I have a human character who had his mind transferred to a computer via a method where his brain was gradually replaced with digital parts to preserve his consciousness. (Depending on your view of the Ship of Theseus thought experiment, he is still his original self.) This happened in the 22nd century.

If he continuously replaces or upgrades the computer he is stored on, will he be able to live indefinitely, or at least for 17 million years to be able to take place in my story?

Things to consider:

  • The computer does not need to be fully powered off to replace parts
  • He keeps his brain in a place safe from theft, EMPs, etc.
  • He can still run a business through an Android body, so he can afford the repairs/upgrades

Edit: I am looking for if his mind can last that long psychologically. Will his mind degrade over time even if it is no longer biological? Will he still have a will to live after so long?

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    $\begingroup$ This question depends on the exact way this technology works in your story, but I see no reason for the character not to. However, given that more information on the technology is required for a comprehensive answer, I'm flagging this as Unclear What You're Asking $\endgroup$ – Gryphon Jul 20 '18 at 23:58
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    $\begingroup$ The human brain is crazy complex, but it's estimated that its capacity is similar to 2.5 petabytes of digital memory. Let's assume this, and assume it takes 120 years to fill it up. To continuously learn your bicentennial robot would need 354 exabytes of memory. Including support circuitry and ignoring future tech, you'd need a small building to store him. If he can't continue learning. What's the point? Boredom stinks, it's why we're all here. $\endgroup$ – JBH Jul 21 '18 at 6:14
  • $\begingroup$ I certainly hope so. $\endgroup$ – M. A. Golding Jul 23 '18 at 1:56
  • $\begingroup$ @JBH: I was going to bring this up as well. Without updating to memory storage of a human, you have 300 years from start to end on continuous run to fill it up. And that's not accounting to the fact that we don't have a number to what amount of data a human memory takes up on a computer... it could be inefficient... it could be super-efficient. $\endgroup$ – hszmv Jul 23 '18 at 19:48
  • $\begingroup$ Since the technology is hypothetical, then there is no way of telling what would really happen to his mind over time. I'd say it would work whatever way you want it to work. But I'd imagine that since the technology is upgradable (unlike a human brain), that yes he could work out how to have it maintain his sanity over 17 million years. $\endgroup$ – colmde Oct 15 '18 at 9:24

13 Answers 13


If the simulation is faithful, I think that person's experiences will be basically the same as an immortal or very long-lived person living in the real world. So, the question becomes, could a person last that long psychologically, in general?

I think certainly, living for that long is not for the faint of heart! There are many people who won't be able to live that long without tiring of life. But humans are a diverse lot, so certainly, I do think there are some people who would have no problems living that long. I can't speak for real life, since as of now, no one's ever been able to live that long, but there are plenty of examples of characters in fiction who I think have the right mental mindset to live for that long without suffering depression and other adverse side effects. See this TV Tropes page for some examples of such characters: https://tvtropes.org/pmwiki/pmwiki.php/Main/LivingForeverIsAwesome

I personally know of several characters in fiction who have lived much longer then 17 million years, and still seem fairly stable, mental health wise.

One such character is the Face of Boe, from Doctor Who. He is thought to be billions of years old.

Another character is Ashildr, also from Doctor Who. It should be noted that she was initially a normal human Viking girl from the 9th century, and only became immortal because of the Doctor's intervention. She continues living until the end of the end of time, and becomes the last living being in the universe. It should also be noted that like any us with our fallible memories, her memories of older experiences faded with time. She in fact at one point forgot her own name.

I suspect that memory loss plays a vital role in maintaining one's sanity as a long-lived being. If you only mostly remember the last several hundred years or so, that I think is much more manageable than having to deal with memories of billions and trillions of years of experiences.

Another set of characters I would like to mention are Kaguya, Eirin, and Mokou of Touhou Project, all of whom have drunk the Hourai Elixir, and are all completely immortal. Although Mokou was formerly a normal human Japanese girl from around the 8th century, and as of current canon is only around 1300 years old, Kaguya and Eirin are Lunarians, and are commonly thought to be millions of years old. There's an amazing Touhou fanwork called "The Immortal Who Saw the Death of the Universe" by Alison Airlines that's set in the far future which I feel explores the mental states of these immortals in a particularly insightful way. At the end of the first chapter, this fanwork includes a headcanon that explains why Houraijin (ones who have taken the Hourai Elixir) don't get depressed:

Akyuu: "Houraijin's mood may temporarily swing, but they never get chronically depressed. Which is natural, as illness is foreign to them."

Byakuren: "Brain waves of a Houraijin are very calm, as if the subject had a Zen monk's mind. Perhaps this is why they lead such a quiet life in the Bamboo Forest."

Some food for thought.


After the first 120 years, there are likely to be no biological parts left. Our cells can only divide so many times before they stop and die. Depression is largely a biological function, so I would not expect suicide to be an issue after the first 120 years.

Much of what makes us individuals is tied to our biological systems. If, for example, the section of my brain that is scarred from an injury were to be repaired with a perfect electronic replacement, the immediate change would be reinstatement of the ability to experience emotions normally, with the known side effects of improved social ability, better ability to prioritize and focus, and improved memory function. As long as I can get replacement part, I would expect no degradation of this facility over time.

Electronics are not affected by chemicals, so my replacement part would not be subject to fatigue, drugs, hormones, hypoxia, or any number of "environmental" issues that affect biological systems.

As the biological portions of the brain die and are replaced with electronic alternatives, things would change. Emotions are in large part governed hormonally. In my case, having just restored my ability to experience emotions through replacing a nerve connection with electronics, would I lose the ability to have emotions at all as the ability to create and metabolize hormones was lost with the biological systems?

Without an electronic analog to the endorphine system, the person would cease to have emotions. With the absence of emotions, they lose the ability to recognize or respond to normal social stimuli, have reduced ability to prioritize, focus, and remember information.

Human memory is incredibly compressed. We don't remember entire events, only the novel aspects of the events. We fill in the gaps between he "bookends" with reasonable speculation. After 17M years, unless their memory model is changed with a hardware upgrade, they will probably remember their first time at summer camp, but have compressed all other wilderness experiences into a single homogeneous blur. Now, with that said, once they have a certain amoung of electronic modification, it is possible that their memory model could be altered to incorporate mechanical augmentation such as capturing and restreaming experiences.

A number of people (@L. Dutch) have commented on the emotional toll of isolation as it applies to neurotypical humans. However, this person will no longer be neurotypical after a certain point - their neurons will all be replaced with electronics, and the endocrine system gone or replaced with electronic analogues. As one who does not experience normal emotions, I do not experience the effects of isolation in the same way as neurotypical people. I am more than satisfied in that regard by visiting a fast food drive through window once a day. I would expect the character would end up with a similar lack of interest in social interaction.

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    $\begingroup$ The part about not feeling emotions intrigues me. I was planning for this character to be a psychopath who simulates emotion for entertainment. $\endgroup$ – Starpilot Jul 21 '18 at 5:47
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    $\begingroup$ The need for entertainment implies real emotion (i.e. endorphine responses). One of the hallmarks of some autistic people is that they normally have elevated endorphines, so they have no need of external stimulation to be happy. When given drugs to suppress endorphines to "normal" levels, they will begin interacting with people and their environment in a manner more akin to neurotypical people. $\endgroup$ – pojo-guy Jul 21 '18 at 6:22
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    $\begingroup$ @Starpilot - In theory the mechanical brain could be programmed to simulate emotions. Or another option: A small error in the conversion process causes it to be only ~99.9999% correct. Over time the defective translations build up, which cause a mental degradation over a processing time of millions of years, which lead to a quite corrupted psychology. This could not be foreseen in the time in which the process was originally developed, and the corruption prevented the user to recognize it. It's not like there was enough comparison data. $\endgroup$ – Battle Oct 15 '18 at 11:46

You have plenty of writers who have used in their stories computers lasting for million of years.

From this point of view, I see no big issues.

On the other hand, a human consciousness lasting 17 million years would have to face some problems. The first that comes to mind is the company of others.

Good friends we had, good friends we've lost along the way. In this bright future you can't forget your past, so dry your tears, I say. credits

We humans are gregarious creatures, and tend to develop affection and bonding with some other humans. Going through the process of losing some of this bond is painful. I can barely imagine what it means to live a century and keep counting all the people you cared of and who are now gone. Doing this for 17 million years is going to be excruciating.

Moreover, in a time span of 17 million years is long that it is arguable that your character would have human company at all. I mean, around 17 million years ago the hominids just started diverging from the orangutan. Though from a scientific perspective it would be interesting to follow live the evolution of species, one has a lot of spare time to fill with likely no company.

Prolonged isolation is really tough on humans, and I am afraid your character would end up with at least some psychological issues if he is to be alone. But since you mention he has a business, I imagine you imply that there are others of his kind, so maybe he can mitigate the loneliness and find a decent way of passing time.

  • $\begingroup$ I hadn't even considered the fact that if we make it that long, our descendants won't be homo sapiens anymore. But you're absolutely right. $\endgroup$ – Ton Day Jul 21 '18 at 8:16
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    $\begingroup$ We humans are gregarious creatures Speak for yourself, I'm actually enjoying this whole social distancing thing now. $\endgroup$ – The Square-Cube Law Jul 29 '20 at 14:42

I've got this terrible pain in all the diodes down my left hand side

It would certainly not be the first character to have lived that long, nor the first with severe mental health problems. Though not as a result of having lived that long in Marvin's case, but he ended up 37 times as old as the universe and still with that pain in all those diodes.

Genuine people personalities are not going to help here, but then again, most emotions are a result of hormones and once you've replaced everything with electronics that's no longer a problem. The real problem is that the desire to continue to exist is also emotional, and once everything has been replaced with a computer, what's actually keeping your character going?

There are other minor issues like the keeping a single civilisation going that long to maintain a line in compatible technology. Maintaining an economic system that can be used in a suitable manner to provide parts.

Ignoring all the random events, assuming redundant backups and all the usual hardening of systems. The level of economic control required to maintain the necessary infrastructure may require your character to become the controlling entity of a civilisation, which in turn risks overthrow and deliberate destruction, is that the story you want to tell?


Seventeen million years is a very long time. Long enough for (say) the miniscule probability of being hit by lightning in any given year to become significant. The odds are approximately 700,000 : 1. On average, over 17 million years, this should happen over 20 times.

In other words, this individual is likely to die from some kind of freak accident. 17 million years is geologically significant, after all. The odds that any particular spot on the Earth's surface will be stable for that length of time are very very small. If an earthquake, or nuclear war, or the city being flooded don't do them in, odds are a fire, a power failure, or the futuristic equivalent to a hard disk head crash will.

To be resilient against this, this person(?) would essentially need to turn into the Ghost in the Machine. Surviving that long means being transferred to a computer network, and living in the internet, with the program that is their mind being split into running across a redundant network so it never falls offline. The problem there is that now they depend on the network to live, and if it falls apart, they die.

Similar problems arise if you want to have him sit dormant somewhere for most of that time, and then be re-activated. Unless someone is actively copying and maintaining the data in an archive somewhere, after millions of years, the data will almost certainly have degraded. Any given material undergoes chemical reactions that slowly degrade, corrode, or otherwise increase their entropy. These reactions generally progress at a rate so slow as to be negligible most of the time. But over millions of years these reactions would likely efface the delicate structures storing the information.

This is one of the reasons why Jurassic Park won't work; DNA spontaneously degrades over time. Long chunks break apart into smaller ones; the time difference between the age of the dinosaurs and us is so much the DNA in the amber will have completely degraded to uselessness.


It's quite possible that your human will suicide.

If he doesn't start forgetting things he will progressively increase its memories during his lifespan.
After living 17 million years, don't you think your mind will be some different? What is your reason to live so much? Luxury, comfort, enjoyment and money? After that age, everything will be secondary. I'm quite sure a person who lives so much time will be very bored, a maybe he will suicide.

For example, I love to play video games, but after play some time a game I start getting bored of it and I change to other game. Even more, I get exhausted of first shooter games and I play almost nothing of them.
If your character also loves video games, what he will do in 17 million years? He will have played all the games made and for making, he will have experience all the game genres and he will note that all of them are the same thing but just with a different name. He will not hold more games.

The same could happen with life. He may not want to live anymore.

So he must be able to forget, otherwise, everything would be old and boring. And even more, we don't know of his mind could handle that amount of knowledge and memories, maybe he will get crazy or its mind could start to fail.

But that is also a problem, after some time he will forget his reason to live. Why is he living for?

I strongly recommend adding some "updates" or "fixes" to its brain's software in order to not lose its wills nor affect it phycology.

I hope this will be useful as an answer, if not, I'll try to edit it or ultimately delete it.


I don't know why the other answers lean on the character going suicidal. There is no data to support that, mostly because no one has lived that much. Anyway getting older can make people more accepting of death, but it doesn't make them more suicidal.

Now that we are past that, what I see here is a post-singularity version of a thought experiment called the ship of Theseus. Food for thought. Whether the character stays the same is up to individual interpretation.

As for integrity: if his mind is digital, it may be resistant to time. He is all 0's and 1's, and as long as storage and memory parts get proper maintenance, he won't degrade from a hardware point of view. As for software, yeah he may end up corrupting his digital self if he is not careful. But with 22nd century tech, he'll most likely have backups. Even more interestingly, he may spawn copies of himself that evolve differently, each instance going in a different way. More food for thought.


That's impossible to say.

Today's neuroscience doesn't have any data about humans who are older than a bit over 100 years. Dementia is a problem for people of that age, but there are biological reasons for it. Having an electronic brain instead of a biological one generates another unknown variable. There is no way to tell how an electronic brain would be affected by dementia. So you can do whatever works best for your story.

Whether he would want to live that long: The statistics are against him.

In the United States alone, there are 2.7 million deaths each year and 45,000 deaths by suicide. So the risk of getting depressed and killing oneself over the course of one human life is 1.66%. A person living 170000 consecutive human lives would thus have a death by suicide risk of 1 - 0.9833 ^ 170000. This number is so close to 100% that the Windows desktop calculator can't display it.

But maybe some people simply lack any suicidal tendencies at all, so they won't kill themselves even in millions of years? Who knows? We don't have any data in that regard.

  • $\begingroup$ While your point about being a suicide risk is good, there are biological factors for depression, so I don't think the exact statistics are going to apply any more than the statistics for dementia do. $\endgroup$ – Arcanist Lupus Jul 21 '18 at 5:20

If the consciousness of the main character is converted in a digital form raises a number of concerns:

The hardware the consciousness runs on is vulnerable to corruptions. Computers use crude electric methods to read bits, but there may be permutations sometimes. Meaning a 1 can erroneously become a 0. There are algorithms to mitigate this risk, but given enough time errors can still pass through. Another way to mitigate the risk is to run multiple simulations of his* consciousness at once and choose the new state by looking which one occurred the most. But given enough time even this can give errors. The result can be that his personality changes during the journey through hardware corruptions. These errors will also apply on quantum hardware or any other engineered hardware subjected to physics.

The main character becomes disconnected from his original body and therefore there are concerns with identity and gender. Given enough time, wouldn't you want to try something differently? It is plausible given this time that the main character changes.

It depends on the environment of the ship. If the main character has to survive 17 million years in solitude then I don't think he will make it. He will try furiously to end his life because it is the only thing left to do. The way I see the main character surviving is by giving him the sensation that there are still many things left to experience. Either by wiping his memory once in a while and have him repeating things. Or by having the environment be a vast complex place like paradise or a magical kingdom where he feels he has importance and fulfillment. He might need to live in a simulation for that.

I think regardless, the character will be a very different person after the 17 million years but I think it is possible he keeps the same soul.

  • The him can also be her, I used him throughout the discussion
  • $\begingroup$ I doubt that corruptions would be a problem. They will probably behave like mutations in biological bodies and mostly do nothing. The part about having an identity crisis seems illogical, as he is still the same person. Also, he can leave the ship. (For all intents and purposes he could even be the ship) $\endgroup$ – Starpilot Jul 23 '18 at 21:03

While it is possible to live that long, however likely the chance they would kill themselves long before them. It mainly depends on if they are active for the full 17 million years.

If they were to be in a hibernation mode, rarely (Perhaps every million years or so?) waking up and looking at the outside world to note any major occurances, then yes it may be very possible for them to stay completely intact mentally.

Remaining away for even a rough 10% of that time would likely change, or even break them mentally. Pushing them closer towards a self-destruction. However we dont know what the effects of incredible age and experience are, and likely also depends on how strong the person is mentally.


Even for just 500 years, I doubt there will be any biological body remains, and after that I can't say that he is can be categorized as human anymore. This means he will likely adapt to new psychological state that surpass mortal human as a cybernetic hybrid. So he can safely programmed his own brain to not doing suicide and try his best to prolonged and update his existence (therefore also avoid boredom). And we can assume from there it would be a walk in the park for him to become godlike entity in a first million of years.


The Curious Case of Bowerick Wowbagger the Infinitely Prolonged

A recurring character in the Hitchiker's Guide to the Galaxy franchise, Bowerick is an alien who became immortal after "an unfortunate incident with an irrational particle accelerator, a liquid lunch and a pair of rubber bands." Nobody ever was able to repeat this; anyone who tries ends up "looking very silly, or dead, or both."

He initially great time, laughing at other peoples' funerals, making a mint from life insurance and long-term investment, and "generally outliving the hell out of everybody." After a few centuries he is one of the richest and most powerful beings extant.

In the end, it was the Sunday Afternoons that got to him. You know what I'm talking about, that horribly boring time of day when there's nothing to do, nothing to see, and everything's just generally blah. Over time more and more of his life grew to be like this, and it began to pall for him. The end result was that "he began to despise the Universe in general, and everybody in it in particular."

In order to alleviate the boredom, he decides to insult the Universe, by insulting everybody in it. Individually, personally, and in alphabetical order. That's how cracked he'd become. He spent his fortune acquiring the best ship he could, the best computer, and the best entertainment system, and then started out. When he finally gets to "Z" he is killed by the Great Prophet Zarquon, who was particularly irked by Wowbagger's insult, thus ending Wowbagger's eternal suffering.

It is worth mentioning that creatures that are born immortal are capable of handling immortality (usually by ceasing to care about it); those who are born mortal are unable to stop caring.


Making the first money

Data integrity over time will be a problem. The bio data storage needs to be copied, functions need to be emulated. Once that is done, your personality will want to expand processing and memory capacity in order to secure it's own integrity and superiority when competing with other humans on Amazon Turk.

Securing existence

Next thing it wants to do is setting up automatic back ups on several continents with their own independent power source. He wants to extend his moneymaking to pay for a trip to space next. Being away from those pesky humans further secures his longevity. He might then beam his mind state into orbit or back down continuously so that he always has an up to date security copy.

Longevity Memory

Once he got sufficiently complex and able to code, he probably wants to rewrite his personal operating system to make it incompatible with existing or new comuterviruses. The danger is of course, that one or all of the steps change his personality beyond recognition. He might want to store a security copy of himself on a durable memory medium, for example in holographic glass.


Useless Copy

Of course he doesn't need those copies anymore as soon as he did his update. Worse, the update could change his personality, which was the entire reason for making a copy in the first place. But does Update want to change back and become Copy? Probably not.

Stolen Memories

One or several of the security copies may be retrieved by someone and brought to life. Shocked by what he became, Copy may become the worst enemy of Update. Both with comparable abilities physically and talent-wise, both know which passwords the other might probably use, they might be formidable enemies for each other. Also philosophically, they might never find out who of them is the real man. Update has a continued stream of memories, but Copy is closer to the original without changed personality.

Work slaves

No matter who wins, Survivor might want to ensure that never again, a security storage gets away. And that might be too late: some human might have found a way to edit the memories and make fine little work slaves from them. The ensuing battle between Survivor and humanity may leave both in a desperate state.


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