New research reveals longevity gains slowing, life expectancy of 100 unlikely

You haven’t quite come to grips with mortality, I think.

> You haven’t quite come to grips with mortality

This is unfair, and akin to branding anyone who takes medicine as being unhinged.

There is evidence we can extend our health spans. By how much and how are open questions. And if we can actually stop aging, versus slow it down, has not been demonstrated. Some people engage with this unhealthily, just as many terminally-ill cancer patients unhealthily engage with long-shot treatment options. That doesn’t make everyone taking those treatments delusional.

I’d hope we more mature as a society than decrying real medical research that could materially increase our health spans because they’re heretical.

I think OP is not entirely incorrect. Reproductive cells undergo processes like epigenetic reprogramming, which basically strips away many of the chemical marks (like DNA methylation patterns) that accumulate with age. That’s one of the reasons babies don’t start with the cellular age of their parents. Researchers can take adult cells, reprogram them back to an embryonic like state using Yamanaka factors (a set of four genes) effectively erasing their biological age.

I think scientists currently are testing ways to "partially" reprogram cells to make them younger while keeping their function. Early studies in mice have shown some reversal of aging signs.

Seems like an engineering problem more than an absolute limitation.

DNA damage inevitably accumulates. The big reason children are younger than their parents DNA wise is because the parents' DNA undergo random recombination to create something that is the mixture of the two.

This doesn't help overall. Mixing two roughly equally broken things just yields the mean of the two. But the trick is that roughly 60 to 70% of conceptions will not survive to birth. This rejection sampling is ultimately what makes children younger.

If you had a population of single cells that didn't undergo this rejection sampling at some point, entropy and Muller's ratchet would actually age the entire population and kill it.

You are right that DNA damage inevitably accumulates and that selection (including miscarriages) weeds out embryos with severe defects but that doesn’t fully explain why a newborn’s biological age is near zero.

What scientists usually mean by "cellular age" isn’t mutation load, it’s the epigenetic and functional state of cells. During gametogenesis and early embryonic development DNA undergoes extensive repair, telomere maintenance and global epigenetic reprogramming that wipes and rewrites methylation patterns. This resets the cellular "clock" even though some mutations are passed on.

So while mutation load drifts slightly each generation, the reason babies start biologically young is this large scale reprogramming. That’s also why researchers are trying to mimic this process in adult cells (Yamanaka factors etc) to reverse aspects of aging.

Fully agree! I don't think life is much more than a sort of chemical engineering, "designed" with the "purpose" of self-replication. Our engineer, natural selection, didn't have "healthspan" in mind; insofar as we are human-making machines, we're pretty well built. I fail to see any reason that necessarily precludes a retooling of our internal machinery to accomplish our desires, not nature's.

It's the 'indefinite' part that I react negatively to. I don't have a good impression of people who are obsessed with abolishing death, as opposed to your example of maximizing quality of life (or minimizing illness) without getting too hung up on overall age.

The person just said aging isn't a law of physics. They are right, you are the fool here.

Social shaming is a big way humans deal with unchangeable things. They impose a cost for anyone expressing a desire for that thing to be different.

And it makes sense, really. You can't have a functioning society if everyone is running around freaking out about death all the time.

But we're entering a weird time where we might actually be able to add more good years to our lives. One of the steps towards getting there is being a little more okay with people seriously exploring these ideas.

I don't see the point in doing that

Actually they said: "Aging isn’t a law of nature." But it kind of is. Almost all biological organisms age and the ones that don't are much simpler than us. That's not to mention entropy which is both a law of physics and dictates an inescapable form of aging for the universe as a whole.

They also said there isn't a physical reason, that is often meant to mean "it isn't a law of physics".

The fact that something happens doesn't mean it's a law of anything. Cars didn't exist before we built them - no law of "no cars". People died of TB before we had a cure - no law of "TB". Same for various types of cancer.

In practice when someone says "live forever", they don't mean to imply they'll live the 10^100 (or whatever the guestimates are) years to the end of the universe. They mean they'll stop aging in the sense that we do now. Maybe we could live to 10,000 or 50,000 or whatever. You can always get hit by a bus, or get some strange disease from a bat, or whatever.

If mortality is just a tradition and you're the first to realize you needn't acquiesce, sure.

If not, the point in doing that is the enormous amount of suffering you create while thrashing against an inevitability.

That is not to say you should take naps and wait patiently for death, but it's a line to walk.

> If not, the point in doing that is the enormous amount of suffering you create while thrashing against an inevitability.

This is absurd. Of course mortality is inevitable -- eternity is a very long time -- but working to increase lifespan, prolong one's youth and vigor, and delay the inevitable doesn't cause an "enormous amount of suffering" (far less than the diseases of aging cause) and it's unfair to characterize it as "thrashing" when it can be approached in ways which are thoughtful and reasonable.

More over, babies can clearly grow from limited cells to "young" versions of fully differentiated human tissues. Which means from some initial stock, you can replace the vast majority of the bodies cells with younger versions - i.e. with plausible, attainable technology we would generally expect to be able to grow immunologically identical replacement organs and major tissues. That definitely is an engineering problem, more then anything else.

The only truly troubling one is the brain, and we're very much not sure if it actually is one or for example, suffers degradation from the degradation of the body its attached to - likely both - but we also know that the brain is not a static structure, and so replacement or rejuvenation of key systems would definitely be possible (certainly finding any way to protect the small blood vessels in the brain would greatly help with dementia).

You aren't wrong. I was replying to a flippant declaration "I don't see the point [in coming to grips with mortality]", which is quite different from your nuanced reply.

I tried to convey that I'm not saying "this is as good as it gets and it's wrong to try for longer life". Your "thoughtful and reasonable" approach was exactly what I had in mind.

What I say leads to suffering arises from denying that mortality is inevitable and tarring those who say otherwise as defeatists. Death is another part of life, as you acknowledged. It unnerves me to see denying that truth cast as a virtue.