休谟法则和拯救实践

Hume’s Law and To Save Praxis

休谟法则是哲学史上的一个疑难问题,它不仅抽空了价值判断的理性基础,而且质疑理性对行动的指导作用,从而对人类的理性行动或实践构成严峻挑战。从述谓或判断的分类入手,可以揭示在事实判断和价值判断传统二分的基础上不足以对理性行动进行有效辩护,并提出比较性述谓和归属性述谓的区分来替代传统二分。以"好"为谓词的价值判断固然不能还原为事实判断,但是可以还原为比较性述谓,比较性述谓所蕴含的"知好选好"结构则表明了价值判断的理性特征以及理性和选择的内在统一,由此理性行动得到了更为有效的辩护。从比较性述谓到归属性述谓的转变,在某种意义上意味着不是从"是"推出"应该",而是从"应该"推出"是"。

Hume＇s Law is a difficulty issue in philosophical history, which evacuates the rational ba- sis of value judgment and questions the guiding function of reason to action so as to challenge man＇ s rational action and practice. This article points out that the basis of traditional dichotomy of factu- al judgment and value judgment can not defend for rational action efficiently, and therefore it pro- pounds the distinction between comparative predication and attributive predication to replace the tradi- tional one. Value judgment with ＂good＂ as predicate can not be restored to factual judgment, but it can be restored to comparative predication, whose structure of ＂knowing good and choosing good＂ shows the rational feature of value judgment and the innate unification of reason and choice so that rational action can be defended efficiently. The change from comparative predication to attributive predication does not mean in a sense to get ＂should＂ from ＂be＂, but get ＂be＂ from ＂should＂.