Submitted by Azmisov t3_11qjmwp in philosophy
dolphin37 t1_jcdej3i wrote
Reply to comment by platoprime in A philosophical dive into “Everything Everywhere All at Once” by Azmisov
You’re just mostly describing the basics of QM. That’s not the issue here. The topic is MWI and when the other worlds start existing. I already understand why they need to. It’s disconcerting that you’re using the language of collapse when talking about MWI as the wave function doesn’t collapse in MWI but I can just assume you’re describing the observation of our branch of the wave function after decoherence.
What you need to explain is why all of the many worlds must exist, all of which will be identical copies until their own event of decoherence happens. Each of these, at a point in time, having the same wave function as there’s no entanglement? It needs to be clear why it cannot be the case that we start from a position of one world, which then upon an event of decoherence, creates two worlds. Both of these worlds exist in the same hilbert space as before, but they are now relatively ‘skinnier’.
So if you can explain why all worlds, which will ever feature every event of decoherence, always exist, in a succinct way, then I’ll put that to Sean as the point of debate and he can hopefully help me get it!
platoprime t1_jcdhl2g wrote
>Each of these, at a point in time, having the same wave function as there’s no entanglement?
They are each a part of the same universal wave function. Of course they are entangled. If you know the outcome in one universe you know the outcome in the other.
>Both of these worlds exist in the same hilbert space as before, but they are now relatively ‘skinnier’.
Yes when they decohere they are "smaller" than when they are together. Nothing new is created two things that were coherent became two things that are decoherent. A division of existing space is not the creation of new space.
>So if you can explain why all worlds, which will ever feature every event of decoherence, always exist, in a succinct way, then I’ll put that to Sean as the point of debate and he can hopefully help me get it!
You're saying yourself that one "thick" thing becomes two "thinner" things. That isn't the creation of anything.
>It’s disconcerting that you’re using the language of collapse when talking about MWI
The entire point of MWI is to explain collapse.
dolphin37 t1_jcdrbnz wrote
MWIs ‘explanation’ for collapse is that it doesn’t collapse. You’re just using the wrong language when referring to a collapse that’s all.
I’m still just not seeing anything that explains why all must exist at all times vs them beginning to exist only at a point in time. It’s just not intuitive to start from a position of a potentially infinite number of identical copies. I get why it’s neater from a conservation perspective because everything has its own energy already before docehering but I need to hear something that explains why that can’t be split at the moment of decoherence instead, with the pre-decohered state containing all of the energy within one world.
I think I’ll leave it here as if there were a clearer explanation for this it probably would have come out by now. But I at least understand the position so can ask the question.
platoprime t1_jcdzczr wrote
>(“spin is up” + “spin is down” ; apparatus says “ready”) (1)
>[...]
>(spin is up ; apparatus says “up”) + (spin is down ; apparatus says “down”). (2)
>[...]
>We wouldn’t think of our pre-measurement state (1) as describing two different worlds; it’s just one world, in which the particle is in a superposition. But (2) has two worlds in it. The difference is that we can imagine undoing the superposition in (1) by carefully manipulating the particle, but in (2) the difference between the two branches has diffused into the environment and is lost there forever.
When you have a superposition of two states each state is it's own world.
>You’re just using the wrong language when referring to a collapse that’s all.
The only time I used the word collapse in the comment you're replying to is to say MWI's purpose is to explain apparent collapse. Saying it doesn't happen is still an explanation. You're getting tangled in the weeds with this one.
dolphin37 t1_jceuu3l wrote
Yes in that example you already have entanglement/decoherence in (2), at which point I’ve already said the multiple worlds must now exist. Sean’s language in that very article uses terms like ‘we expect the apparatus to become quickly entangled’ and ‘once our quantum superposition involves macroscopic systems’ and ‘proceed to evolve’ and ‘it is as if they have become distinct worlds’. They ‘come in to being’. They ‘occur’. All of the terminology implies the actions are happening over time.
Saying the possibility for all of the worlds is always there is not the same as saying all the worlds are always there. If that’s what is meant, the language should be clearer. Which I will find out.
And yes you were trying to explain ‘apparent collapse’ but you didn’t use that terminology, like the terminology Sean does in the article linked, you just described collapse multiple times, which isn’t happening. I was just pointing out that it’s not ideal and already stated what I assumed you meant, which is exactly what you apparently meant, but you are again doing the thing where you default to telling me I’m wrong when you actually completely agree with me but have an inability to accept your own fault. Kinda tiring tbh.
Edit: It just occurred to me that you said my objection is that there are too many universes. I didn’t realise you still don’t understand my point this far in 😩
platoprime t1_jchbtln wrote
> It’s just not intuitive to start from a position of a potentially infinite number of identical copies.
You did say this after all.
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