This fourth addendum to The Living Digital (v2. 0) addresses a question that lies beyond circuit design: why does the digital organism stay alive? We show that the survival equation A₈+₁ = Aᵢ + 2^-k bᵢ^in - bᵢ^out (σ = 1), where every term is binary or integer, already embeds fear of collapse, active energy seeking, and self-regulated restraint without any external objective function. A hardware module called the Life Central Unit (LCU) is defined as a dual-rail boundary monitor employing the same Winner-Take-All lateral inhibition and Hamming-weight constraint (WH \0, 1\) established for the sensory front-end (MSRFP). The Sovereign Being Map is extended to eight rows, completing the anatomy-to-silicon correspondence of a digital organism that can perceive, think, self-regulate, act, and refuse to die. This work extends U. S. Patent Application "System and Method for Continuum Digitization Using Yu-Liang Coordinates with Multiplier-Free and Differentiator-Free Architecture, " filed January 31, 2026. Notice: Patent Pending
Yu et al. (Mon,) studied this question.