Abstract

This article focuses on the relevance of computational complexity for cognition. The syntactic items may be expressions that are surface strings. But in general, strings are syntactically ambiguous in that they can be generated in more than one way from atomic expressions and operations. The semantic function must take disambiguated items as arguments. When expressions are ambiguous, expressions cannot be the arguments. Instead, it is common to take the arguments to be terms, whose surface syntax reflects the derivation of the string. The semantic function differs in one other important respect from an arithmetic function, since it maps entities between domains, from a syntactic to an ontic or conceptual domain of meanings. Compositionality helps to explain the rate of success in linguistic communication when the sentence used or the content communicated is new.