De Grey's position imagines the possibility (50% chance in next few decades) of a "Methusalarity" a moment in which we begin to reverse some aspects of "aging" , primarily via "damage repair" at such a rate that we are able to repair damage in the body as fast as or faster than that damage is occurring. More concretely defined, it can be thought of as 20-30 years more of expected healthy life at age 60 when anti aging therapies begin.
Among the preamble to this definition, he calls out some important caveats:
- "Aging" is primarily damage accrual
- LEV requires "repairing damage" which is different than delaying or slowing damage
- The age limit is genetically coded, optimized for reproductive health, and any "damage repair" mechanism would still come up against this hard limit.
- The applications and effects of interventions face seemingly insurmountable challenges of "complexity" and furthermore any of the interventions De Grey has proposed have yet to demonstrate an extension of the genetic upper limit.
Topic 1: Damage Repair vs. Genetic Age Maxima
- Brenner's primary challenge in that there is a genetic limit to aging and that there has yet to be any evidence that damage repair advancements will be able to overcome it.
- Secondly, for something like removing "junk" in cells, there is a vast scale issue to overcome and no way to know what sort of complications will emerge, like immune responses.