论弗雷格的“真之收缩”思想

Frege's Thought of Deflationism

弗雷格运用逻辑分析的方法,提出了自己独特的"真"之思想,形成了关于"真"的完整理论。在他看来,"真"不具有实体属性,不存在与客体在存在方式或存在状况的符合与对应,"真"只用来表达断定句形式中的断定力。当"5是素数"这个句子带有断定力时,真也就被表达出来,它与"5是素数是真的"表达了同样的内容。另外,他将"真"作为初始概念,认为真是不可定义的。如果对"真"进行定义,将走入"定义的循环"。因为要知道什么是"真",就需要论证表象与现实的一致性,而二者的一致又依赖于"真"的定义。这种思路与做法必将导致循环定义,故弗雷格认为"真"是不可定义的。基于以上两点的分析,他再次对符合论提出批评。他认为,如果符合论对"真"的理解是正确的话,那么结论是"事实比真更为基本,应该在事实的基础上定义真",但这显然是错误的,因为我们总是通过真来确定事实,而不是通过事实来确定真。我们似乎可以在弗雷格思想中找到收缩论的雏型,因为他关于"真"的认识与收缩论在很大程度上是一致的。收缩论最重要的观点在于说"P是真的"和说"P"有相同的涵义,谓词"是真的"是多余的。"真"本身是可收缩的,不带有实体性质。于是,我们可把弗雷格作为表达真之收缩观点的第一位哲学家,虽然他并不是坚定的收缩论者。

Frege put forward his own theory of truth using the method of logical analysis. He thought that truth is not a property. There is no real relation between truth and the object. What is truth？ Frege thought that truth is used to express the power of determination. When the sentence ＂5 is a prime number＂ expresses the power of determination, truth will be expressed. So the sentence ＂5 is a prime number＂ has the same meaning with the sentence ＂5 is a prime number＇ is true＂. His second point is that truth is not definable, for in order to know what is truth, we have to argue that appearance coincides with reality. And this depends on the definition of truth. But this will lead to circular definition. So Frege thought that truth is undefinable. Frege criticized the correspondence theory of truth based upon the above two points. He argued that if the correspondence theory of truth is right about truth, then since facts are more basic than truth, we should define truth on the basis of facts. But this is apparently false, for we always determine the facts via truth, but not vice versa. So we could say he was the first philosopher who argued for the deflationism about truth, although what he believed was the weak version of it.