The schema in the part “Knowledge and truth” in Lacan’s 20th seminar:
In Absolute Recoil chapter 9, Žižek modifies Lacan’s triangular schema: He replaces Φ with S(Ⱥ) and he substitutes S(Ⱥ) with $. What could be the purpose of this modification? I think the purpose of this modification is to neutralize the reality of Φ on the schema.
In his text about the schema, Žižek talks about the triad a, S(Ⱥ), $. According to him, $ is the real thing whereas Φ is just the “phallic signifier” that represents it. It is the same thing as the Master-Signifier S1 which is the “signifier without signified”.
In fact Lacan’s schema places the phallus (Φ) at the most strategic point: Phallus is the reality that is the blind spot of the symbolic order. The symbolization activity of the symbolic order is limited to establishing mediations and bridges between the Imaginary and the Real, so the phallus that is at the immediate Imaginary-Real circuit is the hotspot that the symbolic order cannot access. Say, it’s the point of the unconscious that the consciousness cannot access. But Žižek expels the phallus from this point no questions asked and replaces it with S(Ⱥ). Why does he do this?
According to Žižek, there is no substance concealed behind the symbolic order, or rather the only thing that it conceals is the fact that there is no substance that it conceals, and this fact points to the subject. This means that the only substance is the subject. Thus we experience substance as subject. In his important work The Sublime Object of Ideology, he formulates this as follows:
the substance is the positive, transcendent Essence supposed to be hidden behind the curtain of phenomena; to ‘experience the substance as subject’ means to grasp that the curtain of phenomena conceals above all the fact that there is nothing to conceal, and this ‘nothing’ behind the curtain is the subject.
For the same reason, Žižek says that the only thing that feminine masquerade conceals by evoking a mystery is the fact that ‘it conceals nothing’. This thesis is the reason that Žižek modifies Lacan’s schema to place the signifier of the lack in the Other S(Ⱥ) at the main seat. But there is a serious cost for expelling the phallus from the position of reality and neglecting it.
What Žižek overlooks when he places nothing ($) and less than nothing (a) at the center of his theory of the subject are the three fundamental passions that Lacan defines: The passion of love, the passion of hatred and the passion of ignorance. Lacan places these three passions at the intersections of Symbolic, Imaginary and Real; if we apply it to the triangular schema: The passion of love is based on the truth of S(Ⱥ), the passion of hatred is based on the reality of Φ, the passion of ignorance is based on the semblance of objet a .
When we place the three passions over the schema, we get why S(Ⱥ) must remain on the left: Feminine masquerade looks from the Imaginary towards the Symbolic; it evokes the passion of love by wearing the truth of S(Ⱥ). In parallel to the passion of love instigating symbolic significations, the passion of ignorance is also mobilized: The semblances of objet a that turn towards the Real with a repressive caution provoke desire. The passion of love and ignorance combine to form the fantasy: $ ◊ a.
So can one say that feminine masquerade conceals nothing in fact, like Žižek does? No! However poetic it sounds, one cannot say that feminine masquerade ‘in fact conceals nothing’. At the top right part of the schema, behind the Imaginary, in the unconscious, one finds the passion of hatred and repulsion evoked by Φ that represents the real. So feminine masquerade conceals the hatred, S(Ⱥ) conceals Φ.
In masculine imposture the opposite comes to pass, Φ conceals S(Ⱥ) . For the man, hatred is the source of power for the Master-Signifier S1 that he wears as his power, here phallus becomes the “phallic signifier”. But the reality of phallus concealed by feminine masquerade is not a “phallic signifier”. Phallus, before being a signifier, is the reality that provokes the passion of hatred.
Žižek, by replacing phallus with S(Ⱥ) with a sleight of hand, exhibits an example of feminine masquerade. Thus we turn to his works with our passions of love and ignorance. While intending to experience the substance as subject, we remain unprotected against the hatred that becomes widespread in our relentless age .
 For a detailed examination of this, see “Will is the Power to Endure the Reality of the Symptom”, “Breaking the Fetishistic Mystery and the Third Sex”
 Žižek knows this well: “Φ, the signifier of the phallic power, phallus in its fascinating presence, merely gives body to the impotence/inconsistency of the Other” See “Woman is One of the Names-of-the-Father” Slavoj Žižek
 See “Fütursuz Çağa Karşı Sütur”