Summary |
The term logical expressivism refers to several
related but distinct theories in the literature. What they share, roughly, is
the idea that a satisfactory account of certain philosophical issues regarding
logic must appeal to what one (characteristically) does with logical vocabulary
or statements, rather than just what is represented by them. Different versions
of logical expressivism differ in at least two respects: (a) the philosophical
issue that is the explanatory target, and (b) what they claim one does with
logical statements or vocabulary. The most prominent advocate of logical
expressivism is Robert Brandom. According to Brandom, the characteristic
expressive function of logical vocabulary is “to make inferential relations
explicit—that is, to explicitly endorse or reject pieces of reasoning by making
assertions using logical vocabulary, rather than merely implicitly doing so by
reasoning in certain ways. Thus, an account of what makes some vocabulary logical
vocabulary must appeal to the fact that this vocabulary allows one to express
what follows from what and what is incompatible with what. Here the relevant
kind of inferential relations includes more than just logical relations; it includes
what Brandom calls material implication and incompatibility, such as the
lexical entailment from something being blue to it being colored. The
explanatory target of this brand of logical expressivism is the demarcation of
logical vocabulary, and what logical vocabulary allows one to do is to explicitly
undertake commitments regarding consequence and incompatibility. Jaroslav
Peregrin advocates a similar version of logical expressivism. Others use logical
expressivism to denote a claim that is closer to expressivism in meta-ethics,
e.g., the claim that endorsing an entailment is not a cognitive state; rather, statements
about entailment express pro-attitudes toward drawing corresponding inferences.
In this case, the explanatory target is an account of what it means to endorse
entailments, and what we do with logical statements is to express non-cognitive
mental states. What unifies this account of logical expressivism with those of
Brandom and Peregrin is the dismissal of the task of finding a place for
logical facts in (discourse-independent) nature. Logical expressivism has close
ties to semantic inferentialism, logical inferentialism, proof-theoretic semantics,
and logical deflationism. Moreover, logical expressivists are often interested
in how one can express claims about consequence and incompatibility in the
object language of a logic. |