
Why Aging Isn’t Inevitable - dnetesn
http://nautil.us/issue/36/aging/why-aging-isnt-inevitable
======
js8
A more interesting question would be why software programs, or databases, age
and die. At some point, their own size and complexity will make them hard to
change, and they will be left to slowly die.

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.

~~~
fnbr
You're right, of course. However, I am extremely selfish, and while I agree
with you, I can't help but think "yes, but not me."

Society might need death, but I still want to live forever.

~~~
_yosefk
I'm selfish enough, but I'm not sure how enjoyable it would be once I reach
130, not to mention 1300, on the theory that even if much of the physical
aging problem is solved, much of the mental aging problem will remain, and the
same things making me increasingly mentally inflexible will make it all
increasingly less fun.

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.

~~~
zanny
We have had successful cryonic restoration of brain tissue in rabbits? I
believe, and have also had successful brain transplants of mice.

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.

~~~
WaltPurvis
> in the next 100 years we will accept cloning as a replacement for death.
> Simply duplicate the body, and transfer the brain

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.

~~~
wyager
The human body does not literally require social interaction to continue
operating. That's just silly.

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.

~~~
WaltPurvis
>The human body does not literally require social interaction to continue
operating. That's just silly.

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.)

~~~
wyager
Obviously a body with no brain wouldn't do great. That's why you put the a
brain in before you start using the body.

>(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.

------
jsnathan
Going to try to summarize a bit.

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.

------
dahart
I'm a little troubled by the argument that an increase in the probability of
death signifies or is equivalent to an increase in the rate of aging. I feel
like that conclusion doesn't follow and is misleading, but I'm not sure. Am I
off base?

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?

~~~
Jtsummers
I don't think this is a reasonable conclusion:

    
    
      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.
    

You're suggesting that the probability of dying _after_ 85 decreases. That's
not the case, it continues to rise. If it decreased that would suggest an
_improvement_ in health (un-aging) at 85, which doesn't occur.

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.

~~~
dahart
You misunderstood me and confused the probability of dying by 85 with the
probability of dying at 85. You're talking about the cumulative distribution
and I was talking about the probability distribution.

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%.

~~~
Jtsummers
The chance of death at a given age oughtn't be a bell curve. The chance of me
(33) dying at 60 are much higher than the chance of my coworker (65) dying at
60. There's a shear drop off at the age in question. After that point you have
0 chance of dying at the particular age, it's not a bell curve.

So I feel like I still don't understand what you're getting at in your
example.

~~~
dahart
Do you want to understand? I'll try to help, but it seems like I'm using math
terminology and concepts you're not familiar with, and I don't want to presume
you're interested in learning math.

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](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](https://www.longevitas.co.uk/site/images/ELT15.png)
[http://www.aihw.gov.au/uploadedImages/Subjects/Deaths/age-
de...](http://www.aihw.gov.au/uploadedImages/Subjects/Deaths/age-death-
figure1.png?n=2358)
[http://www.publications.parliament.uk/pa/ld200304/ldselect/l...](http://www.publications.parliament.uk/pa/ld200304/ldselect/ldeucom/165/4051902.gif)

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?

------
sickbeard
Half way through the article the author starts to confuse 'aging' and 'dying'.
I would argue both are inevitable, we all age and we all die but not at a
constant rate. Isn't that what inevitable means?

~~~
nograpes
The author defined aging in terms of the probability of death. I found this
definition helpful rather than confusing. You noted that we age and die at a
constant rate; how would you define aging if not in terms of the probability
of death?

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.

~~~
germinalphrase
I would imagine that the folk definition of aging is more closely align to
your body improving itself vs declining/plateauing.

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.

~~~
nograpes
I think the folk definition of aging is actually aligns quite closely with the
probability of death definition.

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".

~~~
germinalphrase
If you limit your examples to health declines/old age, then - yes. My point is
that the term "aging" doesn't always relate to the old and infirm.

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.

------
lqdc13
The author is somewhat confusing aging and dying. Aging is a mechanism. It is
there for (probably) many reasons. One of them is to protect against cancer,
and therefore from dying. You either age or you get cancer.

~~~
astazangasta
This sort of adaptivism has got to go. First of all, nothing is there for any
reason; it just is. Evolution is an ad hoc process where things happen because
they need to, and they happen based on expediency. There are many facets of
life that escape adaptive constraint - selection has a limited reach.

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.

~~~
lqdc13
This is not a presumption I made. This is believed by many scientists.
Telomeres are just part of the story. There are many other reasons[1,2,3]. The
third link is not a paper so very readable.

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](http://www.impactaging.com/papers/v2/n7/full/100178.html)
[2]
[http://www.nature.com/nrc/journal/v3/n1/full/nrc984.html](http://www.nature.com/nrc/journal/v3/n1/full/nrc984.html)
[3] [http://newscenter.lbl.gov/2008/12/02/cellular-
senescence/](http://newscenter.lbl.gov/2008/12/02/cellular-senescence/)

~~~
astazangasta
I'm a cancer biologist, so I appreciate the relation to oncogenesis. But you
said "It is there for (probably) many reasons". This is what I am contending;
aging is simply there, because that is what happened. 'Reason' is a judgment
we apply, and it's important to appreciate that much of what exists is not
driven by anything we might call "reason". I do not believe that the
collection of phenomenon we call "aging" is uniformly the product of adaptive
consequence. Notably, we die in part because evolution simply doesn't care, or
isn't able, to keep us alive indefinitely.

------
Stasis5001
>"From the perspective of natural selection, once you’re no longer able to
reproduce, you might as well be dead."

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.

------
reasonattlm
I'll note that the authors here favor programmed aging, a vocal minority in
the research community at the moment. This has a number of varieties, but
essentially boils down to the root cause of aging is considered to be
epigenetic changes. So epigenetic changes -> damage.

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.

~~~
findthewords
Any possible news on how to isolate glucosepane so we could even get started?
Last time I checked, there were no solution that wouldn't also dissolve the
surrounding cells.

~~~
reasonattlm
Nothing more recent than this summary post from January - but read the
comments, since a researcher with an alternate approach participated.

[https://www.fightaging.org/archives/2016/01/the-present-
stat...](https://www.fightaging.org/archives/2016/01/the-present-state-of-
progress-towards-clearing-glucosepane-cross-links-a-contributing-cause-of-
degenerative-aging/)

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.

------
ilaksh
I prefer the SENS approach where the assumption is that different types of
damage accumulate, but that there are ways to improve the cells machinery to
repair or improve the problems.

------
majewsky
> The way this graph [of surviving population size over age] has been
> constructed, a straight line going diagonally downward is neutral, or no
> aging at all.

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.

~~~
bsmith89
> The way this graph has been constructed...

It's a log y-axis. A diagonal line downwards is exponential relaxation to 0.

~~~
majewsky
If it is, then the text does not mention it. And I'd doubt it, given that
various lines flat out at the same height which therefore looks like zero.

~~~
nograpes
The article does not mention it, but the cited journal article says that:

"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.

------
tim333
It kind of fits with Kurzweil's guess that in 15 years or so we'll be
extending life expectancy faster than we age. Though he's big into the
nanobots idea which I'm skeptical of. But with advances in AI and DNA
sequencing I can see people figuring out which bits of DNA do what and being
able to modify the aging process.

------
dmh2000
nice contrast to this article at the same site.
[http://nautil.us/issue/36/aging/physics-makes-aging-
inevitab...](http://nautil.us/issue/36/aging/physics-makes-aging-inevitable-
not-biology)

I'll go with physics in this case

------
amelius
One inevitable problem with aging is still that your memory will, at a certain
point, become full.

~~~
crispyambulance
Computer analogies aside, I think that the longevity community (perhaps
justifiably) is ignoring some really critical aspects of aging and dying.

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?

~~~
kiba
People suffer because of aging-related diseases. That is bad. Ergo, we should
cure age-related diseases.

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?

~~~
crispyambulance

        > Then we'll have to choose: do we want newborn babies or really old people?
    

That's the interesting question isn't it? And _who_ gets the privilege to
answer?

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.

------
messel
Fantastic read, very curious about post fertility life and population
stabilization.

------
Pica_soO
If life is a dice, even the biological immortal throw it every time they climb
into a car. In the long run, every methusalem is bed ridden, when statistics
catch up to him/her.

------
ak39
Pic of dead mayflies doesn't look right. They look more like African flying
termites.

------
make3
even in the most optimistic of views, we're all dying some time before the
heat death, that's for sure, unless we alter the laws of physics or move to an
other universe

------
ratsimihah
Let us die young or let us live forever!

------
emodendroket
I feel like this is based more on wishful thinking than a sober examination of
the facts.

------
nxzero
People that try to live forever normally don't live at all.

~~~
nathan_f77
Would you care to expand on this? I don't understand.

------
kaonashi
Death is…

------
huuu
A lot of cultures are telling stories of people over 200 years old.

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/Longevity_claims)

~~~
Retric
I think the much more reasonable explanation is people always tell tall tales.

[https://en.wikipedia.org/wiki/Paul_Bunyan](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

