Undergrad A question about Many Worlds and my Remote Control

[Quantum Alchemy]

I get so many different answers to this question so maybe here someone can pin this down.

When I get up in the morning and I turn on my TV, I have over 3,000 channels so is there a universe with a version of me going to each channel? If not, how do I go to one channel over the other? Can my consciousness override the wave function and go to ESPN and cancel out all other possibilities? How would this be possible in the context of M.W.I.?

Say you live in an apartment building with 40 tenants each with 3,000 cable channels. Does there need to be 120,000 universes where each tenant has a universe for each channel? If not, how do observers cancel out the other probable states of the wave function?

Right now I'm thinking about going to Outback for Dinner but I may change my mind. Does there need to be a universe where I visit every restaurant in the city and if not how do I cancel out the probable states of the wave function and choose just one?

I'm trying to figure out if M.W.I. is a plausible interpretation or does it belong with the moon is made out of green cheese. If every observer from a human, dog, cat or ants creates a bunch of universes every decision, how can this really be taken seriously? When ants create an ant hill in the backyard does there need to be a universe with an ant hill at every point in the backyard?

How do observers make decisions in M.W.I.? Do we make decisions? If we don't make decisions why does the wave function split? Will I go to Dinner because I'm hungry or will I go because some split of a thousand other universes occurred? If I cause the split, how does proponents of M.W.I. say this is accomplished? What gives me the power to cause the wave function to split?

 

[jedishrfu]

You're trying to extrapolate a scientific theory into the classical world and this is way beyond what anyone can really answer. We just don't know.

The wiki article describes the many viewpoints that are taken.

https://en.wikipedia.org/wiki/Many-worlds_interpretation

 

[andrewkirk]

The post contains many questions. I'll just address a couple.

I'm trying to figure out if M.W.I. is a plausible interpretation or does it belong with the moon is made out of green cheese. If every observer from a human, dog, cat or ants creates a bunch of universes every decision, how can this really be taken seriously?

Typically when somebody asks is something is 'plausible' they are asking whether it is consistent with our 'common sense' or 'folk' intuitions. If your criterion for accepting a hypothesis is whether it is consistent with those, it would be better to stay away from quantum mechanics, and probably from relativity theory as well. One of the glories of physics is that it does seem so weird, and so inconsistent with our simple folk intuitions. Many versions of the many-worlds interpretation postulate infinitely many worlds, which is no problem from a logical point of view, but troubles many people's intuitions. It doesn't trouble mine but, to each their own.

Will I go to Dinner because I'm hungry

In quantum mechanics, and in much of physics, one is better off completely discarding the notion of 'cause'. It is a philosophical, not a scientific concept, and even philosophers dispute whether it has any meaning. David Hume famously said he could find nothing in the physical world that corresponded to the notion of a 'cause'. Bertrand Russell wrote an essay on what a slippery, and often meaningless, notion 'cause' is.

Your hunger will be one of a number of factors that are present prior to your going to dinner, and such that in worlds where they are not present, you did not go to dinner. Others will be things like your getting out of your chair to walk to the kitchen or restaurant, your having worked to earn the money to buy the ingredients or pay the restaurant, etc etc, all the way back to the Big Bang.

One of the great things about science is that it allows us to do calculations and make predictions about things like whether you will go to dinner, without ever needing to mess with elusive notions like 'cause'.

 

[Quantum Alchemy]

You're trying to extrapolate a scientific theory into the classical world and this is way beyond what anyone can really answer. We just don't know.

The wiki article describes the many viewpoints that are taken.

https://en.wikipedia.org/wiki/Many-worlds_interpretation

I'm not trying to extrapolate a scientific theory into the classical world, proponents of M.W.I. do that without me.

For instance, when a split occurs, how is another universe created? Is it another universe or a world in the same space? Is it a real world or a projection of a world?

These are just basic questions you would think would have an answer.

There's 1,518,207,412 websites online according to a 2019 survey. In order to surf the web, does their have to be 1,518,207,412 versions of me visiting each website? And is this true for the 4.39 billion internet users worldwide?

Do you see how this gets ridiculous? I would think proponents of M.W.I. would have some answers.

 

[andrewkirk]

I would think proponents of M.W.I. would have some answers.

To have an answer, one needs to have been asked a coherent question. The only questions in your latest post are:

1. how is another universe created?
2. Is it another universe or a world in the same space?
3. Is it a real world or a projection of a world?

These questions are not coherent because they are full of undefined terms. What is a 'real world' or a 'projection of a world'? What is 'another universe' or a 'world in the same space'? What does it mean for a universe to 'be created'?

You are asking about things that have no meaning in the context of quantum mechanics. There are no answers because they are not meaningful questions.

You are entitled to find MWI ridiculous if you don't like how many worlds it postulates. That's just an opinion - a feeling - and not something that can really be responded to. There are others that feel that way too, but many don't.

 

[WWGD]

See my answer in the next world. Way better than the one in this one.

 

[PeterDonis]

When I get up in the morning and I turn on my TV, I have over 3,000 channels so is there a universe with a version of me going to each channel?

It depends on whether anything in the process that goes on inside your brain that leads you to choose a channel has any meaningful quantum indeterminacy in it, i.e., whether anything in that process can be considered a quantum measurement with multiple possible outcomes. If that is the case, then according to the MWI, every possible outcome is realized.

Whether or not it is the case that the processes going on in people's brains have any meaningful quantum indeterminacy is an open question. So far nobody has produced any experimental evidence that there is, but also nobody has come up with a way to prove that there is not.

 

[WWGD]

I'm not trying to extrapolate a scientific theory into the classical world, proponents of M.W.I. do that without me.

For instance, when a split occurs, how is another universe created? Is it another universe or a world in the same space? Is it a real world or a projection of a world?

These are just basic questions you would think would have an answer.

There's 1,518,207,412 websites online according to a 2019 survey. In order to surf the web, does their have to be 1,518,207,412 versions of me visiting each website? And is this true for the 4.39 billion internet users worldwide?

Do you see how this gets ridiculous? I would think proponents of M.W.I. would have some answers.

But why stop there? Take a measurement of temperature. There are infinitely- many outcomes and for each there is a world where you can make additonal measurements, etc.

 

[EPR]

People would lose their mind if they directly observed quantum behavior. So far it's known it's incompatible with common sense or sanity. And we can only infer about it but if you could see all possible locations of a moving bacteria, or a cat in 2 states, you'd first ask 1. What happened to the unobserved possibilities? Where did they go? Were they 'real'(unresolved question of physics) 2. Am i still sane? The interpretations seem 'crazy' because the quantum is not classical. And the 2 domains are incompatible.

 

[Lord Jestocost]

How do observers make decisions in M.W.I.? Do we make decisions? If we don't make decisions why does the wave function split?

"The MWI is a deterministic theory for a physical Universe and it explains why a world appears to be indeterministic for human observers" ( https://plato.stanford.edu/entries/qm-manyworlds/).

In case you believe that you are nothing else but a physical object in a deterministic physical universe, there would be nothing that you could decide.
In case you believe that your mind is free to will, you would regard MWI as a ridiculous interpretation of QM.

 

[EPR]

Determinism failed to account how superpositions translate to classicality('particles' becoming food, sensations, awareness, etc.). If i am reading condensed matter physics right, there is more going on than straight down-up causation.

Oh well, there are no 'particles'.

If QM is a true description of reality, we know next to nothing about it.

The MWI is a desparate attempt to explain the unexplainable by evoking multiple universes to avoid lapsing into conspiracy and mind stuff. In that it fares well albeit at the price of additional assumptions. It's more scientific and draws much popular support.

 

[Mentz114]

Determinism failed to account how superpositions translate to classicality('particles' becoming food, sensations, awareness, etc.). If i am reading condensed matter physics right, there is more going on than straight down-up causation.

Oh well, there are no 'particles'.

If QM is a true description of reality, we know next to nothing about it.

The MWI is a desparate attempt to explain the unexplainable by evoking multiple universes to avoid lapsing into conspiracy and mind stuff. In that it fares well albeit at the price of additional assumptions. It's more scientific and draws much popular support.

If the results of EPRB experiments are telling us something significant that is in the 'laws of physics' then the MWI predicts branches where this never happens, which suggest that the 'laws' concept is faulty from the start.
Is that a contradiction ? I think this has been discussed elsewhere but I can't find it.

 

[A. Neumaier]

Say you live in an apartment building with 40 tenants each with 3,000 cable channels. Does there need to be 120,000 universes where each tenant has a universe for each channel?

No, There need to be the much larger number of $3000^{40}$ universes, since this is the possible number of combinations of channels chosen by all users in the building. If you add all other choices people make on earth, you get a ridiculously large number of universes. And the splitting proliferates multiplicatively each morning! Or indeed whenver there are choices about anything in this world... This shows that the splitting is meaningless gibberish.

One of the great things about science is that it allows us to do calculations and make predictions about things like whether you will go to dinner, without ever needing to mess with elusive notions like 'cause'.

and without believing any of the MWI mantras!

These questions are not coherent because they are full of undefined terms.

Just like the many terms the MWI plays with!

whether anything in that process can be considered a quantum measurement with multiple possible outcomes.

Surely making a choice is a measurement of the observable ''Which channel will be displayed in the next moment'', which can be encoded into quantum language.

 

[Demystifier]

When I get up in the morning and I turn on my TV, I have over 3,000 channels so is there a universe with a version of me going to each channel?

It can be decided by an experiment. Choose one channel each morning and record the statistical distribution of chosen channels. If the distribution obeys the Born rule, then the answer to your question is - yes.

 

[A. Neumaier]

It can be decided by an experiment. Choose one channel each morning and record the statistical distribution of chosen channels. If the distribution obeys the Born rule, then the answer to your question is - yes.

No. You forgot to reveal to us which model to use to decide on the state to be used in Born's rule. Without that, no experiment can decide the issue. But even given a model, the suggested experiment can only check whether or not the model is adequate.

 

[Demystifier]

No. You forgot to reveal to us which model to use to decide on the state to be used in Born's rule. Without that, no experiment can decide the issue. But even given a model, the suggested experiment can only check whether or not the model is adequate.

Well, conclusions from almost all experiments in modern physics are model dependent. Think e.g. of the discovery of Higgs or dark energy.

 

[A. Neumaier]

Well, conclusions from almost all experiments in modern physics are model dependent. Think e.g. of the discovery of Higgs or dark energy.

But there the models are spelt out before making the experiment!

 

[jedishrfu]

Before we get off topic, I think you guys @Demystifier and @A. Neumaier should hash this out in your own thread as part of the Many Threads model of the universe.

 

[WWGD]

Edit:Aren't there , according to MWI, worlds where MWI itself does not apply, where there is no branching? Ones with different choices for respective QM laws? Do Mathematical theorems themselves apply in all worlds? If no, I am curious to see the one where Godel's theorem does not hold.