Robert J. Matthews

This paper defends the commonsense conception of linguistic competence according to which linguistic competence involves propositional knowledge of language. More specifically, the paper defends three propositions challenged by Devitt in his Ignorance af Language. First, Chomskian linguists were right to embrace this commonsense conception of linguistic cornpetence. Second, the grammars that these linguists propose make a substantive claim about the computational processes that are presumed to constitute a speaker’s linguistic competence. Third, Chomskian linguistics is indeed a subfield of psychology, in the business of characterizing the linguistic competence of speakers.

Putnam and Searle famously argue against computational theories of mind on the skeptical ground that there is no fact of the matter as to what mathematical function a physical system is computing: both conclude (albeit for somewhat different reasons) that virtually any physical object computes every computable function, implements every program or automaton. There has been considerable discussion of Putnam's and Searle's arguments, though as yet there is little consensus as to what, if anything, is wrong with these arguments. In the present paper we show that an analogous line of reasoning can be raised against the numerical measurement (i.e., numerical representation) of physical magnitudes, and we argue that this result is a reductio ad absurdum of the challenge to computational skepticism. We then use this reductio to get clearer about both (i) what's wrong with Putnam's and Searle's arguments against computationalism, and (ii) what can be learned about both computational implementation and numerical measurement from the shortcomings of both sorts of skeptical argument.