From Sarah Kay's Žižek: A Critical Introduction (London: Polity Press, 2003), pp. 38-41:
Žižek first treats the topic of universality at length in For They Know Not, and continues unabated in recent writings, with particularly extended discussions in The Ticklish Subject (chapter 3) and Contingency, Hegemony, Universality ('Da Capo Senza Fine'). Universality is central to Žižek's thinking about sexual difference, history and politics, and I shall be returning to it in chapters 4 and 6.
On the psychoanalytic side, Žižek's first account of universality runs like this (based on For They Know Not, especially 21-7). The universal order is the symbolic order, or big Other, which provides the conceptual grid with which we construe the world. However, our conceptual mapping is impaired by the fact that the planes of signifier and signified are out of kilter with one another. The reason why this comes about is that one of the signifiers has no corresponding signified; it does not introduce a content into the linguistic system, but merely insinuates difference. The perpetually moving place to which it points is that of the 'lack' in the symbolic order, the primordial lack of 'castration'. This signifier is represented as S1 because, having no signified, it is singular, whereas all the other signifiers are double, hence S2. S1 is also singular in the sense that it is unique among the signifiers; hence it can also be referred to as the 'unary feature' (Lacan's trait unaire; see Glossary, SIGNIFYING CHAIN).
The unary feature acts as the prop of individual identification at the symbolic level. How I position myself as an individual depends on how I attach myself to this signifier of pure difference. However, as the empty space in the set, S1 also both determines and effectively takes on the value of all the other signifiers (S2). The result is that, as well as being a pure (qualitative) singular, it assumes the role of the (quantitative) particular. That is, instead of being utterly unique, it appears as just one of a set, and hence as correlated with the universal. Thus inflated with the meaning of the other signifiers, it gives the impression of totalizing the whole field of signification. This is why it is also called the master signifier, or 'quilting point' (Lacan's point de capiton), the signifier that 'quilts' the field of meaning. For example, the claim that we are a 'free society' acts as a political quilting point that is, in itself, meaningless--a flag to wave at cultures we wish to disparage, and that has nothing to do with the extent to which we actually are or are not free (for instance, one way we regulalry show we are a 'free society' is by locking up people who threaten our 'freedom'). But in everyday thinking, the empty term 'free society' becomes 'filled out' with all the aspects of our society which we treasure (family life, nice cars, TV, etc.).
Via a process of double reflection, then, S1 appears first as negating the rest of the set, S2--that is, as unique relative to its fullness--and next, via a negation of this negation, when the rest of the set is reflected into it, as typifying the universal in the form of the particular. For instance, when I identify myself relative to the unary feature, I don't normally think of myself as absolutely unique, as a point of difference. Instead, I embrace some ideologically totalizing view of myself: say, as a successful academic and mother of three. In this way, I make the transition from the singular to the particular which in turn evokes the universals 'academic success' and 'motherhood'.
A Hegelian terminology has already crept into this exposition, and clearly Žižek's development of Lacan owes much to Hegel. Hegel too is interested in this triadic construction of the concept as comprising three 'moments', singular, particular and universal, which are dialectically related to one another. Thus, for instance, the particular can pass into the universal and back, says Žižek, like the passage round a Moebius band, where what we thought were two distinct sides are in fact one continuous one (For They Know Not, 46). The capacity for each 'moment' to pass into another also means, paradoxically, that the universal can be located in the particular. In this way, the universal is 'always-already part of itself, comprised within its own elements' (ibid.); this capacity to appear among its own particulars is illustrated by Lacan's often repeated quip, 'I have three brothers, Paul, Ernest and myself'.
Another way in which the universal is located in one of the particulars is via the exception. Žižek endorses as authentically Hegelian the claim that 'the exception proves the rule', since it is precisely from our awareness of an exception to it that the existence of a rule can be inferred. A more concrete instance of the correlation between the exception and the universal is furnished by Marx's account of the commodity (For They Know Not, 124). All commodities are defined as being goods which can be exchanged for money, except for money itself. What universalizes the notion 'commodity' is the fact that there exists one commodity, money, which is the exception to the set.
Returning now to Lacan, this account of the universal as correlative with its exception corresponds exactly with how he defines masculinity in the 'formulae of sexuation' in Seminar XX. The 'exception which proves the rule' of masculinity is the mythical father in Freud's Totem and Taboo, the father who enjoyed uncontested sexual possession of all the women in the tribe before being murdered by his sons. Through guilt for their act, the sons became subject to the law of inhibition and repression ('castration') that characterizes all men as a result of the very fact that there was one--their father--who claimed exemption from it. As Žižek puts it,
"Lacan's basic premiss is that the leap from the general set of 'all men' into the universal 'man' is possible only through an exception: the universal (in its difference to the empirical generality) is constituted through the exception; we do not pass from the general set to the universality of One-Notion by way of adding something to the set but, on the contrary, by way of subtracting something from it, namely the 'unary feature' [trait unaire] which totalizes the general set, which makes out of it a universality." (For They Know Not, 123)
The correspondence between Hegel and Lacan looks complete. However, a new twist (or dialectical reversal) is about to be effected.
It comes in the form of the feminine formula of sexuation, which proposes a different relationship to the universal from the masculine one: one in which the signifying order plays a greatly diminished role. Women, like men, are subject to inhibition and repression, says Lacan--indeed, they are so without exception--but they are so incompletely and inconsistently. The result of this, according to Lacan, is that 'woman' is not fully actualized as a universal. I shall be returning to this problematic claim in chapter 4; what is relevant to the present discussion is the way Žižek presents this 'not-quite-universal' of the feminine. This is the 'non all' which we encountered when reviewing the so-called immanentism of the Hegelian dialectic. It means that the symbolic fiction of the universal, instead of being tugged into shape by S1, is, on the contrary, exposed as deficient and leaky. The agent of this exposure is an absolutely contingent object, here identified as the objet a. This is what blocks or holds open the place of lack in the symbolic order that is commandeered, on the side of the symbolic, by S1. The complex arguments concerning S1 were not a red herring--the master signifier is indeed a clue to the way the universals of ideology and identity, not to mention masculinity, are constructed--but they need to be subordinated to this new view of universality.
So now the objet a and not S1 is proposed as what impedes (and provokes) the universal. Objet a is the fantasy object that plugs the gap of the primary repression and provides the subject's original defence against 'castration'. It is, as it were, the traumatic underside of S1. The 'lack' which it gives the illusion of filling out is, Žižek is arguing, the emptiness on which the universal founders: the conceptual world cannot 'say it all'; there is always something which escapes. Also, because of its connection with trauma, the space of objet a discloses the dimension of violence in the universal. In effect, the universal is not so much a concept as a struggle for conceptualization:
"Lacan's 'primordial repression'...is precisely what creates universality as an empty place; and the 'trace of the disavowed in the formal structure that emerges' [Žižek is here referring to Butler's criticisms] is what Lacan calls objet petit a, the remainder of the jouissance within the symbolic order. This very necessity of the primordial repression shows clearly why one should distinguish between the exclusion of the Real that opens up the empty place of the universal and the subsequent hegemonic struggles of different particular contents to occupy this place. (Contingency, 257)