Steven Pinker's The Language Instinct is one of the most recent, comprehensive and ambitious attempts to account for the origin of language. It approaches the topic from within the Chomskyan framework (Chomskyan linguists have generally remained silent about language evolution). Language, he says, is not a cultural artifact but `a distinct piece of the biological make up of the brain`. We would all agree that a biological and essentially evolutionary approach is desirable, though 'language instinct' already begs many questions. Chomsky's concept of Universal Grammar is well known: the brain must contain a recipe or program that can build an unlimited number of sentences from a finite list of words; the program may be called a mental grammar; children - 'grammatical geniuses' - must innately be equipped with a plan common to the grammars of all languages that tells them how to extract the syntactic patterns from the speech of their parents. However Pinker does not share Chomsky's scepticism about whether Darwinian natural selection can explain the origins of the language organ. This paper seeks to identify where, at a number of important points, Pinker's account seems unsatisfactory, for example: the idea that language could have developed, like the eye, by minute steps, under the pressure of natural selection, the idea that eventually neuroscientists will be able to locate a 'language organ', or behavioural geneticists discover a grammar gene, the postulation of a uniform distinct language of thought, mentalese, to be translated into any particular spoken language, his discussion of the arbitrariness of the sign, his account of the acquisition of language by children.