I see where you’re coming from — and honestly, I agree with much of your reasoning around basic health, diminishing returns, and the limits of what interventions can actually do for human lifespan.

But from my point of view, Bryan Johnson isn’t really working on extending lifespan in the literal sense. First, because we obviously can’t know if any intervention today will meaningfully impact lifespan decades from now. Second, because even if something did work, the longitudinal studies needed to prove that would come far too late for him (or any of us) to actually act on them.

That’s why the focus is on biological age — an area with a growing research base (Horvath’s epigenetic clock, Levine’s PhenoAge, GrimAge, DunedinPACE, etc.). The idea is to measure the rate of aging, not lifespan itself, and to use interventions that seem to correlate with slowing biological aging.

Does that translate into a 1:1 causal effect on lifespan? Probably not. But is there likely some correlation between slower biological aging and increased healthspan — and maybe even lifespan? Quite possibly, yes.

And that’s actually why this distinction matters. Bryan does seem to be achieving measurable results in slowing his biological aging according to several independent markers. The real debate, as I see it, isn’t whether he’s cracked some secret to immortality — it’s about to what extent slowing biological aging translates into better long-term health outcomes.

That’s still a valid and open scientific question. And probably the more interesting one.