可能世界的模态论证

A Modal Argument on the Thesis of Possible World

克里普克的可能世界理论是对其后天必然真理学说的从物论证。该理论的主要内容可归结为"偶然实体(或可能个体)的偶然事实"。本文通过分析其关键性概念"可能世界(或个体)"以及"世界的可能样态",试图指出该论证存在根本性错误:"可能个体(或世界)"是不可能的;经验事实是必然的。客观世界的全部现实性是经验命题的从物必然性依据:凡是现实的,都是必然的;"可能性"或"偶然性"等概念从根本上说是从言模态的表达方式。因此,对一阶谓词逻辑正确的模态刻画不仅包括a=b→□(a=b),同时还包括a→□a以及a→□F(a)。

Kripke’s possible world theory offers a major argument for his a posteriori necessary truth. The key spirit of the theory can be concluded as “contingent facts about contingent entities(with necessary self-identity)”, which may well be rejected as fallacious in this thesis: contingent entities(or possible objects) are impossible and empirical facts are necessary. It is the totality of the actual world that is responsible for the whole de re story;there is not a single element in this world that is unnecessary. The concepts of “possibility” and “contingency” are basically residents of the de dicto territory;hence an improved de re account for the first-order predicate logic: a →□a and a →□F(a).