Thought Experiments on Continuity of Consciousness

NickyP
Thu, 23 Apr 2026 07:22:44 GMT

I wrote about continuity of consciousness in my cryonics post: Two Theories for Cryopreservation.

I already stated I’m kind of unsure about it. But now I spend a little more time thinking about it.

Could I make a ladder of thought experiments to get me to believing it’s fake?

Is it really something I can value coherently?

I feel like I mostly have come to the conclusion of not really caring, but I can’t quite articulate why.

Some though experiments on morality.

Suppose you are playing a prisoner’s dillema like game, in a classic decision theory-like setting. You are playing against an exact clone of youself. They have the same memories and information as you, up until this point. They have the same thought patterns as you. You cannot communicate in the mean time.

You can either defect, or you can cooperate. Which do you do?

For me the answer is clear and obvious: cooperate. If you are exact copies of each other, you would make the same decisions in the same situations. You don’t want the other play to defect against you, and you know they will do the same actions as you, so in order for them to cooperate, you need to also cooperate.

With that in mind, we can move to some though experiments.

scattered thought experiments

you make an exact copy of you with all your memories, then 5 minutes later, the original you who got copied dies. Is this fine?

My first reaction to this is that it’s obviously not fine? I value living as myself, and I don’t get to do that if I die, and sure there is a copy of me living somewhere, but that is not the same? is it?

In what cases do I care if someone is a copy of me or not? What do I really care about? I write some though experiments and give my reactions to them

all the parts of my body stay unchanged, I just get older and gain new memories and stuff.

do I care about this person in the future? yes, I care about them a lot. I probably do also care to experience the intermediate parts of the process live them, rather than to just jump to the end state.

I go to sleep, I lose consciousness for a the night, I wake up

Am I still the same person? Mostly I think yes.

I go through life, and year by year, day by day, over the course of your life, many of the molecules that make up your neurons change. are you the same person throughout the process?

yeah this seems fine.

Suppose the universe is something like a simulation. The universe is run on some hardware and gets saved, turned off for a while, then turned back on running from the same state.

I basically think the universe being in a simulation is fine, it’s not really less real in any meaningful sense.

I think the continuity of consciousness here would be fine also, I would be in the same body experiencing the same rest of the universe.

What if the universe was copied? and the original copy of the universe was destroyed, but the copy then could run?

I guess this also seems fine? Base reality would feel identical to me, and I wouldn’t know otherwise.

Thought experiment on copies

you go to sleep, you wake up and you are told that you are a copy of the original you. You can either press a button to save yourself, or to save the identical original version of you that is still sleeping

I toss and turn thinking about this. I think, overall, I would probably just press the [save me] button, since it’s basically the same either way? But it’s unclear.

To some extent, if I was asleep, would I want the copy of me to save the original version of me instead? I guess I feel like if it was truly an identical copy of me, it shouldn’t matter?

But I do have concerns that it might not be the exact same as me. Though in their position then, I would probably still press the [save me] botton too.

But I find this one hard to think about

you go to sleep, you wake up and you are told that you are a copy of the original you. However, you are told the copying went wrong, and the current copy of you has some defect which means you will only live for 30 days, meanwhile the original is healthy as before. You can either press a button to save yourself, or to save the identical original version of you that is still sleeping

I think in this case, it seems obvious to save the sleeping version of me? I probably don’t want the memories of pressing the button anyway, and given we are the same person, and I was asleep, I would want the clone to save me.

What about if there was some symmetry? what if I had 30 days to live, and I could save myself by making a copy then? Hmm, maybe I should just press the [save the clone] option, since we are identical?

Though Experiments on Memories

suppose you lost some small amount of memory, like a random insignificant day from a few months was forgotten.

I wouldn’t be happy about this, but I also wouldn’t be that sad if this was a one-off event and pretty localized, I would basically be the same person.

what about if you forgot the past 24 hours?

Yeah I would dis-prefer this a lot more, but I guess it’s still not that bad, I would be mostly be de-facto the same I guess, but maybe a bit more disorienting, and I feel like my current consciousness would feel more different, even though the longer-term effects might not be that different to the previous case.

So I guess I would care but it wouldn’t be that bad

what if you forgot the past whole year?

ok yeah that would be pretty bad now, I would be pretty upset.

You go to sleep and when you wake up, 5 years have passed. You are told you have lost you memories for the past 5 years.

Uh, idk it would be pretty weird and sad. I would have all my friends and family that I care about 5 years of experiences missed. But if they had time-jumped too, I guess it would maybe be fine? I’m not that sure. It would mostly be like we all life 5 years in the future, which is cool? Though it would be sad to have missed out on those 5 years of development.

Given I experienced what felt like a 5-year time jump, would I want to be able to re-learn the memories of what I had done in those 5 years, or to continue living as I am now?

I guess it depends. I would feel like would just be ending my own existence, and starting the existence of another person 5 years from now.

If that version of me watched a lot of good movies in those 5 years, I would lose out on being able to experience them, I would probably prefer to experience them myself. There might also be bad memories too that I feel like it’s not clear that I took part in exactly.

I think I would probably feel some sense of duty to the version of me that experienced those 5 years to remember those 5 years and live however they were living, but it would feel like I would be transformed into a different person if I suddenly regained all those memories too, so implementation would matter a lot.

The best case would be something like, make a copy of me, and let them to continue experience their life, and I could experience my own life. But if I was now experiencing life as a copy of my current self who was going to be implanted with 5 years of memories? idk, I guess at that point it seems fine, so it feels somewhat symmetric for my copy to start experiencing life and me to get the memories implanted.

This has some slightly weird inconsistencies.

Why does is it OK if there are two copies of me now, but not if there are two copies of me, one now and one back in time? I’m not sure. perhaps that means I would be fine with taking the 5 years of memories now then too?

I can’t decide if wanting a copy of me to experience things rn is completely incoherent or not.

Do I care about this person? yeah. Is it me? mostly kinda. Do I care a different amount for me tomorrow vs me in 10 years vs me yesterday vs me 10 years ago?

I guess I’m not sure how to answer this question.

you are told you can live for 20 years. You have either two options:

you up until 20 years from now, with your current memories until then, then die

you sleep for 20 years, then you live 20 years from when you wake up, except your then filled with memories the copy of you, who has experienced living for 20 years.

Hmm, I guess in some ways this is more complicated. I would prefer to just live in my current self for 20 years, though I really don’t want to live for only 20 years. I would much rather live 40 years.

Bit I don’t want to just have my memories replaced with those of a copy of me who has lived 20 years longer than me.

But also, I know that 20 years from now, I will want to live another 20 years too. Do I deprive that 20-year older version of me from another 20 years of life?

Idk, I think originally I would have chosen the first option, but I guess I have somehow mostly updated to thinking I would choose the second option, since I would now get to live an extra 20 years in some sense.

What do I think about it all now?

I guess after thinking about it more, I feel like I care more about how do I know the copy is truely an exact copy of me more than do I get to experience life continously with the same atoms. But I’m not quite sure what made this click for me, and I probably didn’t get to it that much with the above thought experiments. Maybe i will try explain it more some time.

Discuss