Katz–Postal hypothesis

A proposed property of TRANSFORMATIONS claimed by the American LINGUISTS Jerrold Katz (1932–2002) and Paul Postal (b. 1936) in 1964 in their book An Integrated Theory of Linguistic Descriptions, which had considerable influence on subsequent discussions of the relationship between SYNTACTIC and SEMANTIC analysis. Essentially, the hypothesis argued that all transformations should not change MEANING (they should be MEANING PRESERVING). In relation to the MODEL of GRAMMAR expounded by Noam Chomsky in Aspects of the Theory of Syntax (1965), it came to be argued that whenever two SENTENCES differ in meaning they will differ in DEEP STRUCTURE; and that accordingly, from a consideration of deep structure, the grammatical meaning of a sentence can be deduced, which can then provide the input to the semantic COMPONENT. The removal of meaning-changing transformations, on this view, would thus simplify the functioning of the semantic RULES. There are, of course, several areas of syntax which provide apparent COUNTER EXAMPLES to this hypothesis (such as TAG QUESTIONS, or the introduction of CONJUNCTIONS), and these provided the grounds of much subsequent discussion as to the validity of this and similarly motivated hypotheses. Considerable effort was made to apply the hypothesis to such cases, by reformulating the analyses (usually by adding extra ELEMENTS to the UNDERLYING structures involved).