New research reveals horse-drawn wagon engineering gains slowing, travel at speeds beyond 12mph unlikely.
Swizec · 10h ago
What about quality of life adjusted life years? I don’t want to live to 100 and be miserable for the last 30
But if you can get me 90 years where I feel like a spring chicken until 89, then that’s just fine.
melling · 30m ago
Yes, the term is “health span” and that’s basically what everyone is talking about every single time you read an article on the subject.
fcatalan · 8h ago
My grandfather lived to 102 and only the last few months were bad, nothing dramatic, just fading away at home, no hospital.
I'd sign up for the same
irrational · 10h ago
Is it just genetic? On my father’s side, people typically live to 100 at a minimum and are perfectly healthy mentally and physically right up till a week or so before they die. My grandmother is 103 and can still lives alone in her house and can walk unassisted, has a memory sharp as anything, and so on. Maybe look at long lived families and figure out what is different about them?
jvanderbot · 9h ago
You're asking if anyone has bothered to study long lived people to determine why they live a long time?
markus_zhang · 10h ago
Wow that’s such a blessing. You are going to have maybe 50% more quality time than many people.
ivape · 10h ago
I think it's just plus or minus 10 years for whatever fate (genetics) had in store for you. That plus or minus being the little we can control (diet/activity).
rhyperior · 9h ago
So much of the modern US diet that’s being exported to the world negatively impacts life and health span. It’s very much controllable, just harder than the default.
ivape · 9h ago
We're also exporting modern US attitudes and psychology (expectations, worldview), which is just an engine for stress. I think overeating is a stress response. Not everyone was a fiend for vanity at the scale we are today.
bigmattystyles · 10h ago
I wonder if as a species we can ever get more comfortable with death. We’re built not to be I realize, and we should never be for those that are young but I feel like we should be ok with living 80ish or more years and then clocking out. That being said, I’m not cool with the idea of dying when good, but when I’m in a major depressive episode, the idea of immortality is terrifying.
jebarker · 10h ago
For me, the sad part about dying isn’t the loss of agency in the world as much as missing the rest of the movie. At 43 I already feel like I’ve mostly realized my potential and I’m just here to raise my kids and then I become a burden. But I really want to know what happens next!
gscott · 9h ago
Your never done raising your kids regardless of how old they are.
sixtyj · 10h ago
In Hollywood, they have 12 types of scenarios. Choose your type of life. Tragedy? Love story? Adventure? Becoming someone?
Life is too short to experience all scenarios that is why we want live longer…
After 60 life sucks. Not always but very often.
So we should use Tim Urban's life-week calendar to being aware how little time we have and not waste it.
kiba · 1h ago
Immortality is a long time to waste on shit that don't matters.
KronisLV · 10h ago
> I feel like we should be ok with living 80ish or more years and then clocking out.
Some people would very much prefer if their consciousness wouldn't have an end date, after which they'll never experience or think anything and will just cease to exist.
bigmattystyles · 10h ago
Maybe, but I feel like most would eventually reach same conclusion as the (majority of) protagonists in the good place…
KronisLV · 9h ago
Perhaps!
Though it would be nice if they had the option of choosing that for themselves, instead of being told that they don't really want long lives and that they should kneel before biology. Whether they're content with 100 years or 100'000 years, that should be up to them.
Or, as others pointed out, if at least whatever amount they're gonna be around for was more dignified and they had a better quality of life, instead of their bodies slowly wasting away.
kiba · 1h ago
That's just terror management of death.[1] That's why we say things like "death gives life meaning".
It's not our species, it's our culture. Anxiety over death leads to consumption, so it's a consumer society's virtue.
echelon · 10h ago
You're not dreaming big enough.
"Accept death, it's beautiful" is cope. It's not beautiful. It's suboptimal horror.
I find it offensive that so many "universe experiencing itself" entities willingly accept a return to dust. Our sun dies, and with it everything on this planet will become metal inclusions in a decaying solar body. You know what doesn't matter in light of that? All other perspectives. Every other conception of death and meaning tends to zero.
I accept death personally. It's 99.9999manynines likely. But I would love to spend my limited energy trying to conquer it or to push forward the societal envelope. Something from earth should conquer the vastness of spacetime and physics.
It's not like how any of us spends our time matters anyway. We're all already dead, geologically timespan speaking.
And who knows. Maybe the gods of the future will reverse simulate the light cone down to your femtosecond neurotransmitter flux. Maybe that's you right now. And maybe they'll pull you forward into an eternity of bliss instead of a read-only memory or sadistic eternal hell simulation. But probably none of those things given how more likely we are to accept doom.
hiAndrewQuinn · 8h ago
>Something from earth should conquer the vastness of spacetime and physics.
I hear this claim often, but I never hear any particular reason for why it's so important compared to e.g. letting Alpha Centauri colonize where the lightcones overlap.
saulpw · 9h ago
Consider that some people have gotten past it, and that it's not a "cope". Enlightenment is real even if it horrifies you because you aren't there yet.
username135 · 48m ago
I've visited that space before. Its greatest tragedy isn't the ideas it births, but how seductive the nihilism becomes. You recognize its smallness once you've outgrown it.
kiba · 56m ago
Sure if it helps you sleep at night, but it also leads to a lot of unhealthy behaviors such as drinking, smoking, and not taking care of yourself.
tick_tock_tick · 51m ago
Enlightenment is cope. It's literally coping so hard you enjoy the cope itself.
czhu12 · 10h ago
I don’t want to be that guy but isn’t this kind of an obvious result? The main claim is that life expectancy improvements in the past century are mostly due to decreases in childhood mortality.
During the Roman period, the average life expectancy was only 22-25 years old because so many babies were dying prematurely.
If you could make it past the age of 10, then you were expected to make it to about 50, which almost doubles life expectancy.
That's 100% on the mark. Infants aren't dying anymore.
Real longevity is hard science and we're still at the punch card phase of biology.
Wake me up when we can make headless, full body monoclonal donors for human head transplants. Antigen free / HLA neutral so immunosuppressants are a thing of the past. That'll cure every cancer except brain and blood, cure every other injury, and increase health span of everything but the brain.
The tough problems:
- religious ick and luddite ick
- artificial gestation
- deactivating the brain stem without impacting development
- keeping the body physiologically active and developmentally normative
- head transplants that preserve spinal cord function
- lots of other ancillary issues with changes to pulmonary and immune flux.
markus_zhang · 10h ago
I think it’s fine. When I get older I’m more intrigued whether there is an afterlife, whatever it is.
qgin · 30m ago
When you have general anesthesia, you experience nothing, not even the vague sense of time passing like when sleeping, it's just an edit in time. You basically don't exist when you're under general anesthesia.
If a little propofol in my brain can make me not exist, I'm pretty sure when I don't even have a brain I will definitely not exist.
latexr · 9h ago
> I’m more intrigued whether there is an afterlife
That’s only intriguing if the answer is “yes”. Otherwise it doesn’t matter.
markus_zhang · 7h ago
Yeah the if is where the intriguing is.
elicash · 10h ago
My understanding was that life expectancy has been declining for like a while, not merely slowing in gains -- first because of opioids and then because of COVID.
Edit: In the U.S. that is.
hollerith · 9h ago
>life expectancy has been declining
Only in the US whereas the OP "analyzed life expectancy for 23 high-income and low-mortality countries".
No comments yet
DustinBrett · 10h ago
That kind of thinking is fuel for the AI accelerationists
ziofill · 16m ago
Oh, crap
adastra22 · 10h ago
There is no physical/chemical/biological reason you can’t live indefinitely with the health and vitality of a 25-35 year old. Aging isn’t a law of nature.
VincentEvans · 10h ago
You haven’t quite come to grips with mortality, I think.
qgin · 22m ago
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.
JumpCrisscross · 9h ago
> 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.
anigbrowl · 5h ago
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.
danielmarkbruce · 30m ago
The person just said aging isn't a law of physics. They are right, you are the fool here.
lossolo · 9h ago
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.
hallole · 7h ago
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.
kingstnap · 9h ago
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.
lossolo · 8h ago
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.
JumpCrisscross · 9h ago
> no physical/chemical/biological reason you can’t live indefinitely with the health and vitality of a 25-35 year old
We don’t know this. We know of no creatures as biologically complex as humans that demonstrate biological immortality. That might be because nature never bothered. It might be because it can’t.
But you are generally correct: we have strong evidence healthspan-increasing interventions are not only possible, but proximate. That research could move faster with more funding, particularly from the public, since if we relinquish this funding to the rich it will not prioritize treatments which may be slightly less effective but much cheaper and thus broadly applicable.
adastra22 · 5h ago
Two points:
(1) Yes we do have an example: us. Why is a baby’s cells young and healthy, and not the age of the parents? Dormant eggs are not the answer as you’d still get accumulating damage over time. Turns out there are mechanisms for cellular reprogramming which rejuvenates cells. There are mechanisms for making ages cells indistinguishable from young cells. We just haven’t fully harnessed this capability on therapeutics yet.
(2) The deeper point is one of logical necessity. No bird flies faster than the speed of sound, yet that doesn’t work as an argument for the impossibility of the SR-71 or Concorde. No physical law prevents restoring tissue to healthy young state. We just haven’t developed the tools to do so (yet).
JumpCrisscross · 3h ago
> No physical law prevents restoring tissue to healthy young state. We just haven’t developed the tools to do so (yet)
You’re speculating too far beyond what we know to speak so definitively. Plenty of biology and even thermodynamics suggests there may be limits. That doesn’t prove they exist. But it’s in the same category as saying there are no know physics which prohibit time travel or transcending the human condition into a state of pure consciousness. Like, sure, there aren’t, but to use your analogy, ancient Romans didn’t know about the speed of light.
SoftTalker · 10h ago
Odd then that every living thing ages and eventually dies?
danielmarkbruce · 28m ago
but we haven't really even tried...
conception · 10h ago
This is not true and easily countered by any sort of investigation.
Lobsters, flatworms, immortal jellyfish and hydras are all believed to be immortal.
In fact we know how to live forever, control our telomeres. We know it works because cancer exists. We just can’t control it but controlled cancer is effectively immortality.
alextheparrot · 10h ago
Cancer is a parasitism that kills the host (or the host dies from other causes and it is not self-sufficient). Just because something is defined by uncontrolled self-replication doesn’t mean it is stable to live forever (Which is as much a comment on homeostasis as self-renewal)
jebarker · 10h ago
Is it true that those creatures are believed to be immortal or we’ve just never seen one die of natural causes?
JumpCrisscross · 9h ago
[EDIT: Biologically] immortal doesn’t mean indestructible. It just means they don’t age.
Lobsters aren’t truly biologically immortal. They “continue to grow throughout their lives,” with “increasing amounts of energy” being needed to mount ans they grow larger [1]. “Eventually the cost is too high and lobsters can die from exhaustion.” (That said, if our cells aged like lobsters we’d live something like thousands of healthy years.)
For true biological immortality, look to some jellyfish [2]. You literally can’t tell if a cell is taken from an old or juvenile.
> Immortal doesn’t mean indestructible. It just means they don’t age.
Technically “immortal” means “never dying”, it has nothing to do with age. You could be unable to die but continue to age and become ever more decrepit (although the Oxford dictionary does list “never decaying” in its definition), for sure there’s a sci-fi short story about that out there.
The mentioned creatures all age, they do get older, it just so happens their bodies don’t deteriorate, or they do but regenerate.
JumpCrisscross · 9h ago
> Technically “immortal” means “never dying”, it has nothing to do with age
Hence my use of the term biologically immortal.
> mentioned creatures all age, they do get older, it just so happens their bodies don’t deteriorate
Were you really confused that OP was talking about stopping physical time?
latexr · 9h ago
> Hence my use of the term biologically immortal.
That’s the second paragraph. I was specifically addressing only the first (the one I quoted). In that one you seem to be saying that “immortal means not aging”. That’s the only part of your post I wanted to address, the rest was very clear.
JumpCrisscross · 9h ago
Got it, thank you. Edited for clarity.
pests · 10h ago
I believe one listed converts back to a polyp form under bad conditions and just has another go.
Qem · 9h ago
> Lobsters, flatworms, immortal jellyfish and hydras are all believed to be immortal.
What is the oldest known living individual for each of these species, and for how long are they alive?
JumpCrisscross · 9h ago
> What is the oldest known living individual for each of these species, and for how long are they alive?
For the jellyfish, we don’t know. Their cells are indifferentiable by age and they’re bastards to study, with only one scientist in Kyoto having managed to culture them [1].
But that doesn't mean that it will be economically feasible.
BriggyDwiggs42 · 42m ago
The cost of tech tends to fall as a rule. Why wouldn’t it eventually become feasible?
tristramb · 10h ago
And I wouldn't expect it to be, given that were are the product of billions of years of an evolutionary process that has relied on 'scrap and rebuild from scratch' as a mechanism to control errors.
tokai · 10h ago
It out of my wheelhouse but isn't telomeres a physical/chemical/biological reason we can't live forever?
JumpCrisscross · 9h ago
> isn't telomeres a physical/chemical/biological reason we can't live forever?
It’s one component, but not the only reason [1].
Naked mole rats’ telomeres do “not shorten with age but rather showed a mild elongation” [2]. They are long lived, for rodents, and don’t degrade into balls of cancer [3]. They nevertheless age.
I believe the argument would go "there's no fundamental reason we can't fix telomeres".
chpatrick · 10h ago
Isn't the reason cancer? Eventually the DNA copying errors add up.
andrewflnr · 6h ago
There are a handful of animals, mammals even, that essentially don't get cancer (some/all large whales and naked mole rats IIRC). So that might be solvable other ways.
sodality2 · 9h ago
Cancer is not fundamentally unsolvable (AFAIK?). This is a tough question to answer though. Can we prove cancer to be solvable without solving it?
adastra22 · 5h ago
You also fix the copying errors.
__turbobrew__ · 10h ago
We need ECC for DNA, I could probably use a deep scrub.
tietjens · 10h ago
Interesting claim. Care to state your age?
adastra22 · 5h ago
Why is that relevant.
wslh · 10h ago
Are you watching "Alien: Earth" series?
goeiedaggoeie · 10h ago
entropy comes for us all
echelon · 9h ago
Oxygen is on oxidizer and evolution only needed to keep our gene carriers optimized to reproduce within our fitness landscape trough.
croes · 10h ago
>There is no physical/chemical/biological reason you can’t live indefinitely
Given that that the universe hasn't an indefinite life span there is at least physical reason why we can't live indefinitely.
c22 · 9h ago
When is the universe definitely going to die?
croes · 9h ago
If the if is certain the when doesn’t matter.
c22 · 6h ago
How certain could anyone possibly be on this subject? I can agree it likely doesn't matter to us either way.
close04 · 10h ago
Physical/chemical maybe not, but biologically there might be strong reasons to not allow a complex organism to live forever. Evolution might be accounting for a lot of the reasons leading to the death of the individual organism. For one it would stimulate evolution itself and also alleviate the inevitable resource pressure.
A species that lives forever must adjust to reproduce relatively slowly to not overwhelm the local environment. A species that lives short lives will reproduce at much higher rates. So at any time the fewer “immortal” individuals would be vulnerable to competition from the many “mortals”, or to predators.
Humans are a special case because we don’t operate only on biological imperatives so you could make immortal humans but with implications we can’t even think of now. Maybe our limitation will not be biological but societal.
adastra22 · 5h ago
You are mixing up evolutionary incentives with real chemistry-driven biological constraints. The base incentives of reproduction-driven natural selection may make aging inevitable under natural selection, but that says nothing of artificial selection or bioengineering.
dyauspitr · 10h ago
Life extension will happen. It’s really just a matter of time with the upper bound being no later than a century from now in my opinion.
ALittleLight · 10h ago
This looks pretty trivial. Obviously modern gains in life expectancy were from removing things that killed us in early age. This says nothing about future gains in life expectancy which may come from biological/medical interventions that reduce senescence.
amelius · 10h ago
Trump administration isn't helping either ...
cronelius · 10h ago
bryan johnson has entered the chat
meindnoch · 10h ago
I have this feeling he's going to die way earlier than he would have if he just lived a normal life.
elitan · 10h ago
I have the opposite feeling.
AstroBen · 10h ago
I mean he's just marketing eating well, sleeping and exercising.. how on earth would that make him die way earlier?
rhyperior · 9h ago
The number of supplements and treatments he’s taking are probably too much, and some are quite experimental. He’s definitely rolling some dice.
It is ironic that many of the people obsessed with life extension are also those deeply involved in creating systems that deliberately waste the time we already do have, via addictive algorithms, clickbait content, unnecessary consumerism, etc.
“It is not that we have a short time to live, but that we waste a lot of it. Life is long enough, and a sufficiently generous amount has been given to us for the highest achievements if it were all well invested. But when it is wasted in heedless luxury and spent on no good activity, we are forced at last by death’s final constraint to realize that it has passed away before we knew it was passing. So it is: we are not given a short life but we make it short, and we are not ill-supplied but wasteful of it… Life is long if you know how to use it.”
- Seneca
BriggyDwiggs42 · 43m ago
Well sure but we waste it for circumstantial reasons. Wisdom is scarce by definition. Denying people a second chance because they messed up with literally zero information isn’t something we should condone.
latexr · 9h ago
I was already familiar with Seneca and that quote, but reading it now it sounds condescending. Of course a stoic would say that. Even if we concede that most people “waste” most of life, claiming it is “long enough” and we have a “sufficiently generous amount of it” is just opinion and not something to be prescribed to others. “Long enough” for what? For what Seneca enjoyed, maybe, he had nothing to do and only a fraction of the available world knowledge.
Nowadays one lifetime isn’t even enough to read every book one would find interesting, and reading might be your favourite thing in the world that you do at literally ever opportunity. Long enough… Pft… Seneca clearly wasn’t familiar with the essentially infinite world of fan fiction. He surely would’ve judged it if he had.
Just to drive the point home: The comment is tongue in cheek. I agree with your first paragraph.
But if you can get me 90 years where I feel like a spring chicken until 89, then that’s just fine.
I'd sign up for the same
After 60 life sucks. Not always but very often.
So we should use Tim Urban's life-week calendar to being aware how little time we have and not waste it.
Some people would very much prefer if their consciousness wouldn't have an end date, after which they'll never experience or think anything and will just cease to exist.
Though it would be nice if they had the option of choosing that for themselves, instead of being told that they don't really want long lives and that they should kneel before biology. Whether they're content with 100 years or 100'000 years, that should be up to them.
Or, as others pointed out, if at least whatever amount they're gonna be around for was more dignified and they had a better quality of life, instead of their bodies slowly wasting away.
Utter bollocks.
1. https://en.wikipedia.org/wiki/Terror_management_theory
Psychedelics for everyone!
https://hms.harvard.edu/news/how-psychedelic-drugs-can-help-...
https://www.vice.com/en/article/taking-psychedelics-helps-pe...
"Accept death, it's beautiful" is cope. It's not beautiful. It's suboptimal horror.
I find it offensive that so many "universe experiencing itself" entities willingly accept a return to dust. Our sun dies, and with it everything on this planet will become metal inclusions in a decaying solar body. You know what doesn't matter in light of that? All other perspectives. Every other conception of death and meaning tends to zero.
I accept death personally. It's 99.9999manynines likely. But I would love to spend my limited energy trying to conquer it or to push forward the societal envelope. Something from earth should conquer the vastness of spacetime and physics.
It's not like how any of us spends our time matters anyway. We're all already dead, geologically timespan speaking.
And who knows. Maybe the gods of the future will reverse simulate the light cone down to your femtosecond neurotransmitter flux. Maybe that's you right now. And maybe they'll pull you forward into an eternity of bliss instead of a read-only memory or sadistic eternal hell simulation. But probably none of those things given how more likely we are to accept doom.
I hear this claim often, but I never hear any particular reason for why it's so important compared to e.g. letting Alpha Centauri colonize where the lightcones overlap.
During the Roman period, the average life expectancy was only 22-25 years old because so many babies were dying prematurely.
If you could make it past the age of 10, then you were expected to make it to about 50, which almost doubles life expectancy.
https://en.m.wikipedia.org/wiki/Demography_of_the_Roman_Empi...
Real longevity is hard science and we're still at the punch card phase of biology.
Wake me up when we can make headless, full body monoclonal donors for human head transplants. Antigen free / HLA neutral so immunosuppressants are a thing of the past. That'll cure every cancer except brain and blood, cure every other injury, and increase health span of everything but the brain.
The tough problems:
- religious ick and luddite ick
- artificial gestation
- deactivating the brain stem without impacting development
- keeping the body physiologically active and developmentally normative
- head transplants that preserve spinal cord function
- lots of other ancillary issues with changes to pulmonary and immune flux.
If a little propofol in my brain can make me not exist, I'm pretty sure when I don't even have a brain I will definitely not exist.
That’s only intriguing if the answer is “yes”. Otherwise it doesn’t matter.
Edit: In the U.S. that is.
Only in the US whereas the OP "analyzed life expectancy for 23 high-income and low-mortality countries".
No comments yet
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.
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 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.
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.
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.
We don’t know this. We know of no creatures as biologically complex as humans that demonstrate biological immortality. That might be because nature never bothered. It might be because it can’t.
But you are generally correct: we have strong evidence healthspan-increasing interventions are not only possible, but proximate. That research could move faster with more funding, particularly from the public, since if we relinquish this funding to the rich it will not prioritize treatments which may be slightly less effective but much cheaper and thus broadly applicable.
(1) Yes we do have an example: us. Why is a baby’s cells young and healthy, and not the age of the parents? Dormant eggs are not the answer as you’d still get accumulating damage over time. Turns out there are mechanisms for cellular reprogramming which rejuvenates cells. There are mechanisms for making ages cells indistinguishable from young cells. We just haven’t fully harnessed this capability on therapeutics yet.
(2) The deeper point is one of logical necessity. No bird flies faster than the speed of sound, yet that doesn’t work as an argument for the impossibility of the SR-71 or Concorde. No physical law prevents restoring tissue to healthy young state. We just haven’t developed the tools to do so (yet).
You’re speculating too far beyond what we know to speak so definitively. Plenty of biology and even thermodynamics suggests there may be limits. That doesn’t prove they exist. But it’s in the same category as saying there are no know physics which prohibit time travel or transcending the human condition into a state of pure consciousness. Like, sure, there aren’t, but to use your analogy, ancient Romans didn’t know about the speed of light.
In fact we know how to live forever, control our telomeres. We know it works because cancer exists. We just can’t control it but controlled cancer is effectively immortality.
Lobsters aren’t truly biologically immortal. They “continue to grow throughout their lives,” with “increasing amounts of energy” being needed to mount ans they grow larger [1]. “Eventually the cost is too high and lobsters can die from exhaustion.” (That said, if our cells aged like lobsters we’d live something like thousands of healthy years.)
For true biological immortality, look to some jellyfish [2]. You literally can’t tell if a cell is taken from an old or juvenile.
[1] https://www.nhm.ac.uk/discover/are-lobsters-immortal.html
[2] https://www.nhm.ac.uk/discover/immortal-jellyfish-secret-to-...
Technically “immortal” means “never dying”, it has nothing to do with age. You could be unable to die but continue to age and become ever more decrepit (although the Oxford dictionary does list “never decaying” in its definition), for sure there’s a sci-fi short story about that out there.
The mentioned creatures all age, they do get older, it just so happens their bodies don’t deteriorate, or they do but regenerate.
Hence my use of the term biologically immortal.
> mentioned creatures all age, they do get older, it just so happens their bodies don’t deteriorate
Were you really confused that OP was talking about stopping physical time?
That’s the second paragraph. I was specifically addressing only the first (the one I quoted). In that one you seem to be saying that “immortal means not aging”. That’s the only part of your post I wanted to address, the rest was very clear.
What is the oldest known living individual for each of these species, and for how long are they alive?
For the jellyfish, we don’t know. Their cells are indifferentiable by age and they’re bastards to study, with only one scientist in Kyoto having managed to culture them [1].
[1] https://en.m.wikipedia.org/wiki/Turritopsis_dohrnii
It’s one component, but not the only reason [1].
Naked mole rats’ telomeres do “not shorten with age but rather showed a mild elongation” [2]. They are long lived, for rodents, and don’t degrade into balls of cancer [3]. They nevertheless age.
[1] https://en.m.wikipedia.org/wiki/Senescence#Theories_of_aging
[2] https://pmc.ncbi.nlm.nih.gov/articles/PMC6651551/
[3] https://www.science.org/doi/10.1126/sciadv.abe0174
Given that that the universe hasn't an indefinite life span there is at least physical reason why we can't live indefinitely.
A species that lives forever must adjust to reproduce relatively slowly to not overwhelm the local environment. A species that lives short lives will reproduce at much higher rates. So at any time the fewer “immortal” individuals would be vulnerable to competition from the many “mortals”, or to predators.
Humans are a special case because we don’t operate only on biological imperatives so you could make immortal humans but with implications we can’t even think of now. Maybe our limitation will not be biological but societal.
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“It is not that we have a short time to live, but that we waste a lot of it. Life is long enough, and a sufficiently generous amount has been given to us for the highest achievements if it were all well invested. But when it is wasted in heedless luxury and spent on no good activity, we are forced at last by death’s final constraint to realize that it has passed away before we knew it was passing. So it is: we are not given a short life but we make it short, and we are not ill-supplied but wasteful of it… Life is long if you know how to use it.”
- Seneca
Nowadays one lifetime isn’t even enough to read every book one would find interesting, and reading might be your favourite thing in the world that you do at literally ever opportunity. Long enough… Pft… Seneca clearly wasn’t familiar with the essentially infinite world of fan fiction. He surely would’ve judged it if he had.
Just to drive the point home: The comment is tongue in cheek. I agree with your first paragraph.