Why Aging Isn’t Inevitable
nautil.us
nautil.us
When I was younger, I wanted to live forever. But now I came to believe that dying is actually good, for a similar reasons. As we age and learn, we become experts at many things, but at the cost of flexibility and speed of learning (this is actually expressed in myelin coating of synapses). So we need to have next generation of people starting from scratch, questioning everything, otherwise we would be stuck with the old ways of doing things.
So perhaps aging and death is an evolutionary adaptation, to changing conditions in our environment.
Society might need death, but I still want to live forever.
I also think death is treated too seriously by people believing they're just a bunch of atoms but still thinking of themselves as an entity meaningfully separate from the rest of the world.
I easily figure in the next 100 years we will accept cloning as a replacement for death. Simply duplicate the body, and transfer the brain, maybe throw in some extra gray matter to replenish what is lost through aging. Of course "throw in some extra gray matter" sells the complexity a bit short, but we are definitely on track to accomplish it.
I anticipate never having a 130 year old body. I would just replace mine with a genetically enhanced one at 60, and start over from ~15 (or honestly whatever the earliest age to insert a brain is). Almost anyone should be able to raise the money in ~30 years to pay to have another clone grown.
And from there you can iterate a few generations on first generation tech until we can manipulate the living brain into being able to learn like you are five again, hopefully without the negative side effects present in current brains of that capacity.
Cloning isn't the same thing as "Simply duplicat[ing] the body."
Cloning creates an embryo which turns into a human infant. Then you have to wait 18 years for it to mature before you can transfer the brain.
There's an insurmountable moral barrier to raising a fully conscious child to adulthood and then killing it so you can have its body.
Some commenters down-thread have suggested removing the infant's brain and raising it, without consciousness, in a vat of some sort.
Aside from the obvious difficulty and huge expense of maintaining a fantastical life-supporting "vat" for 18 years, it just simply wouldn't work.
Human beings require social interaction, and consciousness, to survive. An infant deprived of social interaction and environmental stimulation, and the consciousness to experience it obviously, would die. Animals also require physical interaction; our bones and muscles and senses can't develop properly in a vat, so you'd end up with, at best, a pathetic excuse for a body, totally unable to function in any way you'd enjoy, if your clone survived at all (which it wouldn't).
In short, this idea is both morally appalling and biologically ridiculous.
There are also ways to maintain muscles without normal exercise. Direct electro-stimulation is an easy approach.
There is no physical reason you couldn't grow a body without a brain. It's an engineering challenge.
I wasn't talking about you. I was talking about whether a human infant missing most of its brain and deprived of all social interaction, environmental stimulation, and physical activity would thrive and mature normally. It would not.
(Also, just for the record, there are things which aren't possible to do, no matter how many awesome engineers you have.)
>(Also, just for the record, there are things which aren't possible to do, no matter how many awesome engineers you have.)
Yes, like break the laws of physics. Nothing proposed here does that.
If you have to raise your clone by yourself as another human being, who's to say which one of you deserves to keep living?
It all sounds so very nice in theory, but the reality might be that only the very rich and the elite will be able to afford to undergo such procedures, mainly because of the secrecy needed to essentially grow sacrificial human beings to maturity.
But don't worry. There are lots of other ethical concerns to focus on after you get rid of the conscious clone problem.
Arguably, if you're at that level of sophisticated biological manipulation, you're probably better-off simply growing the organs/replacement-parts/cells by themselves.
Read the Commonwealth Saga by Peter F Hamilton
Not sure that we would be able to implement such a rationale solution, but at least it was pretty logical. The novel is essentially about the other grim decisions you have to take to have a constant population.
[0] This was in a book with multiple short stories from Paolo Bacigalupi. I believe this is Pump Six and Other Stories. Most of the novel are rather pessimistic, but at the same times sounds plausible enough to happen. I also recommend The Wind Up Girl from the same author.
This occurs in cell populations - the programmed self-death of cells (apoptosis) becomes corrupted and the individual cell acts selfishly (relative to the organism) and stays alive.
We have a word for this phenomenon and that word is "cancer".
Suspension of apoptosis is necessary, but not sufficient, for cancer. We have plenty of non-cancerous cells that rarely or never undergo apoptosis such as neurons or stem.
The implication that immortality = cancer does not follow.
Indeed, cellular immortality may be cancer when it gets against apoptosis and it's just a natural thing when not. Cancer as well comprises a wider range of anomalous cellular developments that most often does not turn off the apoptosis. The metaphor however was about selfishness, on individual organism and cell level.
I've never understood people who say they'd like to live forever. It just doesn't make any sense to me. The oddest thing is to listen to someone who talks about how it is - not probably or hopefully - going to happen in their lifetime. I once had an acquaintance who spoke of it so seriously that it was religious; he honestly believed (possibly still does) that he will not die.
You have the ones who are so absolutely terrified of death that they desperately grip onto the concept of immortality; a science fiction replacement for an afterlife or reincarnation they do not believe in. (Tangent: Why do so many people reject the idea of open casket funerals. Death is just too horrible to even observe, let alone having to reconcile that it will one day happen to them? "Think of the children" is a common argument, which is bullshit; perhaps such a large number of adults are so fearful exactly because they were never exposed to it.)
You have people who use the idea as a fantasy that someday they will do all the things they want to do, but don't have the time, money, or motivation to do today. This category is depressing, because I don't understand how someone can believe that an extended future would magically fix whatever is holding them back right now.
Then there are those who treat our species like a special little snowflake in the universe. That somehow being sentient with a consciousness is intrinsically deserving of cheating death - self-righteousness at the species level. That science can solve any problem, and not only will it be possible, but that it unequivocally should be done. "I think, therefore I am, and should forever be".
tldr; Death is, at least presently, inevitable. Get over it.
And yeah, I dream of the day I could do more far reaching stuff than what I do to pay the rent.
I see 2 pragmatic reasons for aging: enabling faster biological evolution, and escaping the lower performance/plasticity of older brain. We are at the brink of usefully being able to engineer human DNA and germ line. Once we get there (possibly not in my lifetime) - to the extent brain plasticity/performance can be kept up (and improved) - I see little reason for death through aging.
Anyone who is sufficiently math literate should know that they're very unlikely to live forever. If there's some finite chance you're going to die each year, as you consider longer theoretical lifespans, the probability you'll die gets so close to 1, it's basically a certainty. Anyone who is sufficiently science literate should know that thermodynamics and the heat death of the universe precludes anyone living forever.
All that said, if you offered me a life-span boost to 250, 1000, or a million years, I'd take it!
I think even if we engineer away death, you will still have the psychological structure from the "formative years" -- adolescence to early adulthood-- that sort of fundamentally make you personality-wise.
The songs and movies that gave you emotional experiences, the events that happened, etc. For me and my cohort it would be groups like Nirvana, Pearl Jam, Beck, and movies like Reality Bites and Pulp Fiction. These were the things that spoke to us as we were becoming adults.
It's not that those groups or movies mean much to me nowadays, but I feel that, socially, I am a peer with someone who lived through those years at the same age I did. It's not simply that we share the same cultural references, nor is it just that we happen to be the same age. I think rather that we were formed by the same events at that age and time.
If I live to be 230, I might feel somewhat disconnected from a 200-year-old, even as the age difference becomes relatively smaller and smaller, because that offset of 30 years made for a completely different formative experience. I'd still want to be friends with people who _get_ me.
My grandpa lived into his 90s. It got to the point where the children of his peers were dying. His main thing to do was read the obits and note how he knew that person. He had lots of family and friends, but no one could relate to his stories of old sports games, WWII, etc. etc. He was in good health and will mentally alert, but after my grandma died, it was just a matter of time. He died of a blood infection, no illness or anything.
So even if we can undo aging and death, we still might need to address the developmental process-- tweak it in some direction. Either have eternal formation, or re-formations-- something.
It isn't a great leap to think that if we learn to alter our bodies at the nano/genetic level that we can handle our own evolution.
If we get to a point where large portions of our population are no longer oppressed or in poverty, where horrendous wars are largely a thing of the past, and we are already managing our population and environment in a healthy way -- then I'll be in your camp but right now we're doing exactly none of those things so, uh, no way getting rid of death is a good idea IMO.
What's your evidence that more attrition will create a greater society? If anything, greater longevity of people would allow for the accrual of more knowledge and wisdom. Living longer gives you a better long-term perspective. Give people a direct reason to care about what the environment will be like 150 years from now and maybe they'll care more about the CO2 they're putting out.
but right now
None of this is right now. We're right at the infancy of genetic manipulation. Even with the accelerating rate of technology growth, we won't understand our biology at a genetic level enough to be able to manipulate it in an everyday way for at least 50 to 150 years.
This is a very important concept - and one I would like to help illustrate with a thought experiment:
Think of the most liberal, progressive thinker[1] you can from the 19th century. I don't know ... Karl Marx ? Tolstoy ? Lincoln ? Whomever ...
Now, hold that thought ... and think of the most reactionary, "conservative", bigoted, old-fashioned public figure you can ... Mike Huckabee, perhaps ?
I will now suggest that Mike Huckabee, in almost every imaginable measure, is more progressive and liberal than (whomever you chose in step one). Mike Huckabees wife has worn pants. Mike Huckabee has spoken to a divorced woman in public. Mike Huckabee has probably used birth control.[2]
See how fast that happened ? In less than 200 years, the political window has shifted far enough that the most reactionary, right wing member in 2016 is more liberal and more progressive than the most liberal and progressive figures from the prior period.
How will that work if people from 200 (or 300 or 400) years ago are not only still around, but presumably well funded with vast stores of capital ?
[1] let's limit it to very well known, universally recognized figures...
[2] Ok, I'm not sure about that one, but you get the point ...
http://arxiv.org/abs/1103.4649
"Understanding why we age is a long-lived open problem in evolutionary biology. Aging is prejudicial to the individual and evolutionary forces should prevent it, but many species show signs of senescence as individuals age. Here, I will propose a model for aging based on assumptions that are compatible with evolutionary theory: i) competition is between individuals; ii) there is some degree of locality, so quite often competition will between parents and their progeny; iii) optimal conditions are not stationary, mutation helps each species to keep competitive. When conditions change, a senescent species can drive immortal competitors to extinction. This counter-intuitive result arises from the pruning caused by the death of elder individuals. When there is change and mutation, each generation is slightly better adapted to the new conditions, but some older individuals survive by random chance. Senescence can eliminate those from the genetic pool. Even though individual selection forces always win over group selection ones, it is not exactly the individual that is selected, but its lineage. While senescence damages the individuals and has an evolutionary cost, it has a benefit of its own. It allows each lineage to adapt faster to changing conditions. We age because the world changes."
For a contemporary example, consider the real estate bubble. When the bubble burst and everyone realized how badly the banks had screwed up, what happened? Well, everyone who owned a home worried about losing its value. The banks took some stock off the market to hide it, and all the leadership up to the president vowed to do everything possible to "maintain real estate values", even though the "value" was predicated on sub-prime mortgages that people couldn't actually afford.
In this way, the older generation whose experience is tied to a particular environment exerts its influence in a way that damages the younger population. Being young and inexperienced means being adaptable but naive and inefficient, being old and wise means knowing how things work and a vested interest in keeping them that way.
Otherwise you might have less biodiversity which may make the species less adaptable overtime (and maybe lose to another species with aging).
Now we're on the verge of human assisted gene design vastly outperforming natural evolution.
https://en.wikipedia.org/wiki/Negligible_senescence
So I don't really buy that argument.
Immortality seems to be the case for hydra, for example. (http://www.ncbi.nlm.nih.gov/pubmed/22689361)
Immortality is also observed for flies in late life (http://discovermagazine.com/2001/may/breakdialogue). They have a very high mortality rate at that point, but it doesn't increase further over time. That doesn't seem to be the case for humans, though, based on the very sparse data for people at extreme old age.
https://en.wikiquote.org/wiki/Max_Planck
often summarized as "Science advances one funeral at a time."
(One of the reasons _1984_ is such a nightmare was not it's cruelty and horror, but it's all-too-believable stability, even with human mortality. Orwell's appendix gives a ray of hope, however, when he discusses the fact that human language itself would, in the long run, prevent even that world from continuing indefinitely.)
Makes me think of stackoverflow for some reason.
The big question here is (to which I allude in my comment): How do you control the "resetting" process, so that you wouldn't lose the information that you consider important? I simply don't think there is a good way to do it.
We already have a way to be immortal - have kids and teach them what you know and think is important. Which is an arduous and complicated process; I don't think this "myelin cleaning" or whatever will be any easier.
I don't think I want this reset. It may mean you become entirely different person, or your memories get lost. Let's say you and your wife resets, and forget most memories you have of each other, pretty much why you're together. Or you reset and you become a different person to your kids, and they become different to you.
I personally find either having kids, or teaching (if you can't have kids for whatever reason), a more interesting proposition than some magical procedure that will clean my brain. If anything, it sounds really irresponsible to your future self - kinda like leaving your kids in the forest to take care of themselves.
This already exists in the forms of psychedelic drugs and transcranial magnetic stimulation. There is no memory loss, you just start thinking and feeling about things differently. It can and does lead to divorce and changes in relationships to relatives: http://well.blogs.nytimes.com/2016/03/18/an-experimental-aut...
This is not at all the downside you portray it to be. Many people use these methods to change or leave dysfunctional relationships.
Quite how that'd work economically though, I have no idea.
Moreover, aren't you assuming that we couldn't possibly manage loss of flexibility? Even if most people are inflexible because they've aged, this doesn't prohibit them from having a base level of flexibility and thus find a workaround for whatever limitation you're imagining this imposes.
Software evolves more like the evolution of a species: Small changes over time to adapt the ever changing environment.
It's partly because you are an expert at a unique combination of many things that you have great irreplaceable value. This is threatened by aging diseases even before you die.
Also I don't think that more knowledge makes it harder to learn. This would be true if knowledge was purely about breadth. However it's really about explanatory depth, and depth ultimately wins. For instance, your mind has formed many connections between those aforementioned different fields of expertise, and some of these ideas reach into yet more fields.
The article explains that different organisms exhibit different patterns of aging, when we consider aging as either defined by increases in the probability of death, or decreases in the probability of reproduction.
Taken together with the evolution of species, this implies a plasticity in both the mechanisms and utility of aging - something which is otherwise considered to be a rather solid constant of life.
The takeaway then is that we must 1) widen our definition of aging to accommodate the variety of natural phenomena, and 2) reconsider the intuition that a specific pattern of aging, such as the one found in humans, is necessary for the survival of the organism and/or the species.
If we suppose humans live to around 85 years on average, and rarely if ever die before 65, then there's a big bell curve normal distribution on 85, and what looks like a non-linear exponentially increasing probability of death up to about 80. But that doesn't mean everyone started aging faster at 65, it just means people started dying around 65.
Imagine that you go bowling and throw 20 mph balls on average. The distribution would look similar. Bell curve on a pin dropping at around (say) 5 seconds, but the curve starts at around 4 seconds and ends at 6ish. Does this mean the ball suddenly accelerated at the end? No, in fact the opposite happened, it was slowing down. But the rate of probability that a pin goes down is exponentially increasing from 0-5 seconds.
Not a perfect analogy to aging by any stretch, but am I right that an increase in the probability of death is unrelated to aging - the speed at which we approach death?
If we suppose humans live to around 85 years on average,
and rarely if ever die before 65, then there's a big bell
curve normal distribution on 85, and what looks like a
non-linear exponentially increasing probability of death
up to about 80.
Having an average at some point doesn't mean there's a bell curve around it. The average of a uniform distribution [0-100] may be 50, but there's no bell curve around 50. It's just a uniform distribution all the way through.
The chance of death at a given age is a bell curve.
The chance that I'll die at 150 years old is zero, it is less than the chance that I'll die at age 70. The chance that I'll die by the time I'm 150 is 100%.
So I feel like I still don't understand what you're getting at in your example.
Sadly, we're not even talking about the meat of my point, you got stuck on the uncontroversial preface to my real point. My point was that Nautilus is wrong and maybe being sneaky by saying that aging accelerates near the end of life because the probability of dying is going up. That's not true, and the bowling analogy shows why.
Over time, the probability of pins being knocked over goes up. But you can't conclude that the bowling ball is accelerating. The author made an incorrect conclusion from the data to make his point. It might be intentionally misleading, or it might be a mistake, but it's nonetheless incorrect to suggest that an increase in the probability of death must have been caused by an increase in the rate of aging.
Now, if you want to learn the difference between CDF and PDF, look at the first two pictures in this article: https://en.wikipedia.org/wiki/Normal_distribution
I'm not saying that the PDF of death by age should be a bell curve, I'm stating a fact. It already is a bell curve. Go look at the data. You're trying to argue against reality with logic. You're right, it doesn't have to be a bell curve. But it IS a bell curve.
https://www.longevitas.co.uk/site/images/ELT15.png http://www.aihw.gov.au/uploadedImages/Subjects/Deaths/age-de... http://www.publications.parliament.uk/pa/ld200304/ldselect/l...
Very few people die of old age at 55. Many people die of old age at 80. Very few people die of old age at 100, because there are very few people left. That's a bell curve. Does that make more sense?
There are some problems with the definition. Humans have very high relative probability of death during their first five years, but this quickly declines and then starts to rise again. This means that humans "age" backwards for the first part of their life, which is not particularly intuitive or helpful. However, the definition is helpful in the context of understanding how our aging compares to aging in other animals.
For the first 1/3 - 1/2 of our lives our bodies are building themselves up through growth, but then you hit middle age-ish, hang up the football cleats, and start caring more about your health because "you're not a teenager anymore".
The premise that aging is defined as the probability of death feels artificial, or at least out of line with typical understandings of the word.
Consider the phrase "He looks like he aged 20 years, but it has only been 5 years since I last saw him." Everybody understands this to mean that he looks like his health has declined in 5 years the way most people's health would decline in 20 years.
If you replace "health has declined" with "probability of death has increased", then it means roughly the same thing. It is true that the folk understanding of "health has declined" could be based on several proxies such as skin texture, baldness, etc. I think what the probability of death definition does is bring some precision to what you mean when you say "health has declined".
When my three-year-old nephew ages ten years I would hardly agree that means he's more likely to die, just the opposite. A thirteen-year-old is significantly more fit for survival.
Old people are more likely to die simply because they are in poorer health.
So smokers or people who jump from planes may not be older compared to those who don't. We don't have a single, reliable instrument that can measure individual level aging.
If we find a way to not age and not get cancer, then we have (presumably) evolved.
I agree.
> "Evolution never leads to best-case scenario"
That is not true. It could lead to the most optimal solution.
> Saying "either you age or get cancer" is just... not correct
It is correct until we develop an alternative way that replaces the aging mechanism in cells.
Sure, it is better to neither age nor get cancer.
There is no such thing as "the most optimal solution". Optimality is a human imposition on the world. Fitness functions do not actually exist, they are merely a way for us to conceive of the operation of selection. Evolution is not performing gradient descent.
This comment supposes that aging protects cells against cancer; I think this presumption is based on the antitumor properties of telomeres, which impose the 'Hayflick limit' on cellular division.
It is presumed by humans that this mechanism may have some adaptive role in tumor suppression. However: this is not why it appeared (all eukaryotes have telomeres, even unicellular ones), so any antitumor properties are an ancillary benefit.
It is incorrect to assume it impute reason to evolution. It seems highly likely that aging rests close to the border of selective influence, and it is highly presumptive to imagine it is governed by consequence.
The cell has many ways to combat oncogenesis and when these protections fail, it tries to go into senescence (SIGTERM) or die(SIGKILL).
Nanobots that would replace damaged cells with new non-cancerous ones are not yet here.
[1] http://www.impactaging.com/papers/v2/n7/full/100178.html [2] http://www.nature.com/nrc/journal/v3/n1/full/nrc984.html [3] http://newscenter.lbl.gov/2008/12/02/cellular-senescence/
I did not know that. Is there a reading on this topic you recommend?
If the cell lived (selfishly), it could take down the whole organism with it and not reproduce.
Then we can get into primary aging (think of the SENS list of damage, internal mechanisms like mitochondrial damage and cross-link deposition) versus secondary aging (think of smoking and getting fat, things that increase the pace of damage accumulation), and further complexities after that. But the core definition of aging is very simple, and it is all about dying.
However, aging!=dying since aging can protect the whole organism (as opposed to individual cells) from dying and some would argue that it is there primarily to protect the organism from dying from cancer and for healthy reproduction.
If you age, you get cancer, eventually. Sometimes some other pathology gets you first but everyone is afflicted with every "aging disease" but we seem to only care about which one kills you first.
One of the reasons cells age is to not get cancer. The cells that age can still get cancer! And probably more likely to get cancer than young cells. But less likely than if they didn't go into senescence at all.
Both today's article and yesterdays said something to this effect, which is blatantly wrong. A now-infertile parent affects the survivability of their offspring, possibly positively or negatively. Since their offspring share their genetics, the parent thus is still involved in the natural selection process.
The majority view in the research community is vice versa, that damage -> epigenetic changes. Aging is an accumulation of cell and tissue damage, something that spirals down ever faster as the damage starts to cause damage repair systems to fail. The forms of fundamental damage that cause aging are actually well agreed upon, but there is a lot of argumentation over which are more important and how exactly they cause specific age-related conditions.
How can a field sustain two such diametrically opposed sets of theory? Because while we know the differences between old and young tissue, we still don't have a full accounting of cellular metabolism, and certainly don't have a full map of how a->b->c for all molecular biology at any given time, let alone over the entire course of aging sufficent to explain from start to finish any specific age-related condition.
This is why SENS ("repair the damage, don't try to understand why it causes age-related disease, just fix it and things will become clear one way or another") is so important. We can repair the damage. That is much, much easier and cheaper than trying to understand the full chain of cause and effect.
The next five to ten years should see one or other side proven conclusively wrong. The challenge is that addressing secondary effects in aging can still produce benefits. The water is muddy.
On the damage viewpoint, we have things like senescent cell clearance now under development in companies like Oisin Biotechnologies and UNITY Biotechnology. Clearance extends life in mice. Senescent cells are known to contribute to many age-related diseases.
On the epigenetic alteration side we have things like restoration of youthful GDF11 levels, which improves health in mice by signaling stem cells to go back to work. From the damage viewpoint, those stem cells are in decline as a reaction to damage, and the signaling therapy is an override. From the programmed aging point of view the signaling change is the primary cause.
I think that the most compelling argument against programmed aging and for damage is that some forms of damage cannot be repaired by our biochemistry. Specifically persistent glucosepane cross-links in the extracellular matrix, for example, causing loss of structural properties such as elasticity. Also some of the constituents of liposfusin that builds up in long-lived cells and causes their lysosomes to malfunction. It doesn't matter how youthful your epigenetic patters are, you cannot break them down.
https://www.fightaging.org/archives/2016/01/the-present-stat...
Essentially the few people working on this are still looking for drug candidates, largely based on mining the bacterial world for suitable enzymes to use as a basis. They have bacteria that consume glucosepane, so that's a starting point.
Um, no. They introduced age as probability of dying within that context. Therefore a constant age would produce a population size that shrinks exponentially, but never reaches the zero line, just like with radioactive isotopes' constant decay rate.
It's a log y-axis. A diagonal line downwards is exponential relaxation to 0.
"Survivorship (on a log scale) is depicted by the shaded areas."
Notably, the journal article shades the area underneath the line that is labeled 'survival' in the linked article.
I'll go with physics in this case
However, right now my brain can't remember where I left my wallet, and it's stuck on a loop remembering some stupid kids song, so you may have a point.
In any case, the remembered parts of a millennium may not be complete, but that would be better than a still-incomplete memory of a century.
In the same way as relatively new diseases such as cancer and heart disease have confounded the progress of medicine upon finally mastering the treatment/prevention of infectious disease, what new maladies await us when we "defeat" those and start living well past 100? What does the psychological health of a 100++ year old even look like? Will we _really_ want to live that long, and if so, who dies to make room for the living?
The fact that it also makes you less likely to die is a welcome bonus and the inevitable consequence of medical science.
Then we'll have to choose: do we want newborn babies or really old people?
> Then we'll have to choose: do we want newborn babies or really old people?
I have no idea to what extent we'll defeat aging and extend life. However, it is reasonable to expect that we'll at least manage to go far enough that concerns about population will enter the picture as well as much more strange problems that have never existed but which should be considered.
All I am saying is that there will be other new problems that are uncovered as we continue to extend human life-span.
*There have been cases where a patient could not form new memories but could retain old ones but that does't mean that their brains were "full".
It's remarkable that those stories have some things in common. For example live span decreases after a 'big flood' or another big event.
So some people think that climate also might account for how long we live.
And even today some people claim to be very old: https://en.wikipedia.org/wiki/Longevity_claims
https://en.wikipedia.org/wiki/Paul_Bunyan
PS: Consider, if people are having kids at 12-15, then at 100 someone might be your great, great, great, great, great, grandparent. Why they must be 200 ;0