Right and Wrong Reasons for Compositionality

In this paper I would like to cast a critical look on the potential reasons for compositionality. I will, in particular, evaluate if and to which extent the most often cited reasons in favor of compositionality, viz. productivity, systematicity and inferentiality – each taken as properties of either language or cognition – may be justly regarded as justifications for compositionality. The results of this investigation will be largely negative: Given reasonable side-constraints, the reason of productivity faces counterexamples of productive languages that cannot be evaluated compositionally. Systematicity has less to do with compositionality than with the existence of semantic categories. The belief that inferentiality is only warranted in compositional languages is a pious hope rather than a certainty. Alternative reasons will be explored at the end of the paper. Before I turn to its reasons, I will explicate the notion of compositionality and say something about its alleged vacuity.