One of Jacques Lacan’s most famous formulations is that what is radically foreclosed in the Symbolic order, returns in the Real order, to result in psychosis. This means “when the Name-of-the-Father as external guarantor of the Symbolic is foreclosed, then delusions may arise in which everyday reality turns into the Real-of-language. External reality ‘to function properly necessitates a symbolic articulation ultimately rooted in the Name-of-the-Father, otherwise it is indeed replaced by phenomena such as auditory hallucinations’ . . . The Name-of-the-Father is, as Other of the Law, the Other of the Other qua Other of the signifiers: when we are confronted with the ‘principle of the law,’ we are thus dealing directly with the very foundation of the universal Name-of-the-Father” (Chiesa, L. . Subjectivity and otherness: A philosophical reading of Lacan, p. 107-111).
The fact that there is an Other “of the (symbolic) Other indicates that the Other as the order of signifiers is guaranteed by another transcendent Other; namely the paternal Law. The Other as Law, the Other of the Other, corresponds to the Name-of-the-Father: this is precisely what allows the resolution of the Oedipus complex, and consequently the detachment of the subject from the disquieting relation he entertained with the mother. The subject is thus enabled actively to enter the intersubjective symbolic field” (ibid.).
“In psychosis, there is no Name-of-the-Father to delimit the field of the subject’s speech. In other words, the foreclosure of the primordial signifier makes the barrier between speech and language collapse. Hence, the universal dimension of the Symbolic into which the psychotic is not able to actively introduce himself is to be regarded as that which “inhabits” and “possesses” him in the guise of the Real-of-language. On the other hand, in nonpsychotic subjects, signifying chains are ordered in speech in the Name-of-the-Father . . . [It] encircles individual speech, and thus allows the active entrance of the subject into the universal dimension of the Symbolic” (ibid.).
Lacan maintained that “psychosis does not correspond to an absence of the Other tout court but, rather, to the effect of the lack of the Name-of-the-Father (as signifier of signifiers) . . . [For inasmuch as] the Other of the signifiers is not regulated by the Other of the Law, the psychotic remains a victim of language; he is ‘spoken’ by it . . . [because in normality it is] the Other of the symbolic Other [who] prevents the subject from being invaded by the Real. Such an invasion occurs, with disastrous consequences, in the case of psychosis” (ibid.).