While Chomsky has developed different versions of his theories over the years, often abandoning his own followers of previous versions, most commentators agree that overall themes and trends in his thought amount to the claim that linguistic ability or language in a general syntactic or grammatical sense is “hard wired” into the human brain as a physical structure enabling a linguistic “faculty.”

Chomsky has posited a “Universal Grammar” that limits the group of possible human languages. In philosophical terms, this is a rationalist, rather than an empiricist, approach to language. Thus, in Cartesian Linguistics (1966), Chomsky clearly stated, in affinity with René Descartes (1596–1650), that human language is innate and that human beings universally share this capacity. It should be noted, however, that Chomsky is a materialist concerning mental activity, whereas Descartes believed that the mind was a non-material substance.