[spot5010]

The part that I have trouble wrapping around with many worlds interpretation is how I as an observer end up in one of the many bifurcations. Any links you can share that will help me with understanding that is welcome!

The Stanford Encyclopedia of Philosophy (https://plato.stanford.edu/entries/qm-manyworlds/) goes into this in some depth, and it seems like the right way to think about it is say that "I" in one branch is a different entity than the "I" in a different branch. I have somehow not been able to grok it yet.

And I agree about the naming. I really dislike the name "many worlds interpretation", which seems to imply that we have to postulate the existence of these additional worlds, whereas in fact they are branches of the wavefunction exactly predicted by standard quantum mechanics.

[Nevermark]

> The part that I have trouble wrapping around with many worlds interpretation is how I as an observer end up in one of the many bifurcations.

Pour water down a hill. Water clings to water, and we have hills that already have lots of correlations. We get streams that break up into multiple streams.

How did one stream end up where it is? It seems like a good question, but it is circular. The stream is defined by where it is. You are here (in some circumstance), because the version of you in this circumstance is you.

A transporter accident that creates several versions of you, on several planets with difference colors, doesn't need to explain to each version how they ended up at a planet with their color. Even if for a particular copy, it seems like there should be an answer why they showed up on a planet of a particular specific color. The "why" is just, all paths were taken.

[spot5010]

What you said here makes sense. Forgive me, but I have trouble even articulating what it is that I don’t understand correctly.

Maybe what I meant was this: if I perform a quantum experiment where the spin measurement of an electron could be spin up or spin down, the future me would end up in one of two branches: I measure spin up, or I measure spin down. There wouldn’t be any possible world where I measure a superposition of spin up and spin down, because such a a state is going to decohere rapidly. This makes sense. What I’m unable to grasp is that even though the wave function of the universe contains both branches, “I” somehow experience only one of the two branches.

The answer to that I guess if that the two branches are nearly orthogonal they will merrily evolve independent of each other. But somehow “I” only experience only one of them.

Sorry for the rambling. I’m not able to articulate what I don’t understand.

[Nevermark]

Good questions.

> The future me would end up in one of two branches: I measure spin up, or I measure spin down.

The future "you's" would each see spin up, and spin down, respectively.

We are just as quantum as what we measure. There isn't a scale where entanglement and superposition turn into something else. No classical vs. quantum atoms.

Just as an up-spin qubit touching an up/down qubit results in an up-up qubit pair in superposition with an up-down superposition, conserving the qubit, when we touch a qubit we get "us"-up and "us"-down versions.

No information is created. None is destroyed. We experience a correlation = "collapse" (both versions of us), but the quantum information just continues on as before, qubit conserved.

[qsera]

>But somehow “I” only experience only one of them.

Using the example from the other comment, "You" are the stream and not a drop of water in it.

In other words, you are not an entity with unique identity that traverse the tree of possibilities. You are part of the tree, actually, part of a branch. The branch's existence and your existence implies each other. Like your hand's existence and your existence imply each other. Your hand could not have existed without you (a similar looking one could. but it wouldn't be yours). And you without your hand (you could have had a different hand, but that wouldn't be "you" (which also includes the hand))

[TheOtherHobbes]

The problem with Many Worlds is that it doesn't place a bound on the number of worlds, so you can't derive the Born Rule from it.

That's quite a serious issues. And arguments against that - like Self-Locating Uncertainty, or Zurek's Envariance - look suspiciously circular if you pull them apart.

There's also the issue that if you don't have a mechanism that constrains probability, you can't say anything about the common mechanism of any of the worlds you're in. Your world may be some kind of lottery-winning statistical freak world which happens to have very unusual properties, and generalising from them is absolutely misleading.

There's no way of testing that, so you end up with something unfalsifiable.

[spot5010]

There’s papers that “derive” Born’s rule from the many worlds interpretations, e.g. https://arxiv.org/abs/1405.7907

I don’t claim to understand them though. I have tried.

[Nevermark]

> The problem with Many Worlds is that it doesn't place a bound on the number of worlds, so you can't derive the Born Rule from it.

I have no idea what this means.

Is there a bound on anything in reality, in terms of scale? Beyond its own laws?

I am reminded of how often in history, too much time, or too much scale, were unsuccessful arguments against many theories we accept today. Those critiques died without any need for special arguments, because they don't have a logical basis.

Also, there are not a number of many "worlds". That is a reflection of poor naming. There is an interleaving of all interactions, so if you zoom out, a smeared landscape across all configurations, from the plank scale up.

Because the connections involve both intersection (entanglement) and union (alternate paths), we get bifurcation of classical sized paths (dense entanglements), while the individual particles continue unconcerned by how they appear to create different classical histories at large scale.

And yes it is experimentally validated. This is the theory that everyone accepts in the lab, even as larger scales of experiment continue to progress.

But some people have difficulty believing/visualizing that it continues to work at larger scales. Despite no scale limitation in the theory, no scale related violations ever suggested experimentally, and the strong likely that scale limitations would produce new physics in at-scale observations of our cosmos if they did exist.

[qsera]

> how I as an observer end up in one of the many bifurcations..

Just a pleb here, but that does not stop me from thinking about it..

I think your consciousness is a function of the world you belong. So asking why your are in a certain world, and not in other, is like asking why you are born to your specific parents, and not to others.

So you don't end up in some fork, by a roll of dice, you are already confined to, and defined by a single branch.

So I don't think the exact "you" don't exist in another branch. But another consciousness that only differ from "you" by only a single random event (ie you and this consciousness only differ from you in the observation of a single random event) exist in another branch.

And it is not like this is all orchestrated by some entity. It is just how consciousness and subjective experiences emerges in mathematical structures (+ the set of random events), that does not need rendering anywhere (Mathematical Universe Hypothesis).

Once you understand the hopeless inevitablity of existence, a lot of questions like "When", "how", or "why" of our existence disappears.

You can ask if there is any proof for this, except for some thought experiment. But I think the only thing that can come close to proving this is if we exhaustively searched for other extra terrestrial consciousness and don't find any.

[Sharlin]

Everybody is utterly confused by the hard problem of consciousness. That's just how it is.

[A_D_E_P_T]

"Hard problem" makes it out to be much more difficult than it actually is. To simplify things a little bit, if you combine a spatiotemporal sense (a sense of bounded being in space and time) with a general predictive ability (the ability to freely extrapolate in time and space from one's surroundings,) "consciousness" arises necessarily. It's what having such senses feels like from the inside; the first-person view. It's a matter of degree, of course.

The writing of Chalmers and its consequences have been a catastrophe for philosophy.

[uh_uh]

> It's what having such senses feels like from the inside; the first-person view.

The hard problem is that there is such a feeling at all.

[A_D_E_P_T]

It's not hard at all when you acknowledge that such senses exist in the world, and that you (like others) possess them. As an aside it tends to foster a certain tendency towards empathy.

In essence, you're asking why there's an inside to being a self-modeling system. But "inside" isn't something extraneous, something additional -- rather, it's what "self-modeling" means.

Really the "hard problem" has a very easy answer, but it's a physical/functional answer, and dualists and obscurantists simply don't like it.

[fnordlord]

It's embarrassingly silly to say but I've frequently just boiled down the hard question to the question of "where is the experience of the color blue stored in the universe?" Even as a non-dualist, I still haven't found much of an answer that I like. I'm all ears if you've got a book recommendation.

[A_D_E_P_T]

The question presupposes that "the experience of the color blue" is a discrete object that needs a storage location. But that's the dualist picture in disguise. On a functionalist view, blueness isn't stored; it's what certain neural activity constitutively is when you're that system observing that blue.

As an aside, isn't it more weird that violet and purple look indistinguishable despite being physically so different? It's said that this is because our L-cones (red-sensitive) have a secondary sensitivity peak at short wavelengths. So violet light triggers S-cones + a bit of L-cone. Purple light (red + blue) also triggers S-cones + L-cones. Similar activation pattern = same quale. It's all functional/physical.

Read Tom Cuda "Against Neural Chauvinism." Also Daniel Dennett.

[qsera]

>where is the experience of the color blue stored in the universe?

It is not stored anywhere. It is part of the consciousness that experience it. In other words consciousness comes bundled with everything it will ever feel.

[Sharlin]

So you say that the hard problem of consciousness is explained by the fact that we appear to be conscious?

[A_D_E_P_T]

The kneejerk response would be: Are you not conscious at this present moment? If we were to modulate your spatiotemporal senses with drugs or a lobotomy, do you doubt that you would be very differently conscious, or perhaps entirely unconscious?

I mean, there is a credible first-person answer to that question of yours, which each man can answer for himself.

But considered more seriously, the "hard problem" is an artifact of treating experience as a separate thing that needs to be generated. If you accept that self-modeling systems bounded in space and time exist, you've already accepted that experience exists -- because experience is what such a system is, from the inside. There's no second step where experience gets added. The question "why is there experience?" is exactly akin to "Why is there an interior to four walls and a roof?" The interior isn't a separate thing; it's necessarily constitutive.

[prmph]

How do you know they (and others) possess them?

[uh_uh]

I'd say we are confused about both the lowest (quantum) and highest level (consciousness) phenomena of the known Universe. Quite humbling.

[Nevermark]

We have a theory whose plain reading matches experiment at all scales.

Consciousness is something else. It is tempting for humans to pair mysteries up, pyramids and aliens, or whatever. But there isn't any factual basis for linking the experience of self-awareness with quantum mechanics.

Is there a factual reason we know digital minds couldn't be conscious? Where quantum effects have been isolated from the operations of mental activity. That seems like a premature constraint to assume.

[uh_uh]

I wasn't trying to link the two. Just pointed out that there seems to be a lot of unknowns on the map.