• Korean Journal of Logic
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• v.18 no.3
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• pp.307-335
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• 2015

An important component in Prawitz's and Dummett's proof-theoretic accounts of validity is the condition for validity of open arguments. According to their accounts, roughly, an open argument is valid if there is an effective method for transforming valid arguments for its premises into a valid argument for its conclusion. Although their conditions look similar to the proof condition for implication in the BHK explanation, their conditions differ from the BHK account in an important respect. If the premises of an open argument are undecidable in an appropriate sense, then that argument is trivially valid according to Prawitz's and Dummett's definitions. I call this 'the triviality problem'. After a brief exposition of their accounts of proof-theoretic validity, I discuss triviality problems raised by undecidable atomic sentences and by Godel sentence. On this basis, I suggest an emendation of Prawitz's definition of validity of argument.

• Korean Journal of Logic
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• v.15 no.1
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• pp.53-85
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• 2012

There are various views in the boundary of deflationism of truth in regarding the nature and role of truth. This paper surveys the issue on how the core thesis uniting the deflationism is characterized. First, I will examine some comments on what is the central thesis supported or rejected by the deflationists and inflationists, mainly discussing Armour-Garb and Beall's work, and will show on which aspects they are unsatisfying. From this, I will suggest these statements: first, the central cores of deflationism are conceptual fundamentality and explanatory exhausting. Second, the particularity thesis, understood in an alternative way, cannot be a central claim of deflationism. Third, another important claim from deflationists, the expression thesis, can be derived from the two main thesis above. But it is still not clear enough what the non-expressive explanatory role of truth, which is denied by the expression thesis. So I will check some possible clarifications on it and discuss why they should be rejected. And I will introduce Dummett's view on the role of truth condition in truth conditional explanation of meaning, and I will claim that if Dummett is right why the role must be a inflated one. Finally, I will suggest a further implication that the understanding on the both sides can be widened by connecting considerations on both views.