6. Life Persists Because Damage Can be Diluted, Repaired, Removed, or Buffered

Every biological function is imperfect and therefore generates by-products, errors, and damage; because the space of possible damage forms is vastly larger than the space of protective/ repair systems, life cannot “know” its full damage composition or evolve dedicated defense for every molecular insult. Protection evolves for the most severe damage forms, and damage may also be partially eliminated by degradation and resynthesis of cellular components. However, the strategy that makes life possible is damage dilution by cell division: as long as the net production rate of deleteriome components does not exceed their dilution, cells can remain viable without having targeted repair for each damage type. This must have been true already for the earliest protocells, and in that sense damage dilution has been the most basic, essential strategy of life (it does not mean it is a dominant strategy in organisms, as additional, often more efficient strategies evolved). In multicellular organisms, this logic is partially preserved through renewal systems, but it also reveals why aging is unavoidable in organisms with nondividing or nonrenewable cells/structures: when dilution is not possible, even mild damages that are individually below the threshold of selection accumulate and eventually overload maintenance, forcing decline.