Can a computer be an observer?

[Dmitry67]

Cool! So we agreed! I 100% agree with your formulation.

But now let me ask the most important question:
as based on (2) parallel worlds are real as well,

are observers there (in these parallel worlds) conscious?
do they feel pain?

 

[Demystifier]

Cool! So we agreed! I 100% agree with your formulation.

But now let me ask the most important question:
as based on (2) parallel worlds are real as well,

are observers there (in these parallel worlds) conscious?
do they feel pain?

Since I have no idea how consciousness arises, I will answer you through an analogous question:
Are tree branches without ants conscious?
Do they feel pain?

By the way, IMHO the problem of consciousness is the most difficult problem in science. Compared to it, the problem of interpretation of QM is trivial.

 

[Dmitry67]

Yes, this problem of consciousness is very difficult. Note that my question led you to a trap.

If you answer: Yes, they are conscious, then I say: then what is a difference between BM and MWI? All other beings in the alternative branches feel, think, they are conscious… Their world is exactly the same as ours. Then there is absolutely no advantage in BM, as all branches are equal.

If you answer: No, they are not conscious, then I say: so you claim that consciousness is actually *created* by the BM particles, because the same human – receiving signals, replying something, with fully functional brain (wavefunction of fully functional brain) is not conscious just because waves are empty! And as particles are undetectable in principle and do not affect the wavefunction, then it looks as pure magic.

By answering ‘I don’t know’ you don’t avoid the problem – we just don’t know what problem to address.

 

[Demystifier]

Yes, this problem of consciousness is very difficult. Note that my question led you to a trap.

If you answer: Yes, they are conscious, then I say: then what is a difference between BM and MWI? All other beings in the alternative branches feel, think, they are conscious… Their world is exactly the same as ours. Then there is absolutely no advantage in BM, as all branches are equal.

If you answer: No, they are not conscious, then I say: so you claim that consciousness is actually *created* by the BM particles, because the same human – receiving signals, replying something, with fully functional brain (wavefunction of fully functional brain) is not conscious just because waves are empty! And as particles are undetectable in principle and do not affect the wavefunction, then it looks as pure magic.

By answering ‘I don’t know’ you don’t avoid the problem – we just don’t know what problem to address.

All that I can also say to you for the tree and the ant. So your trap caught you as well.

But more seriously, you made two mistakes above.

First, if I answer Yes, they are conscious, it is not true that there is absolutely no advantage in BM. As I stressed many times (and you ignored the same number of times), the advantage of BM is that it can explain the Born rule.

Second, if I answer No, they are not conscious, it is not true that particles are undetectable in principle. Roughly, this is like saying that consciousness is not detectable in principle. Just the opposite, if anything is detectable, then it is consciousness. Yet, nothing is more difficult to detect by scientific means than consciousness. This is indeed a paradox of consciousness which I don't know how to solve. But whatever the solution is (maybe you know?), the problem with detection of Bohmian particles is of a similar kind.

But since consciousness is so problematic, vague and paradoxical concept, it is better not to use consciousness in physics discussions. If arguments based on consciousness are your only arguments for or against some physical hypothesis, then you arguments are very shaky.

 

[Dmitry67]

Ok, let's begin from the flavor of BM where observers in ‘empty’ branches are conscious (conscious-BM, or c-BM. Another flavor is nc-BM :) )

But more seriously, you made two mistakes above.
First, if I answer Yes, they are conscious, it is not true that there is absolutely no advantage in BM. As I stressed many times (and you ignored the same number of times), the advantage of BM is that it can explain the Born rule.

Yes and no.
Yes, BM explains the Born rule in branching events, but only in the branching events between one ‘real’ branch and others ‘empty’ branches. If the original (source) branch is already empty, then the whole sub-tree is empty and is equivalent to MWI.
Also, as observers in empty branches are conscious in c-BM, then the question I asked before is applicable: how do you know that YOU are ‘real’ observer, not an ‘empty’ one? In either case you are conscious. What if the real branch had gone away 5 billion years ago, when Earth had formed in a different place, and our whole history – is an ‘empty’ sub-tree from the very beginning?

 

[Demystifier]

Also, as observers in empty branches are conscious in c-BM, then the question I asked before is applicable: how do you know that YOU are "real" observer, not an "empty" one?

There is an experimental way to answer this question.
I repeat the same kind of measurement many times. If the statistics of my measurement outcomes obeys the Born rule, then I am the "real" observer. If the statistics obeys the rule that each branch (originating from the same parrent branch) is equally probable, then I am (mostly) the "empty" one. If the statistics obeys some intermediate rule, then I am sometimes "real" observer and sometimes the "empty" one.

Needless to say, such measurements have been performed many times. We all know the results.

 

[Dmitry67]

So if you repeat the same experiment many times, you create billions sub-branches every time. In c-BM, in all these branches YOU are conscious too. So in minutes you end with 100000000000000000 you’s, and only one is non-empty. So why your consciousness systematically falls into the non-empty branch? If you pick randomly any consciousness from universe wavefunction, you have almost no chance to pick up ‘real’ branch!

Isnt it an argument against c-BM?

 

[lugita15]

I don't know of a single big-name physicist (or perhaps even reputable physicist) today who believes in quantum-consciousness ideas. (Roger Penrose is a gifted mathematician, but he is not a physicist)

Based on reading Emperor's New Mind, I think Penrose believes in objective collapse. He thinks that gravity collapses the wave function, but he doesn't think that the state the wave collapses into is random or probabilistic. He believes that there is a deeper, fully deterministic theory underlying quantum theory. He thinks that collapse consists of an object "acquiring information" from some Platonic mathematical heaven. (Yes, it sounds absurd at first glance, but he defends it at length.)

 

[Count Iblis]

Uhm, Penrose certrainly is a physicist (by definition, a physicist is someone who does research in one or more physics topics), one of the most brilliant theoretical physicists. That doesn't mean he is right on this issue, of course.

If you look back at how new theories of physics were developped, what choices one has had to made when formulating the theories, what the motivations for the choices were, you see the following pattern:

Making the most reasonable choice in resolving very academic, often ridiculous sounding thought experiments is far more important than trying to make ad hoc fixes to existing theories (that already work extremely well in practice). The latter approach is often preferred by experimentalists and people who use the theory in practice (the "phenomenologists"). This leads to an inertia against progress.

 

[cesiumfrog]

If you look back at how new theories of physics were developped, what choices one has had to made when formulating the theories, what the motivations for the choices were, you see the following pattern: Making the most reasonable choice in resolving very academic, often ridiculous sounding thought experiments is far more important than trying to make ad hoc fixes to existing theories (that already work extremely well in practice). The latter approach is often preferred by experimentalists and people who use the theory in practice (the "phenomenologists"). This leads to an inertia against progress.

Against progress? No. I think progress in physics comes from those experimentalists you deride, or specifically from opening avenues of novel experimental data. Accumulating a wide variety of speculative and untested (let alone testable) theories isn't quite progress. If Einstein's relativity (I assume that's the historical example you have in mind?) hadn't had a Newtonian limit, or if we lacked the technological refinement to verify it, how would we distinguish it from somebody else's total crackpottery?

 

[Count Iblis]

Against progress? No. I think progress in physics comes from those experimentalists you deride, or specifically from opening avenues of novel experimental data. Accumulating a wide variety of speculative and untested (let alone testable) theories isn't quite progress. If Einstein's relativity (I assume that's the historical example you have in mind?) hadn't had a Newtonian limit, or if we lacked the technological refinement to verify it, how would we distinguish it from somebody else's total crackpottery?

Yes, you have the experimental results on which the previous theories are based on. But what then often happens is that experiments or observations alone don't get you much further. There then can exist theoretical arguments that show that something isn't quite right, even though in practice everything works just fine.

The crucial convicing arguments that lead to new theories are often not based on anything that can even remotely be measured. Of course, if there are a lot of speculative ideas floating around, then that would not amount to real progress. But that happens precisely because people are often too focussed on sticking too closely to what can be experimentally realized.


E.g. in quantum mechanics a lot is made about creating fatter and fatter Schrödinger cat states and trying to close yet another loophole in some Bell's inequality violation test. My opinion is that such exercises are a complete waste of time when it comes to understanding the fundamental nature of quantum mechanics.

Instead we can learn far more by thinking deeply about thought experiments like e.g. the one proposed by David Deutsch in which measurements are undone in a reversible way.

The title of this thread is if a computer can be a observer, and I think that thre only reasonable answer is "yes", because I can consider my brain to be a machine. But then the next questions should be about implementing the observer using a quantum computer that includes all the degrees of freedom that one can think are necessary.

So, if someone thinks that decoherence is necessay, that cannot be used to shoot down such a thought experiment. You can always make that quantum computer large enough, if needed you can consider a quantum computer that simulates our entire galaxy.

So, unless one believes in a real fundamental collapse of the wave function, one should not be able to get away from facing the consequences of such thought experiments. If decoherence is important, we can accommodate for that inside the Hilbert space spanned by the qubits, while the quantum computer itself does not decohere, as we can always imagine placing it in a perfect vacuum at exactly zero temperature.

 

[Dmitry67]

E.g. in quantum mechanics a lot is made about creating fatter and fatter Schrödinger cat states and trying to close yet another loophole in some Bell's inequality violation test. My opinion is that such exercises are a complete waste of time when it comes to understanding the fundamental nature of quantum mechanics.

Yes!
C60 experiments are very cool but the result is absolutely expected.

And I am puzzled about the amount of buzz (on this forum) about non-locality. I understand, there are few diehard localists, but they will never accept nonlocality, no matter what (in the worst case they will hide into superdeterminism), so yes, it is waste of time.

 

[Fra]

This leads to an inertia against progress.

I like the very way you phrased this.

Not only do I think you have a good point (however this doesn't contradict that experimentalists ALSO help moving the frontiers by designing new experiments; to me it's clear what count iblis means).

I also think the same kind of logic is in fact responsible for actualy inertia and gravity in physics. The information state of massive observer, has an inertia against contradicting new information that is somehow constrained by the complexity. So therefore, even not starting with "gravity" explicitly, and just starting with an abstraction containing information processing and information encoding and compression, a concept of inertia as in "resistance to change or revision" enters naturally in such an intrinsic inference model. This is a connection, similar to penrose gravity/collapse idea, but it's has a inverted starting point. I think we don't need to start with gravity, gravity and inertia emerge naturally in this way. All we need is to find the connection of the new generalized concepts and the classical measures of inertia and gravity.

/Fredrik

 

[Fra]

Against progress? No. I think progress in physics comes from those experimentalists you deride, or specifically from opening avenues of novel experimental data. Accumulating a wide variety of speculative and untested (let alone testable) theories isn't quite progress. If Einstein's relativity (I assume that's the historical example you have in mind?) hadn't had a Newtonian limit, or if we lacked the technological refinement to verify it, how would we distinguish it from somebody else's total crackpottery?

I see your concern but there is no conflict between diversity/variation and stability. In an evolutionary model variation is needed for progress, but stability also requires that the variation is controlled and constrained. This is exactly what we have. So there is no conflict. Variation and diversity doesn't threaten the effective consensus, it just rightfully continously questions it, in order to IMPROVE it.

The problem is this:

When you have and existing model/theory or belief, this constrains which questions you ask/which new experiments you design, AND it also determines the way feedback from such experiments is to be INTERPRETED. In particular do we reach a decision problem where we need to update our prior belief in the light of the new evidence. To do this rationally the prior is used as a weight, to also down-weight a priori unlikely feedback, so that in order to change our prior in an a priori unexpected direction, we need to see repeatedly the new feedback. This contains a built-in inertia.

This model, means that your prior beielf (which it a metaphor for our current framework and models) not only determines the way new questions are phrased, it also have a larger rejection level for feedback that is a priori unlikely. This is a form of inertia.

But this is fully rational. It is no critique against experimentalists or anyone else. However it's an excellent observation since it acknowledges how these process does in fact work.

This also means that the beleifs (against a metephor from framework/theoty) automatically evolve, and theories that just doesn't match reality, eventually die out, or are forced to revise. So there is no need to "ban" crazy ideas, crazy ideas kill themselves, and there is also no risk at them come to dominate since they simply aren't viable.

So encouraging variation, does not threaten stability or science IMO. Provocation OTOH rather strengten our positions, and sometimes it happens that some provocation leads to a more viable belief, then this will be preseved. So has it been in the past as well.

/Fredrik

 

[Demystifier]

In c-BM, in all these branches YOU are conscious too.

That's not quite correct. I am not conscious in all these branches. I am conscious in only one of them, simply because I exist in only one of them. In other branches it is someone else who is conscious, even though in some of them this other guy is very similar to me. Although, this distinction is not really essential.

Why your consciousness systematically falls into the non-empty branch? If you pick randomly any consciousness from universe wavefunction, you have almost no chance to pick up ‘real’ branch!

Isnt it an argument against c-BM?

I must admit, it is an argument against c-BM. For that reason I prefer nonc-BM. Yet, c-BM can still be saved. To see how, I will use an argument analogous to yours, chosen such that you can easily see what could be wrong with this argument:
Assume that all physicists are conscious. Also, let us assume that only one of them correctly interprets quantum mechanics. (For all others, their interpretation is at best only partially correct.) Let us call this right guy - Dmitry67. However, if you pick randomly any physicist, you have almost no chance to pick up Dmitry67. Isn't it an argument against the assumption that all physicists are conscious and that only Dmitry67 is right?

 

[Dmitry67]

At first, I deny the resemblance between your analogy with physicists and with MWI/BM – individual histories different physicists are non-intersecting lines, while I or YOU in this context is a TREE. But it is not important. We both agree that c-BM misses the main point of BM – elimination of extra branches.

So about nonc-BM. Do you agree that it is some kind of black magic associated with nonc-BM? ‘real’ observer observing ‘real’ object finds the same as empty observer observing empty system. Everything is the same and yet – empty observer is not conscious (*) – some kind of a modern vis vitalis – magic ingredient required to create organic material from non-organic components in chemical reactions.

Do you agree that as there is no information transfer from particles back to wavefunction, then nonc-BM explicitly states that consciousness can’t be in principle derived from wavefunction. In another words, if (in Birds view) you see Universe wavefunction but don’t know the trajectories of BM particles, you can’t say where the consciousness resides.

(*) You can argue that in the ‘real’ world Born rule is obeyed, however, in an ‘empty’ world there are infinitely many branches where it is obeyed (or at least not seriously violated) too.

 

[cesiumfrog]

Dmitry, I think part of the difficulty in this discussion is that Demystifier seems to take his recipe analogy seriously. In his way, BM is an elaborate formulation of the pragmatic "shut up and calculate". The idea is that there is only one reality (just as our monkey-senses keep telling us), so QM is merely the laws governing trajectories in this one reality.

In the DCQE, for example, each particle goes through absolutely only one slit - or has one definite polarisation or whatever - and it is merely an influence of the ether that causes the particles to accumulate in a pattern or not to, and which maintains coordination between entangled partners. In principle, you could observe an interference pattern and still know which slit each particle went through - you are only thwarted by the fact all your measurement devices are also made of particles which disturb this ether as well. (This ethereal influence is not light-speed limited: nonlocality loophole for hidden variables.)

The friend that Wigner later observes may be be consistent with different versions of the friend (e.g., while the lab was isolated, the friend may have spent the time dreaming of peace and afterward forgotten doing so, or he may not remember but nonetheless have spent the time dreaming of conflicts; MWI would assert that the friend branched into numerous alternate realities and that later these particular two branches recombined), Wigner's friend was nonetheless in one particular state at each time *, never a superposition. Thus, while the superposition possibilities represented in the ether do correspond to potential conscious states of observers, most possibilities are not states that the conscious observer does experience. (Analogously, we can also describe regions of configuration space that are not physically accessible, such as the details of our consciousness in a world where we measure an isolated room warming up without any potential energy source being diminished, and nobody would ascribe real self-awareness to such regions of configuration space.)

* one potential criticism of BM is that the trajectories are not particularly classical. For example, it may be unexpectedly common for Wigner's friend (in the hour before he forgets his dream and leaves to visit Wigner) to spend five minutes dreaming of peace, and then suddenly switch to the middle of a dream about conflicts, but simultaneously have his memory switch so that for the moment he falsely remembers his last five minutes being taken up by the beginning of the dream about conflicts. (To the MWI proponent BM seems unmotivating in that the fundamental theory has first been made more complicated to avoid contradicting with the monkey-notion of reality, and then been found still inconsistent with the same notion anyway; it seems more enlightened to drop such notions from the outset.)

If we could make a telephone to communicate somehow with parallel (BM might say ethereal) worlds, I think Demystifier would still maintain that it is only us that are real (and conscious), http://en.wikipedia.org/wiki/Philosophical_zombie" the "voices of ethereal possibility" may claim the reverse. To MWI this seems perverse, but perhaps that's a little unfair since MWI might have its own problems with such a technology existing. (Dmitry, I give that link to make sure you're aware there's an existing body of literature on what seems to be a core issue you two are debating.)

 

[Dmitry67]

casiumfrog, you are reading my mind. And in fact, I had mentioned P-zombies before. In nonc-BM people in 'empty' branches are exactly what is called P-zombie.

At least I think it is very important to distinguish 2 flavors of BM: c- and nonc-. Otherwise it becomes very confusing when BM proponents switch from 'wavefunction is absolutely real' to 'only one reality exists'. Without explicitly specifying flavor (c- or nonc-) it forms - how is it called - a "squishy argument"? The same was in CI, which also has 2 hidden flavors, when "wavefunction is real" and in the very next sentence "it is just a knowledge about the system"

 

[Demystifier]

Dmitry, I think part of the difficulty in this discussion is that Demystifier seems to take his recipe analogy seriously. In his way, BM is an elaborate formulation of the pragmatic "shut up and calculate". The idea is that there is only one reality (just as our monkey-senses keep telling us), so QM is merely the laws governing trajectories in this one reality.

You are absolutely right! That's exactly how I view BM. You explained it even better than I did. In particular, I would never have the courage to say that "BM is an elaborate formulation of the pragmatic shut up and calculate", but that's exactly what BM is in my view. Thanks!

 

[Demystifier]

So about nonc-BM. Do you agree that it is some kind of black magic associated with nonc-BM? ‘real’ observer observing ‘real’ object finds the same as empty observer observing empty system. Everything is the same and yet – empty observer is not conscious (*) – some kind of a modern vis vitalis – magic ingredient required to create organic material from non-organic components in chemical reactions.

No, I do not agree. See (as cesiumfrog suggested) my recipe analogy.

Do you agree that as there is no information transfer from particles back to wavefunction, then nonc-BM explicitly states that consciousness can’t be in principle derived from wavefunction. In another words, if (in Birds view) you see Universe wavefunction but don’t know the trajectories of BM particles, you can’t say where the consciousness resides.

Yes, I agree.

 

[Demystifier]

At least I think it is very important to distinguish 2 flavors of BM: c- and nonc-.

I think it is very important to distinguish 2 flavors of physics: physics which tries to say something about consciousness and physics which doesn't. (I prefer to use the second flavor whenever possible.)

 

[Demystifier]

casiumfrog, you are reading my mind. And in fact, I had mentioned P-zombies before. In nonc-BM people in 'empty' branches are exactly what is called P-zombie.

Irrespective on BM, MWI, and quantum mechanics, I do think that P-zombies are logically possible and that they are a good argument for the claim that phenomenal consciousness and qualia cannot be explained from the known laws of physics. I recommend the book
D. Chalmers, The Conscious Mind (1995).
If there is anything magic in BM, or in MWI, or even in classical mechanics, then it is the appearance of consciousness.