Identity Fragments - Why Phantoms Persist and Transplants Reject

Phantom limb syndrome and transplant rejection present a symmetry that existing theories do not explain. In phantom limb, substrate is removed yet experiential signatures persist. In transplant rejection, substrate is added yet integration is resisted. The substrate theory of identity—that identity tracks material composition—predicts neither outcome. This paper argues that both phenomena constitute evidence for identity fragments: distributed, substrate-bound signatures of constraint geometry that persist according to their own dynamics rather than tracking material presence or absence. Fragments are higher-order structural invariants instantiated through molecular substrates including antigenic markers, but not reducible to them. The immune system detects foreign fragments and initiates rejection; the nervous system retains a topology of self-fragments that persists despite substrate removal. Both phenomena reflect Eigenbehauptung—the active self-assertion of constraint geometry under perturbation. The asymmetry in temporal dynamics follows from asymmetric detection capacities: systems can detect foreign presence but not self-absence. Falsification conditions are specified. The paper concludes that identity-space geometry is not metaphor but a structure with empirical signatures in how systems respond to substrate loss and substrate addition.