怎样认识全称命题主项存在问题

How to undersdand the existence of universal proposition's subject

有些逻辑理论认为,一个全称命题是真的,并未断定其主项的对象是存在的,这就给有关直言命题推理带来了困难。为使推理成立,就必须假设全称命题主项的对象是存在的。但本文认为,当谈论全称命题的真假时,其主项对象的存在就已经被设定,因此无须再进行假设。同时要对“存在”作广义的理解,而不能仅仅局限于现实世界的范围之内。这样,不仅能有效地解决直言命题有关推理问题,而且也能有效地利用文恩图来判定推理的有效性。

Some logic theories hold that it would make the reasoning difficult when a universal proposition is true and the existence of its subject抯 object is not confirmed.To make the reasoning tenable, the object of the universal proposition抯 subject should be supposed to be there. This article argues, however, in discussing the true or false of a universal proposition, the existence of the object should be supposed to have been enacted. As a result, there is no need to present another supposition. Furthermore, a correct understanding of the logic meaning of 揺xistence?will not only help prove the validity concerning the reasoning of categorical proposition, but also help make full use of Venn抯 graph to determine the validity of the reasoning.