Formal Properties Of Rule Orderings In Linguistics

The discovery in the late 1960's that standard linguistic theory (of Chomsky's Aspects) was equivalent in generative power to unrestricted rewrite rules caused linguists to search for a "stronger linguistic metatheory". It seemed to some of these researchers that this meant describing linguistic theory by means of rules which were more restricted than type 0 languages. Such a view we call the L-view of constraints on linguistic theory: it advocates constraining the allowable rules in such a way that legitimate grammars can no longer generate arbitrary r.e. sets, but only some subset of them. To other researchers this discovery meant rather that one should place restrictions on linguistic theory so that the kinds of grammars allowed would be limited, regardless of whether such limitations affected the generative power of the theory. We call this the G-view of constraints. The Land G-views are not equivalent limitations. For example, a G-view limitation on the class of regular grammars that any legitimate grammar be right-embedding is not thereby a L-view limitation, since this does not effect an alteration in generative power of the grammars allowed. The G-view is avowedly psychological; according to it, the point of placing constraints on grammars is to lessen directly the language learner's burden of choosing the correct grammar from all the possible ones. For the L-view, this is a side effect of disallowing whole classes of grammars in the first place.