↑ comment by Viliam ·
2016-02-25T13:25:21.051Z · LW(p) · GW(p)
I am confused a lot about this, so maybe what I write here doesn't make sense at all.
I'm trying to take a "timeless view" instead of taking time as something granted that keeps flowing linearly. Why? Essentially, because if you just take time as something that keeps flowing linearly, then in most Everett branches you die, end of story. Taking about "quantum immortality" already means picking selectively the moments in time-space-branches where you exist. So I feel like perhaps we need to pick randomly from all such moments, not merely from the moments in the future.
To simplify the situation, let's assume a simpler universe -- not the one we live in, but the one we once believed we lived in -- a universe without branches, with a single timeline. Suppose this classical universe is deterministic, and that at some moment you die.
The first-person view of your life in the classical universe would be "you are born, you live for a few years, then you die, end of story". The third-person / timeless / god's view would be "here is a timeline of your person-moments; within those moments you live, outside of them you don't". The god could watch your life as a movie in random order, because every sequence would make sense, it would follow the laws of physics and every person-moment would be surrounded by your experience.
From god's point of view, it could make sense to take a random person-moment of your life, and examine what you experience there. Random choice always needs some metric over the set we choose from, but with a single timeline this is simple: just give each time interval the same weight. For example, if you live 80 years, and spend 20 years in education, it would make sense to say "if we pick a random moment of your life, with probability 25% you are in education at that moment".
(Because that's the topic I am interested in: how does a typical random moment look like.)
Okay, now instead of the classical universe let's think about a straw-quantum universe, where the universe only splits when you flip the magical quantum coin, otherwise it remains classical. (Yes, this is complete bullshit. A simple model to explain what I mean.) Let's assume that you live 80 years, and when you are 40, you flip the coin and make an important decision based on the outcome, that will dramatically change your life. You during the first 40 years you only had one history, and during the second 40 years, you had two histories. In first-person view, it was 80 years either way, 1/2 the first half, 1/2 the second half.
Now let's again try the god's view. The god sees your life as a movie containing together 120 years; 40 years of the first half, and 2× 40 years of the second half. If the god is trying to pick a random moment in your life, does it mean she is twice as likely to pick a moment from your second half than from your first half? -- This is only my intuition speaking, but I believe that this would be a wrong metric. In a correct metric, when the god chooses a "random moment of your life", it should have 50% probability to be before you flipped the magical coin, and 50% probability after your flipped the magical coins. As if somehow having two second halves of your life only made each of them half as thick.
Now a variation of the straw-quantum model, where after 40 years you flip a magical coin, and depending on the outcome you either die immediately, or live for another 40 years. In this situation I believe from the god's view, a random moment of your life has 2/3 probability to be during the first 40 years, and 1/3 during the second 40 years.
If you agree with this, then the real quantum universe is the same thing, except that branching happens all the time, and there are zillions of the most crazy branches. (And I am ignoring the problem of defining what exactly means "you", especially in some sufficiently weird branches.) It could be, from god's point of view, that although in some tiny branches you life forever, still a typical random you-moment would be e.g. during your first 70 years (or whatever is the average lifespan in your reference group).
And... this is quite a confusing part here... I suspect that in some sense the god's view may be the correct way to look at oneself, especially when thinking about antropic problems. That the typical random you-moment, as seen by the god, is the typical experience you have. So despite the "quantum immortality" being real, if the typical random you-moment happens in the ordinary boring places, within the 80 years after your birth, with a sufficiently high probability, then you will simply subjectively not experience the "quantum immortality". Because in a typical moment of life, you are not there yet. But you will... kinda... never be there, because the typical moment of your life is what is real. You will always be in a situation where you are potentially immortal, but in reality too young to perceive any benefits from that.
In other words, if someone asks "so, if I attach myself to a perfectly safe quantum-suicide machine that will immediately kill me unless I win the lottery, and then I turn it on, what will be my typical subjective experience?" then the completely disappointing (but potentially correct) answer is: "your typical subjective experience will always be that you didn't do the experiment yet". Instead of enjoying the winnings of the lottery, you (from the god's perspective, which is potentially the correct one) will only experience getting ready to do the experiment, not the outcomes of it. If you are the kind of person who would seriously perform such experiment, from your subjective point of view, the moment of the experiment is always in the future. (It doesn't mean you can never do it. If you want, you can try it tomorrow. It only means that the tomorrow is always tomorrow, never yesterday.)
Or, using the Nietzsche's metaphor of "eternal recurrence", whenever you perfom the quantum-suicide experiment, your life will restart. Thus your life will only include the moments before the experiment, not after.
For the "spontaneous" version of the experiment, you are simply more likely to be young than old, and you will never be thousand years old. Not necessarily because there is any specific line you could not cross, but simply because in a typical moment of your life, you are not thousand years old yet. (From god's point of view, your thousand-years-old-moments are so rare, that they are practically never picked at random, therefore your typical subjective experience is not being thousand years old.)
Of course on a larger scale (god sees all those alternative histories and alternative universes where life itself never happened), your subjective measure is almost zero. But that's okay, because the important things are ratios of your subjective experience. I'm just thinking that comparing "different you-moments thousand years in the future" is somehow a wrong operation, something that doesn't cut the possibility-space naturally; and that the natural operation would be comparing "different you-moments" regardless of the time, because from the timeless view there is nothing special about "the time thousand years from now".
Or maybe this is all completely wrong...
Replies from: entirelyuseless, ShardPhoenix
↑ comment by entirelyuseless ·
2016-02-25T16:13:52.646Z · LW(p) · GW(p)
You may be getting at the truth here, but there is a simpler way to think about it.
Quotation from Epicurus:
“Why should I fear death?
If I am, then death is not.
If death is, then I am not.
Why should I fear that which can only exist when I do not?"
Whether you pick your point of view, or a divine point of view, if you pick any moment in your life, random or not, you are not dead yet. So basically you have a kind of personal plot armor: your life is finite in duration but is an open set of moments, in each of which you are alive, and which does not have an end point. Of course the set has a limit, but the limit is not part of the set. So subjectively, you will always be alive, but you will also always be within that finite period.
Replies from: Viliam, qmotus
↑ comment by Viliam ·
2016-02-26T08:06:23.941Z · LW(p) · GW(p)
Because there are other things associated with death, such as suffering from a painful terminal illness, where the excuse of Epicurus does not apply. With things like this, "quantum immortality" could potentially be the worst nightmare; maybe it means than after thousand years, in the Everett branches where you are still alive, in most of them you are in a condition where you would prefer to be dead.
Replies from: entirelyuseless
↑ comment by entirelyuseless ·
2016-02-26T15:14:53.931Z · LW(p) · GW(p)
I agree, except that you are not actually refuting Epicurus: you are not saying that death should be feared, but that we should fear not dying soon enough, especially if we end up not dying at all.
↑ comment by ShardPhoenix ·
2016-02-26T02:14:30.199Z · LW(p) · GW(p)
Very interesting insight. It does feel like it solves the problem in some way, and yet in a quantum version as specified, it seems there must be a 1000_year_old_Villiam out there going "huh, I guess I was wrong back on Less Wrong that one time..." Can we really say he doesn't count, even if his measure is small?
Replies from: Viliam
↑ comment by Viliam ·
2016-02-26T08:01:41.821Z · LW(p) · GW(p)
Can we really say he doesn't count, even if his measure is small?
He certainly counts for himself, but probably doesn't for Viliam2016.
Replies from: qmotus
↑ comment by qmotus ·
2016-02-26T08:51:28.764Z · LW(p) · GW(p)
Viliam2016 is probably relatively young, healthy and living in a country with a fairly high quality of life, meaning that he can expect to live for several decades more at least. But as humans, our measure diminishes fairly slowly at first, but then starts diminishing much faster. For Viliam age 90, Viliam age 95 may seem like he doesn't have that much measure; and for Viliam age 100, Viliam 101 may look like an unlikely freak of nature. But there's only a few months difference there. So at which point do the unlikely future selves start to matter? (The same applies to younger, terminally ill Viliams as well.)