性质命题推理有效性的欧拉图解法判定

The Use of Euler Diagram in Characteristic Proposition Reasoning Validity Decision

凡性质命题推理有效式,就是在欧拉图解中证明为前提真结论必然真的推理形式;凡性质命题推理无效式,就是在欧拉图解中证明为前提真结论并非必然真的推理形式。运用欧拉图解法要掌握三个要点:准确画图、准确识图和准确判定。判定三段论的有效性,要能根据假定前提为真时的大、小前提命题形式的欧拉图,准确无误地画出S、P、M三者外延关系的欧拉图。判定性质命题变形推理的有效性,必须把S、P两个主、谓项的欧拉图,改造成S、P、(?)、(?)四个主、谓项的欧拉图,并能准确识别四种性质命题形式欧拉图中S与P、S与(?)、(?)与P、(?)与(?)这四种外延关系分图。

The characteristic proposition reasoning validity form can be understood as a kind of reasoning form, which can be testified, in Euler diagram, as definitely ＂true＂ verdict under a premise. The characteristic proposition reasoning invalidity as a form can be testified as not ＂true＂. With a nice drawing, correct charting and right decision, the Euler diagram can be applied well. To determine the validity of a syllogism, on the basis of the Euler diagram when in the form of major or minor premise which is true, we can correctly draw the Euler diagram which can tell the relationship among the respective notion of S, P, and M. To determine the validity of a transformed reasoning, we should alter the Euler diagram about subject ＂S＂ and predicate ＂P＂ to the one about subject ＂S＂ , subject ＂S＇and predicate ＂P＂ and predicate ＂P＇, and distinguish the respective drawing which shows the relationship of the pairs with different notion among S＆P, S ＆ P, S＆P.and S＆P.