Foundations Of Cognitive Science


Consider a recording of all of the speech utterances made by a particular individual over his or her entire lifetime.  Would this recording be an adequate model of this individual’s language (Fodor, 1968)?  Fodor argues that the recording is not an adequate model.  “At the very best, phonographs do what speakers do, not what speakers can do” (Fodor, 1968, p. 129).  The distinction between accounting for what was done versus what could have been done (but was not) is the distinction between performance and competence.  This distinction is critical in the study of language (Chomsky, 1965), where formal accounts of language are captured using grammars.  Grammars account for what sentences could be generated, but are not concerned with the production or use of particular expressions.  “When we say that a sentence has a certain derivation with respect to a particular generative grammar, we say nothing about how the speaker or hearer might proceed, in some practical or efficient way, to construct such a derivation.  These questions belong to the theory of language use” (Chomsky, 1965, p. 9).  A theory of language use is not a theory of linguistic competence, but is instead a theory of linguistic performance.  From the perspective that a grammar describes competence and not performance, it “attempts to specify what the speaker actually knows, not what he may report about his knowledge” (Chomsky, 1965, p. 8).


  1. Chomsky, N. (1965). Aspects Of The Theory Of Syntax. Cambridge, MA: MIT Press.
  2. Fodor, J. A. (1968). Psychological Explanation:  An Introduction To The Philosophy Of Psychology. New York: Random House.

(Added September 2010)