“是而然”与“是而不然”:形式、有效性及抵牾

Shi Er Ran and Shi Er Bu Ran:Form,Effective and Conflict

"是而然"、"是而不然"是《小取》研究推论时提出的两种重要情况。这两种情况都可从语法形式及逻辑形式两个层面加以分析。可以证明,"是而然"的逻辑形式是有效的,故"是而然"是有效的演绎推理。"是而不然"诸例看似与"是而然"相矛盾,其实深入分析就可发现,诸例并不构成"是而然"模式反例,因此,"是而不然"的存在实际上不影响"是而然"式推论有效。

The Chapter of Xiao qu in Mo Jing propose two key conceptualizations for the study of inference-＂ Shi Er Ran＂ and＂Shi Er Bu Ran＂. The two conceptualizations can be studied in two levels：the grammatical form and the logical form. It can be proved that the logical forms of＂ Shi Er Ran＂ are valid and thus ＂Shi Er Ran＂ is valid inference. The examples of ＂Shi Er Bu Ran＂ seem to be in contradiction with ＂Shi Er Ran＂. However, we can find through a through analysis that these are not the true counter -examples of ＂Shi Er Ran＂. Therefore, the existence of ＂Shi Er Bu Ran＂ does not affect the validity of the inference＂Shi Er Ran＂.