Revisiting the Completeness of Quantum Theory: A Scientist's Perspective

[imiyakawa]

The fact that QM cannot yield accurate measurement predictions is the proof of QM incompleteness. Incompleteness doesn't mean a new theory is left. It only means that QM cannot explain/predict the nature we observe. It can explain part of it, but not the whole of it. So, it is logical to say that it is incomplete.

Heisenberg principle is telling us what is the empirical part that nature can render but QM cannot. Accepting Heisenberg principle is accepting that QM is incomplete..

The automatic corollary isn't incompleteness. Ceteris paribus, forgetting future discoveries, and assuming a random interpretation;
A. acausality, then QM is complete.
B. not-acausality, QM is incomplete if universe has causal closure.

 

[ConradDJ]

The description of this process, by which this new information is added to the system, is unknown and unknowable (according to Bell and Aspect).

So, the process exists in nature, but the theory that describes it will never exist. So, again, theory doesn't reach nature and won't ever...

Am I wrong concluding that ...?: Einstein was right: Nature can do it, QM cannot.

Well, even apart from QM, in classical physics -- three massive bodies can move under the influence of their mutual gravitation, but Newton's equations only describe the motion of two gravitating bodies. There is no equation that can (without approximation) predict the motion of three bodies. I'm not sure that means the theory is incomplete or in any way inadequate. Certainly nature can do a hell of a lot that mathematics can't.

 

[ConradDJ]

In Shannon's Information Theory, concepts of information and entropy are defined for random variables. What is the meaning of information about a system?

Rovelli does build directly on Shannon's theory. He thinks of "information about a system" as a series of yes-no questions that can be "put to the system" by another observing system. What that means exactly raises the complex question about all the different parameters that physical systems have and all the ways each of them can be measured... which he specifically avoids.

Here's the link if you're interested --
http://arxiv.org/abs/quant-ph/9609002v2"

 

[GeorgCantor]

If materialism, how do we know that the whole is greater than the sum of its parts? Who are we to say that ostensible self-organization at the "higher" levels isn't run by strict laws at the base of reality?

What is the base of reality you speak of? Me, you, bits, hologram, god, relations, master equation, fields,...? There is not much left for a base of reality after GR. Do you hope to deduce everything we observe from there? Are you going to deduce "the base of reality" from some other more basic laws, and the laws from other laws, that in turn would come from other laws...?

Even if something like Navier-Stokes fluid dynamics can't be deduced from our current host of 'base' formalisms, do we really have to infer "greater than the sum of its parts"?

What i implied was not a specific case of unexplained behavior, but the impossibility to tell why intrinsic quantum randomness manifests as seemingly deterministic patterns on the macro scale(this is concerning the whole of reality, the entire universe, not a specific phenomenon).
Can you answer why intrinsic quantum randomness translates into outcomes that preserve determinism and causality within the same FOR? I.e. why doesn't the HIV virus materialize into my bloodstream if i sit close to a HIV-sick person(an unmeasured HIV virus isn't well localized)? Or if you believe in decoherence, why doesn't it decohere in the blood of a person sitting somewhere close by? QM's indeterminancy says it's possible but it's never been observed to my knowledge and lhv models are refuted. There is either a non-local(and very possibly non-realistic) underlying reality(what you refer to as "base of reality") or reality is simply hollistic. As a side note, non-local and non-real underlying reality is the other name for mind(information).

It would just mean that either we don't have all the base laws figured out yet, or there's laws that 'kick in' at the higher levels, perhaps interference of self-gravitation onto the system that isn't seen on the singular wavefunction level.. Maybe I'm being tripped up on what you mean by "whole is greater than sum of its parts".

The laws that "kick in at higher levels" is exactly what i was talking about. This is a good description of what a hollistic reality is about.

And, assuming a non-local hidden variable interp. is false, why does random collapse to discrete-state give credence to the notion that the whole is > the sum of its parts?

Where do the determinism and causality on the macro level come from? Or are you one of those guys that believe that electrons have a well defined position and momentum at the same time and it's guided by a non-local pilot wave to a deterministic picture of laptops, TV's, chairs and tables?

 

[imiyakawa]

The laws that "kick in at higher levels" is exactly what i was talking about. This is a good description of what a hollistic reality is about.

Good, we are in conceptual agreement. We are in agreement that this type of reality is possible. We aren't in agreement about the level of a priori certainty that should be invested in this reality.

Are you going to deduce "the base of reality" from some other more basic laws, and the laws from other laws, that in turn would come from other laws...?

My position is "I don't know". This may be the case, it may not be. We don't know.

I just had trouble with the saying "whole greater than sum of its parts". If you define this saying as your "hollistic" reality, then we are in agreement that the preceding saying may or may not be correct. I was operating under a different definition of that saying than you were.

My second concerd was with the certainty of your exposition.

Where do the determinism and causality on the macro level come from?

I don't know.

Your main premise was "Reality simply is, it can't be reduced from the fundamental interactions" which is what I had trouble with; I just don't see how you can be certain.

Where is your certainty sourced from? The quantum/classical threshold? The potential for an infinite regress down the rabbit hole of finding laws that govern smaller and smaller units? Hmm

My friend is a physicist and he holds a completely opposed view. Is he wrong and you correct?

I'm going to remain ambivalent on something we cannot know.

There is either a non-local(and very possibly non-realistic) underlying reality(what you refer to as "base of reality") or reality is simply hollistic.

Precisely. We are in utter agreement of the two possibilities. My questioning of your post was simply me expressing anxiety at how you could be so sure the latter was true (also, if you define "whole > sum of parts" as a hollistic reality, then I'm NOT debating against you, we're talking about different definitions). I never said it wasn't. I'm saying we don't know at present.

why doesn't the HIV virus materialize into my bloodstream if i sit close to a HIV-sick person(an unmeasured HIV virus isn't well localized)? Or if you believe in decoherence, why doesn't it decohere in the blood of a person sitting somewhere close by? QM's indeterminancy says it's possible but it's never been observed to my knowledge and lhv models are refuted.

Are you asking why their blood doesn't collapse into your body? I see why you brought this up.

Apeiron's global constraints!

This doesn't suggest the whole being greater than the sum of its parts. Are you saying something other than:

a non-local underlying reality

is governing this system [i.e. the reality is "hollistic"]? How do you know?

If you're not saying this, then you can shift from the laws governing the system and say a complex system is greater than the sum of its parts through its interactions. I'm not debating this. I was assuming that when you said "whole > sum of parts" you meant reality IS hollistic and isn't a slew of "base" laws that interact to produce complex systems.
---------------------------------

All in all, I was debating:
- the definition of "the whole being greater than the sum of its parts" as what you call a hollistic reality. My position is it's too early to know whether or not higher level interactions can be predicted solely from NL base laws - assuming they even exist.
- the assertion that "it can't be reduced from the fundamental interactions".

I wasn't debating:
- "the whole being greater than the sum of its parts" under the definition of the parts + interactions, which is what your HIV scenario supports.

 

[GeorgCantor]

All in all, I was debating:
- the definition of "the whole being greater than the sum of its parts" as what you call a hollistic reality. My position is it's too early to know whether or not higher level interactions can be predicted solely from NL base laws - assuming they even exist.
- the assertion that "it can't be reduced from the fundamental interactions".

I wasn't debating:
- "the whole being greater than the sum of its parts" under the definition of the parts + interactions, which is what your scenario supports - however it doesn't yet support hollistic vs. litany of NL fundamental laws (if they exist), which is the only thing I had trouble with.

Then let's word it differently - "The whole is definitely more than the sum of its parts(as we know them now)".

I have very severe conceptual difficulties believing that ALL of our observations(incl. mind) will be explained within the framework of causal interactions in a "universe" where spacetime is not a fundamental concept and where the "stuff" is a non-local energy-wave 'thing' that doesn't have fixed properties across different inertial frames.The uncertainty principle, which i take to be a fundamental postulate of qm, is a very grave obstacle as well.
But since this is the philosophy forum and a deeper perspective is sought, you are right, my opinion is a reflection of the current knowledge so it could be wrong in the very long run. It does seem to me like a very well motivated and argumented opinion(as of NOW!) and it would be a good idea to ask your friend why he believes what he does. Perhaps he has a vision(interpretation) of reality that is very different from anything i have met, read or thought about so far.

 

[computerphys]

The automatic corollary isn't incompleteness. Ceteris paribus, forgetting future discoveries, and assuming a random interpretation;
A. acausality, then QM is complete.
B. not-acausality, QM is incomplete if universe has causal closure.

Assuming option A, I don't get how you reach at the conclusion that QM is complete.

(Of course, I discard option B due to debunked hidden variables.)

Filling the gap left by uncertainty principle with acausality doesn't change the fact that there is a gap and it is not filled with QM.

If we have a glass of water with a leak at the upper side, it becomes impossible to fill it completely (at equilibrium). Can we say it is completely filled when there is air instead of water in the upper part of the glass due to the leak?

I think correct expression for that case is saying that the glass is not completely full of water and it cannot be completed in any way. I don't know if I am expressing correctly this simile.

 

[GeorgCantor]

My position is "I don't know". This may be the case, it may not be. We don't know.

Something tells me you don't believe it will one day be possible to recover your "self"(the "I") somewhere among the non-local energy-wave manifestations whose actualities appear to be dependent on the environment and the observations you take on them.

As far as i can tell, it's a self-referential loop and it'd be naive and ignorant of me if i were hopeful that we'd one day explain everything.

It's too late where i am, i will come up with examples tomorrow where Nature appears as if it tries to 'hide' its secrets.

 

[computerphys]

Well, even apart from QM, in classical physics -- three massive bodies can move under the influence of their mutual gravitation, but Newton's equations only describe the motion of two gravitating bodies. There is no equation that can (without approximation) predict the motion of three bodies. I'm not sure that means the theory is incomplete or in any way inadequate. Certainly nature can do a hell of a lot that mathematics can't.

1.- N-body lack of integrability is a limit of mathematics.
2.- Heisenberg principle is a limit of physics.

I think it would be right to say that case #1 implies that integral calculus is incomplete, and correspondingly, case #2 implies that QM is incomplete.

 

[computerphys]

I have just found out that there are 3 possible senses about the concept of completeness:

A complete theory describes:

1.- all there is to say about nature (Shimony)
2.- all elements of reality (Einstein's EPR)
3.- all outcomes of experiments (Ballentine and Jarretts, "predictive completeness")

A complete glass of water is:

1.- that full of water up to the highest place you can
2.- that full of water up to the top of your concept of glass
3.- that full of water up to the top of the glass you can observe

Is that simile correct?

 

[imiyakawa]

I have very severe conceptual difficulties believing that ALL of our observations(incl. mind) will be explained within the framework of causal interactions in a "universe" where spacetime is not a fundamental concept and where the "stuff" is a non-local energy-wave 'thing' that doesn't have fixed properties across different inertial frames.The uncertainty principle, which i take to be a fundamental postulate of qm, is a very grave obstacle as well.

I haven't actually thought of those points. Thankyou.

I do have great conceptual difficulties with the mind, as well. That's what I spend all my time reading/thinking about :). However I never meant to express skepticism with the assertion "whole > sum of parts" with reference to seemingly anomalous properties/phenomenon. All I meant to express skepticism to was the idea that both a hollistic reality exists and some of the laws won't be able to be deduced from some base TOE (which you think is a silly idea, and I am sympathetic to this view, but am not certain).

But since this is the philosophy forum and a deeper perspective is sought, you are right, my opinion is a reflection of the current knowledge so it could be wrong in the very long run. It does seem to me like a very well motivated and argumented opinion(as of NOW!) ... . Perhaps he has a vision(interpretation) of reality that is very different from anything i have met, read or thought about so far.

First, his focus is deBB which will explain a lot. But even without that, his views are that there may be this hollistic reality you speak of but the laws that kick in at higher levels will be able to be deduced from a slew of laws laid out from observations of the quantum, which is what I thought you were saying cannot possibly happen, but it turns out you weren't (you were just entertaining some skepticism).

And, ironically, he is working on higher level laws that "kick in" - the influence of gravitation on larger and larger systems of wavefunctions as a possible solution to N-S!

Something tells me you don't believe it will one day be possible to recover your "self"(the "I") somewhere among the non-local energy-wave manifestations whose actualities appear to be dependent on the environment and the observations you take on them.

Are you asking if I'm a materialist? Or are you asking if I think the consc=collapse interpretation is correct ("the observations you take on them.")?

Actually I think you're asking me if I think you can explain consciousness reductively. I doubt it. However, it must be remembered that irreducibility or reducibility are just layers of explanation - nothing extra exists on the level you pick, or if you pick many levels interacting. I prefer to say, if materialism, consciousness IS [pick a particular set of interactions, or whatever the 'mechanism'] rather than consciousness "results from".

 

[imiyakawa]

A complete theory describes:
1.- all there is to say about nature (Shimony)
2.- all elements of reality (Einstein's EPR)
3.- all outcomes of experiments (Ballentine and Jarretts, "predictive completeness")

Nice.

Filling the gap left by uncertainty principle with acausality doesn't change the fact that there is a gap and it is not filled with QM.

Assuming we've formulated QM fully, and assuming randomness is acausal;
I'd disagree with this. I think our QM is complete because it's saying all it can say about nature (it's acausal), and it's getting the most exacting outcomes of experiments possible.

If QM predicted anything other than randomess, the theory would be incomplete!

Although maybe you mean QM in this instance wouldn't tell us "why" it's acausal.

Well, if it DID try and tell us why THEN it would be incomplete, because acausal has no cause and so why cannot ever be answered. Or perhaps there will be some antecedent cause that allows for acausality. MM my brain is hurting I'm going to take a break.
(If the latter, you are correct, if the former, you aren't. Although, even if the latter, this QM formulation may be "complete" as far as this universe is concerned - if the answer required us to probe some precedent conditions not in this universe, then I think we could still call QM "complete")

 

[computerphys]

if it DID try and tell us why THEN it would be incomplete, because acausal has no cause and so why cannot ever be answered

I agree with you that QM is complete in the sense that it is 1.- all there is to say about nature (Shimony).

And I add that QM is incomplete in the sense that it cannot predict 3.- all outcomes of experiments (Ballentine and Jarretts, "predictive completeness").

It is clear that definition #1 is very anthropocentric because the criteria for completeness is about the possibility of science to say something more. Is it reasonable to state that the glass is full just because we are not capable of filling it more?

I think definition #1 is better suited for word "completable".

Quite the opposite, definition #3 is based on purely experimental facts. Is it unreasonable to say that the glass is incomplete because we see there is part of the glass still empty?

This all can be summed up in following statement: QM is incomplete and in-completable.

 

[imiyakawa]

Yes, you've summarized it quite well, I agree.

 

[apeiron]

This all can be summed up in following statement: QM is incomplete and in-completable.

QM could be looked at as the correct way of asking the questions of reality - of being an observer - but the scope of such questioning is inexhaustible. Reality can always tell us more.

Each question we ask imposes global constraints on what can exist at a spatiotemporal location. It narrows down the scope of what may be. So asking a lot of questions simultaneously can yield some fairly definite answers. However there is the Planckscale limit, the HUP. If we really get obsessed about an exact answer to one aspect of a system, such as its momentum, we lose sight of its other exactly dichotomous or complementary aspect, its location.

So it would seem QM is complete as a method for asking questions about locality. And it even models the impossibility of complete certainty about anyone aspect of measurement (asymptotic certainty about one aspect being accompanied by asymptotic uncertainty about its complementary aspect).

Thus it is really reality that is fundamentally incomplete here! Or vague, indeterminate.

The mistake is to think that things exist, that reality is fundamentally crisp. Rather, what we start with is a state of pure potential that gets shaped up into something firmer by the questions being asked of it - or rather, by the context of global constraints that bear down on a locale.

QM says reality needs to be constrained to be anything (as fundamentally it is free and could be anything).

Humans, creating experiments, can manipulate the prevailing state of the universe (macro-variables like temperature, diffraction gratings, polarising lenses, etc) and so as a matter of choice, relax or tighten some particular aspect of constraint. Humans can be particular observers.

But the universe (as a persistent system of constraint, a tightly woven history of events that becomes a prevailing context that dissipates local uncertainty) is the general observer. It is asking the most different questions at once, in homogenous fashion, and so maximises certainty for the greatest number of local observers.

Even the universe, as the generalised observer, cannot erradicate uncertainty. There is always still some small degree of the unmeasured, further questions that could still be asked, and so there is always some small degree of QM spontaneity regarding "what is happening".

But this uncertainty is constrained to the smallest scale (shortest distances/highest energies - note the dichotomy again).

Anyway, the two keys to understanding QM in systems terms are:

1) Reality is rooted in vagueness rather than crispness. Before there is the actual, there has to be the merely possible. A term like uncertainty implies hidden variables - the crisp states exist "down there", but we just haven't been able to measure them yet. The idea of indeterminancy, or better yet vagueness, says certainty is what we are creating.

2) "Observation" is needed to shape vague possibilities into crisply-taken actualities. But observation is nothing to do with consciousness as such, it is just about a tightening net of global constraints. The universe is a generalised observer in that it encodes (informationally, as a collection of particular histories, particular events) a generalised global state of constraint. There is a prevailing history into which anything new must fit. Humans then step on to this already created stage of dynamic constraint and can fiddle around in ways that change the prevailing balance. We can distort what the universe is doing in ways that give a glimpse of the more fundamental vague potential from which all things arise.

However, what is clearly missing from QM is that it is not a model of the observer. It is not a model of the universe as a global system of constraints. This is why other scientific discourses, like dissipative structure theory - which is a theory of global constraint - would seem to be a way towards a more unified perspective on things.

QM models the way local questions can be asked, and the limits that will be encountered. But it does not model the state of knowledge that arises in a system able to generalise across a vast number of "questioning events".

QM says this is how any question can be asked. Which is a usefully free way of looking at things from the point of view of a human scientist. But the universe is simply interested in crisply existing. So we need a larger model that includes the way that observers become constrained to see only the one general history (the history this observer is in fact making, so as to crisply exist).

 

[computerphys]

Thus it is really reality that is fundamentally incomplete here! Or vague, indeterminate.

* If you say that reality is fundamentally indeterministic then I agree with you. (This is IMO the reason why no theory will ever fill the gap left by uncertainty principle; the reason for all possible quantum theories being in-completable, now and ever)

* If you say that reality is fundamentally incomplete then I don't get why you say that. I don't even understand what the sentence "reality is incomplete" means.

* If you say that reality is vague then I disagree with you, because experimental outcomes are not vague, but accurate. It is quantum theory that is vague and inaccurate (statistical), but not reality. Let us recall Young's Double-Slit Experiment for a single particle. The impact of the particle on the screen is a pinpoint dot, not a fuzzy blob, isn't it? So, reality is accurate, but not vague.

In my opinion, due to the impossibility of QM to make complete predictions, we are tempted to conclude that nature is fuzzy like QM. But experimental outcomes are the proof that nature is accurate while QM is statistical and incomplete.

 

[apeiron]

* If you say that reality is fundamentally indeterministic then I agree with you. (This is IMO the reason why no theory will ever fill the gap left by uncertainty principle; the reason for all possible quantum theories being in-completable, now and ever)

* If you say that reality is fundamentally incomplete then I don't get why you say that. I don't even understand what the sentence "reality is incomplete" means.

* If you say that reality is vague then I disagree with you, because experimental outcomes are not vague, but accurate. It is quantum theory that is vague and inaccurate (statistical), but not reality. Let us recall Young's Double-Slit Experiment for a single particle. The impact of the particle on the screen is a pinpoint dot, not a fuzzy blob, isn't it? So, reality is accurate, but not vague.

It is important not to get bogged down in apparent terminological differences. But there are strong reasons for using particular words here.

Indeterminate - simply means not determined. Which is a weak description based on what something is not, rather than what it positively is.

Incomplete - again the same issue. But now we are talking about epistemology rather than ontology. Our knowledge state is either complete or not complete. Reality is either crisply determined or not yet determined.

Vague - this is a new term with its own technical definition. It sort of means what "vague" means in everyday speech. But it also means something more precise here. A state of symmetric potential (in which there is neither local nor global yet existing).

Experimental outcomes are of course not vague. Measurements are crisp. Or any uncertainty gets rounded off to create some crisp figure (and even a probabilistic measurement with stated error bars is crisp!).

So again, saying reality begins in vagueness is not the same as saying it is vague. It is of course defined by its degree of successful crispness.

What is really being done here is that a whole new dimension of reality is being introduced - the dimension along which we might measure development. Real development. The creation of information.

The standard view just takes things to be already in some state, then we have to look closely to find out which state. There is no need to measure development because it is presumed there is no actual development.

But once you accept an observer-created reality, one in which the ends creates its own means, then you have to find some dimension along which this strange physical action is taking place. You need new words suitable to the task. Vague~crisp is the pairing that works for me.

Fuzzy isn't any good as it has already been co-opted for a quite different technical useage.

In my opinion, due to the impossibility of QM to make complete predictions, we are tempted to conclude that nature is fuzzy like QM. But experimental outcomes are the proof that nature is accurate while QM is statistical and incomplete.

Again, reality starts vague and becomes crisp via a developing history of local~global interactions. So reality is both. And fundamentally both, as the generalised observing system is as necessary to the "something that happens" as the localised potentials.

Initial conditions and boundary constraints - the standard furniture of systems.

You are getting hung up on saying everything must be about this, and so nothing can be about that. Yet the science itself tells us always that the whole story (the holistic story) demands its dualities, its complementarities, its dichotomies.

Even in this thread, the rather confused statement "the whole is greater than its parts" was re-hashed. Really, what should be said is that the whole is as fundamental as its parts. Or better yet, that the whole creates its parts just as much as the parts create their whole.

QM demands we let go of something that seemed an inviolable assumption about reality. But few people are willing to do this. Even fewer have worked out what that something actually is.

Again, listen to the prominent modern systems thinkers like Murray Gell-Mann, Ilya Prigogine, Stuart Kauffman.

 

[computerphys]

Again, reality starts vague and becomes crisp via a developing history of local~global interactions. So reality is both

How do we know that "reality starts vague"?

QM demands we let go of something that seemed an inviolable assumption about reality. But few people are willing to do this.

Is determinism that assumption?

How does all this (vagueness and inviolable assumptions) change the fact that QM cannot make accurate predictions while nature can? QM cannot explain nor emulate how nature renders a measurement.

Predictive completeness is not fulfilled by QM. Do you agree with this?

 

[apeiron]

How do we know that "reality starts vague"?

How do we know anything? Assume some axioms and start modelling.

Is determinism that assumption?

Determinism is part of a metaphysical package that includes mechanicalism, atomism, locality and monadism. But broadly, it is the presumption that things definitely/crisply just exist - rather than the alternative fundamental presumption that all is process, everything must develop, etc.

How does all this (vagueness and inviolable assumptions) change the fact that QM cannot make accurate predictions while nature can? QM cannot explain nor emulate how nature renders a measurement.

Predictive completeness is not fulfilled by QM. Do you agree with this?

I think this is where you are in error. Reality is never completely realized in fact.

We can measure some aspect of some event or interaction, but not with infinite accuracy. And increasing accuracy about one aspect, decreases it for complementary ones.

So reality actually remains vague at the margins.

[EDIT] I guess you mean here that a QM model gives you only a probability, then you have to go and find out what actually happened with an act of measurement.

But that is first setting up a model of a constrained situation (yielding some crisp probablistic statements - not vague ones). Then applying further constraints via the act of measurement.

Before the act of measurement, you could have changed your model and decided to measure some other aspect of things. But after the measurement, you have really changed things themselves. Theory says those other unmeasured aspects are entangled with the wider world still. Certainty you appear to have created in one locale is matched by uncertainty created elsewhere.

Anyway, again, it does not appear the case that reality just is what it is in some normal ontological sense. You can push the uncertainty around the system but never get rid of it completely.

 

[computerphys]

I think this is where you are in error. Reality is never completely realized in fact ... So reality actually remains vague at the margins.

Sorry for being so stubborn, but I don't see any logical contradiction between the complementarity of reality (your point) and the lack of predictive completeness of QM (my point). Both can be true at the same time. Where is the error?

I guess you mean here that a QM model gives you only a probability, then you have to go and find out what actually happened with an act of measurement.

I agree with the former (QM is incomplete) but disagree with the latter (QM is in-completable).

 

[apeiron]

Sorry for being so stubborn, but I don't see any logical contradiction between the complementarity of reality (your point) and the lack of predictive completeness of QM (my point). Both can be true at the same time. Where is the error?

Put this way, I am more in agreement. QM does predict probabilities and in this sense is not complete. The question then was who to blame? Is reality actually only ever in some definite state and so a better theory could be complete? Or is reality never fully definite, and so always inherently a little spontaneous even in the most constrained circumstances we can imagine?

I agree with the former (QM is incomplete) but disagree with the latter (QM is in-completable).

And I prefer to think QM reveals something deep about the mistaken assumptions we might be making about reality. So instead of trying to get rid of the uncertainty/nonlocality/indeterminancy, I see it as a description of the initial conditions.

 

[computerphys]

Put this way, I am more in agreement. QM does predict probabilities and in this sense is not complete. The question then was who to blame?

Heisenberg uncertainty principle, I'm afraid. It seems to be a fundamental feature of nature. We are dealing with non-deterministic processes and QM can only address some general patterns of behavior that become deterministic, but never their non-deterministic root. This limitation is due to the very concept of science, unable to deal with things not based on rules:

Morpheus: I've seen an agent punch through a concrete wall. Men have emptied entire clips at them and hit nothing but air. Yet their strength and their speed are still based in a world that is built on rules. Because of that, they will never be as strong or as fast as you can be.

Sorry for the apparently out of context citation, but think twice about it ...

The world that is built on rules is QM. But nature is superior.

Now, next question should be: why is everybody so sure that QM is complete, when, in fact it is not?

 

[GeorgCantor]

Now, next question should be: why is everybody so sure that QM is complete, when, in fact it is not?

Well Einstein might have been right after all that there is an underlying reality(and so qm is incomplete), but after Bell, if realism is to hold, that underlying reality has to involve ftl influences(non-local pilot waves, angels, gods, or some other godly influence; I reject the infinite number of universes on occam's razor grounds). Or perhaps realism is at fault, or both realism and locality altogether. It's really a personal issue and how you want to spend your life thereon. The old mechanistic, clockwork Newtonian universe is dead, so my personal feeling is that both realism and locality will go down the rabbit hole, but take your pick, if so you wish(while the option of choosing is still there).

 

[SW VandeCarr]

Heisenberg uncertainty principle, I'm afraid. It seems to be a fundamental feature of nature. We are dealing with non-deterministic processes and QM can only address some general patterns of behavior that become deterministic, but never their non-deterministic root.

The HUP is a different issue. It involves the measurement of two complementary variables, one of which can in principle be exact. If you know the exact position of a particle, you cannot know it's exact momentum and vise-verse. In fact if you think about it, you can apply the HUP to a bowling ball as well as to any moving particle wrt some reference system. To obtain the momentum, an object must move, making its position uncertain for any measure of momentum at the same time.

 

[computerphys]

The HUP is a different issue. It involves the measurement of two complementary variables, one of which can in principle be exact. If you know the exact position of a particle, you cannot know it's exact momentum and vise-verse. In fact if you think about it, you can apply the HUP to a bowling ball as well as to any moving particle wrt some reference system. To obtain the momentum, an object must move, making its position uncertain for any measure of momentum at the same time.

Your explanation of HUP is perfectly compatible with a fundamental non-deterministic behavior of the system. When you get a certain eigenvalue at a measurement outcome, QM cannot predict it because this process is non-deterministic. So, HUP is not a different issue, unless you find a logical contradiction somewhere between your point and mine.

 

[GeorgCantor]

The HUP is a different issue. It involves the measurement of two complementary variables, one of which can in principle be exact. If you know the exact position of a particle, you cannot know it's exact momentum and vise-verse. In fact if you think about it, you can apply the HUP to a bowling ball as well as to any moving particle wrt some reference system. To obtain the momentum, an object must move, making its position uncertain for any measure of momentum at the same time.

This classical description is invalid. Think about the relationship between the HUP and an electron in a box.

 

[imiyakawa]

why is everybody so sure that QM is complete, when, in fact it is not?

Everyone, you must remember computerphys's pointed definition of a complete theory (which you may disagree with, but he's just outlining a semantic category).

One that predicts experiments of results - probability distributions aren't even good enough for this theory to be complete! So, he's saying QM is in-completable if collapse to discrete state is random (and even acausal) because it doesn't fit this definition.

Based on the category he has assigned to a complete theory, he is correct if there is an acausal random element to nature. Based on other categories that you may prefer, the assertion of in-completeness in principle is incorrect.

No point debating language any more.

 

[computerphys]

No point debating language any more.

Yes, I think all this thread is related to the meaning of the word "complete". Nevertheless I find a problem accepting the mainstream concept the word "complete" has in science. Would you agree with the following case?

A.- Science has a complete explanation of the Jedi's force at Star Wars Universe.
B.- No way! Tell me, what explanation is that?
A.- None.
B.- But you told me that science had a complete explanation ...
A.- That's right. What I have just told you is all that science can say about the Jedi's force. And according to definition #1 this is a "complete theory".
B.- Oh, man, I hate scientists!

Well, it seems B is a bit disappointed about the concept of "complete theory".

In my opinion, definition #1 for a "complete theory" should be seriously considered and reviewed because it may lead to important misunderstandings. I never would say a pool is full(complete) just because I ran out of water to fill it anymore. And you?

 

[imiyakawa]

I don't think we need to discuss language categories any more. "In my opinion, definition #1 for a "complete theory" should be seriously considered and reviewed because it may lead to important misunderstandings." I'm sure physicists aren't lazying about :D There are people chasing determined interpretations and random interpretations. Where else should they be searching?

"it seems B is a bit disappointed"

It's because A. is incorrect. If acausal randomness, in the third line A. should have said "acausality". "None" is a bit misleading.

"B.- Oh, man, I hate scientists!"

B.'s annoyance is well understood, but if reality is acausally random then it's acausally random.

 

[Pythagorean]

Just to interject with some actual QM, HUP isn't the only UP. Google general uncertainty principle and read about when operators commute and eigenvector redundancies. There's no reason to focus on HUP in particular. It might even be more apropriate to review the math involved. The first google result has a discussion on it, with math.

(which in QM, the observables like position and speed are operators, not variables. The wave function is the variable)

 

[computerphys]

B.'s annoyance is well understood, but if reality is acausally random then it's acausally random.

Probably, if A hadn't told B that science had a "complete theory" for Jedi's force, B would feel much better.

The problem is not that QM is unable to explain certain experience. The problem is science claiming it to be complete, letting people misunderstand the current fundamental limitations science has found and cannot avoid.

That "acausally random" behavior of nature, should we call it "magic"? Being random, its explanation becomes unreachable by science, isn't it? What about telling people that the noise they can observe in a digital picture is "magic"?

Are all these questions irrelevant and just about "language categories"?

do you feel honest when saying QM is complete?

 

[robheus]

No scientific theory is ever complete.

 

[computerphys]

No scientific theory is ever complete.

If that is so obvious, what is the point of discussing the completeness of Quantum Theory? Why did Einstein insist at this point? Why did Bohr utter much the contrary? How many physicists do you think are there that accept the incompleteness of Quantum Theory? Very few, I'm afraid.

 

[Fuzzystuff]

If that is so obvious, what is the point of discussing the completeness of Quantum Theory? Why did Einstein insist at this point? Why did Bohr utter much the contrary? How many physicists do you think are there that accept the incompleteness of Quantum Theory? Very few, I'm afraid.

I accept that it is incomplete. I don't think science could provide a complete theory. That is my personal belief.

 

[harroxelas]

I think of it tis way:

If we think it's complete and it's in fact complete, no harm done.

If we think it's complete and it's in fact incomplete, we loose!

If we think it's incomplete and it's in fact complete, we'll just look for something that isn't there. No harm done, except that people could be working on some other field.

If we think it's incomplete and it's in fact incomplete, let the joy of discovery continue!

So I think it's best to think it's incomplete!