The Problem of Validity Proofs

In philosophical contexts, logical formalisms are often resorted to as a means to render the validity and invalidity of informal arguments formally transparent. Since Oliver (1967) and Massey (1975), however, it has been recognized in the literature that identifying valid arguments is easier than identifying invalid ones. Still, any viable theory of adequate logical formalization should at least reliably identify valid arguments. This paper argues that accounts of logical formalization as developed by Blau (1977) and Brun (2004) do not meet that benchmark. The paper ends by suggesting different strategies to remedy the problem.