So this is a question I've been meaning to brainstorm for a project I'm planning on. Its inspired by evolutionary biology and how circumstances defined by nature, has the potential to shape life. Things like the gecko's adhesive feet and a bats sonar are good general examples.

Those aren't what I'm aiming for however. The animal trait I'm inspired by, belongs to the jelly fish Turritopsis dohrnii and makes me think in this way:

There is arguably a distinct evolutionary advantage to mortality. It opens up room for the next generation and it allows for evolution to happen at a much quicker pace than it would with members potentially going on forever. You could say, its not until a species ability to gather experience is sufficiently developed, the benefits of longevity wont outweigh the use of well, mortality.

So what causes a few species to live that much longer than others? Old age does not seem to be limited by biology itself, but rather, by what process of acclimatization that species has gone through, right? So I ask this question: Could humanity then, even just theoretically, self-impose a set of limitations and circumstances, that would mimic the outcome of a natural process/setting, that previously granted biological immortality to the jellyfish?

If so, what kind of process would this be? Encouraging marriage later in life? Looking at old age and longevity as a preferable trait? To such a degree, that we eventually evolve people that just don't die of old age?

I would absolutely love input on this, for my project of course =)

  • 1
    $\begingroup$ I think you could argue that immorality is an end to biological evolution $\endgroup$
    – Twelfth
    Sep 14, 2016 at 19:18
  • $\begingroup$ Evolving the biological shape, isnt as interesting as evolving ideas and concepts. And we spend half of our lives relearning those. $\endgroup$
    – Charlie
    Sep 14, 2016 at 19:21
  • $\begingroup$ What do you define as human? If each time an individual's organ would fail it is replaced with a perfect replica (biological or artificial), is s/he still human? Further, is s/he the same human? Does a human consciousness uploaded to a computer mainframe and lacking a physical form still count as human? $\endgroup$
    – Frostfyre
    Sep 14, 2016 at 19:54
  • $\begingroup$ the idea isnt to swap organs, but to develop non-aging? by self imposing restrictions that would lead to it. The question maybe is; what restrictions would work $\endgroup$
    – Charlie
    Sep 14, 2016 at 20:19
  • 1
    $\begingroup$ So, you want to know if some social or cultural construct can induce a biological shift in terms of longevity and what that construct would be? $\endgroup$
    – Frostfyre
    Sep 14, 2016 at 21:01

5 Answers 5


"Who wants to live forever?" - Queen

Tl/Dr: if you want biological immortality, you have to earn it. You have to be able to cope with unexpected disruptions on all scales up to that of specialization, then you can go about trying for immortality.

Forever is a very long time. Even if we reduce the lofty goals from immortality to merely biological immortality, we still have to challenge the way we think about the world to make sense of it.

Nature has no concepts of the individual and the species. Nature does not evolve species to make them more fit -- nature works on a continuum. Individuals and species are human constructs designed to make sense of the reality we face every day. In many cases these human constructs do a remarkably good job of describing the world around us. We can quickly separate many interesting regions into individuals, then categorize those individuals by species. It works pretty well... most of the time.

There are cases where the line becomes more blurry. Bacteria are an excellent source of examples of this. They can form so-called "bio-films" if they sense that there are enough bio-film ready bacteria present in an area. In bio-films, we see behavior more associated with a single multi-celled organism than we do in a cluster of individual single-celled organisms. For example, we often see "dispersion," a key step in the bio-film where it "chooses" to go colonize other surfaces, similar to a tree seeding. The line between individual and group is quickly blurred in these uncharted dark waters of speciation.

Another interesting challenge for our definition of an individual is Pando. Pando is a clonal colony of a single male quaking aspen. You or I might look at it and see it as a collection of individual trees, but if we were to take genetic samples from the trees, we would find they are identical. Pando's roots intertangle and interact with eachother, like many root systems do. If you introduce a beetle to one side of Pando's massive 106 acre body, the tree you introduce it to will react to the beetle. It will send messages through this root system causing trees on the other side of Pando to start releasing chemicals to deal with that beetle!

Even the concept of a "species" is not sacrosanct when you really start looking at it. We see plenty of examples where it gets murky. One example is cross-species breeding, such as breeding a horse and a donkey to create a mule. In this case we create an "individual" mule, but it isn't considered part of either species (and it happens to be sterile, so it can't be its own species).

Periodical Cicadas are an intriguing bit to classify into species. Periodical Cicadas emerge for breeding on either 13 or 17 year cycles. This is a very effective evolutionary approach: predators can't gorge themselves fast enough on the emerging Cicadas, so the vast majority get to breed. There are 7 species of them in North America, typically grouped into 13-year and 17-year groups. However, it is also popular to break them up differently, into 3 groups based on morphology: the Decim species group, Cassini species group, and Decula species group. As it turns out, there are marked similarities between some of the 13 year and 17 year cicadas. The only reason they are considered to be different species is because they emerge on different cycles (that only line up once every 221 years!).

Also consider the interesting world of Lateral Gene Transfer. This is a method bacteria use to transfer DNA from bacterium to bacterium, as opposed to relying solely on the more traditional vertical gene transfer from parent to child. This is a very common vector for trading information about resistances to antibiotics. Not only does this work within a species, but it actually works across species of bacteria! In fact, it even works between kingdoms: There is human DNA in the bacteria responsible for gonorrhea, believed to be transferred by lateral gene transfer.

So if we can't rely on the traditional lines between individuals and species, what can we rely on? One approach I have used is to study "long lasting" self-replicating patterns. This has a few nice behaviors:

  • The definition of "long lasting" is fuzzy, so we can discuss nature on a continuum rather than pinning it down to discrete steps (such as "a segment of DNA which remains intact for 10,000 years").
  • We can permit some level of inaccuracy in our definition of "self-replicating," which is good because DNA replication isn't perfect.
  • If we look at the long-lasting patterns, we do often see gaps which make it easy to capture the concepts of the individual and the species where those distinctions are clear. In the regions where they are not clear, we aren't obliged to trap ourselves into this way of thinking.

We can use this approach to capture a concept of who you are. We typically start "you" at conception, when your cells become genetically dissimilar enough from your parents and they undergo an electrically-stimulated transformation that, if you weren't "you" at that point, could only be considered a malignant tumor on your mother. After birth, we track a rather long-lived pattern which slowly shifts over time as you grow up, but all humans agree that this "perdurable" entity is "you." At some point "you" die, but parts of what made you up live on. If you had children, they share some of your DNA -- that pattern lives on longer than you. If you have a legacy, that pattern lives on. If you were an organ donor, your organs may last longer than you do.

So now we can talk about patterns that "should" live on. I put "should" in scare quotes, because if we're talking about evolution, we have to be careful with assigning purpose. However, we can see some things which seem darn similar to "purpose." For example, the majority of your DNA, the part shared by all humans, has a very strong interest in preserving your DNA. Over time, mutations creep up in DNA, and some of those may be so detrimental to preserving your DNA that there's huge bodies of genetic code dedicated to making sure you die before that happens. This is one reason why it is considered risky to have children when you are older; you have collected more mistakes in the DNA. Some of these mistakes might destabilize the longer-lasting patterns of humanity.

Some of these "mistakes" are a bit more subtle. Consider the evolution of society. The human genome is tailored to encourage societies to form. Each society itself is a long-lasting pattern. The United States of America is nearly 250 years old, and many nations have existed far longer than that. These patterns also have to ensure they are not disrupted. The key to this is that random stuff happens. There was no way to predict that a Ghengas Kahn or a Napoleon or a Hitler would happen to be born in a tumultuous time. So the society has to be able to cope with this, as it happens. If the society falls apart, the human genetics is at risk, so we have a genetic drive to preserve our societies.

There's two extreme solutions to this problem. One is to identify when things go wrong, and fix it; the other is to prepare so that things cannot go wrong. Each of these extremes has issues. If you fix the issue after it happens, you're trusting that you'll be given a chance to fix it. A candle, once snuffed out, never gets a chance to warm back up its wick. If you rely on fixing things after they happen, you are reliant on there being a "quiescent" period after the event where you have time to figure out what happened and fix it. Needless to say, this never happens in war, but it is a very effective approach for natural disasters like earthquakes.

The other extreme solution is to prepare ahead of time. This involve hardening yourself (at any level: individual, society, species, or otherwise) so that you are less affected by change. We build defensive structures so that we are ready for war. However, this approach is energy inefficient. You spend a lot of time preparing for things that never happen. You also create weaknesses. If an opponent can hover just outside of the range you protected for, you find yourself defenseless and you never practiced any other approaches for ensuring the long-lastingness of your patterns.

The interesting region is the middleground between the two, when it isn't so clear whether you are preparing or responding. When a long-lasting pattern responds to something as it happens rather than before or after it happens, they can be far more efficient than either extreme would be. This is where the majority of bodily functions operate. My personal favorite, the Patellar Reflex, is designed to catch us when we land. It's the reflex that occurs when your doctor taps your knee to watch it jump. When you land, you have a very short window of time to respond. If you prepare, by tensing your muscles, you transfer the shock from the legs (which are built to withstand the shock) to the spinal column (which is not). If you wait for it to happen, and the fix it, you crumble to the ground. However, the instant the body sense a stress on the patellar tendon, in front of the knee, it uses a monosynaptic arc, the fastest neurological connection in the human body, to tense your legs at just the right moment. By responding in the moment, we remain a long-lasting pattern.

So we finally have the crux of our answer: to cultivate biological immortality, one must be prepared to protect your DNA from any surprises the universe may bring your way. You have to have powerful DNA repair technologies to defend against UV radiation, and even more powerful DNA analysis tools which will let you analyze any irreparable breaks to see if the changes are beneficial or detremental. You have to have a biological structure which protects you from the environment. If there's cliffs that are 30 feet tall, you either need a body that can withstand a 30 foot drop or a mind that can ensure that you'll never find yourself jumping off a 30 foot drop unexpectedly. If you use a society to keep you safe, you need to make sure that society is prepared to deal with the robbers and the rapists and the genocidal maniacs. Only then will our genome admit that it is safe for us to become biologically immortal.

You can push for biological immortality without trying for this balanced approach, but it doesn't end well. Nietzsche wrote on the topic in Thus Spoke Zarathustra. In that story, "the last man" was a group who pushed for immortality above all else. I'll leave it to you to read, but needless to say, Nietzsche has some pretty strong words to have with that topic.

So what can we do? Well, we can look for existing long-lasting patterns which encourage us to have this sort of in-the-moment resiliency ourselves. There are plenty of approaches out there, and each has its own little piece of the puzzle. Due to my path through life, I find the ones which capture my eye are the martial arts. They teach you how to respond in the moment whenever you can, and only resort to violence when you have run out of options.

The result? I think it shows. Consider Baugua grandmaster Lu Zijian, who passed away 4 years ago at the ripe old age of 118! He taught up until the bitter end, and I think it's pretty clear that he's responded to the surprises in his life pretty darn well!

"Who waits forever anyway?" - Queen

  • $\begingroup$ With the challenges you present I think it best to focus on how to preserve the memories of the individual and thus "achieve" immortality. although you'd only experience living forever as long as there are mediums for you to transfer into $\endgroup$
    – Sarfaraaz
    Sep 15, 2016 at 7:18
  • $\begingroup$ @Sarfaraaz Also important is the ability to transition those memories into something which is more efficient as assisting us in being long-lasting. We certainly couldn't just keep piling up memories like the Junk Lady from The Labyrinth. We'd have to be smarter. We'd have to get those memories closer and closer to some "ideal" memory base which is most useful for the environments we face. Then it would make sense to make those memories long-lasting. $\endgroup$
    – Cort Ammon
    Sep 15, 2016 at 14:23

Select for late breeding

You'd have to select for parents that are fertile well past the median age for fertility. Your biggest problem will be overcoming the urge to breed as early as possible, as then you won't be able to tell if you are selecting on the correct genetics. This is crazily unlikely to happen spontaneously.

What matters is breeding. Marriage, in and of itself, won't have any effect on longevity, as it's a related, but separate, social construct. On the other hand, strengthening the concept of marriage would give greater traction for controlling breeding (and therefore evolution) from the outside.

Religion is your friend here, as most any kind of religious dogma can be justified. Say, a religious taboo against having children before the median age of infertility? You'll probably have to have a really incurious population to keep people from making scientific observations of their own, and messing with your program.

Also, you'll probably need some sort of upper class that is in the know about the plan to breed longer-lived humans. Generation by generation, the upper class will need to gather data about the median age where infertility sets in, and adjust who is allowed to breed accordingly.

Your birthrate will be atrociously low in the first few generations. Roughly speaking you'll be grading on a curve for breedability every generation, intentionally leaving out perfectly viable breeding candidates every step of the way. For this reason, you'll probably need a really large initial population. This will also mitigate inbreeding problems. Genetic disease may require your upper class will have to mix in "outside" blood from time to time.

So there you go. A technophobic, xenophobic society, controlled by an intelligent, tech-savvy religious upper caste that is directing their evolution. Each generation will have breeding candidates of a certain age specifically chosen to be allowed to reproduce.

It won't give you immortality, but given enough time, you'll certainly get longevity.

  • $\begingroup$ "..incurious.." you could also appeal to reason and suggest immortality is worth fighting for? $\endgroup$
    – Charlie
    Sep 16, 2016 at 21:22
  • $\begingroup$ Thats exactly the question: didn't nature at one point present a specific set of circumstances that "forced" the jelly fish mentioned to "beat death"? Could other species, including our own, be artificially put through something like that, to produce a similar or (even) specific result, but perhaps not in the same exact manner (of self-reincubation). Maybe a better question could be: under what circumstancies will a species evolve to not die? $\endgroup$
    – Charlie
    Sep 16, 2016 at 21:24
  • $\begingroup$ It sounds like the question you really want answered is, "How did jellyfish develop this trait?". Barring that, if you want a way it could happen, this is one; there are other reasonable answers as well. I find it unlikely that anything as complex as a human would ever develop something like what you want. Too many of our breeding drivers are centered around social structures or exaggerated, impossible physical characteristics. $\endgroup$
    – Lord Dust
    Sep 17, 2016 at 0:42
  • $\begingroup$ Also, with regard to appealing to people's interest in attaining immortality, I don't see how such a thing could apply. You're talking about evolution, not immediate attainment. People like their immortality for themselves, not for some distant offspring even three or four generations away. You'd be hard pressed to keep a big enough group focussed on evolving something like that for long enough. You'd be seen as a tyrant. $\endgroup$
    – Lord Dust
    Sep 17, 2016 at 0:46
  • $\begingroup$ That depens on the means tho. Say if there was a show on tv, that talked about how old someones grandparents got, perhaps the top model would love a man because of how healthy his parents seemed. Would that be a tyrannical "shift" of value? Or you could suggest people with poor age-genes only got 1 child, and/or applying artificial insemination to get kids with literally the best old-genes in the nation/world. I dont see why you would have to be tyrannical about it, or, it depends on how it could be possible $\endgroup$
    – Charlie
    Sep 17, 2016 at 5:30

Aging Is Probably a Bug, Not a Feature

There is a core problem humanity would need to deal with to attain immortality, by evolutionary or technological means: to our current knowledge, aging does indeed to appear to be a restriction of biology, as we currently know it. Some humans are able to live well over 100 years, and this makes humans one of the longest living organisms of it's general type on earth! There are only a handful of creatures we have good reason to think outlive us, and most of them are a few varieties of shark, some fish, and a few species of tortoise. Note that almost all of these do not outlive humans by more than a factor of 2. Living up to 200ish years is a far cry from immortality.

But what about the other creatures, such as the maybe immortal jellyfish, some trees and fungus? They are radically different than humans in every significant way, they don't have complex brains for memory or complex human-like processes, and they do not reproduce at all like humans do. Most of their life is due to structural reasons, such as the unique uses of regenerative roots or non-moving wood, or due to a kind of "rebirthing" process like the jellyfish or fungus. Applying any of these to humans would require fundamentally re-imagining what a human is, and would not simply be "living for an amount of time not limited by aging processes".

So, why do we age? We aren't entirely sure, but there are a few hypotheses spoken of in anti-aging research reviews like this one, and especially dominant now are ones related to oxidative stress. In short, it is rather literally oxygen that kills you - or less dramatically, the development of free radicals of oxygen resulting inevitably from cellular metabolic processes. To live we need cellular energy, and our basic biological methods of producing and using energy produce their own kind of "pollution", which damages us - slowly, very slowly, but it builds up over our life span until it degenerates the ability of our cells to reproduce, repair, and function properly.

The engineering problem is that humans are complex, and we have many systems to protect us from many things. We have limiters on the extent to which our body produces new cells, for instance, which also has been shown to be a problematic part of the aging process - but if you remove those cell creation limiters, you will develop super cancer throughout the body and die anyway. Processes in the body actually destroy our own cells (autophagy), and this can have aging effects - but its also a process that saves us from other kinds of aging, by recycling damaged cells and removing dangerous misfolded proteins. There are dozens of systems just like this - perfect balance is health, and minor failures lead to cascading degeneration.

Is There Any Hope for Immortality?

Unless you are OK with fundamentally re-imagining human life in terms of rebirthing like jellyfish or regrowing from roots like trees/fungus, the most obvious solution is medical treatment and biotechnological/genetic advancements. The most extreme example of this would be growing a new human body at an accelerated rate, or actually 3D printing a new one from stem cells, which would be genetically identical to the patient, though perhaps with no brain to avoid moral qualms of "are we just killing people to steal their bodies?" A brain surgeon (probably a robot at this point, or at least assisted by robots) puts the old brain in the new body, and after some therapy - tadda, you awaken in a new, young, healthy body!

The problem is that the brain ages too, and so that's even more tricky. You could freeze the brain, scan it with technology we don't currently have, and then reprint it - perfectly intact neuron copies and all yet with undamaged cells and no bad stuff like brain plaque - and when you thaw it (somehow) you again awaken in a new body with a fresh new brain, ready to start over as a young adult but with an intact brain.

Eventually you'll need to deal with issues of memory, though, and we aren't really sure what might happen after hundreds or thousands of years. There is a logical limit of memory, and at best your brain will need to overwrite things, hopefully selectively/strategically, though if we can regenerate a brain from scratch you can probably control neuroplasticity and the brain will rewire and handle memory all on it's own. Can't imagine what the side effects might be, though!

And yes, people may struggle with the Ship of Theseus and related "George Washington's axe" class of problems, as you've replaced every part of the original thing. But if people simply accept that this is OK and it feels fine when they do it, it's really not that big of a practical problem unless you want it to be.

The bigger problem becomes societal ones, like who gets treatment (do you make murderers immortal?), and do you tinker with anything such as with people with limited functions (physical disability, cognitive limitations, less than very high IQ, etc), population/birthing, storage, multiple copies of one person, etc.

Can This "Naturally" Evolve, Without Technology?

I think this would require radical changes in the environment, so far that its way, way beyond simple rules - like living in a world with no threat from bacteria and viruses, less/no damaging sources from radiation, ideal diet, magically solved issues of population and ecological carrying capacity, and even then there is no reason to think that nature would ever evolve immortal humans without strategic, intelligent, intentioanl intervention.

  • $\begingroup$ I wouldn't agree that it is a bug. At least genetic algorithms tend to yield better results if you not using to much individuals from the previous generation. Maybe only taking one to guarantee that the last population includes the best result computed. $\endgroup$ Sep 15, 2016 at 9:21
  • $\begingroup$ I also wouldn't be so sure if missing death by age (or degeneration and getting killed by something else) would be a problem with limited resources. Because fewer die your population must breed less in order to have enough resources. Less new individuals => less recombination/mutation => slower adaption => drawback against a species that die by aging. $\endgroup$ Sep 15, 2016 at 9:21

Immortality granted, in exchange for your soul

What the immortal jellyfish does, is basically to break down and consume itself, then start from scratch. If a human did this, it would not only revert to childhood, but by rebuilding its brain also lose the memories and identity it has accumulated over the years. This is so catastrophic that evolution can't select for it, even if nudged by genetic engineering.

What you can postulate, is that humans have personal "digital assistants" that mirror most skills and memories of its owner, so that a newly rejuvenated human can resume its role in society. This tips the scale in favour of immortal humans, that bring up their own children over and over again.

You don't state what your project is, but if it's an RPG campaign or computer game, the rejuvenation and "digital assistants" offer a mechanism for people to play an in-story character. The character can be a blank slate even to him/her self, but the player reads up on his/her backstory by consulting the assistant.

  • $\begingroup$ The jellyfish didnt always know how to do this, but some circumstance "taught" it to them. Its basically the backstory to a "post-mortal" society, or possibly post mortal anyway. How it could be achieved, and what it would have done to people. $\endgroup$
    – Charlie
    Sep 15, 2016 at 22:42
  • $\begingroup$ What if the reborn personnis raised in the same clan? Parents and children keep exchanging roles and reteaching the same stuff. $\endgroup$
    – JDługosz
    Sep 16, 2016 at 21:56

A possible way would be to :

To breed as much as possible.

Induce a condition, that would require us to develop immortality, like a virus that makes you grow older faster. In a few centuries, we might develop stronger life force to combat the faster pace of browning old to survive.

Control cancer. You know that there is a reason that human cells die... yeap, the longer a cell lives, the more possibilities are that a problem will occur. The safest option as a cell opposed to a human hence is, to die fast before you develop those problems, while also reproducing at a younger age, all of this, so as your host doesn't develop any problems. However, cancer is : cells can't die from aging, and they reproduce uncontrollably, very fast,creating tumors and so on. BUT, imagine an organism that if you cut of his arm, it will regrow back in a few days, can't die from aging and so on... yeeea it would be the definition of a monster like human. At that point though, we would need terrifying amounts of energy to sustain our selves, and hence the food globally would someday die, and we would have to either develop a form that compromises energy consumption with immortality, or face extinction.

Environmental mutations are the controllable ones, hence I believe more in those, if you read the above... But another way would be : Brute force evolution. Let me explain. The name comes from the way of hacking, called brute force. Which technically means to hack something using all possible combinations, and no form of planning or anything like that. Using radiation, to transform and mutate the cells of hundreds of millions of humans randomly, till we see a positive mutation. You've seen victims of high radiation right ? You've also seen Hulk right ? Well that's the premise, to keep on trying till you succeed.


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