it gives less value to the gathering and testing of data. Nevertheless, American linguistics changed course in the second half of the 20th century as a result of Syntactic Structures. Background Situatedness in linguistic theory At the time of its publication, Syntactic Structures presented the state of the art of Zellig Harris's formal model of language analysis which is called transformational generative grammar. It can also be said to present Chomsky's version or Chomsky's theory because there is some original input on a more technical level. The central concepts of the model, however, follow from Louis Hjelmslev's book Prolegomena to a Theory of Language, which was published in 1943 in Danish and followed by an English translation by Francis J. Whitfield in 1953. The book sets up an algebraic tool for linguistic analysis which consists of terminals and inventories of all different types of linguistic units, similarly to terminal and nonterminal symbols in formal grammars. First, it functions as a descriptive device, or as Hjelmslev explains it: When this work is done to a satisfactory level, it will also become possible to predict all the grammatical sentences of a given language: Hjelmslev also points out that an algorithmic description of a language could generate an infinite number of products from a finite number of primitive elements: These are logical consequences of the mathematical systems proposed by David Hilbert and Rudolf Carnap which were first adopted into linguistics by Hjelmslev whose ideas are reiterated by Chomsky: Chomsky likewise states that a recursive device such as closed loops would allow the grammar to generate an infinite number of sentences. There are, however, some major points of divergence from Hjelmslev's conception. Hjelmslev was a structuralist and applied mathematical models to Ferdinand de Saussure's concept of language as an interactive system of meaning and form. Although the Bloomfieldian school of early to mid-20th century linguists were nicknamed 'American structuralists', they essentially rejected the basic tenets of structuralism: that linguistic form is explained through meaning, and that linguistics belongs to the domain of sociology. Instead, the idea of language endorsed by Leonard Bloomfield and his followers derived from William Wundt's mentalistic psychology which was replaced by behavioural psychology in Bloomfield's 1933 book Language. This led to the separation of syntax from semantics as not an observable link in a stimulus–response chain. Chomsky, like Harris and other American linguists, agreed that there is no causal link