In the past decade various linguists and philosophers (e.g. Pagin, Pelletier, Recanati, Westerståhl, Lasersohn) have proposed a weakening of the standard interpretation of compositionality for propositional content. Their move is motivated by the desire to accommodate radical forms of context sensitivity within a systematic account of natural languages. In this paper I argue against weakening compositionality in the way proposed by them. I argue that weak compositionality fails to provide some of the expected benefits of compositionality. First, weak compositionality fails (...) to provide systematic meaning-rules which can handle forms of context-sensitivity that are not amenable to explanation in terms of a fixed and limited set of contextual parameters. Secondly, I argue that weak-compositionality fails to play any role in explaining speakers’ ability to calculate the semantic values of complex expressions. I conclude that weak compositionality is not a viable alternative to standard interpretations of compositionality, and that it doesn’t offer an acceptable way to accommodate radical forms of context-sensitivity within a systematic account of natural languages. Given the central role that weak-compositionality plays in recent approaches to natural language (e.g. in truth-conditional pragmatics) this also casts doubt on the viability of these projects. (shrink)