The proposal that a grammar should

The proposal that a grammar should be considered as a device which generates all and only the well-formed sentences of a language, which has already had a profound effect upon linguistics in general, has begun to exert some influence on the more particular (if less well defined) subject of stylistics. To understand this, it is necessary to consider the way in which one tests such a grammar. This includes checking that for any grammatical sentence we observe there exists in the grammar a partially ordered sequence of formulae which would generale it. It is an inevitable outcome of any prolonged examination of a theory of this kind that there will arise cases which can be generated but with regard to which a decision as to whether or not they constitute a genuine example of the phenomena the theory is supposed to cover cannot be arrived at merely by reference to existing data: cf. Weyl (1949: 150). In linguistics this is called the problem of GRAMMATICALNESS. (Chomsky, 1957: 15)