Conservation of Existence: Zulfia's Law and Redirection from Time to Lifetime

We propose the Theory of Lifetime Dynamics, a framework treating lifetime as afundamental physical quantity. Every isolated system possesses a conserved Zulfia constantZ that governs its existence. The Law of Existence is Z = η + ∆, where η is LifetimeAlready Lived and ∆ is Lifetime Remaining. Lifetime decays via d∆dt = −k∆2, yielding∆(t) = ∆0/(1 + k∆0t).This framework unifies mortality across biological, quantum, and astrophysical systems,positioning lifetime on equal footing with energy and entropy. The theory is redirectedfrom time to existence, yielding three falsifiable consequences: (i) an Arrow of Existenced∆/dt ≤ 0, (ii) a Power-Persistence uncertainty P × T ∼ Z2, and (iii) no isolated immortalsystem.We further propose, as a conjecture, that gravity may be understood as deviation inthe existence field: mass deviates the Lifetime Remaining ∆ of nearby systems, producinga force Fg = −m∇η without requiring geometric curvature. Black holes emerge naturallyas regions where kg → ∞ and ∆ → 0.Existence itself may be the fundamental field of physics. The application to humanlongevity, via khuman = kgene + kstress, will be addressed in Part II: How Long We CanExist.