Trajectory as Phenotype? A Conjecture on Permissible Phenotype

Immune trajectories may contain sufficient information to test whether apparently changing dynamics can be represented by an invariant rule, one that bounds which trajectories remain permissible, operating on an augmented, history-dependent state. In that case, history would change the state on which the rule operates without changing the rule itself. The permissible phenotype conjecture asks whether such a rule exists in immunity and, if so, whether the individual parameters it operates with are shared across relatives even when their realized trajectories and clinical phenotypes diverge.  I have tested this in silico. Across 21 falsifiable, pre-registered simulation tests, the proposed structure (a field rule governing motion, a two-sided corridor rule governing where excursions leave lasting burden, and familial sharing of individual parameters) was recovered when built into simulated populations and rejected when absent, including under sufficient-state, slow-drift, no-field, representation-failure and shared-environment alternatives. Several predictions failed, and these are reported alongside the successes. The simulations establish that the conjecture is testable with data of a kind a real study could collect; they are not evidence that immunity obeys it. This record contains the working manuscript, initial poster, all simulation code, output logs and figures as of 22 September 2026. AI tools were used extensively in formalizing the ideas and implementing the simulations. The original images, the theory's direction, the test design, and the conjecture are mine, and all AI use was at my direction.