theoretical claims of Chomsky in Syntactic Structures. In 2015, neuroscientists at New York University conducted experiments to verify if the human brain uses "hierarchical structure building" for processing languages. They measured the magnetic and electric activities in the brains of participants. The results showed that "[human] brains distinctly tracked three components of the phrases they heard." This "[reflected] a hierarchy in our neural processing of linguistic structures: words, phrases, and then sentences—at the same time." These results bore out Chomsky's hypothesis in Syntactic Structures of an "internal grammar mechanism" inside the brain. Criticisms Erroneous idealization In his 1964 presidential address to the Linguistic Society of America, American linguist Charles Hockett considered Syntactic Structures one of "only four major breakthroughs in modern linguistics". But he rapidly turned into a fierce critic of Chomskyan linguistics. By 1966, Hockett rejected "[Chomsky's] frame of reference in almost every detail". In his 1968 book The State of the Art, Hockett writes that Chomsky's main fallacy is that he treats language as a formal, well-defined, stable system and proceeds from this idealized abstraction. Hockett believes such an idealization is not possible. He claims that there is no empirical evidence that our language faculty is, in reality, a well-defined underlying system. The sources that give rise to language faculty in humans, e.g. physical genetic transmission and cultural transmission, are themselves poorly defined. Hockett also opposed Chomsky's hypothesis that syntax is completely independent of the study of meaning. Non-empiricism Contrary to Hockett, British linguist Geoffrey Sampson thought that Chomsky's assumptions about a well-defined grammaticality are "[justified] in practice." It brought syntax "within the purview of scientific description". He considers it a "great positive contribution to the discipline". However, he maintains that Chomsky's linguistics is overly "intuition-based". For him, it relies too much on native speakers' subjective introspective judgments about their own language. Consequently, language data empirically observed by impersonal third parties are given less importance. Influence of The Logical Structure of Linguistic Theory According to Sampson, Syntactic Structures largely owes its good fortune of becoming the dominant theoretical paradigm in the following years to the charisma of Chomsky's intellect. Sampson writes that there are many references in Syntactic Structures to Chomsky's own The Logical Structure of Linguistic Theory (LSLT) in matters regarding the formal underpinnings of Chomsky's approach, but LSLT was not widely available in print for decades. Nevertheless, Sampson's argument runs, Syntactic Structures, albeit "sketchy", derived its