And that this movement, unique in style, was so profound that it permitted the thinking, within language, of concepts like those of the sign, technique, representation, language. The system of language associated with phonetic-alphabetic writing is that within which logocentric metaphysics, determining the sense of being as presence, has been produced.
Consequently, reconsidering the order of dependence prescribed by Saussure, apparently inverting the relationship of the part to the whole, Barthes in fact carries out the profoundest intention of the Course:
From now on we must admit the possibility of reversing Saussure’s proposition some day: linguistics is not part, even if privileged, of the general science of signs, it is semiology that is a part of linguistics.
…one asks the question of the transcendental origin of the system itself, as a system of the objects of a science, and, correlatively, of the theoretical system which studies it: here of the objective and “deductive” system which glossematics wishes to be. Without that, the decisive progress accomplished by a formalism respectful of the originality of its object, of “the immanent system of its objects,” is plagued by a scientificist objectivism, that is to say by another unperceived or unconfessed metaphysics.
— Jacques Derrida, Of Grammatology