One is reminded here of Chomsky's (1966, p.43) much-quoted scepticism about
the significance of linguistics for language teaching. But what Chomsky in fact
says is that linguistics and psychology are associated with ways of approaching
'the problems of language teaching from a principled point of view', in other
words, the theoretical disciplines provide a reference for establishing principles
of approach. He only questions whether these disciplines can inform pedagogic
technique directly.