The Ethics of Timelooping

Do you think timelooping has massive ethical implications?

  • Yes

  • No


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Cinera

Deus Lo Vult!
Location
Gallia
I am writing a story (well more thinking about and working on the world building (hopefully) for now) where my MC has the ability to rewind time to designated save points. Let's call him John. So the way this works is John has the ability at a given time t_x to set a save point (provided he has not exhausted all his save slots) and at a future time t_y, John can "rewind" to t_x. The way John experiences this "rewinding" is that at t_x John would have all his memories of the duration [t_x, t_y], so it's a form of mental time travel (this is probably the main form of time travel (at least on a multiverse wide scale) that would be covered in this story). How this time travel actually works has some profound ethical implications.

I do not have a canon model of how time travel works in my story (if I find out that my current model is incoherent, I would throw it out, otherwise I would likely live with the implications of it), so while I do have a favoured mental framework for thinking about time travel, there is not much reason to privilege my particular framework and treat it as anything other than just another model in the model space of how time looping abilities can work.

My world is pretty big with several universes (probably an infinite amount of them), but it is probably strictly smaller than the Tegmarkian multiverse. Different universes have different temporal interactions with our universe, but John's time rewind ideally (I'm no physicist (actually, you can probably assume I have no knowledge of physics beyond what little I retained from cramming for high school exams, but I do intend to keep a coherent model. It is integral to the story that the time rewind occurs everywhere, so if certain details of my world makes that impossible, I would probably shrink it as needed) rewinds time on a multiverse wide scale.

The interesting question for the purposes of this thread, is: what happens at t_{y+1}? After John jumps back in time, what happens to the rest of the world?

There are many different ways of thinking of this. The approach I'm currently using is to imagine timelines. Whenever a rewind occurs, the timeline from origin to t_x (the point of the rewind) is duplicated (or perhaps the duplicate already exists), and the world state at t_x is updated to reflect the new information that John has. Let's call the "source" timeline T_1, and the duplicate timeline T_1.1. If we work with this framework, then what happens to T_1 at t_y has very profound implications. The way I see it there's two basic outcomes:
  1. T_1 continues operation normally.

  2. T_1 is terminated at t_y.

If T_1.1 is terminated at t_y, then by rewinding time John is committing omnicide. He's literally killing an infinite number of people each time he rewinds creating infinite disutility (or the upper bound of disutility if you use a bounded utility function). Suppose John assigns a probability of p to the hypothesis "rewinding time terminates the source timeline". I'm not sure how John assigns his probabilities, but whatever prior he's using — as long as it's sensible — I would imagine that it wouldn't assign a probability below say 10-10 to the above hypothesis (probably several orders of magnitude more in fact). If John is doing an expected value calculation, then the possibility of omnicide should dominate his calculations (even with a bounded utility function) when evaluating whether or not to rewind time. In short, John seems to be getting Pascal mugged (only without an extant mugger).

I mentioned above that either T_1.1 is created from T_1 due to the rewind, or T_1.1 already exists. I think this also has interesting ethical implications of its own. For one, if the rewind causes the creation of a new timeline, then each rewind causes amounts of utility equivalent to the total utility history of the multiverse (and if that number is positive), then the moral thing for John to do is to rewind as many times as possible (if the number is negative John creates even more disutility). Interestingly, if the rewinds creates the new timelines, and the multiverse is net positive utility, then the positive utility created by the multiverse may outweigh the negative utility created by omnicide.

As an aside, even if hypothesis 1 was true, then John may still cause omnicide as there's a multiverse ending event (John believes his time rewinding ability is to avert it (he auto rewinds to a fixed save point at when he first awakened his powers if he dies or gets stuck in an infinite loop)), so if the time rewind clones the timeline, if all possible timelines don't already exist and rewinding creates a new timeline, then it seems to me that John rewinding time is omnicide.


Sidestepping the talk of timelines for a bit, it seems to me that no matter how you dice it timelooping/rewinding has profound ethical implications. After the rewind happens, it's possible to treat the period of time [t_x, t_y] as a mere simulation of the future which the MC now has knowledge about (perhaps John's power merely simulates the multiverse (and informs him of the results of said simulation)). This brings up the interesting question of whether simulated copies of an agent have moral worth. If 1,000,000 copies of Jane Smith exist and I terminate 100,000 of them have I created disutility? If one believes that simulated copies don't have moral worth separate from the original, then I'd like to ask you this question: if someone told you that you were a simulation and decided to terminate you, would you consider it murder? Alternatively, if we found out that this universe was a simulation (and that there was a real "earth" somewhere) should we consider the termination of the said simulation omnicide? In short, do you believe in mindcrime(scraped on github (cause Arbital isn't reliable))?


If one privileges some "real" timeline, I'd like to point out that if the simulation goes on for long enough, the simulated agents may sufficiently diverge from their "real" copies that they're no longer the same moral persons. Alternatively, some entirely new agents may be created in the simulation that would not exist in the "real world".


I find it interesting that literally every other action John takes seems negligible in the face of the astronomical amounts of (dis)utility created by his time rewinding ability. I also wonder how someone who believes(believed?) in "shut up and multiply" would react to that realisation.
 
Some thoughts:

1. If the universe is somehow "destroyed" every time John goes back in time, where exactly is he getting the energy to accomplish this feat? Or, if we're treating universe deletion as some inherent property of universes in response to time travel, then where is this energy coming from and how would it work on a universal scale if the speed of light is such a hard limit? I like to think that any model of physics that included time travel would be able to do so without completly discarding existing physics like conservation of energy.

Even if the act of traveling to the past does somehow create something akin to a Vacuum Decay style chain reaction that creates a sphere of destruction that expands at the speed of light devouring the universe... the effect of such a sphere should effectively be limited to our own Milky Way galaxy. The Milky way is about 52,000 light years across and Andromeda about 2.5 million light years away. So, painlessly wipe out the Milky Way is 52,000 years and start deleting Andromeda 2.5 million years later. That's certainly nasty, but not destroying whole universes. Plus, if vacuum decay spheres were so "easy" to make that time-traveling nerds can make them, then those bombs should be going off all over the place.


2. While we can't really determine if John is deleting universes when he time travels, it should be verifiable that he is creating universes. In fact, these new universes are younger with less entropy and get new information in the form of the knowledge he brings back. If we're assuming the sort of Shut Up and Multiply sort of morality found in Rationalist writings, then destroying a universe to effectively create a new younger one full of new information shouldn't be problematic. After all, looking at our own Earth, we've got existential problems like global climate change, nuclear war, super diseases, other alien races setting off vacuum decay spheres, etc. If John can convince himself that the current version of Earth he's inhabiting is doomed to some vague destruction anyway then deleting that universe and replacing it with a younger one with new information that could improve it survivability is a net positive and therefor totally morally accpetable with no ethical downsides whatsoever!

The ends justify the means and sometimes you just gotta delete a few universes to save the universe. (possible sarcasm)

Of course, that even assumes the universe deletion happens at all. If that doesn't happen then he's basically just creating new universes with no downside whatsoever.


3. If he's using mental time travel, and he's not deleting universes when he travels back, then what happens to the future version of him? This question is something I find a bit more interesting than just saying "Time travel destroys the univese!" like what they said in Back to the Future 2.



I think a more... down to Earth concern might be that John finds out that every time he travels back in time, the timeline keeps going but that incarnation of him suffers a massive case of brain deletion as his consciousness is sent back to his last save point.

So, from his perspective, he might go back to his save point, use his knowledge of future lotto numbers to win the lottery, use that money to pay off Grandma's medical bills and help his friends out, help a researcher cure cancer with future knowledge or help find a missing girl who got kidnapped, etc. However, once he does all those things and made all those people's lives better and decides to go back to his last save point to try another route... suddenly his friends and family find see his spasm for a second and drop stone dead to the floor with cerebral fluid leaking out of his eyes. He was so young and helped so many people! Why wasn't he worried about this?

Then, even if he writes down a letter or something explaining the situation, telling everyone that he's just mentally time traveling and not suddenly dying of a previously unknown disease... how would they react knowing this person they've gotten to know just died? Or, suppose he gets kidnapped by the government or local MIB because he knows too much about their weird secrets, talk about how they have secure prisons for people like him, and he just shugs before spasming for a few seconds and dropping dead with brain fluid leaking out. How would the MIB react to this? Or his friends knowing he was just captured by shady guys never to be seen again? Did he leave any information for others to find? What about those early timelines when he didn't know the MIB even existed and had no way to warn his friends and family?

Or, what if he later finds a way to communicate with all the branching timelines and alternate versions of people he met? Would he feel obligated to meet up with them again and explain what happened or would he prefer to pretend that he really was dead and keep it a secret?

Or, what if he finds a way repeat the process on other people? Letting them become effectively immortal by being able to transfer their minds into the past to their younger bodies... while knowing the side effect of this process still results in their older bodies dying when the transfer takes place? He could have a friend suffering from a disease, repeat the process on him, and give his friend the ability to transfer his mind to the past... only to see them seemingly die from the transfer process shortly after. Mentally, he knows... or hopes that his friend is still alive and now enjoying a younger body in a different timeline, but he doesn't know if he will ever be able to meet up with that version of him ever again.



I guess what I'm saying is that time travel in fiction is best used as a plot device to facilitate the actual story's themes and plot. Back to the Future 1 was a story about Marty getting to see what his parents were like when they were kids. BttF 2 was a romp through a cool future setting with hoverboards and flying cars, a side step into an alternate dystopian Hill Valley, and then going back to the first movie to pull off a heist to get the almanac back without anyone finding out. Then BttF 3 was an old western with some neat high tech stuff Doc Brown made, a bit where Doc Brown falls in love with a woman and Marty has to have a talk with him, and finally a train heist where they can get back to 1985.

Trying to get into the nitty gritty of how exactly time travel works and the ethics of such can make for a good story, but I would strongly advise thinking who the characters are, what their arcs will be, and what sort of flashy stuff the story will have in it first. Then have the exact mechanics of how time travel works fit the story you want to make.

Does this help?
 
I personally like the theory that the force of Earth and its human inhabitants moving forward in time is like a river, and any time travel diverts this river at the point traveled back to. The efforts of one person generally can't divert this massive river very much per day, so in practice the change in utility or other type of value is quite small compared to what the world is already doing on its own. Like how Superman, despite saving lives every day, doesn't have much impact on the global population.
 
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I get the feeling that this was more an opportunity to share your thoughts on a philosophical topic than to actually ask a question about your story, but if you would like a suggestion for how to pull off the rest without killing anyone:

There are an infinite number of universes, and they are not all perfectly synchronized in the time dimension. John thinks that his power works like this:

"Live until t_x. Set save point at t_x. Live to t_y. Revert to save at t_x, with the interval [t_x,t_y] being erased."

In actually, it works like this:

"John!Universe-A lives until t_x, subconsciously chooses a time period (e.g. N days), and activates power. The memories from John!Universe-B are merged with John!Universe-A, along with a false memory of setting a savepoint and choosing to revert time. By definition, both A and B have identical history from t_0 to t_x, and B has an additional N days of history."

After using his power, John remembers living through N days after t_x and then choosing to revert time. He never actually lived through those days, but he has no way of knowing that.
 
1. If the universe is somehow "destroyed" every time John goes back in time, where exactly is he getting the energy to accomplish this feat? Or, if we're treating universe deletion as some inherent property of universes in response to time travel, then where is this energy coming from and how would it work on a universal scale if the speed of light is such a hard limit? I like to think that any model of physics that included time travel would be able to do so without completly discarding existing physics like conservation of energy.

Even if the act of traveling to the past does somehow create something akin to a Vacuum Decay style chain reaction that creates a sphere of destruction that expands at the speed of light devouring the universe... the effect of such a sphere should effectively be limited to our own Milky Way galaxy. The Milky way is about 52,000 light years across and Andromeda about 2.5 million light years away. So, painlessly wipe out the Milky Way is 52,000 years and start deleting Andromeda 2.5 million years later. That's certainly nasty, but not destroying whole universes. Plus, if vacuum decay spheres were so "easy" to make that time-traveling nerds can make them, then those bombs should be going off all over the place.
Hmm, I don't think this objection is very pertinent. The kind of setting where time travel is possible (and happens across an infinite number of universes) wouldn't exactly operate according to our laws of physics. When I said John's time travel destroys the multiverse, I was thinking of a mechanism where the thread simulating that timeline is terminated (as there is no need to keep on simulating said timeline).

2. While we can't really determine if John is deleting universes when he time travels, it should be verifiable that he is creating universes. In fact, these new universes are younger with less entropy and get new information in the form of the knowledge he brings back. If we're assuming the sort of Shut Up and Multiply sort of morality found in Rationalist writings, then destroying a universe to effectively create a new younger one full of new information shouldn't be problematic. After all, looking at our own Earth, we've got existential problems like global climate change, nuclear war, super diseases, other alien races setting off vacuum decay spheres, etc. If John can convince himself that the current version of Earth he's inhabiting is doomed to some vague destruction anyway then deleting that universe and replacing it with a younger one with new information that could improve it survivability is a net positive and therefor totally morally accpetable with no ethical downsides whatsoever!
How would it be verifiable that he's creating a new timeline? Crossing from one timeline to another is impossible except by the mechanism of time travel, and John has no way to interact with the other timelines. I see no way he could feasibly verify whether he was in fact creating new timelines.

So, from his perspective, he might go back to his save point, use his knowledge of future lotto numbers to win the lottery, use that money to pay off Grandma's medical bills and help his friends out, help a researcher cure cancer with future knowledge or help find a missing girl who got kidnapped, etc. However, once he does all those things and made all those people's lives better and decides to go back to his last save point to try another route... suddenly his friends and family find see his spasm for a second and drop stone dead to the floor with cerebral fluid leaking out of his eyes. He was so young and helped so many people! Why wasn't he worried about this?
He doesn't consider it very irrelevant? The other timelines are doomed to destruction anyways? He finds it more likely that they are terminated?

Then, even if he writes down a letter or something explaining the situation, telling everyone that he's just mentally time traveling and not suddenly dying of a previously unknown disease... how would they react knowing this person they've gotten to know just died? Or, suppose he gets kidnapped by the government or local MIB because he knows too much about their weird secrets, talk about how they have secure prisons for people like him, and he just shugs before spasming for a few seconds and dropping dead with brain fluid leaking out. How would the MIB react to this? Or his friends knowing he was just captured by shady guys never to be seen again? Did he leave any information for others to find? What about those early timelines when he didn't know the MIB even existed and had no way to warn his friends and family?

Or, what if he later finds a way to communicate with all the branching timelines and alternate versions of people he met? Would he feel obligated to meet up with them again and explain what happened or would he prefer to pretend that he really was dead and keep it a secret?

Or, what if he finds a way repeat the process on other people? Letting them become effectively immortal by being able to transfer their minds into the past to their younger bodies... while knowing the side effect of this process still results in their older bodies dying when the transfer takes place? He could have a friend suffering from a disease, repeat the process on him, and give his friend the ability to transfer his mind to the past... only to see them seemingly die from the transfer process shortly after. Mentally, he knows... or hopes that his friend is still alive and now enjoying a younger body in a different timeline, but he doesn't know if he will ever be able to meet up with that version of him ever again.
That's an interesting approach, but I probably wouldn't cover it as I expect that the time rewinding mechanism destroys the other timelines.
 
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