策者應考慮的各種成本、收益因素，至多構成殘缺的成本收益分析，而其機械的四步分析法很容易誤導法律人的理性思維。對德國權威學者阿列克西的比例原則理論進行批判性分析，則可揭示出比例原則在學理上存在更深刻的謬誤。因此，即使比例原則可用於限制法院審查立法或行政舉措時的裁量權，在立法政策選擇、行政舉措權衡以及法院處理民事糾紛等語境中，比例原則也不應被廣泛適用，而經濟學的成本收益分析才是更適當的理性思維和決策方法。

The Proportionality Principle is widely used in reviewing theconstitutionality of public law in many countries, so much so that in China many scholars have championed the use of the Proportionality Principle in private law. Nonetheless, is the Proportionality Principle really a serviceable tool in decision-making? Using economic analysis of law, this article argues that while the Proportionality Principle can be used to limit the reviewing power by courts, in other contexts, such as legislative or administrative policy-making and courts’ resolving private disputes, the Proportionality Principle is inferior to the cost-benefit analysis, as the latter takes into account relevant costs and benefits more comprehensively. Relying on the Proportionality Principle will often lead to adopting erroneous policies. In addition to criticizing the supporting arguments for the Proportionality Principle found in the top law journals, this article also demonstrates why even Robert Alexy’s theorizing attempts cannot save the Proportionality Principle. The suitability test as nothing but Pareto optimality leads to absurd results: either no law can pass this test or all laws can. The weight formula accounts for two competing principles but may not be useful where it is two alternative policy measures that are to be compared with each other.