"Against" Realism [Archive]

Careful

Sep1-06, 05:15 PM

** Patrick Vanesch calls relational QM a form of solipsism, yet there are respected physicists who adopt it. It's just opinion. **

And I agreed with this assesement (actually I made it myself PRIOR to Patrick's intervention), but I also remember from the discussion with f-h that these respected physicists are indeed worried about the lack of synchronisation as they should be. You might want to read what E.T. Jaynes had to say about MWI, he simply said that ``theoretical physics went bezerk''. It is not opinion, an overwhelming majority does not even want to speak about it.

**
My statement that external reality is not an operationally defined concept was intended to suggest that it cannot be meaningfully employed in discussing physics, because there is no objective way to decide which of two definitions is preferrable. **

Rubbish, first of all your operational definition of measurement requires something you cannot capture at all, nobody agrees upon what consciousness is ! In science, you always have to make a definition no matter how you turn or twist the pig. If no such agreement can be made, then you can better close the books and go into politics.

** And that is what I see working in all the hundreds of posts that have been put up here in all the many threads on Bell, locality and interpretation. **

Do you really think that practising scientists care about this ?! :bugeye:
I know of people who think hard about these matters (and that is already not very standard), but none of them would come up with solipsism as it is presented here. 95 percent, in my experience, takes a very pragmatic approach towards this, and with good reason.

** It isn't science, it isn't even well constructed philosophy! **

My god, so you are denying 2000 years of scientific practice ? I am afraid you have been too long amongst ``philosophers'' of science.

By the way if you live by the motto ``on basis of experiments we establish ``truth'' but not on the basis of words of anyone'' well SelfAdjoint, don't forget then that
(a) science is not about the truth, that does not exist. Science is about making a good model of nature in which all factors involved are well defined and fair predictions about the future can be made.
(b) no model should contain any assumption which in principle cannot be falsified by the very instrument of science itself.

Consciouness does not fall under (b), a theory which declares what is real belongs to the material world in principle does.
As I said, you are involved in philsophy of science as we understand it today. The problem with philosophers of science is that they usually do not know the internal dynamics of science where a world view is connected with the boundaries of our understanding. Your philosophy is an unheatlhy extrapolation from the mathematical framework of QM : an extrapolation which shows that any ``believer'' is prepared to acknowledge that he/she did not understand anything about it and is moreover not going to look for anything better ; it is the task of science to take mystery away from things. For example : you are proclaiming the relational point of view (which does contain some serious problems); if you once yourself calculated a solution of Brans Dicke theory or something similar and then imagine the trouble you would have to go through in making such theory a logical theory of relational quantum propositions, to realize in the end that you are stuck with two different notions of time, things like self measuring devices and so on to make your reasoning selfconsistent then I am sure you would pretty quickly pack your bags and try something more realistic to start with.

But again, nothing but philosophical comments, where is the real science ?

Careful

Hurkyl

Sep1-06, 06:08 PM

This is the last thing I say about this unless you have some objections since all this kind of philosophy is turning my stomach.
Well, the problem is that you haven't answered my question at all. :frown: I was trying to translate what you wrote into something more precise, so I could see if what I think you're saying is what you think you're saying.

One could also allow for laws where the value of x now depends on its nearest elements in the future, that would still be a local spacetime theory.
Okay; let's throw in the entire past and future lightcones for simplicity, then discuss particulars when we decide it matters.

Careful

Sep2-06, 12:44 AM

** Well, the problem is that you haven't answered my question at all. :frown: I was trying to translate what you wrote into something more precise, so I could see if what I think you're saying is what you think you're saying. **

:uhh: I *literally* said that your definition of local realism is *fine*, although some alterations could be made (such as taking into account some part of the future), so that makes one wonder why you consider this as no answer at all. Your definition was in no sense more precise (!), you keep on confusing writing clear ideas in a mathematical language as a significant contribution. What I just said, you can all find in Franco Selleri ``The EPR paradox'' chapter 5 : proposed solutions (although he would call holographic solutions ``non local'', better would be apparently non local). In contrast to what some think, rigorous definitions of local realism *have* been made long time ago... Clearly adding some part of the future helps, since then Bob can send a signal to the future of Alice with the result of his measurement and vice versa, but that would be non local, but causal. Some holographic principle is clearly local and solves the issue, it is just that events which are far away on the ``base manifold'' can be arbitrary close together in the extra conal dimension (actually this idea is ``cleaner'' than the wormhole suggestion since you have no problems whatsoever here with defining a global arrow of time), etc... Now, you might want to read this chapter prior to making any further comments on what I said, which is the respectable thing to do. In contrast to some, I am not going to say after you read this, that you might be drawing your conclusions on a paper uttering some simple ideas since at least the physical context is very clear in this book (which should be studied by anyone in that field in my opinion) - Selleri is a first class scientist. EDIT : it needs to be said that the idea of negative probabilities would deserve more attention, a good survey paper on this is ``A review of extended probabilities'' Physical reports, 133, No 6 (1986), pages 337-401.

Careful

RandallB

Sep2-06, 11:58 AM

(a) science is not about the truth, that does not exist. Science is about making a good model of nature in which all factors involved are well defined and fair predictions about the future can be made.
(b) no model should contain any assumption which in principle cannot be falsified by the very instrument of science itself.

Consciouness does not fall under (b), a theory which declares what is real belongs to the material world in principle does.I like these; concise and to the point, descriptions.
Do they come from the Selleri (and Afriat) book “The Einstein, Podolsky, and Rosen paradox” you mentioned.
Or do you have another source for them – I ‘d like to read the whole of the ideas around them.

Careful

Sep2-06, 12:15 PM

I like these; concise and to the point, descriptions.
Do they come from the Selleri (and Afriat) book “The Einstein, Podolsky, and Rosen paradox” you mentioned.
Or do you have another source for them – I ‘d like to read the whole of the ideas around them.
No, they come from me, it is in my blood (and I am dead serious about it) :rolleyes: But if you insist, the introduction of the latter book contains some spicy remarks about the sociology of science. However, I all find this a bit sad, you know ... (a) first people say ``you cannot violate the Bell inequalities´´ then (b) when you point out it can be done, it is against their religion. The book of Selleri and Afriat is a true masterpiece of objectivity in science (and very informative as well), he is even slightly critical towards other well known realists. It contains as I seem to remember also a section about *single event* interpretations of the Heisenberg principle and a brief summary of proposed tests to violate it. I would recommend anyone interested in physics to buy it, even if it were just to broaden your horizon and to remain open to the possibility that local realism (or something close to it, like the value of a field in one spacetime point being determined by the field content in some finite part of the future and past lightcones) can return.

However, it does not contain any full solution to the paradox which is satisfactory *in my mind* and which has been shown to reproduce all QM effects (although one can be hopeful). Merely it outlines and explains well the ideas behind the different proposals for the solution of the latter and provides enough useful references.

Careful

Rade

Sep2-06, 01:20 PM

...What does realism mean to you?...Reality is that which exists. How humans know it or not is another matter--IMO.

simon009988

Sep2-06, 01:44 PM

1. What does realism mean to you?
Realisim to me is what your mind percieves.

2. Einstein said: "I think that a particle must have a separate reality independent of the measurements. That is: an electron has spin, location and so forth even when it is not being measured. I like to think that the moon is there even if I am not looking at it." Is this realism?

This is pure supernatural and cannot be measured in any way, therefore not reality.

Careful

Sep2-06, 02:36 PM

** 1. What does realism mean to you?
Realisim to me is what your mind percieves. **

So, what is your mind and what is perception ? By what mechanism does your mind operate ?

**
2. Einstein said: "I think that a particle must have a separate reality independent of the measurements. That is: an electron has spin, location and so forth even when it is not being measured. I like to think that the moon is there even if I am not looking at it." Is this realism? **

This is a form of realism.

** This is pure supernatural and cannot be measured in any way, therefore not reality. **

Sure it can be measured, but not in the way you imagine measurement.
So, your mind measures your mind he and stones, ants and so on have this precious commodity too. Basically, it occurs to me you are denying the practise of physics. How was an electron observed ? By following the presumed track in a bubble chamber one says ``this track was formed by the electron which passed here´´. So, one assumes the electron passed there even if no one had seen it ! We speak about particles, since pictures coming from scattering experiments suggest us such interpretation because we see something *was* there prior to our minds measuring circumstantial evidence for it.

Careful

Hurkyl

Sep3-06, 10:26 PM

Careful,

You can't communicate very well unless the person speaking and the person listening both think the same thing was said. It happens often that two people will see the exact same words and come away with entirely different opinions about what they said.
I *literally* said that your definition of local realism is *fine*
For example, after reading this, I would have expected there to be, in your original post, a phrase that resembled "your definition of local realism is fine"... or at the very least, expected to see the word "fine".
writing clear ideas
The clarity of an idea is, of course, a subjective notion. And even if the idea is clear, the writing of the idea may not. After all, "yes" is rather clear, yet you managed to write five long sentences in post #5 without managing to convey it to me.

And the converse is true...
you keep on confusing writing clear ideas in a mathematical language as a significant contribution.
...
making any further comments on what I said
...
you might be drawing your conclusions
I was simply trying to figure out what you were saying, while trying very carefully not to "make comments" or to "draw conclusions" -- and making a "significant contribution" was the furthest thing from my mind. But, I did not manage to convey that to you.

I translated into the "mathematical language" because, IMHO, there's less "wiggle room" for conflicting interpretations -- and also because it's a generally more objective language. If we can agree on a mathematical translation, then I would have high confidence that what I think you said matches what you think you said.

But if you would rather be misinterpreted... then you can't complain when it happens. :wink:

Careful

Sep4-06, 12:51 AM

***
I translated into the "mathematical language" because, IMHO, there's less "wiggle room" for conflicting interpretations -- and also because it's a generally more objective language. If we can agree on a mathematical translation, then I would have high confidence that what I think you said matches what you think you said.

But if you would rather be misinterpreted... then you can't complain when it happens. :wink: **

Thanks for clearing that out - I will simply add references each time I make an apparantly ``strange'' statement. The reason why I gave you a broader answer in my first reply is because local realism (and physics in general) is not something static for me. If I restrict myself to your more or less traditional specification then I am cornered into the four options I mentioned (or you can also declare the measurement loophole to be fundamental); on the other hand, there has always been this interesting possibility of using advanced Green functions ... What I want to tell you is that physics consists of having mechanisms in your mind, imagining yourself how stuff works ; since quantum mechanics makes this difficult for you, the first thing to do is to clear out the latter. I have never been ``pro string theory'' but self Adjoint recently mentioned that he thought to have heard that within ST a non supersymmetric fermi model had been constructed, now that would be interesting physics. We still don't understand yet our first elementary particle (electron models are a recurrent theme in the literature - especially in the 70 ties and 80 ties, some considerable effort was put into that).

Careful

vanesch

Sep4-06, 02:59 AM

By the way if you live by the motto ``on basis of experiments we establish ``truth'' but not on the basis of words of anyone'' well SelfAdjoint, don't forget then that
(a) science is not about the truth, that does not exist. Science is about making a good model of nature in which all factors involved are well defined and fair predictions about the future can be made.
(b) no model should contain any assumption which in principle cannot be falsified by the very instrument of science itself.

In as much as (a) is a very profound statement, you should apply it entirely logically until the end. I agree with (a), with maybe one small modification: I'm not even sure we can say that "truth doesn't exist", only, that "truth isn't accessible", and we leave in the middle whether truth exists or not. We simply know with certainty that we won't know it with certainty. The realisation of this philosophically elementary fact does - IMO - a lot of good to any of these sometimes heated discussions :cool:

And in fact it is entirely the point I'm often making: don't think that what we scientifically "knew" 400 years ago, today, or 400 years from now, has much to do with "truth". It is all about, as stated, making a model of observational data. However, in as much as this model has some logical consistency, it also has its *Platonic*, conceptual existance. As such, I don't agree at all with (b), which I find a totally arbitrary requirement. The only goal of the model is to make a model of observational data. What elements are used to set up such a model is entirely free, I'd say. Of course there can be *preferences* and Occam's rasor is a good guide: two models which are empirically equivalent, but one which has some extra elements which the other doesn't need, might be preferentially rejected in favor of the "simpler" one. But again, this is just a guiding principle, not a strict requirement.

Given that we have no access to "truth", but only to observational data, the best we can ever do is to think up (one or several) models which can explain these observational data. It would be nice too, if these models were logically consistent. But as to what a model should contain, and not, is, IMO, purely a matter of taste. It needs to work, it needs to make correct empirical predictions, it needs to be logically consistent and that's it.

As was pointed out (and as is philosophically also known) is that solipsism is irrefutable (but also not very productive as a starting point). That means that whatever you take as "reality", it is a hypothesis, and nothing more. You can never *prove* any reality, so it is always a hypothesis.
So with the word "reality" always comes a hypothesis.

As to 1.) What does realism mean to me
Looks like Naive would describe me best.

This is correct: the "realism" one is talking about here is what's philosophically called "naive realism" (but without any pejorative meaning to "naive"). It simply means that the hypothesis of reality assumed, is that what constitutes "reality" is nothing else but what is observed.
For a long time, physicists have taken this hypothesis, even without saying so ; it is only since Faraday and his "field lines" that people started talking about "things that might be real but not directly a product of our observation", and hence, a modest departure from naive realism.
It is my understanding that the word "realism" in the context of Bell/EPR/local "realists" etc... is this: a version of naive realism which ultimately makes the hypothesis that observation is what is "real".

Another possible hypothesis of reality (let's not forget that in any case it is a hypothesis), is a version of idealism. That is, we picture reality as a part of the Platonic world of abstract ideas. Observations are then nothing else but specific derivations, through "glasses", from this view. I think personally that this is the most fruitful working frame for a physicist - always keeping in mind that it is entirely hypothetical.
So what should now be taken as this "reality" in this hypothesis ? Well, nothing else but the model which gave us the logically consistent agreements with observation we started with.

Within this frame of thinking, it is of course totally unsound to declare "certain elements of the model agreeing with elements of reality", because we declared, by hypothesis, our model to BE reality. I often called that the "toy world of the theory". It is in this mindset, btw, that I defend MWI as the "correct" interpretation of quantum theory - simply because it assigns reality to the elements of the model (= quantum formalism). Within this frame of thinking, also, MWI is "locally realistic", simply because the dynamical prescriptions have some form of locality to them, for a suitable definition of locality. As an idealism, it is true that MWI is rather remote from any naive realism, which invites all the agressivity towards it by people who assume implicitly naive realism. But this comes about because the initial "hypothesis of reality" was totally different in both cases. So the entire conflict comes about when this idealism is confused with (implicitly assumed) naive realism. It is in this context that the "naive" in naive realism becomes pejorative: its proponents don't realise they already made an implicit hypothesis about what is "real" (while acknowledging also that one can't know this for sure at the same time).

And as we all seem to agree upon the fact that we'll never know what is "true", this discussion can go on for ages without ever finding any resolution.

Careful

Sep4-06, 03:11 AM

** In as much as (a) is a very profound statement, you should apply it entirely logically until the end. I agree with (a), with maybe one small modification: I'm not even sure we can say that "truth doesn't exist", only, that "truth isn't accessible", and we leave in the middle whether truth exists or not. We simply know with certainty that we won't know it with certainty. The realisation of this philosophically elementary fact does - IMO - a lot of good to any of these sometimes heated discussions :cool: **

:rofl: Knitpicker :rofl: I think there exists a reality (we need some form of reality when we make theories), but that indeed we will never know that the ansatz we make about it is true or not. In a pragmatic sense the truth does not exist, since we will never know that we are right even when we are.

**
As such, I don't agree at all with (b), which I find a totally arbitrary requirement. The only goal of the model is to make a model of observational data. What elements are used to set up such a model is entirely free, I'd say. Of course there can be *preferences* and Occam's rasor is a good guide: two models which are empirically equivalent, but one which has some extra elements which the other doesn't need, might be preferentially rejected in favor of the "simpler" one. But again, this is just a guiding principle, not a strict requirement. **

So I guess you have to live with the problem of my hundred eyes in Japan and China as I mentioned in a previous post on this thread. Or you have to anwer my previous objection about how your belief does not contradict the practise of science: I am not speaking about the freedom we have in cooking up the model, but how the model deals with our ability to produce it.

** Within this frame of thinking, it is of course totally unsound to declare "certain elements of the model agreeing with elements of reality", because we declared, by hypothesis, our model to BE reality. ***

So, how would you discover the electron or anything which is NOT in your model ? I mean, you would have to avoid the argument, the electron (positron) was discovered because we observed its track through the nebula.

Careful

vanesch

Sep4-06, 05:51 AM

So I guess you have to live with the problem of my hundred eyes in Japan and China as I mentioned in a previous post on this thread. Or you have to anwer my previous objection about how your belief does not contradict the practise of science: I am not speaking about the freedom we have in cooking up the model, but how the model deals with our ability to produce it.

I agree with your objection about the eyes in China (and for our Chinese membership: the eyes in New York :redface: ), and the fundamental objection I also have with equating *your* observations with reality while denying any "reality out there" by hypothesis. So I go for your second option: the model should indeed be such that within it, an observer should be able to reproduce it (as he obviously was trying to do).
I put that on the slide of "self-consistency" of the model, and "agreement with observation". I think the entire endeavour of MWI people is to try to do exactly that: find A (even if it is totally "bezerk") self-consistent way of deducing how an entity within the model would arrive at those observations and conclusions, as one actually did (in this case, write down the rules of the quantum formalism).

I agree that this is one of the stronger arguments for naive realism: the relationship between observation and reality being by definition (close to) 1-1, this step is evident, while it isn't in an idealist view. Nevertheless, the opposite is, IMO, not *necessary* (even though - I admit - attractive): it is sufficient to have such a self-consistent view (no matter how bezerk), for the idealist, to be satisfied.

So, how would you discover the electron or anything which is NOT in your model ? I mean, you would have to avoid the argument, the electron (positron) was observed because we discovered its track through the nebula.

Elementary, dear Watson :tongue2:

From an idealist view, you cannot "discover" an electron. You can only make observations, and then ponder about it, and come up with a MODEL (as you said yourself), which might then predict said observations.
The model is then "a charged particle which produces tracks in a cloud chamber and which I decide to call 'positron' ".
Once this model gets accepted/integrated/gets other observational successes, in the idealist viewpoint, it then becomes (by convention/hypothesis/majority vote...) an element of reality.

It is the success of the "model of the electron" which turns it into something we call "real".

So, in short, you cannot discover anything. You can only make observations, and think up models of those observations. This successful tandem is then the "discovery" of the entity of your new model, if it turns out to be successful/useful/socially accepted. At least according to the idealist viewpoint.

But of course the closer an observation is to our biological senses, the more intuitive this model becomes ("that's my mom") and from a certain point on, our sense of reality for certain models becomes so overwhelming that questioning this "everyday" reality triggers unfriendly statements about the mental health of the one making those questioning statements o:) . In other words, for everyday observations, we strongly intuitively tend to take on the naive realism viewpoint. The question is whether this intuition is really so fundamental. It is the fundamental objection to an idealist hypothesis.

Careful

Sep4-06, 06:48 AM

**
Elementary, dear Watson :tongue2: **

Not quite :biggrin:

**
From an idealist view, you cannot "discover" an electron. You can only make observations, and then ponder about it, and come up with a MODEL (as you said yourself), which might then predict said observations. **

Hmmm, I always had the strange idea that from time to time we discover something in our life :rofl:. But when constructing such model, you always use classical reasoning, you assume something was there which did this and that to the nebula which you do observe now. Whether you have acces to this reality or not is some other matter, and what you could measure would probably be some emergent phenomenon and not the ``real'' stuff (even within the theory you construct). Even in quantum mechanics, you can easily uphold the view that at any time the electron is somewhere on the support of its wave function (which would be the track in the nebula), but you simply don't know where.

**But of course the closer an observation is to our biological senses, the more intuitive this model becomes ("that's my mom") and from a certain point on, our sense of reality for certain models becomes so overwhelming that questioning this "everyday" reality triggers unfriendly statements about the mental health of the one making those questioning statements o:) . In other words, for everyday observations, we strongly intuitively tend to take on the naive realism viewpoint. The question is whether this intuition is really so fundamental. It is the fundamental objection to an idealist hypothesis. ***

Ok, so let me ask you this : if quantum theory could be explained in an entirely ``realistic'' way (which it can, by holography (seems very plausibe), the future influencing the present (requires much more work) and so on...) why uphold this ``idealist'' view ? It is not that these two models are in accordance with my intuition, nobody likes to accept a shadowworld beyond ones perceptions, but at least one is able to clearly define it, make the math much easier (a local model in a slightly more complex shadow world is still much more economic that the configuration space methods in QM) and well defined ! I mean, strictly speaking, I cannot close the door for your viewpoint (and basically, I don't care :wink:) but it is a very difficult and unnatural position to maintain as I see it.

Careful

vanesch

Sep4-06, 07:18 AM

But when constructing such model, you always use classical reasoning, you assume something was there which did this and that to the nebula which you do observe now. Whether you have acces to this reality or not is some other matter, and what you could measure would probably be some emergent phenomenon and not the ``real'' stuff (even within the theory you construct). Even in quantum mechanics, you can easily uphold the view that at any time the electron is somewhere on the support of its wave function (which would be the track in the nebula), but you simply don't know where.

Well, a quantum theory = a "classical" theory + superposition principle, or in other words, what we call "classical" is a basis. If we now have some arguments which make us understand (or make us hope one day we might know) why our *observations* often agree with basis-states (in other words, are classically-looking), then this "classical reasoning" is not so wrong at all. When you do that, you are implicitly reasoning in terms of basis functions, and not in terms of the entire state space, but that doesn't matter. When you say "the electron is somewhere", then this is a shortcut for "I use as a basis, states which I call 'the electron is there', and I will probably observe also states close to 'the electron is here' ", but of course the superposition principle mixes into this which first makes superpositions of the different states, and then also is supposed to explain why my observations are again limited to the one of those states.

So "classical reasoning" is entirely allowed for. It just changed meaning, and became "reasoning in a basis related to observation".

Ok, so let me ask you this : if quantum theory could be explained in an entirely ``realistic'' way (which it can, by holography (seems very plausibe), the future influencing the present (requires much more work) and so on...) why uphold this ``idealist'' view ?

Because it is just another idealist view ! It is not part of naive realism to say that the future determines the present, not any more than parallel worlds are. Simply because our experienced "flow of causality" is just as well part of our observational sense of reality as is anything else, and as such, cannot consider "the future determines the past". I'd say it is just a matter of taste to say what you like more.

Now, in as much as this is technically possible (isn't this the "transactional interpretation of QM" in some way, although I thought it had serious problems for multi-particle correlations - so I'm not well versed in all this), it is just a model amongst others. You should know very well that I'm very favorable of making alternative models.

It is not that these two models are in accordance with my intuition, nobody likes to accept a shadowworld beyond ones perceptions, but at least one is able to clearly define it, make the math much easier (a local model in a slightly more complex shadow world is still much more economic that the configuration space methods in QM) and well defined ! I mean, strictly speaking, I cannot close the door for your viewpoint (and basically, I don't care :wink:) but it is a very difficult and unnatural position to maintain as I see it.

Well, to me they are certainly on the same levels of "bezerkness" and I don't think there's a reason to prefer one over the other, unless one formalism is mathematically much more appealing than another. If some equivalence is established, then it is entirely a matter of taste (and probably of social convention). I think it is then very interesting to look at both models. If equivalence is not established, then this is also a very interesting situation of competing models.

But all this doesn't do away with the fact that the idealist interpretation of the standard quantum formalism still smells more like MWI, and that this other formulation will have its own, different idealist interpretation, given that it will be formally different (though possibly equivalent).

Again, given that this is all matter of hypothesis, I don't see why one should fight over it, or adhere to one over the other. The more different views one is aware of, the more understanding one usually gains of the matter at hand.

This is why I don't fight (intelligent) local realists, nor do I "adhere" to any such vision. It's just interesting to know about, that's all.

Careful

Sep4-06, 07:44 AM

** Well, a quantum theory = a "classical" theory + superposition principle, or in other words, what we call "classical" is a basis. **

That remains to be seen, as soon as one includes self interactions, it occurs to me that the superposition principle *might* go down the drain if one insists upon the theory to be well defined. Check out one of the latest papers of Thomas Elze on this (if you want to, I will look it up) where you have only a weak form of the superposition principle.

** If we now have some arguments which make us understand (or make us hope one day we might know) why our *observations* often agree with basis-states (in other words, are classically-looking), then this "classical reasoning" is not so wrong at all. When you do that, you are implicitly reasoning in terms of basis functions, and not in terms of the entire state space, but that doesn't matter. When you say "the electron is somewhere", then this is a shortcut for "I use as a basis, states which I call 'the electron is there', and I will probably observe also states close to 'the electron is here' ", but of course the superposition principle mixes into this which first makes superpositions of the different states, and then also is supposed to explain why my observations are again limited to the one of those states. ***

Nonlinearity is the key word I presume, a *dynamical* law of observation should break the superposition principle.

** Because it is just another idealist view ! It is not part of naive realism to say that the future determines the present, not any more than parallel worlds are. **

Well, not quite :wink:, first of all observations are still REAL in such world, if Careful sees a dead cat, Vanesch will too, I have no synchronisation difficulties. I have already long time said that if you want to predict the ideal quantum correlations using a local theory, then you will have to redefine what is real. But still, what is real, does not depend upon my perception, on the contrary, the reality will explain perception itself.

**Simply because our experienced "flow of causality" is just as well part of our observational sense of reality as is anything else, and as such, cannot consider "the future determines the past". I'd say it is just a matter of taste to say what you like more. **

Well, I would think the experience of the flow of causality to remain the same for heavy stuff (see my response on the other thread).

** You should know very well that I'm very favorable of making alternative models. **

Of course, this is just a friendly conversation. :smile:

**Well, to me they are certainly on the same levels of "bezerkness" and I don't think there's a reason to prefer one over the other, unless one formalism is mathematically much more appealing than another. If some equivalence is established, then it is entirely a matter of taste (and probably of social convention). I think it is then very interesting to look at both models. If equivalence is not established, then this is also a very interesting situation of competing models.**

Well you probably know this paper, but wait ... perhaps not (it contains some important arguments) : ``Simulating physics with computers´´, Richard.P. Feynman, International Journal of Theoretical Physics, Vol 21, Nos 6/7 1982

** Again, given that this is all matter of hypothesis, I don't see why one should fight over it, or adhere to one over the other. The more different views one is aware of, the more understanding one usually gains of the matter at hand. **

Indeed, no fight is necessary !

Careful

setAI

Sep4-06, 01:43 PM

the problem is that a century later- even smart people have trouble accepting the implications of unitary QM- that is the less that an element of a system is observed- that is causally connected to an observer- the more it is in a superpostional state of ALL possibilities-and this does extend to all scales- it is just too complicated and EXPENSIVE at present to measure those affects with mezzo scale and larger systems- what we call reality is a sum-over-histories of what we are interacting with NOW yet the complexity of our interaction with the environment severly probabilistically limits the possibilites to what appears to be a singular reality and a single past- except at the edges of shadows- as David Deutsch put it

selfAdjoint

Sep4-06, 03:58 PM

That remains to be seen, as soon as one includes self interactions, it occurs to me that the superposition principle *might* go down the drain if one insists upon the theory to be well defined. Check out one of the latest papers of Thomas Elze on this (if you want to, I will look it up) where you have only a weak form of the superposition principle.

Have you loked into the behavior of solitons? They are a characteristic behavior of nonlinear equations; e.g. it has long been known that the "inverse problem" of identifying a potential in a one-dimensional Schroedinger equation from its scattering behavior leads to Kottweg-DeVries (KdV) nonlinear ODE with soliton solutions.

And they obey a kind of quasi-superposition behavior, so you could have superposition where it counts without assuming it to be some kind of universal ordering principle.

Careful

Sep5-06, 12:11 AM

** Have you loked into the behavior of solitons? **

Yes

** They are a characteristic behavior of nonlinear equations; e.g. it has long been known that the "inverse problem" of identifying a potential in a one-dimensional Schroedinger equation from its scattering behavior leads to Kottweg-DeVries (KdV) nonlinear ODE with soliton solutions. **

Right

**
And they obey a kind of quasi-superposition behavior, so you could have superposition where it counts without assuming it to be some kind of universal ordering principle. ***

Correct, if you have two bubbles with more or less disjoint support (that is A is very weak where B is very strong), then this automatically leads to that. But the key message here is that the AND automatically becomes an OR, there is almost no interference between the different solitons (so for example a superpostion of two disjoint soliton beams can be seen as just two different beams). In Barut self field for example one can take soliton like solutions for the single events, they behave like particles but still contain the interference information due to the solution of the linear equation - so there is no measurement problem here (actually this only works for fermions). In GRW for example, the unitarity is broken due to the introduction of stochastic noise. When I speak about a non linear extension of the Schrodinger equation, I do not mean to intend that the statistics of the particles (obviously such a psi has no good probability interpretation) is not going to satisfy a unitary evolution law (something which is a very delicate issue, vis a vis black holes), but that the hidden theory which includes single events is necessarily non linear and much more involved (remember, Vanesch and I were talking about the measurement problem) - there can be information loss at the classical level though. The quantization of gauge fields is a very different issue (and might not be necessary at all).

Careful

Careful

Sep5-06, 12:33 AM

**the problem is that a century later- even smart people have trouble accepting the implications of unitary QM- that is the less that an element of a system is observed- that is causally connected to an observer- the more it is in a superpostional state of ALL possibilities-and this does extend to all scales- it is just too complicated and EXPENSIVE at present to measure those affects with mezzo scale and larger systems- what we call reality is a sum-over-histories of what we are interacting with NOW yet the complexity of our interaction with the environment severly probabilistically limits the possibilites to what appears to be a singular reality and a single past- except at the edges of shadows- as David Deutsch put it ***

Yes and it was for sure problematic that one Einstein could not accept absolute thinking after 250 years of Newtonian bucket dominance. Moroever, I do not have problems accepting the Schrodinger wave at all, I reject the measurement postulate though.

Careful

vanesch

Sep5-06, 12:56 AM

** Well, a quantum theory = a "classical" theory + superposition principle, or in other words, what we call "classical" is a basis. **

That remains to be seen, as soon as one includes self interactions, it occurs to me that the superposition principle *might* go down the drain if one insists upon the theory to be well defined.

Ok, but then it is not "quantum theory" but another theory. In quantum theory, as far as I know, the strict superposition principle is postulated to hold. If you change that, you have another theory, which may be superior, and we'll then refer to quantum theory as its linear predecessor. If strict linearity leads to inconsistencies, then that only means that quantum theory is inconsistent - but it might be that it is only the quantum field model that might suffer from that, not quantum theory in all generality (for instance with just a finite number of degrees of freedom).

Check out one of the latest papers of Thomas Elze on this (if you want to, I will look it up) where you have only a weak form of the superposition principle.

Pffft... guess I have to say "thank you" for the reference. If I would read all the stuff that is suggested to me, I would spend even less time doing useful stuff :biggrin:

Nonlinearity is the key word I presume, a *dynamical* law of observation should break the superposition principle.

But then it is, strictly speaking, not a standard quantum theory where this superposition is to be strictly valid, no ? But rather a successor.

Well, not quite :wink:, first of all observations are still REAL in such world, if Careful sees a dead cat, Vanesch will too, I have no synchronisation difficulties.
I have already long time said that if you want to predict the ideal quantum correlations using a local theory, then you will have to redefine what is real. But still, what is real, does not depend upon my perception, on the contrary, the reality will explain perception itself.

Yes, granted. But so does "a bag of events" (which you sometimes call superdeterminism). We're back to 'correlations happen', and now they come in from the future instead of from some specific initial condition in the past.

What you probably want to say, is that in such a situation, you do not have to delve into the very painful question of exactly what constitutes "an observer", because there are still perfectly well defined events (which do not exist independent of a "branch choice" in an MWI view). Granted. You're relieved from considering this question for the definition of "events". The question is if that's a necessary requirement. Again, it can be advantageous not to have to delve into this. But as, philosophically speaking, sooner or later, you have to confront the question of what exactly is a subjective experience and how it is related to the physical world/model/theory (the famous psycho-physical parallellism von Neumann already realised was the crux in understanding QM), you only bought yourself some time by requiring a physical theory to be clear of these considerations.

So I can understand the desire to uncouple this question from "physics per se", but in my opinion, it is not more than that: something that is to be desired. It's not a hard requirement.

All the ponderings about QM opened this Pandora's box of bringing in conscious/subjective experience into a full physical theory, and once you consider it, it is hard to find a fundamental reason to put it back in the box and reject the idea on some fundamental ground. Sure, things would be cleaner if this messy problem were uncoupled from "physics", but I don't see why we can require this as an absolute requirement, especially because it doesn't fundamentally solve anything about the question of what *is* a subjective experience. It only allows you to ignore the question, not to answer it.

Careful

Sep5-06, 01:13 AM

**Ok, but then it is not "quantum theory" but another theory. In quantum theory, as far as I know, the strict superposition principle is postulated to hold. If you change that, you have another theory, which may be superior, and we'll then refer to quantum theory as its linear predecessor. If strict linearity leads to inconsistencies, then that only means that quantum theory is inconsistent - but it might be that it is only the quantum field model that might suffer from that, not quantum theory in all generality (for instance with just a finite number of degrees of freedom). **

Three remarks here
(a) no not necessarily: the non linearity works at the level of the single events, not at the level of the statistics per se (I still have superposition there). Quantum theory has no decent account of single events (Schrodinger + collapse ``='' non linear). Something similar goes in BM, the point particles satisfy a non linear ODE in configuration space, but still the statistics is just unitary (the differential equation for the Wigner density is of the Liouville type). Of course I do not believe in point particles, neither in action at a distance ...
(b) Quantum field theory needs an infinite number of degrees of freedom, otherwise no scattering.
(c) Another interpretation would be that at the level of the statistics the Schrodinger equation would be non linear, meaning that you would build in some kind of irreversibility in the dynamics of the latter. I guess you could say that the latter implies some inherent information loss in nature (black holes ?) at the level of the statistics. But I see no need for that ...
My original remark that ``interactions might make QFT non linear'' was intended to mean that a consistent theory of QFT could be written as a ``single particle'' non linear field equation. There is a beautiful book by Karel Kowalski (which I unfortunately could not read yet entirely) ``Methods of Hilbert spaces in the theory of nonlinear dynamical systems´´ which explicitates this. Barut's self field can be seen in a two ways : (a) as a self interacting soliton (one particle), or (b) by solving the equation by iteration, starting from a general solution to the linear one, one can see the higher order correction terms as encoding the multiparticle scattering amplitudes.

**
Pffft... guess I have to say "thank you" for the reference. If I would read all the stuff that is suggested to me, I would spend even less time doing useful stuff :biggrin: **

I give good stuff :biggrin:

***All the ponderings about QM opened this Pandora's box of bringing in conscious/subjective experience into a full physical theory, and once you consider it, it is hard to find a fundamental reason to put it back in the box and reject the idea on some fundamental ground. Sure, things would be cleaner if this messy problem were uncoupled from "physics", but I don't see why we can require this as an absolute requirement, especially because it doesn't fundamentally solve anything about the question of what *is* a subjective experience. It only allows you to ignore the question, not to answer it. ***

I do not agree here, as materialist I would simply say that subjective experience is the result of biophysical processes. What is ``subjective experience´´ anyway ?

Chaos' lil bro Order

Sep5-06, 02:03 AM

This seems like philosophy and not physics to me but 'realism' or 'reality' are very easy to define in my mind. Reality is independent of observation in the strictest sense, but to humans, we must accept our 'personal' reality as a collection of sensory inputs to which we give meaning to, and draw meaning from. That which is beyond our 5 senses is unknown and cannot be known, period. Barring the emergence of a 6th sense, we are confined to enhancing our 5 senses with the aid of technologically-enabled sensory multipliers such as telescopes, microscopes, voltmeters and microphones, etc. But even these devices that empower our senses with more and more accurate means by which to measure more and more minute amplitudes of physical phenomona, serve only to define reality in a manner that we are hardwired to grasp. Our only possible perspective of the reality of the universe is neccesarily that with which our senses are so kind as to furnish us with. Yet, I still believe that there are fundamental properties of the universe that are consistent in all regions of space.
As a reductionist I find myself thinking that all matter, anti-matter and radiation consists of particles at a sufficiently small scale. In fact, there is no reason to believe that one day we won't split a photon into even smaller fragment consituents, or even split the quantum field and strings into even tinier pieces. Furthermore, we cannot know if there is an upper limit to the size of our universe or if you believe so, our multiverse. Many people picture themselves in the middle of the known magnitudes of scale ruler... we are much bigger than quarks and much smaller than the universe. But for all we know, our observable universe is the limit of 'reality's' size and the quark can be split into pieces 10*trillion times smaller than it is, so really we are giants in the entire schemata of reality, in fact even ants are.
My main point of this idea of what 'true' 'reality' is, is that all conversations wishing to seek truth, should stay within the confines of our senses and the perceptions we create from these curriers of 'reality's' data.

AnssiH

Sep5-06, 04:56 AM

Philosophy, sweet :)

1. What does realism mean to you?

I'm a strict materialist, so it means that there is a world out there, which is also the cause of conscious experience. In fuzzy language; Conscious experience is what happens when physical organism starts using such method of prediction that it builds a semantical worldview (=self-supporting, not representing "the truth", but merely "a way to comprehend") out of classifying the patterns it observers into "sensible objects" (with mere "assumptions") until it knows enough about the behaviour of such objects to be able predictions of systems become possible. One arbitrary assumption in such worldview is the assumption that there exists one's "self".

This is literally a hypothesis about the phenomenon of conscious experience existing on the basis of physical things (brains/neurons) expressing by their spatial/temporal form, an artificial model of the "world" around the organism, for the purpose of being able to predict things. We are not conscious of the world around us, but merely of this semantical model.

Consciousness is a side-product of the brain building such a worldview where certain the assumption about "self" has formed, and thus the surrounding world is interpreted in the form "this and that happened to me". The experience of free-will is what only exists in our semantical comprehension of the world, while in fact all our decisions are based directly or indirectly to the outside pressures (things we've learned, and how we interpret the situations according to things we've learned).

Simply put, we make our decisions mechanically based on the cumulated knowledge of our experiences, but we have a conscious experience of our self "searching for" the correct decisions from our worldview (thinking), as if there is a fundamental "self" with free will making choices (well, pretty simple philosophical excercises already show that free-will is a non-sensical thing at a conceptual level already, plus many experiments show that no, we are not aware of having made a decision when the physical state of the brain already reveals the choice has been made. This should not be a surprise to anyone dabbling in materialistic philosophy)

This view also explain why there exists such philosophies as idealism or dualism or anything of that kind. No, it does not prove them wrong, it just explains why there are different ways to see same things, and it explains great many things about our behaviour and about our observations in general.

So we could say that being a materialist is to an extent an arbitrary choice. Why I'm not considering idealism then? Because it tends to lead either a solipsism, or to the idea that some kind of god is "feeding us with our ideas". And also many experiments as judged with a materialistic view say a lot about how our "ideas" exist physically, and with that knowledge it is just too naive to think that "ideas" are fundamental. Simply put, these philosophies make assertions about some very very very complex behaviours being actually fundamental (like the sentient behaviour of god)

And why would anyone believing in solipsism try to convince anyone else that world is solipsistic? HELLO??!

Why I'm not considering dualism, is because it too makes certain assumptions about fundamentals that become apparently naive very quickly.

Why I'm not considering panpsychism; because it's just too damn stupid :) It revolves around unbelievably moronic ideas about what are objects metaphysically. Human brain is not a metaphysical object my friends, nor is your car! This view is completely inconsistent and full of self-contradiction.

So in my view, our understanding of reality is based on making arbitrary assumptions about it until we have a coherent picture for making predictions. Any behaviour is a case of prediction. ANY. Walking, talking, inventing, thinking... Our understanding of anything is literally a case of some pattern being classified into such and such concept that we assume to behaves in such and such ways due to past experiences or assumptions about combinations of concepts, and because of this it is also apparent that no worldview is "correct" or "true" to reality, but merely a method of comprehending it. This is why we can look at any system and understand it in a number of different ways.

This also means that ANY form of realism is to an extent naive realism. Even mine, as it also is based on semantical concepts. We are always forced to make arbitrary assumptions about things that "are fundamentally real", while not even this very classification of reality into sensible objects is in any way "correct" way to see the world, yet it is the ONLY way we can comprehend anything.

One simple thought exercise that reveals a little bit of the problem; look at any shadow around you. Looked? Now look at it again. Ask yourself, is it still the "same" shadow as it was before? No? Yes? What about the shadow of a building in two different days?

No, we should not interpret reality as if shadows have identity. It is just a stable pattern. We should not imply ANYTHING to have identity. The apple in your hand does not have identity as such. To suppose it does, is just a semantical concept, an arbitrary assumption in your worldview. To be more proper to reality, we should just see that there are only stable patterns around us. Stable pattern is something we point a finger at and say "an apple". Not even our "self" has identity. You are at most defined by what has accumulated into your worldview, but to say you are the same person you were yesterday is an arbitrary assumption, and in many ways wrong. We are literally like a wave on the ocean; just a stable shape, not formed of the same "stuff" at every moment, or indeed, at ANY moment. Moment, btw, is also an arbitrary assumption, as is clarified by relativity.

This also means there is no actual TOE out there. At best we can find the simplest way to *describe* reality, but we cannot comprehend how reality really is. For the simple reason that our comprehension is BASED on a worldview that is not rooted to truth, but is merely a self-supporting structure, a circle of beliefs. (If you are wondering, math too is a semantical concept, albeit based on explicit rules)

And to answer your question, reality is out there, causing our comprehension, yet it is beyond true comprehension.

2. Einstein said: "I think that a particle must have a separate reality independent of the measurements. That is: an electron has spin, location and so forth even when it is not being measured. I like to think that the moon is there even if I am not looking at it." Is this realism?

Like Einstein noted himself; our comprehension of reality is based on certain assumptions about reality. He took out the assumptions about simultaneity to make a consistent model with isotropic speed of light, which is an interesting instance of changing one's worldview from one coherent model into another coherent model. But here he is making certain assumptions about the metaphysical identity of things. A realist doesn't have to assume that an electron has spin, a location and so on before being measured, because we can only measure things with pieces of matter, and thus these properties of electron, indeed the whole electron as we think of it, can be a result of interaction between the measurement device and something else that is not measurable as it is by matter. This whole talk about particles and wave-particle duality and what not is a model based on semantical concepts, and I think it is evident that the difficulties to understand what is going on are because we are simply using wrong concepts to comprehend this. This is evident when we just keep in mind HOW we comprehend things in the first place.

So, while these assertions about electron being such and such regardless of so-called measurement may be wrong, to suppose our comprehension creates the moon is even more wrong.

3. In your opinion, is "realism" an assumption of Bell's Theorem? If so, where does it arise?

It seems to me that localism is a feature of realism only in so far that the ontology of relativity is right. My hopes on that are not particularly high though, so I have no problems at looking at models with non-local action, especially since many instances of non-locality are explainable in local terms if you just change the concepts you are using to comprehend the situation.

For example, ages ago people may have had certain assumptions about the reality of a rainbow. That it is an object that exists in space right where it seems to exist. If you make this assumption about the identity of a rainbow, you would find the rainbow to react to the motion of observer (react to "being measured") in a non-local fashion. It immediately moves when you move. How can that be? Does it know the future and react accordingly? Well no, the concept of rainbow was just royally wrong, what we see was always just an interference pattern on the observer. The rainbow does not exist without an observer. Sounds familiar?

Incidentally, I just started a thread "Quantum mechanics and spacetime" where I'm wondering how it's possible that Einstein was troubled by "spooky action at a distance" when at the same time he believed into static spacetime, and thus no spooky action at a distance makes sense even at a conceptual level (when, metaphysically, does the spooky action happen, Einstein? :), and also the spooky action is easily explainable as a deterministic phenomenon if you just change your concept of what light is more towards what it appears to be in terms of spacetime (a static connection that just exists in some static shape in spacetime).

Just a few related thoughts that popped into my mind while writing this.

1. The apparent paradoxes associated with time travel are a simple instance of us using wrong concepts to comprehend reality. Even with the idea of time travel over static spacetime there is no sense of "when" the time travel happened. It had always happened, or it had never happened. Simply put, some of our concepts of reality are wrong here.

2. The mainstream model about the big bang has equally mysterious conflict in its concepts. It is asserted that in the beginning there was an event where "spacetime" was first created, and for that reason it does not make sense to ask what was "before" big bang. Well, if the spacetime was created, this means the whole thing, the past and the future, was created. As such it makes no sense to assert that within the spacetime there is a moment "in the beginning" where "it was created". The box cannot contain itself. The concept of "event" does not fit into the idea of big bang. There can be no moment inside the spacetime that defines "when" it was formed! (All in all, the question of origins refers back to the question of "why is there reality?")

3. The method of science IS philosophy, but a form of philosophy that is in my opinion sorely lacking in "philosophic thinking". To scientists I say, either "just shut up and calculate", or be more careful with your assertions about reality, and understand that any assertions you make are more or less based on ARBITRARY way to understand the system we call reality. All the assertions above, even this one, is done based on my view. I hope others can find some meaningful thoughts in it.

vanesch

Sep5-06, 05:01 AM

This seems like philosophy and not physics to me but 'realism' or 'reality' are very easy to define in my mind.

Of course it is philosophy ! Talking about what is "realism" is metaphysical (and hence philosophical), because the essential discussion between "local/non-local realists" and "quantum physicists" is about the fundamental requirements of "reality" that has to be satisfied for something to be called "a physical theory". The "realists" tell the quantum physicists that they are in deep trouble because their theory (quantum theory) doesn't satisfy the metaphysical requirements a physical theory should satisfy, according to them. Nevertheless, this discussion is about physics: namely about what are the requirements for a theory to be a physical theory. But the discussion is not physics itself, given that we are defining what is/is not "acceptable physics".

When asked, most physicists would say that physics is building mathematical models which explain observations (theory), and doing experiments to verify mathematical models (experimentalists).
Realists put an extra requirement into this: they want 1) the mathematical models to be fair representations of "reality" and 2) they want observations to correspond to an observer-independent "reality" in a straightforward 1-1 way.

This sounds extremely reasonable, but QM fails the test at first sight.

Once we are at this point, we should examine more closely all the things that lie on the table, and the main discussion is here about the concept of "reality". Now, the specialists on that issue are philosophers, who have thought about this for quite some more time than physicists used to do (them usually being more occupied with the mathematics of their theories).

And it turns out that the concept of "reality" is not so evident, after all.

Reality is independent of observation in the strictest sense, but to humans, we must accept our 'personal' reality as a collection of sensory inputs to which we give meaning to, and draw meaning from. That which is beyond our 5 senses is unknown and cannot be known, period.

And what tells you with certainty that what your 5 senses tell you is any more "knowable" than what comes from "extensions" ? This is the kind of question philosophers have given a lot of thought to.

Now, as I said previously, it is of course desirable not to have to delve into these issues to do physics. It would be nice to be able to uncouple these issues from physics, and be able to postulate a physical reality which has a 1-1 correspondence with sensory experiences. As such, we could postulate a physical, objective reality totally independent of subjective observation, which, in one way or another, corresponds 1-1 to our subjective observation. This would be nice, and in fact, classical physics did that perfectly. However, I don't see why this "requirement of simplicity" should hold fundamentally. It is not because it would simplify our conception of nature (a clear picture of "physical reality" and a separate, rather fuzzy idea about where subjective experience comes from, but happily independent of the former) that things HAVE to be this way.
This vision of the world is what philosophers call "naive realism".

Even Plato didn't think the world was simple like this. So, nice as it would be, I think one cannot *require* it. If this requirement makes us put into the dustbin a highly successful theory such as quantum theory, then this is food for thought. What has to go ? Our "naive realism" requirement, or quantum theory ?

My main point of this idea of what 'true' 'reality' is, is that all conversations wishing to seek truth, should stay within the confines of our senses and the perceptions we create from these curriers of 'reality's' data.

I think that all conversations seeking "truth" are starting off badly.

vanesch

Sep5-06, 06:22 AM

Philosophy, sweet :)

1. What does realism mean to you?

I'm a strict materialist, so it means that there is a world out there, which is also the cause of conscious experience.

As a dualist, I'm going to challenge a few of the statements you make here. I know that it is not fashionable amongst scientists to fight materialism, but I take the challenge.

My main challenge to materialists is: tell me, from a strictly materialist viewpoint, under what conditions a physical system devellops conscious experience. Now, I know that I can get "answers" to that, but they are totally arbitrary (and depend strongly on the field of activity: from neurologists, computer scientists, zoologists... you get widely different answers which just redefine the word "consciousness" into one or other arbitrary physical property, often strongly antropologically centered). For instance, if you take a neurologist's viewpoint (memory, sensory perception and associative circuitry that has access to both, constructing a self-perception), then a PC with a web cam looking at its motherboard and running something like Photoshop is a conscious being...

In fuzzy language; Conscious experience is what happens when physical organism starts using such method of prediction that it builds a semantical worldview (=self-supporting, not representing "the truth", but merely "a way to comprehend") out of classifying the patterns it observers into "sensible objects" (with mere "assumptions") until it knows enough about the behaviour of such objects to be able predictions of systems become possible. One arbitrary assumption in such worldview is the assumption that there exists one's "self".

Let me say something totally crazy at first sight to illustrate my problem with it:
The question of course being what physical processes are being "methods". Is a crystal moving defects around building any worldview of which we might not have understood the significance under its sensory experience of sounds and vibrations ? Are the velocity fields in a turbulent flow of sufficient complexity in fact some form of "thinking" ?
To us, these seem like totally random events, but maybe to a thinking water flow, the electrochemical processes in a human brain seem totally arbitary.

How is a materialist going to define strictly what physical processes give rise to some subjective experience, and what not ?

So my point is that this problem of emergence of subjective experience is not solved by defining it away, and that it plays a potentially fundamental role in the way we define what is "an observation", which, in turn, is a fundamental concept in any scientific endaveour, given that theories are tested against observations (and hence subjective experiences).
It might be (see my previous postings) that both have nothing to do with one another, but this is, to me, not a strict requirement.

This is literally a hypothesis about the phenomenon of conscious experience existing on the basis of physical things (brains/neurons) expressing by their spatial/temporal form, an artificial model of the "world" around the organism, for the purpose of being able to predict things. We are not conscious of the world around us, but merely of this semantical model.

Well, recently I got into a discussion with someone who had to write a manager degree thesis in the medical sector. He's in the sector of the highly mentally handicapped, and the his subject is, how to motivate the low level staff by explaining them that these patients are really conscious human beings which can suffer as well as them. Indeed there's sometimes a serious problem of demotivation, often leading to mis treatment of the patients (not serious mistreatment, but daily rough handling and lack of care). To give you an idea: the average mental age of the patients is between 6 months and 1 year (although they are 30 - 50 year olds).

According to your definition, it is hard to say whether these are really "conscious beings": they almost make no predictions ! At best, they roll themselves in their excrements in as far as they have any controlled motricity.

His answer was in fact rather smart: Pascal's bet. We don't know if they are conscious beings or not. But let us imagine they are, after all, not. If we take care of them, then we're simply wasting our time and money. Now imagine they are, and we don't take care of them, and mistreat them. Then we are monsters.
It's worse to be monsters than to waste our time. So in doubt, let's be nice to them.

Consciousness is a side-product of the brain building such a worldview where certain the assumption about "self" has formed, and thus the surrounding world is interpreted in the form "this and that happened to me". The experience of free-will is what only exists in our semantical comprehension of the world, while in fact all our decisions are based directly or indirectly to the outside pressures (things we've learned, and how we interpret the situations according to things we've learned).

Simply put, we make our decisions mechanically based on the cumulated knowledge of our experiences, but we have a conscious experience of our self "searching for" the correct decisions from our worldview (thinking), as if there is a fundamental "self" with free will making choices (well, pretty simple philosophical excercises already show that free-will is a non-sensical thing at a conceptual level already, plus many experiments show that no, we are not aware of having made a decision when the physical state of the brain already reveals the choice has been made. This should not be a surprise to anyone dabbling in materialistic philosophy)

Yes, I agree with the free will thing. But that's not the discussion. The discussion is about the emergence of a subjective experience.
So the point is: when is there, and when is there not, within a physical structure, an 'awareness' ?
When does a physical process lead to an awareness, and when not ? Imagine you think up a definition which places your body outside of it. So according to your definition, you are not conscious, after all. Does that make sense ? So in what way are you then allowed to think up criteria which make up your definition of "consciousness" ?
In fact, you intuitively "know" that people are conscious, and you try to think up a set of conditions so that they all fall in the category of "conscious beings" while keeping out obvious counter examples, like PC's, robots, and ants. In other words, you try to fit humans "after the fact".
I'm sure that in the 16th century, a thing playing a strong chess game would be considered as a conscious thing. Simply because at that time, one could not think it possible for something else but a human to do so.

So we could say that being a materialist is to an extent an arbitrary choice. Why I'm not considering idealism then? Because it tends to lead either a solipsism, or to the idea that some kind of god is "feeding us with our ideas".

I don't think this is the only issue possible (I'm not religious for instance). I think materialists try to deny an aspect of the world, which is the existence of subjective experience. That doesn't mean one has to deny the link between this subjective experience and the material world, but it means that one cannot *derive* it from the reductionist description of the material world, and that you need some *extra input* to say when, and when not, subjective experiences can emerge from a physical structure.
(this is in fact as close to materialism that a dualist can come: yes, subjective experience finds its origin in the material world, but "it didn't have to happen"). The problem is that most if not all materialist arguments are strictly behavioural, and hence miss the point, because the *behaviour* of a physical structure being governed by physical laws, it doesn't NEED any emergence of subjective experience for it to behave that way. Hence behaviour can never be a proof for the existence "inside" of any subjective experience. Which excludes any inquiry into subjective experience from any experimental inquiry, *except for one's own*.

And also many experiments as judged with a materialistic view say a lot about how our "ideas" exist physically, and with that knowledge it is just too naive to think that "ideas" are fundamental. Simply put, these philosophies make assertions about some very very very complex behaviours being actually fundamental (like the sentient behaviour of god)

The "Platonic world of ideas" is of course not the world of *human* ideas, but the abstract concept of mathematical structures.

And why would anyone believing in solipsism try to convince anyone else that world is solipsistic? HELLO??!

Because it's fun to talk to one's own chimera ? :tongue:

Why I'm not considering dualism, is because it too makes certain assumptions about fundamentals that become apparently naive very quickly.

I think you're thinking of only specific forms of dualism here. As I said, dualism essentially says that reductionist physical laws are not sufficient to explain the emergence of subjective experiences, simply because those physical laws would do fine all by themselves without such emergence. As such it becomes fundamentally impossible to *derive* from those physical laws, when subjective experiences emerge, and when not, and it is not because you arbitrarily decree that something of the kind happens for certain systems, that this is so. There are dualist visions with souls, deities and all the panoply you like, but this is, IMO, not the essence. The essence for me is that there is no a priori way to *derive* exactly when subjective experience emerges, and when not, from reductionist laws.

Now, after this highly philosophical debate, what does this have to do with quantum theory ?

Well, MWI proponents such as myself claim that we've been all wrong about *exactly which elements of physical reality* are to be suffering subjective experience. In classical physics, this corresponds to sets of physical degrees of freedom in certain configurations (say, living brains), while in MWI, this corresponds to certain *slices of state space* spanned over these degrees of freedom.

But in order to even be able to say this, we need some freedom in postulating freely what is, and what is not, potentially corresponding to a subjective experience independently of "physical reality" (and hence we need a minimum of "dualism"). If we can for instance *postulate* that certain quantum states of a restricted set of degrees of freedom (such as the material degrees of freedom of a brain) correspond to subjective experiences, and others don't, and we now find that the "state of the universe" simply contains a superposition of said states, then we could decree that these are "parallel" and slightly different subjective experiences, each corresponding to the SAME degrees of freedom (the brain). That's different than the view that there are ghosts in the brain or anything. But it is not a strictly materialist viewpoint, because what is, and what is not, a material state corresponding to an experience and not, is not derivable from the physical laws themselves, and needs to be postulated separately.

So in my view, our understanding of reality is based on making arbitrary assumptions about it until we have a coherent picture for making predictions. Any behaviour is a case of prediction. ANY. Walking, talking, inventing, thinking... Our understanding of anything is literally a case of some pattern being classified into such and such concept that we assume to behaves in such and such ways due to past experiences or assumptions about combinations of concepts, and because of this it is also apparent that no worldview is "correct" or "true" to reality, but merely a method of comprehending it. This is why we can look at any system and understand it in a number of different ways.

I agree here. As I said: reality is a working hypothesis that allows one to "comprehend" the world, which is, for a being, essentially reduced to its subjective experiences. It's a way of classifying subjective experiences.

This also means that ANY form of realism is to an extent naive realism. Even mine, as it also is based on semantical concepts. We are always forced to make arbitrary assumptions about things that "are fundamentally real", while not even this very classification of reality into sensible objects is in any way "correct" way to see the world, yet it is the ONLY way we can comprehend anything.

I don't see, for instance, how an MWI view (which, I think, satisfies all of the above criteria), can be called a form of naive realism...

No, we should not interpret reality as if shadows have identity. It is just a stable pattern. We should not imply ANYTHING to have identity. The apple in your hand does not have identity as such. To suppose it does, is just a semantical concept, an arbitrary assumption in your worldview. To be more proper to reality, we should just see that there are only stable patterns around us. Stable pattern is something we point a finger at and say "an apple". Not even our "self" has identity. You are at most defined by what has accumulated into your worldview, but to say you are the same person you were yesterday is an arbitrary assumption, and in many ways wrong. We are literally like a wave on the ocean; just a stable shape, not formed of the same "stuff" at every moment, or indeed, at ANY moment. Moment, btw, is also an arbitrary assumption, as is clarified by relativity.

... or a state in statespace ? :cool:

This also means there is no actual TOE out there.

I don't see how this can be decided, one way or another. To me, a TOE is a logically consistent model which can describe all our observations.
That doesn't mean that it may not turn out to be false one day, or that several of them can be found (or none ?), but I think the question of the existence of such a model, at any time, is an entirely undecided question.

3. The method of science IS philosophy, but a form of philosophy that is in my opinion sorely lacking in "philosophic thinking". To scientists I say, either "just shut up and calculate", or be more careful with your assertions about reality, and understand that any assertions you make are more or less based on ARBITRARY way to understand the system we call reality. All the assertions above, even this one, is done based on my view. I hope others can find some meaningful thoughts in it.

I couldn't agree more :approve:

selfAdjoint

Sep5-06, 06:43 AM

My main challenge to materialists is: tell me, from a strictly materialist viewpoint, under what conditions a physical system devellops conscious experience. Now, I know that I can get "answers" to that, but they are totally arbitrary (and depend strongly on the field of activity: from neurologists, computer scientists, zoologists... you get widely different answers which just redefine the word "consciousness" into one or other arbitrary physical property, often strongly antropologically centered).

1) God of the gaps. Arguing from the incomplete state of current research to deny the relevance of any research.

2) For goodness sake do this kind of arguing on a philosophy forum, not a physics one! A moderator would have perfect justification in deleting your post, and with your green badge, you're supposed to be one of the good guys!.

vanesch

Sep5-06, 07:59 AM

2) For goodness sake do this kind of arguing on a philosophy forum, not a physics one! A moderator would have perfect justification in deleting your post, and with your green badge, you're supposed to be one of the good guys!.

I know that some moderators would like to delete my post :biggrin:, but I really do not agree with that, for the following reason. The entire argument about (local) realism (which was the original topic) requirement is a subtle philosophical argument, *and* is relevant to quantum theory - especially "weird" versions of it like MWI. I don't think I've drifted into any mysticism or anything else.

The two fundamental questions, which are central to any form of understanding of quantum theory, its critique by local realists, and proposed answers by MWI proponents, are:

- what is "reality" ?

- what is "observation" ? (very close to: what is perception, and from there "subjective perception")

Now, it is not my fault that these are highly philosophical topics, but they are nevertheless relevant to quantum theory. They are not particularly relevant to, say, optics, or stellar structure, or calculations of 4th order corrections to electroweak interactions, but they ARE entirely relevant to the foundations of quantum theory, as can testify the many ponderings of a kind that have been generated over the 80 years of its existance, by many of its prominent contributors as well as detractors. You cannot seriously propose to have discussions about quantum theory without touching upon the subject from time to time.

That doesn't mean that we allow crackpottery under the guise of "quantum philosophy", but I don't think that there was much of that in this thread. Instead, the metaphysical requirements of what a physical theory should satisfy have been touched upon, as this is the main discussion point between realists and others (and the original topic).

Also the concept of what exactly is an observation, and how is it related to any potential reality, is touched upon. Personally, I really don't see the utility of any discussion about quantum theory if these issues, which are central to its foundations, cannot be talked about.

I haven't seen, in this thread, any derivations into lala land, any shouting contests, and I had the impression that its participants (me included) found the discussion interesting and thought-provoking. We've remained close to the original topic, and - as I tried to say - it *is* relevant to quantum theory. What more could you ask ?

Now, if you want to displace this thread to the "philosophy of science" forum, be my guest ! It's clearly an interdisciplinary topic, touching upon the philosophical questions raised by the formalism of quantum theory, so it belongs, IMO, to both. It's specific relevance to quantum theory in particular, however, make me believe it can stay here without problem.

Careful

Sep5-06, 08:13 AM

If one understands under physics :
(a) development and discussion of well known theories
(b) construction of and debate about no-go theorems as long as no scientific counterexample is given how to bypass the latter

then let me recall that I have said in one of my first posts about Bell inequalities that such discussion belongs in the philosophy forum. If on the other hand, physics is also about expressing consistent world views or to present such possible candidates (which I believe is essential for science), then I share the opinion of Vanesch (even if I think MWI is nuts :smile: ).

One cannot feel neither understand these deep conflicts in our understanding without going through this kind of ``crackpottery''; quantum gravity is full of this kind of conflicts.

Careful

vanesch

Sep5-06, 08:36 AM

If on the other hand, physics is also about expressing consistent world views or to present such possible candidates (which I believe is essential for science), then I share the opinion of Vanesch (even if I think MWI is nuts :smile: ).

I think the human mind is such that it needs some kind of "consistent world view" in order to be able to make judgements on how to extend/modify/understand it, and as such, I would be of the opinion that anyone trying to do some fundamental theoretical research in physics without having thought about these issues at least once, is totally misguided. It's different for people simply wanting to *apply* known theories to solve practical problems (which is, no matter how boring it may sound, the main activity of an overwhelming lot of physicists, me included), but that's not how you get young minds interested into the topic!

If you look at the threads here, *a large part* of it touches upon half-philosophical issues, so I really don't see what's wrong with talking about that now and then.

As MWI is concerned, I said several times too that intuitively, I also find it "nuts". Nevertheless, I think it has its place because at least, "it bites the bullet". Given the strangeness of the linear quantum formalism, it pushes the consistency of the view to the extreme and pushes your nose in the dirt you'd have liked to whipe under the carpet (as do many other interpretations). So I like it from the purely logical PoV. It is, strictly logically (and not intuitively) speaking, the most consistent view on quantum theory. So IMO, which is of course entirely personal, I think MWI is the next best thing after giving up on linear quantum theory all together or finding out how to modify the formalism in such a way that it becomes "naive realist" again (and that's then no quantum theory anymore).
I'm not the only one taking on that view - Penrose is with me here (and you can't call him a local realist, nor an MWI proponent) for instance.

One cannot feel neither understand these deep conflicts in our understanding without going through this kind of ``crackpottery''; quantum gravity is full of this kind of conflicts.

Indeed, I see this as a kind of brainstorming on the foundational level. Trying to put all the "evident and intuitive truths" as much aside as possible, and trying to find out what are still the logical requirements.

This is of course a totally different activity than trying to calculate some correction to one or other spectroscopic transition. I think one needs to be able to do both.

Careful

Sep5-06, 08:54 AM

** I think the human mind is such that it needs some kind of "consistent world view" in order to be able to make judgements on how to extend/modify/understand it, and as such, I would be of the opinion that anyone trying to do some fundamental theoretical research in physics without having thought about these issues at least once, is totally misguided **

Correct, there is much less physics around than mathematics.

**
As MWI is concerned, I said several times too that intuitively, I also find it "nuts". **

Hehe, don't take it personally :rofl: just teasing a bit.

** Nevertheless, I think it has its place because at least, "it bites the bullet". Given the strangeness of the linear quantum formalism, it pushes the consistency of the view to the extreme and pushes your nose in the dirt you'd have liked to whipe under the carpet (as do many other interpretations). **

Right, it was the MWI type of nonsense which was the drop too much for me, in that sense it works perfect. :cool:

** I think MWI is the next best thing after giving up on linear quantum theory all together or finding out how to modify the formalism in such a way that it becomes "naive realist" again (and that's then no quantum theory anymore). **

How revolutionary.

**
I'm not the only one taking on that view - Penrose is with me here (and you can't call him a local realist, nor an MWI proponent) for instance. **

Hmm, I am not sure about your first statement, but true Penrose is not a LOCAL realist, but a realist nevertheless.

**This is of course a totally different activity than trying to calculate some correction to one or other spectroscopic transition. I think one needs to be able to do both.**

I agree, there is a very useful interplay between them moreover. Making a difficult calculation is 1, making a difficult useful calculation is 2. Funny enough, many useful calculations are usually relatively ``easy''. :wink:

Careful

DrChinese

Sep5-06, 12:03 PM

From Bell's original "On the Einstein Podolsky Rosen paradox":

Circa Formula (15)... (http://drchinese.com/images/BellVectorC.jpg)

In my opinion, this is where Bell introduces realism mathematically. Previous to this point, he had setting a for Particle 1 and setting b for Particle 2. By introducing setting c, he is explicitly adding the assumption that there is a third setting c to discuss even though there are only 2 particles. By extension, there could also be hypothetical settings d, e, f, etc.

So Bell is saying that a local realistic theory (if it exists) would be more complete than quantum theory because of this hypothetical c vector. Do you agree with my characterization of Bell in this regard? If not, is there another spot in which the assumption of realism is expressed?

AnssiH

Sep5-06, 01:20 PM

As a dualist, I'm going to challenge a few of the statements you make here. I know that it is not fashionable amongst scientists to fight materialism, but I take the challenge.

Sweet :) I can understand it is hard to be a dualist in this materialistic world.

My main challenge to materialists is: tell me, from a strictly materialist viewpoint, under what conditions a physical system devellops conscious experience. Now, I know that I can get "answers" to that, but they are totally arbitrary (and depend strongly on the field of activity: from neurologists, computer scientists, zoologists... you get widely different answers which just redefine the word "consciousness" into one or other arbitrary physical property, often strongly antropologically centered). For instance, if you take a neurologist's viewpoint (memory, sensory perception and associative circuitry that has access to both, constructing a self-perception), then a PC with a web cam looking at its motherboard and running something like Photoshop is a conscious being...

Yeah, my experience too is that most materialists don't really even understand the problem of consciousness, and some of them slip into panpsychism and such things. The materialistic paradigm, when taken to its ultimate conclusion, says quite clearly that we cannot actually get the answer; we cannot exhaustively understand why there is a conscious experience. I often have a lot of trouble explaining my ideas even to other materialists, because usually they haven't really taken their view far enough to realize that if materialism is true, we are physically limited to comprehend our comprehension processes!

"But if there is only physical things, why wouldn't we understand it" they say. Every word in the following is painfully inaccurate to describe the reality or even my view, but you can grasp the reason why my assertion must be true in materialistic paradigm;

If it is true in any sense, that it is the spatial/temporal patterns in the brain that express the concepts we are consciously aware of, these patterns themselves cannot possibly bend into the shape that is expressing how the very same expressions are our comprehension. A snake that is expressing a box by bending into a square shape, cannot bend into a shape that is expressing how the snake itself is expressing the box. This must be understood absolutely. Our ideas are not "unlimited", there are physical limitations to them, and those limitations are the way we merely express reality in some arbitrary ways (Philosophical pondering also reveals that reality looks, sounds and feels quite a bit different than it seems to us).

Most materialists just don't get this. Instead they claim that we understand what happens in the brain if we just look at a high-resolution real-time brainscan and look how poking the brain causes some sorts of conscious sensations. They don't understand, that in a strict materialistic paradigm, any understanding of neurons or the electro-chemical patterns that occur in them must literally be arbitrary expressions about reality. Concepts like neurons, electrons and chemicals are semantical concepts.

We can still imitate nature and build conscious machines (if we only believe they are conscious when they claim they are), and we can understand that there is a correlation between the spatial/temporal patterns, but we must understand there is no identity between them; we are not aware of the spatial/temporal patterns, but merely of our semantical expressions that we understand as "spatial/temporal patterns".

So really the only answer I can give you is the mere hypothesis that says a conscious experience exists when a system builds such and such worldview where there exists a semantical assumption about the existence of one self (did people grasp what I mean with semantical worldview btw?). There are many indications to base this hypothesis on, but still it cannot be lifted up to be more than hypothesis by the very principles upon which it exists. Also one must understand that I am using semantical concepts to describe this process, and as such I am painting a view that is very much inaccurate from reality. With a little thought one can easily see which parts are clearly inaccurate, but it is hard to think of better concepts to describe the process.

Let me say something totally crazy at first sight to illustrate my problem with it:
The question of course being what physical processes are being "methods". Is a crystal moving defects around building any worldview of which we might not have understood the significance under its sensory experience of sounds and vibrations ? Are the velocity fields in a turbulent flow of sufficient complexity in fact some form of "thinking" ?
To us, these seem like totally random events, but maybe to a thinking water flow, the electrochemical processes in a human brain seem totally arbitary.

How is a materialist going to define strictly what physical processes give rise to some subjective experience, and what not ?

Yeah, this is exactly where materialistic view starts to shake if one hasn't really thought it through. Most materialists haven't. My answer lies in how I suppose the worldview exists physically. Let's say you see an apple which causes such and such pattern of activity in your brain. Obviously this very pattern does not possess a metaphysical "meaning" of apple in any form. It doesn't mean that if you cause the same exact pattern into a rock, it has an experience of an apple, or indeed, even if you cause the very same pattern to a "fresh brain" it has an experience of apple. The only reason why the pattern means anything at all is that your brain has built such a worldview against which the pattern has any meaning at all. Your worldview has certain assumptions about reality, one of which is a certain pattern that has been classified as "apples". There are more specific ideas about the physical details of how such worldview and patterns might exist (Like at "On Intelligence" by Jeff Hawkins).

And btw, in this framework not only the system needs to recognize an apple in this sense, but it actually has to interpret the whole experience of seeing an apple in form of "I saw an apple", for which your worldview must contain some assumptions about your own existence. If you don't understand you exist, in what form do you have a memory of any of your past experiences? This is why there is infant amnesia; babies haven't assumed yet that they indeed do exist and there is such a concept as existence etc. How could you remember your infant experience when you possibly could not even store any memories in the form of something having happened to you? Infants don't actually have a conscious experience in this view. I think we all have had the experience of becoming progressively more conscious of our own self as a kid. The very first memories are the first experiences we started to interpret in the form of something happening to our self.

So is a storm conscious? No, there is no basis for stability and learning the way there needs to be. Most animals are not conscious. They cannot learn enough to make assumptions about existence. Remember, the only reason our brain builds such a worldview is so that the organism can make predictions; it's a survival method. Computers are not conscious, they just follow explicit rules. There is no sense of reality being expressed inside them the way there is in brain.

I also understand this does not actually exhaustively explain consciousness, there is a leap of faith that one must take to believe this.

Well, recently I got into a discussion with someone who had to write a manager degree thesis in the medical sector. He's in the sector of the highly mentally handicapped, and the his subject is, how to motivate the low level staff by explaining them that these patients are really conscious human beings which can suffer as well as them. Indeed there's sometimes a serious problem of demotivation, often leading to mis treatment of the patients (not serious mistreatment, but daily rough handling and lack of care). To give you an idea: the average mental age of the patients is between 6 months and 1 year (although they are 30 - 50 year olds).

According to your definition, it is hard to say whether these are really "conscious beings": they almost make no predictions ! At best, they roll themselves in their excrements in as far as they have any controlled motricity.

They probably are not conscious. To be conscious would require them to form memories in the sense of something happening to them. Have they learned that they exist? Probably not. Maybe some have in some limited sense? Who knows.

Yes, I agree with the free will thing. But that's not the discussion. The discussion is about the emergence of a subjective experience.
So the point is: when is there, and when is there not, within a physical structure, an 'awareness' ?
When does a physical process lead to an awareness, and when not ? Imagine you think up a definition which places your body outside of it. So according to your definition, you are not conscious, after all. Does that make sense ? So in what way are you then allowed to think up criteria which make up your definition of "consciousness" ?
In fact, you intuitively "know" that people are conscious, and you try to think up a set of conditions so that they all fall in the category of "conscious beings" while keeping out obvious counter examples, like PC's, robots, and ants. In other words, you try to fit humans "after the fact".
I'm sure that in the 16th century, a thing playing a strong chess game would be considered as a conscious thing. Simply because at that time, one could not think it possible for something else but a human to do so.

Or an amoeba, or an ant colony. Ant colony btw is a fascinating thing because we classify the ants as individuals, but in many senses it is the colony that is the organism. And like it is with the colony of cells that is our brain, we have to think about how could it be that the ant colony was conscious instead of the individual ants (it is not the individual neurons that are conscious; one definition of consciousness is a single subjective experience out of large amount of objects, or out of some spatial area). So like it is in my hypothesis, conscious experience would be literally caused by the ants of the ant colony falling into certain patterns (due to "outside" pressure) in order to produce other patterns that is the prediction of future, causing the organism to react to the outside pressure in a predictive manner. And it would not be exactly correct way to see it as if it is the ants or the hive that is conscious, but that conscious experience is a process. A process is different from the platform that causes it. This is still a materialistic view, because the process that the physical system causes cannot be detached from the physical system. Consciousness to brain is like combustion to wood.

More thoughts about phenomenal self here:
http://www.amazon.com/Being-No-One-Self-Model-Subjectivity/dp/0262633086/sr=8-1/qid=1157482941/ref=pd_bbs_1/103-6597748-8122216?ie=UTF8&s=books

I don't think this is the only issue possible (I'm not religious for instance). I think materialists try to deny an aspect of the world, which is the existence of subjective experience.

I actually get that feeling a lot from fellow materialists... I think there are couple of reason to it. First is that it is actually pretty hard for some people to see the problems associated with consciousness, because consciousness is too obvious or a natural thing in their worldview to even seem odd at all. It takes quite a bit of thought to see the problems. The second reason is that it is very hard to build a mechanical model which would explain the subjective experience, for the reasons I mentioned before. Also one must banish many invalid ideas about reality before they can even begin to build mechanical models. Yet they choose to be materialists because it feel simply too arbitrary to assume consciousness is like some sort of magic sauce poured onto the brain. That view is not very easy to come in terms with either, unless one happens to have a very religious upbringing I suppose.

So people choose to be materialists on the basis of certain principles, and assume that "somehow" subjective experience emerges, "nevermind that we don't know how yet".

I think you're thinking of only specific forms of dualism here. As I said, dualism essentially says that reductionist physical laws are not sufficient to explain the emergence of subjective experiences, simply because those physical laws would do fine all by themselves without such emergence. As such it becomes fundamentally impossible to *derive* from those physical laws, when subjective experiences emerge, and when not, and it is not because you arbitrarily decree that something of the kind happens for certain systems, that this is so. There are dualist visions with souls, deities and all the panoply you like, but this is, IMO, not the essence. The essence for me is that there is no a priori way to *derive* exactly when subjective experience emerges, and when not, from reductionist laws.

Then our views are quite close to each others, with the main difference being that I describe on mechanical terms why there can be no way to derive exactly when (or rather why) a subjective experience emerges. Best we can do is find the correct components, put them together, and hope for the best. We cannot actually know if our artificial intelligence system then is conscious or not, just like we cannot know if the world is solipsistic or not.

I don't see, for instance, how an MWI view (which, I think, satisfies all of the above criteria), can be called a form of naive realism...

It can because it too is necessarily based on arbitrary assumptions about what things are fundamentally real. You cannot comprehend reality without invoking the idea of things. You cannot comprehend reality without using concepts of some sort. But reality itself does not work on concepts. And if relativity is real, even time is arbitrary concept that does not metaphysically exist.

... or a state in statespace ? :cool:

Well, with "moment" being an arbitrary assumption I was referring to relativity saying that there is no universal "now"-moment, instead there is only one for each inertial frame. (Where of course inertial frames are arbitrary assumptions or concepts)

Careful

Sep5-06, 01:36 PM

DrChinese

Sep5-06, 01:56 PM

...even Vanesch agrees that in his world, it would be impossible to distinguish the ``zombies'' from himself.

Careful

None of the zombies in my neck of the woods possess the intellect of Vanesch. On the other hand, there are a lot of MWIers in the lot... :tongue:

AnssiH

Sep5-06, 02:59 PM

***
Yeah, my experience too is that most materialists don't really even understand the problem of consciousness, and some of them slip into panpsychism and such things. The materialistic paradigm, when taken to its ultimate conclusion, says quite clearly that we cannot actually get the answer; we cannot exhaustively understand why there is a conscious experience. ***

Hmmm, you will have to explain yourself here. You might start by defining a conscious experience

Well, it is notoriously difficult to define conscious experience. I think one of the more meaningful definitions is that there exists a singular experience over some system consisting of many parts. Like, panpsychisms assert that everything is conscious, that there is consciousness simply because reality "hits the brain", and every physical reaction is a case of conscious experience to the object that is doing the reacting.

The obvious problem with this is that we cannot define what is an object. Naive realist could say that a neuron too, has a subjective experience, but that would just mean a colony of molecules is having a subjective experience. A brain having a subjective experience is not trivial to explain because here too an arbitrary collection of atoms is having the experience. Why?

So that's why consciousness could be defined as a "singular experience that occurs to a colony of things", and for that reason it should be seen as the emergent function of the colony; a function that the whole system has while none of its parts have it. Just like ice is not slippery because it is made of slippery atoms, but because friction is an emergent function of colonies of atoms. (IF that's the way your semantical mind chooses to see it)

Anyway, the reason why we cannot expect to exhaustively understand why this emergent feature exists under certain conditions, is what I said about the nature of our comprehension. It is pretty obvious that when we have a conscious experience of anything (or rather "when there exists a conscious experience)", we don't actually experience reality itself, but we experience the artificial model of reality built by our brain. We can literally only understand an artificial model about these artificial models; this understanding too is based on huge amount of completely semantical concepts and arbitrary assumptions. There is an infinte regress here that we cannot get around.

Or think about the difference between looking at your brain activity from a brain scan and actually understanding the reality of that brain activity without using any arbitrary concepts. While you can find a correlation between certain pattern and thinking about an apple, this comprehension is just a semantical concept about correlation between certain visual pattern and apples. It says nothing about why there exists a correlation.

Another way to put it, when we try to pin down the metaphysical reasons of conscious experience, we must do so using many many many concepts and assumptions about reality, some of which lead to idealism, some to (naive) materialism, some to dualism, some to panpsychism and so on, but all of them are fundamentally about sensible objects and their relationships, and this is not because world would be fundamentally made out of "objects", but merely because in order for a physical system to make predictions about physical reality around it, it needs to classify reality into sensible objects, so to make assumptions about their relationships. The way we understand the world in objects such as particles and waves and what have you, is probably not the way the world metaphysically is at all. Yet that's the only kind of understanding we are capable of!

There are in fact many other ways to come to conclude that this so-called mind-body gap cannot be crossed even in principle.

RandallB

Sep5-06, 05:34 PM

In my opinion, this is where Bell introduces realism mathematically. Previous to this point, he had setting a for Particle 1 and setting b for Particle 2. By introducing setting c, he is explicitly adding the assumption that there is a third setting c to discuss even though there are only 2 particles.

So Bell is saying that a local realistic theory (if it exists) would be more complete than quantum theory because of this hypothetical c vector. Do you agree with my characterization of Bell in this regard? If not, is there another spot in which the assumption of realism is expressed?I think I understand what you’re saying; but I don’t I agree with the premise that Bell was establishing a “mathematical” assumption of naive local realism.
Or if you allow me to avoid calling it “naive”, can I call it common realism or common local realism to distinguish that HVT version from non-local theories like MWI, BM, SED etc. that have their own version of local within a non-common reality.

I see Bell Theorem as based on applying logic mathematically to provide a test for theories to show themselves as logically viable or not. Bell intended to give the simplest theory (the Common Local Realist) the chance to prove itself viable, with the idea that the simplest and more complete explanation is correct.
Thus, Common Local Reality would not rise from the Bell Theorem or any assumptions in it, but from the proof, a Local Realist might use to pass the logic of the theorem – which the LR has been unable to do for the Common Local case.
QM of course passes the test based on Uncertainty Principle not requiring common local realism. Other theories technically pass the test within their own non-common version of local.
In fact [b]if[\b] Common Local Reality were to provide an answer, I don’t think Bell alone would declare QM and others as “wrong” (even though accurate) and Common Locality as “right”, but our preference to accept Occam's point that the simplest and most complete theory is preferred would.
In addition, I do not see where Bell can (nor was ever intended to) select between those theories that do pass its logic. My guess is Occam would tip his hat to QM, if not hang it there till some better proof came from one of the non-common local theories.

By the way, with the intent of “naive” so easily misinterpreted, do you think my use of “common” is a fair and common sense way to distinguish between naive locality and other forms of locality without being confusing?

DrChinese

Sep5-06, 06:30 PM

I think I understand what you’re saying; but I don’t I agree with the premise that Bell was establishing a “mathematical” assumption of naive local realism.
Or if you allow me to avoid calling it “naive”, can I call it common realism or common local realism to distinguish that HVT version from non-local theories like MWI, BM, SED etc. that have their own version of local within a non-common reality.

I see Bell Theorem as based on applying logic mathematically to provide a test for theories to show themselves as logically viable or not. Bell intended to give the simplest theory (the Common Local Realist) the chance to prove itself viable, with the idea that the simplest and more complete explanation is correct.
Thus, Common Local Reality would not rise from the Bell Theorem or any assumptions in it, but from the proof, a Local Realist might use to pass the logic of the theorem – which the LR has been unable to do for the Common Local case.
QM of course passes the test based on Uncertainty Principle not requiring common local realism. Other theories technically pass the test within their own non-common version of local.
In fact [b]if[\b] Common Local Reality were to provide an answer, I don’t think Bell alone would declare QM and others as “wrong” (even though accurate) and Common Locality as “right”, but our preference to accept Occam's point that the simplest and most complete theory is preferred would.
In addition, I do not see where Bell can (nor was ever intended to) select between those theories that do pass its logic. My guess is Occam would tip his hat to QM, if not hang it there till some better proof came from one of the non-common local theories.

By the way, with the intent of “naive” so easily misinterpreted, do you think my use of “common” is a fair and common sense way to distinguish between naive locality and other forms of locality without being confusing?

Well, I don't think there is an issue of "naive" or not present. I think that any local realistic theory MUST acknowledge that there are definite, specific values for all observables at all times; but more specifically, that there are specific spin values independent of the act of observation. So either you agree with this view, or show what a realistic theory looks like that DOES NOT have these characteristics. (We already know that Bohmian Mechanics, by this definition, is non-local realistic.)

So again, I return to the mathematical formalism (http://drchinese.com/images/BellVectorC.jpg) of Bell to serve as a specific definition.

Chaos' lil bro Order

Sep5-06, 09:35 PM

And what tells you with certainty that what your 5 senses tell you is any more "knowable" than what comes from "extensions" ? This is the kind of question philosophers have given a lot of thought to.

I think that all conversations seeking "truth" are starting off badly.

Please define 'extensions' for me, I am not quite sure what you mean by this. Also, please keep your posts briefer and succincter if you can. Pack alot of information into a smaller package. I struggle to read 1000 word posts for fun in my free time.

Any coversation seeking the truth is the most valid conversation you could possibly have, so I see no reason to say it starts off badly.

I don't see what the whole debate about 'reality' is... We must assume there is nothing beyond our 5 senses, because to suggest otherwise leads us to hypotheticals that cannot be known. And unless posing such hypotheticals leads to developing a physical technique that uses our senses to delve into them and pull out probabilistic results, such speculation is irrelevant to the pursute of truth. QM is very valid as physics because it makes probabilistic predictions. Even if its various models are completely wrong about the true 'physical' nature of the processes it tries to describe, it is irrelevant to humans, because the predictions match the physical phenomena so precisely. For example, if I place a frog on my desk and hide it from my view with a bristleboard and then set up a mirror so i can see the hidden frog in a reflection, I can observe the frog's movements and make predictions about how it can and cannot move. As long as I understand the physics of the mirror, I can perform the neccessary operations on the mirrored data and transform it into the same data I would see if I removed the bristleboard and looked straight at the frog. Both observations of the frog, mirrored and strightforward are equally valid and equally true, regardless of whether I can actually perform the correct operations. No point of reference holds water over another point of reference. But what good would it do me to speculate that there is a rabbit beside the frog if I cannot sense it through my vision by either the mirrored or straightforward view? None. Absolutely none.

Therefore, there is only one 'reality', the reality that we can perceive with our senses. If we gain a 6th sense, or our 5 senses improve in sensitivity and scope, then, reality will expand to us. If I had a 6th sense that could perceive the hidden rabbit, I will then admit it into reality, but until this point, there is ABSOLUTELY no point in speculating and discussing whether a rabbit exists behind the bristleboard.

The only purpose in discussing things we cannot know is to collectively work out methods by which to know them. All else is speculative madness and does nothing to improve the human knowledge pool. Which, after all, is the true goal of humanity. No more, no less.

Careful

Sep6-06, 01:13 AM

Careful

Sep6-06, 01:24 AM

** Well, I don't think there is an issue of "naive" or not present. I think that any local realistic theory MUST acknowledge that there are definite, specific values for all observables at all times; but more specifically, that there are specific spin values independent of the act of observation. So either you agree with this view, or show what a realistic theory looks like that DOES NOT have these characteristics. (We already know that Bohmian Mechanics, by this definition, is non-local realistic.) **

I don't see why, an observable could just be a coarse grained property and those are not necessarily all well defined at each moment in time (like temperature in a non equilibrium situation). But that is not the point I guess, you basically refuse to accept an extension of reality (way less crazier than string theory) to solve the paradox.

Careful

AnssiH

Sep6-06, 06:12 AM

**
I think one of the more meaningful definitions is that there exists a singular experience over some system consisting of many parts. Like, panpsychisms assert that everything is conscious, that there is consciousness simply because reality "hits the brain", and every physical reaction is a case of conscious experience to the object that is doing the reacting. **

Ok, a coarse grained thing. Fine, why don't you just put in some central information processing system in, like in a computer ?

Because even if we have labeled something as "central system", it doesn't mean this system experiences whatever occurs to one of its parts. Calling something central is literelly just a label we put on an object, it doesn't mean it is an object in a metaphysical sense any more than any 1000 randomly selected atoms are. It is just a collection of logic gates, which are collections of other things, etc... It's not different from a sewer system then. This whole idea about a "CPU" knowing what happens to one of its ports is just as non-sensical as saying a city knows what is happening in one of its parking lots. We are just tossing around semantical concepts, and in particular our way of seeing world as objects is the problem here.

**
The obvious problem with this is that we cannot define what is an object. Naive realist could say that a neuron too, has a subjective experience, but that would just mean a colony of molecules is having a subjective experience. A brain having a subjective experience is not trivial to explain because here too an arbitrary collection of atoms is having the experience. Why? **

Euh, I am not sure wheter each part of the brain or the colony has the *same* experience.

Yeah they don't, but there is a singular experience that the whole colony is having, which is not the experience of any single part of the colony. Plainly put, stimulating one part of the brain causes us a conscious experience of something, and stimulating a completely different part of the same brain also causes a conscious experience of something. Neither of the parts need to know about each others, yet there is a subjective experience of both stimulations.

Obviously there is connection between these areas, but it doesn't mean we are some sort of special neuron somewhere where everything is ultimately focused (and even if you supposed we are, neuron too has many parts, and in the end you start thinking we are some sort of special atom or some infinitely small area inside the atom or something). It just means it is wrong to understand the reality of consciousness in the form of something happening to some "object", for the whole idea about objects is arbitrary. I.e. there is a phenomenal self. There is no object that is conscious, but more properly conscious experience is occurring as a process or interaction between the so-called objects.

And conscious experience is really the only case where we could say there is a singular experience about the activity happening to a large collection of so-called "things".

It can be hard to see this at first because we are so used to seeing the world as objects. We use that language every day, "my car broke down" when something goes loose in the engine. The engine doesn't have a singular expeirence about something going loose in it, just like the car doesn't have a singular experience about something going wrong in the engine, just like the traffic system doesn't have a singular experience about one car breaking down. A logic gate doesn't have a singular experience of the neurons flowing around it, and the CPU doesn't have such experience of one of its gates going up, a computer doesn't experience what the CPU is doing, and the internet doesn't experience what your computer is doing. This whole business of classifying "objects" into a hierarchical structure is just not getting us anywhere with consciousness, it's just panpsychism. Incoherent and meaningless.

Panpsychism gets into immediate trouble in defining what is the granularity in what sense "objects" metaphysically exist, for you do not have a conscious experience of what is happening to an individual neuron in your brain.

**So that's why consciousness could be defined as a "singular experience that occurs to a colony of things", and for that reason it should be seen as the emergent function of the colony; a function that the whole system has while none of its parts have it. Just like ice is not slippery because it is made of slippery atoms, but because friction is an emergent function of colonies of atoms. (IF that's the way your semantical mind chooses to see it)**

But I am sure that ice has not the experience of slipperyness.

Certainly not. Consciousness is just one instance of "emergent functions". Not all emergent functions are consciousness. Emergent function too is not something that metaphysically exists, but merely a method to classify/comprehend reality.

The important thing to understand is that world is full of systems that have a function which none of its parts have. The problem that especially panpsychists have is that they suppose if the brain is conscious, so then must all of its parts be. It is just like thinking atoms are metaphysically made of "matter" instead of understanding what we call matter is an emergent function of the elements of an atom. A large pile of electrons is not like sand, and fire is not made out of fire (contrary to the old belief :)

Careful

Sep6-06, 06:48 AM

DrChinese

Sep6-06, 07:35 AM

I don't see why, an observable could just be a coarse grained property and those are not necessarily all well defined at each moment in time (like temperature in a non equilibrium situation). But that is not the point I guess, you basically refuse to accept an extension of reality (way less crazier than string theory) to solve the paradox.

Careful

What extension are you proposing? Bell gave a specific definition (http://drchinese.com/images/BellVectorC.jpg), and it seems pretty reasonable to me. His definition seems like it could be a "course" grained property, at least the way I see it. For example: spin could be an emergent property rather than an intrinsic property, and still have a specific measurable value.

Careful

Sep6-06, 07:38 AM

What extension are you proposing? Bell gave a specific definition (http://drchinese.com/images/BellVectorC.jpg), and it seems pretty reasonable to me. His definition seems like it could be a "course" grained property, at least the way I see it. For example: spin could be an emergent property rather than an intrinsic property, and still have a specific measurable value.

Yes, that was the first part of my previous message (which was a reaction to your post 47), the second part of my message said that you might want to conceive that reality is more than what we straightforwardly deduce from measurement. I have given at least four examples how to do this on this thread, in post number 2 to be precise and there I still did not include the possibility that the future might influence the present (since it is not a strictly local theory).

Careful

AnssiH

Sep6-06, 08:35 AM

** Because even if we have labeled something as "central system", it doesn't mean this system experiences whatever occurs to one of its parts.**

Of course, but now you reason from your wish about what consciousness should be without showing that any reasonable theory explaining conscious experience needs to satisfy this criterion.

Satisfy the criterion of there existing a singular subjective experience over some system?

Only thing we know about consciousness is that we are experiencing something subjectively. Is it not completely incoherent to point to an arbitrary direction and say "surely that object is also experiencing whatever it is experiencing", already for the simple reason that every person will see a different object there. One will see a car, another one a tire, and yet another one a scratch on the side of the car.

To make it clearer how this object-oriented thinking is completely arbitrary is that we are only pointing at stable patterns. If you assert that a doughnut is conscious, you must understand that the hole of the doughnut is just as much a stable pattern and one might simply choose to see it as an object. Is the hole experiencing too just by the virtue of naming this stable pattern as a hole?

Is a wave of the ocean experiencing something, or is it the water-molecules that are bouncing up and down that are experiencing something? Or rather is a lake experiencing something, or is the north-end of the lake having a different experience from the south-end? What about the rivers connected to the lakes, or the whole lake-river system?

How can we every say that some object is metaphysically experiencing something? Is it not more proper to say there are only stable patterns, instead of metaphysical objects? Bear in mind, when I say it is wrong to see the world as if there are objects, I am not saying that the apple you are throwing up and down in your hand does not actually exist, I am merely saying that to comprehend the situation in form of "apple", "hand", "matter" and space", and their associated behaviours, is just the way we understand reality, but not actually the way the structure of the reality exists.

Object-oriented thinking has led us astray so many times before btw. Like the idea that space is something with identity where objects move and electromagnetism proagates (=aether). Right now spacetime too is an idea about something where every location has an identity and objects move from one location to next. But as long as we talk about, say, matter and space, how can we really say where the matter ends and space begins? There is no wall to an atom, there are only physical functions which keep herds of atoms stable. We could just as well choose to see it as if atoms are extended, and as such the size of their whole influence, not the size as derived from, say, the observed distance between two atoms of certain type, or the distance from where other particles seem to be deflected (for the deflection is caused by an emergent function of an atom). The matter of the fact is that atomic models are just arbitrary ways to understand how things work at that scale, they don't necessarily say what exists metaphysically.

(Apologies for my posts tending to be a bit long... Things keep coming into my mind at increasing pace... Like I said, I've thought about these things for quite a while now... I hope I can at least raise interesting thoughts on the issue :P )

There is no problem for me as far as I am aware of. Why would a self learning machine (and such things are being developped) not be an adequate substitute for a human being in a physical theory ? Pay attention: I am not saying a human being is a self learning machine, I just say that the difference (if any) is not important for physics.

Well I am saying a human being is a self-learning machine, or at least I approve of using that label completely (which doesn't mean all learning machines are conscious).

I haven't asserted at any point that we couldn't build a conscious machine, I've merely said we cannot understand the reason why it is conscious while we can tell what are the appropriate parts that need to be to put together. Like cavemen could create fire without understand what it was. I have outlined myself a broad outline of what to pay attention to when building a conscious machine, and I believe "On Intelligence" describes completely valid framework for conscious machine as well.

Well, you know, nobody has ever *tested* that right ?! :rolleyes: It is the same with quantum mechanics, since as far as we know, it works on such and such scale for a collection of particles, it suddenly needs to hold for all individual entities separately at all scales. And if I am allowed to guess, yes I think that the ultimate central unit is going to be very, very small.

The problem with asserting that the ultimate central unit is very very small (and incidentally very very simple) is that it would just mean we'd find a tiny dot inside the brain and by stimulating ONLY that we could cause all the sensations that we currently cause by stimulating some other parts of the brain. Basically it makes the whole complexity of the brain moot, as all the parts that seem to actually do the object recognition wouldn't actually do **** :) Maybe just modulate some signal at most, for some completely arbitrary reason.

Sure, it is possible that we will find it to be this way, but it is very very unlikely. Consciousness does not reside in the simplest of elements of the universe I don't think, it must be a product of cumulated complexity.

Plus, it seems apparent that to learn enough to become consciously aware (to assume such concepts as existence and self), it needs relatively large learning network. There just needs to be enough "storage space". Human neo-cortex is this kind of space, and we need large portions of it to store such a huge worldview as all of us do.

This conversation is going the wrong way : I guess you should define what consciousness *is*.

Well, I could probably think of tens of definitions, but all of them would be bound to be strongly colored by some particular way to view the world. I think the definition of singular experience over collection of "things" is still valid. I'm not the only one defining it this way btw, for example at "Being No One":
"...It is a wonderfully efficient two-way window that allows an organism to conceive of itself as a whole, and thereby to causally interact with its inner and outer environment in an entirely new, integrated and intelligent manner..."

What this means is basically that a colony becomes to behave as a coherent whole, and in doing so there is a new kind of evolutionary stability found for this colony (and we call such colonies "organisms" or "animals". Richard Dawkins talks a lot about how organisms actually are colonies having "come together" at some point during the evolution in Selfish Gene")

Of course this also has to be understood in completely darwinistic way. It doesn't mean that evolution has stroke some magic structure which suddenly made "free will" or something like that possible. It just means that things fell into such stable structures where the whole structure behaves for the stability of the whole structure (and in doing so finds itself from the future "gene pool"), instead of all of its parts behaving for the stability of themselves.

It is not in any way "given" that you experience everything that comes in from your senses, and that you experiencing making the decisions of moving your limbs and whatnot. This occurs only if there really exists a learning/prediction mechanism that sorts the reality out into semantical concepts in some sense.

As an interesting side note, by severing the corpus callum we can create a situation where each hemisphere of the brain is conceiving itself as one, basically creating two conscious experiences inside one person. That is why these person complain about their other half doing things on its own(Alien hand syndrome). It is the "linguistic hemisphere" of course that is doing the complaining. There are many interesting experiments related to this, such as the person being able to make simple logical decision, but not being able to *say* why he did the decision. :)

DrChinese

Sep6-06, 09:45 AM

Yes, that was the first part of my previous message (which was a reaction to your post 47), the second part of my message said that you might want to conceive that reality is more than what we straightforwardly deduce from measurement. I have given at least four examples how to do this on this thread, in post number 2 to be precise and there I still did not include the possibility that the future might influence the present (since it is not a strictly local theory).

Careful

You said in #2: "There are at least four well known local mechanisms which violate the ``logic'' in this paper : holography, polarizable media, negative ``probabilities'', predeterminsim. "

I am not sure what you mean about the others, but I think I understand your point about negative probabilities. I.e. that if one does not rule out negative probabilities, then realism is not violated. Is that an accurate summary of your comment?

If so, I would still say that most folks would not agree with that position... even if it is technically accurate. (Because that would be equivalent to throwing the baby out with the bathwater.) The point of the exercise was to exclude all of the local realistic scenarios - the local hidden variable scenarios anyway - in which a more complete "classical" specification of the system is possible. Clearly, a negative probability scenario wouldn't meet that criterion; nor would a scenario in which the future influences the past. Don't get me wrong: These may be viable scenarios, but they are not "realistic" per Bell.

AnssiH

Sep6-06, 09:55 AM

...another lethal objection against panpsychism is that the only case of subjective experience that we know of - our own - is not a case of us experiencing "the reality hitting our brain" at all. We are not aware of the electro-chemical activity inside the brain or nothing of that sort. We are merely aware of some pattern having been recognized as "X". In other words, we are not aware of the physical activity inside the brain, but rather of the "logical" conclusions that are made about reality (by to that physical activity in some logical sense).

When you are reading this, you are recognizing patterns as letters or full words or even multiple words at once. To the brain these are just electric patterns hitting different parts of the cortex as you move your eyes. When you listen someone talk, you become aware of what word was said, but not necessarily of the actual wave patterns that hit your ears or the pitch (unless you concentrate on these), or the electric patterns that hit your cortex. We have found single cells to fire in the brain when a person sees the face of Bill Clinton or Halle Berry, which just means that the high levels of cortical hierarchy has recognized some pattern as such and such object. This object is what we are conscious of, we are never conscious of the electric activity.

And when I talked about semantical worldview, that talk is all about how the concept of grandmother cells has to be understood not as if there are cells that metaphysically have some meaning when they are fired, but as the brain itself assuming the meanings of everything into a logical structure that is completely self-supporting.

Now if a panpsychists starts claiming that any case of any reaction of anything is a case of the object in question having a subjective experience, they should also explain why is it that we are not aware of the reality hitting our brain, but only of the semantical concepts that exist due to specific learning processes our brain goes through? (here you can also see justification to my claim that no learning system has a conscious experience unless it has made certain assumptions about its own existence)

"But when I'm just looking at the room around me, am I not aware of reality as it is?". Of course you are not. Things, or different waves of light don't have colour to themselves metaphysically. This is naive realism. When you are looking at the room around you, you are still only aware of the semantical concepts that you recognize, such as various shapes or objects like shadows or spots of light or whatnot. Even the sensation of colour is, as I explained earlier, a fully semantical concept. Recognizing your room visually is not different from recognizing a melody from a sound pressure pattern. In fact the cortex is largely plastic in that all the spatial/temporal patterns from all the senses are processed in similar fashion. The only reason they are subjectively experienced so differently is because of certain assumptions that exist in the worldview.

Now, a dualist or idealist would object at this point saying that I am still describing something that is basically an arbitrary physical process, albeit we could call it "learning process", so why should we expect a subjective experience to exist on such type of physical process all of a sudden? As a materialist I make the assumption that when there exists such logical recognition system which interprets sensory data with its open-ended worldview where the concept of "self" exists in certain logical sense (but to an extent in arbitrary physical sense), a conscious experience exists. Otherwise we could indeed imagine a society of zombies who don't have a conscious experience but who would nevertheless spend countless hours at messageboards arguing about consciousness and how their "selves" exists. Is this possible? I don't think so. At least it would be completely absurd. But funny.

I still cannot really pin down WHY is it that recognizing certain patterns as such and such logical concepts, and consequently recognizing some experience logically as "I experienced this and that" causes a subjective experience. And I assume this is because of what I said about our comprehension always being just an artificial expression of reality. And by comprehension I mean anything you can have an experience of. ANYTHING.

setAI

Sep6-06, 11:19 AM

from hitchhikers Guide to the Galaxy- on replacing Arthur Dent's biological brain with an electronic one:

Zaphod Beeblebrox: "you'd just have to program it to say What? and I don't understand and Where's the tea? — who'd know the difference?"

Arthur Dent: "I'd notice the difference!"

Frankie Mouse: "No you wouldn't, you'd be programmed not to."

Careful

Sep6-06, 12:01 PM

***
I am not sure what you mean about the others, but I think I understand your point about negative probabilities. I.e. that if one does not rule out negative probabilities, then realism is not violated. Is that an accurate summary of your comment? ***

Read F SELLERI, chapter 5 ! How many times do I have to repeat that. :grumpy:

**
If so, I would still say that most folks would not agree with that position... even if it is technically accurate. (Because that would be equivalent to throwing the baby out with the bathwater.) ***

No, it is not, there is no baby. The only thing Bell is useful for, is to point out to local realists that they will have to come up with a nontrivial notion of reality.

**
The point of the exercise was to exclude all of the local realistic scenarios - the local hidden variable scenarios anyway - in which a more complete "classical" specification of the system is possible. **

Right, in that sense Bell's exercise was very limited and has no severe implications whatsoever for local realism as pointed out before.

Careful

DrChinese

Sep6-06, 03:07 PM

Read F SELLERI, chapter 5 ! How many times do I have to repeat that. :grumpy:

Do you mean:

Selleri, F., Quantum Mechanics Versus Local Realism: The Einstein-Podolsky-Rosen Paradox (Plenum Press, New York, 1998).

If something he said is identical to your opinion, I might be interested in the quote if it relevant. (I do not have this particular material.)

As best I can determine, you are saying that Bell's realism is not meaningful; and therefore his theorem is of limited applicability.

P.S. Might I kindly suggest that you consider using the quote function when replying? It would make it easier to distinguish your comments...

Sep6-06, 05:43 PM

So again, I return to the mathematical formalism (http://drchinese.com/images/BellVectorC.jpg) of Bell to serve as a specific definition.

In my view: The cited ''mathematical formalism'' provides a specific definition of the realism assumption used by Bell.

Therefore: Experiments which breach Bell's formalism involve realistic entities which are outside Bell's purview.

Then: In that many experiments breach Bell's inequality, Bell's ''realism'' is of a limited kind [... one that might be termed ''naive realism'' ... one commonly associated with the ''doctrine of faithful measurement'' ... ie, the doctrine that a ''measurement'' always reveals a ''pre-existing pre-measurement property''].

Conclusion: Many real objects (eg, photons and electrons) breach Bell's realism assumption. That is: Bellian inequalities are breached by both classical and quantum experiments because these objects lie outside the set of objects embraced by the limited realism in the cited formalism. wm

Chaos' lil bro Order

Sep6-06, 06:19 PM

'It is pretty obvious that when we have a conscious experience of anything (or rather "when there exists a conscious experience)", we don't actually experience reality itself, but we experience the artificial model of reality built by our brain. We can literally only understand an artificial model about these artificial models; this understanding too is based on huge amount of completely semantical concepts and arbitrary assumptions.'

This 'artificial reality' as you call it, is not really artificial at all. Its the tiny slice of the Universe than we can biologically sense. As our senses improve over time due to technological advancements, we start to see a larger and larger piece of the pie you may call the Universe or 'reality' if you prefer. If an alien civilization exists that has 8 senses, our 5 and 3 additional exotic senses, would its perception of reality also be called 'artificial' simply because its viewing reality through consciousness? Or perhaps you would call it less artificial because it sees a bigger slice of reality with its extra 3 exotic senses.

I suspect your view may be that consciousness is some kind of filter that disallows the true reality to be perceived. If this is the case, I think it is a good idea to ponder about where the disconnect between 'the true reality' and 'artificial reality' lies. To my mind the pathway between the true reality and artificial reality has 3 components, the senses, the consciousness and the 'true reality particles', for lack of a better word. So then, is the problem that our senses don't take a correct snapshot of the 'true reality particles', or is it that our consciousness cannot correctly grasp the information that our senses gather from the 'true reality particles'? Perhaps both right, who knows.

In a nutshell my view is that no description of 'true reality' is 'artificial' because no lifeform with the gift of consciousness has a preferred frame of referrence with which to act as the de facto standard. So sure, our description of the 'true reality' is incomplete (and thank god or else we'd have nothing else to learn!), yet I think the slice of reality pie that we have managed to cleave off so far is 100% natural, with no 'artificial' ingredients. And quite frankly it is delicious.

AnssiH

Sep7-06, 03:36 AM

This 'artificial reality' as you call it, is not really artificial at all. Its the tiny slice of the Universe than we can biologically sense. As our senses improve over time due to technological advancements, we start to see a larger and larger piece of the pie you may call the Universe or 'reality' if you prefer. If an alien civilization exists that has 8 senses, our 5 and 3 additional exotic senses, would its perception of reality also be called 'artificial' simply because its viewing reality through consciousness? Or perhaps you would call it less artificial because it sees a bigger slice of reality with its extra 3 exotic senses.

I suspect your view may be that consciousness is some kind of filter that disallows the true reality to be perceived. If this is the case, I think it is a good idea to ponder about where the disconnect between 'the true reality' and 'artificial reality' lies.

No it's not the case :)
It's not about what we can sense with our natural senses, but about how we classify/understand the sensory data. We could plug any arbitrary number of artificial sensory systems into the cortex and so have a qualia experience of, say, X-rays or thermal camera or anything like that, and yet the comprehension of any sensory data would not be the metaphysical reality of that data, but some logical conclusions about what "objects" exists and how they behave with each others.

Let's say you are feeling a coin in your hand (and you actually have to move it around in your hand to recognize it; brain needs not only spatial but also the temporal aspect of a pattern to recognize anything) . The sensory data pouring into your brain is in constant flux in the cortex. As the coin moves in your hand it causes different nerve cells of your hand to fire, and they connect to different parts of cortex. Yet there is at all the times a subjective sense of "you" experiencing the coin, not a sense of electricity rushing around in the cortex.

The pattern recognition that occurs in the cortex is able to judge all this against something you've experienced before, and assume simply that it is "a coin" in your hand (i.e. if only in your worldview there exists some assumptions about coins and such things). And not only that, there exists other concepts about reality in your worldview, such as the roundness and the flatness, and the texture, weight and temperature of the object, all semantical assumptions about "things" or "concepts" that exist.

The only difference between so-called naive realism and "accurate" realism is that the latter one breaks the world down into simpler functions or concepts, but there is no fundamental difference in how we understand things.

Note especially how at all times you can only be aware of the logical side of things, not so much about the reality of things flowing in your brain or how the coin could be in reality. Note how even classifying this experience in the form of objects and their relationships is just our method of "understanding". It is probably the only method with which subjective experience can come to exist, but it is by no means a way to understand how reality really is. I struggle to explain in detail why this is so because I can only use semantical concepts to talk about it. The understanding of why this is so comes from understanding how this method of understanding is merely an arbitrary way to predict the environment (to avoid dangers in novel situations).

Note how even the experience of just seeing your room is about understanding many many concepts about reality around you. Your brain can recognize such high-level concepts as "my room" from the sensory data, or it can recognize many many low-level concepts from within the room. But all of these are just concepts, i.e. assumptions or ideas about reality. In other words, you are merely aware of the mental model or the "simulation of reality" running in your head, which is necessarily expressed in form of certain concepts, instead of in the form of how reality is. Much like in a computer simulation a physical storm is expressed not in the form of how the real storm is, but in form of numbers or bits.

And at last, consider the reality of colours. If the whole world was red, there would be no such concept as "colours" in our understanding. It would be impossible to understand what are colours, until we saw for the first time something that is "NOT red". For the first time there would be a juxtaposition for red, so to understand what does red mean. However, to assume that red things really look "red" in reality is naive realism; they don't. Things don't have colours per se, the only difference between red and green is the difference in the electric signal that is coming in to the cortex. With this difference the brain classifies red and green as different things into the worldview, and the subjective experience of how they look like can be arbitrary, as long as they are experienced differently

These logical conclusions about reality can be extrapolated to all senses and all things we have any understanding of, including "self", and if you spend some time thinking about it, I think it will blow your mind to realize how different reality really can be from how we understand it to exist.

Careful

Sep7-06, 06:28 AM

Do you mean:

Selleri, F., Quantum Mechanics Versus Local Realism: The Einstein-Podolsky-Rosen Paradox (Plenum Press, New York, 1998).

If something he said is identical to your opinion, I might be interested in the quote if it relevant. (I do not have this particular material.)

As best I can determine, you are saying that Bell's realism is not meaningful; and therefore his theorem is of limited applicability.

P.S. Might I kindly suggest that you consider using the quote function when replying? It would make it easier to distinguish your comments...
Why would I point you to an irrelevant source ? :confused: It is not that I say my opinion is identical to Selleri's, just that I see possibilities in the solutions presented in this chapter. Science is not about opinions but facts, and we don't have unfortunately enough of them, even for pretty basic things. That is why there are so many ``opinions''.

Careful

Chaos' lil bro Order

Sep7-06, 10:45 PM

And at last, consider the reality of colours. If the whole world was red, there would be no such concept as "colours" in our understanding. It would be impossible to understand what are colours, until we saw for the first time something that is "NOT red". For the first time there would be a juxtaposition for red, so to understand what does red mean. However, to assume that red things really look "red" in reality is naive realism; they don't. Things don't have colours per se, the only difference between red and green is the difference in the electric signal that is coming in to the cortex. With this difference the brain classifies red and green as different things into the worldview, and the subjective experience of how they look like can be arbitrary, as long as they are experienced differently

.

Well certainly I agree with this paragraph of your post. I see no reason to argue about which words we use to give semantic meaning to specific concepts such as 'red' colors. Any word will do fine, so long as it confines our observation of this 'red' color to a singular experience. By singular experience I mean that we can define a ~1eV photon as 'red' and a
~1.5eV photon as 'blue'. Of course we can change the names around, but so long as both names identify two seperate experiences, they suffice perfectly. I think this sensed version of reality is identical to any observer independent reality. In both cases two photons exist, period. The properties of the photons do not change.

There is only one reality. Many perspectives. But ONE reality. Our sensory perspective is incomplete in its full detailing of this reality, yet still there is only one reality. You see, we cannot know how full our picture of reality is at any given point because history has taught us that we make new discoveries everyday. Thus our picture is constantly increasing, but never complete. Its like the observable horizon of the Universe, every day as the light cone from the region on the fringes of our Universe reaches our telescopes, new Quasars seem to 'pop' into reality. But in reality, these Quasars always existed, its just that now we can perceive them.

From your post, I gathered that you think the disconnect is between the brain and the sensory input... I really cannot be convinced of this so far, can you prove this to me somehow?

P.S. How might a creature who knew every phenomena of space and time describe the universe? Would he give an inaccurate picture of the universe simply because he defined it in words?

MeJennifer

Sep7-06, 11:16 PM

There is only one reality. Many perspectives. But ONE reality.
I disagree that this statement must be unquestionably true.

For example in the theory of relativity we cannot determine one reality, there are only perspectives. So how can we assert there is one reality?

I am not saying you are wrong, but it seems you state something you can not possibly prove and appears to be a statement of belief.

AnssiH

Sep8-06, 05:12 AM

Well certainly I agree with this paragraph of your post. I see no reason to argue about which words we use to give semantic meaning to specific concepts such as 'red' colors. Any word will do fine, so long as it confines our observation of this 'red' color to a singular experience. By singular experience I mean that we can define a ~1eV photon as 'red' and a
~1.5eV photon as 'blue'. Of course we can change the names around, but so long as both names identify two seperate experiences, they suffice perfectly. I think this sensed version of reality is identical to any observer independent reality. In both cases two photons exist, period. The properties of the photons do not change.

Yeah, the observation of photons is caused by something that exists, but the metaphysical reality of the photons is based on certain semantical assumptions about reality, and we don't know what the metaphysical reality of photons is. So I'm not saying that when we observe photons there is in fact "nothing there and our observation is just an illusion" or anything of that sort. I'm merely saying that we can never find out what are "the things that metaphysically exist", we can only postulate certain fundamentals so to come up with a description of a system that produces everything we observe, but there are bound to be an arbitrary number of radically different postulates about what exists. There already are many such postulates, albeit we can say some of them explain much less than the others. Like fundamentally expanding spacetime or electrons as spherical standing waves and what have you. Regardless of if you find these ideas moronic or not, they are good excercises in thinking about the philosophical aspects of metaphysics. For example:
http://www.estfound.org/philosophical.htm
Einstein's commentary at the page, about the completeness of general relativity is a sign of very healthy philosophy, and it applies to any scientific model.

There is only one reality. Many perspectives. But ONE reality.

Exactly. This is the fundamental notion of materialism. And I'm a materialist too. (And that's right Jennifer, it only applies to materialistic paradigm. Which is, after all is said and done, a statement of belief. In fact it is because of the way we understand reality that we can only make statements of belief; any statement is true only in so far that certain other statements in our worldview are true, but all of them are also assumptions. A self-supporting worldview is how we work, like I said before)

From your post, I gathered that you think the disconnect is between the brain and the sensory input... I really cannot be convinced of this so far, can you prove this to me somehow?

That's not what I'm trying to say. What I'm saying is referring to the way we understand, not to the way our senses measure reality.

Perhaps I better try this by asking a question; What is an object? The world seems to contain many individual things, like "apples". We recognize an apple by their familiar pattern hitting the cortex. Furthermore, apples are made of many other objects, like the peel and seeds, which are furthermore made of even simpler parts, etc... Also the apple is a part of larger objects, like an apple tree, or an apple farm.

But what really is in a metaphysical sense, an object? Is an apple a single entity? Or the apple farm? Is the water in a bowl an object? What about a shadow? What constitutes an identity of an object? What does it even mean to say that there exists objects? Is photon an object?

Thinking about these issues, it should become apparent that we classify reality into objects by the properties of some stable patterns that exist, but there is no sense in postulating that world really exists in forms of entities that have relationships between each others. What we call "identity" is more accurately just a case of "stability". World just is one big dynamic "thing" where some patterns are stable for longer periods of time than others, but this whole business of classifying such patterns into "objects" for the purpose of being able to assume certain persistent behaviour to such "objects", is simply the way reality is necessarily expressed in the brain. This is a physical necessity because this is the only way to actually predict something that has not yet happened. And this is why comprehending reality "as it is" is beyond thought.

P.S. How might a creature who knew every phenomena of space and time describe the universe? Would he give an inaccurate picture of the universe simply because he defined it in words?

Well, the whole assertion of "world is made of individual entities" is meaningless. Which doesn't mean "we are all the same" is correct either. We can probably one day make arbitrary number of arbitrarily accurate descriptions of reality, but there will be no way of choosing which one must be right, because they are necessarily descriptions of what "things" exist. So also the creature describing everything that ever happened would necessarily describe it in terms of entities and their relationships.

Even the assertion "I ate breakfast this morning" is wrong because I am asserting I am something with identity, that there is a magical "self" inside me that was there this morning and is still there now. There is no such identity to self, I am only a stable pattern and since I can be defined only by my cumulated worldview - which has changed since this morning - I am in fact a different being now than I was this morning. I could say that I am "changing into different being from every moment to the next", only this too is an assertion about what exists ("one being" and "moments"), and it is basically also incorrect assertion.

It is very important to understand these issues with QM, so to start looking at the world in form of "stable patterns" or "stable systems" instead of "objects". This is important when asking "what is a photon" or if the idea of particle-like existence of energy in the space between atoms is given at all. When someone asks "how do we know there are photons?", it is remarkably unthoughtful to say "because we have measured them". We have not measured a photon, we have just observed a stable pattern or behaviour in some system, and made certain assumptions about the metaphysical reality of that behaviour (assumed that it was caused by a photon). No one has ever seen a photon, and no one ever will. One can only make certain measurements and believe the results were caused by something we call "a photon". (And this says nothing about how accurate or inaccurate our concept of photons is, or how much it explains)

We make certain assumptions about what things exist (and how), and if our ideas about what exists are too inaccurate, we will "observe obscure behaviour". This is true for any system. I'm merely taking this one step further and saying that we can never know for sure which things "truly" exist. (I think we can make deterministic interpretations. In fact we can probably make quite a few different sorts of deterministic interpretations, just by postulating different fundamentals to exist. As a materialist I also believe world really is deterministic, btw)

Chaos' lil bro Order

Sep9-06, 01:33 AM

I disagree that this statement must be unquestionably true.

For example in the theory of relativity we cannot determine one reality, there are only perspectives. So how can we assert there is one reality?

I am not saying you are wrong, but it seems you state something you can not possibly prove and appears to be a statement of belief.

Don't you see what I am getting at here in this post? There is only one underlying reality. This reality, very fortunately for us, can be objectively examined and its properties solved for by Math. Math is the universal language. Even if there were a dozen alien civilizations in the universe with a completely different set of senses from one another and their brains interpreted the underlying reality completely differently. These dozen alien civilizations could communicate what mathematical laws in the universe they have solved for so far.

selfAdjoint

Sep9-06, 05:55 AM

Don't you see what I am getting at here in this post? There is only one underlying reality. This reality, very fortunately for us, can be objectively examined and its properties solved for by Math. Math is the universal language. Even if there were a dozen alien civilizations in the universe with a completely different set of senses from one another and their brains interpreted the underlying reality completely differently. These dozen alien civilizations could communicate what mathematical laws in the universe they have solved for so far.

Whatyou are getting at is that you ASSERT there is "one underlying reality". Where did you get this? What is your EVIDENCE for it? Is it your religion?

Chaos' lil bro Order

Sep11-06, 12:58 AM

Do you know of any others selfAdjoint?

Chaos' lil bro Order

Sep11-06, 10:08 PM

I repeat. Do you know of any other realities other than the one we live in? I think the burden of proof lies on those who claim there is an underlying reality beyond our sensory perceptions. In fact that view is unattenable and unfalsifiable and does not sound like good science to me. My view in this matter is not fixed and NO it is not my religion, nor do I have a religion, nor have I ever had a religion. I'm completely open to being convinced that there is an underlying reality beyond our sensory perceptions, but as I say, I think this impossible to prove, even in theory.
Interestingly, even the definitions of 'reality' do not agree with eachother. Some seem to say reality is observer-independent (underlying reality), while others say reality is a collection of your experiences. :smile: Its no wonder we can't agree then! haha.

Dictionary.com - Reality

'all of your experiences that determine how things appear to you;'

'The totality of all things possessing actuality, existence, or essence'

Philosophy. a. 'something that exists independently of ideas concerning it. '
b. 'something that exists independently of all other things and from which all other things derive.'

Hurkyl

Sep11-06, 10:45 PM

I think the burden of proof lies on those who claim there is
The burden of proof lies with the person doing the claiming. Since you have asserted there is "one underlying reality", you have a burden to prove your claim.

If selfAdjoint had claimed there were multiple underlying realities, he would also have a burden to prove that claim. As it is, though, he's simply prodding you for making unsubstantiated assertions.

Chaos' lil bro Order

Sep11-06, 11:10 PM

The burden of proof lies with the person doing the claiming. Since you have asserted there is "one underlying reality", you have a burden to prove your claim.

If selfAdjoint had claimed there were multiple underlying realities, he would also have a burden to prove that claim. As it is, though, he's simply prodding you for making unsubstantiated assertions.

Wrong. I am simply saying that if we agree that our sensory perceptions neccessarily bias our observations of any supposed 'underlying reality'. Then we can never know if there is an 'underlying reality' by definition. For how else can we ever observe this 'underlying reality' without our senses? We cannot. Therefore there is only the reality of sensory perception.

If you still do not understand me (and at this point I don't see how you possibly could not), try imagining this simple example:
Take a tennis ball and hide it under a box. Call your wife in the room and ask her to tell you what is inside the box. You will be amazed to see that she cannot tell you what's inside the box. Do you know why? Because none of her senses can penetrate the box, it is impossible for her to know the contents. Now call your son into the room and ask him the same question and he will also not be able to answer what is inside the box. Now you leave the room and tell your wife and son to discuss what the possible contents of the box are. Given sufficient time, they will come up with every object imaginable that could fit the dimensional constraints of the box, but all of their guesses will be equally wrong and equally correct since they have no way to falsify them. Now imagaine that this box's size is infinite. Your wife and son will exhaust every possible object they can think of and still be no further to a solution as to what the box's contents are.
To finalize my construction, I put forth to the reader that arguing whether there even is an object inside the box is futile and unknowable. But what can be agreed upon is that there is a box that can be sensed by both observers. Therefore the only reality that can be known to your wife and son and anyone else really, is that there is a box, in which there may or may not be an object inside. Barring the notion that your wife and son develop a new sense like X-ray vision, their reality-horizon can only ever be that which they can sensorily perceive, pure and simple.

Maybe you can tell me what is beyond the Universe's observable horizon please? Then you can also tell me what is beyond a human's reality-horizon as well please?

I am open to speculation, but alas, the only truth we can agree upon about reality or anything else for that matter, is what is true at this very moment.

AnssiH

Sep12-06, 08:44 AM

Well I think the last 6 posts are a good showcase how different our semantical concepts can be. Chaos clearly is using "reality" to simply refer to "everything that exists", whatever that may be. Whereas others may consider reality to mean "things that we can have information about", i.e. things that interact one way or another with the stuff we are made of, directly or indirectly (perhaps there exists other complex structures and systems that just don't interact with what we call matter at all), and yet others may consider physical reality to be one reality and some sort of spiritual reality to be another reality. Some make distiction between "objective reality" and "subjective reality", and some think only the latter one exists.

I think this same sort of confusion is evident it all kinds of arguments about whether it was "reality" that began with "the big bang".

So here it is also visible how our sense of reality is based on certain assumptions about what meaning certain concepts have and what things may exist and in what ways. When you are making statements about just what is "reality", it becomes pretty clear how impossible it is to get the hang of it with semantical concepts. Even if we can make everybody understand these concepts in the same manner, who is to say that is metaphysically "the correct way" to understand reality?

The statement that we are all part of and sharing our experiences in one single objective universe at the same time (and so on), that's a statement of belief that belongs to materialistic paradigm. Hmmm, well a materialist usually considers spacetime to be true also, so that makes it all a bit convoluted, as then we are not in fact experiencing things "at the same time" in any sense at all... :I (And here's the reason I would like to be careful with assertions about the metaphysical existence of spacetime)

RandallB

Sep12-06, 09:47 AM

The burden of proof lies with the person doing the claiming. Since you have asserted there is "one underlying reality", you have a burden to prove your claim.I disagree; all logic must come from a beginning foundation and belief.
Logic tells us that there may be many views of reality QM, BM, QED, SED etc. that may all give accurate predictions as an analogy of reality. But no one can claim to be CORRECT as in COMPLETE until it can demonstrate a complete explanation of how the others produced accurate results but within there own more complete detail of the correct one reality. Thus making it clear where, when and why the other views produce the accurate results they give.

What is the foundation of the logic the can bring this conclusion. The same foundation that gives you the most fundamental basis for even asking for a proof.

Before you can ask you must "be".
If you accept the foundational logic that “you think therefore you are”
This provides sufficient fundament logic to build on to come to the conclusion there is only one reality.
If you do not agree that “you think therefore you are” then you need to offer some proof that you exist before you can even ask the question. Preferably a proof that does not lead to the rules of logic we know.

setAI

Sep12-06, 11:19 AM

I repeat. Do you know of any other realities other than the one we live in?

not only are there other 'realities'- but we now use them to perform computations that would be impossible in just one reality

"there are indeed other, equally real, versions of you in other universes, who chose differently and are now enduring the consequences. Why do I believe this? Mainly because I believe quantum mechanics... Furthermore, the universes affect each other. Though the effects are minute, they are detectable in carefully designed experiments... When a quantum computer solves a problem by dividing it into more sub-problems than there are atoms in the universe, and then solving each sub-problem, it will PROVE to us that those sub-problems were solved somewhere - but not in our universe, for there isn't enough room here. What more do you need to persuade you that other universes exist? " -David Deutsch

AnssiH

Sep12-06, 11:33 AM

not only are there other 'realities'- but we now use them to perform computations that would be impossible in just one reality

"there are indeed other, equally real, versions of you in other universes, who chose differently and are now enduring the consequences. Why do I believe this? Mainly because I believe quantum mechanics... Furthermore, the universes affect each other. Though the effects are minute, they are detectable in carefully designed experiments... When a quantum computer solves a problem by dividing it into more sub-problems than there are atoms in the universe, and then solving each sub-problem, it will PROVE to us that those sub-problems were solved somewhere - but not in our universe, for there isn't enough room here. What more do you need to persuade you that other universes exist? " -David Deutsch

...like I said, we all use the world "reality" to mean so many different things... :P
And btw, why is MWI becoming into some sort of religion all over the place? There must be something very tempting to a model of reality that implies there's more to reality than we readily perceive... After all, this is what tempts people to believe in any religion :)
Oh boy, next I'm going to hear how MWI "cannot be proven wrong" and how it's "the only possibility".

Hurkyl

Sep12-06, 02:35 PM

I disagree; all logic must come from a beginning foundation and belief...
I'm confused -- I don't see anything in your post that talks about burdens of proof. In fact, I can't figure out what your point is at all.

kvantti

Sep12-06, 02:36 PM

...like I said, we all use the world "reality" to mean so many different things... :P
And btw, why is MWI becoming into some sort of religion all over the place? There must be something very tempting to a model of reality that implies there's more to reality than we readily perceive... After all, this is what tempts people to believe in any religion :)
Oh boy, next I'm going to hear how MWI "cannot be proven wrong" and how it's "the only possibility".

Well, here is a challenge for you (and for everyone who doesn't believe in the MWI) from Deutsch (as presented in his book The Fabric of Reality):

Explain where the calculations made by a quantum computer are performed when it solves the sub-problems associated with a single problem. Eg. when factoring a 250-number digit using the Shor's algorithm (http://en.wikipedia.org/wiki/Shor's_algorithm), the number of sub-problems is about 10^500 (the number of particles in the universe is about 10^80).
And yet, a quantum computer solves all the sub-problems at the same time. So how can it solve 10^500 problems during only one calculation, if we have only one computer in only one universe?

(It would take classical computer 10^500 times the time of a quantum computer to perform the same operation)

And for the question why the MWI has become "some sort of religion": it gives a coherent, local and deterministic description of reality and in my point of view, it would be illogical that there would be only one universe. Didn't you think that there are "other dimensions" when you were a kid? :rolleyes:

setAI

Sep12-06, 02:39 PM

A few years ago, BBC Horizon did a documentary on time travel in which you explained the parallel universes theory and suggested that there was ‘hard evidence’ for it. Well, it is a controversial theory and is accepted only by a minority of physicists, as you yourself acknowledge in your book. Why do you think there is such a strong reaction to this theory in the scientific community? And how do you reply to their criticism?

David Deutsch: I must confess that I am at a loss to understand this sociological phenomenon, the phenomenon of the slowness with which the many universes interpretation has been accepted over the years. I am aware of certain processes and events that have contributed to it. For instance Niels Bohr, who was the inventor of the Copenhagen interpretation, had a very profound influence over a generation of physicists and one must remember that physics was a much smaller field in those days. So, the influence of a single person, especially such a powerful personality as Niels Bohr, could make itself felt much more than it would be today. So that is one thing – that Niels Bohr’s influence educated two generations of physicists to make certain philosophical moves of the form "we must not ask such and such a question." Or, "a particle can be a wave and a wave can be a particle," became a sort of mantra and if one questioned it one was accused of not understanding the theory fully. Another thing is that quantum theory happened to arise in the heyday of the logical positivists. Many physicists – perplexed by the prevailing interpretations of quantum physics – realised that they could do their day-to-day job without ever addressing that issue, and then along came a philosophy which said that this day-to-day job was, as a matter of logic, all that there is in physics. This is a very dangerous and stultifying approach to science but many physicists took it and it is a very popular view within physics even to this day. Nobody will laugh at you if, in reply to the question "are there really parallel universes or not?", you answer "that is a meaningless question; all that matters is the shapes of the traces in the bubble chamber, that is all that actually exists." Whereas philosophers have slowly realised that that is absurd, physicists still adopt it as a way out. It is certainly no more than ten percent, or probably fewer, of physicists talking many universes language. But it is heartening that the ones who do tend to be the ones working in fields where that question is significant, which are quantum cosmology and quantum theory of computation. By no means all, even in those fields, but those are the strongholds of the many-worlds interpretation. Those also tend to be the physicists who have thought most about that issue. But why it has taken so long, why there is such resistance, and why people feel so strongly about this issue, I do not fully understand.

Hurkyl

Sep12-06, 02:40 PM

kvantti, setAI: people have already responded to your assertions many times. If you don't want to be crackpots, you would do well to stop mindlessly repeating them without any regard to the received criticism. :rolleyes:

Explain where the calculations made by a quantum computer are performed when it solves the sub-problems associated with a single problem.
In the quantum computer: where else?

In fact, when I learned quantum computation in one of my classes, we learned it from a solidly Copenhagenist viewpoint.

setAI

Sep12-06, 02:56 PM

kvantti, setAI: people have already responded to your assertions many times. If you don't want to be crackpots, you would do well to stop mindlessly repeating them without any regard to the received criticism. :rolleyes:

this is the irony- the MWI IS now the mainstream/orthodox/dominant/whatever interpretation of QM- as acknowledged by virtually every major and minor professional physicist on the planet [minus a few slow-pokes in the USA and Penrose on odd-numbered-days]

it is rather shocking that even some of the moderators on this forum are actually going against what is considered the most rigorous empirically verified concept in physics- and they are mis-representing it here as something less- even crankish?!?!?!

the so-called 'received criticism" was a joke- totally refuting facts- and rejecting peer-reviewed science that is the basis for the most successful technology in human history!

you are firmly representing the crackpot view here- not us- I have 100 years of empirical QM data and the opinions of nearly every professional physicist in the world to back it up- you have a head-in-the-sand interpretation that tells you to "shut up and calculate"- how can you possibly think you represent the interests of real science here?

how do you reconcile your "crackpot" comment against the fact that the MWI [and similar interpretations] is now the only interpretation that professional physicists accept? what next? are you guys going to try and convince people that Darwinian Evolution or Plate Tectonics are crackpot pseudoscience as well? and that is not just a cheap shot- MWI has as much if not MORE experimental support than Natural Selection or PT- in fact it is the most empirically supported idea in physics at this time in history

of course the MWI is not complete- not the whole answer- but it is BY DEFINITION the only actual interpretation we have- as DD mentioned in the above interview- Copenhagen/Hidden Variable/ etc 'interpretations' are illogical and absurd- there aren't interpretations AT ALL- by definition MWI is the only version of QM that is a viable version of the theory-

ignorance is not an alternative to understanding! just becasue a handful of stick-in-the-muds haven't bothered to pick-up a physics journal for the last 6 years doesn't mean those of us who have should have to play nice and pretend that there are still other interpretations of QM worth discussing-

this is a moderated forum that discusses peer-reviewed QM- thanks to DD's work right now that is MWI and only MWI [follow the funding]

setAI

Sep12-06, 03:39 PM

And for the question why the MWI has become "some sort of religion": it gives a coherent, local and deterministic description of reality and in my point of view, it would be illogical that there would be only one universe.

quite illogical- I never understood the 'single universe' conjecture- as it requires something like God: all empiricality shows that the world possesses causality and laws- and any such causal system has transfinite possible states and histories- for our universe to be the only one would require some process that neatly prevents/destroys/cancels out all other possibilities ins space AND time and only allows this one- this would be the grandest epicycle of all- and totally renders any theory assuming one universe as utterly moot and unphysical [or at least very limited ]

which is why as technology and theory advance more and more theories have a fundamental multiverse structure- QM/ Inflation/ M-Theory/ LQG all posit a phase space of possible structures in which the observed world is only a small region-

some form of multiverse is a self-evident fact unless you believe in a filtering deity- the MWI is the only version of QM that corroborates the physical necessity of the multiverse

RandallB

Sep12-06, 04:14 PM

I'm confused -- I don't see anything in your post that talks about burdens of proof. In fact, I can't figure out what your point is at all.Not meeting the Burden is stuff like:
“When a quantum computer solves a problem ………..it will PROVE
What more do you need to persuade you that other universes exist?" -David Deutsch

He didn’t say it had been proven; just that when and IF they actually make a true Q-C it will, (IMO they won’t). That is way short of any reasonable logic, and provides no proof for MWI or multiple realities.

All I’m saying is well founded logic (They teach it in University) IMO is sufficient to prove there must only be one complete reality.
If not, then Logic it self is wrong! - back to the beginning where you claim “I think therefore I am”.
If logic cannot carry the burden to prove the claim of one reality,
Then no one can use Logic to claim there own existence to be able to even question the claim or demand addition proof.

Just simple logic - works for a simple kind of guy like me

setAI

Sep12-06, 04:26 PM

Not meeting the Burden is stuff like:
“When a quantum computer solves a problem ………..it will PROVE
What more do you need to persuade you that other universes exist?" -David Deutsch

He didn’t say it had been proven; just that when and IF they actually make a true Q-C it will, (IMO they won’t). he said this will prove it to those who don't currently accept it- actual professional physicists have accepted the proof of MWI since it was demonstrated that seperate computations on universal CNOT gates could be performed in parallel on BOTH possible paths of a photon in the two-slit experiment simultaneously-

All I’m saying is well founded logic (They teach it in University) IMO is sufficient to prove there must only be one complete reality.

Just simple logic - works for a simple kind of guy like me

so tell me what do you name the God/filter that murders all other possible outcomes of a physical processes in which all possible outcomes are observed?

RandallB

Sep12-06, 05:15 PM

he said this will prove it to those who don't currently accept it- actual professional physicists have accepted the proof of MWI since it was demonstrated that seperate computations on universal CNOT gates could be performed in parallel on BOTH possible paths of a photon in the two-slit experiment simultaneously-

so tell me what do you name the God/filter that murders all other possible outcomes of a physical processes in which all possible outcomes are observed?Now there is one that " I can't figure out what your point is at all."
Care to prove you exist so I'll know you are real & not something from an unreal reality.

Hurkyl

Sep12-06, 06:10 PM

this is the irony- the MWI IS now the mainstream/orthodox/dominant/whatever interpretation of QM- as acknowledged by virtually every major and minor professional physicist on the planet [minus a few slow-pokes in the USA and Penrose on odd-numbered-days]
It would be interesting to see the study that determined that. :rolleyes: But this is a digression...

I have 100 years of empirical QM data
You just don't seem to understand what the criticism is. :frown: Copenhagen has the exact same 100 years of empirical QM data supporting it too. And if the Bohm interpretation ever figures out how to work in the relativistic setting, then it will too.

The whole problem is that you present a piece of evidence which is predicted by the Copenhagen interpretation (and Bohm too, I think), and somehow conclude that it proves MWI is the only tenable interpretation.

And, in your lashing out at any criticism, you seem to have missed the fact that I actually like the MWI interpretation, and find it the most natural of the "popular" interpretations. (Though I think I will change my mind once we can consider the relational interpretation popular) :wink:

which is why as technology and theory advance more and more theories have a fundamental multiverse structure- QM/ Inflation/ M-Theory/ LQG all posit a phase space of possible structures in which the observed world is only a small region-
Pretty much every scientific theory permits a very large space of configurations that will never be realized by our observed world...

some form of multiverse is a self-evident fact
Are you sure you meant "self-evident"? I thought that, even to you, it is only evident because you find it a natural consequence of QM.

IF they actually make a true Q-C it will, (IMO they won’t).
They already have. They just haven't made a "big" one.

Now there is one that " I can't figure out what your point is at all."
Care to prove you exist so I'll know you are real & not something from an unreal reality.
This is an ad hominem fallacy. The argument stands or falls on its own merit. It doesn't matter if it originated from an existing speaker.

Chaos' lil bro Order

Sep12-06, 06:38 PM

Careful

Sep13-06, 05:54 AM

** quote Hurkyl
And, in your lashing out at any criticism, you seem to have missed the fact that I actually like the MWI interpretation, and find it the most natural of the "popular" interpretations. (Though I think I will change my mind once we can consider the relational interpretation popular) :wink:
**

I must congratulate you for the ability to decide upon these fundamental matters according to the latest fashion in town. Perhaps, we should organize miss elections about these issues in the same way as this is done on some other forum - that would constitute the ultimate downfall of science.

Careful

Hurkyl

Sep13-06, 07:10 AM

I must congratulate you for the ability to decide upon these fundamental matters according to the latest fashion in town. Perhaps, we should organize miss elections about these issues in the same way as this is done on some other forum - that would constitute the ultimate downfall of science.
Huh? :confused: I mean to say that I think RQM > MWI > Copenhagen > Bohm.

kvantti

Sep13-06, 08:18 AM

kvantti, setAI: people have already responded to your assertions many times. If you don't want to be crackpots, you would do well to stop mindlessly repeating them without any regard to the received criticism. :rolleyes:

Umm, sorry, I think this was my first message in this thread... I apologie if I have missed something (I don't follow these forums too often). :tongue:

In the quantum computer: where else?

In fact, when I learned quantum computation in one of my classes, we learned it from a solidly Copenhagenist viewpoint.

Yes, you can always say something like "all the different calculations are performed simultanously as a superposition of every possible calculation", but that isn't exactly a physical description of what is happening in a quantum computer... it is more or less a description of the mathematics.

OK, let's assume that the MWI is false (which it, ofcourse, might be). How would you explain the physical behaviour of a quantum computer?

kvantti

Sep13-06, 08:52 AM

Tell me then, how does the quantum computer in our Universe communicate with all the other 'virtual quantum computers' in the other Universes?

Through quantum interference. Different universes can interfere with each other if the quantum state of the system involved is coherent (as in a quantum computer).

Also, where is this quantum computer you speak of? This is such an abstract idea that the quantum computer calculates some of the sub-problems in other dimensions that I'm not sure it warrants a response. I'm ignorant on this subject, but what experiments have been done to confirm your quote?

IBM has the most advanced quantum computer nowadays with seven qubits. See this (http://domino.research.ibm.com/comm/pr.nsf/pages/news.20011219_quantum.html).

Oh and mathematically you can just say that "all the different calculations are in a superposition in the quantum computer during the calculation", if you don't want to think the MWI way.

Careful

Sep13-06, 09:38 AM

Huh? :confused: I mean to say that I think RQM > MWI > Copenhagen > Bohm.
But what is YOUR idea about quantum mechanics ?!! This entire discussion is about one's favorite color of spaghetti, while all the pasta tastes the same. It seems to be much more intelligent to place this question in the light of some problematic aspects of modern theoretical physics : (a) the problem of vacuum energy vis a vis the cosmological constant (b) the issue of realism (c) the problem of time (d) the validity of special relativity at all energy scales. Then, depending upon your answers on these (and other) issues you will find yourself confined to one of these religions, or you feel the logical need to dig deeper into QM itself. One question to start with for example is wheter one truely believes gravity to be necessary to even obtain a well defined theory of quantum electrodynamics.

Careful

NateTG

Sep13-06, 09:41 AM

OK, let's assume that the MWI is false (which it, ofcourse, might be). How would you explain the physical behaviour of a quantum computer?

That's not a useful stipulation. MWI, Bohmian Mechanics, and the Plug and Chug interpretation all make identical predictions so the only way that MWI can be scientifically falsified is if all of the other interpretations also have the same problems.

Moreover, and this is something people love to ignore, physics does not and will never explain anything rather, physics is a collection of theories that make predictions. Statements like 'things fall because of gravity' are misleading - it would be better to say 'we call the tendency of things to fall gravity'.

As such, interpretations of quantum mechanics are (from a scientific point of view) really primarily interesting because they can lead to experimentally verifiable predictions. Otherwise, we might as well be discussing how many angels can dance on the head of a pin.

The fact is that (assuming the physics is correct) the quantum computer will work regardless of whether you think of it as a bunch of intereacting 'worlds', a winding maze of particle paths, or a black box.

RandallB

Sep13-06, 10:40 AM

They said IF they actually make a true Quantum-Computer, it will, (IMO they won’t).
They already have. They just haven't made a "big" one.
What does that mean – something like a little bit pregnant but not really yet?

Plus even if they can come up with Q-C or other proof of MWI convincing to those that are not already convinced, that still only ‘proves’ one reality.

MWI is one thing but it doesn’t call for more than one reality!
The idea that one reality where say MWI is correct and BM is wrong;
and a second reality where say BM is right and there are no MW’s of MWI; ----- And Are both true ?????

IMO that is beyond an ‘ad hominem fallacy’ it just logically ridiculous.
What argument would not fall on its own merit trying to support such a thing with anything like rational logic?

AnssiH

Sep13-06, 11:19 AM

Well, here is a challenge for you (and for everyone who doesn't believe in the MWI) from Deutsch (as presented in his book The Fabric of Reality):

Explain where the calculations made by a quantum computer are performed when it solves the sub-problems associated with a single problem. Eg. when factoring a 250-number digit using the Shor's algorithm (http://en.wikipedia.org/wiki/Shor's_algorithm), the number of sub-problems is about 10^500 (the number of particles in the universe is about 10^80).
And yet, a quantum computer solves all the sub-problems at the same time. So how can it solve 10^500 problems during only one calculation, if we have only one computer in only one universe?

(It would take classical computer 10^500 times the time of a quantum computer to perform the same operation)

And for the question why the MWI has become "some sort of religion": it gives a coherent, local and deterministic description of reality and in my point of view, it would be illogical that there would be only one universe. Didn't you think that there are "other dimensions" when you were a kid? :rolleyes:

Like I've said in about every post to this thread, we make certain assumptions about "what exists" in reality and about how they behave to come to explain how the reality works to our selves. The above questions, about where the "calculations" happen and so on, only make sense in so far that you want to talk about "calculations" (and the related entities and concepts that you imagine is performing these "calculations", in this case in multiple universes) and MWI makes sense only in so far that you make certain assumptions about such things as the reality of a photon and interference between universes.

In fact, if you take a look at the opening post here:
http://www.physicsforums.com/showthread.php?t=130623
you'll notice how one can say the "calculations" happen or rather simply "exist" in static manner in spacetime just by insisting that spacetime really exists the way Einstein believed it to exist (Of course it will be difficult to explain why there seems to exist any "moments" at all, but that's a different discussion). One way to put it would be to say that the photon moves back and forth in time so that all its possible trajectories interfere, but this is wrong vocabulary because there is no motion in spacetime.

I am confident that all interpretations have their own answers about how the phenomena happen so to come to predict the exact same observable phenomena. So after all is said and done, many-worlds interpretation is just that, an "interpretation". At this stage we cannot pick and choose any QM interpretation to be the real deal.

Also if you have followed my posts in this thread you might have noticed how I've asserted that - quite likely - the reason why QM seems so damn odd to us is that we are trying to explain a behaviour of such entities that do not exist in such manner as we imagine them to exist. It is like explaining the behaviour of a rainbow after asserting it is an object which originates from a pot of gold, and only once one realizes how rainbow is rather the interference pattern on the surface of the observer, its behaviour starts to make sense.

Likewise, if you insist on the information between atoms to travel in the form of tiny billiard balls and on top of that imagine the motion of those billiard balls to exist in newtonian sense (only look at it from one inertial frame) you may be forced to assert that the photon exists in many worlds so to exhibit the behaviour we observe. We may have to question the nature of many things to come up with more accurate answers, like the nature of space, matter, light, motion(/time), energy... Maybe even discard these concepts to understand this system we call "reality" from a completely new angle.

(On a related note, have people formed opinions about this idea of discrepte, stepwise spacetime expansion causing quantum behaviour?
http://www.estfound.org/
Haven't had time to really look into it, does it show some obvious weaknesses right off the bat?)

So, just what NateTG is saying, physics really is quite literally a collection of theories or rather assumptions about what exists and how they behave. And like I said before, because of how our understanding works physically, we can only deal with reality by assuming there exists such and such entities and asserting they have such and such relationships between each others. Because this is the only thing we are capable of, it seems to us that reality really is like this, but little bit of philosophy can show that this is not exactly true; reality does not actually work with concepts. The mental model we have about reality in our head really is just an expression of the real thing, and it is not accurate or even "the metaphysically correct way" to express reality. (And any math you produce is also merely describing the behaviour of some "entity" you imagine to exist metaphysically in that sense)

And btw, MWI gaining ground as the "favourite way" to describe reality in some circles doesn't mean it is true, it just means it is one of the easiest ways to "imagine/visualize" QM phenomena in your mind. Think about how you try to visualize any black-box system when you are trying to back-engineer how its behaviour comes about, and you will realize how the assumptions with which you find it easiest to imagine the functions of the black box don't mean that is actually what happens inside. There are always many ways to produce some desired behaviour. Any system builder/programmer knows this very well.

And my comments about MWI becoming a religion are referring to how I find that MWI-people are continuously asserting theirs is "the only possible interpretation". Please understand that no one is saying it "cannot be true", but that it is not something that has been proven to be true in any sense. I am certainly happy to see many sensible people at this thread who still understand this, and I hope MWI won't become so standard that considering other options will be viewed as heretical or crackpot. It is important to be honest about it being just an interpretation unless you want to see everyone believe in it like a religion. And you don't want this to happen if you believe in scientific method, yes?

Chaos' lil bro Order

Sep14-06, 12:16 AM

Through quantum interference. Different universes can interfere with each other if the quantum state of the system involved is coherent (as in a quantum computer).
.

Are you talking about p-branes?

What defines two events in MWI anyways? I mean what is the smallest increment of information, whether it be spacial, temporal, or any other physical property you can think of, that must occur before the 'father' universe splits into two and the 'daughter' universe is birthed?

Hurkyl

Sep14-06, 12:45 AM

This entire discussion is about one's favorite color of spaghetti, while all the pasta tastes the same.
Right -- but I was talking to someone who thinks spaghetti has to be purple, and thinks that my motivation for saying all pasta tastes the same is because I'm an idiot that doesn't like purple.

AnssiH

Sep14-06, 12:54 AM

I believe the idea is rather, that all the possible universes exist "all the time" and interfere with each others. So the model is relying on certain ideas about how photons exist and how they interfere with other photons in other universes.

So, when someone is claiming this is the only way QM could work, I might just as well start asserting that when a rainbow seems to mimic the motion of the observer without delay, it can be explained in non-local terms only by assuming we are seeing a rainbow of a "different universe" every time we move.

Sure, this would make the phenomenon local, but in the case of rainbow we now know enough about how it exists to be able to see how its observed "motion" occurs in completely classical terms and within one universe, and yet there is a different rainbow visible for every observer, or rather that we should not assign identity to a rainbow; there is no rainbow at all without an observer. (This is a case of realism where something cannot exist without an observer, in completely classical sense)

Likewise with QM, the motion or the "apparent trajectory" of the photon really does depend on where it's going to be observed (one way or another), and to assume there really was a photon (with identity) in flight is already an assumption that is likely to be wrong to some extent, and will lead you to assert there must be multiple universes and we are merely observing photons from one.

So, what I'm saying is... dig deeper gentlemen.

Careful

Sep14-06, 01:37 AM

Right -- but I was talking to someone who thinks spaghetti has to be purple, and thinks that my motivation for saying all pasta tastes the same is because I'm an idiot that doesn't like purple.
Hehe, I noticed that, but you also said that you might choose for the relational colored one, once this color would gain more popularity. My point being that whatever interpretation you pick, you keep on being stuck with some embarrasing shortcomings of the formalism itself. For example, I have to think hard about Bell inequality violation and spin statistics in Barut self field (although I could put them in by hand), but there is absolutely no problem with realism, time, special relativity and vacuum energy (tell that to some QG people - all their deep problems vanish in thin air).

Cheers,

Careful

Hurkyl

Sep14-06, 02:05 AM

Hehe, I noticed that, but you also said that you might choose for the relational colored one, once this color would gain more popularity.
I prefer RQM over MWI now -- but if I was asked to choose between the popular interpretations I'd have to pick MWI since AFAIK, RQM isn't one of them yet.

you keep on being stuck with some embarrasing shortcomings of the formalism itself
Embarassing shortcomings are in the eye of the beholder.

Careful

Sep14-06, 02:25 AM

I prefer RQM over MWI now -- but if I was asked to choose between the popular interpretations I'd have to pick MWI since AFAIK, RQM isn't one of them yet. Embarassing shortcomings are in the eye of the beholder. This is exactly the miss-election attitude I was referring to in the beginning, I remember asking you what YOUR view towards QM is. Embarrasing shortcomings are not in the eyes of who percieves them, but in those minds which do not wish to adress them even when it is well known that the latter issues are definetely problematic. String theory does adress the vacuum problem by making a supersymmetric ansatz : at that moment, you can say whether you find such mechanism using exotic particles credible or not (I certainly don't). Anyway, if you do not believe some detailed matter content to be responsible for the cancellation of the vacuum energy, then the most direct step would be to question the phenomenon (in either the renormalization procedures) at its very roots.

Careful

kvantti

Sep14-06, 09:45 AM

I was writing a long post and my computer crashed so I'm pretty frustrated at the moment and therefore I will state my matter briefly:

NateTG:

That is an instrumentalist point of view. I'm glad that not all physicists are instrumentalists.

AnssiH:

You obviously believe in some sort of "hidden variable" theory. Fair enough. But keep in mind that even you are interpreting quantum mechanics from your own point of view, and in my eyes it doesn't differ from the Copenhagen interpretation; you and CoI state that the formulas of quantum mechanics do not describe reality as it is, but only probabilities of observations within reality. The difference between CoI and your interpretation is that the CoI doesn't explain how the "probablities" can interfere and entangle... it just says they do. You seem to have your own vision how they actually do interfere (as we all do).

The MWI says just the opposite: the formulas of quantum mechanics describe reality as it is. What would be simpler? The concept of multiverse emerges naturally from this kind of thinking. It also explains quantum interference and entanglement in a very simple manner.

It is important to be honest about it being just an interpretation unless you want to see everyone believe in it like a religion. And you don't want this to happen if you believe in scientific method, yes?

Yes, it is "just an interpretion" of quantum mechanics. But it also a "theory" of multiverse. A theory that most quantum cosmologists and quantum computer researchers find compelling, because it offers explenations of the physical behaviour of the quantum system they study, rather than just "cold mathematics".

-- you'll notice how one can say the "calculations" happen or rather simply "exist" in static manner in spacetime just by insisting that spacetime really exists the way Einstein believed it to exist.

This isn't true in the case of quantum computers; the calculations are based upon quantum effects, such as quantum interference and entanglement, so you can't just say "it just acts as if the different calculations would interfere, but actually they don't; the calculation and the result just already exist in a static spacetime." Quantum computers actually prove that quantum interference and entanglement are real phenomenom; not just illusions of "static spacetime." And that been said, you can't say that a photon moves as if it would interfere with itself; it actually does interfere with itself.

tehno

Sep14-06, 10:24 AM

Sorry for interrupting this discussion,I'm really no expert on this but I can't resist not to ask.
With their capability of processing information can a quantum computer one day answer the ethernal question of finite strategy games:say Chess or GO?Estimation is that there are about ~10^{60} legal chess positions.

kvantti

Sep14-06, 11:18 AM

Are you talking about p-branes?

What defines two events in MWI anyways? I mean what is the smallest increment of information, whether it be spacial, temporal, or any other physical property you can think of, that must occur before the 'father' universe splits into two and the 'daughter' universe is birthed?

Here (http://www.hedweb.com/manworld.htm) is a FAQ considering the MWI. You'll probably find answers for your future questions there. A single universe is irreversibly split into many universes when the quantum system involved in the splitting decoheres. But that doesn't mean the decoherence causes the splitting; the universes split all the time, be there interactions or not. Decoherence only distinguishes the universes from each other and therefore they can't interfere with each other anymore.

Sorry for interrupting this discussion,I'm really no expert on this but I can't resist not to ask.
With their capability of processing information can a quantum computer one day answer the ethernal question of finite strategy games:say Chess or GO?Estimation is that there are about ~10^{60} legal chess positions.

Yes, a quantum computer can resolve this kind of calculation very fast.

NateTG

Sep14-06, 01:04 PM

Yes, a quantum computer can resolve this kind of calculation very fast.

Quantum computers are not proven to solve NP hard problems in polynomial time, and, in fact, are strongly expected no to.

AnssiH

Sep14-06, 02:11 PM

You obviously believe in some sort of "hidden variable" theory. Fair enough.

No, I don't particularly believe in hidden variables or copenhagen. I believe our ideas about what exist are currently wrong at a deeper level than where any of the mainstream interpretations reach. (Like what is "motion" and so on) I believe one day someone will figure out a really simple deterministic explanation and everybody will slap on their forehead and go "doh!"

Well okay maybe there's some arguments back and forth first :)

This isn't true in the case of quantum computers; the calculations are based upon quantum effects, such as quantum interference and entanglement, so you can't just say "it just acts as if the different calculations would interfere, but actually they don't; the calculation and the result just already exist in a static spacetime." Quantum computers actually prove that quantum interference and entanglement are real phenomenom; not just illusions of "static spacetime."

Obviously to interpret this in terms of static spacetime you also have to assume that what we see as a photon is in fact just a wave-like connection between two atoms over spacetime (i.e. something with "volume", which occupies all the possible "trajectories". and in such manner that the shape of the "beginning" of the travel is affected by the shape of the "end").
If you keep thinking about photons as little balls it won't help you at all to look at it from the point of view of its own inertial frame (where "delayed choice" experiments are not "delayed choice" at all), unless of course you imagine the situation as if this little ball bounces back and forth in time over every possible trajectory. But to think about it this way you are confusing a whole new concept of "time progression" within spacetime itself, so...

Of course no one can say which idea of photons is more correct metaphysically, but this is just what I'm saying about how our ideas about what exists and in what manner are just assumptions, and they are bound to remain as assumptions forever, although I believe we can still peel much deeper than where we currently are.

And that been said, you can't say that a photon moves as if it would interfere with itself; it actually does interfere with itself.

Of course it does, although again, if you talk about the phenomenon in different terms, it may become meaningless to say it metaphysically interferes with itself, because it is meaningless to assign any identity to the photon in the first place. If you consider the so-called "photon" to literally be the "beep" that the atom does (i.e. when we say "the atom received a photon"), and the beep to be caused by a wave-like energy finding its way over all the possible routes to that atom (note that this is different from a wave propagating to all directions), you could only say there is wave-like energy that interfered with itself and no photon with identity ever made any journey.

But the trick is of course that you'd have to consider this to happen not over space but over spacetime. And let it be said that my confidence in the existence of spacetime is not particularly high either, I think spacetime too is a concept that is very much incorrect from what really exists.

So, if I have to make a bet about an interpretation, just for fun, I bet they are all going to be considered ridiculous when some assumption about something very fundamental will fall in place and show us more accurate view of all the phenomena we observe. Something akin to the shift from relative motion to relative time in relativity. (here I go again, praising relativity... silly me :P )

You may be tempted to say "maybe MWI is just this idea", but to me MWI is like all the other interpretations, and they are basically arguing about whether everything is made out of "earth, air, water and fire" or from "solid, liquid and gas", or perhaps the fundamentals are "opaque" and "transparent" matterpieces, when they should be concentrating on much much deeper issues. Something like, how could inertia be fundamental? Think about that.

Chaos' lil bro Order

Sep14-06, 08:34 PM

Here (http://www.hedweb.com/manworld.htm) is a FAQ considering the MWI. You'll probably find answers for your future questions there. A single universe is irreversibly split into many universes when the quantum system involved in the splitting decoheres. But that doesn't mean the decoherence causes the splitting; the universes split all the time, be there interactions or not. Decoherence only distinguishes the universes from each other and therefore they can't interfere with each other anymore.

Yes, a quantum computer can resolve this kind of calculation very fast.

'A single universe is irreversibly split into many universes when the quantum system involved in the splitting decoheres.'

Fair enough. Now tell me the variables of the 'quantum system' and what constitutes 'decoherence'. I'm tired of all these big words being thrown around without any real meaning behind them. This is not true understanding IMO, its akin to cut and pasting a wikipedia entry or repeating popular phrases found in books like 'The elegant Universe'. Can this thread get down the to nitty-gritty already, its becoming muddied with pop-science and its really pissing me off now.

Chaos' lil bro Order

Sep14-06, 08:52 PM

Upon reading some of the text from your link I found this explanation on why universes split according to MWI:

'The precise moment/location of the split is not sharply defined due to the subjective nature of irreversibility, but can be considered complete when much more than kT of energy has been released in an uncontrolled fashion into the environment. At this stage the event has become irreversible.'

It appears that MWI defines the splitting of a universe as when an 'irreversible' event takes place in it. The example given was the irreversibility of thermodynamic processes. But the statement above says that the splitting event isn't even clearly defined due to the subjective nature of irreversibility. My word, this MWI theory is turning out to be a big joke the more I read about it. I mean heck, it can't even make sharp concrete predictions even within its own framework, so why should anyone take it seriously. It seems like just another theory that defers what we do not understand about our universe to some sort of mystical idea that's no more falsifiable than god. It hinges on a subjective process, lmao!

AnssiH

Sep15-06, 02:06 AM

Perhaps I'll throw in couple of questions myself. I don't ask these in the intent to show MWI false, but to find out some details of the model.

From FAQ:
For two branches or worlds to interfere with each other all the atoms, subatomic particles, photons and other degrees of freedom in each world have to be in the same state, which usually means they all must be in the same place or significantly overlap in both worlds, simultaneously.

"All the other atoms etc..." refers to what? All the atoms in the universes? Or just all the atoms of some smaller system? I.e. is it enough if in two worlds there just happens to exist an identical geiger-counter in the same "place" for them to interfere, even if the rest of the atoms in these worlds are different?

How do we identify "place", or rather, what justifies us to even assume that space is like an invisible backdrop where each location has identity?

What do we mean with the parts being "simultaneously" at the same place. Does this mean they not only have to exist in the same "place" but also in the same inertial frame? (Since in relativity any object with volume will not occupy the same "place" simultaneously from two different inertial frames)

Worlds irrevocably "split" at the sites of measurement-like interactions associated with thermodynamically irreversible processes

What does "at the sites of measurements-like interactions" mean here. Is it just the "site" that splits or the whole universe? I.e. Only the parts in the geiger-counter it that moved irreversibly, or everything?

If it is latter, when do they split? If you are observing the geiger-counter from 10 lightseconds away, will you split 10 light-seconds after counter or simultaneously?

If latter, simultanously in which inertial frame and why?

If it's in your own simultaneity, what if you are approaching the geiger-counter at great speeds when the split occurs at the counter, and then brake into the same frame as the counter so that the split hasn't happened yet in this frame. Will the split reverse too?

Contact between a system and a heat sink is equivalent to increasing the dimensionality of the state space, because the description of the system has to be extended to include all parts of the environment in causal contact with it.

Are not all things causally connected to everything in the universe? Does MWI assume that "causal connection" is something that exists metaphysically, instead of just a loose semantical concept? If so, how does it exists?

And also, does MWI comment on what causes the photon to take one or another route in the beam splitter within one universe, or is it still just "non-caused", arbitrary thing?

(btw, I don't much appreciate how the FAQ states "There is no other quantum theory, besides many-worlds, that is scientific". This is just the kind of definition bending that you'd expect from religious people.

kvantti

Sep15-06, 03:54 AM

AnssiH:

OK. Let's forget about photons. Electron is a particle that has an inertial frame and it can interfere with itself in the double slit. And yet, the electron is completely localized particle according to the Heisenberg picture. So classically thinking, for it to interfere with itself, it would have to go thru both slits at the same time and travel to all the possible directions after that. Then for some magical reason, the electron is observed only in one place.

I'll reply to your questions in another post, if no one else has before that.

Now tell me the variables of the 'quantum system' and what constitutes 'decoherence'.

Varying observables: spin, momentum, position, energy, time. These are all that I can recall.

Decoherence: the loss or absence of interference within a quantum system due to interaction (and therefore entanglement) with another quantum system. I can't explain it simpler. You should just study the concepts.

'The precise moment/location of the split is not sharply defined due to the subjective nature of irreversibility, but can be considered complete when much more than kT of energy has been released in an uncontrolled fashion into the environment. At this stage the event has become irreversible.'

You misinterpreted this. The splitting isn't sharply defined in one universe, because a single universe splits all the time in the multiverse, and you can't tell in which universe you are until the splitting has become irreversible due to decoherence within the quantum system that has been split. In other words, before you observe the state of the quantum system, you can be in every possible universe where the quantum state hasn't decohered yet. That is what the author means when he writes "the split is not sharply defined due to the subjective nature of irreversibility."

Don't jump into conclusions. :wink:

AnssiH

Sep15-06, 05:04 AM

AnssiH:

OK. Let's forget about photons. Electron is a particle that has an inertial frame and it can interfere with itself in the double slit. And yet, the electron is completely localized particle according to the Heisenberg picture. So classically thinking, for it to interfere with itself, it would have to go thru both slits at the same time and travel to all the possible directions after that. Then for some magical reason, the electron is observed only in one place.

Well I wouldn't consider any sub-atomic element in the atomic model to be a point-like particle at all, because our idea of a point-like things are based on stable pieces of matter. The stable elements that bring about this spatial stability as their emergent feature are probably not stable in the same manner at all. I don't have any answer as to the better description of what "electron" is, but let it be said that this question is indoubtedly going to be an important one (and incidentally it is one question that, AFAIK, troubled Einstein's mind greatly at his later years)

As an interesting philosophical excercise, consider Milo Wolff's spherical standing waves. Disregarding if his idea can be real or not, it is interesting to note how radically different fundamentals could bring about so similar measurable effects.

Also with experiments with electrons it becomes important to consider the reality of electromagnetic fields that are used to move the particles (and like I said, possibly the fundamental reality of motion)

More interesting but related problem, as I mentioned in the other thread myself, is that they have been able to make full atoms produce interference pattern. (I've been trying to find more details about these experiments)

Yet it doesn't seem to me at all that MWI "must be true", but instead my head is spinning with all the options that are still open and greatly unexplored (and cannot be explored without a decent army of scientists really spending time at taking the parts of this problem down and looking at it in completely new ways, like Einstein looked at the motion of light).

I'll reply to your questions in another post, if no one else has before that.

No hurry, I'll be away for about a week... Take care now!

kvantti

Sep15-06, 05:07 AM

For two branches or worlds to interfere with each other all the atoms, subatomic particles, photons and other degrees of freedom in each world have to be in the same state, which usually means they all must be in the same place or significantly overlap in both worlds, simultaneously.

"All the other atoms etc..." refers to what? All the atoms in the universes? Or just all the atoms of some smaller system? I.e. is it enough if in two worlds there just happens to exist an identical geiger-counter in the same "place" for them to interfere, even if the rest of the atoms in these worlds are different?

The universes need to be almost identical for them to interfere. For example, when performing a double-slit experiment with single electrons, you get two significant sets of universes: in 50% of the universes the electron went thru the left slit and in another 50% it went thru the right slit. Since identical, these two sets of universes can interfere, giving the observed interference pattern after many electrons have been "shot" thru the slits.

If we observe which slit the electron goes thru, the universes decohere from each other and are not identical anymore. You get two sets of universes: in 50% of the universes the electron is observed to go thru the left slit and in another 50% of the universes thru the right slit. The universe is irreversibly split into two sets of universes that can't interfere with each other. So in this case we don't observe the interference pattern forming.

Does this mean they not only have to exist in the same "place" but also in the same inertial frame?

Yes, you just "look" the situation from the inertial frame of the quantum system in question. In the MWI, different inertial frames are just special cases of different universes. In other words, every inertial frame can be thought to be it's own universe (or rather, a different view of the same universe; likewise different universes are just different views of the multiverse). It is rather complicated, because the multiverse is a multidimensional "object". No one knows how many dimensions. String theory suggests 10 dimensions.

What does "at the sites of measurements-like interactions" mean here. Is it just the "site" that splits or the whole universe? I.e. Only the parts in the geiger-counter it that moved irreversibly, or everything?

Measurement-like interaction is any interaction that entangles the observed quantum system with the observers quantum state upon interaction. The whole universe is split, but the resulting universes don't have to differ radically; a single quantum event happening differently in two universes is enough for splitting. A double-slit experiment is a good example of this.

If it's in your own simultaneity, what if you are approaching the geiger-counter at great speeds when the split occurs at the counter, and then brake into the same frame as the counter so that the split hasn't happened yet in this frame. Will the split reverse too?

That is a question you need to ask from a quantum cosmologist; I have no clue... and I don't want to speculate. :rolleyes:

Are not all things causally connected to everything in the universe? Does MWI assume that "causal connection" is something that exists metaphysically, instead of just a loose semantical concept? If so, how does it exists?

Every event that is causally connected with a certain quantum system is entangled with the quantum system. That is all there is to it.

And also, does MWI comment on what causes the photon to take one or another route in the beam splitter within one universe, or is it still just "non-caused", arbitrary thing?

The MWI is quite clear about it: in 50% of the universes the photon goes thru the beamsplitter and in another 50% it gets reflected from it. You end up in both universes, but because subjectivily you experience only one universe, it seems totally arbitrary. So you have 50% chance to experience one of the two sets of universes.

(btw, I don't much appreciate how the FAQ states "There is no other quantum theory, besides many-worlds, that is scientific". This is just the kind of definition bending that you'd expect from religious people.

This is true, but it is still the best FAQ about the MWI. :blushing:

RandallB

Sep15-06, 10:54 AM

Quantum computers . not proven to solve NP hard problems ... .Couldn't find it used in other posts - What does "NP" stand for??

NateTG

Sep15-06, 12:52 PM

Couldn't find it used in other posts - What does "NP" stand for??

NP is the set of problems whose answers can be checked in polynomial time.

Chaos' lil bro Order

Sep16-06, 12:24 AM

Fine then, I think we disagree and nothing can be said by either to sway one's opinion on MWI.

One last question. What is the smallest event that can split a universe in two?

kvantti

Sep16-06, 05:02 AM

Well I wouldn't consider any sub-atomic element in the atomic model to be a point-like particle at all, because our idea of a point-like things are based on stable pieces of matter. The stable elements that bring about this spatial stability as their emergent feature are probably not stable in the same manner at all. I don't have any answer as to the better description of what "electron" is, but let it be said that this question is indoubtedly going to be an important one (and incidentally it is one question that, AFAIK, troubled Einstein's mind greatly at his later years)

Particles are point-like in the way that they don't have any spatial size. In our most fundamental theory of reality (the quantum field theory) particles are quantas of energy of different quantum fields. How could energy have any "size"? The classical "size" of any particle is defined by its Compton wavelenght (http://en.wikipedia.org/wiki/Compton_wavelenght).

As an interesting philosophical excercise, consider Milo Wolff's spherical standing waves. Disregarding if his idea can be real or not, it is interesting to note how radically different fundamentals could bring about so similar measurable effects.

Same for the string theory. It is consistent with every observation because it doesn't make any new predictions at the energy scale we can handle nowadays with our most powerful particle accelerators. It isn't falsifiable.

Also with experiments with electrons it becomes important to consider the reality of electromagnetic fields that are used to move the particles (and like I said, possibly the fundamental reality of motion)

I see no problem seeing motion as an illusion... then again, I think the whole universe we perceive is an illusion of some sort. :biggrin:

More interesting but related problem, as I mentioned in the other thread myself, is that they have been able to make full atoms produce interference pattern. (I've been trying to find more details about these experiments)

Not just full atoms, but whole molecules too! In the '99 a research team was able to observe the self-interference of a buckyball (http://wwwcsif.cs.ucdavis.edu/~cs175/Images/Buckyball.png), a carbon-60 molecule. Here (http://physicsweb.org/articles/news/3/10/12/1) is an article about the experiment.

So we have little balls of matter interfering with themselves. Nice.

Yet it doesn't seem to me at all that MWI "must be true", but instead my head is spinning with all the options that are still open and greatly unexplored (and cannot be explored without a decent army of scientists really spending time at taking the parts of this problem down and looking at it in completely new ways, like Einstein looked at the motion of light).

Yes, the MWI doesn't have to be true, but it is the simplest way to explain the physical behaviour of quantum phenomenom, like the self-interference of buckyballs. Thus, it is favoured by the Occam's razor and this is the main reason I prefer it over other interpretations.

tehno

Sep16-06, 01:05 PM

Quantum computers are not proven to solve NP hard problems in polynomial time, and, in fact, are strongly expected no to.
I admit I'm dissapointed to hear that "secret" of a chess game will remain
undiscovered for a long time then.:cry:
I really thought that quantuum computer would resolve final status of the game in the near future...

charlylebeaugosse

Sep16-06, 08:56 PM

Travis Norsen has written an article entitled "Against Realism". In it, he argues that the phrase "local realism" is not meaningful.

Against Realism (2006) (http://www.arxiv.org/abs/quant-ph/0607057)

Abstract:
"We examine the prevalent use of the phrase “local realism” in the context of Bell’s Theorem and associated experiments, with a focus on the question: what exactly is the “realism” in “local realism” supposed to mean? Carefully surveying several possible meanings, we argue that all of them are flawed in one way or another as attempts to point out a second premise (in addition to locality) on which the Bell inequalities rest, and (hence) which might be rejected in the face of empirical data violating the inequalities. We thus suggest that this vague and abused phrase “local realism” should be banned from future discussions of these issues, and urge physicists to revisit the foundational questions behind Bell’s Theorem."

-----

My questions for your consideration:

1. What does realism mean to you?

2. Einstein said: "I think that a particle must have a separate reality independent of the measurements. That is: an electron has spin, location and so forth even when it is not being measured. I like to think that the moon is there even if I am not looking at it." Is this realism?

3. In your opinion, is "realism" an assumption of Bell's Theorem? If so, where does it arise?

==========
For such matters, see
Einstein, Tolman, and Podolsky, Physical Review 37, (1931) 780-781
to wash out many errors that tend to make Einstein much more naive than he really was.

setAI

Sep16-06, 10:14 PM

Quantum computers are not proven to solve NP hard problems in polynomial time, and, in fact, are strongly expected no to.

ehem: :rolleyes:

using quantum computation to solve NP complete problems:

http://www.arxiv.org/abs/quant-ph/9912100
http://www.arxiv.org/abs/quant-ph/9801041
http://www.arxiv.org/abs/quant-ph/0508177

RandallB

Sep17-06, 02:32 PM

Found it! --- NP stands for Nondeterministic Polynomial Time ...
NP-completeness difficult stuff.
But for this line of reasoning to confirm that QM and the MW interpretation of it (That MWI is an interpretation of QM may just be my opinion) is correct don’t we have to assume that the Classical view must be deterministic.
Has it been shown that Classical cannot be Nondeterministic, or is that something that is just assumed?

AnssiH

Sep25-06, 07:58 AM

Yes, you just "look" the situation from the inertial frame of the quantum system in question. In the MWI, different inertial frames are just special cases of different universes. In other words, every inertial frame can be thought to be it's own universe (or rather, a different view of the same universe; likewise different universes are just different views of the multiverse). It is rather complicated, because the multiverse is a multidimensional "object". No one knows how many dimensions. String theory suggests 10 dimensions.

A bit off-topic but I have to make sure, don't the extra dimensions in string theory just refer to the fact that the strings would have to move/vibrate in more than 3 dimensions? (Which to me sounds like the dimensions could be just as well thought of as some completely different property than spatial dimensions, like an ordinary string could vibrate spatially and by "colour", etc...)

Particles are point-like in the way that they don't have any spatial size. In our most fundamental theory of reality (the quantum field theory) particles are quantas of energy of different quantum fields. How could energy have any "size"? The classical "size" of any particle is defined by its Compton wavelenght (http://en.wikipedia.org/wiki/Compton_wavelenght).

Yeah, definitely concepts like "size" need to be viewed critically here, but not only that, also we must view critically any sort of concept of particles. And the whole concept of "identity". Not only when we imagine identity to such thing as "photon", but even if we think about the universe as if it's one big continuous "fluid" where particles exists as stable standing waves (or whatever), we have still tacked identity to this "fluid". It may seem very obvious that something must have an identity in objective reality, but it must be noted that this intuitive view has bitten ourselves in the *** so many times on so many issues, that I'm becoming convinced that "identity" is a non-sensical concept as far as metaphysics is concerned. For example, it is completely arbitrary and without any empirical evidence, to assume that locations of space or spacetime have any identity to them. It is odd that physicists ever expected it to be so.

And having said that, even though we "kind of" understand the above, we still naturally imagine QM-situations in terms of things that have identity to themselves (instead of being stable patterns onto which one can arbitrarily tack identity, like onto a "standing wave" or a "shadow"). The fact that we consistently find such behaviour as we could expect a quantum mechanical electron to cause, does not mean there must "really" be a metaphysical electron. It just means there is some process causing this behaviour. Just like the fact that we consistently find our shadow to follow us, doesn't mean there actually is such an object with identity as a "shadow".

As a more concrete point in case, we can talk about how a photon, if energetic enough, can turn into an electron, or more vaguely, how energy can turn into matter (or vice versa), but is it not much more proper to understand that all these "fundamental particles" are not in fact fundamental at all. It is not like the energy as one fundamental thing just magically turns into some other fundamental thing (that has "fundamental inertia"). It's more proper to understand these particles as emergent features of whatever causes them, and their behaviour is also, after all is said and done, governed by their underlying causes (and I think one important question is going to be "what is charge metaphysically?").

I see no problem seeing motion as an illusion... then again, I think the whole universe we perceive is an illusion of some sort. :biggrin:

Well, the problem with calling something an "illusion" is that it means one basically just refuses to give any cause to some phenomenon. Sure we should expect motion to be something different from what it readily seems, but even more so we should expect "time" to be something different than what it seems, because it is a concept that is derived from "motion". I get a rash from the interpretation that the flow of time is just "an illusion in a static spacetime", because that is the same as saying "reality is static and conscious experience is magic". I understand the need for the word in some cases but it really is very very dangerous word that ought to be avoided :)

That being said, what is very important to understand is that as long as one talks about the concept of spacetime, he must also remember that nothing moves in spacetime. We are so used to the idea of "motion" that otherwise astute people often confuse the concepts of "spacetime" and "motion" together in incoherent ways. For example when they talk about how a photon "moves back and forth" in spacetime.

It must be understood that if spacetime is what is used to describe motion, you cannot then assert that something is in fact moving inside spacetime, for you would need a new time dimension to describe that motion. The matter of the fact is that metaphysical spacetime and metaphysical motion are mutually exclusive concepts. We can only have one or another. And to assert that only our "consciousness" moves in spacetime is also an assertion about motion "within" spacetime, regardless of if you call it an "illusion" or not.

This is not just a minor mathematical problem that can be dismissed, but it in fact highlights very concretely the problems of such assumptions as the metaphysical existence of spacetime (strictly speaking, the observable predictions of relativity don't require spacetime to exist because relativity of simultaneity cannot be directly observed). I don't think anyone has been able to actually make any explanation about how the "illusion of flow of time" could be achieved if nothing is in motion in reality, but everybody are very willing to dismiss the whole problem as meaningless because you really don't bump into it until you get to the philosophy of the mind, which may seem unrelated to physics, but it is not.

(Let it be said that I understand our subjective experience is very different from its immediate "causes" in objective reality, which is why I say it is an emergent feature of its parts)

Not just full atoms, but whole molecules too! In the '99 a research team was able to observe the self-interference of a buckyball (http://wwwcsif.cs.ucdavis.edu/~cs175/Images/Buckyball.png), a carbon-60 molecule. Here (http://physicsweb.org/articles/news/3/10/12/1) is an article about the experiment.

So we have little balls of matter interfering with themselves. Nice.

This is very interesting. Thanks.

-Anssi

AnssiH

Sep26-06, 02:38 AM

Not just full atoms, but whole molecules too! In the '99 a research team was able to observe the self-interference of a buckyball (http://wwwcsif.cs.ucdavis.edu/~cs175/Images/Buckyball.png), a carbon-60 molecule. Here (http://physicsweb.org/articles/news/3/10/12/1) is an article about the experiment.

Does anyone have more information about this?

-Anssi

selfAdjoint

Sep26-06, 10:11 AM

Try here (http://www.physics.usu.edu/peak/phys_2710_fall06/Complementarity.pdf#search=%22double%20slit%20buck yball%22). A good general description of various double slit experiments including the buckyball one, and does elementary calculations using DeBroglie wave length.

kvantti

Sep27-06, 05:50 AM

A bit off-topic but I have to make sure, don't the extra dimensions in string theory just refer to the fact that the strings would have to move/vibrate in more than 3 dimensions? (Which to me sounds like the dimensions could be just as well thought of as some completely different property than spatial dimensions, like an ordinary string could vibrate spatially and by "colour", etc...)

Yes, the extra dimensions first came up because they were needed to represent the one-dimensional strings. But the six extra dimensions can also thought to be the "landscape" in which the different universes of the multiverse exist:

String theory proposes that the many different types of subatomic particles are really just different vibrations of tiny strings that are like minuscule rubber bands. The catch is that it only works if the strings have several extra dimensions in which to vibrate beyond the dimensions we see.

Why don’t we see the extra dimensions? A proposal dating to 1998 claims we’re trapped in a three-dimensional zone within a space of higher dimensions. Other three-dimensional zones, called “branes,” could also exist, less than an atoms’ width away yet untouchable. The branes are sometimes called different universes, though some theorists say they should be considered part of our own because they can weakly interact with our brane in some ways.
http://www.world-science.net/exclusives/060330_multiversefrm.htm

Yeah, definitely concepts like "size" need to be viewed critically here, but not only that, also we must view critically any sort of concept of particles. And the whole concept of "identity". Not only when we imagine identity to such thing as "photon", but even if we think about the universe as if it's one big continuous "fluid" where particles exists as stable standing waves (or whatever), we have still tacked identity to this "fluid". It may seem very obvious that something must have an identity in objective reality, but it must be noted that this intuitive view has bitten ourselves in the *** so many times on so many issues, that I'm becoming convinced that "identity" is a non-sensical concept as far as metaphysics is concerned. For example, it is completely arbitrary and without any empirical evidence, to assume that locations of space or spacetime have any identity to them. It is odd that physicists ever expected it to be so.

Yeah its funny, we can only observe the properties particles exhibit (mass, spin, charge etc.) and make models of the interactions and relations of those properties. So we don't acutally observe the particles, just their behaviour.
As I quoted Lee Smolin on the other forum, "a point in spacetime is not defined by its location -- its defined only by what physically happens at it." This is just fancy way of saying that we can't assing any specific "location" to spacetime itself; only to events in spacetime.

And having said that, even though we "kind of" understand the above, we still naturally imagine QM-situations in terms of things that have identity to themselves (instead of being stable patterns onto which one can arbitrarily tack identity, like onto a "standing wave" or a "shadow"). The fact that we consistently find such behaviour as we could expect a quantum mechanical electron to cause, does not mean there must "really" be a metaphysical electron. It just means there is some process causing this behaviour. Just like the fact that we consistently find our shadow to follow us, doesn't mean there actually is such an object with identity as a "shadow".

Are you referring to some hidden variable theory?

As a more concrete point in case, we can talk about how a photon, if energetic enough, can turn into an electron, or more vaguely, how energy can turn into matter (or vice versa), but is it not much more proper to understand that all these "fundamental particles" are not in fact fundamental at all. It is not like the energy as one fundamental thing just magically turns into some other fundamental thing (that has "fundamental inertia"). It's more proper to understand these particles as emergent features of whatever causes them, and their behaviour is also, after all is said and done, governed by their underlying causes (and I think one important question is going to be "what is charge metaphysically?").

Particles are quantas of energy according to quantum field theory. Why this explenation isn't satisfactory to you? When a particle decays to other particles, its just different field interactions changing the energy (of the quantum field) into another form. In the case of a photon, the electromagnetic interaction "splits" the quanta of the neutral spin 1 field into two quantas of the charged spin ½ field if the conditions are appropriate for this kind of interaction to happen. According to QED atleast. Charge is the probability for the charged spin ½ field (or the electron field) to interact with the neutral spin 1 field (the em-field).

Well, the problem with calling something an "illusion" is that it means one basically just refuses to give any cause to some phenomenon. Sure we should expect motion to be something different from what it readily seems, but even more so we should expect "time" to be something different than what it seems, because it is a concept that is derived from "motion". I get a rash from the interpretation that the flow of time is just "an illusion in a static spacetime", because that is the same as saying "reality is static and conscious experience is magic". I understand the need for the word in some cases but it really is very very dangerous word that ought to be avoided :)

Conscious experience isn't magic; the quantum state of a persons consciousness just differs at every area of spacetime, giving illusion of the "flow of time". The entropy of the brain increases when "moving forward" in time, or in other words: the quantum state of the consciousness is more disordered in the "future" areas of spacetime. And consciousnes doesn't "move" within spacetime (as you suggested before), but instead consciousness exists at every area of spacetime where the persons brain exist; just that in different areas of spacetime, the quantum states of the consciousness differ from each other.

That being said, what is very important to understand is that as long as one talks about the concept of spacetime, he must also remember that nothing moves in spacetime. We are so used to the idea of "motion" that otherwise astute people often confuse the concepts of "spacetime" and "motion" together in incoherent ways. For example when they talk about how a photon "moves back and forth" in spacetime.

Yes. Nothing moves in spacetime. Motion can be viewed completely as an illusion: when you observe some object moving, you really just remember the "past" position of the object differing from the "present" position of the object. When this happens continuously, you see the object "moving".

It must be understood that if spacetime is what is used to describe motion, you cannot then assert that something is in fact moving inside spacetime, for you would need a new time dimension to describe that motion. The matter of the fact is that metaphysical spacetime and metaphysical motion are mutually exclusive concepts. We can only have one or another. And to assert that only our "consciousness" moves in spacetime is also an assertion about motion "within" spacetime, regardless of if you call it an "illusion" or not.

Yup, nothing moves inside a static spacetime continuum, not even consciousness.

I don't think anyone has been able to actually make any explanation about how the "illusion of flow of time" could be achieved if nothing is in motion in reality, but everybody are very willing to dismiss the whole problem as meaningless because you really don't bump into it until you get to the philosophy of the mind, which may seem unrelated to physics, but it is not.

It has been explained. I just never realized your point until now... and now I feel stupid. :biggrin:

AnssiH

Sep28-06, 05:09 AM

Yeah its funny, we can only observe the properties particles exhibit (mass, spin, charge etc.) and make models of the interactions and relations of those properties. So we don't acutally observe the particles, just their behaviour.
As I quoted Lee Smolin on the other forum, "a point in spacetime is not defined by its location -- its defined only by what physically happens at it." This is just fancy way of saying that we can't assing any specific "location" to spacetime itself; only to events in spacetime.

Yeah, exactly

The fact that we consistently find such behaviour as we could expect a quantum mechanical electron to cause, does not mean there must "really" be a metaphysical electron. It just means there is some process causing this behaviour. Just like the fact that we consistently find our shadow to follow us, doesn't mean there actually is such an object with identity as a "shadow".

Are you referring to some hidden variable theory?

Nah, I'm not very fond of hidden variable theories, at least not when they still assume particles are at all times entities with spatial stability (i.e. "like tiny balls").

I'm just saying that we shouldn't look at any observed stable pattern as more than just that; a stable pattern. Any stable pattern, like a shadow of a building or a standing wave inside a room, could be understood as a stationary entity because there is a sense of stability to their existence, but physically we can't say they are entities that are just "sitting there", but instead there are stable patterns whose stability is a result of an active process.

And such appears to be the case for matter as well. Matter is not something that is just "sitting there". There is an active process that keeps what we call an atom (or a buckyball molecule) spatially stable.

It is possible that the relative motion between such spatially stable patterns is mechanically explainable by some model that also explains just why is there such spatial stability, and such models are likely to make very different assumptions about what exists fundamentally (as compared to the standard model), and may give QM phenomena a completely deterministic footing. E.g. the locations where we observe electrons (or phenomena associated to electrons) are not necessarily required to be such places where an entity called "electron" would have had to move in any newtonian sense at all, and this assertion is, I believe, completely valid option for a realist.

So you could say my belief is that we just haven't figured out the proper model yet, but that we are capable of doing so by letting go certain particularly sticky assumptions about reality.

Conscious experience isn't magic; the quantum state of a persons consciousness just differs at every area of spacetime, giving illusion of the "flow of time". The entropy of the brain increases when "moving forward" in time, or in other words: the quantum state of the consciousness is more disordered in the "future" areas of spacetime. And consciousnes doesn't "move" within spacetime (as you suggested before), but instead consciousness exists at every area of spacetime where the persons brain exist; just that in different areas of spacetime, the quantum states of the consciousness differ from each other.

Yes. Nothing moves in spacetime. Motion can be viewed completely as an illusion: when you observe some object moving, you really just remember the "past" position of the object differing from the "present" position of the object. When this happens continuously, you see the object "moving".

When you say "when this happens continuously", are you not invoking an idea of motion? (For there is no sense of something happening continously without pointing out continuous "moments" from spacetime)

Obviously it is very understandable idea that the "state of the brain is different at every area of spacetime" and it is only expressing the past at any particular "moment" we choose to point at in the spacetime, but even then, we cannot really say what is it - metaphysically - that is doing this choosing and pointing. Why do we ever feel like there is a "now" moment?

I believe the most popular way to understand spacetime is to just consider the future and the past to exist at all times (so to give a simple ontology for the relativity of simultaneity), and in such case all the states of the brain exist "all the time", and metaphysically there is no such thing as "now moment" at all except for our subjective experience. This is why Einstein said "time is just an illusion" etc...

But this view fails completely to account for what is it physically, that causes the "now moment" to exist in subjective experience. It must be something in the physical world causing this, yes?

For these reasons, I must consider the possibility that it really is "motion" instead of "time" that exists metaphysically. It is often stated that "for there to be motion there needs to exist time", but this is immediately invalid argument, because the semantical concept of "time" is what is derived from the fact that we observe motion. If things really are in motion and there really exists only present (not the past and the future), it would readily explain why the sense of "flow of time" exists in our subjective experiences.

Note that even if you consider it to be "time pointer" that "flows" in spacetime to give us the experience of "present moment", it is not meaningful at all to give any "speed" to this pointer. Regardless of its speed (or direction) through the static spacetime, the subjective experience "at the pointer" would be the same (for our sense of time depends on how reality is expressed physically in the brain). It is probably this fact that gives people confidence to the idea that time does not flow at all, but we should not forget that we would still need that "pointer" to exist, otherwise we have not given any explanation about why there is any subjective experience at all, and to me this just shows how the idea of time as a dimension is a non-sensical one and doesn't fit very well to ontological reality, even if it's a handy tool.

Consider the difference between "describing the motion of a physical system in an instantaneous manner, such as the brain in spacetime, and really experiencing the motion of a physical system; such as having a subjective experience. Consider this thought experiment:

If you take a snapshot copy of a physical brain and freeze all its motion (by some magic), does it still have a conscious experience of everything being still? No, for this would require thoughts (about stillness) to exist above physical motion.

If you wait for 10 minutes and take a snapshot of the state of the original brain, and modify the copy-brain manually into the same state, you have essentially inserted all the memories from that past 10 minutes into the brain, and if you now set the copy into motion, it surely would claim to have had a subjective experience of the past 10 minutes as if time was flowing smoothly.

But can conscious experience exist if time moves ahead in discreet steps? What if you do NOT set the brain into motion, but instead just project a new state onto it every 10 minutes? Would it still have a conscious experience of a smooth flow of time? What if you project a new state onto it once every year? Could you imagine the possibility, that while reading this, your experience right now of "this moment" is not real but is instead one that is "going to be updated into your brain a year from now"?

I think the more you think about these issues, the more inclined you become to consider the possibility that it is in fact motion that really exists, instead of a static spacetime block.

-Anssi

kvantti

Sep28-06, 08:37 AM

So you could say my belief is that we just haven't figured out the proper model yet, but that we are capable of doing so by letting go certain particularly sticky assumptions about reality.

That is possible.

When you say "when this happens continuously", are you not invoking an idea of motion? (For there is no sense of something happening continously without pointing out continuous "moments" from spacetime)

Well, spacetime is a continuum, so even if there is no motion, there is continuity. We observe this continuity as motion.

Why do we ever feel like there is a "now" moment?

Because we experience the increase of entropy in the brain as "flow of time" and "now" is just an illusion of this process. Try to remember what you did 0,1 seconds ago. Confusing?

For these reasons, I must consider the possibility that it really is "motion" instead of "time" that exists metaphysically. It is often stated that "for there to be motion there needs to exist time", but this is immediately invalid argument, because the semantical concept of "time" is what is derived from the fact that we observe motion. If things really are in motion and there really exists only present (not the past and the future), it would readily explain why the sense of "flow of time" exists in our subjective experiences.

You don't need to derive "time" from the concept of motion. You can just say that "time is a thing that enables the state of a system to change". But then again, a state of a system cannot change without motion. :tongue:

Note that even if you consider it to be "time pointer" that "flows" in spacetime to give us the experience of "present moment", it is not meaningful at all to give any "speed" to this pointer. Regardless of its speed (or direction) through the static spacetime, the subjective experience "at the pointer" would be the same (for our sense of time depends on how reality is expressed physically in the brain). It is probably this fact that gives people confidence to the idea that time does not flow at all, but we should not forget that we would still need that "pointer" to exist, otherwise we have not given any explanation about why there is any subjective experience at all, and to me this just shows how the idea of time as a dimension is a non-sensical one and doesn't fit very well to ontological reality, even if it's a handy tool.

Consider the difference between "describing the motion of a physical system in an instantaneous manner, such as the brain in spacetime, and really experiencing the motion of a physical system; such as having a subjective experience. Consider this thought experiment:

If you take a snapshot copy of a physical brain and freeze all its motion (by some magic), does it still have a conscious experience of everything being still? No, for this would require thoughts (about stillness) to exist above physical motion.

If you wait for 10 minutes and take a snapshot of the state of the original brain, and modify the copy-brain manually into the same state, you have essentially inserted all the memories from that past 10 minutes into the brain, and if you now set the copy into motion, it surely would claim to have had a subjective experience of the past 10 minutes as if time was flowing smoothly.

But can conscious experience exist if time moves ahead in discreet steps? What if you do NOT set the brain into motion, but instead just project a new state onto it every 10 minutes? Would it still have a conscious experience of a smooth flow of time? What if you project a new state onto it once every year? Could you imagine the possibility, that while reading this, your experience right now of "this moment" is not real but is instead one that is "going to be updated into your brain a year from now"?

I think the more you think about these issues, the more inclined you become to consider the possibility that it is in fact motion that really exists, instead of a static spacetime block.

I have thought the same from the perspective of the multiverse. In the multiverse, the quantum states of the universes actually are "snapshots" from the point of view of the observer. Every possible snapshot exists and these snapshots are connected with each other with the laws of nature. That is, when you have quantum states A and D, you can't get from A -> D without going thru B and C first. Same with the quantum states of the brains. The quantum states are seperated by Planck times (the multiverse is a discrete system). This accounts for "continous" conscious experience aswel.

So, again, I see no problem from the perspective I see things. :wink:

AnssiH

Sep29-06, 03:25 AM

Well, spacetime is a continuum, so even if there is no motion, there is continuity. We observe this continuity as motion.

Because we experience the increase of entropy in the brain as "flow of time" and "now" is just an illusion of this process. Try to remember what you did 0,1 seconds ago. Confusing?

The question is how is it that we experience an increase of entropy as flow of time? Perhaps this has more to do with relativity and philosophy than with QM, but nevertheless, the important point to pick up is that it is not really a satisfying explanation to say reality is a static spacetime block where nothing moves (where the whole concept of "now" is non-sensical), and that it is the continuity that we observe as motion. Of course I understand how this continuity describes motion, but that is not the same as really producing an experience of motion.

For reality to produce an conscious experience of motion, something in physical reality must be different "now" from "a moment ago" (even if these are misleading concepts).

Consider your own subjective experience. You have an experience that "now" is different from "yesterday", and surely your subjective experience is caused by something that exists in reality? Something "real" is causing your experience, right? Surely then something in reality is in different state "now" than it was "yesterday". Even if you consider yesterday still exists in spacetime, you need that pointer to experience the "now". It is not possible that in reality absolutely NOTHING is in motion or changes, because that would require your subjective experience to be something that is not part of reality.

So what I'm saying is that if you believe there is a spacetime, you have to commit to this idea absolutely before it is a valid ontological interpretation, and in that case you lose all sense of motion from reality, UNLESS you posit there is also pointer that moves in spacetime (so to make difference between today and yesterday for a given subjective experience), which then again is in conflict with the idea that there is no motion, but only a spacetime.

And to postulate that spacetime is static but pointer is in motion is not very elegant; why would there exist both, metaphysical motion and spacetime?

You don't need to derive "time" from the concept of motion. You can just say that "time is a thing that enables the state of a system to change". But then again, a state of a system cannot change without motion. :tongue:

Yeah, that's the problem. Sure, it is not readily given that time is derived from motion, but what is given is that we can only expect to have either real time-dimension or real motion, but not both.

If we choose it is time dimension that exist, then the problem is, like you said, the state of the system cannot really change without motion. Of course the only system we really know to exist "in motion" is "subjective experience". Can it be different from one moment to the next if there is no motion?

But if we choose it is motion that exists, it becomes little bit clearer. We stroll around the earth and observe motion. We may notice that each time a pendulum swings, our heart beats exactly 4 times, or a rotating wheel does exactly 5 revolutions. So we assume the "time" it takes for the pendulum to swing is constant (at least as compared to all the other physical systems around us).

So just now, by comparing the motion of different systems we have built a concept of time, and we might say "I'll run around the building in 50 pendulum swings". This doesn't mean there had to be "time dimension" underneath it all to make this running possible, for we could expect "motion" to be something that "just exists" in a fundamental sense. (Albeit it is still non-sensical to talk about the "speed" of this fundamental motion)

I have thought the same from the perspective of the multiverse. In the multiverse, the quantum states of the universes actually are "snapshots" from the point of view of the observer. Every possible snapshot exists and these snapshots are connected with each other with the laws of nature. That is, when you have quantum states A and D, you can't get from A -> D without going thru B and C first. Same with the quantum states of the brains. The quantum states are seperated by Planck times (the multiverse is a discrete system). This accounts for "continous" conscious experience aswel.

Does there exist a metaphysical "now" moment in MWI, or is reality still a set of static spacetime blocks?
If its latter, you still need something to change when subjective experience does.

kvantti

Oct1-06, 10:44 AM

The question is how is it that we experience an increase of entropy as flow of time?

I can't help but repeating myself: it's an illusion. The way we experience "the flow of time" is the only way we can experience it. For example, when your reading this text the entropy of your brain increases when it records the information you're reading. Because of the information your brain has recorded you have more memories of events, like reading this text. This gaining of new memories increases the entropy of your brains and gives an illusion of "flow of time". The fact that we experience "a present moment" is due to the fact that we can't remember the future; your brains haven't yet recorded future events. When the future events are recorded, you experience them as being in the "present" and after that, when your brains have recorded more events, in the "past".

For reality to produce an conscious experience of motion, something in physical reality must be different "now" from "a moment ago" (even if these are misleading concepts).

Something is different between "a moment ago" and "now" (from the perspective of subjective experience): the amount of information stored in your brains.

Even if you consider yesterday still exists in spacetime, you need that pointer to experience the "now". It is not possible that in reality absolutely NOTHING is in motion or changes, because that would require your subjective experience to be something that is not part of reality. So what I'm saying is that if you believe there is a spacetime, you have to commit to this idea absolutely before it is a valid ontological interpretation, and in that case you lose all sense of motion from reality, UNLESS you posit there is also pointer that moves in spacetime (so to make difference between today and yesterday for a given subjective experience), which then again is in conflict with the idea that there is no motion, but only a spacetime.

You don't need a pointer. The "now" is at every point of spacetime. The "nows" of your brains (and thus your consciousness) just differ from each other.

Of course the only system we really know to exist "in motion" is "subjective experience". Can it be different from one moment to the next if there is no motion?

Yes, it can. You just have to keep in mind that "subjective experience" is determined by the amount of information you have acces to and while the amount of information in your brains increases, you experience time "flowing".

But if we choose it is motion that exists, it becomes little bit clearer. We stroll around the earth and observe motion. We may notice that each time a pendulum swings, our heart beats exactly 4 times, or a rotating wheel does exactly 5 revolutions. So we assume the "time" it takes for the pendulum to swing is constant (at least as compared to all the other physical systems around us).

So just now, by comparing the motion of different systems we have built a concept of time, and we might say "I'll run around the building in 50 pendulum swings". This doesn't mean there had to be "time dimension" underneath it all to make this running possible, for we could expect "motion" to be something that "just exists" in a fundamental sense. (Albeit it is still non-sensical to talk about the "speed" of this fundamental motion)

The problem with only three dimensions is that the state of a three dimensional space can't change unless there is time; you would have only static 3D space. So, if you wan't to describe events in three dimensional space you need to use time, and the time component can be described as an extra dimension, giving total of four spacetime dimensions.

Does there exist a metaphysical "now" moment in MWI, or is reality still a set of static spacetime blocks?
If its latter, you still need something to change when subjective experience does.

Nope, there is no "now" in the MWI. You could say that "reality is a static multispacetime block". This "multispacetime block" is the multiverse. This is a simplified way to see it and it doesn't describe all the properties of the multiverse.

AnssiH

Oct2-06, 05:02 AM

Hmmm, we aren't making much progress... Let it be said, that I used to think of flow of time as an illusion much like you describe. I understand why people think this way. But some philosophy reveals that this view is not unproblematic at all. You must dig way deeper to really see the problems, and in particular form strong understanding about how we comprehend anything with semantical concepts and how we build those concepts in a mechanical sense.

So, let's see if we can clarify this a little bit from another angle. I'll try to proceed with careful steps. It doesn't matter if we disagree or not after this.

This is certain; We cannot claim "time must exist fundamentally, because otherwise there would not be motion".

We cannot claim this, because just like we can assert that "time" is what exists fundamentally (without cause), we can assert that "motion" is what exists fundamentally. The choice between is - to an extent - arbitrary. Just because our comprehension is based on concepts and classifications of reality, and because we need to use the semantical concept of "time" to express motion, does not mean reality works with semantical concepts also. We are forced to invoke the semantical idea of "time" to talk about "motion", but motion can still "really exist" without any fundamental entity like "time" dictating this change.

Otherwise we could also say that "numbers" or "vectors" must exist fundamentally, claiming that without numbers and vectors there could not exist "clusters of bananas" or "velocity addition", etc... Just that we need some concept to express something in reality doesn't make it of fundamental existence. (Note that any conscious experience is also a case of expression of reality, caused by the brain)

So we can establish that the choice between "time" and "motion" is somewhat arbitrary. Still agree?

Another thing that is almost certain is that "fundamental time" and "fundamental motion" are mutually exclusive; both cannot be fundamental.

I say "almost certain" because it is conceivable to imagine that time exists as a static dimension and it is read by a pointer/worldline that moves. It's conceivable but not very elegant, for various reasons.

If anything is allowed with motion, we could just as well expect it is the physical things, on which our subjective experience is based, that are in motion. If nothing is allowed with motion, this would include our subjective experience which certainly is "something". And more importantly, once we have described the structure of spacetime, our semantical concept of "motion" (of worldline) becomes meaningless as an explanation to the change in the subjective experience. The subjective experience could not detect which way this "motion of worldline" happens, because the worldline is not a homunculus entity (it is not "fundamental consciousness"). This well-known argument about the static existence of spacetime actually puts fair amount of mud on the idea that "time" is a prerequisite of motion.

So, to get any further with the issue, we must assume that "time" and "motion" cannot BOTH exist as fundamentals. Still agree?

At this point, people who have chosen the path of "fundamental time", are forced to resort to the claim that the flow of time in subjective experience is "an illusion". This they justify with the comfortable fact that reality is just an expression of the past in the brain at any given moment. But this claim does not so much explain anything as it ignores the problem. None of the states of the brain would be more "real" than any other state, yet in subjective experience one is, at a time, more real than others. Clearly this needs more words.

And here we get to the hard parts. It is difficult to explain it all briefly, but I'll try.

The issue is not so much about "how the expression of reality exists at any given moment", but to explain how is it that within subjective experience there is motion, if "nothing is allowed with motion". It is one thing to imagine the whole spacetime history of a brain, and another to understand a process of conscious experience occurring to that construction. When you have assumed that it is time that exists fundamentally, ontological descriptions of reality tend to get very muddy very quickly.

Considering the philosophy of the mind, it quickly becomes clear that it's better to understand consciousness in the sense that we are NOT conscious of "successive moments", but rather we are merely conscious of the "change" that happens. This becomes concrete in many cases. Any sensory stimulation must have a spatial AND temporal aspect to it before you can be conscious of it (the patterns in the neurons must actually change). The semantical concepts our brain builds are always juxtapositions of each others (They make sense without "fundamental meaning" only because there are "differences" to them; something is what something else is not). In many many ways, our subjective experience is about change, and for this reason it is absolutely impossible to really comprehend anything without invoking an idea of motion or change. You simply will not be able to describe subjective experience without invoking some idea of motion or change at some point. We are so used to change, that sometimes it takes considerable effort to just notice this conflict.

To say "...the entropy of your brain increases..." is invoking an idea of motion. To say "...the fact that we experience 'a present moment' is due to the fact that we can't remember the future" is invoking an idea of motion; it suggests one to imagine a metaphysical "moment" that is "real" at one particular "instant" but not at another instant.

At the face of it this all may seem like an indication that "time" could really be what exists fundamentally, just beyond our comprehension, but as you get closer and closer to understanding "static time" in an absolute sense (as in there is no motion anywhere at all), it merely clarifies the fundamental aspect of the problem of change within our subjective experience.

Subjective experience is caused by reality. Agree? If nothing changes in reality, nothing is causing change in subjective experience. This looks like a dead end.

Although, like I said, the correct choice between "fundamental time" and "fundamental motion" is not given. It could still be either one. But what is given is that if you build your model of reality around fundamental motion, things get very much clearer (Albeit any ideas about the "absolute speed" of that motion are still non-sensical).

And with current empirical knowledge, you can choose to do that. Like I said, it actually is NOT at odds with relativity, because relativity does not allow for direct observation of relativity of simultaneity. You can understand all the observable time effects as different relative speeds of the physical motion/processes (in different environments), although the more "descriptive" way to express this mathematically is probably much less elegant than Lorentz-transformation (Mathematical elegance is different from ontological elegance).

We still need to use the concept of time to "comprehend" motion semantically (to express it), but we must understand that it really is just a semantical concept, and reality does not work on semantical concepts. It just works under some fundamentals, of which we try to make sense by building semantical models of reality, that are always incorrect to some extent, because they are merely an expression of the real thing. Map is not the territory.

I hope that was not too confusing. It really is difficult to be brief with such a massive subject as this.

kvantti

Oct2-06, 05:36 AM

Hmmm, we aren't making much progress...

Yeah and I think I know why: you see things from a Newtonian point of view while I see things from the point of view of relativity. This conversation would go on and on without progress, because we just see things too differently. You see problems where I don't and vice versa.

I'm too tired to answer your whole post at the moment, I had three hours of sleep last night, and now I'm off to take a nap. Be back later etc.

AnssiH

Oct3-06, 01:19 PM

Well I guess then we are just going to have to disagree.

Although, if you find the reality of static spacetime likely, why do you consider MWI to be simpler than this:

http://www.physicsforums.com/showthread.php?t=130623

Isn't it simpler to just assume that light (and everything) exists in spacetime in static sense just the way we find it to exist, instead of imagining a model of many worlds that would produce the same behaviour? After all, you have to think about the trajectory of light as "single object" in spacetime, then why couldn't it exist fundamentally just the way we find it?

kvantti

Oct4-06, 06:01 AM

Isn't it simpler to just assume that light (and everything) exists in spacetime in static sense just the way we find it to exist, instead of imagining a model of many worlds that would produce the same behaviour? After all, you have to think about the trajectory of light as "single object" in spacetime, then why couldn't it exist fundamentally just the way we find it?

That is basically same as saying "we don't know how things work, they just are the way they are". The static spacetime approach doesn't explain why we observe the world as indeterministic even though it should be deterministic from the point of view of a static spacetime.
The MWI is the simplest physical interpretation for explaining quantum mechanics. This is a fact. People don't see this because the change in paradigm is so huge, so incomprehensible, that they reject it straight handed. But the fact is that the MWI is a consequence of a very simple postulate: the mathematical formulation of QM describe the behaviour of a quantum mechanical system; not just probabilities of different behaviours (as in Copenhagean). From this postulate emerges the whole idea of the multiverse.

I like to think that the mathematical formulation of classical mechanics describe the way macroscopic systems behave. Same with quantum mechanics.

AnssiH

Oct4-06, 11:44 AM

That is basically same as saying "we don't know how things work, they just are the way they are". The static spacetime approach doesn't explain why we observe the world as indeterministic even though it should be deterministic from the point of view of a static spacetime.

Well it's true that spacetime interpretation doesn't say anything about the indeterminism by itself (although it probably would be quite trivial to make all kinds of assertions about it that would be basically impossible to confirm), but as of the "we don't know how things work, they just are the way they are", that is the case with all models. Especially when we talk about ontological interpretations, they are literally just cases of selecting different "things" to exist fundamentally (like multiverse). This is what I critizised earlier in this thread and I certainly don't see reason to commit to any particular selection of "fundamentals".

The MWI is the simplest physical interpretation for explaining quantum mechanics. This is a fact. People don't see this because the change in paradigm is so huge, so incomprehensible, that they reject it straight handed.

Well I personally don't have any problems in making paradigm shifts, since I am convinced that any worldview that we are capable of is essentially a circle of beliefs; not fundamentally attached to any sorts of truths. And for the same reason I think it is just wrong to encourage anyone to commit to any interpretation, and whatever interpretation is the "simplest" really depends on what sorts of problems you are tackling (and to an extent how familiar you are with some interpretation).

For example, earlier you mentioned that Deutsch challenges doubters by asking "where else do the calculations happen if not in other worlds since there are too many degrees of freedoms for one universe" (or something like that). This particular idea about how many degrees of freedom there are is assuming that a photon experiences one particular moment in a newtonian way (in which moment there are this or that many degrees of freedom). But it is not very difficult to understand the same system as if the photons bouncing "back and forth" in spacetime are affected by the "future" measurement of each others. The degrees of freedom all exist in single universe now, but it doesn't really make sense to say that the calculations happen in many worlds anymore. At any rate, the observable behaviour of the system is the same in either cases. This is true for any model; you can always build arbitrary number of mechanisms to explain any behaviour.

But the fact is that the MWI is a consequence of a very simple postulate: the mathematical formulation of QM describe the behaviour of a quantum mechanical system; not just probabilities of different behaviours (as in Copenhagean). From this postulate emerges the whole idea of the multiverse.

I believe this postulate would hold true for spacetime interpretation too...(?) The critical difference seems to be different terminology and different concepts to refer to time, and that with spacetime interpretation the idea about information transfer is different from "just particles"; it is rather a connection over all space in one universe instead of series of lines in many universes. Very similar, but so very different... :I

kvantti

Oct4-06, 02:42 PM

AnssiH

Oct5-06, 05:05 AM

-- but as of the "we don't know how things work, they just are the way they are", that is the case with all models.
No, it isn't the case with all models. Some interpretations explain the physical behaviour behind quantum mechanical phenomenon, others don't.

It is the case with all human models about anything at all, not just QM interpretations. This is just elementary philosophy. A model is a set of "fundamentals"; something that is not caused but "just is" (and from which all the observable phenomena spring).

In the case of MWI, it doesn't explain how multiverse exists, it doesn't explain how photons exist, it doesn't explain why the universes affect each others the way they do. It says "they just do", which is what any other model says about their fundamentals.

Any explanation of any physical behaviour is at the bottom of it all an assumed set of fundamentals that are "not caused".

You can argue that some models explain more with simpler elements (note the history of the models of an atom, or the evolution from geocentric model of universe to heliocentrism to current ideas). Can we say that MWI explains more with less? How do we even measure that its fundamentals are simpler than those of other models? The meaning of "simplicity" is not unambiguous here.

And also, how can we make sure that MWI doesn't break reality into too small pieces? After all, it posits all this happens by things that we cannot directly observe, and these things also have functions that could also be broken into smaller and smaller elements. How do we judge where should the peeling end?

Also, any human idea is directly based on other ideas and vice versa, in a self-supporting fashion. This is why human understanding is "semantical" and capable of novel predictions. And this is also why any idea makes sense only if you have assumed a certain set of "truths". How can we measure that the particular set of assumptions - that make MWI possible - are true?

These are all important questions when we talk about ontology, and MWI is ontology more than "just physics".

And these above issues need to be understood at much deeper level than most people do. Most people do not appreciate what it means to claim something is "true". Even "true" and "false" are metaphysically non-sensical concepts, and I don't mean this in a naive way of "we cannot really know if this or that is true", but I mean the very method of classification of reality into "fundamental elements" is the only method with which an animal can make any predictions about its environment, but it is also always an arbitrary form of expressing reality. In many concrete ways that are not readily appreciated, just looking at an apple is a case of believing there is an apple there. Because you can only be conscious of your worldview, not the reality directly.

So, I just see it happening all the time that people assert something they believe in as "undeniable truth", without understanding it is undeniable only in so far that some other assumptions in their particular worldview are true. If the existence of god has been an undeniable truth your whole life, your proof of this is that world exists (for it could not without "the creator"). And it is fairly easy to see the circular fashion of the logic behind intelligent design, but all models are fundamentally like that. This is a restriction of semantical understanding.

The multiverse is a direct consequence of the postulate, not some tought up concept.

Even when the postulate is that the formulation describes directly a QM system, you still have to interpret what are the fundamental elements whose behaviour the formulation describes. This is nothing more than an interpretation. In spacetime interpretation we could also say that the formulation "describes directly what really happens". Now, I hear you when you say "it is not the probabilities that the formulation describes", and I tend to agree; copenhagen says too much and is probably incorrect. But MWI doesn't make anything fundamentally differently; it just posits "these are the things that exist" and draws a relationship between those things and the mathematical formulation about the observable effects.

So I don't know how you can claim MWI is not a thought up concept. It includes many many many assumptions that it holds true, before it can get to the final conclusion about many worlds. I know this automatically because human thinking is like that. This should not be too difficult to see.

(And this is why it is immediately erroneous to claim that a working quantum computer proves MWI. Just because you understand its behaviour by the assumptions made by MWI doesn't mean it cannot work in any different fashion)

I'm not encouraging anyone, I'm stating a fact. The Occams razor decides which interpretation is the simplest.

This is what I'm talking about. Little bit more philosophy into the picture please. Just what do you think are facts? And do you understand that Occam's razor can also be used by anyone just the way they please? I could say that by the Occam's Razor, I wish to cut out the many worlds and just have the one we can actually remember. And when you ask me to explain QM behaviour in single world, I can just claim that the nature of light, and everything, "just fundamentally exists" in advanced & retarded sense, until there exists a thermodynamically irreversible event. All I've done is selected another arbitrary set of fundamentals and no natural observer can demonstrate the difference.

It doesn't matter which quantum effects the quantum computer uses to calculate, photons or molecules, but it matters that a qubit can be in a superposition of state, ie. in the states |+1> and |-1> simultaenously. Either you interpret that qubits are in these states simultaenously in one universe or that they exit in only one state in one universe and in the other state in another universe, and that these universes superpose if the qubits are in decoherent state.

...or you look at the nature of light and matter completely differently; i.e. understand their existence with different underlying concepts. (Note; this is not a hidden variable idea. This says more about reality than some hidden variable theory. It mostly says a photon is a particle as much as a rainbow is an object)

In the end I just want to stress that I am not refuting MWI as invalid, but I am very very worried about people getting emotionally attached to different sorts of models too much, and not really understanding why any model is necessarily just an arbitrary set of fundamentals, and cannot directly be shown true by the very nature that these models exist. For as long as you do not appreciate this fact, you do not abide to scientific philosophy, but to religious philosophy. You can never truly "unlearn" whatever set of assumptions holds your worldview together until you understand just how does your worldview exist. And if you can't do that, your thinking becomes rigid (and breeds reptiles of the mind, as Blake puts it ;)

kvantti

Oct5-06, 05:28 AM

AnssiH

Oct6-06, 02:22 AM

There is a fine line between a model that describes phenomenon mathematically and a model that explains phenomenon physically.

If I would have to teach quantum mechanics, I would probably do it without intepretations. But then I'm basically just teaching the maths behind it.

I'm pleased to hear that. Although, I guess it is also important to say something about different interpretations, just not in too "factual" fashion. It should be stressed that it is pushing the conversation towards philosophy, and then you have to take into account the knowledge about knowledge.

Occams razor:
a model that is based on fewer assumptions, and gives the same experimental predictions as some other model that is based on more assumptions, is the simpler model out of the two and should be used to explain the phenomenon. In other words: the simpler the model, the better.

How can you interpret that in many ways? It may be that the MWI isn't the right approach to reality, but at the moment it is the simplest way to explain the quantum mechanical phenomenon. So if you don't want to set [model = reality], you can just say that "particles behave as they would behave if they would travel along every possible path from A to B."

Yeah, that's what I oftentimes say, and even then I stress that it may be there are no particles in existent during the travel since we only see the reaction of the atoms. There are all kinds of paradigm shifts conceivable that could change the picture considerably, but still keep the same observable effects.

And about occams razor, I do think it has got some merit, but at some point it becomes unambiguous just what is considered the simplest model; it depends on how you judge "simplicity" or "elegance".

For example, when people believed that earth is the center of the universe and all the planets and stars go around it, this was not just because of religious reasons or natural arrogance of man to place himself in the center of the world. This was because if you look up into the sky, the planets really do go around us!

So, the geocentric model was the one to choose. I'm not saying it was a stupid model at that point in time; it was the right one to choose from the experimental data, but it was a grave disservice to science to shut out alternative models.

There were experts who spent their whole lives studing geocentric model and attaching other models on top of it so that it was the basis of considerable amount if scientific models. When it turned out that every once in a while some planets move backwards for a while, their minds were so rigidly set into the geocentric model (which explained so much) that they thought the simplest way to explain this retrograde motion was to assume that some planets move in a figure of eight instead of in circles; that they perform a little backward orbit every year which to us looks like they go backwards. (You could for example posit that there are invisible planets rotating to opposite directions whose immense gravity causes the figure of eight)

And if you look at it, and you happen to assume geocentric model is true, you could validly argue that it is the simplest way to explain this. "We cannot just throw a wonderfully elegant geocentric model away due to one little observation; the model explains so much. The retrograde motion proves there are dark planets causing the figure of eight orbits"

And the way that progress happens is that the society unlearns; the old experts just die and young guns who have not invested into the old models perform a paradigm shift and decide heliocentric model is the way to go, albeit it means much of the investements of the previous generation need to be thrown away. This cycle is very natural to human thinking, and there likely are many kludges in modern models similar to "figure of eight orbits".

It has been observed that in very large galaxes the outer stars do not abide to newtonian law of gravity: "every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them."

Namely, the outer stars move faster in their orbits than they should if they were to remain on stable orbits. This is now "proof" that there is invisible matter outside the galaxy pulling the stars (decided my Occam's razor), just like the retrograde motion was a proof of figure of eight orbits. The reason this is a proof is that Newton's law is "obviously true".

But it is not particularly hard to form a simple modification to the newtonian law that would claim that at large distances the gravitational pull does not fall down "proportional to the product of their masses", and considering the possibility of quantum nature of gravity, it is kind of reasonable to expect there could be this sorts of effects.

The important question is; how do you really judge which one is more elegant way to go? To decide that the law of gravity is correct and thus there is invisible matter between galaxies, or to perform a deeper paradigm shift and look at gravity in a completely new way?

So, again, I'm not saying that the idea of dark matter is "definitely wrong". I'm just asking why do we consider it to be by far the most likely model?

Btw, I'm pretty pleased that the concept of "dark energy" is so vague about the nature of it; it implies that some sort of paradigm shift to gravity may well be in order, and the same paradigm shift could well place the idea about the birth of the universe (in big bang theory) into completely new light also.

All in all, the history of science is pretty fascinating thing, and looking at the way that scientific progress has happened in the past implies a lot about the modern theories and hopefully shows people better ways to recognize validity and invalidity between different ideas.

One fascinating pattern is how we have step by step placed ourselves further and further away from some priviledged position within the universe. Even now, although we do not consider ourselves to be at any sort of center point spatially, we kind of priviledge ourselves temporally; we think we exist very near to the birth of the universe, when other galaxies are still visible and so on... Investigating a paradigm shift where our miniscule view of the universe only seems to imply a nearby birth event (by its local behaviour) might just be fruitful. (After all, it is hard to substantiate the idea that in the beginning of spacetime there exist an event which marks the creation of the whole spacetime, the end and all. This, if anything, is placing semantical concepts into conflicting positions)

If only the current experts had not invested their whole lifes into the big bang theory... :I

Chaos' lil bro Order

Oct17-06, 05:55 AM

QM is flawed, is that a simple enough of a model for you?

rewebster

Oct22-06, 01:26 PM

QM is flawed, is that a simple enough of a model for you?

Aren't all theories flawed, then, as none are perfect (or totally accepted as the true theory)?

AnssiH

Oct22-06, 03:27 PM

QM is flawed, is that a simple enough of a model for you?

Aren't all theories flawed, then, as none are perfect (or totally accepted as the true theory)?

...yes... Let's try this one more time;

All models are descriptions of the behaviour of semantical objects, not "real" objects. All we can do is pick up stable patterns, classify them into "objects" (arbitrarily). And apparently then confuse that model with reality.

You cannot be aware of anything but semantical objects. Anything you can think of is something that exists in your semantical worldview. Don't forget this.

There will always exist a number of valid TOE's. Some may be more elegant than the others, but that too depends on how you measure "elegance".

rewebster

Oct22-06, 05:23 PM

AnssiH

Oct23-06, 12:41 PM

There will always exist a number of valid TOE's

See, this is where I disagree. I think there is only one valid TOE (which, I think, hasn't been realized as of yet), and, whether or not, one of the present theories is just incomplete to be valid as THE one and only TOE, or an as-to-be-found TOE.

I probably should have been more specific with my post. I meant it will always be impossible to make any explicit ontological interpretation of any TOE. You could come up with math that describes the whole universe accurately, but you cannot find out what is the "metaphysically correct" way to interpret that math.

I'm not saying this merely on the basis of there already existing a great number of QM interpretations with no way to explicitly choose which is the "correct" one. I'm saying this because any ontological description or any "way" to understand any system ontologically is an expression of how semantical objects interact, not how "real" objects interact, and if you follow my arguments in this thread (starting from the first one) you should be able to figure out just why we shouldn't expect any object we perceive to be "real" fundamental object in any metaphysical sense. Not photon, electron, or anything. We are merely describing stable systems. Imagining that waves are real objects, instead of stable systems.

rewebster

Oct23-06, 03:02 PM

AnssiH

Oct24-06, 07:23 AM

Labeling interactions and objects, perceived or not, is and, seems to be, one of the more complicating aspects with any 'system' (physics, religion, etc.) What is a 'real' object? What is a 'real' interaction?

A photo of a object or interaction isn't the object or interaction--it is a representation of that object or interaction. A person may be able to 'interpret' that photo of that object or interaction; but, it is still an interpretation--on a subjective level.

Exactly, but the case is also the same without any photograph; when the person is actually looking at some system right in front of him. Think about how reality is expressed in the brain in the form of semantical objects, and how we have built such semantical concepts as "interaction" in order to be able to predict how things unfold (this occurs for obvious survival reasons). Think about how this semantical expression really correlates to actual reality, and how our thoughts are and always will be limited to handle only semantical objects, and nothing more.

Like, let's talk about gravity. Any dog or a cat probably assumes that "things fall down", which is enough to make predictions about how something is "about to fall down from the roof onto my head". At all times "down" and "falling" and even "acceleration" (of that given object) are nothing but semantical concepts and the same situation can be described in many many different ways, so to come up with the same prediction that the object from the roof will hit you in the head.

That object can be a rock, or a block of ice, or a sack of flour. All these can be handled as a single object by the math (and also by the semantical mind), while in metaphysical reality they are nothing like that, they are just stable systems. Super-darwinism.

Or think about a doughnut. We see it as if it is the doughnut that is the object here, but we could equally well say it is the hole and the surrounding space that is the object, and doughnut is the shape that is "missing" from the object. Either way we are talking about semantics, and it is merely the intuitive usefulness of looking at the doughnut as "the object" and the hole and surroundings as "the space" that we tend to do that.

I think that is why math (in physics) and pure math is so well appreciated to some extent. It's hard to argue that 1 doesn't equal 1; but, anytime a representational object is exchanged for a numeric value, say, as in physics, such as t=t, which can become 3t=4t -1t, where t=time, an ambiguity can become incorporated where the interpretation is differing. Does having a '-t' mean, by some, that time travel is possible?

Yeah. It cannot be argued that 1 is not 1 because we simply decided it is so, and numbers are not entities floating around in reality either, they are tools which we use to classify reality, we can do whatever we want with them.

Like in the example with object falling from the roof, a mathematician could also produce the correct prediction in many different ways, and each of these methods would seem to imply something about reality. But we could not choose which of the methods corresponds to the way the event occurs in reality. (With further observations we could shut some ideas out, but we would also probably introduce a number of new ontologies into the picture at the same time)

Let's take another example. We can describe the motion of waves on a pond with math, and find out where they interfere and how. We could say from the math that there "must be waves that actually travel over the surface of the pond", and we can also imagine the wave as an object with identity in our head, but in reality nothing but a shape ever traveled over the surface, the water itself just went up and down.

Likewise we could use math to describe a path of a tornado or how two tornados affect the paths of each others, so to predict where the semantical tornados end up at, but even though the tornados affect each others, they are not "real entities", they are just stable patterns. And this is the case when we describe anything, even photons.

So, it would be a mistake to interpret any math as if it describes any real objects. It doesn't say how reality is. It just describes semantical objects, and it predicts how we will find the semantical objects to behave.

To me, that is one problem with MWI or string theory. It great for math and 'theory' (and maybe students like it for, it seems, lab time may diminished in that study area); but, labeling is extensive--and, therefore, interpretations of the 'labels' seems more varied--e.g. What does a membrane look like?

Yeah, I have found that philosophically less aligned physicists tend to make rather arbitrary assertions about reality without even realizing it.

We naturally ask ourselves questions like "what does an atom look like", while we also abide to a model where it is the "electron" that gives off a "photon" which is what reveals the shape of any "thing". Noticed the conflict yet? Noticed how, strictly speaking, the atom cannot really "look like" anything? I think I put it down quite clearly here:
http://www.physicsforums.com/showpost.php?p=925018&postcount=39
(The latter parts of the post, from "Or think about an atom. What does an atom look like?" onwards)

What is and, how many, interpretations can be made of even a 'real' particle?

I don't know, infinite number?

I'm not sure what you mean with "real particle" though. "Particle" is a semantical concept and QM phenomena quite explicitly shows they are not fundamental, but rather stable patterns/systems.

Stable pattern is handy as a semantical concept in that it allows the pattern to appear and disappear if the environment permits, like a tornado. Fundamental entity cannot do that unless we also imagine alternative dimensions where they go, like in MWI. It should have been clear when Einstein posited that mass equals energy, that mass really IS energy in stable interaction loop of some sort. It does not become "solid" in any real sense, it just performs certain functions which cause "solidity". If we find objects to disappear, energy has lost its structure, that's all.

And even when we talk about semantical electron, and even if it did not exhibit wavelike behaviour, could we really say that electron is a "real object", or is it rather that space is real and electron is a "hole" in it? Either way, we are juggling semantical concepts around, and reality does not work with semantical concepts, WE do, and we cannot get around that. Note how we are not only confused about reality of space & objects, but also time and motion... So very confused... :I

selfAdjoint

Oct24-06, 09:42 AM

Or think about a doughnut. We see it as if it is the doughnut that is the object here, but we could equally well say it is the hole and the surrounding space that is the object, and doughnut is the shape that is "missing" from the object. Either way we are talking about semantics, and it is merely the intuitive usefulness of looking at the doughnut as "the object" and the hole and surroundings as "the space" that we tend to do that.

It seems to me you're stretching the term semantics until it ceases to mean anything coherent here. If this figure-ground perceptive change is "semantics" then so are the different was of seeing the Neckar cube, or any optical illusion. I think, haveing spent a lot of time doing just this kind of mental gymnastics that my understanding of "semantics" just doesn't relate to what seems to me to happen in my head when I do that. But perhaps you have a ready answer?

rewebster

Oct24-06, 10:28 AM

In biology, labeling works; in that, gross characteristics are categorized into phyla, species, etc. It's when something out of the ordinary is found that questions whether, what and how to assign it (aberration or new species).

Physics is the same, it seems, to a higher factor. Some things are accepted and definable, while a lot of others are theorized upon due to the inability to exactly define it (them) with enough validity. Some don't/didn't see classic physics as the total answer, so 'this' and 'that' theory are brought into play each with their own set of definitions and labels about this action or that caveat, each adding to the confusion with even more labels. I think that that is why conversations about physics often times gets into philosophy and even religion (how many religions in the world are there?). Too many unknowns and too many opinions about the 'too many' unknowns---and, I think, that it will continue until 'things' are more 'known'.

AnssiH

Oct24-06, 12:59 PM

It seems to me you're stretching the term semantics until it ceases to mean anything coherent here. If this figure-ground perceptive change is "semantics" then so are the different was of seeing the Neckar cube, or any optical illusion. I think, haveing spent a lot of time doing just this kind of mental gymnastics that my understanding of "semantics" just doesn't relate to what seems to me to happen in my head when I do that. But perhaps you have a ready answer?

Yeah. Well, check out the first paragraphs of:
http://en.wikipedia.org/wiki/General_semantics

Perhaps I should talk about "general semantics" to cause less confusion, but I keep falling back to just "semantics" because language is so clearly just an instance of semantical understanding. Language is semantical because our understanding is semantical. And yes, just being conscious of holding a coin in your hand or seeing an apple in your visual view is a case of semantical understanding. I'll try to break it down and I hope I can demonstrate why it is important for a physicist to understand this.

Sensory data causes spatial/temporal patterns to occur inside the cortex. This is where different objects are being recognized. But what does it mean to recognize an apple? Does there exist a metaphysical "apple neuron" whose firing means an apple has been perceived? Of course not. You must have first assumed there exists such things as "apples" in the world. The brain must form a worldview, which is assumptions about "what exists" and assumptions about their behaviour.

How does this learning happen then? I could say the brain classifies objects by their properties, but that would already be wrong, in that it would imply there really exists metaphysical objects that can be classified. Oh no, the brain only finds stable patterns, and assumes there are objects. We do not point at an arbitrary portion of a wall and call it an object, we classify reality into, let's say "sensible objects" (Like what rewebster said about labeling things in biology).

All this labeling and classification of the sensory data occurs because that is the only way to find "things" that exhibit persistent behaviour, and when we find such things, we can perform predictions. The brain can basically simulate reality. It perceives some situation, it recognizes objects (rolling rock, gushing water, fog in the wind...), and it can form some idea about what is going to happen. (Rock coming down on you will harm you, water might too, but fog won't, unless if it might be nerve gas, etc...)

At no point of this learning we had any actual "knowledge" about reality in our disposal. How could we have ever learned that there exists "ground" when we did not know what any of the sensory data means at all, when we did not know what is "visual" data or what is "audio" and what is "tactile"? Well, at root, the worldview is self-supported circle of truth. All ontological arguments are circular. All views of reality are a set of self-supporting assumptions. Not only that, all things we could ever perceive and form any semantical ideas of, were patterns that were distinguished by their differences from each others. Air could not be perceived if everything was air. There must also be an idea of "ground" so to give any meaning to "air".

This is why all our conscious understanding is semantical. Nothing has any metaphysical meaning to itself, and nothing we are conscious of is "reality". It is merely something we have a semantical idea of, and the idea itself exists only on the virtue of other ideas giving it some meaning. We do not even have any visual experience without a semantical worldview against which to interpret the data.

This is imperative to understand, so let's still imagine a world where everything was completely red. If everything was red, we would have no comprehension about colours at all. The red world would not look like "red" looks to us currently. We would not be conscious of any "red" things. The way we experience red now is arbitrary. Reality does not look by its colour the way we see it; there just exists different wave lengths of light. We could not consciously perceive red without being able to tell what is not red; without other colours existing.

So, just being conscious of an apple moving across your visual view will require a good amount of semantical interpretation of the data to occur. When the apple moves, a corresponding pattern moves across the cortex and only at the upper levels it will be recognized as an apple, and only by the virtue of some semantical assumptions about reality it can be assumed to be the "same apple" from one moment to the next.

And because we understand reality in terms of sensible objects, we tend to make the error of identity. It is useful to assume the apple really is the same from one moment to the next, even though this is completely arbitrary assumption. We assume the apple has got metaphysical identity, and we have an experience of our "self" having an identity (which I is caused by certain semantical assumptions also). As we break reality down into smaller components, we find that things like shadows, rainbows and tornados do not really have identity; they are just stable shapes which consist of different "stuff" from one moment to the next. But we still make the same error and ask "so what are the fundamental things then?" We assumed reality was made of "water, ground, air and fire" because we saw it fit to assume things really have identity to themselves.

The answer I can give is that there never was and never will be any fundamental "things". Reality consists of self-organization and there comes to exist stable patterns which interact and form new stable patterns in emergent sense, and at some point along that road there comes to exist the stable pattern that is our semantical prediction process, which is stable in evolutionary sense BECAUSE it can actually predict reality before reality itself catches up.

Many materialists fall to this fallacy of identity as well when they posit our identity is the matter we are made of. Here we come to the mind-blowing parts of the nature of our "self".

I said objects are recognized in the cortex. Many people naively imagine that we are the cortex then; whatever happens to the cortex is what we experience. This is almost right but in some important ways not quite. The cortex is not a metaphysical object either. It does not have identity to itself. It is just stable system, where in some arbitrary sense we can say there occurs so-called "object recognition", but it is not the cortex having a conscious experience, for the cortex is a "colony of things", like an ant colony. How does a colony conceive itself as one and have just one subjective experience? Why don't every neuron have a subjective experience of "reality hitting them"? Or if they do, which one is our "self"?

Note that a single neuron does not build a worldview in any sense, it is the whole colony that does. A single neuron doesn't have a model of reality in it; the whole colony does (in some arbitrary form). And this is an important hint; the colony has, by its structure, made an assumption that there does exist such a thing as "self". This "self" is entirely a semantical token in the worldview, which consists of nothing but "assumptions". The colony conceives itself as one.

There are many neurons, but only one worldview, only one interpetation process, and consequently only one subjective experience (it is possible, and there are cases, where there basically exists multiple worldviews inside one brain, which is the same as many "minds" inside one brain, which in some cases are both active at the same time and are capable of independent attention, like in the case if Kim Peek)

Furthermore, here I claim, that for conscious experience to occur the "learning system" must make semantical assumption about there existing such a thing as "self", and consequently interpreting sensory data in semantical form of "I see an apple".

We never were and never will be aware of reality hitting our cortex directly, for it is not reality we are conscious of, it is the semantical objects and ideas in the worldview instead! Think about that.

But it is important to notice, as you probably have many times while reading this post, that when I use semantical concepts to describe the above, I am moving in circles, and I cannot actually touch the "true reality" of what happens. No matter in which form you imagine the worldview to really exist, you are at all times merely imagining bunch of SEMANTICAL THINGS that exist in different configurations. This can be useful, but it is not reality.

This is why I can never exhaustively convince anyone about the above being true. If what I say is true, I can never convince you of it! Ain't that a bummer... I can only say there exists overwhelming amount of indications towards the above, and it basically solves the hard problem of consciousness as good as it can ever be solved. Semantical idea of the system that causes those semantical ideas is never true to reality of the system itself.

But I've already said enough, if you are interested of philosophical side of it, try;
http://www.amazon.com/o/ASIN/0262633086/ref=s9_asin_title_1/002-7176880-1417620
(I still haven't had a chance to read this myself but I intent to, and judging from the first pages it is pretty spot on)

Or for mechanical side of prediction processes, try;
http://www.amazon.com/Intelligence-Jeff-Hawkins/dp/0805078533/sr=1-7/qid=1161711324/ref=sr_1_7/002-7176880-1417620?ie=UTF8&s=books
(This I have read, and what is described could well be what gives rise to such system that can produce semantics and semantical predictions the way I described)

Phew... That was long but now I hope I put everything I have stated before into rather coherent whole, and I can just refer everyone to this post when I make confusing statements about semantics elsewhere ;)

rewebster

Oct24-06, 01:22 PM

AnssiH --could you paraphrase your post #148?

Just kidding---

now, how do you relate all this to physics and 'realism' in physics?

rewebster

Oct25-06, 08:19 AM

DrChinese

We lost a couple of the last posts---

could you repost your answer about the photons and electrons?

DrChinese

Oct25-06, 09:10 AM

DrChinese

We lost a couple of the last posts---

could you repost your answer about the photons and electrons?

I'll come as close as I can. The question was whether photons are assumed in most posts about Bell's Theorem & entanglement.

Bell's Theorem itself used spin 1/2 electrons as the base example. But because photons are much easier to prepare, and because the resultant tests also can control for the locality assumption as well, photons are almost always used in experiments. I would say that most posts assume the discussion is about photons and spin. Technically, entanglement can be seen with other observables besides spin.

rewebster

Oct25-06, 01:20 PM

Well, I've thought about what I see could be problems; and, it is that it was first created as a thought experiment, right? It seems a lot of physics experiments do start that way. To me, the electrons probably wouldn't react in the experiment as a simple 'electron' as so much energy would have to be pumped into them, right?; and the testing in that way may make the experiment 'different'.

And as far as photons, does the test lean toward them being waves or particles? Does it matter? And since photons are still in the 'what is it?, a wave or a particle?', it makes the testing (with the filters) a little bit removed to, as least for me, to give any weight to the results.

The results of any tests, for me, have to be taken with a grain of salt. I like wondering how many assumptions are made, first, to bias the results.

AnssiH

Oct25-06, 01:50 PM

now, how do you relate all this to physics and 'realism' in physics?

Well the stuff about phenomenal self was just additional words to hopefully drive home how meaningful it really is to assume such a worldview where there does not actually exist any "fundamental entities". And if you can do that, it obviously does have an effect to questions about realism. Like I said early on in this thread, any form of semantical understanding (i.e. any human understanding) is at the end of the day "naive realism" in the sense that it must posit some fundamentals, and what we posit will always be - to an extent - arbitrary.

But still we keep forgetting this, and this is evident all over the place, including in the comment that Einstein made about reality of electrons, that "particle must have spin, location and so forth even when it is not being measured". He should have noticed our idea of electron exists due to certain ways we measure certain systems, and due to us imagining there really are such things as electrons causing the effects we measure.

I'll just copy-paste from my first post to this thread (#33):
Like Einstein noted himself; our comprehension of reality is based on certain assumptions about reality... ...But here he is making certain assumptions about the metaphysical identity of things. A realist doesn't have to assume that an electron has spin, a location and so on before being measured, because we can only measure things with pieces of matter, and thus these properties of electron, indeed the whole electron as we think of it, can be a result of interaction between the measurement device and something else that is not measurable as it is by matter.
(This touches little bit your above post too)

This doesn't mean we should assume our mind creates the illusion of electrons & reallity in idealistic fashion. It means we should not assume electron to be "real object" any more than a rainbow is "real object". Neither exists objectively "as they are observed" without the observer. The rainbow, as it is observed as a band of colours, is a result of interference on the observer, and it never could exist "independently".* There's no reason why electron, and everything, could not be like that. And in fact we should expect them to be like that. It's all just darwinism in extended sense.

Granted, with understanding QM there is the added complication of "semantical time"... :I

* If this doesn't seem to ring true, try to really pin down what is the location of a rainbow in an objective sense. The rainbow is certainly "real" in that everyone observe it, but can we say it is something that has independently got the properties that we measure? Like its spectrum and intensity and location? We can define rainbow in many different semantical ways, and say, for example, that it exists in the eye of the observer (where we can say what is its "real spectrum"), but then we don't account for other parts of the system that cause the pattern of rainbow (light and water droplets).

We could insist rainbow is a "real object", like we insist photons and electrons are real things, but if you assume this, your scientific explanation of the rainbow would have to include multiple dimensions where there exists multiple rainbows while we observe only one at a time. (Much like some people like to explain QM with many-worlds)

But it seems that the key to understand the reality of a rainbow or the reality of an electron is to perform such a paradigm shift where all the observed properties are just semantical properties of semantical things, and they are actually caused in part by the measurement device, and do not exist independently at all.