QM Uncertainty: Uncovering Hidden Variables

[moving finger]

the only way out is to avoid "free will": namely not to allow you somehow to decide to make that other choice.

what exactly do you mean by "free will"?
How can I make a choice "other than" the choice that I did make?
MF

 

[vanesch]

a. I measure one of an entangled pair at an angle I choose at 3:30pm.
b. That causes it to have a definite spin orientation at the time of emission, 3:00pm. (However, note that there is still a random element present.)
[...]

This is indeed a possibility, but as I outlined somewhere, it simply means that experimental science has no meaning. Indeed, if what I'm going to measure in the future influences what is happening in the past, I cannot conclude much.

Imagine the following "experiment": I have 2 wires, and on a panel, there's a light bulb. I want to find out whether the light bulb is connected to the two wires, so I take a battery, and connect them to the light bulb: it lights up. I disconnect the battery: it goes out. I reconnect it: it goes on again.
Conclusion of my experiment: yes, these wires somehow are connected (or pilot) the lightbulb.

But maybe not at all ! Something else is making this lightbulb light up and go out, and this influences me, connecting exactly a few nanoseconds earlier, each time, the wires to the battery and not.

So I cannot even determine from my experiment that the wires have anything to do with the lightbulb ! You have to leave aside this possibility if you are going to consider the experimental scientific method at all, no ?

cheers,
Patrick.

 

[vanesch]

I don't follow you here. You're saying MWI rejects determinism? I thought the whole point of MWI was to get rid of the pesky collapse postulate, leaving only the deterministic evolution? Or maybe you're making the higher-level point that this doesn't really work and MWI needs to "smuggle in" some notion of probability.

Absolutely. I think "pure MWI" doesn't work for the probabilititic aspect, and something extra is needed.

But whatever you meant, I don't think it's the fundamental objection to MWI. MWI forces us to hold that we have been deluded about the outcomes of all the science experiments that have ever been done -- including the ones that led to QM in the first place. That is a very uncomfortable position for a theory to be in... totally unprecedented in the history of science (or, more broadly, rational thought).

No, we are not completely deluded, only partially

As I've been advocating a few times already here, you can have a view where there is indeed a quantum world out there evolving deterministically out there, respecting all symmetries (unitary evolution), and an observer, evolving through all those "branches", making LOCALLY each time his choice for the next branch upon his local "observations" (= entanglement with other stuff, and "choice" to be in one of those branches).

This last part is indeed an extra postulate, outside of strict MWI, (as said above), is probabilistic, and is local (to the observer). It also explains fully his measurement history. Now, you can think of it what you want, but it IS a working explanation. There's no delusion in it, not any more than the wave function in Bohm. It is the same wave function.

In Bohm, there is a *physical token* which obeys non-local laws, in my version, there is a "mental token" which obeys local laws...

cheers,
Patrick.

 

[moving finger]

This is indeed a possibility, but as I outlined somewhere, it simply means that experimental science has no meaning. Indeed, if what I'm going to measure in the future influences what is happening in the past, I cannot conclude much.

If the world is completely deterministic then it is just as correct to say the future influences the past as it is to say the past influences the future. In fact both past and future are fully determined.

It is possible that the universe operates this way.

Are you suggesting that experimental science would have no meaning in such a deterministic world?

I think not.

MF

 

[vanesch]

Are you suggesting that experimental science would have no meaning in such a deterministic world?

Yes, that's what I'm saying. In a fully deterministic world, indeed, experimental science doesn't make sense, because an essential ingredient in experimental science is the detection of a correlation of an effect with a free choice, which is assumed to have some "statistical independence" from the causal relationship under effect.
Let us look at the example of a new drug, that has to be tested. The idea is that somehow the mapping in which certain patients receive the drug, and others receive a placebo, or an old drug, is determined "independently". If however, this mapping is deterministically fixed, nothing can stop you from thinking that the order in which the patients come in is ALSO deterministically fixed, so that the patients with a serious disease happen to get the placebo, and those with lighter problems, the new drug. So the wrong conclusion will be that the new drug works very well. There is nothing "improbable" about it, because, by definition, in a deterministic view, probabilities don't make sense.

I see determinism as a structure in time, which resembles a structure in space, like, say, a pen. Let's say that the pen is lying along the z-axis, our "time" axis. And our "current time" is a slice at 2 cm from the back of the pen. Moving along the z-axis, we have a circular section of plastic and ink, which remains there for a while ; suddenly the radius of the circular section gets narrower, then we have a small metal disk which grows and then diminishes, and then there's nothing anymore. We can go back, and forward in z, we will have a "deterministic" section. You cannot conclude anything about these observations. Any "law" you could find based upon those observations is completely arbitrary.
You need to be able to assume "statistical independence" of your choices, and the mechanism under study ; and this "statistical independence" is impossible in a strictly deterministic universe, because all possible conspiracies are a possibility.

Of course, you could have a deterministic universe, in which everything behaves AS IF you had statistical independence between your choices and the process under study. But that, by itself, would be an enormous conspiracy !
A bit like the mice were guiding human science in the Hitchhiker's guide to the Galaxy :-)

cheers,
Patrick.

 

[DrChinese]

This is indeed a possibility, but as I outlined somewhere, it simply means that experimental science has no meaning. Indeed, if what I'm going to measure in the future influences what is happening in the past, I cannot conclude much.

Imagine the following "experiment": I have 2 wires, and on a panel, there's a light bulb. I want to find out whether the light bulb is connected to the two wires, so I take a battery, and connect them to the light bulb: it lights up. I disconnect the battery: it goes out. I reconnect it: it goes on again.
Conclusion of my experiment: yes, these wires somehow are connected (or pilot) the lightbulb.

But maybe not at all ! Something else is making this lightbulb light up and go out, and this influences me, connecting exactly a few nanoseconds earlier, each time, the wires to the battery and not.

So I cannot even determine from my experiment that the wires have anything to do with the lightbulb ! You have to leave aside this possibility if you are going to consider the experimental scientific method at all, no ?

cheers,
Patrick.

Sure, what you are saying makes sense, and yet that is exactly what needs re-thinking.

1. Our world is experimentally demonstrated as being full of both identifed causes and unidentified random effects. So your light bulb example applies only to that large subset that is what we refer to as deterministic. It is the other group that needs more explanation. You cannot deny that the future MIGHT have SOME role in explaining the random effects. Of course, I offer no convincing proof either. merely speculation.

2. There is nothing that says the future can't have a small role to play in what happens in the present. Two simple hypothetical examples: a) We are barely influenced by events occurring in Andromeda, but that does not mean there is no influence. Similarly, the influence from the future could be very mild. b) Look at how hard it is to create a singlet state! Such state allows us to see some strange quantum behavior (Nightlight calls it a parlor trick). And perhaps that is because the influence from our future is so subtle that it is difficult to otherwise see.

The way I see it, we are being asked to give up strict locality or strict causality if we reject hidden variables. Perhaps the least intrusive modifications we should make to theory will have us accept locality and acknowledge that the future could influence the past in a way which appears totally random from our perspective. Given symmetry considerations alone, I would think it is worth at least considering. And yet, in most respects, causality - and the scientific method! - would still apply.

 

[seratend]

Let us look at the example of a new drug, that has to be tested. The idea is that somehow the mapping in which certain patients receive the drug, and others receive a placebo, or an old drug, is determined "independently". If however, this mapping is deterministically fixed, nothing can stop you from thinking that the order in which the patients come in is ALSO deterministically fixed, so that the patients with a serious disease happen to get the placebo, and those with lighter problems, the new drug. So the wrong conclusion will be that the new drug works very well. There is nothing "improbable" about it, because, by definition, in a deterministic view, probabilities don't make sense.
Patrick.

Beware, you are just describing what is called an unlikely event or realisation: an event with probability= 0 but that may occur in an experimental trial (just a very rare event, like the "winning at the lottery" event).
There is not any incompatibility between the deterministic and probabilistic formulation of a problem. Only the hypotheses, may be incompatible (e.g. interpretation of "independent", probability law etc ...).
Therefore, when we verify the probability frequency in an experimental trial we must not forget that this trial may belong to an unprobable event set (i.e. we win at the lottery).

Seratend.

 

[moving finger]

Yes, that's what I'm saying. ... There is nothing "improbable" about it, because, by definition, in a deterministic view, probabilities don't make sense.

I disagree. Probability (in the mind of an agent) usually relates simply to the agent's epistemic abilities - ie it's knowledge of the process concerned and it's ability to predict an outcome. Therefore even if I know that a particular process is completely deterministic (such as the toss of a coin) I may still be unable to predict the outcome, hence must resort to probability. My epistemic horizon does not allow me to distinguish between (A) a truly random and ontically indeterministic coin-toss, and (B) an ontically deterministic but unpredictable coin-toss. As far as I am concerned, both are simply epistemically indeterminable.

MF

 

[vanesch]

I disagree. Probability (in the mind of an agent) usually relates simply to the agent's epistemic abilities - ie it's knowledge of the process concerned and it's ability to predict an outcome.

Yes, that's the Bayesian view, I presume. However, I would think - maybe I'm wrong - that you need at least a few statements concerning statistical independence in order to infere ANYTHING that way (the law of large numbers also assumes somehow "independent trials"). I would think that strict determinism doesn't allow you to say that any event is "statistically independent" of any other (it is this "independence" which I call somehow "free will", I'm realising this now myself).
To me, a deterministic universe is a "frozen structure in 4 D". This can then take on ANY form or shape. Anything can happen at ANY moment. There is no need for a kind of "stationarity in time evolution". No time evolution laws are needed in a deterministic universe. The structure just "is", just like a pen just "is" and there is no way to deduce the existence of the metal ball in the tip when you know about the cross section in the plastic and ink.
I'm not saying that there are deterministic universes which COULD also be "stationary and ergodic" so that statistics DOES work out there, but my only point was that there is no reason for it to be so.

cheers,
Patrick.

 

[moving finger]

Yes, that's the Bayesian view, I presume. However, I would think - maybe I'm wrong - that you need at least a few statements concerning statistical independence in order to infere ANYTHING that way (the law of large numbers also assumes somehow "independent trials"). I would think that strict determinism doesn't allow you to say that any event is "statistically independent" of any other

Determinism would force all events to be ontically dependent, yes. But not necessarily epistemically dependent (ie we might not be able to detect the dependence). For example, QM suggests that the quantum world is epistemically indeterminable (we cannot detect any dependence at the quantum level) but we cannot conclude from this that it is ontically indeterministic (ie determinsitic hidden variables theories are still valid).

(it is this "independence" which I call somehow "free will", I'm realising this now myself).

oooops. What is "free will"?

To me, a deterministic universe is a "frozen structure in 4 D". This can then take on ANY form or shape. Anything can happen at ANY moment. There is no need for a kind of "stationarity in time evolution". No time evolution laws are needed in a deterministic universe. The structure just "is", just like a pen just "is" and there is no way to deduce the existence of the metal ball in the tip when you know about the cross section in the plastic and ink.

I'm not sure what you are trying to say here. In the 4D block time model, each 3D-space cross-section represents a snapshot of space (like frames in a movie film). As time "progresses" we are just moving from one frame to another (so to speak).
I don't see where the problem is?

MF

 

[vanesch]

I'm not sure what you are trying to say here. In the 4D block time model, each 3D-space cross-section represents a snapshot of space (like frames in a movie film). As time "progresses" we are just moving from one frame to another (so to speak).

Well, this 4D block can then just take on ANY shape, there needs to be no "statistical regularity" in the evolution of this 3D slice. That's what I was trying to show with my ballpoint. There is no need for any evolution law that relates one 3D slice to the next one, and it is such an evolution law that gives the inhabitants of these 3D slices the impression that they can use epistemically a statistical description of this evolution. Of course it is a possibility, but this places high constraints on the 4D shapes that are possible.
Statistical analysis of the shape of the 2D slice of a pen doesn't mean much, so in the same way, statistical analysis of the shape of 3D slices of an arbitrary 4D shape shouldn't learn us much either, no ? You need peculiar 4D shapes for this to hold, which make "statistics work" from one 3D slice to another.

cheers,
Patrick.

 

[moving finger]

Well, this 4D block can then just take on ANY shape, there needs to be no "statistical regularity" in the evolution of this 3D slice.

No, I don't see this. The 4D block is fixed and static, and the inter-relation of the slices is fixed by determinism, I don't understand what you mean by "take on any shape"?

That's what I was trying to show with my ballpoint. There is no need for any evolution law that relates one 3D slice to the next one, and it is such an evolution law that gives the inhabitants of these 3D slices the impression that they can use epistemically a statistical description of this evolution.

But there is an evolution law which relates one 3D slice to the next - the deterministic laws of nature.

Of course it is a possibility, but this places high constraints on the 4D shapes that are possible.

I still don't know what you are trying to say. In a deterministic world, the configuration of the entire 4D block is fully determined by the laws of nature. One cannot get much more constrained than that.

Statistical analysis of the shape of the 2D slice of a pen doesn't mean much, so in the same way, statistical analysis of the shape of 3D slices of an arbitrary 4D shape shouldn't learn us much either, no ?

The 3D slices represent our "present". I think what you are looking for in wanting to probe the 4th dimension is to have foreknowledge? (to know the future as well?)
MF

 

[vanesch]

I still don't know what you are trying to say. In a deterministic world, the configuration of the entire 4D block is fully determined by the laws of nature. One cannot get much more constrained than that.

Well, these "laws of nature" could simply be a catalog of arbitrary 3D slices, no ? What is the "law of nature" describing the 2D slices of a ballpoint ?

I know what you mean: you mean that there are some differential equations that relate these 3D slices in a very simple way, "locally" and "in a reductionist way". But that's a VERY PECULIAR KIND of determinism ! This is a very peculiar "symmetry" rule that this 4-D shape has to satisfy. Because there could be a very complicated "law of nature" which somehow reads:
"look up the current 3D slice in the Big Catalog", turn the catalog 1 page further, and this is the prediction of the next 3D slice.
This is a "law of nature" with the right "big catalog", that always works.
It is impossible for us to know it, of course, but there could be such a "catalog" and that would then be the "law of nature", which deterministically joins each 3D slice to the next.
In the case of our ballpoint, the "big catalog" is simply its technical drawing in 3D, sliced up in 2D slices. That technical drawing can be as simple, or as complicated, as the designer of the ballpoint decided.
So given this pathetic example of "law of nature" which determines the next 3D slice from the former, you see that ANY shape in 4D is possible. There is of course only ONE such shape, THE shape of the deterministic universe, but a priori, there's no reason why there should be SIMPLE laws of nature linking the different 3D slices, no ?

cheers,
Patrick.

 

[moving finger]

Well, these "laws of nature" could simply be a catalog of arbitrary 3D slices, no ? What is the "law of nature" describing the 2D slices of a ballpoint ?

The laws of nature are found in the correlations between the slices.
If the slices are indeed arbitrary as you suggest, with no correlation between them, then this suggests absence of law.

In the ballpoint case, the "law of nature" of the ballpoint tells you how one slice changes to another slice as you move along the length of the ballpoint. If the ballpoint slices are arbitrarily random then this would imply no law (or randomness), but if there is correlation between the slices (as indeed there is in the case of a ballpoint) then the law of nature of the ballpoint tells you how these slices correlate with each other.

I know what you mean: you mean that there are some differential equations that relate these 3D slices in a very simple way, "locally" and "in a reductionist way".

No, I mean the slices are correlated with each other, they are not simply arbitrary.

But that's a VERY PECULIAR KIND of determinism !

What I have described is exactly deterministic. If the slices were arbitrary then one could claim this would lead an observer in this world to conclude that the world is indeterministic (the slices are not crrelated, there is no law), but if the slices are correlated then the determinsitic laws which decribe the correlations are the laws of nature.

This is a very peculiar "symmetry" rule that this 4-D shape has to satisfy. Because there could be a very complicated "law of nature" which somehow reads:
"look up the current 3D slice in the Big Catalog", turn the catalog 1 page further, and this is the prediction of the next 3D slice.

Yep, this would work. This would be a (very large, infinite?) look-up table of the slices.

This is a "law of nature" with the right "big catalog", that always works.
It is impossible for us to know it, of course, but there could be such a "catalog" and that would then be the "law of nature", which deterministically joins each 3D slice to the next.

In a determinsitic world we observe the laws of nature to be apparently fixed with time (the law of gravity for example seems to be invariant). This means that we do not need to have a big catalog which contains a unique description of every slice - instead we can reduce the whole problem down to having just one page (description of one slice) plus a one-time description of the laws of nature which allows us (in principle) to calculate all of the other slices.

In the case of our ballpoint, the "big catalog" is simply its technical drawing in 3D, sliced up in 2D slices. That technical drawing can be as simple, or as complicated, as the designer of the ballpoint decided.

Yes, again this is the look-up table version. But if the slices are correlated we can actually reduce the information, so that rather than having an infinite number of cross-sectional drawings, we have instead a small number of key cross-sections plus a series of equations (the "laws of the ballpoint") which tell us how the other (undrawn) cross sections are correlated with the drawn ones. In the ballpoint case, we may only be able to do this by postulating that the laws suddenly "change" are some points (ie there are discontinuities and the laws of the ballpoint are not in fact fixed) - but nevertheless we can still describe the ballpoint using a limited series of cross-sections plus a limited number of laws, rather than an infinite number of slices.

So given this pathetic example of "law of nature" which determines the next 3D slice from the former, you see that ANY shape in 4D is possible.

Any shape in 4D is possible in principle. But in a deterministic world with fixed laws, then specifying just one slice allows us to construct the entire world.

There is of course only ONE such shape, THE shape of the deterministic universe, but a priori, there's no reason why there should be SIMPLE laws of nature linking the different 3D slices, no ?

There is a reason, I believe - and that reason (IMHO) is that the emergence of life would have been extremely unlikely in a world with variable laws (ie if the laws of nature were random or not fixed) - in fact we DO see that the laws of nature appear to be fixed - hence we may live in a deterministic universe.

Note : even if the laws are not fixed, if they vary in a deterministic way then this variation becomes just another "law", and determinism is still possible.

MF

 

[vanesch]

If the ballpoint slices are arbitrarily random then this would imply no law (or randomness), but if there is correlation between the slices (as indeed there is in the case of a ballpoint) then the law of nature of the ballpoint tells you how these slices correlate with each other.

Until you reach the tip ! But there IS a "law": the ballpoint's designer's 3D drawing.

No, I mean the slices are correlated with each other, they are not simply arbitrary.

Well, they are correlated in the "Big Catalog" too, of course: they are on neighboring pages. But of course I know what you mean: you mean that you can isolate SMALL PARTS of the slices, and then find systematic, "simple" laws that apply to ALL these small parts. But THAT is exactly the kind of "statistical independence" I was talking about in the beginning, which is necessary for experimental science to even make sense. It was my impression that this "statistical independence" of small parts of the slices is somehow not something natural for a deterministic view, while it appears almost naturally in a probabilistic universe (where the "rigid 4D structure" doesn't make sense, and where we are from the beginning "slice - oriented").

What I have described is exactly deterministic. If the slices were arbitrary then one could claim this would lead an observer in this world to conclude that the world is indeterministic (the slices are not crrelated, there is no law), but if the slices are correlated then the determinsitic laws which decribe the correlations are the laws of nature.

They are not "arbitrary" in the sense of "completely statistically independent", they are arbitrary in exactly the same sense in which the shape of a ballpoint is "arbitrary", but functional. Not just "any shape of plastic, ink and steel" will give you a usefull ballpoint. But you cannot formulate a simple law that relates each 2D slice of the ballpoint to its next.
This is how I see a priori a "deterministic" universe. A (maybe useful) shape in 4D.

In a determinsitic world we observe the laws of nature to be apparently fixed with time (the law of gravity for example seems to be invariant). This means that we do not need to have a big catalog which contains a unique description of every slice - instead we can reduce the whole problem down to having just one page (description of one slice) plus a one-time description of the laws of nature which allows us (in principle) to calculate all of the other slices.

And moreover, these laws (as compared to the catalog) are EXTREMELY SIMPLE. This is what is so amazing, in a deterministic setting, no ?

Yes, again this is the look-up table version. But if the slices are correlated we can actually reduce the information, so that rather than having an infinite number of cross-sectional drawings, we have instead a small number of key cross-sections plus a series of equations (the "laws of the ballpoint") which tell us how the other (undrawn) cross sections are correlated with the drawn ones. In the ballpoint case, we may only be able to do this by postulating that the laws suddenly "change" are some points (ie there are discontinuities and the laws of the ballpoint are not in fact fixed) - but nevertheless we can still describe the ballpoint using a limited series of cross-sections plus a limited number of laws, rather than an infinite number of slices.

Ah, I see what you mean: any kind of "functionality" requires some regularity, which expresses itself as a simplification of the "catalog law of nature".

Any shape in 4D is possible in principle. But in a deterministic world with fixed laws, then specifying just one slice allows us to construct the entire world.

Yes, but even in the "catalog world", one slice allows us to construct the entire world: just read the catalog :-)
What is amazing is the simplicity, and a simplicity in such a way that statistics works. I have the impression that an "a priori probabilisitic world" would be inclined more naturally to such simple laws than a deterministic 4D shape.

There is a reason, I believe - and that reason (IMHO) is that the emergence of life would have been extremely unlikely in a world with variable laws (ie if the laws of nature were random or not fixed) - in fact we DO see that the laws of nature appear to be fixed - hence we may live in a deterministic universe.

Hehe, but that argument is probabilistic :-))

Note : even if the laws are not fixed, if they vary in a deterministic way then this variation becomes just another "law", and determinism is still possible.

EXACTLY ! And if you pull this through to the most general case, where the deterministic laws are varying with position and time, you're back to the "catalog". This, to me, is the "generic" deterministic universe.


cheers,
Patrick.

 

[Kirk Gregory Czuhai]

and then a guy like me comes along! can you determine whether i will post again after this post? most likely? and you will say that my post will probaby be determined to not make any sense! but will it be determined to be based on this one post?
love and peace,
and,
peace and love,
(kirk) kirk gregory czuhai
owner/ceo Heaven Sense
http://HeavenSense.WS
http://Allendale.WS
http://Czuhai.WS
http://LittleHoney.WS
p.s. i am convinced we live in a COMPLEX universe, which is neither completely
predictable (deterministic) nor completely random (indeterministic) so therefore
everyone is partly right and partly wrong; right or wrong?

 

[moving finger]

and then a guy like me comes along! can you determine whether i will post again after this post? most likely? and you will say that my post will probaby be determined to not make any sense! but will it be determined to be based on this one post?

I think you will find that no agent operating WITHIN a deterministic world can make infallible preictions ABOUT that deterministic world.

(thus : it matters not whether the world is deterministic or not, one cannot make infallible predictions from within that world)

MF