[Part II The crash-proof debate, Grammaticality, interfaces, and UG]
It is argued that the notions “well-formedness” and “grammaticality,” inspired by formal-language theory, are not necessarily relevant for the study of natural language. The assumption that a [± grammatical] distinction exists, i.e. that I-language generates only certain structures but not others, is empirically questionable and presumably requires a richly structured UG. Some aspects of “crash-proof” models of syntax that assume such a distinction are discussed and contrasted with an alternative proposal (the Minimalist Program as pursued by Chomsky), which dispenses entirely with grammaticality, allowing syntax to generate freely. The latter program aims not at distinguishing “grammatical” from “ungrammatical” sentences, but at providing a true theory of the mechanisms that assign interpretations to structures at the interfaces.