Shuhei Shimamura

This paper presents a new argument to defend the normativity of meaning, specifically the thesis that there are no meanings without norms. The argument starts from the observation inferentialists have emphasized that incompatibility relations between sentences are a necessary part of meaning as it is understood. We motivate this approach by showing that the standard normativist strategy in the literature, which is developed in terms of veridical reference that may swing free from the speaker’s understanding, violates the ought-implies-can principle, but ours does not. In addition, our approach is superior because, unlike the representationalist approach, it can be extended from declarative sentences to non-representational uses of language. In this paper, however, we only formulate the argument for the base case that involves incompatibility relations between declarative sentences. The goal is not to derive norms from something that is not normative, but to explicate the distinctive type of normativity that is built into meaning as it is understood by language-users. The explication proceeds in two steps. (1) For any sentence s a speaker understands, there is an incompatible sentence s’ the speaker understands to be incompatible with s. (2) In virtue of understanding this incompatibility of meanings, she ought not to be committed to both s and s’. This prohibition is not derived from instrumental practical reason, nor is it based on representational correctness, but its source is the incompatibility of meanings.

I present a sequent calculus that extends a nonmonotonic reflexive consequence relation as defined over an atomic first-order language without variables to one defined over a logically complex first-order language. The extension preserves reflexivity, is conservative (therefore nonmonotonic) and supraintuitionistic, and is conducted in a way that lets us codify, within the logically extended object language, important features of the base thus extended. In other words, the logical operators in this calculus play what Brandom (2008) calls expressive roles. Expressivist logical systems have already been proposed for propositional logics (see Hlobil, 2016, and Kaplan, 2018) but not for first-order logics. An advantage of this calculus over standard first-order calculi (e.g., those in Gentzen, 1935/1964) is that universally quantified variables behave as they should even in the presence of arbitrary nonlogical axioms. I claim that because of this robust well-behavedness of variables, this calculus also provides logical inferentialists with a way to understand the meanings of variables in terms of the roles those variables play in a wide range of inferences that is not limited to purely logical ones (e.g, mathematical inferences).

Motivated by semantic inferentialism and logical expressivism proposed by Robert Brandom, in this paper, I submit a nonmonotonic modal relevant sequent calculus equipped with special operators, □ and R. The base level of this calculus consists of two different types of atomic axioms: material and relevant. The material base contains, along with all the flat atomic sequents (e.g., Γ0, p |~0 p), some non-flat, defeasible atomic sequents (e.g., Γ0, p |~0 q); whereas the relevant base consists of the local region of such a material base that is sensitive to relevance. The rules of the calculus uniquely and conservatively extend these two types of nonmonotonic bases into logically complex material/relevant consequence relations and incoherence properties, while preserving Containment in the material base and Reflexivity in the relevant base. The material extension is supra-intuitionistic, whereas the relevant extension is stronger than a logic slightly weaker than R. The relevant extension also avoids the fallacies of relevance. Although the extended material consequence relation is defeasible and insensitive to relevance, it has local regions of indefeasibility and relevance (the latter of which is marked by the relevant extension). The newly introduced operators, □ and R, codify these local regions within the same extended material consequence relation.