Abstract
A grammar is primarily a device which accounts for the underlying processes of sentence formation. How does this idea arise? Chapter four of Syntactic Structures, dedicated to the relationship between generative grammar and distributionnal syntax, does not stress this point. It is not sufficient to set forth the failure of discovery procedures, because Chomsky, in order to solve the problem of justification, uses quite a similar method to his predecessors'. The concept of grammar appears only in reference to the problem of projection. But it belongs to psychology. It aims to account for the use of language and to contribute to a model of performance. The linguist's strategy would then be dictated to him by psychology.