谈谈词项逻辑的几个问题

Study on Syllogistic Logic

传统词项逻辑预设直言命题主项非空,尽管可以使包括单称命题在内的对当关系全面成立,但是又带来词项逻辑不再具有普适性等诸多问题。因此,现代逻辑学家放弃了存在预设。由于三段论规则仅仅是判定规则,而不是推理规则,那么,被判定为有效的三段论是如何从前提得出结论的?除了运用欧拉图、文恩图和化归方法等外,还可以运用概念(词项)的限制或者概括方法从一个三段论的前提必然地得出结论。

syllogistic logic devdoped by Aristotle has a substantial presumption ,that is ,a categorical proposition has a existential import,its subject has to refer to a non-empty class. But in the view of modem logicians ,the substantial presumption should be to get rid of, because it is beset with difficulties. Moreover, categorical syllogism which is valid could be interpreted with the method of amplification-diminution of term.