The speculation is very convincing, it goes like this: 1) Senescence is a collection of symptoms caused by incomplete repair mechanisms allowing damage to build

The speculation is very convincing, it goes like this: 1) Senescence is a collection of symptoms caused by incomplete repair mechanisms allowing damage to build up, 2) some level of damage has very little ill effects (e.g. the amount you've collected on your 25th birthday), and 3) there are interventions that stop the accumulation of damage or even reverse it. I believe currently only 3) is a bit controversial, but since there are biologically immortal organisms I find it plausible that it's possible.