Definition
The invariant biological reference state toward which the system converges when Φ_bio(x) approaches zero. Constant within the biological register. Expression capacity may degrade; x*_bio as the governing reference does not. Pathology reduces the system's ability to reach x*_bio; it does not alter x*_bio itself.
Governing Form
x*_bio = constant ∀t (biological register)
The biological reference state is invariant within its register. x(t) drifts. x*_bio does not.
Role
Biological identity attractor. The terminal condition toward which the system converges when Φ_bio(x) → 0.