The term “structural identity” currently appears across four distinct disciplines with four distinct meanings. In clinical psychology, it maps to structural dissociation—the fragmentation of personality under trauma (van der Hart, Nijenhuis, 2026b; 2026c). This paper presents the formal definition of the discipline, the names and scope of the nine governing laws, the substrate invariance principle, and the relationship between the theoretical architecture and its applied arms. Keywords: structural identity, structural identity sciences, identity architecture, structural dissociation, structural identification, substrate invariance, obligated systems, cognitive due diligence, Monte Carlo validation
Don Gaconnet (Sun,) studied this question.