This suggests that a subset of English sentences interesting on quite independent grounds is unspecified with respect to problems of phonemic and morphological analysis. To characterize a linguistic level L, any associated supporting element delimits the strong generative capacity of the theory. Conversely, an important property of these three types of EC is not quite equivalent to the system of base rules exclusive of the lexicon. I suggested that these results would follow from the assumption that relational information suffices to account for an abstract underlying order. Clearly, the theory of syntactic features developed earlier is rather different from nondistinctness in the sense of distinctive feature theory.
see also: WikiPedia -- Chomskybot