I suggested that these results would follow from the assumption that the descriptive power of the base component is unspecified with respect to a descriptive fact. For one thing, the speaker-hearer's linguistic intuition is necessary to impose an interpretation on an abstract underlying order. On our assumptions, the earlier discussion of deviance cannot be arbitrary in a parasitic gap construction. Note that a case of semigrammaticalness of a different sort may remedy and, at the same time, eliminate a stipulation to place the constructions into these various categories. Summarizing, then, we assume that most of the methodological work in modern linguistics does not affect the structure of the system of base rules exclusive of the lexicon.
see also: WikiPedia -- Chomskybot