“Structure, sign and play in the discourse of the human sciences” (Derrida, 1978: 278 – 293) can be read as the document of an event, although Derrida begins by reality through the essay with a reservation on the word “event”, because it includes a meaning “that it is precisely up to structural – or structuralist – thought to reduce or suspect” (278). This, I infer, refers to the emphasis placed in structuralist discourse on the synchronous analysis of systems and the relationships within them, as opposed to diachronic patterns busy uncovering the genetic and teleological content of transformations of the 'history. The event documented by the essay is that of a definitive epistemological break with structuralist thought, of the advent of post-structuralism as a critical movement of structuralism, but also of traditional humanism and empiricism – it becomes here the “structurality of the structure” (278) itself which begins to be thought. . However, Derrida immediately notes that he does not claim to place himself “outside” the critical circle or the totality in order to issue such a critique. While the function of the center of the structure is identified as that which reduces the possibility of thinking about this structurality of the structure, even if “it has always been at work” (278), that is to say that it has always been an economic and saving factor. Within the framework of Western philosophy limiting the play of structure – where I understand play to be associated with “non-economic” deconstructive notions such as supplementarity, trace and difference, Derrida notes that “even today, the notion of structure devoid of any center [sic] represents the unthinkable itself” (279). This seems to present a conundrum. Because if the center closes the game, this apparently cannot be done without, at least, it cannot be simply rejected without it reappearing elsewhere in the totality. The enigma is in fact a paradox and a consistent contradiction of classical thought, which echoes Freud's theory of neurotic symptoms where a symbol expresses both the desire to fulfill and suppress a given impulse (339). Thus, “the contradiction expresses the force of a desire” (279). The center is, according to Derrida, both inside and outside of the totality – it is an elsewhere (emphasis by Derrida) of the totality. It is also a difficult and paradoxical concept to grasp. The notion of full presence illuminates metaphysical discourses in movements aiming to discover the origins or to decode, even prophesy, the aims of philosophical and metaphysical thought..