Many classically valid meta-inferences fail in a standard supervaluationist framework. This allegedly prevents supervaluationism from offering an account of good deductive reasoning. We provide a proof system for supervaluationist logic which includes supervaluationistically acceptable versions of the classical meta-inferences. The proof system emerges naturally by thinking of truth as licensing assertion, falsity as licensing negative assertion and lack of truth-value as licensing rejection and weak assertion. Moreover, the proof system respects well-known criteria for the admissibility of inference rules. Thus, supervaluationists can provide an account of good deductive reasoning. Our proof system moreover brings to light how one can revise the standard supervaluationist framework to make room for higher-order vagueness. We prove that the resulting logic is sound and complete with respect to the consequence relation that preserves truth in a model of the non-normal modal logic NT. Finally, we extend our approach to a first-order setting and show that supervaluationism can treat vagueness in the same way at every order. The failure of conditional proof and other meta-inferences is a crucial ingredient in this treatment and hence should be embraced, not lamented.

许多经典有效的元推理在标准的超估值主义框架中失败。据称，这阻止了超级估价主义提供良好的演绎推理。我们为超估价逻辑提供了一个证明系统，其中包括经典元推理的超估价可接受版本。证明系统是通过将真实视为许可断言，将虚假视为许可否定断言，将缺乏真值视为许可拒绝和弱断言而自然出现的。此外，证明系统尊重推理规则的可接受性的众所周知的标准。因此，超估价主义者可以提供良好的演绎推理的解释。此外，我们的证明系统揭示了如何修改标准的超级估值主义框架，为更高阶的模糊性腾出空间。新台币。最后，我们将我们的方法扩展到一阶设置，并表明超估值主义可以在每个阶上以相同的方式处理模糊性。条件证明和其他元推理的失败是这种处理中的一个关键因素，因此应该被接受，而不是哀叹。