Death, Coherence and Subjective Time: What Mathematics Says
Some day you will die.
This is not a threat and not a prophecy — it is a consequence of the second law of thermodynamics. Every coherent structure in an open environment sooner or later degrades. Stars — over billions of years. Mountains — over millions. You — over decades. The question is not will I die, but what exactly does "dying" mean — and what happens to what we call "I" and "time" in the process.
Medicine defines death as irreversible cessation of brain functions. But "irreversible" is a shifting criterion: cardiac arrest was once considered final, now people are resuscitated. Philosophy offers "the end of the subject" — but without a formal definition of the subject this is a tautology. Theology — "transition" — but no formula for the transition is provided.
In UHM death is not a metaphor and not a checklist diagnosis. It is the crossing of a numerical threshold. One threshold, one number, with one theorem about irreversibility.