of them had already been introduced by Zellig Harris in a previous work. He writes that Chomsky himself was "cautious" to "display deference" to prevailing linguistic research. His enthusiastic followers such as Lees were, by contrast, much more "confrontational". They sought to drive a "rhetorical wedge" between Chomsky's work and that of post-Bloomfieldians (i.e. American linguists in the 1940s et 1950s), arguing that the latter does not qualify as linguistic "science". Reception Impact on linguistics In an early review of the book, American structural linguist Charles F. Voegelin wrote that Syntactic Structures posed a fundamental challenge to the established way of doing linguistic research. He stated that it had the potential to accomplish "a Copernican revolution" within linguistics. Another American linguist Martin Joos called the Chomskyan brand of linguistic theory a "heresy" within the Bloomfieldian tradition. These early remarks proved to be prescient. American linguist Paul Postal commented in 1964 that most of the "syntactic conceptions prevalent in the United States" were "versions of the theory of phrase structure grammars in the sense of Chomsky". By 1965, linguists were saying that Syntactic Structures had "mark[ed] an epoch", had a "startling impact" and created a Kuhnian "revolution". British linguist John Lyons wrote in 1966 that "no work has had a greater influence upon the current linguistic theory than Chomsky's Syntactic Structures." British historian of linguistics R. H. Robins wrote in 1967 that the publication of Chomsky's Syntactic Structures was "probably the most radical and important change in direction in descriptive linguistics and in linguistic theory that has taken place in recent years". Another historian of linguistics Frederick Newmeyer considers Syntactic Structures "revolutionary" for two reasons. Firstly, it showed that a formal yet non-empiricist theory of language was possible. Chomsky demonstrated this possibility in a practical sense by formally treating a fragment of English grammar. Secondly, it put syntax at the center of the theory of language. Syntax was recognized as the focal point of language production, in which a finite set of rules can produce an infinite number of sentences. Subsequently, morphology (i.e. the study of structure and formation of words) and phonology (i.e. the study of organization of sounds in languages) were relegated in importance. American linguist Norbert Hornstein wrote that before Syntactic Structures, linguistic research was overly preoccupied with creating hierarchies and categories of all observable language data. One of the "lasting contributions" of Syntactic Structures is that it