Had we already abandoned falsifiability?

[Dmitry67]

In 1915? (Schwarzschild's solution for the interior of the black hole)
But what happens inside the horizon is not falsifiable...

 

[russ_watters]

I think that as long as people recognize such things for what they are, it does not constitute an abandonment of falsifiability.

Basically, in this case, you would say: "The solution implies XXX, but we are unable to verify or falsify this." As long as no stronger statements are made in favor of XXX, it's fine.

 

[jambaugh]

In 1915? (Schwarzschild's solution for the interior of the black hole)
But what happens inside the horizon is not falsifiable...

This used to bother me too until I thought it out carefully and realized the following.

The inability to view the interior of a black-hole's event horizon is exactly the same as our inability to observer the future (without waiting for it to become now). In essence the interior is always in the future of events outside.

For all we know the gravitational constant will triple suddenly inside the future light-cone of the Earth at 12:01am EST January 1 2012. This is not falsifiable today but we can wait and see.

Likewise if you wish to disprove a hypothesis about the interior of a black-hole's event horizon you need only jump on in and check. The fact that you can't then tell me about it (since I'm not fool enough to follow you) is no different from the fact that you can't go back in time and tell Einstein what the stock market did today.

We use the same "faith" about no sudden changes in the laws of physics over time by which we project past evidence to future predictions, to also project beyond the event horizon of black holes.

 

[Dmitry67]

Well, there is a difference.

If I predict that tomorrow day will be 2 hrs shorter for mysterious reasons is falsifiable. Just wait until tomorrow. In fact, you can not provide any contreexample immediately for some theories, so you need to make an experiment - you need some time to prepair it. Even to provide a contreexample you already know from the past experience takes some time, you need to open your mouth and say some words.

So NOTHING is falsifiable IMMEDIATELY, in a t=0 interval.

But for the black hole you will NEVER know... This is a difference...

 

[DaveC426913]

Well, there is a difference.

If I predict that tomorrow day will be 2 hrs shorter for mysterious reasons is falsifiable. Just wait until tomorrow. In fact, you can not provide any contreexample immediately for some theories, so you need to make an experiment - you need some time to prepair it. Even to provide a contreexample you already know from the past experience takes some time, you need to open your mouth and say some words.

So NOTHING is falsifiable IMMEDIATELY, in a t=0 interval.

But for the black hole you will NEVER know... This is a difference...

I think he means "the future" in the strict metaphysical sense that "the future" is always yet to be, even if there are events in it that will become "the present".

i.e. we cannot know "an event in the future" until it stops being "in the future" and becomes "in the present".

I'm just not sure if that's a valid concept.

 

[jambaugh]

Well, there is a difference.

If I predict that tomorrow day will be 2 hrs shorter for mysterious reasons is falsifiable. Just wait until tomorrow. In fact, you can not provide any contreexample immediately for some theories, so you need to make an experiment - you need some time to prepair it. Even to provide a contreexample you already know from the past experience takes some time, you need to open your mouth and say some words.

So NOTHING is falsifiable IMMEDIATELY, in a t=0 interval.

But for the black hole you will NEVER know... This is a difference...

No there isn't. Again as you reiterated nothing is falsifiable immediately nor into the past. We are swimming in event horizons, the boundary between past and future is an event horizon. (or more properly the future light-cone of an event is an event horizon). It is the existence of these event horizons which prevents us verifying a hypothesis about the future without going there. Similarly you can go into the interior of a Black hole's event horizon and verify/falsify any prediction there. You just can't get back out.

A black-hole is simply a little ball of "always the future" for anyone outside it.

Now we can falsify Einstein's theory about local regions of space-time.

Having done so we can define hypotheses about local regions of space-time 100years in our future as likewise falsifiable via our ability to test them in the present. There is that implicit assumption that physical laws don't change over time (or better said we incorporate any change over time into our definition of "physical laws").

How is this different from a not-so-bright astronaut who is about to fall into a black hole assuming Einstein's field equations still hold in his future?

He will not see a sudden change in the physical laws at the event horizon any more than we see one as we cross the infinite pages of event horizons separating our past and future from moment to moment. Locally there is no distinction. They are of the same type. The only difference is that we outside see all those pages become a tube from our perspective. But the infalling astronaut doesn't see any substantial difference. At the instant he reaches the event horizon of the BH he sees it locally as a piece of his future light-cone.

Now granted near the singularity at the center all bets are off because we cannot locally replicate those conditions. But between there and the surface it's just space-time locally like any other piece of space-time.

 

[Dmitry67]

Ok, agreed, this is a good point. Still there is a problem

I agree that some suicidal experimenter can verify the laws of physics inside the black hole (any volunteers?). But the humankind will NEVER benefit from his research.

if we DO accept the falsifiability as an important rule, we should STOP all blah-blah-blah about the interior of the BH until... well, except for the kamikadze researches.

Just compare the status of the Higgs boson right NOW with the status of the Schwarzschild (Kerr) solutions of the interior of the BH.

Higgs: theoretical, we are almost sure, but it is not confirmed. So it is still a hypotesis because experiment has not been yet performed
Interior of the BH: Yeah, old well known, booooring stuff, check the book written in the beginning of the 20 century.

Now, we are going to know about the Higgs in about 1 year (I hope). Regarding the interiour of the BH, we will NEVER KNOW. So I ask you, how the status of these 2 HYPOTESIS can be so different? Nobody even calls the Schwarzschild (Kerr) equation a HYPOTESIS. It is called a SOLUTION. Feel the difference? :)

 

[Hurkyl]

Another thing to recognize is that science necessarily deals in extrapolation; if it didn't make any predictions about situations that have not been tested, then it wouldn't be very useful!

(Some extrapolations are so tame that many people have difficulty accepting that it's involved -- for example, the prediction that the sun will rise tomorrow -- but it's still an extrapolation!)

So the question boils down to what sorts of extrapolations are 'safe'. My understanding (I am not a scholar of GR) is as follows:

Space-time near the event horizon (both from the inside and from the outside) is predicted to be rather ordinary-looking, especially for a large black hole. It's only by looking at all of the space-time around it that you would notice anything unusual. And thus, there is little grounds for skepticism. In other words, the description of the interior of a black hole (at least, away from its singularity) appears to be that of known physics applied in its domain of validity.

 

[Hurkyl]

Nobody even calls the Schwarzschild (Kerr) equation a HYPOTESIS. It is called a SOLUTION. Feel the difference? :)

Of course. An object that satisfies an equation (or system of equations or other type of condition) is usually called a solution. And the Schwarzschild metric does indeed satisfy Einstein's field equations. (at least in the 0 \neq r \neq 2GM/c^2 region)

 

[jambaugh]

Of course. An object that satisfies an equation (or system of equations or other type of condition) is usually called a solution. And the Schwarzschild metric does indeed satisfy Einstein's field equations. (at least in the 0 \neq r \neq 2GM/c^2 region)

Right. Specifically the hypothesis is the field equations, or more precisely what they predict about trajectories of test particles, the solution is the prediction of the hypothesis.

Note on your qualifier, in appropriate coordinates the Schwarzschild solution is valid at the event horizon as well. You just get a coordinate singularity in the original form. We don't say for example that a solution to a well formed differential equation fails at r=0 just because we are using polar coordinates and thus there's a coordinate singularity there.

 

[jambaugh]

Ok, agreed, this is a good point. Still there is a problem

I agree that some suicidal experimenter can verify the laws of physics inside the black hole (any volunteers?). But the humankind will NEVER benefit from his research.

Again I can coach another "future hypotheses can't benefit humanity in the past" e.g. we will not today benefit from assuming Maxwell's equations will hold 100years from now.

But be that as it may. You say "never" but you can't rule out the possibility that at some time in the distant future a very large black hole won't swoop down and engulf the entirety of humanity in which case a.) we will be able to verify/falsify Einstein's theory in the interior and b.) it might be damn useful to know how long we got until the tides rip us apart.

For that matter there have been made serious conjectures as to whether the entirety of the visible universe might not be interior to a very large black hole.

if we DO accept the falsifiability as an important rule, we should STOP all blah-blah-blah about the interior of the BH until... well, except for the kamikadze researches.

It is an important rule but not to be used mindlessly. Its purpose in the tool bag of the theoretician is to excise non-operational hypothesizes (such as the existence of a luminiferous ether.) It is perfectly operational to discuss what our hypothetical astronaut would see as he passes into a BH. For this test of operationality it is sufficient that one hypothetical astronaut could in principle test it. Once we agree that this is the case then we needn't actually sacrifice such an astronaut nor require he have the ability to tell us what he's observed. We have shown the hypothesis is operationally meaningful.

Now actual experimental confirmation is another matter... but that is not what we are talking about.

We can test and falsify the implications of Einstein's field equations in any region of space-time. Once that has been done then extrapolating them to other regions of space-time, be they the interior of a black hole or the future, is perfectly valid and reasonable.

I think you would see this clearly if you understood better the nature of "an event horizon" and the equivalence in nature (if not shape) between the one around a black-hole and the one keeping me from telling my past self tomorrow's stock market summary.

I will also point out that you are guilty of your own "sin" in that you are making hypotheses about the interior of a black hole, namely that it is causally incommunicado, said hypothesis being by your arguments non-falsifiable.
( If anyone should "stop all the Bla Bla Bla"...)

 

[Dmitry67]

It is an important rule but not to be used mindlessly. Its purpose in the tool bag of the theoretician is to excise non-operational hypothesizes (such as the existence of a luminiferous ether.) It is perfectly operational to discuss what our hypothetical astronaut would see as he passes into a BH. For this test of operationality it is sufficient that one hypothetical astronaut could in principle test it. Once we agree that this is the case then we needn't actually sacrifice such an astronaut nor require he have the ability to tell us what he's observed. We have shown the hypothesis is operationally meaningful.

I agree with you. I even think that the importance of that tool is overestimated.

Max Tegmark used this example to illustrate that 'parralel universes' must have at least the same status as the interiors of BH.

In both cases we have gravity/QM operating smoothly Outside of the BH/In out branch of reality.

In both cases nothing magical happens on the Horizon/during the Quantum decoherence. Both processes are described mathematically.

So I can just replace few words in what you had said:

It is perfectly operational to discuss what our hypothetical astronaut would see as he passes into an alternative branch of reality. For this test of operationality it is sufficient that one hypothetical astronaut could in principle test it. Once we agree that this is the case then we needn't actually sacrifice such an astronaut nor require he have the ability to tell us what he's observed.

 

[jambaugh]

I agree with you. I even think that the importance of that tool is overestimated.

Max Tegmark used this example to illustrate that 'parralel universes' must have at least the same status as the interiors of BH.

In both cases we have gravity/QM operating smoothly Outside of the BH/In out branch of reality.

In both cases nothing magical happens on the Horizon/during the Quantum decoherence. Both processes are described mathematically.

So I can just replace few words in what you had said:...

Not so fast. First explain what you mean by "parallel universes" and explain how to go about getting your astronaut to traverse them. We know how to enter a black hole, you just fall in. If you're thinking of a Kerr black hole e.g. worm-hole then there are some issues about crossing the second horizon... but let that be.

But I am not arguing that we de-emphasize the importance of falsifiability. To the contrary, I would insist scientific hypotheses be operationally meaningful. Components which are not should be identified as elements of a model!


If you are thinking of something silly like Everett's many worlds then ... well I can say a lot (and have) about that. Everett's many worlds are by definition not operationally meaningful and thus should be called a Everett's many-worlds model instead of an interpretation.

Carefully re-read what I have said. I did not say that falsifiability should be de-emphasized but that it should be applied consistently and with its purpose (testing operationality) in mind.

 

[Dmitry67]

1
First explain what you mean by "parallel universes" and explain how to go about getting your astronaut to traverse them.

If you are thinking of something silly like Everett's many worlds then ... well I can say a lot (and have) about that. Everett's many worlds are by definition not operationally meaningful and thus should be called a Everett's many-worlds model instead of an interpretation.

2
We know how to enter a black hole, you just fall in. If you're thinking of a Kerr black hole e.g. worm-hole then there are some issues about crossing the second horizon... but let that be.

1 Well, in Everetts interpretation Many Worlds is an axiom.
I believe in a modern interpretation, Many Worlds based on the Quantum Decoherence
So the Many words are the consequence, not an axiom:

Max Tegmark
http://arxiv.org/abs/0704.0646v2

So in order to go into a parralel universe we need to do something different based on the random QM event. For example, if I see a dead Shroedinger cat, then another me is watching the alive one.

2 It is an offtopic, but could you explain or point to the right place... what are the problems with the second horizon?

 

[jambaugh]

1 Well, in Everetts interpretation Many Worlds is an axiom.
...

In which case his worlds are mathematical constructs and not physical per se...

I believe in a modern interpretation, Many Worlds based on the Quantum Decoherence
So the Many words are the consequence, not an axiom:
Max Tegmark
http://arxiv.org/abs/0704.0646v2

Again this "interpretation" is not operational and so should be called "model". I understand quantum decoherence...= irreversible entanglement with the episystem. I wouldn't call "many worlds" a consequence. There is still an implicit assumption=axiom. Decoherence does not contradict the Copenhagen interpretation so it can't be said to imply any other interpretation.

So in order to go into a parralel universe we need to do something different based on the random QM event.

Different from what? You are getting "entangled" in counterfactuals. The "you" that does "something" is distinct from the hypothetical " you' " who does "something different". The second can't communicate with the first any more than Tom Sawyer can communicate with me. Tom Sawyer is a fictional character, ...

For example, if I see a dead Shroedinger cat, then another me is watching the alive one.

And I assert that "No, a demon can see the future and picks the outcome to be consistent with QM's predictions and what he knows about future experiments on the quantum system ... just because he wants to be nasty...oh yes and he has big red horns and a curly black mustache". How is my hypothesis less non-falsifiable than yours?

The Everette many worlds model reminds me of the old song "I knew an old lady who swallowed a fly..." it tries to cure a minor unaesthetic issue by introducing a very inelegant "horse-sized" assertion.

2 It is an offtopic, but could you explain or point to the right place... what are the problems with the second horizon?

I have a vague recollection of there being a boundary of infinite temperature inside the Kerr black hole which must be crossed if you're going to avoid the singularity. This is to say no information could actually make it through even though there are classically causal paths through. I just did a google search and I think this is what is now referred to as the "blue sheet".

 

[Dmitry67]

=Again this "interpretation" is not operational and so should be called "model". I understand quantum decoherence...= irreversible entanglement with the episystem. I wouldn't call "many worlds" a consequence. There is still an implicit assumption=axiom. Decoherence does not contradict the Copenhagen interpretation so it can't be said to imply any other interpretation.

Well,

http://en.wikipedia.org/wiki/Quantum_decoherence

However, decoherence by itself may not give a complete solution of the measurement problem, since all components of the wave function still exist in a global superposition, which is explicitly acknowledged in the many-worlds interpretation. All decoherence explains, in this view, is why these coherences are no longer available for inspection by local observers.

So, after QD we have 1/2 alive cat + 1/2 dead cat. These cats don't interefere.

You have a choice: to assume that both cats do exists (Multiworlds), or to invent some new mechanism (like wavefunction collapse) to explain why the whole universe had randomly but consistently chosen one particular branch.

In that case you whould deal with the Ocamms razor (why do you need it if everything is already explained without it?) Your mechanism will be non local and you will have to answer questions like 'as QD is not immediate, at what moment the second branch dissapear? Why any particular branch is chosen? You say, randomly? What is a probability? Bayesians or Frequentisits? Why? et cetera, et cetera, et cetera...

And why? Why do you need all that weird stuff? Just because the very idea of parralel universes is so weird? because it is so easy to assume that space,or time are infinite, but for some reason we can not aqssume that WE exist in the infinite number of copies?

 

[jambaugh]

Well,

http://en.wikipedia.org/wiki/Quantum_decoherence


So, after QD we have 1/2 alive cat + 1/2 dead cat. These cats don't interefere.

You have a choice: to assume that both cats do exists (Multiworlds), or to invent some new mechanism (like wavefunction collapse) to explain why the whole universe had randomly but consistently chosen one particular branch.

In that case you whould deal with the Ocamms razor (why do you need it if everything is already explained without it?) Your mechanism will be non local and you will have to answer questions like 'as QD is not immediate, at what moment the second branch dissapear? Why any particular branch is chosen? You say, randomly? What is a probability? Bayesians or Frequentisits? Why? et cetera, et cetera, et cetera...

And why? Why do you need all that weird stuff? Just because the very idea of parralel universes is so weird? because it is so easy to assume that space,or time are infinite, but for some reason we can not aqssume that WE exist in the infinite number of copies?

No after QD you have either a live cat or a dead cat with classical 50-50 probability.

The "many worlds" are many worlds of possibility. Its no different from standard classical probability. If I flip a coin I can imagine it landing heads and imagine it landing tails... two worlds in my imagination. Afterward those two worlds still exist in my imagination but I qualify one as "what might have been". I don't need a fancy mechanism or to worry about "classical probability collapse" or anything. Both "worlds" continue to "exist" in my brain.
The actual coin behaves as it behaves and I observe it as I observe it.

In order to see actual quantum behavior for cats you must first freeze the cats to near absolute zero then you'll need a very large number of frozen cats so you can do interference experiments and get a whole interference pattern. Of course the cats can't survive such an experiment so "alive vs dead" is not going to be a quantum observable anyway. Remember a cat is a heat engine and thus any quantum interaction with them by definition must decohere almost immediately.

Let me put it (decoherence) another way. Think of entropy as entanglement with the environment. (Recall that partial traces of the zero entropy joint density operator yields a non-zero entropy density operator for a partial system.) Now once a quantum system interacts with its environment it can no longer be sharply described (i.e. with a wave-function) alone. It must either be described with a density operator or to preserve the sharp description you would have to describe the system plus that part of the episystem it has interacted with and then only if that part of the episystem has been observed sharply before hand. (That is unless you have been very careful with the type of interaction i.e. you've made a measurement or are preparing the system in a sharp mode). T

You in other-words would need to observe a cross section of the system's past light-cone up to the point you still want to describe the system sharply and likewise the future light cone of that whole system. And given that bigger system has also interacted with its environment...

If you do not do this then you introduce classical random variables into the system upon which the outcome of the future experiment on that system will depend. Thence the "collapse" of the system's wave-function is no different from the "collapse" in the expectation value for a lotto ticket once the drawing occurs, a classical probability collapse.

There is no problem to be solved by invoking Everett's many worlds. Wave function "collapse" is only a conceptual problem if you confuse the wave-function with the actual system. A lotto ticket is not the cash prize (or a superposition of many cash prizes). A wave-function is not an electron. Remember that quantum interference is more fundamental than classical wave interference. Classical waves are composites of quantum systems. Why go backwards and try to describe a quantum system as a classical wave (function)? Instead understand that the wave-function is a representation of what we know about how the system behaves.

With respect to the measurement "problem" and wave-function "collapse" consider this. The distinction between "before" and "after" is by definition separated by an environmental interaction. The variables describing the system "after" differ from those "before" said difference depending on the "in between" interaction which is necessarily probabilistic. It is not the system that suddenly changes. It is our description of the system. We choose a new wave-function because via the measurement process the system is different. The system change can be gradual or even delayed. When we interact with the measuring device our knowledge about the system changes in a classical way and we then use an updated wave-function to describe it.

Note also the intimate involvement of thermodynamics in the measurement process...(you amplify a signal and must dissipate heat into an entropy dump). Google the terms "thermodynamic" and "quantum measurement" to see what I mean. The system has changed by assumption and so its description changes by assumption and due to its interaction with a measurement device you can only describe it continuously by describing both it and the large scale variables of the measuring device which register its outcome, said variables now being highly correlated with the quantum variable of the system being measured.

The "many worlds" of Everett are "many worlds of possibility" not of reality...and what is more there are just as many of these prior to the measurement event as there are after it...they consist of the many possible configurations of the measuring device's heat dump prior to the act of measurement. You fundamentally can't describe the measuring device with a wave function due to its necessarily thermodynamic nature. It must be described at best by a density operator, classical probabilities and all. As such sequences of measurements are necessarily non-deterministic unless your are careful about which measurements you make. No mystery, no need to puzzle over EPR experiments except to carefully avoid counterfactual hypotheses.

 

[jambaugh]

Let me add something about the concept of superposition. Starting with a classical example, If I am traveling north-west I am in a superposition of traveling north and traveling west. This doesn't mean I am traveling in two directions, only that the description of the direction I am traveling does not fall along standard cardinal directions.

Likewise when a quantum system is "in superposition" it is only relative to some choice of observable in which case the system's mode is not an eigen-mode of that observable. But the system is in only one mode, not two at once. It is just that we are using some observable other than the one about which we have full knowledge.

It might be even better to understand it in terms of one observable being a superposition of another.

In the case say of an electron passing through a double slit. Our "cardinal" observable is position because we grew up thinking of electrons as classical point particles, and because that is the observable we use in our electron detectors. But the electron is in a single mode described by another observable rather less intuitive than position.

The "collapse" of the electron to a position eigen-mode is no weirder than if in my classical example I suddenly turned north and my superposition of directions suddenly "collapsed" into a single direction. A wave-function "collapse" is a turn not a catastrophe!

 

[Dmitry67]

I am trying to make my posts short as it is not mathematics and words 'space', 'time', 'probability' mean different things for different people. So,

The "many worlds" are many worlds of possibility. Its no different from standard classical probability.

If you see it that way then for you the world in not symmetric, because one branch (say, dead cat) is a 'real' one while another one was just a 'lost opportunity'. For me it is symmetric.

So your view looks like exactly like a Multi-World observed using a so called frog's view (a view of an observer, as Max Tegmark defines it). We are almost on the same page, you just deny or ignore the 'bird's view' so you analyze only one branch of reality.

If I had correctly explained it could you give a hint why you prefer an assymetric view?

 

[jambaugh]

I am trying to make my posts short as it is not mathematics and words 'space', 'time', 'probability' mean different things for different people. So,
If you see it that way then for you the world in not symmetric, because one branch (say, dead cat) is a 'real' one while another one was just a 'lost opportunity'. For me it is symmetric.

Actually no. My view is that both "worlds" are conceptual, symmetry restored. But we pick the conceptual world which fits our experience. Experience is singular and so there's nothing with which to define a symmetry.

(Actually there is, and that is the covariance group describing the relationship between different observers' experiences. But that again is all within a single actuality.)

So your view looks like exactly like a Multi-World observed using a so called frog's view (a view of an observer, as Max Tegmark defines it). We are almost on the same page, you just deny or ignore the 'bird's view' so you analyze only one branch of reality.

At the quantum level I deny "reality" all together. It is exactly the assumption of an objective reality with objective state which leads to all the problems conceptualizing QM.
You can still describe objects in the more general language of processes. You replace "reality=what is" with "actuality=what happens". When "what happens" fits an objective ontological model then we say we are considering phenomena at the classical level, as for example when we are talking about "the moon". But when we push the limits of observation this correspondence breaks down and we must stick to describing processes only.

The vertical polarization 'ket' of a photon is not a description of the photon but rather a description of the class of photon source devices. Dually the vertical polarization 'bra' corresponds to a class of photon "sinks" i.e. detectors. They are modes of production/registration for a physical process not states of a physical object.

The math tells us how to express say an oblique polarization mode in terms of a superposition of vertical and horizontal modes and it also tells us the probability of one mode detector registering what another mode source produces.

Phenomena not objects ... observations and measurements not states. This is what is operationally meaningful in the framework of the empirical epistemology of science.

 

[Dmitry67]

Actually no. My view is that both "worlds" are conceptual, symmetry restored. But we pick the conceptual world which fits our experience. Experience is singular and so there's nothing with which to define a symmetry.

(Actually there is, and that is the covariance group describing the relationship between different observers' experiences. But that again is all within a single reality.)

Interesting. Actually, it was my very first thought when I learned about the Quantum Decoherence.

But then I had decided that if our consciousness chooses somehow one particular path every time then there are 2 options:

1. consciousness of all other humans magically falls into the same path. So we are always 'all together' and there is only one history of the mankind.
2. assumption #1 is too artificial, hence, consicousness of other people who surround us fell into different branches of reality. Hence most of the humans who surround us are P-zombies ( http://en.wikipedia.org/wiki/Philosophical_zombie )

For that reason I decided that our conscious actually split every time (may be qualia http://en.wikipedia.org/wiki/Qualia is actually a feeling of being split? )

Regards

 

[jambaugh]

Interesting. Actually, it was my very first thought when I learned about the Quantum Decoherence.

But then I had decided that if our consciousness chooses somehow one particular path every time then there are 2 options:

1. consciousness of all other humans magically falls into the same path. So we are always 'all together' and there is only one history of the mankind.
2. assumption #1 is too artificial, hence, consicousness of other people who surround us fell into different branches of reality. Hence most of the humans who surround us are P-zombies ( http://en.wikipedia.org/wiki/Philosophical_zombie )

For that reason I decided that our conscious actually split every time (may be qualia http://en.wikipedia.org/wiki/Qualia is actually a feeling of being split? )

Regards

Consciousness has nothing to do with quantum decoherence. It only has to do with, as I said, our choice of mental world picture of the many worlds of possibility in our imagination which we choose as the one which fits our experience. The experience depends on "what happens out there" independent of consciousness. If an electron falls in the woods, it makes a photon whether we're there to see it or not. (The decay of an higher atomic energy mode being an example of decoherence once the photon has interacted with enough of the environment.)

It seems to me that you've read too many flaky "interpertations" of QM. Study the Copenhagen at least to the point of understanding it before you pick another based on non-issues.

Collapse of the wave-function does require a conscious mind but only because that wave-function is a construct of the mind and not "what is out there". We make a conscious choice to update our description based on the new input of data a la a record of the system's interaction with a measuring device. This device doesn't need to be something we constructed. It can be, say, the track a cosmic ray made in a piece of orbiting ice. Nature does what nature does. One singular natural world of actuality.

 

[Dmitry67]

It seems to me that you've read too many flaky "interpertations" of QM. Study the Copenhagen at least to the point of understanding it before you pick another based on non-issues

Sorry, once enlightened you can not go back to the nightmare of the Copenhagen interpretation :)

I don’t hope I can make you change your mind, I just don’t understand how you can live with such inconsistent theory.

You clam that “My view is that both "worlds" are conceptual, symmetry restored” . Then you say “But we pick the conceptual world which fits our experience. Experience is singular and so there's nothing with which to define a symmetry.”

In the first sentence you claim that it is symmetric, in the second – that our experience is not. So you must introduce some kind of symmetry-breaking mechanism. Otherwise you can not get an asymmetric state from a symmetric one!

Copenhagen is awful, but at least they have a name of that beast – R-process. In your interpretation I don’t see it at all.

Regarding the consciousness, I just explicitly named it. You can hide behind the words “we” or “experience” if you believe that the word “consciousness” it too much abused in QM philosophy, but in general it is the same.

Finally, you did not explain how “we” (multiple people with multiple experiences) “pick the conceptual world” consistently, so many people opening the box all experience the same state of cat inside.

 

[jambaugh]

Sorry, once enlightened you can not go back to the nightmare of the Copenhagen interpretation :)

I don’t hope I can make you change your mind, I just don’t understand how you can live with such inconsistent theory.

You clam that “My view is that both "worlds" are conceptual, symmetry restored” . Then you say “But we pick the conceptual world which fits our experience. Experience is singular and so there's nothing with which to define a symmetry.”

In the first sentence you claim that it is symmetric, in the second – that our experience is not. So you must introduce some kind of symmetry-breaking mechanism. Otherwise you can not get an asymmetric state from a symmetric one!

The conceptual states are symmetric=equally imaginary. Neither ceased to exist. Neither conforms exactly to the quantum actuality because both are classical constructs, i.e. object based ontological models. The model doesn't cause the outcome. We pick the model best conforming to actuality. But the mental reality-models are categorically different from the physical actuality. All of them are fictions...but like parables they are useful fictions. Just because we derive truths from Aesop's fables doesn't mean we actually believe that "the crow and the pitcher" or "the fox and the grapes" were historical events.

Copenhagen is awful, but at least they have a name of that beast – R-process. In your interpretation I don’t see it at all.

Copenhagen is beautifully consistent with the role of science...pay attention to what happens and don't introduce prejudices based on what you think of as "reality".

Regarding the consciousness, I just explicitly named it. You can hide behind the words “we” or “experience” if you believe that the word “consciousness” it too much abused in QM philosophy, but in general it is the same.

But you must read the first person pronouns in the appropriate context.

Science=Empirical Epistemology
Epistemology=How We come to know.
You can't separate the observer from the language because the language is operational=about what we do.

It is because 1) the physics student begins learning classical physics where the language, although operationally meaningful in the classical domain, is coached in non-operational terms namely objective states of reality... and 2) quantum theory broaching that domain wall requires us to now work in explicit operational terms "what we do" "what we see" that the student can fall into the trap of thinking the "we" are necessary for the physical processes to occur.

Now it is only that quantum theory is explicitly phenomenological in its description and we can't and shouldn't use language which assumes privileged knowledge. We only talk about "what we see and do" or at least "what we can see and can do in principle". It is very hard to step out of the old objective state mind-set. We can invent all sorts of bazaar rationalizations (a.k.a. interpretations) to allow us to preserve it. But to understand QM we must let that go.

Copenhagen in its essence simply says that we don't need any further interpretation beyond the "what we see and do" phenomenology. Probabilities are probabilities of what we will see happen not of states of reality. Mode vectors express modes of production of quantum processes and do not express states of reality of objects.

Finally, you did not explain how “we” (multiple people with multiple experiences) “pick the conceptual world” consistently, so many people opening the box all experience the same state of cat inside.

We experience a "meow" and so reject the model which fails to predict a "meow"
or
We experience a stiff lifeless cat and reject the model which predicts.

But we still remember both models and so both still exist. They existed (in our heads) long before the cat entered the box.

Now let me ask you to reconcile delayed choice experiments with Many-worlds. When does the world split? Similarly there is a time-reversed "delayed choice" call it "advanced choice" when does the world split then?

Finally if we cannot experience these many worlds how can we grant them other than imaginary status in the context of science. How is belief in these worlds other than a religion?

 

[WaveJumper]

The conceptual states are symmetric=equally imaginary. Neither ceased to exist. Neither conforms exactly to the quantum actuality because both are classical constructs, i.e. object based ontological models. The model doesn't cause the outcome. We pick the model best conforming to actuality. But the mental reality-models are categorically different from the physical actuality. All of them are fictions...but like parables they are useful fictions. Just because we derive truths from Aesop's fables doesn't mean we actually believe that "the crow and the pitcher" or "the fox and the grapes" were historical events.


Copenhagen is beautifully consistent with the role of science...pay attention to what happens and don't introduce prejudices based on what you think of as "reality".

But you must read the first person pronouns in the appropriate context.

Science=Empirical Epistemology
Epistemology=How We come to know.
You can't separate the observer from the language because the language is operational=about what we do.

It is because 1) the physics student begins learning classical physics where the language, although operationally meaningful in the classical domain, is coached in non-operational terms namely objective states of reality... and 2) quantum theory broaching that domain wall requires us to now work in explicit operational terms "what we do" "what we see" that the student can fall into the trap of thinking the "we" are necessary for the physical processes to occur.

Now it is only that quantum theory is explicitly phenomenological in its description and we can't and shouldn't use language which assumes privileged knowledge. We only talk about "what we see and do" or at least "what we can see and can do in principle". It is very hard to step out of the old objective state mind-set. We can invent all sorts of bazaar rationalizations (a.k.a. interpretations) to allow us to preserve it. But to understand QM we must let that go.

Copenhagen in its essence simply says that we don't need any further interpretation beyond the "what we see and do" phenomenology. Probabilities are probabilities of what we will see happen not of states of reality. Mode vectors express modes of production of quantum processes and do not express states of reality of objects.



We experience a "meow" and so reject the model which fails to predict a "meow"
or
We experience a stiff lifeless cat and reject the model which predicts.

But we still remember both models and so both still exist. They existed (in our heads) long before the cat entered the box.

Now let me ask you to reconcile delayed choice experiments with Many-worlds. When does the world split? Similarly there is a time-reversed "delayed choice" call it "advanced choice" when does the world split then?

Finally if we cannot experience these many worlds how can we grant them other than imaginary status in the context of science. How is belief in these worlds other than a religion?

Well said. I am also very interested how MWI would address the delayed choice experiment.

 

[Hurkyl]

Well said. I am also very interested how MWI would address the delayed choice experiment.

Fine. But it's going to look just like an ordianry analysis:


The joint system of the particle pair and measuring devices started off in the state:

(|01> + |10>) |unmeasured> |unmeasured>

The interaction that results in first measuring device producing a measurement along the 0-1 basis results in the state

(|01>|zero> + |10>|one> )|unmeasured>
Note the relative state of the first measuring device is the mixed state
50% |zero> 50% |one>

The interaction that results in second measuring device producing a measurement along the 0-1 basis results in the state

|01>|zero>|one> + |10>|one>|zero>
The relative state of the pair of measuring devices is now
50% |zero> |one>
50% |one> |zero>

So if we condition on the second measuring device reading |zero>, we see that the first measuring device is definitely |one>


Now, if the second measurement was in the |0> + |1> & |0> - |1> basis, the second interaction would result in
(|00>|zero> + |10>|one>)(|zero> + |one>)
+ (|01>|zero> + |11>|one>)(|zero> - |one>)
The relative state of the pair of measuring devices is now
25% |zero> |zero>
25% |zero> |one>
25% |one> |zero>
25% |one> |one>

So if we condition on the second measuring device readong |zero>, we see that the first measuring device is still in the pure mixed state of 50% |zero> and 50% |one>


Any experiment that involved aggregating the results of many individual experiments to detect if there was interference or not would find in the first case the outcome is a definite "yes there was interference". In the second case, the (relative state of the) result of the experiment would a mixed state with a very high probability of "no there was no interference" and a very small probability of "yes there was interference".

 

[Dmitry67]

1
Now let me ask you to reconcile delayed choice experiments with Many-worlds. When does the world split? Similarly there is a time-reversed "delayed choice" call it "advanced choice" when does the world split then?

2
Finally if we cannot experience these many worlds how can we grant them other than imaginary status in the context of science. How is belief in these worlds other than a religion?

In MWI the decoherence occurs when photon hits the reception device. MWI does not have any problem with the 'delay' because in it wavefunction never collapses. In MWI wavefunction has a real physical sense while the particle behaiviour is just a result of the decoherence.

(Note that if you observe an outcome of an experiment from very far away, for example, open a box, then you are not decoherenced until you see at least few photons from the box.
Contraqry to Copenhagen with it 'magical' collapse decoherence is a process explained purely using the QM... )

So photon goes thru both slits, hits whatever device, et voila...

If you chose what device will be detecting based on some truly random quantum generator, then you have 2 branches of reality, one with screen and another with 2 telescope.

Finally you get the following branches:

* Branch-Telescopes
*** Photon hit telescope A
*** Photon hit telescope B
* Branch screen
*** Position (X,Y)
*** ... etc etc

2 Max Tegmark answers you question in the following way:

The key point to remember is that parallel universes are not a theory, but a prediction of certain theories. For a theory to be falsifiable, we need not be able to observe and test all its predictions, merely at least one of them

Then he compares the predictions of QM without an explicit wavefunction collapse with how we deal with interiors of the block holes. We can not test directly if GR equations are correct inside the horizon, but as it works everywhere else, so we assume there too.

Another analogy he provides: Hubble spaces. We can not observe what is outside of our cosmological horizon, but we also assume that physical laws work there.

So if we ahve a solution of 2 non-interactive cats, how can we deny the existence of the second one just based on the fact that we can not observe it? Nature provides us a way how we can test the interference when there is no much irreversibility involved, so why should we assume that another branch magically 'dissapear'?

 

[jambaugh]

In MWI the decoherence occurs when photon hits the reception device. MWI does not have any problem with the 'delay' because in it wavefunction never collapses. In MWI wavefunction has a real physical sense while the particle behaiviour is just a result of the decoherence.

Fine, now take out Occam's razor and chop away all those MW's and you still have decoherence occurring when the photon interacts with the reception device. Don't work with wave-functions, work with the more general description of density operators which can describe both sharp and non-sharp modes. Decoherence then is just the entropy of the photon increasing (entanglement with environment).

Quantum mechanics does not predict many worlds! It predicts outcomes of experiments. Quantum mechanics plus the mistaken reification of the wave-function leads some to the delusion of MWI and others to the delusion of FTL and time-reversed propagating pilot waves.

(Note that if you observe an outcome of an experiment from very far away, for example, open a box, then you are not decoherenced until you see at least few photons from the box.
Contraqry to Copenhagen with it 'magical' collapse decoherence is a process explained purely using the QM... )

So photon goes thru both slits, hits whatever device, et voila...

If you chose what device will be detecting based on some truly random quantum generator, then you have 2 branches of reality, one with screen and another with 2 telescope.

Finally you get the following branches:

* Branch-Telescopes
*** Photon hit telescope A
*** Photon hit telescope B
* Branch screen
*** Position (X,Y)
*** ... etc etc

Fine but by the same arguments you get many-worlds with classical probabilities long before QM was ever invented...that is unless you insist on a deterministic clockwork universe. So the primary issue is determinism.

2 Max Tegmark answers you question in the following way:

Then he compares the predictions of QM without an explicit wavefunction collapse with how we deal with interiors of the block holes. We can not test directly if GR equations are correct inside the horizon, but as it works everywhere else, so we assume there too.

Another analogy he provides: Hubble spaces. We can not observe what is outside of our cosmological horizon, but we also assume that physical laws work there.

So if we ahve a solution of 2 non-interactive cats, how can we deny the existence of the second one just based on the fact that we can not observe it? Nature provides us a way how we can test the interference when there is no much irreversibility involved, so why should we assume that another branch magically 'dissapear'?

But I argue that his comparison is flawed. The specific flaw is that you cannot deny the existence of the black hole. Its existence is predicted by GR. Its existence is operationally meaningful, we could in principle fly to one and drop stuff into it. (And again QM, the physical theory does not predict MW. Many worlds has no operational meaning...you can't in the theory of QM fly to one and drop physical things into it and watch them disappear.) I can deny the existence of ALL the many worlds including the one that conforms to our experience. Only the experiences are "real" not the object based model we conceptualize to keep all our experiences organized.

In short "reality" is our filing system not the things being labeled.

With my "interpretation" the predictions of quantum theory still hold as they are --by the very definition of a physical theory-- predictions about experiential phenomena and not assertions about the state of reality between acts of observation. That "state of reality" is a ghost limb left over from the language of classical physics. Think of it as a vestigial instinct about how to use a prehensile tail which we via evolution no longer possesses or need.

And given that my "interpretation" is consistent with QM and my "interpretation" denies the existence of Many Worlds, MW's cannot then be "predicted" by QM. So put some Occam's razorblades on a weed-eater and start hacking aways at those MW's.

 

[Hurkyl]

Fine, now take out Occam's razor and chop away all those MW's and you still have decoherence occurring when the photon interacts with the reception device.

Occam's razor isn't a dynamical law. It can't make a physical system spontaneously jump from one state to another.

 

[jambaugh]

Let me also add w.r.t. your quote form Max Tegmark

The key point to remember is that parallel universes are not a theory, but a prediction of certain theories. For a theory to be falsifiable, we need not be able to observe and test all its predictions, merely at least one of them

That is positively wrong. A theory is falsifiable through its predictions and in no other way. The statement

we need not be able to observe and test all its predictions

would be correct if it said

we need not observe and test all its predictions

but we do need to be able to in principle test any of its predictions.

Just as, if I am willing to sacrifice the blood, sweat, and billions of dollars, I can build a super-duper collider to test predictions of the standard model, I can also sacrifice my future by jumping into a black hole to verify the extension of GR into the interior of the event horizon. It is operationally meaningful to talk about what an astronaut might see if he crosses the event horizon of a black hole. We can describe how to go about choosing either to do this or not do this. T

here is no way to enter a particular one of Everett's many worlds and so no way to verify its existence much less predictions about what happens in that world. In fact the whole scheme was invented to handle the fundamental inability to "be" in the specific "world" where a particular non-deterministic outcome of a quantum experiment occurs.

Again its about determinism and not reality. In a physical theory we must stick with an operational definition. QM predicts operational indeterminacy. Maybe it is wrong but that's the prediction. Trying to preserve fundamental determinacy is like any other form of religious fundamentalism. You can't make existence conform to your prejudices, only verify or falsify where the prejudice is operationally meaningful or create a "reality" independent of actuality and live in that dream world.

 

[Dmitry67]

That is positively wrong. A theory is falsifiable through its predictions and in no other way. The statement would be correct if it said but we do need to be able to in principle test any of its predictions.

Just as, if I am willing to sacrifice the blood, sweat, and billions of dollars, I can build a super-duper collider to test predictions of the standard model, I can also sacrifice my future by jumping into a black hole to verify the extension of GR into the interior of the event horizon. It is operationally meaningful to talk about what an astronaut might see if he crosses the event horizon of a black hole. We can describe how to go about choosing either to do this or not do this.

Yes, say there are 2 falsifiability principles: weak and strong.
Max is an adept of the weak principle while you insist on the strong principle

So we had finally reached the point why I had started this thread. Isn't it time to 'relax' the falsifiability?

Otherwise, you close the door for most of the superstring theories whith their branes, multiverse... you know, all that stuff...

I don't think we can reach TOE without making some sacrifices.

 

[Dmitry67]

P.S. I think there is more fundamental principle.

Mathematics started from the addition of the stones (natural numbers). The reversed operation, substraction, was not "closed", so people invented the negative numbers.

multiplication forced people to invent rational numbers, then irrational and transcendental numbers, then complex numbers.

In all cases we 'extend' or 'extrapolate' what we see here and what we can test to what we can't test.

You say, billion dollars, super puper colliders, what's about particles at Planks mass? You say that In principle you can build such collider, bigger then solar system? Does that claim have any physical sense?

Nobody plans to jump into a black hole. No articles are delayed until whe have the very first kamikaze astranaut. Instead, we extrapolate GR to what is inside the black hole. In the same way we did for the negative numbers. If it works outside - it works inside!

 

[jambaugh]

P.S. I think there is more fundamental principle.

Mathematics started from the addition of the stones (natural numbers). The reversed operation, substraction, was not "closed", so people invented the negative numbers.

multiplication forced people to invent rational numbers, then irrational and transcendental numbers, then complex numbers.

In all cases we 'extend' or 'extrapolate' what we see here and what we can test to what we can't test.

But this is mathematics. It is not extrapolation of what is or what happens but rather extension of constructs within our imagination. And we can likewise construct "number systems" which have non-associative addition or arbitrarily weird mathematical universes.

With regards to Mr. Tegmark's mathematical universe he is effectively returning to Platonism wile trying to incorporate a reified wave-function interp. of QM. We learned to move away from taking our mathematics too seriously back when distinct models of geometry sans the parallel postulate led us to understand that there were a whole multitude of geometries, each elegant and self consistent and thus we could not via pure deduction select one over the other as a description of nature. Math and science began diverging at that time. Math was understood to be "virtual" and knowledge about mathematical constructs must begin with undefined terms and axioms. Science contrawise developed as an epistemological discipline distinct from pure reason. As one cannot serve two masters the epistemology of empiricism prevails. Thus any assertions which cannot in principle be empirically falsified must either be, math, a model, or a religion.

You say, billion dollars, super puper colliders, what's about particles at Planks mass? You say that In principle you can build such collider, bigger then solar system? Does that claim have any physical sense?

Certainly. It would be a matter of engineering with known materials (as opposed to say building Larry Niven's ring world which required some super-metal). That and an immense amount of time and resources.

Nobody plans to jump into a black hole. No articles are delayed until whe have the very first kamikaze astranaut. Instead, we extrapolate GR to what is inside the black hole. In the same way we did for the negative numbers. If it works outside - it works inside!

Right. Speculative theories are valid as scientific theories provided they are operationally meaningful i.e. one can falsify their claims in principle. That means one can describe how any individual or group could with sufficient resources come to know the answer to the implicit question.

Without this restriction the door is open to the wackiest of "theories" and arguments e.g. "how much does God weigh?" and "How many angels can dance on the head of a pin". We've (or most of us) have moved beyond such speculation outside of science's empirical domain.

 

[Dmitry67]

Math and science began diverging at that time. Math was understood to be "virtual" and knowledge about mathematical constructs must begin with undefined terms and axioms. Science contrawise developed as an epistemological disciplinedistinct from pure reason.

So how do you imagine the axiomatisation of physics (one of the Hilberts problems)? Iagree with Max Tegrmark that it is pure mathematics. The TOE will look like as a number of equations (or may even only one equation).

Do you believe that physics can not be covered completely by the pure mathematics? That there are some specific 'physical' axioms?

But listen let say we have some TOE equations: M1, M2, MN. Now you say: there are additional physical axioms which are not covered by M1-Mn.

In that case there are 2 options: if we can express these axioms in the language of mathematics then we just add equations P1,P2... to our previous list, getting a pure mathematical system again!

An axiom is a 'pure physical' when... when it can not in principle be written in a form of a formula! It must be something really weird... like a turtle or an elephant... or something like about the consciousness...

Certainly. It would be a matter of engineering with known materials (as opposed to say building Larry Niven's ring world which required some super-metal). That and an immense amount of time and resources.

Then we had already relaxed in once. For the scientists of the 17,18,19 centuries falsiability was an immediate action item. You have doubts - go and do the damned experiment NOW. If you would say "you know, we can verify in principle that world outside out huble space is the same in principle we just need to wait few billion years to see the light of the more distant sources they would laugh!

Compare:
* I will send you a wire of 10'000USD
* In principle, I can send you a wire of 10'000USD

Do you feel the difference? :) 'In principle' has a NEGATIVE meaning: in principle we can do it but... What is a practicle meaning of saying 'in principle, I can jump into a black hole' or 'in principle, I can wait 10**18 years...'?

It is nothing more then a mantra: if you repeat it many times, you are starting to believe in it :)

Without this restriction the door is open to the wackiest of "theories" and arguments e.g. "how much does God weigh?" and "How many angels can dance on the head of a pin". We've (or most of us) have moved beyond such speculation outside of science's empirical domain.

So mutiple branes = "How many angels can dance on the head of a pin"? :)