a1 University of Iowa
The main goal of linguistic research is to develop a theory of grammar, i.e. a set of universal principles to characterize human language. Since languages vary superficially, this goal is achieved only when it is shown that superficial differences among languages can be accounted for by the theory of grammar. Clearly, then, the more that superficial differences among languages can be accounted for by universal principles, the more the field will advance. This conclusion is best stated by Perlmutter (1971): … progress in linguistics depends on extracting as much as possible from grammars of particular languages and formulating general principles from which the facts of particular languages will follow as automatic consequences….
(Received February 06 1979)
 I am indebted to Gail Ardery and Catherine O. Ringen for reading various drafts of this paper, for their valuable comments, and for their stimulating discussions through the preparation of this paper.