Does consciousness cause Wave-Function collapse?

[atyy]

Its the nature of ideas. There are many silly positions that can't be disproved. They are still silly - but in science that is not the standard - correspondence with experiment is.

I don't think the consciousness causing collapse is that silly, especially if one considers the Bayesian view of probability. In Bayesian probability, probability is subjective, and Bayes's rule updates a state of knowledge. If the state is not necessarily real, but just a tool to update a Bayesian probability, then it is updating a state of knowledge. Now of course, consciousness is not defined, but it is fun shorthand for something that has a state of knowledge and that can do Bayesian updating.

 

[craigi]

I don't think the consciousness causing collapse is that silly, especially if one considers the Bayesian view of probability. In Bayesian probability, probability is subjective, and Bayes's rule updates a state of knowledge. If the state is not necessarily real, but just a tool to update a Bayesian probability, then it is updating a state of knowledge. Now of course, consciousness is not defined, but it is fun shorthand for something that has a state of knowledge and that can do Bayesian updating.

It is a valid interpretation. The real problem with consciousness causing collapse, is that it's not easy to do science with a subjective-realist world view. You can circumvent the problem, by adding axioms to define domains where all observers agree.

A lot depends upon what the intent for your interpretation is. I don't see any use for consciousness causing collapse interpretations, other than that they're fun for boggling the mind and that they prevent us from becoming too dogmatic.

If I were to make a bet, I'd say that the the MWI will be proven in the next century by quantum computing and/or AI, followed by the findings being retro-fitted into other interpretations.

 

[atyy]

I just hate pseudoscience, and I hate everything about "the secret" or "what the bleep" "mind creating reality", so I just want to remove all my doubts about it, and to be sure that reality is fixed and objective.

It is a valid interpretation. Regardless of where one's dogma lies, the real problem with consciousness causing collapse, is that it's not easy to do science with a subjective-realist world view.

Why not? The standard interpretation is Copenhagen, with a subjective classical/quantum cut. The cut can be shifted, depending on which part of the universe one is interested in. So quantum experimenters doing local experiments in Texas and in Singapore will put their respective cuts in different places. Copenhagen does acknowledge objective reality. But it also acknowledges that it is an incomplete theory of the reality, and is only interested in predicting measurement outcomes. So there is no need for subjective cuts to conflict with objective reality.

 

[atyy]

It is a valid interpretation. The real problem with consciousness causing collapse, is that it's not easy to do science with a subjective-realist world view. You can circumvent the problem, by adding axioms to define domains where all observers agree.

Can one do that? It is often said that decoherence plus some additional axioms will do that. For example the probability sieve is proposed as one method of choosing the preferred basis, whereas in the Copenhagen interpretation the basis is chosen by the observer. However, I don't think an additional axiom can place the cut, because the cut is not unique. If Alice and Bob do local experiments and are only interested in local outcomes, they can place the cut in different places.

A similar point is made by Schlosshauer on p15 of http://arxiv.org/abs/quant-ph/0312059
"Finally, a fundamental conceptual difficulty of the decoherence-based approach to the preferred-basis problem is the lack of a general criterion for what defines the systems and the “unobserved” degrees of freedom of the environment (see the discussion in Sec. III.A). While in many laboratory-type situations, the division into system and environment might seem straightforward, it is not clear a priori how quasiclassical observables can be defined through environment-induced superselection on a larger and more general scale, when larger parts of the universe are considered where the split into subsystems is not suggested by some specific system-apparatus surroundings setup."

 

[bhobba]

Not at all. In this conext I'm referring to an observation made by a conscious observer

But QM is independent of that. We are going around in circles - I keep saying the theory is expressed in terms of things that are observer independent and you keep saying it is. I will leave it there - its got nothing to do with an observer.

Thanks
Bill

 

[atyy]

I have a letter accepted for publication in Physics Today pointing out that Zurek's argument, commonly referred to as 'Quantum Darwinism', is circular. MWI based only on 'decoherence' does not gain a classical splitting basis unless it is put in by hand at the beginning. (See http://arxiv.org/abs/1412.7950 and http://arxiv.org/abs/1406.4126 )
Thus the classical world of experience is not successfully explained in MWI. Publication of my letter, as well as another reply from someone else to Zurek's article, is currently being held up pending a reply from Zurek. At this time, I do not know when (or if) that will happen, since he has not replied to any of his critics in the literature (that I know of) to date.
Also, it's certainly not necessary to appeal to 'consciousness' for wave function collapse. (I discuss this in my new book, as well as in my 2012 CUP book.)

I think this is an open problem. Schlosshauer makes comments in his review http://arxiv.org/abs/quant-ph/0312059 that broadly agrees with you. He also says that Zurek acknowledged it as a problem in 1998. I don't know whether Zurek has made progress on this issue since then. Bolding below is mine.

p8: "Also, there exists no general criterion for how the total Hilbert space is to be divided into subsystems, while at the same time much of what is called a property of the system will depend on its correlation with other systems. This problem becomes particularly acute if one would like decoherence not only to motivate explanations for the subjective perception of classicality (as in Zurek’s “existential interpretation,” see Zurek, 1993, 1998, 2003b, and Sec. IV.C below), but moreover to allow for the definition of quasiclassical “macrofacts.” Zurek (1998, p. 1820) admits this severe conceptual difficulty: In particular, one issue which has been often taken for granted is looming big, as a foundation of the whole decoherence program. It is the question of what are the “systems” which play such a crucial role in all the discussions of the emergent classicality. (. . . ) [A] compelling explanation of what are the systems—how to define them given, say, the overall Hamiltonian in some suitably large Hilbert space—would be undoubtedly most useful."

p15: "Finally, a fundamental conceptual difficulty of the decoherence-based approach to the preferred-basis problem is the lack of a general criterion for what defines the systems and the “unobserved” degrees of freedom of the environment (see the discussion in Sec. III.A). While in many laboratory-type situations, the division into system and environment might seem straightforward, it is not clear a priori how quasiclassical observables can be defined through environment-induced superselection on a larger and more general scale, when larger parts of the universe are considered where the split into subsystems is not suggested by some specific system-apparatus surroundings setup."

 

[craigi]

But QM is independent of that. We are going around in circles - I keep saying the theory is expressed in terms of things that are observer independent and you keep saying it is. I will leave it there - its got nothing to do with an observer.

Thanks
Bill

Bill,

I'm not telling you that the MWI is expressed in terms of observer dependence. I'm saying that it results in an observation selection effect. In my first post in the thread, I mentioned quantum suicide, which I think you missed. I think if you review the thought experiment, then we'll understand each other perfectly well.

http://en.wikipedia.org/wiki/Quantum_suicide_and_immortality
http://wiki.lesswrong.com/wiki/Observation_selection_effect

Nevertheless, I've no interest in dragging out this misunderstanding either.

 

[bhobba]

I'm saying that it results in an observation selection effect.

I am saying because the interpretation doest even require conscious observers to exist its not possible for it to have such.

The quantum suicide effect is, to be blunt, simply philosophical dialectical sophistry of zero observational consequence:
http://en.wikipedia.org/wiki/Quantum_suicide_and_immortality
' it is not possible for the experimenter to experience having been killed, thus the only possible experience is one of having survived every iteration'

The worlds are all separate. You may just as easily conclude it is not possible for the experimenter to experience not having being killed as being alive. Indeed via that reasoning its not possible to experience anything. But since they are separate what goes on in other worlds has zero effect on what goes on in your world.

But then again you are talking about worlds with conscious observers - the interpretation doesn't require that.

Thanks
Bill

 

[craigi]

I am saying because the interpretation doest even require conscious observers to exist its not possible for it to have such.

The quantum suicide effect is, to be blunt, simply philosophical dialectical sophistry of zero observational consequence:
http://en.wikipedia.org/wiki/Quantum_suicide_and_immortality
' it is not possible for the experimenter to experience having been killed, thus the only possible experience is one of having survived every iteration'

The worlds are all separate. You may just as easily conclude it is not possible for the experimenter to experience not having being killed as being alive. Indeed via that reasoning its not possible to experience anything. But since they are separate what goes on in other worlds has zero effect on what goes on in your world.

But then again you are talking about worlds with conscious observers - the interpretation doesn't require that.

Thanks
Bill

It seems that you dislike the multiverse and anthropic principle that come along with the MWI. They're widely accepted features of the theory. At least we're on the same page now.

 

[bhobba]

It seems that you dislike the multiverse and anthropic principle that come along with the MWI.

The anthropic principle is not part of MW. I have zero Idea where you got that from. The multiverse is also different to MW.

The anthropic principle is the idea the many fundamental constants we see is explained because we happen to exist and they have to be that for that to occur. There are many alternate universes that are different. The problem here is that in MW each world has exactly the same fundamental laws and constants. The multiverse requires something like eternal inflation.

Have you actually studied MW from a book like the following:
http://users.ox.ac.uk/~mert0130/books-emergent.shtml

Thanks
Bill

 

[bhobba]

It is a valid interpretation. The real problem with consciousness causing collapse, is that it's not easy to do science with a subjective-realist world view. You can circumvent the problem, by adding axioms to define domains where all observers agree..

The real problem is, just like solipsism, is it leads to a world view most find far too weird to accept.

Thanks
Bill

 

[craigi]

The real problem is, just like solipsism, is it leads to a world view most find far too weird to accept.

Thanks
Bill

Sure. That's certainly a good objection, if you're choosing your interpretation based up aesthetics.

 

[craigi]

The anthropic principle is not part of MW. I have zero Idea where you got that from.

The anthropic principle is the idea the many fundamental constants we see is explained because we happen to exist and they have to be that for that to occur. There are many alternate universes that are different. The problem here is that in MW each world has exactly the same fundamental laws and constants. The multiverse requires something like eternal inflation.

Wat you're talking about is the fine tuning problem, which is relevant to the anthropic principle, but it isn't what the anthropic princple is.

Simply put, the anthropic principle is the requirement that a conscious observer must be present for an observation of the physical universe to be made.

In this context, the term observation, is used in the traditional sense and is not a quantum mechanical observation.

The multiverse is also different to MW.

Tegmark classifies the MWI universe as a level 3, multiverse.

Greene classifies the MWI universe as one of the nine types of multiverse.

 

[kith]

Now if you want to attack MW I think the quantum eraser experiment may prove difficult to handle - what happens to those worlds when decoherence is unscrambled?

I think that that if the splitting of worlds occurs whenever we have approximate decoherence, then it has to be possible for the worlds to remerge. Else, dynamics with periodic decoherence and recoherence don't fit in.

 

[rootone]

The real problem is, just like solipsism, is it leads to a world view most find far too weird to accept.
Bill

I think the comparison to solipsism is a good one.
It is an example of an assertion that may or may not be true, and which has zero possibility of either being proved or falsified.
Either way, it makes no difference in terms of explaining the observations which have actually been made,
The results of anyone given experiment are what they are, regardless of consciousness being present.
Just because a similar experiment could be done and the result could differ is to down to probability.
For me anyway, the notion that different results arising has a causal connection to whoever is doing the experiment sounds not only too weird to accept, it sounds plain daft.

 

[kith]

What bothers me more is the fact that Isn't obvious that "consciousness' has nothing to do with the collapse, but the system doing the measurement , why do people insists in this matter?

I think the whole thing is mostly a problem of terminology.

In my opinion, the terms "measurement" and "observer" should be reserved for science, i.e. we should use them only if someone actually performs an experiment on a system of his choice. If we do this, it is clear that consciousness has something to do with measurements but there's nothing mysterious: there's just a person doing science.

I would say that "collapse" refers to the perception of this person, while decoherence is an objective physical fact which looks the same for all external observers. I also think that "collapse" is a bad name because it sounds so objective.

 

[craigi]

I think that that if the splitting of worlds occurs whenever we have approximate decoherence, then it has to be possible for the worlds to remerge. Else, dynamics with periodic decoherence and recoherence don't fit in.

The definition of splitting is more deliberate than that. Worlds split during thermodynamically irreversible processes, which induce decoherence.

As we know from thermodynamics, irreversibility is a statisical property of a process in forward time, so theoretically, worlds could merge, in the same way that smashed glass could "magically" fix itself, but we feel comfortable saying that it's "never" going to happen.

 

[kith]

The definition of splitting is more deliberate than that. Worlds split during thermodynamically irreversible processes, which induce decoherence.

There are no exactly irreversible processes. If you model the dynamics of open quantum systems it doesn't matter whether something is truly irreversible or just has an astronomically large recurrence time but for the MWI this isn't enough. At least not unless you don'introduce something which says how long the recurrence time needs to be in order for a splitting to happen.

 

[rkastner]

Its ambivalent to such an issue. It simply accepts it. Ballentine doesn't even believe decoherence has anything to say about interpretational issues. And you know what - within his interpretation he is correct. For example if you read his 1970 paper its really an interpretation like BM in disguise. He has modified it a bit in his textbook so that is no longer true - but still he simply considers issues others worry about as non issues.

I know philosophy types sometimes say don't bother with Ballentine - its not even an interpretation since its basically just the formalism. Its a view I disagree with - but really we are getting way off topic.

Thanks
Bill

Thanks--I agree that he dismisses certain interpretational issues as non-issues. That's very convenient. But it puts him in a rather untenable position, since he introduced his interpretation ostensibly to solve interpretational issues. Apparently the ones his approach cannot solve, he declares them not in need of being solved--saying 'don't worry about it'. That's just a way of saying: I have given up on solving that and so should you." But another intepretations ( PTI) can solve them. So I would think that would count in their favor.

 

[craigi]

There are no exactly irreversible processes. If you model the dynamics of open quantum systems it doesn't matter whether something is truly irreversible or just has an astronomically large recurrence time but for the MWI this isn't enough. At least not unless you don't introduce something which says how long the recurrence time needs to be in order for a splitting to happen.

True.

Worlds merge almost never in the MWI, in the same way that a smashed object almost never "magically" reforms.

There isn't an exact definition for when splitting has taken place in the same way that there isn't an exact definition for an irreversible process.

 

[rkastner]

That's easy to understand from the minimal statistical interpretation. A baseball is well described as a classical system, because you are only interested in very coarse-grained observables and not on the microscopic details. You don't follow the quantum state of $\mathcal{O}(10^{24})$ molecules in detail, because this is not possible in practice and fortunately far from being necessary to understand the "relevant" "classical" degrees of freedom (the center of mass/momentum motion and the rotation if you are satisfied with the "rigid-body approximation"). For those very rough effective degrees of freedom it is enough to consider the expectectation values which follow with high accuracy the classical description in terms of Newtonian mechanics.

Thanks. But does it account for the separation of degrees of freedom of the universe into recognizable objects such as baseballs, with recognizable centers-of-mass? Or does it take distinguishable (i.e. non quantum-correlated) objects as primitive?

 

[Rajkovic]

I don't even know why Craig is saying woo woo here. There is no need of conscious observers in quantum mechanics. Or are you trying to prove that God exist and is observing the Universe? lol

 

[craigi]

I don't even know why Craig is saying woo woo here. There is no need of conscious observers in quantum mechanics. And perception is not reality.

I'm not. I don't believe that there any any mystical properties to quantum mechanics. I see little merit in the consciousness causes collpase interpretations. If you read my posts again, that should be clear.

The problem that I see here, is that if you become dogmatic about your world view, just the word 'consciousness' can panic you, even if it used in a way that is completely correct and well accepted.

Remember that as scientists, we oppose dogma, that does not mean that we replace one dogma with another of own.

There is no need of conscious observers in quantum mechanics

It is correct, that we can interpret QM without consciousness, but it's also true that we can interpret QM in way where consciousness plays an integral role.

We should be clear about our goal when choosing an interpretation. If we're just worried that we'll arrive at a conclusion that upsets us, then the problem has nothing to do with physics anymore.

 

[carllooper]

We can interpret "consciousness" as another word for an observation, in the sense that I might say, when I observe an apple on the table, that I'm conscious of that apple on the table. And in this way we can neutralise any metaphysical connotations associated with the term "consciousness". Indeed we can speak of machine consciousness as another way to contain the term.

We're then back on more firmer ground and asking whether whatever-we-call-it plays a role in wave function collapse. And of course, whether there is such a thing as wave function collapse.

By convention, an observation (or consciousness) is an effect, rather than a cause. I see a shimmer on the horizon as an effect of refraction of light in hot air, or as a function of an oasis in which the light is reflecting off ripples in the water, neither of which is a function of me in particular seeing it (by convention), but as a function of it (oasis or hot air) being there regardless.

So it's very difficult to reverse this and say that my observation plays some sort of necessary role in what is there (be it oasis or hot air).

Convention dictates that we phrase it the other way.

To speak of an observer determining wave function collapse is similar to the suggestion that a voter determines the outcome of an election. Or rather: that one could determine the outcome of an election from an individual vote.

Voters play a role. They participate in the election. But it's not their particular vote, on it's own, that determines the outcome of the election. It is their vote and everyone else's vote that determines the outcome (and determines that their vote can not do anything else but conform to the probability of their vote, given the election results). But more importantly, the outcome of an election is a representation of a more important reality: the will of the people, rather than the will of any particular person, or despot.

In a sense, it is this reality (the will of the people), which determines everyone's individual vote. The election (and one's own particular participation in it) is just a way of making that reality visible. By convention we assume that the reality is there whether an election is held or not. There's nothing to be lost by such an assumption. It works.

But we also run into trouble if we try to determine a mechanism for this - how an individual vote can be a function of the election (or rather: a function of what an election represents). We speak of wave function collapse in the sense that the election result is not to be found in any individual vote. The election result "collapses" (so to speak) when we try to isolate it any individual vote. This collapse is not a mechanism as such - but a way of speaking.

C

 

[atyy]

We can interpret "consciousness" as another word for an observation, in the sense that I might say, when I observe an apple on the table, that I'm conscious of that apple on the table. And in this way we can neutralise any metaphysical connotations associated with the term "consciousness". Indeed we can speak of machine consciousness as another way to contain the term.

We're then back on more firmer ground and asking whether whatever-we-call-it plays a role in wave function collapse. And of course, whether there is such a thing as wave function collapse.

By convention, an observation (or consciousness) is an effect, rather than a cause. I see a shimmer on the horizon as an effect of refraction of light in hot air, or as a function of an oasis in which the light is reflecting off ripples in the water, neither of which is a function of me in particular seeing it (by convention), but as a function of it (oasis or hot air) being there regardless.

But if the measurement outcome is not observed, then the wave function does not necessarily collapse (although there is nothing wrong with collapsing it then, but one could just use decoherence without collapse).

 

[bhobba]

Simply put, the anthropic principle is the requirement that a conscious observer must be present for an observation of the physical universe to be made.

First I have heard of that one. But if that's it then its simply a load of un-testable philosophical waffle - but I don't think its what is meant by it. Since conscious observers exist in our universe there is no way to test if observations can't be made in a universe where they don't exist. But none of our physical theories demand that - QM, string theory, classical mechanics - none.

My understanding of it is the following definition I dug up - its 'the philosophical consideration that observations of the physical Universe must be compatible with the conscious and sapient life that observes it.'

It says nothing about a conscious observer being present for an observation to be made.

Thanks
Bill

 

[bhobba]

I think the whole thing is mostly a problem of terminology.

Indeed.

Many threads have alluded to the confusion the word observation in QM engenders. It historical so its very hard to get rid of.

In QM loosely speaking it means when some kind of mark is left here in the macro world - but that is loose. Technically it when decoherence has occurred.

Thanks
Bill

 

[craigi]

We can interpret "consciousness" as another word for an observation, in the sense that I might say, when I observe an apple on the table, that I'm conscious of that apple on the table. And in this way we can neutralise any metaphysical connotations associated with the term "consciousness". Indeed we can speak of machine consciousness as another way to contain the term.

We're then back on more firmer ground and asking whether whatever-we-call-it plays a role in wave function collapse. And of course, whether there is such a thing as wave function collapse.

By convention, an observation (or consciousness) is an effect, rather than a cause. I see a shimmer on the horizon as an effect of refraction of light in hot air, or as a function of an oasis in which the light is reflecting off ripples in the water, neither of which is a function of me in particular seeing it (by convention), but as a function of it (oasis or hot air) being there regardless.

So it's very difficult to reverse this and say that my observation plays some sort of necessary role in what is there (be it oasis or hot air).

Convention dictates that we phrase it the other way.

To speak of an observer determining wave function collapse is similar to the suggestion that a voter determines the outcome of an election. Or rather: that one could determine the outcome of an election from an individual vote.

Voters play a role. They participate in the election. But it's not their particular vote, on it's own, that determines the outcome of the election. It is their vote and everyone else's vote that determines the outcome (and determines that their vote can not do anything else but conform to the probability of their vote, given the election results). But more importantly, the outcome of an election is a representation of a more important reality: the will of the people, rather than the will of any particular person, or despot.

In a sense, it is this reality (the will of the people), which determines everyone's individual vote. The election (and one's own particular participation in it) is just a way of making that reality visible. By convention we assume that the reality is there whether an election is held or not. There's nothing to be lost by such an assumption. It works.

But we also run into trouble if we try to determine a mechanism for this - how an individual vote can be a function of the election (or rather: a function of what an election represents). We speak of wave function collapse in the sense that the election result is not to be found in any individual vote. The election result "collapses" (so to speak) when we try to isolate it any individual vote. This collapse is not a mechanism as such - but a way of speaking.

C

Tegmark approaches a formal definition of an observer here.

http://arxiv.org/abs/1401.1219

I think everyone in this thread should read it. He acknowledges the traditional resistance to considering consciousness amongst physicists and discusses why this important in physics and specifically quantum mechanics. It might not change your world view, but it will at least, demonstrate the challenges to an entrenched position.

Abstract:
We examine the hypothesis that consciousness can be understood as a state of matter, "perceptronium", with distinctive information processing abilities. We explore five basic principles that may distinguish conscious matter from other physical systems such as solids, liquids and gases: the information, integration, independence, dynamics and utility principles. If such principles can identify conscious entities, then they can help solve the quantum factorization problem: why do conscious observers like us perceive the particular Hilbert space factorization corresponding to classical space (rather than Fourier space, say), and more generally, why do we perceive the world around us as a dynamic hierarchy of objects that are strongly integrated and relatively independent? Tensor factorization of matrices is found to play a central role, and our technical results include a theorem about Hamiltonian separability (defined using Hilbert-Schmidt superoperators) being maximized in the energy eigenbasis. Our approach generalizes Giulio Tononi's integrated information framework for neural-network-based consciousness to arbitrary quantum systems, and we find interesting links to error-correcting codes, condensed matter criticality, and the Quantum Darwinism program, as well as an interesting connection between the emergence of consciousness and the emergence of time.

 

[julcab12]

MWI

Great question. I address this in specific terms in my new book. The interaction that leads to collapse is one in which there is a response from an absorber. There are other interactions (virtual particle exchanges) that do not lead to collapse. Nowhere in this account does one need to talk about an 'observer,' although observers can participate in collapsing interactions by being composed of absorbers themselves. It's just that collapse is not limited to an 'observer'.

Virtual particles are not observables -- construction on the internal part of the feyman diagram so i don't know if it is considered an interaction. But it make sense that observer can have a misleading role in the collapse. Any act on the system whether natural, physical or conscious(whatever that means) can have an effect. It just happen we're here to observed it in our own perspective. Or am i missing something?

 

[Dale]

And with that we will consider this horse well and truly dead and stop beating it.