Re: Macroscopic Emergence in MWI worlds

--- In [email protected], "hibbsa" <hibbsa@...> wrote:
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> --- In [email protected], "Alan" <alan_forrester2@> wrote:
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> > --- In [email protected], hibbsa <hibbsa@> wrote:
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> > > Thought I'd try a summary of where this is going. 
> > >  
> > > First of all, it's important to exclude - for now - MWI conceptions involving conscious decisions, and probably biological decisions. This isn't because what I'm driving at is weak...but that this is the best way forward. So please note we are considering the more primitive, non conscious or pre-conscious/pre-biological world.  
> > >  
> > > By 'emergent properties' I just mean the way macroscopic reality emerges from QM. The specific description I'm using is Deutsch's 'Reality of Abstractions' chapter. In that, he basically describes the way macroscopic properties (say those associated with boiling the kettle) arise with a great amount of independence from the atomic behaviour going on beneath. 
> > >  
> > > Regarding this sort of emergence, it occurs to me that unless there was a huge amount of stability/reliability/repeatability in terms of the emergence of the same macroscopic properties - for any given QM 'object' (I'll describe 'object' below), our macroscopic world would not be stable, nor deterministic, the way we find it. 
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> > There are limits to our ability to predict stuff owing to the divergence of macroscopic universes over time. There's a bit about this in FoR where David discusses chaos theory.
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> > The macroscopic quantities we are used to dealing with are very coarse grained and so they can be the same for objects whose microscopic constitutions are different, e.g. - bubbles in boiling water forming in different places. As the difference between two versions of the same object grow they may become macroscopically different.
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> Hi Alan - thanks for engaging. In his Reality of Abstractions BoI chapter Deutsch speaks of the high degree of mutual independence between the emergent level and the specifics of the underlying atomic arrangement. How would this mutual independence sit with what you say above which seems to go the way of mutual dependence somewhat. 
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> Additionally, the following taken together 
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> - given in many instances the starting point of what becomes a divergence in the multiverse, can be regarded as duplicated on a large scale across the universe, and 
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> - given that each such instance within this universe could manifest any of the quantum histories divergent in the multiverse from a single such event in this universe,and 
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> - given recurrences of such conditions as duplicates within this universe would need to exhibit a very high degree of consistency in terms of the macroscopic emergence produced, in order for our macroscopic reality to be stable and consistent, deterministic and so on, as we find it 
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> --> surely taken together the constraint emerges requiring the multiverse level divergent quantum histories from a single event in this universe to each and all produce the same macroscopic emergence, to the same order of consistency duplicates of the same event would need to produce the same macroscopic emergence in order for this universe to be stable, predictable, deterministic and so on? 
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> > > As an aside, I don't think this issue depends on the question whether macroscopic reality does emerge from the QM world, because to the extent it doesn't, the MWI model cannot represent divergence of, or any impact over, the components that don't (i.e. because the MWI multiverse is purely in terms of quantum divergence). 
> > >  
> > > But the inherent MWI logic does seem to be that all or some macroscopic emergence does arise from the QM world. For example Deutsch's definition of fungibility includes macroscopic objects. 
> > >  
> > > So, the issue I would like to explore is along the following lines. Given macroscopic reality is complex, it seems reasonable to expect there are many 'levels' of emergence involved, and many instances of emergence. It actually seems reasonable to think that pretty much all instances of quantum divergence will contribute toward some degree of emergence within individual universes. 
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> > > The issue arises when you converge, on the one hand, the requirements our own macroscopic world need to meet in order to be consistent, reliable, repeating and ultimately deterministic. With, on the other hand, the supposition all or most instances of quantum behaviour involves or is associated with some emergence. 
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> > > The consequence of taking the two together seems to be that the multiverse has to deliver the same emergence for the same QM in the same contexts. Because....at the level of individual universes, all the different possible quantum histories for a given context of occurrence, reflect *possible* occurences in each participating universe within the multiverse. 
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> > > Now...I think there are a lot of consequences from this, that need to be worked through and considered. The reason I'm not going into those yet is just that, unless people can understand wtf I'm saying so far, there's no point. 
> > >  
> > > But a sneak preview would be, for example, to do with Deutsch's conception of fungibility. Given he includes the macroscopic world, by implication he includes the levels of emergence up through that world. But...by his own philosophical reasoning, to do with, for example non-foundationalist conceptions, higher levels of emergence actually change the physical definition of what 'fungibility' can physically mean. For a simple example, the macroscopic conception of an object moving with constant velocity through space only has meaning in relativistic terms. 
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> > > Likewise - the principle of equivalence disallows certain distinctions. And so on and so forth. 
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> > > Returning to Deutschs conceptions of these issues, it is possible for an emergent level to be independently downward influential on a lower level of emergence. Therefore a higher level of emergence can theoretically be the primary causality behind what would amount to a breaking of fungibility. 
> > >  
> > > One of the implications of this seems to be the following logic: If macroscopic levels can break fungibility, fungibility must therefore be *physically* pegged to macroscopic levels. Which means that, whatever concept of 'being in the same place' Deutsch applies to fungible universes at the quantum level, has to also apply at the macroscopic levels. 
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> > > Which means that fungible universes are also in the 'same place' at macroscopic levels. 
> > >  
> > > Now.....to see the huge significance of where this is going, you have to go back to the question I am asking. If the vast majority of universes in the multiverse produce the same emergence, then the macroscopic reality of the vast majority of universes in the multiverse REMAINS IN THE SAME PLACE. 
> > >  
> > > The consequence of that being, the multiverse is not divergent....but CONVERGENT up macroscopic levels. 
> > >  
> > > Which implies convergence toward ONE macroscopic universe. 
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> > This is all wrong. The emergent laws of physics do not completely determine the macroscopic state.
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> Sure, but I do address this matter with the argument. To the extent the macroscopic state is not determined by emergence from the quantum level, the multiverse by definition has no influence on that aspect of the macroscopic state, since the multiverse can only differentiate at the quantum level (i.e. so can only cause differentiation at the macroscopic level that is emergent from the quantum level).
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> Therefore there is no dependence here on assumptions about what arises by emergence and what doesn't. What does is subject to the arguments I am making which suggest the multiverse divergence from any given point (i.e. ancester universe) is heavily constrained to all and each history produce the same emergence. On the other hand What doesn't emerge from the quantum level, the multiverse histories have absolutely no influence to alter in the first place thus will all feature the same state with no variance (if that state is stable by whatever does cause it)  
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> > Alan
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Anticipating some possible objections: 

1. "You use concepts that contain errors" [could be about initial states, or duplicates of something in this universe being equivalent to divergent histories  multiverse histories of a single instance of same thing in this universe, or no two quantum histories are the same or whatever] 

None of this would matter because all concepts are there for rough illustrative purposes only. The argument ultimately depends only on the same assumptions about this universe as we find it, that are essential for MWI itself to arise as an interpretation of QM (i.e. principle of local realism, determinism, etc). 

E.g. let's say it's invalid to define things like I do above like this 

>given in many instances the starting point of what becomes a >divergence in the multiverse, can be regarded as duplicated on a >large scale across the universe,..... 

If it's not valid it only makes the argument stronger, because we have to return to the universe as we find it which requires macroscopic stability and consistency on small and large scales. Therefore if the objection is about the way duplicate objects (within one universe) get defined, say because the idea of there being the same type of quantum divergence based on similar starting points or whatever. 

Doesn't matter because the universe as we find requires macroscopic emergence be duplicated. So if the quantum histories are never the same, always have different starting conditions, then the choice is between requiring more broadly defined sets of quantum history with more divergence of key characteristics like starting condition, to all never the less produce the same emergent macroscopic effects. 

Or alternatively if that's impossible for some QM law I don't know about, then the macroscopic world as we find it still takes precedence (because without the same assumptions I am using like determinism and local realism MWI never comes about in the first place). So if it's impossible for emergence to go upward, it has to happen downward in some counter intuitive way, or some combination of the two that is consistent with QM, or no causality between QM and the macroscopic world at all. None of these options or any of the others I can think of weaken the argument my end.  

(p.s. I apologize if there is any impression given above of unrealistic confidenc. That absolutely isn't the reality....I do fully expect to be corrected here. It's just that I have obviously attempted to construct the argument to the highest standard I am currently able.) 
  
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