Problems with Many Worlds Interpretation

[Ken G]

But in so many places on the web and in books, CI is defined differently, so that non-unitary collapse happens whenever any classical measuring apparatus makes a measurement.

The way I would put it, a measuring apparatus achieves a certain type of mixed state on purpose, and then our perception is where the collapse comes in. So we have learned to create mixed states in a certain type of way, such that the perception that "collapses" the mixed state will allow us to do science on the outcome. Mixed states (and the decoherence that produces them) happen naturally too, without any measurement, the measurement is just how we've learned to take advantage of this. But none of that is different in CI or MWI, the difference only appears when we account for the perception of the mixed state, and decide how important we are going to regard that perception as.

In am now wondering if your 'CI' and my 'MWI' are the exact same thing...

I would say the difference is in which we view as "the reality"-- the perception of collapse, or the mathematical description of the unitarity of closed-system evolution.

 

[Ken G]

Doesn’t your second statement cast doubt on your first? I think we agree that, at least from an empirical standpoint, unitarity is already abundantly falsified, and yet this doesn't cause anyone to jump ship.

That depends on what we mean by "falsified." To an empiricist, it is indeed falsified, because the reality is what we perceive it to be (when consistent), so if we don't perceive unitarity, it ain't there. But to a rationalist, unitarity is not falsified, because the observations are consistent with unitarity if we simply say that the observer is an open substate of the closed system, so the observer cannot be objective about the state of the whole system. To the latter group, the only way to falsify unitarity is to show that unitary evolution of a closed system doesn't work, when the system is later opened. That would require falsifying quantum mechanics. There shouldn't be any way to falsify either MWI or CI without doing that.

Maybe you have in mind the idea that the part of quantum mechanics presently believed by everyone to be unitary – namely, the Schrodinger evolution - might be found to fail, and need to be modified in such a way that the state evolution was no longer precisely unitary, and you think such a “change of postulates” threatens the motivation for MWI.

Yes exactly-- the theory of quantum mechanics as it stands today is essentially the Schroedinger equation for closed systems, and the Born rule for observations that open them. How we regard that "opening" of the system is the crux of the difference between MWI and CI, but this difference is not in the outcome of the opening, it is in the perceived significance of the opening. But if the closed part wasn't unitary, and there were no other simple postulates to point to (this may be the key addition), no MWI enthusiast would hold to it any more, I feel. Hurkyl can speak for himself, but I'd be amazed if he didn't agree.

I think you were nearer the truth in your previous message, where we agreed the main motivation (at least technically) for MWI in QM is the uncertainty principle and its consequences, not a yearning for unitarity per se.

I think the HUP is the reason we must choose an interpretation like MWI or CI, but the "many worlds" of MWI don't come from the HUP, which is empirical, they come from whatever postulates account for the dynamics. In my "quasi-classical" version where we have a HUP but no Schroedinger, we could still generate a "no collapse" interpretation, and it would still be unitary-- it would just be the postulates of classical mechanics. If we didn't have classical mechanics, it would be like not having Schroedinger-- with no simple and well-unified set of postulates to hold to, there'd be no motivation to retain the unitarity of many worlds. Without a working set of postulates, there just wouldn't be any anchors for the rationalists to hang their hats on. They'd have to tolerate the "collapse" interpretation, they couldn't object if it wasn't violating any other simple set of seemingly valid postulates.

This has led some prominent MWI advocates to adopt the view that the number of self-coherent worlds is actually constant, and they just are partitioned into shifting equivalence classes.

Good point about the time reversibility, although it just means we must modify the analogy to allow the "river" to re-merge. Can we recall two separate pasts? It sounds like the same "perception game" that they play with mixed states-- they would say we do perceive multiple outcomes, and we do remember multiple histories, we just don't realize it somehow. It's as though our brains can only hold one coherent thought at a time, skewing our view of both the present and the past. There's nothing exactly wrong with it, it just seems like an awful lot to hang on the structure of the simplest postulates.

Indeed, some MWI advocates (e.g., Deutsch) contend that MWI implies it actually IS possible for an observer to gain awareness of their multiple, mutually exclusive, histories.

That sounds like a falsifiable claim that MWI proponents had better find a way to avoid! Any theory in which we can recall multiple pasts, or perceive multiple outcomes to a single experiment, represents a radical detour not only for quantum mechanics, but for science itself. One had better have good reason for such a violent departure from the scientific method, it really seems like opening the door to "woo-woo" claims (like past-life regression, etc.). I'm sure Deutsch doesn't want to do that!

One might argue that it’s unfair to expect MWI to resolve the “arrow of time” problem, because it is also an open problem for other interpretations, but I would answer that it is an especially acute problem for MWI, because without a clear and explicit resolution of the arrow problem, we can’t even really say that MWI gives any intelligible account of observations at all. MWI isn’t really an interpretation of quantum mechanics, it is an idea for an interpretation of quantum mechanics.

This is not necessarily a bad thing for MWI-- it does seem quite possible that the arrow of time is indeed a kind of illusion that comes from how we process information rather than what is "really happening." My problem there is, as primarily an empiricist, I feel that a consistent perception cannot be regarded as an illusion-- it is the definition of what is "really happening". Rationalistic approaches to what is really happening seem so futile in view of how much farther science has yet to go.

But I see that both empiricism and rationalism face inherent paradoxes: all empiricists must engage their brains to interpret, rationally, their perceptions, and all rationalists must engage their perceptions of information processing to be able to create a mathematical argument in the first place. This may very well be the reason that we need both rationalistic and empiricist elements to make science work.

Careful with the ant and the log there... you are smuggling in the very dualism that MWI seeks to exclude on principle. According to MWI, there is no log or ant, there is only water. You are nothing but one particular streamline in the flow.

Yes, in effect what I was doing was interpreting MWI from an empiricist standpoint, like "this is what rationalism looks like to the empiricist." It really should be characterized like a rationalist would.

The main motivation for MWI isn't a yearning for unitarity, it is an abhorance of dualism (which of course underlies the kind of empiricism that you've described).

Unification is certainly the rationalist dream, so any form of dualism would be anathema to this goal. Unitarity is just nicely unified, it's always the simplest postulate. What could be simpler than Parmenides' "change is logically impossible"? Ironically, the "many worlds" approach is actually the way to have just one universe, and it never changes, rather than one universe that changes along a time stream. I agree this will always be the goal of rationalism, regardless of whether or not the postulates of QM are falsified-- I just think they wouldn't feel they had a leg to stand on if they couldn't point to some set of currently viable unifying postulates.

 

[Hurkyl]

If you mean by that a one-to-one correspondence with the state space of the measuring device, that is exactly what I am saying an empiricist would never allow.

Empiricism does not assert 'what cannot be observed does not exist'. Instead, what is observed certainly^* exists; about what is not observed we are still free to make suitable assumptions." (I'm paraphrasing von Weizsäcker who was talking about CI, although I don't know the context)

Von Weizsäcker was interested in avoiding paradoxes. I'm interested in understanding the theory, and in avoiding assumptions that unnecessarily limit the scope of applicability of QM.

*: I really don't like absolutes, but I didn't feel it worth rephrasing this bit.

I put no emphasis on the label "eigenvalue," I put emphasis on two things:
1) we perceive definite outcomes of observations
2) the theory of quantum mechanics has a name, and a prescription, for referring to those definite outcomes, and that name is eigenvalue and that prescription involves associating measurements with operators. So #1 is what we perceive, and #2 is how we attempt to understand and unify those perceptions. No interpretations yet.

#1 has already strayed into the realm of interpretation -- it's taking the elements of the mathematical theory of quantum mechanics and interpreting them as saying something about something else -- in this case, about 'reality' and what we 'perceive'.

This approach to interpretation makes the observers god-like. To make observers frog-like, quantum frogs have to be quantum systems and make their observation by quantum interactions -- you need to interpret the the measurement theory as describing the quantum system. (plus some sort of interpretation that says this setup reflects reality)

Yes exactly-- the theory of quantum mechanics as it stands today is essentially the Schroedinger equation for closed systems, and the Born rule for observations that open them.

Which has the problem that observers are gods, and you need multiple sets of rules.

The other main way is Schroedinger equation for closed systems. Subsystems of the system are open, and the mathematical aspect of the Born rule pops out as merely being the operation for extracting the state of the subsystem from the state of the whole.

 

[Hurkyl]

Or if MWI considers that there are multiple worlds that are all sort of similar sharing their part of each outcome (each observed eigenvalue), how on Earth could the worlds be coordinated over time? How could each have a "me" flipping a coin or observing a collapsed value, when after some n number of generations of collapses each world would have vastly differing observers and observation events? This view seems impossible.

I wanted to give a short response from another bent.

How are they coordinated? The Schrödinger equation. Multiple "worlds" and "splitting" aren't fundamental parts of MWI. Instead, they are derived descriptions -- attempts to organize, quantify, and describe the behavior of a quantum state obeying the Schrödinger equation, and somewhat geared to make the connection with other views more plainly evident. (e.g. someone in any particular world sees things as if the universe had collapsed down to that particular component of the quantum state)

 

[Hurkyl]

Gedankenexperiments are ways of probing theories, only real experiments can probe reality. All the same, they are very valuable for understanding theories, and no one would ever "object" to any gedanken on the grounds that a different one is "better." When we look at our theories, we should look at them from all angles, and so we should address all the gedankenexperiments, as well as all the viable interpretations. We just shouldn't imagine we are learning about reality when we do that-- we are learning about our theories.

Agreed! Except for the penultimate phrase.

Real experiments probe reality, but all that gives us is raw data. Learning requires us to analyze the data, and from the analysis, synthesize an understanding.

Physical theories are synthesized from the analysis of that data. Learning and understanding such theories are thus part of the "synthesize an understanding" part of learning about reality.

 

[Ken G]

Empiricism does not assert 'what cannot be observed does not exist'. Instead, what is observed certainly^* exists; about what is not observed we are still free to make suitable assumptions."

But no doubt he is talking about concepts like "electrons" or some such thing that we don't directly observe. He is not talking about things that we should by all rights be able to observe, but don't-- like other outcomes to our observations. That's a very different category of "what is not observed", and one that I would certainly feel empiricism would rule out as part of reality. Indeed, it would have to-- for if we allow other outcomes that fit the theory to occur, how can we rule out other outcomes that do not fit the theory? It is just plain not empiricist to assert that outcomes that fit the theory, but are not perceived, should be regarded as real, simply because they fit the theory. In empiricism, theories are tailored to fit data, data does not just check theories.

This approach to interpretation makes the observers god-like. To make observers frog-like, quantum frogs have to be quantum systems and make their observation by quantum interactions -- you need to interpret the the measurement theory as describing the quantum system.

This is the crux of the matter. To assert that "observers are quantum systems" is a fundamentally rationalist approach, you are saying that observers are ruled by a theory. That's not empiricism, observers are never "ruled" by anything, they are the definers of truth. No theory ever "rules" nature in empiricism, theories are invented by physicists to understand observations. Thus, no observer can be ruled by a theory, all you can do is ask if observers can be treated with the same theory that other things are, but treating anything with a theory is just an analytical choice, not a way to establish what is true.

I wonder why you are so loathe to accept that your approach places what you can think about, and make postulates about, above what you perceive. I would say that is almost the clearest defining characteristic of both MWI, and most everything you say about quantum mechanics. And it is classic rationalism. I really don't think there's any crime in it, but we should see it for what it is.

Which has the problem that observers are gods, and you need multiple sets of rules.

It's not that they are gods in the way we used the "god's eye" view before, but they are certainly gods in that their consistent perceptions are definitely what is real (in empiricism). You object to the multiple sets of rules, but that is your rationalism coming out-- Occam's Razor has no objection to multiple sets of rules if they are needed, and the empiricist says they are needed in quantum mechanics.

The other main way is Schroedinger equation for closed systems. Subsystems of the system are open, and the mathematical aspect of the Born rule pops out as merely being the operation for extracting the state of the subsystem from the state of the whole.

Yes, exactly, that is how the Born rule is regarded in any system in which the laws are the reality. But in any system where the observers are the reality, there is no such thing as an observer that is a "subsystem"-- the observer is there to tell you what is happening, not to be a part of what is happening that you are determining via some laws.

 

[Ken G]

Real experiments probe reality, but all that gives us is raw data. Learning requires us to analyze the data, and from the analysis, synthesize an understanding.

Here we must distinguish two types of "learning"-- there is a more "raw" type, which is like a child "learning" that things fall by repeated experience of the perception of things falling, versus the "learning" of a student in a physics class, who is using abstract reasoning to develop mathematical skills. The child learning that things fall is only noticing a consistency of experience, that will later be compared with the consistencies of other people's experiences, to develop a concept of what is real (versus what happens in dreams, etc). This does require mental effort, but not rationalism. The second type of learning, the learning of the postulates of a theory, is more like how we might learn the rules of chess, or the Peano axioms of arithmetic, or the capitals of the countries in Europe. These are all abstracted from the more "raw" elements of experience.

Now, I will grant you that "levels of abstraction" is an awkward concept. The rationalist, who prefers unified concepts, might be tempted to say that any abstraction is an abstraction, there are no "levels." Empiricism must allow levels of abstraction though, it is central to their axioms. It is certainly the core paradox of empiricism that a perception be regarded as more reliable than a postulate of a theory, when interpretation of perceptions themselves involve some kind of identifiable axiomatic system. But the axioms are simpler and more straightforward, more accessible by anyone, they look like "a consistent perception is real", not "systems evolve via the Schroedinger equation."

On the other hand, the rationalist is not free of pesky paradoxes either-- for when they follow a logical thought process, are they not perceiving their thoughts in their minds? How then can you talk about a "closed system", is not your brain an open one? If the closed system includes perceptions that you are not having, why can it not also include thoughts that you are not having, that seem just as valid to the perceiver of those thoughts as yours do to you? So any logical proof that the postulates are working that you could offer might be countered by a logical proof that they are not working, offered by some other brain in the closed system. You end up having to treat yourself as a god one way or the other-- either you assert that your perceptions decide what is real, or you assert that your reasoning decides what is true. But you are just a subsystem, so neither way can you really say that you speak for the closed whole, unless you simply take it as an axiom that you do.

 

[Eqblaauw]

poll update, I asked the following question to eminent physics , none of which I knew their ideas in advance:

a: I subscribe to the MWI that contains many parallel universes that differentiate during every 'quantum event' (meaning that there are many perhaps an infinite number of copies of everyone that inhibits earth)

b: I subscribe to the MWI that contains many parallel universes that split during every 'quantum event' (meaning that there are many perhaps an infinite number of copies of everyone that inhibits Earth constantly being created)

c: I don't subscribe to a or b, because I think they are both false

d: I don't prefer any of the above

First some remarks
-2 said c/d, those where counted c 1/2, d1/2,
-one said I can't do anything with the poll, cause this has no empirical evidence and therefore has nothing to do with physics,
to avoid all accusations of being biased I didn't count him,
-one said c with a minor change, I don't subscribe to a or b,
to once again avoid all acusations of being biased I didn't count him in,
-one said I don't like both descriptions a or b, to me mwi just means unitary evolution but I chose b,
to avoid all accusations of being biased I did count him as b,
-one sais a,but with a very weak meaning of parallel meanings 'existing' (I don't really know what he means)
but once again to avoid being depicted as biased I counted him as a
- one said d, he didn't thought that a,b captured the good things about mwi, I will count him as d since this poll is about the versions that Max Tegmark and David Deutsch and the likes subscribe to, but if you want to count him as a mwi-er, then you're free to do that, although that isn't really clear from his post . I think it's save to say that no-other (c's) or (d's) where subscribing to any mwi with parallel universes that wasn't mentioned in the poll, because they where free to say so. But there is an iny miny chance These where the answers

C: 15
D: 6
A: 1
b: 1

the reactions came from (I promised to not make their names publicly, but since I don't mention who voted what, I don't think there is any harm in it):
David spergel, Carlo Rovelli, David polizer, David Finkelstein, Richard Muller, M.J. Rees, George F Smoot the Third, Goldreich, James Daniel Bjorken, Richter Burton, John Preskill, Leon N. Cooper, Robert Wald, James Binney, Yakir Aharanov, Andy Fabian, Ulrich Becker, Jim Al-Khalili, Frank Close, Frank Wilczek, Rodolfo Gambini, Jorge Pullin, John Baez.

 

[faen]

I haven't had time to read through this thread, but I am surprised that not everybody realize that MWI is bullocks. There is simply no reason to assume that many new universes are created, more than believing in Santa Clause.

It seems as if the theory is created in order to explain why other quantum states weren't chosen. It says that the other quantum states are the ones which are chosen in another universe. However what really happens with the non chosen quantum states is that those which aren't entangled with the measurement instrument, become entangled with other parts of the environment. Thus no more dimensions, or universes are required to explain what happened to the other quantum states, since they become entangled to the environment and not other universes.. Anybody disagree??

 

[kith]

It seems as if the theory is created in order to explain why other quantum states weren't chosen. It says that the other quantum states are the ones which are chosen in another universe. However what really happens with the non chosen quantum states is that those which aren't entangled with the measurement instrument, become entangled with other parts of the environment. Thus no more dimensions, or universes are required to explain what happened to the other quantum states, since they become entangled to the environment and not other universes.. Anybody disagree??

Yes. What does get entangled is the state of the system with the state of the measurement device (you don't need an additional environment). How is this superposition separated? Is the corresponding porcess unitary? Please provide a reference or at least a mathematical sketch of your idea.

In the framework of open quantum systems and decoherence, you start with a pure superposition state for your system. Due to interactions with the measurement device, it evolves into a mixed state. This by itself doesn't explain why exactly one eigenstate is chosen in a measurement. It just shifts the measurement problem from superpositions to mixed states.

 

[faen]

Yes. What does get entangled is the state of the system with the state of the measurement device (you don't need an additional environment). How is this superposition separated? Is the corresponding porcess unitary? Please provide a reference or at least a mathematical sketch of your idea.

In the framework of open quantum systems and decoherence, you start with a pure superposition state for your system. Due to interactions with the measurement device, it evolves into a mixed state. This by itself doesn't explain why exactly one eigenstate is chosen in a measurement. It just shifts the measurement problem from superpositions to mixed states.

Ok i realized now why the MWI is supposed to solve the measurement problem. I didn't see that that was the intention of MWI when i wrote my previous post..

However i still disagree with the MWI. Let's say you have a system that can get entangled with the environment.. Then a system of n eigenstates can become entangled to the environment in n! ways or something. I'd say this complication reduce the probability of a system that creates new worlds, since it must in addition be aware of all the n! possibilities. Or why would it not take into account the n! possibilities...? Then it would again be random which combination of distribution within the environment it chooses.

Anyway, my belief is that quantum mechanics is an incomplete theory and that the basic steps of actions in this universe is self contained.

 

[Ken G]

Let's see if we can get general agreement that MWI is the only possibility if the Schroedinger equation is the sole description of physical time evolution, and the measurement problem is interpreted as an issue about how to characterize open substates (like observers) as something separate from the time evolution of the closed whole. Can we agree with this? That was never my problem with MWI, I accept that MWI is the way to go if you base everything on that single postulate about closed systems.

My issue is that the way we arrive at this postulate about closed systems is by opening them, by measuring them. We'd have no idea the postulate was true if we couldn't do that. So trying to relegate the act of measurement into some dusty corner of the full evolution of the closed system doesn't ring true to me-- physics is what we can say about nature by doing science, so is fundamentally about opening systems and making a subject/object separation when we do that. There is no such thing as physics without that, so it is not allowed to be viewed as some minor detail living inside some more prevailing rationalistically described time evolution from the "god's eye" perspective.

For this reason, CI adds another postulate to the Schroedinger-controlled evolution of closed systems-- it says that the concept of a closed system is just a concept, and fundamentally it is information about closed systems, obtained by opening them, that is the heart of physics. As such, we also need the Born rule, at the same level of priority as the Schroedinger equation, because neither has any empirical meaning without the other. This approach requires that we regard definite outcomes as real, and forces us to adopt whatever additional postulates allow us to do just that. This is CI.

Now, for completeness, we can make a different choice for the added postulate, as done in deBroglie-Bohm. Here, the Born rule is not viewed as being at the same level of priority as the Schroedinger equation, but something else is-- the hidden variables locked up in the initial conditions. These hidden variables mean that the wave function represents incomplete information, and so does the unitary evolution of the wave function, because there is information in the initial condition that actually determines what happens, completely. The Born rule is then seen as our own statistical treatment of what we don't know about the initial condition, just like how you'd treat your opponents' cards in a poker game.

So the differences in MWI, CI, and deBB-B are none other than different interpretations of the meaning of the Born rule. They all use the Born rule and the Schroedinger equation in exactly the same ways, so none of them are any more falsifiable within QM, but each one might be the way to go with the next theory. Personally, I'm fine with having all three at one's disposal, we should just view each as seeing QM from a different angle, like looking at an elephant from all sides. My only objection is taking seriously the "world view" that these interpretations can suggest.

Since CI really doesn't do that, I prefer CI-- MWI seems to suggest a world view where there really are this dizzying number of other worlds, and deBB-B seems to suggest a world view where the past really does completely specify the future in a deterministic way. I say, physics theories are not intended to spawn world views in the first place, because none of them are likely to be correct enough for their literal interpretations to be authoritative about such matters.

 

[kith]

Let's see if we can get general agreement that MWI is the only possibility if the Schroedinger equation is the sole description of physical time evolution, and the measurement problem is interpreted as an issue about how to characterize open substates (like observers) as something separate from the time evolution of the closed whole. Can we agree with this?

What about the ensemble interpretation? There, the time evolution is also exlusively governed by the Schrödinger equation.

 

[Fra]

To assert that "observers are quantum systems" is a fundamentally rationalist approach, you are saying that observers are ruled by a theory. That's not empiricism, observers are never "ruled" by anything, they are the definers of truth. No theory ever "rules" nature in empiricism, theories are invented by physicists to understand observations. Thus, no observer can be ruled by a theory

In here lies the same paradox I think was mentioned before, and I think it's clear what we have here.

The paradox is

1) on one hand to insist on the empirist observer perspective, in line with the sound science

2) and on the other hand to require that the laws of physics are observer are seen the same to all observers, thus we seek to formulate the covariant transformations.

Both seem reasonable at first sight.

The paradox is that there is no empirical status on the information about the covariant transformation rules that are generally valid. It is valid ONLY for subsystem.

Either you adopty a form of structural realism, that denies (1) when it comes to "laws of nature", but it applies to observations (according to laws) - thus you can imagine that it applies to the universe as a whole (except of course there is no empiricla support!), or you rephrase (2) into a more empirist formulation like Ithink I did ealier in this thread that (2) is replaced by negotiated democratic observers and the laws of physics are not a constraint but rather a result of negotiation. This is another way to resolve the paradox.

/Fredrik

 

[Ken G]

What about the ensemble interpretation? There, the time evolution is also exlusively governed by the Schrödinger equation.

Yes, that's another option, but there it assumes incompleteness right from the start. So we should say that MWI is the only interpretation that claims to have a complete description that is based entirely on the Schroedinger equation as the law of all time evolution of closed systems, including those containing observers.

 

[Ken G]

or you rephrase (2) into a more empirist formulation like Ithink I did ealier in this thread that (2) is replaced by negotiated democratic observers and the laws of physics are not a constraint but rather a result of negotiation.

Or what may have a similar spirit-- we say that laws of physics are examples of whatever keys we can find under the streetlights.

 

[Fra]

we say that laws of physics are examples of whatever keys we can find under the streetlights.

Note sure if I got that metaphor.

To me the key here is interactions in between observers. Laws are somehow the consensus that observers can agree upon.

The difference is wether they HAVE to agree at all times, or wether the agreement is emergent. Before it has emerged, the state of law itself is dismissed into the same "black box" as is the system for which the theory was formulated.

What is the key for me is the democratic process or the negotiation, not possible equilibrium points for such process.

/Fredrik

 

[Eqblaauw]

Einstein has (in my eyes) a wonderful quote:
I don't believe in math, As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality
It doesn't in itself reject the mwi but I think it's a good medicine against some of the thinking of mwi-ers. It surely is a good medicine against 'mathematical universe' of tegmark, and of course all possible universes do exist, just like it is impossible that I ate a large apple pie this morning, the question scientists should be asking is which universe(s) are possible, and you don't do that by making some formulas that are consistent and saying: hey look at this, this is all possible.
Also, I don't imagine that the brightest mind in the world, that's for some reason death blind mute and only read (with his/her fingers) all the pure math books in the world, could ever come up with e = mc2

 

[Eqblaauw]

Tegmark says all consistent mathematically correct universes exist
to know if this has any meaning you can ask yourself the question: consistent with what?
-with itself
that really hasn't got any meaning at all, if it hasn't got any observation to verify it,
when there are observations, then you can see if it's consistent with the universe (or multiverse for that matter).
This mainly is against mathematical universes by the way.

R.I.P. Popper

 

[Eqblaauw]

poll update, (sorry to copy the earlier message with changes, but I somehow couldn't edit it) I asked the following question to eminent physics , none of which I knew their ideas in advance:

a: I subscribe to the MWI that contains many parallel universes that differentiate during every 'quantum event' (meaning that there are many perhaps an infinite number of copies of everyone that inhibits earth)

b: I subscribe to the MWI that contains many parallel universes that split during every 'quantum event' (meaning that there are many perhaps an infinite number of copies of everyone that inhibits Earth constantly being created)

c: I don't subscribe to a or b, because I think they are both false

d: I don't prefer any of the above

First some remarks
-2 said c/d, those where counted c 1/2, d1/2,
-one said I can't do anything with the poll, cause this has no empirical evidence and therefore has nothing to do with physics,
to avoid all accusations of being biased I didn't count him,
-one said c with a minor change, I don't subscribe to a or b,
to once again avoid all acusations of being biased I didn't count him in,
-one said I don't like both descriptions a or b, to me mwi just means unitary evolution but I chose b,
to avoid all accusations of being biased I did count him as b,
-one sais a,but with a very weak meaning of parallel meanings 'existing' (I don't really know what he means)
but once again to avoid being depicted as biased I counted him as a
-one didn't see a difference in a or b, but chose b because he thought the word 'split' was better (I now have added that in b you multiply as do universes, and c you already exist in many universes, but I think the description itself wasn't incredibly vague)
- one said d, He does however subscribe to the Everett relative state interpretation, and does think that all possible universes exist in 'some sense'
maybe some tiny percent of the (c's) or (d's) where subscribing to any mwi with parallel universes that wasn't mentioned in the poll,
But I think it's very unlikely (since I think the logical thing would be to make notice of that) These where the answers

C: 18
D: 7
A: 1
b: 2

the reactions came from (I promised to not make their names publicly, but since I don't mention who voted what, I don't think there is any harm in it):
David spergel, Carlo Rovelli, David polizer, David Finkelstein, Richard Muller, M.J. Rees, George F Smoot the Third, Goldreich, James Daniel Bjorken, Richter Burton, John Preskill, Leon N. Cooper, Robert Wald, James Binney, Yakir Aharanov, Andy Fabian, Ulrich Becker, Jim Al-Khalili, Frank Close, Frank Wilczek, Rodolfo Gambini, Jorge Pullin, John Baez. Donald Lynden-Bell, Rafael D. Sorkin, Mark Sredniki, Warren Siegel

the people that had extra comment and chose c said the following things:X1:

I think the many worlds interpretation is nonsence.
It does not survive Occham's Razor.

!me! when asked what his response was to mwi-ers answer <Occam's razor actually is a constraint on the complexity of physical theory, not on the number of universes. MWI is a simpler theory since it has fewer postulates> he said (I don't understand it, but I think some will) !me!

X1:
Any theory that predicts enormous numbers of copies of the universe
none of which are directly observable is introducing a huge
redundancy for explaining one small effect. That to me is quite wrong
and disobeys Occham's razor. It is easier to imagine that our concept
of a particle or a quantum are wrong in some way. There are already hints
of this from such matters as the spectra of diatomic molecules which
are radically affected by whether the nuclei are identical or not.
If as in Oxygen the nuclei are the same and of spin zero then every
other line in the rotational spectrum of the molecule is missing!
How does the molecule know its tiny nuclei are identical?

X2
Sure, my answer is definitely "c". I do not think that MW is good or
useful, in any variant.

X3
The many-worlds theory is a silly mistake, mistaking possibilities for actualities. It comes from the attempt to deny the statistical meaning of psi vectors
and regard them as real things, present in the individual system; and nevertheless to avoid the mistaken theory of "collapse" that such reification originally led to.
The theory that people actually use has one world, no collapse, transition probabilities, and incomplete descriptions.

X4
NO TO MWI

X5
My best answer is c. The theory is false because it is inconsistent.
a c/d vote said he considered it a argumentum absurdum, that we lack knowledge and he would have voted c if it not contained the phrase 'both false'

one d said: If a parallel universe is unobservable even in principle, then it's meaningless, according to established scientific method.
"Meaningless" means it's neither true nor false, since it's untestable

 

[Ken G]

Note sure if I got that metaphor.

The idea that the laws should be the same for all observers is not a law, it is a standard for laws. It is instructions for where to look for them, which makes them easier to find-- like a streetlight. It also says to look for laws that have a particularly "democratic" element, and to not consider as a law anything less. Note it is not falsifiable, so it is not itself a law.

Now wait, you say, of course relativity is falsifiable. But that's just any particular brand of relativity, like c being constant. Saying that the laws must be the same for all observers just means that if they only work for a subset, look for different laws that are the same for all-- that isn't falsiable. Physics went 2 centuries being content with laws that only work for inertial observers (it's obvious that F=ma is only a law for them), so it's a rather new standard, and we only adopt it because Einstein showed us we could. Einstein "found the keys in the streetlight", and asserted that we should always look for them there because it is easier to find them when you know where to look, and they are the kind of keys we are looking for.

To me the key here is interactions in between observers. Laws are somehow the consensus that observers can agree upon.

Yes, I agree this is the key. There would be no such thing as laws without observers, that's the part that rationalists don't like, and it's what MWI must reject.

What is the key for me is the democratic process or the negotiation, not possible equilibrium points for such process.

The road rather than the destination? Certainly sounds like an apt metaphor for science.

 

[Eqblaauw]

Dear mwi-forum participants,
the poll is closed, I've deleted my account, and there by any direct evidence of the poll, though everything I mentioned can be verified by the people mentioned,
if you want to use this poll for wikipedia or other sources you're free to do that,
I will vouch for that this poll is fully honest, and I also vouch for the statement david raubs poll most likely isn't.
I conducted the poll under the name 'Gertjan Kouweheuve' because I didn't wanted that any of my posts elsewhere would influence the poll. That's the only lie I permitted myself to, with this poll.
This also will be, if I can resist to login somehow, the last post I'm going to submit on this forum (physicsworld).
and as we say in some parts of holland 'houdoe!
Edo Blaauw

 

[nazarbaz]

Not necessarily. We don't have to choose between either saying that there is no "progress" in science, or that the ultimate goal is a "TOE." I don't think either of those views have much of a clue about the progress of science as it has been, and I don't see any reason to expect the progress of science to change suddenly now. Instead, I'd say these lessons of the history of science are pretty hard to deny:
1) scientific progress looks like gradually improving accuracy achieved by radically different ontological pictures, and
2) every generation thinks their own ontological picture is "on the right track", regardless of how completely it differs from previous ontological pictures.
Given these two seemingly uncontroversial facts, I think we can conclude that scientific accuracy converges, but scientific ontology does not. The main problem with postmodernist science is that it is generally not done by scientists, but it does have some useful "cautionary" remarks to make, as you say.

If we assume that scientific progress does exist, we must infer that our actual theories are effectively closer to the right picture than the previous ones (how close is a different question). In the history of science, there is both nicks and continuities.
The continuity is not an inner quality of the scientific effort, it's always super-imposed by rationalizations. The sociology and the factual development of science is misleading in that respect. We need to do the job and never expect to find it ready to use.

 

[Ken G]

If we assume that scientific progress does exist, we must infer that our actual theories are effectively closer to the right picture than the previous ones (how close is a different question).

Actually I would argue, as pertinent to MWI, that this is precisely what we can not infer. Making scientific progress does not require, and probably does not even suggest, that we are getting "closer to the right picture." I say this for three reasons:
1) scientific progress is always measured in terms of the increasing power it gives us over our environment and the increasing accuracy in our predictions, never by how right our picture is,
2) the pictures change so dramatically with each increment of accuracy and predictive power that no convergence of the "pictures" is in evidence, and there is also no direct connection between how much the picture changes and how much the accuracy improves,
3) there is no scientific evidence whatever that there is any such thing as "the right picture" that we could be moving "toward" in the first place.
These are important facts to bear in mind, because otherwise we fall victim to the same kinds of unjustifiable conclusions we turn up our noses at in pseudo-scientific endeavors.

 

[eqblaauw2]

If we assume that scientific progress does exist, we must infer that our actual theories are effectively closer to the right picture than the previous ones (how close is a different question). In the history of science, there is both nicks and continuities.
The continuity is not an inner quality of the scientific effort, it's always super-imposed by rationalizations. The sociology and the factual development of science is misleading in that respect. We need to do the job and never expect to find it ready to use.

I'm sorry but this must be one of the biggest pieces of crap I have ever read.
The newest theory (because at this moment I came up with it) is that the universe is a game played by Crocodile Harry, who has an Oedipuscomplex, and bad teeth.

I do however think a poll can indicate what the sciense community generally thinks at a certain moment, and that what the sciense community thinks generally is more correct then what the sciense community thinked in the past. However at this point the newer theory (MWI) isn't a populair theory at all (as I think I succesfully demonstraded). If and this is a big if, because I think if you do some reliable research you will find that there are other interpretations still more populair then MWI, MWI is the most popular theory that also doesn't mean it is a populair theory since the majority clearly rejects it. Then the most populair idea would be we don't know. But again this is an if, because the MWI theory isn't that populair at all (more populair then you would think at first notice when you read the rather extreme point of view, but still not close to being populair).

P.s. sorry that I couldn't resist login in again, but I really hate ********

 

[eqblaauw2]

I must say I quess the only positive thing of mwi for me is it really made me appreciate more my believe that everyone is unique, and that I'm mortal (if you really think about it being immortal is far more worse then being immortal, although that isn't nice either). And of course that I have made a reliable poll that may have helped people.

 

[BruceW]

However at this point the newer theory (MWI) isn't a populair theory at all (as I think I succesfully demonstraded). If and this is a big if, because I think if you do some reliable research you will find that there are other interpretations still more populair then MWI, MWI is the most popular theory that also doesn't mean it is a populair theory since the majority clearly rejects it. Then the most populair idea would be we don't know. But again this is an if, because the MWI theory isn't that populair at all (more populair then you would think at first notice when you read the rather extreme point of view, but still not close to being populair).

Many of the interpretations have several different possible meanings (MWI in particular). So a survey of the preferred interpretation is not very useful.
In most textbooks, CI is stated as the most standard interpretation, and in most situations CI is the easiest to understand. So for these reasons, I would guess CI is the most popular.

 

[Ken G]

The poll did refute claims that MWI has transitioned into the most popular interpretation, often cited as a consequence of better understanding of decoherence. I've tried to stress that this argument stems from an incorrect placing of "collapse" into opposition with "decoherence", when in fact the correct relationship is "decoherence sets the stage to interpreting collapse, whichever interpretation of collapse is used." CI works just fine in a "decoherence leads to collapse" framework, it was never one or the other.

Also, I still say that bashing interpretations is kind of silly, because all interpretations do is give us a new angle with which to look at our theory. We can bash the taking of an interpretation literally, to the point of using it to draw conclusions about how reality actually works, but that's not bashing the interpretation-- it's bashing what the interpretation is used to do. That's what I mean by creating a "world view" from MWI, and I think the history of science is all too clear on the pitfalls of doing that, even for interpretations not nearly as bizarre as MWI.

 

[eqblaauw2]

Many of the interpretations have several different possible meanings (MWI in particular). So a survey of the preferred interpretation is not very useful.
In most textbooks, CI is stated as the most standard interpretation, and in most situations CI is the easiest to understand. So for these reasons, I would guess CI is the most popular.

read the poll (it's on this forum), read it again if nessasary: it's offering a clear insight that probably the mwi's that are mostly advocated (including Bryce de Witt's, who really for the first time actually 'made' the mwi, and I think thereforethat his version would be the best way to refer to mwi) (with it's consequenses) aren't that populair at all among scientists. Also I got 6 reactions (one I didn't mention in the poll) which also got clear refutations of ANY mwi at all (and perhaps it isn't really relevant this includes a recent nobel laurate, and if I'm not mistaken one older nobel laurate, but I deleted the mail adress so I can't vouch for that) . And I'm sorry but I assume these aren't the only ones in the poll who voted c who rejected any mwi, because the people that did mention this did this while this wasn't itself being asked , actually I think it's most likely the majority did. And very most likely almost everyone rejected the copies idea. That being said 6 already is already more percentage wise then david raub's poll, but that I think isn't really relevant because of the very logical conclusion that in the randomly (only because of there reputation selected) participants in the poll reject MWI.
So this poll is in my opinion (and this opinion is so logical I don't think you can succesfully refuted) is relevant if you want to know what phycisists who think a lot about quantum mechanics think.
So please stop putting mist on very clear things. Also I must say I agree with Ken G's beginning of the post.
And I'm serious, it may sound a bit harsh, but will you (and I mean everyone on this forum) please stop posting things that just don't make sense (not because it's against my own personal opinion, but just because it doesn't make sense, and confuses people, you can of course advocate every opinion you like) so I don't have to come back here and post obvious posts again and again.

 

[kith]

This poll is nonsense.

First of all, your options are very poorly defined. An interpretation of a physical theory is always an interpretation of mathematical objects and their relations. So in order to get useful options for a survey, the first step is to present a generally accepted mathematical formulation of the theory. The second step is to choose different -well-known to be consistent- ways to interpret the mathematics in physical terms. And the third step is to draw conclusions from these interpretations.

You only did the third step, which of course is not do-able in a satisfactory manner if you skip the first two. So you chose two popcultural statements which have something to do with the MWI, and added the options to contradict them or be indifferent. How shall such a survey be able to produce reasonable results?

Plus, your survey is not at all representative. Why do you think these 30 people represent the physics community?