'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 actually begins the essay with a reservation regarding the word "event", since it implies a meaning "which is precisely the function of structural - or structuralist - thinking to reduce or suspect" (278). This, in my opinion, refers to the emphasis, within structuralist discourse, on the synchronous analysis of systems and the relationships within them, as opposed to diachronic schemes committed to discovering genetic and teleological contents in the transformations of history. The event that the essay documents is that of a definitive epistemological break with structuralist thought, of the advent of post-structuralism as a movement that critically confronts structuralism, but also with traditional humanism and empiricism - here it becomes the “structurality of the structure” (278) itself that begins to be thought. Immediately, however, Derrida notes that he does not pretend to place himself "outside" the critical circle or the totality to criticize in this way. While the function of the center of the structure is identified as that which reduces the possibility of thinking this structurality of the structure, even if «it has always been at work» (278), that is, it has always been an economic and economizing factor within philosophy that limits the play of structure – where I understand play as associated with “uneconomic” deconstructive notions such as complementarity, trace and difference, Derrida observes that “even today the notion of a structure devoid of any center [sic] represents the 'unthinkable itself' (279). This seems to present a conundrum. Indeed, even if the center closes the game, it apparently cannot be done without, or at least, it cannot be simply discarded without re-emerging somewhere else within the totality. The enigma is in fact a paradox and a coherent contradiction of classical thought, which echoes the Freudian theory of neurotic symptoms where a symbol expresses at the same time the desire to satisfy and repress a given impulse (339). Therefore "contradiction expresses the strength of a desire" (279). The center is, according to Derrida, both inside and outside the totality – it is an elsewhere (Derrida's italics) of the totality. It is also a difficult and paradoxical concept to understand. The notion of full presence informs metaphysical discourses in movements that aim to discover the origins or decode, even prophesy, the purposes of philosophical and metaphysical thought..