Identity as a Coherence Interface_ A Structural Theory of Selfhood in Biological Phase Systems

AbstractHuman self-understanding has almost always been framed in narrative terms: stories, traits, beliefs, motives, and psychological profiles. At the same time, biology operates through rhythmic phase-coherence across cardiac, neural, autonomic, and circadian systems. This paper argues that the gap between these two domains — narrative representation and phase-based dynamics — is the source of a millennia-long modeling error about identity. I propose that identity is not an essence or a story but a coherence interface: a regulatory mechanism that stabilizes behavior in a biological phase system that lacks introspective access to its own invariants. The paper develops this claim in four steps. First, it characterizes the organism as a coherence-bound ensemble of rhythms subject to lawful drift. Second, it shows that perception cannot represent phase, drift, or invariants, and therefore compensates with narratives. Third, it analyzes ego, belief, delusion, and meaning as adaptive illusion architectures that maintain stability under substrate blindness. Fourth, it formulates an identity law: identity is the regulatory coherence interface of a biological phase system with invariant-blind perception, and derives empirical predictions about drift signatures, delusion, personality, and structural cognition. The result is a substrate-level definition of identity that unifies insights from neuroscience, psychology, dynamical systems, and philosophy of mind. Identity becomes measurable and law-bound: not the story a system tells about itself, but the mechanism that makes stories necessary.