Let us assume Feynman was wrong.

[Spinnor]

After summing up the rudiments of quantum mechanics Feynman tries to answer a question that readers might have at this point of his book, The Feynman Lectures on Physics, Vol. III, page 1-10.1. He writes,

"One might still like to ask: "How does it work? What is the machinery behind the law?" No one has found any machinery behind the law. No one can "explain" any more than we have just "explained". No one will give you any deeper representation of the situation. We have no ideas about a more basic mechanism from which these results can be deduced. ... "

Assume Feynman was wrong, please give me a deeper representation of the situation.

Thank you for your thoughts.

 

[benk99nenm312]

After summing up the rudiments of quantum mechanics Feynman tries to answer a question that readers might have at this point of his book, The Feynman Lectures on Physics, Vol. III, page 1-10.1. He writes,

"One might still like to ask: "How does it work? What is the machinery behind the law?" No one has found any machinery behind the law. No one can "explain" any more than we have just "explained". No one will give you any deeper representation of the situation. We have no ideas about a more basic mechanism from which these results can be deduced. ... "

Assume Feynman was wrong, please give me a deeper representation of the situation.

Thank you for your thoughts.

Assuming Feynman was wrong leaves us with theories. I have my own; I don't like to share it over the internet (sorry, nothing personal, I'm just not comfortable with being to open about it). I don't think most would be.

I can tell you this: if you want to know why a particle has probabilities of being in different places or states, then Quantum Mechanics is the last place to look. QM is all about math, probability amplitudes, wave/ particle duality. This is an explanation of what happens, not why it happens. So, in my opinion, there has to be an underlying cause, where one measures what QM states should happen, but the actual action of the particles is based on principles which one might need to invent. Einstein had this kind of thought. General Relativity was a huge leap that described nature. There has to be one for QM too. As far as what it is, I have used certain principles of Relativity. My personal thoughts are that we don't need to quantify gravity; we need to relativize QM.

 

[friend]

"One might still like to ask: "How does it work? What is the machinery behind the law?" No one has found any machinery behind the law. No one can "explain" any more than we have just "explained". No one will give you any deeper representation of the situation. We have no ideas about a more basic mechanism from which these results can be deduced. ... "

Assume Feynman was wrong, please give me a deeper representation of the situation.

Thank you for your thoughts.

What you seem to be asking for is a derivation of QM from more basic principles. What more basic principles could there possibly be? By definition basic principles apply to a broad range of situations, and not just a few. And I suppose that the most basic principles that apply to everything are the principles of logic and reason. I don't believe that anyone is going to argue that there is anything in reality that does not comply with reason, is there? So I have to wonder if the laws of physics (QM, in this case) can be derived from logic. If physics could be derived from logic, then that would be the completion of physics. We would no longer be able to question where physics came from since the answer would be that it comes from reason itself, and how do you question that?

 

[DaveLush]

Spinnor, (and everyone) did you know there is a school of thought that quantum behavior is simply the result of classical (but relativistic) elecytrodynamics when done properly. By properly here I mean including the effects of delay and radiation damping.

Here is an example paper, that was published in the peer-reviewed literature (Found. Phys. 34 (2004) 937--62), "The electrodynamic 2-body problem and the origin of quantum mechanics", C. K. Raju, on arxiv here: http://arxiv.org/abs/quant-ph/0511235 . Within the rules here I cannot cite everything I would like. There are more papers on arxiv than have made it into print as of yet. A very important paper in this area is one by Jayme De Luca, Physical Review E, vol. 73, 026221 (2006), "Stiff three-frequency orbit of the hydrogen atom ", on arxiv here: http://arxiv.org/abs/physics/0511179 .

On arxiv if you click the author name on the abstract pages you will see all the other papers by that author in the category of the abstract.

Also I could recommend many other mainstream peer-reviewed journal articles. A good approach is to look at the references in those two papers. Many of them are too old to be on arxiv but you may find more recent papers there by some of the authors. David Hestenes' published works are posted on his website (along with applicable mainstream peer-reviewed journal citations) which may be navigated to from the wikipedia article about him.

 

[Demystifier]

Assume Feynman was wrong, please give me a deeper representation of the situation.

A possible deeper representation is provided by the Bohmian (pilot wave) interpretation. In particular, the recent lectures presented here:
http://www.tcm.phy.cam.ac.uk/~mdt26/pilot_waves.html
emphasize the point that Feynman was wrong that a deeper explanation is not possible.

 

[Dmitry67]

Actually, any interpretation does the same. BTW Feynman preferred 'shut up and calculate' interpretation.

 

[dx]

Feynman was not wrong. There are no widely accepted ideas from which quantum mechanics can be deduced.

 

[p764rds]

After summing up the rudiments of quantum mechanics Feynman tries to answer a question that readers might have at this point of his book, The Feynman Lectures on Physics, Vol. III, page 1-10.1. He writes,

"One might still like to ask: "How does it work? What is the machinery behind the law?" No one has found any machinery behind the law. No one can "explain" any more than we have just "explained". No one will give you any deeper representation of the situation. We have no ideas about a more basic mechanism from which these results can be deduced. ... "

Assume Feynman was wrong, please give me a deeper representation of the situation.

Thank you for your thoughts.

Wheeler was closest with 'we all live in a giant computer' - if this is the case its all quite easy to understand. It needs an 'information space' from which data 'creates' ordinary thee dimensional space and objects within it.
This information lies outside space but has time IMO).
But its hard to swallow that we are all made of 0s and 1s - as is space itself. There are few takers of this theory but to me its blindingly obvious.

 

[jtbell]

I think Feynman's quote refers to the fact that there is no generally accepted interpretation of QM. Lots of people certainly do have ideas about what "lies behind" the mathematics of QM. The problem is that there are a bunch of different interpretations, and no way (so far) to decide among them by experiment, because they're constructed to reduce to the standard mathematics of QM for predictions of the results of actual experiments.

 

[camboy]

Feynman was not wrong.

I'm afraid he was. Most of Feynman's sweeping statements about QM for a general audience refer to the two-slit experiment. He devotes nineteen pages of The Character of Physical Law to this - with repeated statements such as 'Many ideas have been concocted to try to explain [this interference pattern] in terms of individual electrons going round in complicated ways through holes. None of them has succeeded.' and 'A phenomenon which is impossible, absolutely impossible to explain in any classical way.. in reality it contains the only mystery'. This is as well as your 'How does it really work? What machinery is actually producing this thing? Nobody knows any machinery.'

What Demistifyer is saying (and I followed that lecture course as well) is that de Broglie-Bohm pilot-wave theory (which basically says there is a particle and a wave') provides exactly the machinery that Feynman says is 'absolutely impossible.' It doesn't matter whether pilot-wave theory has anything to do with reality or not. The point is that Feynman says no-one knows any machinery - but they do.
And that's interesting - particularly as Feynman knew Bohm well - (see Towler's Lecture 7). Presumably he just had a simple message which he wanted to convey (the two-slit experiment is not visualizable in QM terms) and he just wanted to stick to that.

As John Bell said:

'Is it not clear from the smallness of the scintillation on the screen that we have to do with a particle? And is it not clear, from the diffraction and interference patterns, that the motion of the particle is directed by a wave? De Broglie showed in detail how the motion of a particle, passing through just one of two holes in the screen, could be influenced by waves propagating through both holes. And so influenced that the particle does not go where the waves cancel out, but is attracted to where the cooperate. This idea seems to me so natural and simple, to resolve the wave-particle dilemma in such a clear and ordinary way, that it is a great mystery to me that it was so generally ignored.'

So basically pilot-wave theory has the same results as QM, but it has the advantage of having qualitative explanations and 'mechanism' as well. There's got to be something to be said for making things comprehensible for students surely..? But the violent vituperation that has been dumped on this theory since its pre-Copenhagen proposal - (just because it shows many of the impossibility statements by the Founding Fathers to be profoundly mistaken, and we're not allowed to be rude about them) - is extraordinary.

Remember Bohr's definition of complementarity: 'There is no logical picture (obeying classical propositional logic) that can simultaneously describe and be used to reason about all properties of a quantum system.' - essentially because of the incompatibility of wave and particle descriptions. Er.. except if - as de Broglie said - if you have waves and particles then everything is obvious - but somehow they missed that.. Hmmm.

 

[dx]

As I said, there's no widely accepted way to deduce quantum mechanics from more fundamental ideas or to provide some classical mechanism. Bohm's theory has many problems, and is at best redundant, but let's not turn this into a discussion of that.

 

[camboy]

As I said, there's no widely accepted way to deduce quantum mechanics from more fundamental ideas or to provide some classical mechanism. Bohm's theory has many problems, and is at best redundant, but let's not turn this into a discussion of that.

[Amused grin]

So Feynman says nobody knows any machinery.

I point out that somebody does know some machinery.

You imply that this is irrelevant, because not many people know this, therefore Feynman is correct, and thus nobody knows any machinery.

I love your logic!

[PS: I agree - it serves no purpose. to discuss pilot-wave theory here - if people are interested they can read the lecture notes Demystifier referred to. But, just for the record, there are no problems with it that anyone has ever been able to substantiate - as always it is just a matter of opinion. However, it does provide machinery - so really what you are saying is that 'machinery' itself is redundant - not just that Bohm's (in fact de Broglie's) theory is redundant. A fair number of people would disagree with you on that, but of course you don't care, and why would you...? ]

 

[dx]

so really what you are saying is that 'machinery' itself is redundant - not just that Bohm's (in fact de Broglie's) theory is redundant.

I'm not saying machinery is redundant. I'm saying there's no machinery behind quantum mechanics that is widely accepted. I'm sure you know that there are a lot of disagreements among physicists about Bohm's theory, and it is a controversial thing. It certainly claims to provide a machinery for QM, but it is not a settled issue. That's all I'm saying.

 

[Dmitry67]

I think Max Tegmark is right
There is no machinery at all, just equations.
Ultimately, "**** up and calculate" is right - not as a denial to understand the underlying machinery, but as understanding that there is no machinery at all.

P.S.
Hm... the famous Feynman interpretation is automatically replaced with ****...

 

[camboy]

I'm not saying machinery is redundant. I'm saying there's no machinery behind quantum mechanics that is widely accepted.

Christ - the philosophers would have a field day with you..

The Original Poster quotes Feynman as saying 'nobody knows any machinery' - a statement which we now know is incorrect.

You state that Feynman is not incorrect - he is correct. Thus you imply 'nobody knows any machinery'.

As long as the relevant machinery is not demonstrably false (which it isn't) the logical flow here has nothing to do with how 'widely accepted' the machinery is, so I fail to see what point you are trying to make.

The machinery Demystifer and I referred to is fully compatible with all observations, so one cannot rule out that machinery of this nature genuinely exists.. And since it makes comprehensible the 'reality of a quantum event', one might as well imagine this to be the case while we await further evidence. At the very least freshman students would be less confused..[PS: Look - I can edit my own post to make it look better after people reply to it as well!]

 

[camboy]

I think Max Tegmark is right
There is no machinery at all, just equations.
Ultimately, "**** up and calculate" is right - not as a denial to understand the underlying machinery, but as understanding that there is no machinery at all.

Just so long as we understand that 'there is no machinery at all' is an interpretation just like any other.

(And in my opinion a damned unlikely one - otherwise why does anything do anything? )

P.S.
Hm... the famous Feynman interpretation is automatically replaced with ****...

Now I wonder if you mistyped 'shut' as '****' (just testing).

 

[Dmitry67]

And in my opinion a damned unlikely one - otherwise why does anything do anything? )

Check Max Tegmarks "Mathematical Universe"
Just equations, and nothing else.
The questions about the "machinery" behind are silly, like "what numbers are made of?"

 

[dx]

I think Max Tegmark is right
There is no machinery at all, just equations.
Ultimately, "**** up and calculate" is right - not as a denial to understand the underlying machinery, but as understanding that there is no machinery at all.

P.S.
Hm... the famous Feynman interpretation is automatically replaced with ****...

That's another common misunderstanding of what "interpretations of quantum mechanics" are about. It's not a pointless desire to visualize some "machinery" behind the equations. Theories of physics consist of two parts. One is a mathematical structure M, and the other is a way to relate that structure to experience, i.e. a map from experience to the mathematical structure. In all the theories discovered before quantum mechanics, the "interpretation" part was obvious, and never needed to be explicitly discussed. No one needed to tell you what a world-line was when you learned special relativity. It was clear what the elements of the mathematical structure of SR like events, world-lines etc. corresponded to in experience. This changed in QM. For many problems of practical interest, one knew how to apply QM. But it wasn't so clear in all cases. This is the problem of the interpretation of quantum mechanics. To define unambiguously how to relate the mathematical structure of QM to experience.

 

[dx]

The Original Poster quotes Feynman as saying 'nobody knows any machinery' - a statement which we now know is incorrect.

Do we also know that special relativity is wrong? Many crackpots claim it is. I think it's pretty clear that what Feynman meant was that no machinery that is widely accepted has been found.

[PS: Look - I can edit my own post to make it look better after people reply to it as well!]

I have no idea what you're talking about.

 

[dx]

Also, you keep saying Bohm's mechanics is fully compatible with observations. I don't want to turn this into a discussion of this theory, but you don't seem to get that not everyone agrees with this view . You may agree with it, but it is not established fact.

 

[camboy]

That's another common misunderstanding of what "interpretations of quantum mechanics" are about. It's not a pointless desire to visualize some "machinery" behind the equations. Theories of physics consist of two parts. One is a mathematical structure M, and the other is a way to relate that structure to experience, i.e. a map from experience to the mathematical structure. In all the theories discovered before quantum mechanics, the "interpretation" part was obvious, and never needed to be explicitly discussed. No one needed to tell you what a world-line was when you learned special relativity. It was clear what the elements of the mathematical structure of SR like events, world-lines etc. corresponded to in experience. This changed in QM. For many problems of practical interest, one knew how to apply QM. But it wasn't so clear in all cases. This is the problem of the interpretation of quantum mechanics. To define unambiguously how to relate the mathematical structure of QM to experience.

Well, indeed. But I think the point of the pilot-wave theorists is that their interpretation is the obvious one - so obvious that it was the first interpretation introduced (presented in its complete many-body form by de Broglie in 1927 - apart from some minor issues about measurement - which is why it isn't really Bohm's theory at all).

They would then point out that Bohr and co muddied the water completely by insisting on the validity of their weird philosophical ideas (based on the then fashionable and since thoroughly discredited ideas of logical positivism) and from that standpoint they ridiculed de Broglie (an electron can't have a trajectory because you can't measure it!). Since Bohr and co then acquired the status of quantum deities - no-one felt able to question them for another thirty years and de Broglie's stuff was completely forgotten.

By the time Bohm reintroduced exactly the same scheme in the 1950s - it was ignored - since it so flatly contradicted everything Bohr et al said it couldn't be true. As Oppenheimer said - 'if we cannot disprove Bohm we must agree to ignore him'.

When it was generally realized that Copenhagen was logically inconsistent (let's not get into an argument about this) - people then felt able to introduce any damned scheme they wanted to - because they thought the 'obvious' interpretation had been disproved, which it hadn't.

 

[Dmitry67]

well, at least there are some good news: I mean, the relatively recent discovery of the Quantum Decoherence. It demonstrated that most or all 'classical' behavior can be derived directly from the 'pure' (interpretation-less) QM

 

[camboy]

Do we also know that special relativity is wrong? Many crackpots claim it is. I think it's pretty clear that what Feynman meant was that no machinery that is widely accepted has been found.

Like most dogmatists, you are probably unaware that special relativity has at least three interpretations compatible with experiment (including one that has (gulp) an 'ether'). So saying, for example, that it is an established fact that there is no preferred reference frame would be wrong. [I admit I learned this recently myself - see http://www.tcm.phy.cam.ac.uk/~mdt26/pilot_waves.html's Lecture 5].

And I disagree - what Feynman states quite clearly is that 'nobody knows any machinery.' If you want to hear him repeating this statement in about 85 different ways, read the 19 pages of The Character of Physical Law that I referred to earlier. It is irrelevant whether a valid machinery for (say) explaining the two-slit experiment is widely accepted or otherwise. He says - quite explicitly - that it is impossible to come up with a 'mechanism' compatible with the experimental results. That is clearly not the case.

 

[camboy]

well, at least there are some good news: I mean, the relatively recent discovery of the Quantum Decoherence. It demonstrated that most or all 'classical' behavior can be derived directly from the 'pure' (interpretation-less) QM

God - you people might as well just paint a target on your forehead and say 'shoot me'.

The concept of decoherence was in fact introduced in 1952 by Bohm himself.. (Is 57 years ago 'relatively recent'?). This was essentially the only thing he added to de Broglie's 1927 pilot-wave theory (in order to explain the irreversibility of measurements when amplified to the macroscopic scale..).

And look, blithely insisting that the statement 'QM has no interpretation' is somehow uniquely philosophically privileged as not itself being an interpretation itself is crazy. Every other theory has one - how does QM get away with it?

 

[Dmitry67]

And look, blithely insisting that the statement 'QM has no interpretation' is somehow uniquely philosophically privileged as not itself being an interpretation itself is crazy. Every other theory has one - how does QM get away with it?

it is not exactly about QM but about TOE:
http://arxiv.org/PS_cache/arxiv/pdf/0704/0704.0646v2.pdf
page 2, mostly this:

All these theories have two components: mathematical equations and “baggage”, words that explain how they are connected to what we humans observe and intuitively understand. Quantum mechanics as usually presented in textbooks has both components: some equations as well as three fundamental postulates written out in plain English.

...
As an extreme example of a “theory”, the description of external reality found in Norse Mythology involves a gigantic tree named Yggdrasil, whose trunk supports Earth. This description all on its own is 100% baggage, since it lacks definitions of “tree”, “Earth”, etc. Today, the baggage fraction of this theory could be reduced by describing a tree as a particular arrangement of atoms, and describing this in turn as a particular quantum field theory state.

...

However, could it ever be possible to give a description of the external reality involving no baggage? If so, our description of entities in the external reality and relations between them would have to be completely abstract, forcing any words or other symbols used to denote them to be mere labels with no preconceived meanings whatsoever. A mathematical structure is precisely this: abstract entities with relations between them.

...
Crudely speaking, the ratio of equations to baggage decreases as we move down the tree, dropping near zero for highly applied fields such as medicine and sociology. In contrast, theories near the top are highly mathematical, and physicists are still struggling to articulate the concepts, if any, in terms of which we can understand them. The MUH implies that the TOE indicated by the question mark at the top is purely mathematical, with no baggage whatsoever.

 

[camboy]

Also, you keep saying Bohm's mechanics is fully compatible with observations. I don't want to turn this into a discussion of this theory, but you don't seem to get that not everyone agrees with this view . You may agree with it, but it is not established fact.

It doesn't matter whether everyone agrees with this view or not (in fact - given the existence of nutters - not everyone agrees with anything - so using this as a criterion could be used to disprove the whole of physics).

If you can point to a paper in the literature where an observation is made that is incompatible with 'Bohm theory' then you would have an argument. Now I haven't reviewed the whole literature myself (I just went to a lecture course) so perhaps such a paper exists. I am thus interested to hear what observations you are referring to?

One sees this would be particularly interesting when you understand that (as Towler repeatedly says in his lectures) - 'Bohm theory' is just ordinary QM with a single change in the meaning of one word, i.e. probability means 'the probability of a particle being at x' rather than 'the probability of a particle being found at x in a suitable measurement'.

I think any observations incompatible with that would thus be incompatible with QM as a whole, and would thus be very interesting indeed..

 

[dx]

And I disagree - what Feynman states quite clearly is that 'nobody knows any machinery.'

Yes, nobody knows any machinery. Nobody knows any machinery that is widely accepted . I don't mind repeating the same thing again and again, but it's getting a little annoying. Feynman didn't say the part in bold, but I think it's obvious that's what he meant. Whether you think the "widely accepted" part is relevant or not, that's what I think Feynman meant.

 

[dx]

One sees this would be particularly interesting when you understand that (as Towler repeatedly says in his lectures) - 'Bohm theory' is just ordinary QM with a single change in the meaning of one word, i.e. probability means 'the probability of a particle being at x' rather than 'the probability of a particle being found at x in a suitable measurement'.

That's an over simplification. Read this for a discussion of the many problems with Bohm theory: http://motls.blogspot.com/2009/01/bohmists-segregation-of-primitive-and.html

 

[camboy]

it is not exactly about QM but about TOE:
http://arxiv.org/PS_cache/arxiv/pdf/0704/0704.0646v2.pdf
page 2, mostly this:

Come on - you don't need to cite a paper to adopt this viewpoint. All you're really saying is that we can never know for certain whether any 'interpretation' we place on mathematics has any bearing on what 'really exists'. This is about as obvious a statement as one can make on the issue. Clearly one can never know this.

The point is - what viewpoint is convenient for understanding the behaviour of the systems we are trying to model mathematically?

Assuming Newtonian mechanics is sufficient to put a spacecraft in orbit around Mars - one say that x represents the position of a spacecraft and v represents it's trajectory and no-one argues about that. No-one says - this is just an algorithm which tells me where to point the spacecraft and how long to burn the thrusters.

In non-relativistic QM, the argument of the wave function in the Schrodinger equation looks like a configuration of particles. If you say that it does represent an actual configuration of particles then you get a clear - even banal - theory with no paradoxes- which is essentially just statistical mechanics with a new form of dynamics. If you adopt some other viewpoint you either end up with the 'bizarre mind-boggling spooky paradoxical quantum world where cats are alive and dead at the same time in many universes at once!' theory that is all the general public knows about QM, or like you one denies that the theory has an interpretation at all and is just an algorithm for reproducing experimental results (which is a perfectly respectable viewpoint - it's just a bit boring).

Returning to the point of the Original Post - some people argue that Feynman himself is largely responsible for this 'quantum mechanics is weird' attitude. See Holland's paper in Nature: "Quantum weirdness. How much of the strangeness lies in Feynman's legacy of catchphrases?" from the year 2000.

 

[camboy]

Yes, nobody knows any machinery. Nobody knows any machinery that is widely accepted . I don't mind repeating the same thing again and again, but it's getting a little annoying. Feynman didn't say the part in bold, but I think it's obvious that's what he meant. Whether you think the "widely accepted" part is relevant or not, that's what I think Feynman meant.

Look - me and the original poster are talking about what Feynman actually wrote - which I believe I have demonstrated to be incorrect.

You are talking about what you think was in Feynman's head when he wrote it, which is a matter for mediums who can communicate with the dead.

As you say, let's leave this there.

 

[camboy]

That's an over simplification.

No it isn't.

Read this for a discussion of the many problems with Bohm theory: http://motls.blogspot.com/2009/01/bohmists-segregation-of-primitive-and.html

Oh God - you're a Motl fanboy. Look - you must know that hiding behind Lubos's skirts really is the last refuge of the scoundrel. We all know he simply attacks anything that isn't string theory on principle in such a vicious one-sided way basing his knowledge (it seems) on glancing through poor-quality Wikipedia articles.

In fact his criticisms of pilot-wave theory are all either incorrect, or matters of (loudly expressed) opinion. There was a Ph.D. student (Maaneli) who bravely took him on during some of his earlier anti-Bohm rants and he suggested Lubos might benefit from reading the literature. Sadly the suggestion was not followed.

If, instead, you want a 'discussion of the many problems with Lubos Motl', then read http://backreaction.blogspot.com/2007/08/lubo-motl.html" .

Stealing one of the more relevant quotes on the page:

To paraphrase John Baez, it isn't easy to ignore Lubos, but it is always worth the effort.

 

[dx]

No it isn't.



Oh God - you're a Motl fanboy. Look - you must know that hiding behind Lubos's skirts really is the last refuge of the scoundrel. We all know he simply attacks anything that isn't string theory on principle in such a vicious one-sided way basing his knowledge (it seems) on glancing through poor-quality Wikipedia articles.

In fact his criticisms of pilot-wave theory are all either incorrect, or matters of (loudly expressed) opinion. There was a Ph.D. student (Maaneli) who bravely took him on during some of his earlier anti-Bohm rants and he suggested Lubos might benefit from reading the literature. Sadly the suggestion was not followed.

If, instead, you want a 'discussion of the many problems with Lubos Motl', then read http://backreaction.blogspot.com/2007/08/lubo-motl.html" .

Stealing one of the more relevant quotes on the page:

To paraphrase John Baez, it isn't easy to ignore Lubos, but it is always worth the effort.

I don't see any physics in this post.

 

[camboy]

I don't see any physics in this post.

Look - we're trying (admittedly not very successfully) to prevent this turning into a discussion about pilot-wave theory. What do you want me to do? - go through Lubos's voluminous anti-Bohm posts and pick out one by one all the errors, misunderstandings, and distortions and explain them. I didn't think so. I don't have the time to write such a post, and you don't have the time to read it. If you have an actual physics issue you want to raise, please feel free to do so.

And I think it's a bit rich of you to say that - for the first time if you look back - there is no physics in my last post. The post from you that I was responding to says 'that's an over-simplification' (with no physics argument to say why you think this) and - effectively - 'Lubos Motl doesn't like it' (a content-free assertion of authority). In fact now I come to think of it almost all your contributions to this thread have been along the lines of 'not everyone agrees with it' and in fact, whilst continually criticizing pilot-wave theorists you haven't come with an argument of your own at all to state why you don't like it. Do you actually understand what it is or am I missing something?

 

[dx]

And I think it's a bit rich of you to say that - for the first time if you look back - there is no physics in my last post. The post from you that I was responding to says 'that's an over-simplification' (with no physics argument to say why you think this) and - effectively - 'Lubos Motl doesn't like it' (a content-free assertion of authority).

I didn't just say "Lubos Motl doesn't like it". I gave you a link to a page where he gives his reasons.

In fact now I come to think of it almost all your contributions to this thread have been along the lines of 'not everyone agrees with it'

Yes, and that was the only contribution I intended to make, before you started creating straw men.

and in fact, whilst continually criticizing pilot-wave theorists you haven't come with an argument of your own at all to state why you don't like it.

I explicitly stated in my original reply that I don't want to get into a discussion of pilot-wave theory, and all I was saying was that not everyone agrees with it. That was my only point.

 

[camboy]

I didn't just say "Lubos Motl doesn't like it". I gave you a link to a page where he gives his reasons..

..in the form of a loud, confusing, and largely incorrect rant.

I explicitly stated in my original post that I don't want to get into a discussion of pilot-wave theory, and all I was saying was that not everyone agrees with it. That was my only point.

Well indeed - Mr. dx.

Not a very good point though, is it?

 

[Demystifier]

To conclude:
Perhaps what Feynman meant was correct (we shall never know), but what he actually said was clearly wrong, because some people (who are professional physicists by the way) claim that they know a possible mechanism.

 

[Dmitry67]

All you're really saying is that we can never know for certain whether any 'interpretation' we place on mathematics has any bearing on what 'really exists'. This is about as obvious a statement as one can make on the issue. Clearly one can never know this.

The point is - what viewpoint is convenient for understanding the behaviour of the systems we are trying to model mathematically?

Yes and no, there are 2 different things: interpretation and the "machinery". Many, but not all interpretations explicitly describe the machinery behind, like "knowledge of an observer collapses the wavefuction" or "wave guides the particle inside" et cetera. When I hear about the "knowledge of an observer" I always think about the "gigantic tree named Yggdrasil, whose trunk supports Earth" (c) - the example I gave above.

Why "observer's knowledge" is supposed to be less complex object then Yggdrasil or a turtle staying on a whale?

So, why I say that machinery and interpretations are not the same? Because not all who adopt the MWI or "Shut up and calculate" accept Max Tegmark's "Mathematical Universe Hypotesis" (MUH).

So there is a difference from what you say "we can never know for certain whether any 'interpretation' we place on mathematics has any bearing on what 'really exists'" and MUH.

As a MUH proponent I can say that:
1. It is know about not being possible to know for certain what machinery behind is right: it is about an absence of any machinery (except formulas).
2. Physics IS mathematics on the fundamental level, so the there is no difference in principle between the mathematics (adequate to our universe) and "what 'really exists'"

But over and over people ask "what is a wavefunction? what is space made of? are virtual particles real?" trying to discover wheels and rubber bands behind the curtain.

 

[Fra]

Assume Feynman was wrong, please give me a deeper representation of the situation.

I think Feynman was just stating the fact that no one did in fact have a deeper explanation. I think that was correct. That doesn't mean however that this will always be the case.

I can acknowledge my instant ignorance at the same time that I defend my ability to learn.

What you seem to be asking for is a derivation of QM from more basic principles. What more basic principles could there possibly be? By definition basic principles apply to a broad range of situations, and not just a few. And I suppose that the most basic principles that apply to everything are the principles of logic and reason. I don't believe that anyone is going to argue that there is anything in reality that does not comply with reason, is there? So I have to wonder if the laws of physics (QM, in this case) can be derived from logic. If physics could be derived from logic, then that would be the completion of physics. We would no longer be able to question where physics came from since the answer would be that it comes from reason itself, and how do you question that?

I think most sane persons would agree that scientific knowledge doesn't follow deductively from logic. But some people think that the scientific process as well as physical processes itself is to be thought of as inducive information processes.

Not the answer, not even close, but a good start and thought provocations mad enough to be brilliant...

From Inference to Physics, Ariel Caticha
"Entropic dynamics, a program that aims at deriving the laws of physics from standard probabilistic and entropic rules for processing information, is developed further. We calculate the probability for an arbitrary path followed by a system as it moves from given initial to final states. For an appropriately chosen configuration space the path of maximum probability reproduces Newtonian dynamics."
--http://arxiv.org/abs/0808.1260

The Information Geometry of Space and Time, Ariel Caticha
" Is the geometry of space a macroscopic manifestation of an underlying microscopic statistical structure? Is geometrodynamics - the theory of gravity - derivable from general principles of inductive inference? Tentative answers are suggested by a model of geometrodynamics based on the statistical concepts of entropy, information geometry, and entropic dynamics. The model shows remarkable similarities with the 3+1 formulation of general relativity. For example, the dynamical degrees of freedom are those that specify the conformal geometry of space; there is a gauge symmetry under 3d diffeomorphisms; there is no reference to an external time; and the theory is time reversible. There is, in adition, a gauge symmetry under scale transformations. I conjecture that under a suitable choice of gauge one can recover the usual notion of a relativistic space-time."
-- http://arxiv.org/abs/gr-qc/0508108

In that paper ha raises the idea

"...The connection between physics and nature could, however, be less direct. The laws
of physics could be mere rules for processing information about nature..."

He continuous and develops a tradition from ET Jaynes, the author of the book

Probability Theory: The Logic of Science
-- http://bayes.wustl.edu/etj/prob/book.pdf

He also has a related reasoning in

"Consistency, Amplitudes and Probabilities in Quantum Theory"
-- http://arxiv.org/abs/quant-ph/9804012

I do not personally quite like that paper however. His choice of reasoning is not unique IMO, and the complex formalism is imlplicitly assumed.

But Ariels general idea is that the laws of physics doesn't follow from deductive logic, but possibly from inductive reasoning... and I think it's close. Close to the ideas on evolving law in the other thread.

/Fredrik

 

[friend]

I think most sane persons would agree that scientific knowledge doesn't follow deductively from logic.

I see no basis for this statement. Are we going to say at some level of physics that it does not comply with logic? If not, and everything does comply with logic, then everything is actually derived from logic. For otherwise, you have the situation where you stop at some particle or situation saying there is no reason for it. But to say that EVERYTHING is reasonable is equivalent to saying that everything can ultimately be derived from reason.

However, perhaps you meant that general principles do no predict specific event. I would have to agree with that. That seems to be the nature of generality - not to be specific. Even the laws of physics as we presently know them do not predict specific events - like my typing these words right now. They are just as much generalities as logic itself.

But Ariels general idea is that the laws of physics doesn't follow from deductive logic, but possibly from inductive reasoning... and I think it's close. Close to the ideas on evolving law in the other thread.

General principles, however, could predict the probability of specific events. Based on principle alone it might be possible to predict how LIKELY specific events might be. Remember that if it is not possible to deterministically say that a specific event has truly happened or not, then it is not possible to count the frequency of occurances and calculate the probablities. So inductive logic comes from deductive logic.

 

[p764rds]

Check Max Tegmarks "Mathematical Universe"
Just equations, and nothing else.

Yes, and those 'equations' implemented in 1s and 0s, data, numbers, - call it what you like. In a Von Neumann-like machine. We are clever enough to design/model a 3d universe prototype (i.e. a bad one) and with quantum computers a better one until eventually... complete the sentence yourself.

 

[Dmitry67]

Yes, and those 'equations' implemented in 1s and 0s, data, numbers, - call it what you like. In a Von Neumann-like machine. We are clever enough to design/model a 3d universe prototype (i.e. a bad one) and with quantum computers a better one until eventually... complete the sentence yourself.

Again, you are trying to find wheels behind the reality.
'Equations' are not 'implemented'. They just exist.
You don't need any Von Neumann machines for the natural numbers to exist. Natural numbers do not require any underlying substance.

 

[p764rds]

Again, you are trying to find wheels behind the reality.
'Equations' are not 'implemented'. They just exist.
You don't need any Von Neumann machines for the natural numbers to exist. Natural numbers do not require any underlying substance.

A particle made of equations? The 'wheels' for that is a Von-Neumann-like machine in 'information space' outside normal 3 space (which itself is a data creation and does not exist in the normal sense we think about).
There are many physicists who already realize that something like this - or similar - is going on, its just that its not in their daily work schedule, so they suppress it - and who is really interested anyway (apart from us geeky folk with weird ideas)?

 

[Dmitry67]

A particle made of equations?

You still not getting the idea.
The reality is not "made of" equations
The reality is a mathematical system, the reality is equations.

Does Mandelbrot's set need a computer constantly calculate it over and over again to exists? Does number 11 become less prime when no computer is verifying that it is really prime in an infinite loop? Mathematical structures just exist, and then don't need any machines to 'calculate' or 'simulate' them.

 

[benk99nenm312]

Yes, and those 'equations' implemented in 1s and 0s, data, numbers, - call it what you like. In a Von Neumann-like machine. We are clever enough to design/model a 3d universe prototype (i.e. a bad one) and with quantum computers a better one until eventually... complete the sentence yourself.

Since this is a free, argumentative thread, I will share my thoughts accordingly.

This is the same thing people have said for a while now. This is a problem with modern physicists. They think in equations, and they neglect what the equations mean. Eventually, they lose the notion of a picture, or a conceptual idea. Numbers are what we use to represent nature. They are not nature itself.

 

[Fra]

I think most sane persons would agree that scientific knowledge doesn't follow deductively from logic.

I see no basis for this statement.

The most sane persons was a provocative stretch, but the I think it should be clear that the scientific method is not a deductive process.

Of course this is an old philosophical problem, the problem of induction. Popper wanted to turn the scientific method into a deductive one, since he thought induction was not valid. Unfortunately he didn't succeed. He ignored the hypothesis generation, which again is a kind of induction.

Though something further classifications appear and it's called abduction, which is a sort of induction where you try to infere the best causal explanation for observer phenomena.

With scientific knowledge isnt' deduced, but rather induced (or abduced) I mean that the inference of laws and general principles from experiemence is a form of a risky argument, it is not a certain argument.

Popper tried to forget about the induction of hypothesis and instead just focues on the falsification, which he first imagined as deductive, either the prediction matches observations, or it doesn't. Then even that is hard due to uncertainty and experimental error, than he agreed to turn into a probabilistic deduction. Which really is a deductive form of induction. But even that makes no sense IMHO because to make a probabilistic dedcution, ie. make deductions rather than inductions, and assign each deduction a probability, you first have to - from experience - infere a probability space! And again, this is not deductive, is risky arguments.

However, perhaps you meant that general principles do no predict specific event. I would have to agree with that. That seems to be the nature of generality - not to be specific. Even the laws of physics as we presently know them do not predict specific events - like my typing these words right now. They are just as much generalities as logic itself.

I mean both. I mean that general principles do not predict specific event. And you then suggest that it still predicts the probability exactly.

Then I have two issues with that.

- To first make a deduction (from general principles), you have to establish the correctness of the general principles. Usually these are inferred from our experience with nature, which again isn't deductive.

- The next problem is exactly what the significance of probability is, when in certain cases it's obvious that it's practically impossible to repeat the experiment, and in particularly to repeat and collect the data an infinite amount of times to get a certain statistics. In that case, what does probabiliy mean? Usually we can think of it in a bayesian sense, but even that leaves issues, unless you pull out of nowhere a master space.

So inductive logic comes from deductive logic.

I was not too careful about my notion, there are different names around here but I was actually talking about induction as a risky reasoning in general.

You seem to talk about induction here as probabilistic deduction. Given the probabilistic formalism, it's true that it's deductive. But the probabilistic general framework isn't given. It contains implicit assumptions and ergodic hypothesis etc. So in the end, it's still not a foolproof and 100% deductive argument - where back to induction.

/Fredrik

 

[Fra]

I think the solution to the problem of induction isn't to focus on wether it's valid, it's to descrie what induction IS, and as I see it it's an evolving process, which evolves by induction, but (uncertain) induction, not deductive probabilistic one, because the probabilistic framework contains implicit information that is only induced, not deduced.

So my original comment was that, I think it should be clear that scientific predictions as well as the inferece of physical law from nature are not riskfree processes, thus not deductive.

/Fredrik

 

[dx]

Fra,

Einstein said in one of his essays, "Physics constitutes a logical system, whose basis cannot be distilled, as it were, from experience by an inductive method, but can only be arrived at by free invention. The justification (truth content) of the system rests in the verification of the derived propositions by sense experiences, whereby the relations of the latter to the former can only be comprehended intuitively."

 

[Demystifier]

As a MUH proponent I can say that:
1. It is know about not being possible to know for certain what machinery behind is right: it is about an absence of any machinery (except formulas).
2. Physics IS mathematics on the fundamental level, so the there is no difference in principle between the mathematics (adequate to our universe) and "what 'really exists'"

But over and over people ask "what is a wavefunction? what is space made of? are virtual particles real?" trying to discover wheels and rubber bands behind the curtain.

I like the way you said it.
But let me explain how I view this from the point of view of different interpretations:

Copenhagen: equations AND observers

Many world: equations AND "frogs" who somehow see only a tiny part of the solutions of these equations

Bohm: equations AND some additional equations (that remove the need for observers and frogs)

MUH: equations AND additional equations AND more additional equations AND more and more additional equations ... until you exhaust the infinite set of all possible equations

In particular, MUH contains Bohm as a special case.

 

[Fra]

Fra,

Einstein said in one of his essays, "Physics constitutes a logical system, whose basis cannot be distilled, as it were, from experience by an inductive method, but can only be arrived at by free invention. The justification (truth content) of the system rests in the verification of the derived propositions by sense experiences, whereby the relations of the latter to the former can only be comprehended intuitively."

This seems like a reasonable way of putting it. However, I suggest that the notion of "free invention" and "intuitive comprehension" can be improved and formalised, as a sort of game of risky reasoning and learning by feedback.

Popper considered that the logic of hypothesis generation belongs to pscyhology of scientists brains, and he didn't seem to think further analysis was relevant. Instead he focused on, given a hypothesis, how can it either be falsified or corroborated.

The scientific problem of induction is based on the general almost unquestionable observation, that science infers laws and general principles from experience interacting with nature. The problem is howto describe this process? Popper thought that the inductive description isn't valid, so he came up with the deductive step of falsification, and dismissed the biggest problem to human pscyhology. Not a very satisfactory resolution.

Still, it's correct that induction such as (we've only seen white swans; therefor "there are no white swans in nature") is not a valid or satisfactory universal abstraction; no one would question that. But there is a more sophisticated way of seeing this inference - like a game. And consensus is emergent among players, in an evolving perspective. This takes on to abstract the very core of the problem that some pople dismiss to "free invention" or "human phsycology". After all the human brain is nothing but a physical system, so I don't see how a scientist can accept to dismiss such a crucial problem to "human mind" and then be satisfied.

The more inductive approach however, and in particular the version I am advocating, suggest that there is a very important feedback between the corroboration/falsification tests and the logic by which new hypothesis is generated. So the ambition is higher than than of Popper. As I see it, we are questioning the PHYSICS and the physical basis of hypothesis generation, which when you think of it, is closely related to the physical basis of expectations and information. Here we are close to QM, which suggest that different observers, having different information, have different expectatins and therefore behave differently!

The deductive focus, focuses on falsification (which is the simplest part). The inductive focus, is on how the hypothesis generator evolves (the deep part). Here comes the evolutionary view, as a possible resolution to the scientific problem of induction: Is this induction valid? Well, what doe valid me? IF it means, is it true, then NO. Instead, this is a game, a game we have no choice but to play.

In this context, the various ideas of evolving law and connecting physical interactions with the "laws of inference" (which are obviously evolving, just like physical law) are interesting.

Part of the key is I think that inference is sujbective, and thus attached to a physical observer. The different observers difference in reasoning upon incomplete information, results in disagreements, which in turn results in physical interactions. So there is an idea how to infere and classify physical interactions and phenomenology from classification evolving interacting learning models.

This a new way of reasoning that also comes with a new abstraction of the scientific method. It can even be said to have the ambition to unify the description of a scientific processes, with a physical processes.

The abstraction and simplification used by Popper is very simplistic. It's not "wrong", it's just
too simlpe, and I think we can get even more enlightened by analyzing the parts that Popper dismissed to self organisation of complex systems such as the human brain.

/Fredrik

 

[Fra]

This isn't to suggest that subatomic particle have "humamn level brains" to reason with. OTOH, what I mean is that the "reasoning" taking place in subatomic physics is pretty much one-2-one with the PHYSICAL processes and interactions that is going on there. This evolving process is the same as the evolving microstructures and how they communicate at this level. This construction would start at the very smallest level, down to the Planck scale or whatever the scale turns out to be.

Like Ariel puts it, mybe the laws of physics governing the interaction of parts of the universe, are simlpy the parts of the universe acting upon incompete information on the others? If that is so, then this route of analysis is likely to bear fruit.

/Fredrik