MWI for dummies?

[Amorphos]

MWI for dummies?

I am a bit tired of wacky theories about multi-worlds, so can someone please explain in the simplest and most concise terms possible exactly what the basis behind it is?

http://en.wikipedia.org/wiki/Many_worlds_theory
MWI's main conclusion is that the universe (or multiverse in this context) is composed of a quantum superposition of very many, possibly even non-denumerably infinitely[13] many, increasingly divergent, non-communicating parallel universes or quantum worlds.

Firstly I’d think that at most there’s a very large number [non-denumerable] rather than an infinite amount of universe.
I’d question if infinity can have a beginning [in philosophy not math I.e. in real not metaphoric terms].
I don’t believe you can have an event and indeed a universal set of events that occur without there being information and communication about that. …and hence distinct and separate universes.
Observing is an inept use of terms, conscious observation or otherwise looking at something does not change anything.
You cannot change history, it is fixed, you cannot not have done something that you have done. An event occurred how it occurred and then no longer exists.

wiki
The many-worlds interpretation shares many similarities with later, other "post-Everett" interpretations of quantum mechanics which also use decoherence to explain the process of measurement or wavefunction collapse.

Fundamentally:
Why does decoherence lead to two or more universes? Why does it not simply mean that there are many possible outcomes within the single universe?

Why does measurement change anything? I can understand that making an interaction can change something, but can that rightly be thought of as ‘measuring’ or ‘observing’?

Do we ultimately have something very simple which has been wrapped up in fancy language, that we are all confused by it all because we are using the wrong terms which throw us of the trail - so to speak?
Really what we have here is an inability to qualify reality in usualy scientific terms, its simply more fuid than any explanation or interpretation can possibly represent.
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Fj from ilp forums
"if there are many possible outcomes, but only a single universe, which one is chosen? How does the universe choose which one happens? Most non-MW interpretations call this "choice" collapse. IE all the different possibilities collapse (I think I have this correctly) into one reality. However, the reason why the idea of collapse is unattractive to many quantum physicists is that they don't understand the mechanism for collapse -- they don't understand how the universes chooses which one among the possibilities is to become the real one".
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I imagine its like a puppy stood in front of two doors, it wants to get in as it knows its owner is in there and its hungry, but until the owner shouts it doesn’t know which door to enter.
In other words you have a set of possible outcomes, then real-world events [in the same universe] determine in a probabilistic manner which of the decisions are required for the desired outcome. Naturally as events are relative and in that sense ‘flowing’, there has to be a quantum superposition to connect such fluid events! the whole thing is entire ~ all pathways are taken then whatever pathways are open are then used.
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Fj from ilp forums
"Presumably there are billions upon billions of quantum events going on each second [and hence universes], and each one of them has at least 2, and at most...well, at most is pretty high...possible results, and since in MW each possible result is it's own universe, some astronomical number of parallel universes presumably gets created every second".

I assume that no two events can occur simultaneously then, otherwise two universe with the same changes would occur.

Main point is; how!

How does two or more possible results result in two universes?
When that single event would be creating an entire universe of events. As there must assumedly be a correlation between informations and a physical exchange between the two or more positions in the quantum superposition, then the creation of a new universe from one event would affect the relationships of every other event in the universe ~ thus nullifying or otherwise changing the superposition of each party?


So is MWI a load of sci-fi nonsense?

Does science just want a sexy side to it - so to say, and a means for determinism such that they can be the ones in the right.

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[Sphere]

MW is just an attempt to explain what happens when the wave function is collapsed. Nobody really has a good explanation so the MW interpretation is as good as any.

It is attractive because it allows quantum superposition and wave function collapse without "God playing dice"; nature doesn't arbitrarily choose which quantum state survives the collapse (making all the others disappear forever). Rather, nature simply splits the quantum states up into different realities with nothing having to simply disappear.

There's no real evidence one way or another, so multiple worlds is as good an explanation as any. Or perhaps it is better to say just as bad.

[Amorphos]

It is attractive because it allows quantum superposition and wave function collapse without "God playing dice"; nature doesn't arbitrarily choose which quantum state survives the collapse (making all the others disappear forever). Rather, nature simply splits the quantum states up into different realities with nothing having to simply disappear.

Well god playing dice as well as WMI expects there to be something outside the system - so to say. There is nothing outside universe ~ that’s what defines it, and so the idea that many universes can just happen because there are two or more possible events in a particular instance, means that we then have to invent a space [or god] outside of universe.

I think that the choice is made in the holistic world such that QM works to create the stable reality that we all know. The alt-choice doesn’t disappear imho it just occurs at another location and pathway in the QM soup.

[Imperial Glory]

MW is just an attempt to explain what happens when the wave function is collapsed. Nobody really has a good explanation so the MW interpretation is as good as any.

It is attractive because it allows quantum superposition and wave function collapse without "God playing dice"; nature doesn't arbitrarily choose which quantum state survives the collapse (making all the others disappear forever). Rather, nature simply splits the quantum states up into different realities with nothing having to simply disappear.

There's no real evidence one way or another, so multiple worlds is as good an explanation as any. Or perhaps it is better to say just as bad.

That actualy makes tons of sense