关于直言三段论规则4及相关问题的探讨

The Study on the Fourth Rule of Categorical Syllogism and Other Relevant Questions

词项逻辑的预设前提——主谓项均为非空非全的类,决定命题的换质变形是普效的。据此当然也可对三段论的前提进行换质。这样就使得三段论规则4不是普效的,应该废除,以保证词项逻辑的体系一致性。

The presupposition of logic of term, the terms （ subject and predicate） are neither null class nor universal class, determines the validity of obversion. In order to maintain the consistency of the logic of term, the fourth rule of categorical syllogism must be abolished, the reason of it is as follows： if obversion is applied to the premises of categorical syllogism, it results in the invalidity of the fourth rule.