This paper, the fifth in a series on the philosophy of intimacy and the theory of justice, defends a single thesis with three consequences. The thesis: the subject of an intimate relationship is not a pre-given entity that subsequently enters relation, but is formed and continuously sustained through a specific mechanism, the presence of the other and the practice of joint attention. Part One assembles the theoretical ground, organizing accounts of the relational subject not by school but by the type of constitutive mechanism each proposes: mirror mechanisms (Cooley, Mead, Winnicott, Lacan), triadic mechanisms (joint attention in developmental psychology; Davidson's triangulation), and symbolic mechanisms (Vygotsky, Saussure, Althusser, Butler), with the enactivist correction of theory-of-mind orthodoxy. Part Two argues that the triadic mechanism is the missing middle term between mirror and symbol, offers a layered reconciliation of Lacan and Tomasello, and answers a Levinasian difficulty: in the dyad, the first third party is the shared object itself. Part Three transfers the mechanism to adult intimacy under an explicit no-overclaim discipline, proposing the reflexive triangle: the mature form of intimate joint attention takes the relation itself as its shared object; its limit form is care, where one party holds the triangle open for an other whom incapacity has silenced. Part Four develops the consequences. A critique of the attention economy as a parasite on the triadic structure (the algorithmic feed as a pseudo-shared object) is extended by an analysis of attentional competition across three arenas, showing the contest between the human triangle and its industrial counterfeit to be structurally rigged, and by a regenerative criterion of relational sustainability built on interaction-ritual theory. A further section argues that the symbolic order is the standing distributor of attention, the virtual fourth vertex of every adult triangle, grounding the concepts of attentional alienation (attending executed under a script one cannot appropriate) and attentional autonomy (the couple's joint re-authorship of its law of salience, self-legislation continued by attentional means). A Hohfeldian analysis then shows why there can be no claim-right to attention, and what should stand in its place: an imperfect duty in Kant's register, a virtue of just attention in Murdoch's, and a structural criterion of attentional justice with a distributional clause for the gendered labor of triangle maintenance, argued to be constitutively upstream of epistemic injustice. Finally, carried from fact to norm by twin transcendental and fiduciary bridges, the paper proposes a new category for the theory of justice, constitutive injustice, the systematic degradation not of a subject's holdings or rights but of the conditions of its formation.
W.Q. Huang (Sat,) studied this question.