 Since Stevenson suggests that he might explain the compositionality of atomic sentences in terms of functions from the dispositions of a sentence’s parts to a set of resulting dispositions, it is plausible that he might also wish to extend his theory in a similar way to explain the compositionality of complex sentences. Whether such a theory could sustain additional scrutiny is debatable. For more in-depth but accessible discussion of emotivist and expressivist attempts to respond to the Frege-Geach Objection, see especially Schroeder 2008 and 2010 and the entry on  moral cognitivism vs. non-cognitivism.