THE 'INNATENESS HYPOTHESIS' AND EXPLANATORY MODELS IN LINGUISTICS I. THE INNATENESS HYPOTHESIS The 'innateness hypothesis' (henceforth, the 'I.H.') is a daring -or apparently daring; it may be meaningless, in which case it is not daringhypothesis proposed by Noam Chomsky. I owe a debt of gratitude to Chomsky for having repeatedly exposed me to the I.H.; I have relied heavily in what follows on oral communications from him; and I beg his pardon in advance if I misstate the I.H. in any detail, or misrepresent any of the arguments for it. In addition to relying upon oral communications from Chomsky, I have also relied upon Chomsky's paper 'Explanatory Models in Linguistics', in which the I.H. plays a considerable rble.
To begin, then, the I.H. is the hypothesis that the human brain is 'programmed' at birth in some quite specific and structured aspects of human natural language. The details of this programming are spelled out in some detail in 'Explanatory Models in Linguistics'. We should assume that the speaker has 'built in 'I a function which assigns weights to the grammars G1, Gz, G3,... in a certain class 2; of transformational grammars. 2; is not the class of all possible transformational grammars; rather all the members of 2; have some quite strong similarities. These similarities appear as 'linguistic universals' -i.e,, as characteristics of all human natural languages. If intelligent non-terrestrial life -say, Martiansexists, and if the 'Martians' speak a language whose grammar does not belong to the subclass 2; of the class of all transformational grammars, then, I have heard Chomsky maintain, humans (except possibly for a few geniuses or linguistic experts) would be unable to learn Martian; a human child brought up by Martians would fail to acquire language; and Martians would, conversely, experience similar difficulties with human tongues. (Possible difficulties in pronunciation are not at issue here, and may be assumed not to exist for the purposes of this argument.) As examples of the similarities that all grammars of the subclass 27 are thought to possess (above the level of phonetics), we may mention the active-