ABSTRACT
As I read and reread the chapters of the book, I was aware of two things: First, the chapters speak for themselves and there is no need to reiterate what the authors have so eloquently conveyed in their writings. Second, the issue addressed in all the chapters, whether directly or indirectly, is that of modularity. I have therefore taken the opportunity to reexamine the merit of the evidence that has been brought to bear on the modularity thesis. My concern is chiefly with data from pathology. Within the literature on acquisition, the term modularity has been affected by the notion of modules in Chomsky’s theory of Government and Binding (GB). The modules of GB are Theta-theory, Case theory, Control, Binding, the Empty Category principle and X-theory. Acquisition data that can be explained in terms of principles governing one of these modules enhance the plausibility of the particular principles, as well as the specific modular organization of language, as stated in this model. More generally, modularity has been used loosely to refer to the presence of formal syntactic knowledge in children that seems independent of meaning considerations. Such studies in normal, as well as in pathological, populations of children address the issue of internal modularity, that is, the modular organization of the language system. For the purpose of illustration, let me mention a few studies in pathology that have looked at specific subsystems within grammar and have argued for or against internal modularity.
