Campbell, Kirsten. Jacques Lacan and Feminist Epistemology. Florence, KY, USA: Routledge, 2004.
As in L’envers, in Encore Lacan represents each of the discourses by a schema which sets out the relation of four terms: b, S2 , a and $. These terms designate respectively: the master signifier (le signifiant maître), knowledge (le savoir), surplus jouissance (le plus-de-jouir) and the subject (le sujet) (S20: 17).
S1 represents the master signifier, the symbolic element that represents the subject for another signifier. The master signifier marks the subject’s position within the signifying chain and hence within the discursive social tie.
S2 designates the symbolic field, the chain or network of signifiers that form the subject. For this reason, S1, S2 represents the knowledge of the subject. It describes both the form of the subject’s knowledge, for example, academic, psychoanalytic and so on, and the form of knowledge of the subject, such as the differing conceptions of the subject within the university and psychoanalysis.
The term a represents the ‘left-over’ or remainder of discourse. That remainder is the jouissance produced by, and surrendered to, language in the taking up of a speaking position by the subject. The a is an unassimilable excess to the discourse. There is no signifier of the a, as it is not possible to represent it in the signifying economy of the discourse. The subject attempts to structure its relationship to this unassimilable remainder by rendering it as an imaginary object – the objet petit a. The a thus both functions in the imaginary register, in which it appears as an imaginary object filled with phantasmic content, and in the symbolic register, in which it marks the excluded term of discourse, the gap in or void of its symbolic structure. For this reason, the a ‘stands simultaneously for the imaginary fantasmic lure/screen and for that which this lure is obfuscating, for the void behind the lure’ (Zizek 1998a: 80).
The fourth term, $, represents the subject. The subject does not represent the S of the conscious subject but the ‘true’ psychoanalytic subject of the unconscious. $ designates the barred subject, in which the S of the conscious subject is struck through because of its division by the unconscious. The schemas of the discourses describe the relation of each of these terms, S1 , S2 , a and $ (50).