Intersubjective Dimension
ELI5
The "intersubjective dimension" is just the shared space that opens up between people when they can truly talk to each other — where one person can lie to the other, not just pass along information — and Lacan says psychosis involves losing access to that space.
Definition
The "intersubjective dimension" names the properly symbolic register of the relation between subjects — the dimension in which a subject is constituted not by a mirror-image dyad (the imaginary axis of ego and little other) but by the capacity to use the signifier as such, in its full duplicitous function. The defining mark of this dimension, as Lacan articulates it in Seminar III, is not the transmission of information but the possibility of lure: a subject addresses another precisely as a subject capable of being deceived. This presupposes that both poles of the address are implicated in language — not merely responding to signals but occupying positions within a signifying chain that can mislead, withhold, or misdirect. The intersubjective dimension thus depends structurally on the big Other (the symbolic order, the locus of the signifier) being operative.
In the context of psychosis, the intersubjective dimension serves as a diagnostic foil. When the Name-of-the-Father is foreclosed — when the primordial signifier is rejected into the outer shadows and the symbolic order fails to anchor the subject — the intersubjective dimension collapses. What replaces it is the imaginary "between-I" (the inmixing of subjects), in which the other's initiative appears not as the free use of the signifier but as an enigmatic, mechanical imposition: mental automatism, the felt certainty of being lured without being able to locate the lure within a symbolic exchange. The psychotic subject experiences the Other's speech as coming from the Real rather than from the Symbolic, precisely because the intersubjective dimension — the shared ground of signifier-use and potential deception — has never been fully established.
Place in the corpus
In jacques-lacan-seminar-3, "intersubjective dimension" appears at the pivot of Lacan's structural account of psychosis. The concept is positioned as what psychosis lacks: its failure is explained by the foreclosure of the big Other (the condition of possibility for genuine symbolic exchange), which produces the characteristic phenomena of psychosis — mental automatism, delusion, the feeling that the other's initiative is enigmatic and irresistible — as restitutive, imaginary substitutes. The concept therefore works in direct counterpoint to Foreclosure (the mechanism that voids the symbolic dimension) and Automaton (the compulsive, non-deceptive return of the signifying chain that fills the void). Without the intersubjective dimension, repetition becomes mechanical rather than dialogical.
The concept also clarifies the distinction between the Little Other (the imaginary counterpart, the mirror-double) and the proper symbolic relation between subjects. The intersubjective dimension requires the big Other as its ground: it is the space in which the signifier can be wielded freely — including deceptively — and thus where Inmixing of Subjects (the imaginary "between-I" of psychosis) operates as a pathological substitute. It implicitly draws on the Point de capiton (which anchors signifiers for the neurotic subject) and Psychosis as the clinical structure defined by that anchoring's failure. The concept is best understood as a specification of what the Symbolic order makes possible at the level of intersubjective encounter — a specification visible only in its collapse.
Key formulations
Seminar III · The Psychoses (p.206)
It's characteristic of the intersubjective dimension that you have a subject in the real capable of using the signifier as such, that is, to speak, not so as to inform you, but precisely so as to lure you.
The phrase "not so as to inform you, but precisely so as to lure you" is theoretically loaded because it distinguishes the signifier's properly symbolic function — its capacity for deception, for address, for a duplicity that only a subject can deploy — from the merely informational or signal-like use of signs that would belong to the imaginary or to the automatism of the machine; the word "lure" (leurre) is a Lacanian technical marker indicating that genuine intersubjectivity requires not transparency but the structural possibility of misrecognition sustained by the signifier.
All occurrences
Where it appears in the corpus (1)
-
#01
Seminar III · The Psychoses · Jacques Lacan · p.206
**XIV** > **1**
Theoretical move: The passage argues that psychosis is structured around a failure at the level of the signifier — the exclusion of the big Other — which forces the subject into an imaginary compensation through the "between-I" (inmixing of subjects), explaining the characteristic delusion, mental automatism, and enigmatic assertion of the other's initiative as restitutive responses to the signifier's absence.
It's characteristic of the intersubjective dimension that you have a subject in the real capable of using the signifier as such, that is, to speak, not so as to inform you, but precisely so as to lure you.