Well, in MWI a clock shows all the values for which the wave function does not vanish.lugita15 said:Demystifier, instead of using the word "change", what about this: why does the clock's pointer have more than one state? Isn't it conceivable that the clock would just show a single time, and thus time would stand still so speak?
As far as I can see, neither of the answers linked by Bohm2 is written by Deutch. Can you be more specific?Quantumental said:Demystifier: what do you think of Deutsch's "answer" to this in the link supplied by Bohm2 ?
Does this make any sense or is this a "serious flaw" like Born Rule in MWI?
Demystifier said:As far as I can see, neither of the answers linked by Bohm2 is written by Deutch. Can you be more specific?
Well, that quote is essentially the same what I said that the MWI resolution of the problem of time is. So it does make sense to me, even though I find the Bohmian solution much more convincing.Quantumental said:The quote given by Bohm2 is from a chapter written by Deutsch.
Demystifier said:Well, that quote is essentially the same what I said that the MWI resolution of the problem of time is. So it does make sense to me, even though I find the Bohmian solution much more convincing.
In one of his more recent papers, Wallace points out some other problems with MWI which he tries to adress:Quantumental said:It seems the Everettians has done a good job in "solving" their problems with the exception of Born Rule (though there are several attempts).
Furthermore, and quite apart from the intrinsic interest of the question, it might be thought that we cannot be confident in any story of emergence unless we are confident what it is emerging from. Maudlin (2010), in particular, criticises the Everett interpretation for having an inappropriate micro-ontology to appropriately ground macro-level facts...In particular, normally our concepts of space and time are treated as constant between higher-level and lower-level theories, so that for (e.g.) some higher-level object to exist in spacetime region K it must be instantiated not just by any old objects and properties in the lower-level theory, but by objects and properties themselves located in K.
In sum, any theory whose physical ontology is a complete wavefunction monism automatically inherits a severe interpretational problem: if all there is the wavefunction, an extremely high-dimensional object evolving in some specified way, how does that account for the low-dimensional world of localized objects that we start off believing in, whose apparent behavior constitutes the explanandum of physics in the first place?
bohm2 said:I. Schemelzer has also raised some arguments against MWI arguing that pure wave function monism is not enough but I just skimmed through them so I'm not sure I really understand his arguments very well or if they are similar to Maudlin's?
About the relation between pilot wave beables and decoherence
http://lanl.arxiv.org/pdf/0907.5284.pdf
Why the Hamilton operator alone is not enough
http://lanl.arxiv.org/pdf/0901.3262.pdf
Pure quantum interpretations are not viable
http://lanl.arxiv.org/pdf/0903.4657.pdf
I'm not sure if there is any connection between Maudlin's position and functionalism. I've always assumed that his argument against wave function monism is based on his belief on the requirement of any theory to be able to explain the macroscopic 3-D world we are familiar with: the primitive ontology (PO). See the 2 papers by Valia Allori discussing the concept of PO:Quantumental said:Regarding Maudlins objections, I am aware of them and I have communicated with him earlier in attempts to understand these worries, but I cannot comprehend them. It seems the Bohmian camp deny functionalism and I suspect that his objection arises from this and that the emergence would become natural if he accepted functionalism. But I might be very wrong, so if I am, feel free to correct me.
Primitive Ontology and the Structure of Fundamental Physical TheoriesThe notion of primitive ontology was first proposed in Dürr et al. 1992 and Goldstein 1998, and then discussed in a little more details in Allori et al. 2008. The main idea is that all fundamental physical theories, from classical mechanics to quantum theories, share the following common structure:
-Any fundamental physical theory is supposed to account for the world around us (the manifest image), which appears to be constituted by three-dimensional macroscopic objects with definite properties.
-To accomplish that, the theory will be about a given primitive ontology: entities living in three-dimensional space or in space-time. They are the fundamental building blocks of everything else, and their histories through time provide a picture of the world according to the theory (the scientific image).
-The formalism of the theory contains primitive variables to describe the primitive ontology, and nonprimitive variables necessary to mathematically implement how the primitive variables will evolve in time.
-Once these ingredients are provided, all the properties of macroscopic objects of our everyday life follow from a clear explanatory scheme in terms of the primitive ontology.
Demystifier said:Let me use a simple analogy. If functionalism was right, then we could solve the problem of hungry people in Africa by sending them a cookbook.
In other words, in Bohmian mechanics a wave function without a particle is like a cookbook without food.
bohm2 said:Myself I'm not a big fan of functionalism. Functionalism has many problems, in my opinion.
So I go with nomological WF, just as in classical Hamilton-Jacobi mechanics I go with nomological PF (principal function), which is a solution of the Hamilton-Jacobi equation. What's wrong with that?Quantumental said:I really can't phatom that there are physicists in 2012 that do not accept functionalism.
If the wavefunction is ontological in Bohm, then the many worlds are there. You would have to go with a nomological WF to avoid it.
Demystifier said:So I go with nomological WF, just as in classical Hamilton-Jacobi mechanics I go with nomological PF (principal function), which is a solution of the Hamilton-Jacobi equation. What's wrong with that?
Perhaps we do not share the same definition of the word "functionalism". What is your definition of functionalism? For example, would you say that, according to functionalism, to have a computer program which can calculate something is the same as having the calculation of that something? (In my dictionary: yes - this is what functionalism is, and no - these two things are not the same and therefore functionalism is wrong.)Quantumental said:I never said there was anything wrong with a nomological approach, but then you do not run into problems with functionalism either. So I wonder why you reject it.
Demystifier said:Perhaps we do not share the same definition of the word "functionalism". What is your definition of functionalism? For example, would you say that, according to functionalism, to have a computer program which can calculate something is the same as having the calculation of that something? (In my dictionary: yes - this is what functionalism is, and no - these two things are not the same and therefore functionalism is wrong.)
Others like Searle would disagree with this:Quantumental said:If a computer program has all the "ingredients" necessary to do all the functions as the thing does in real life, then yes it's the same. So if I were run a fantastically complicated simulation of a mouse's mind on a supercomputer, then that would indeed be a mouse's mind. Let's take another example: imagine a desert, imagine that a infinitely unlikely sandstorm occured, where the wind would act like a pilot-wave and guide all the grains of sand in such a manner that it would be identical to a human brain with all it's processes (yes gigantic storm), why wouldn't there be thoughts in this brain? Just because it isn't what we call "biological" ?
The Problem of ConsciousnessThe computational model of consciousness stands to consciousness in the same way the computational model of anything stands to the domain being modeled. Nobody supposes that the computational model of rainstorms in London will leave us all wet. But they make the mistake of supposing that the computational model of consciousness is somehow conscious. It is the same mistake in both cases.
This is a difficult topic and hard to put in words (assuming I even understand their arguments) and I don't want to misinterpret their arguments so I'll post the relevant points made by Maudlin (including questions by Wallace) and other physicists/philosophers:Quantumental said:Why couldn't a hyperdimensional object have things in it which appear 3D? Just like a hologram is 2D but appears 3D?
Can the world be only wavefunction?He (deBroglie) gives some criticisms of Schrodinger’s theory and one of them is: what does it mean to say you have this wave function on a configuration space when there’re no configurations.
Discussion: The redundancy argument against Bohm's theoryAdvocates of the Everett interpretation of quantum mechanics have long claimed that other interpretations needlessly invoke "new physics" to solve the measurement problem. Call the argument fashioned that gives voice to this claim the Redundancy Argument, or ’Redundancy’ for short. Originating right in Everett’s doctoral thesis, Redundancy has recently enjoyed much attention, having been advanced and developed by a number of commentators, as well as criticized by a few others. Although versions of this argument can target collapse theories of quantum mechanics, it is usually conceived with no-collapse "hidden variable" interpretations in mind, e.g., modal and Bohmian interpretations. In particular, the argument is an attack against theories committed to both realism about the quantum state and realism about entities – what Bell 1987 calls "beables" – that supplement this state. Particles, fields, value states, and more have been suggested as possible ontology to supplement the quantum state. Redundancy is the argument that this supplementation is methodologically otiose, the superfluous pomp that Newton scorned.
If by "thoughts" you mean physical events which process information, then they will be there. But if by "thoughts" you mean subjective conscious experiences, then I have no idea. I pretty much agree with Chalmers that physics as we understand it cannot explain the origin of subjective conscious experiences.Quantumental said:Let's take another example: imagine a desert, imagine that a infinitely unlikely sandstorm occured, where the wind would act like a pilot-wave and guide all the grains of sand in such a manner that it would be identical to a human brain with all it's processes (yes gigantic storm), why wouldn't there be thoughts in this brain?
Just because it isn't what we call "biological" ?
bohm2 said:Others like Searle would disagree with this:
The Problem of Consciousness
http://users.ecs.soton.ac.uk/harnad/Papers/Py104/searle.prob.html
Demystifier said:If by "thoughts" you mean physical events which process information, then they will be there. But if by "thoughts" you mean subjective conscious experiences, then I have no idea. I pretty much agree with Chalmers that physics as we understand it cannot explain the origin of subjective conscious experiences.
I interpretated him as arguing that simulating some properties of the mind/brain is not the same thing as subjectivity/qualia/consciousness. I think he is just re-stating his "Chinese Room" argument:Quantumental said:I disagree with Searle here.
The problem is one of unification. How does a brain/matter with the properties we currently understand "spit out" qualia/subjectivity? You don't literally see one's thoughts using brain scans. Many think the issue is far more complex but I probably agree with you that this issue has little to say on this topic of this thread, I think.Quantumental said:yeah consciousness *seems* very mysterious and all, but it is just neural activity in the brain. We can demonstrate this by doing drugs and scanning the brain. We have in my opinion absolutely no reason to suspect that consciousness somehow taps into some unknown physics...
indeed, there is a lot of EXPERIMENTAL evidence that neural activity is correlated with consciousness. But it does not imply that we THEORETICALLY understand how one thing causes the other.Quantumental said:But why not? I mean, yeah consciousness *seems* very mysterious and all, but it is just neural activity in the brain. We can demonstrate this by doing drugs and scanning the brain.
We have in my opinion absolutely no reason to suspect that consciousness somehow taps into some unknown physics...
There are many possibilities. One of them is that particle trajectories ARE consciousness:Quantumental said:But even if you think that it may do, how does that affect the debate of whether minds can arise from a wavefunction?
Demystifier said:There are many possibilities. One of them is that particle trajectories ARE consciousness:
http://arxiv.org/abs/1112.2034
Based on past discussions with Demystifier (and he can correct me if I'm wrong), I think he rejects many worlds because it doesn't suffice to prove the Born rule for probabilities. In order to prove it, you need to make additional assumptions, and he feels that Bohmian mechanics constitutes the most plausible set of additional assumptions.Quantumental said:So why aren't you pro-MWI really? What keeps you from subscribing to it's plausibility?
Yes, that's correct.lugita15 said:Based on past discussions with Demystifier (and he can correct me if I'm wrong), I think he rejects many worlds because it doesn't suffice to prove the Born rule for probabilities. In order to prove it, you need to make additional assumptions, and he feels that Bohmian mechanics constitutes the most plausible set of additional assumptions.
Yes, I only wanted to demonstrate a point. But I know an even more crazy idea by a serious philosopher of physics which only serves to demonstrate a point. Do you know about the Albert fatness argument against the Born rule in MWI?Quantumental said:This hypothesis might be the most crazy thing I've ever heard from a serious physicist.
I hope you made that paper to demonstrate a point and not that you actually consider it a serious possibility.
Superdeterminism ('t Hooft is waaay less crazy)
A careful reader may notice that some of my papers are quite MWI in spirit:Quantumental said:But I wanted to ask you something: you seem quite liberal with your ideas and open to a lot of speculation. So why aren't you pro-MWI really?
Demystifier said:Yes, I only wanted to demonstrate a point. But I know an even more crazy idea by a serious philosopher of physics which only serves to demonstrate a point. Do you know about the Albert fatness argument against the Born rule in MWI?
Quantumental said:I wish Ilja still posted here, I remember a few threads where he participated and his opinions seemed to be very interesting, but I never fully grasped them.
Why MWI?MWI in it's current form simply becomes invalid, with or without Born rule, because it does not have an additional structure which is necessary to fix the preferred basis: The papers prove that different choices are possible, and lead to different physics. The Copenhagen intepretation solves this problem with its association of the operators p, q with classical experimental arrangements, but this solution is not available in the Everett interpretation. Thus, to make MWI a (viable) intepretation, you not only have to derive the Born rule, but also have to add some new structure to fix the canonical preferred basis.
Why the Hamilton operator alone is not enoughInstead, recognizing that the configuration space is part of the definition of the physics gives more power to an old argument in favour of the pilot wave approach, made already by de Broglie at the Solvay conference 1927: “It seems a little paradoxical to construct a configuration space with the coordinates of points which do not exist.”
I only wanted to point out that this idea is even more crazy than mine. :tongue2:Quantumental said:Yes I'm aware of it. But I thought David Wallace had responded to it?
bohm2 said:Ilja did discuss his criticism of MWI in this blog:
Why MWI?
http://onqm.blogspot.ca/2009/07/why-mwi.html
My first impressions is that he is echoing Maudlin's arguments but presenting them more formally, I think? Notice that Ilja also quotes deBroglie as per Valentini in that video I linked using the same type of argument:
Why the Hamilton operator alone is not enough
http://arxiv.org/pdf/0901.3262.pdf
I've e-mailed Ilja. Maybe he will comment.Quantumental said:I know Ilja has been on PF.com previously, it would be cool if he came back and commented some on this. Personally I am not qualified to judge this, but I do find it interesting that it seems only 2 people bring up this...Mallah also argues quite confidently against it
bohm2 said:Ilja did discuss his criticism of MWI in this blog:
Why MWI?
http://onqm.blogspot.ca/2009/07/why-mwi.html
My first impressions is that he is echoing Maudlin's arguments but presenting them more formally, I think? Notice that Ilja also quotes deBroglie as per Valentini in that video I linked using the same type of argument:
Why the Hamilton operator alone is not enough
http://arxiv.org/pdf/0901.3262.pdf
Ilja said:My argument about the Hamilton operator is indeed more formal, but it is also about a slightly different point than Maudlin. In the video lecture which has been linked here, he was ready to accept the configuration space as given as an additional structure. Then, one main argument is that the configuration space itself requires much more structure.
My point is that without additional structure you cannot identify the configuration space. This was an important point for me because it destroys claims that MWI needs less structure.