  Because they are defending the view that all of UG is inborn,  Chomskyans must be credited with holding that the primary data are  impoverished quite generally. That is, if the innateness of UG  tout court is to be supported by poverty of the stimulus  considerations, the idea must be that the cases that nativists  discuss in detail (polar interrogatives, complex auxiliaries, etc.)  are but the tip of the unlearnable iceberg. Nativists quite  reasonably do not attempt to defend this claim by endless enumeration of cases. Rather, they turn to another kind of argument to support  the ‘global impoverishment’ position. This argument is  sometimes called the ‘Logical Problem of Language  Acquisition’; here, we will call it ‘The Unlearning  Problem.’ It will be discussed in section 3.