The document discusses the history and debates around linguistic theories from the 1960s-1980s. It describes how Chomsky's theory of universal grammar was initially challenged by theorists like George Lakoff who argued meaning was more important than syntax. It then explains how Chomsky's theory of movement and extra syntactic structures like X-bar theory emerged to account for linguistic phenomena. In the 1990s, Chomsky introduced Minimalism which aimed to simplify theories by reducing unnecessary movement and structure.