索伦森“使真者—间隙认知主义”及其困境

Criticism on Sorensen’s Truthmaker-Gap Epistemicism

作为认知主义者的索伦森不同于威廉姆森,他不用“无知”来解释模糊性。他宣称,模糊性是由语义特征“使真者间隙(Truthmaker Gap)”引起的,并且这一特征使“无知”成为一个必然的附带结果。他强调,我们能够找到模糊谓词F的一个精确分界点n,使得形如Fa n→Fa n+1的命题的前件为真且后件为假;但由于使真者间隙,这些命题既无使真者又无使假者,它们如同一座“认知孤岛”,人们无法获得通达其真值的认知渠道,因而这些命题是形而上学不可知的。索伦森的使真者间隙认知主义能够保证所有包含模糊谓词的命题在经典逻辑内有效,也能够解释绝对边界情形存在但不可知的原因。然而,这一理论也面临着如“认知孤岛并非真正的孤岛”和“与高阶模糊性不相容”等问题。

As an Epistemicist,Roy Sorensen differs from Timothy Williamson that he rejects to use“ignorance”to explain vagueness.Sorensen prefers an account in which vagueness arises from a semantic feature“truthmaker gap”which precipitates ignorance as a necessary byproduct.He claims that there is a cut-off point n,such that for all propositions which have the form“Fan(Fan+1”,the antecedent is true and the seccedent is false.Since all this kind of propositions are truthmaker gap,they have neither a truthmaker nor a falsemaker,and they are“epistemic island”so that there is absolutely no epistemic access to them.It is metaphysically impossible to know these truth-values.Sorensen’s truthmaker gap epistemicism theory rests entirely on a firm commitment to classical logic,it is not only explicates the existence of absolute borderline case,but also interprets why the borderline case is unknowable.However,it faces many challenges,such as the conflict in commitment on“all no-no sentences are epistemic islands”,it is also incompatible with higher-order vagueness and so on.