弗雷格-计奇难题的混合表达论消解方案论析

The Frege-Geach Problem and Its Hybrid Expressivist Solution

弗雷格-计奇难题关涉如何合理解析复合型道德断言的语义以及如何论证道德假言推理的有效性。传统道德表达论通常主张道德断言仅表达言者态度而不表达命题,而这种一元论立场证明无以破解这一难题。相反,道德混合表达论试图构建一种二元论框架,兼容道德断言既可表达非认知态度又可表达表征性信念的双重特性,为该难题的消解提供了一个全新视角。混合表达论者一方面将道德术语类比作轻蔑语,以确保同一道德谓词在简单或复合断言中均表达相同的道德态度,另一方面通过阐明道德假言推理的深层逻辑结构,论证假言推理的有效性。

The Frege - Geach Problem mainly concerns how to reasonably interpret the semantics of complex moral assertions and how to validate moral inference. The traditional expressivism typically maintains that moral assertions can merely express the speaker＇s attitudes rather than propositions, but it has been proved that such a monist stance fails to crack this problem. In contrast, the hybrid expressivism provides a new perspective for resolving the puz- zle by endeavoring to construct a dualist framework which can accommodate the duality of moral assertions in expressing both non - cognitive attitudes and representative beliefs. Hybridists, on the one hand, analogize moral terms as slurs so as to ensure that the same moral predicate expresses fixed moral attitudes in both atomic and compound assertions. On the other hand, they successfully validate moral inferences in virtue of explicating the deep logical structures of moral reasoning.