Undergrad CFD - Counterfactual Definiteness

[RUTA]

Can we, at least, agree on this much?

If one says there is no violation of 'causal locality', then one is forced to say that the PAIR of spacetime events – i.e. the IMPLEMENTATION of Bob's setting and the REGISTRATION of Alice's outcome – is 'nonseparably connected'.

Again, without specifying a particular QM interpretation, I would say the two outcomes are nonseparable if they are locally causal.

 

[Eye_in_the_Sky]

Again, without specifying a particular QM interpretation, I would say the two outcomes are nonseparable if they are locally causal.

Okay. I will recast my claim as follows:

A joint-measurement of an (appropriately prepared) entangled property is performed in spacetime regions A and B at spacelike separation.

If one says there is no violation of 'causal locality', then one is forced to say:

The 'state of affairs' in spacetime region A and the 'state of affairs' in spacetime region B are together in a condition of 'nonseparability'.

 

[RUTA]

Okay. I will recast my claim as follows:

A joint-measurement of an (appropriately prepared) entangled property is performed in spacetime regions A and B at spacelike separation.

If one says there is no violation of 'causal locality', then one is forced to say:

The 'state of affairs' in spacetime region A and the 'state of affairs' in spacetime region B are together in a condition of 'nonseparability'.

If by "state of affairs" you're referring to the device settings and experimental outcomes, then yes.

 

[Simon Phoenix]

In Relativity simultaneity is only convention

How so?

Let's imagine the classic train scenario. Alice is placed in the centre of a train carriage. Unfortunately for our hapless heroine, some dastardly criminal has strapped an explosive device to her. There is a light source at each end of the carriage. If the light from these sources reaches her at the same time as judged by the photodetectors on the explosive device - then it's goodbye Alice.

Bob, sitting on the embankment, watches the train go past and sees flashes from the end of the carriage that are simultaneous (by his reckoning) just as Alice passes him.

So does our heroine survive, or is she blown to bits?

I suspect Alice and Bob are going to view 'simultaneity' as something a little more serious than merely 'convention'

So it's outside of domain of applicability for Relativity

Again, how so?

The measurements of Alice and Bob are merely 2 events in spacetime. It doesn't matter one jot whether these events are measurements on entangled particles or measurements of the colour of the eyes on two fluffy bunnies. The events don't even have to be measurements of any kind - just two points in spacetime where something could happen, in fact.

What you seem to be saying is that relativity is not applicable for all possible events at these spacetime locations.

If there is a spacelike interval separating these two events, then it is possible that there are different orderings for the events in different frames.

So how can we say which event 'influences' the other when we talk of entanglement?

 

[zonde]

If the light from these sources reaches her at the same time as judged by the photodetectors on the explosive device - then it's goodbye Alice.

Bob, sitting on the embankment, watches the train go past and sees flashes from the end of the carriage that are simultaneous (by his reckoning) just as Alice passes him.

So does our heroine survive, or is she blown to bits?

I suspect Alice and Bob are going to view 'simultaneity' as something a little more serious than merely 'convention'

We can use word "simultaneously" in two different ways. We can describe single spacetime event (light pulses arrive at the same time at some place) or we can describe two distant spacetime events (light pulses are emitted at the same time from separate sources). If we describe single spacetime event then of course it's physical fact and has nothing to do with any convention.

Again, how so?

The measurements of Alice and Bob are merely 2 events in spacetime. It doesn't matter one jot whether these events are measurements on entangled particles or measurements of the colour of the eyes on two fluffy bunnies. The events don't even have to be measurements of any kind - just two points in spacetime where something could happen, in fact.

What you seem to be saying is that relativity is not applicable for all possible events at these spacetime locations.

Points in spacetime diagram by themselves represent physical facts and it has little to do with what I'm saying.

If there is a spacelike interval separating these two events, then it is possible that there are different orderings for the events in different frames.

Inconsistent orderings of spacetime events in different reference frames is a feature of relativity. It's fine (and very convenient) as long as there is no FTL phenomena.

 

[Simon Phoenix]

We can use word "simultaneously" in two different ways

We can use the word "simultaneously" however we like, but there is only one meaning in physics really. Two events are said to be simultaneous in a given inertial reference frame if they have the same time coordinate in that frame.

Simultaneity is relative, if this is what you mean by a matter of 'convention' then I agree. I would not personally describe it as a 'convention' though.

Some authors have even suggested that in fact one could even go so far as to suggest that all of special relativity is really a study of the relativity of simultaneity - not sure I'd fully agree with that statement, but I can see where they're coming from, so to speak.

Inconsistent orderings of spacetime events in different reference frames is a feature of relativity. It's fine (and very convenient) as long as there is no FTL phenomena.

So let me try to understand what you're saying.

Experiment 1 : our Alice and Bob make spacelike separated measurements on two particles. These particles are just prepared in random states with no correlation or entanglement whatsoever

Experiment 2 : same as above but now with entangled particles

Are you suggesting, somehow, that special relativity is applicable in the first experiment (so we're entitled to say that the order of measurement can differ in differing frames), but not in the second because we're now making measurements of entangled particles?

Or are you suggesting that entanglement (and maybe the Bohm view of things) invalidates special relativity?

 

[zonde]

So let me try to understand what you're saying.

Experiment 1 : our Alice and Bob make spacelike separated measurements on two particles. These particles are just prepared in random states with no correlation or entanglement whatsoever

Experiment 2 : same as above but now with entangled particles

Are you suggesting, somehow, that special relativity is applicable in the first experiment (so we're entitled to say that the order of measurement can differ in differing frames), but not in the second because we're now making measurements of entangled particles?

You might say so. Basically relativity is applicable in both cases as long as we describe our observations phenomenologically and do not speculate about possible physical models behind entanglement.

Or are you suggesting that entanglement (and maybe the Bohm view of things) invalidates special relativity?

Sort of yes, but I would rather say that entanglement phenomena (violation of Bell inequalities) indicates that domain of applicability of relativity is limited.

 

[Eye_in_the_Sky]

Suppose Bob has setting b1, and Alice gets a series of outcomes S. Now suppose that if Bob had had setting b2, Alice would have got the same series of outcomes S. Then, since the correlation has changed (due to the changed settings of Bob), and Alice's outcomes are the same, Bob's outcomes must have changed. And this goes vice versa for Alice. So, this would mean that Alice's outcomes would only depend on her settings, and similarly for Bob. But then there would be no correlation dependent on the relative (!) parameters (it would be local). So, I suppose then that Bob's setting does influence the outcomes of Alice (and vice-versa). It just happens in a way that it is not noticed (locally)!

Hi, entropy1. Thanks for contributing to this thread.

There is a difficulty with the above argument. The argument, as it stands, would apply equally well to a 'classical' correlation experiment. ... But, even there, there can be "correlation dependence" on the "relative parameters".

So, how can we clarify the matter? One way, is to do a step-by-step deconstruction of the full Bell argument in this context. Another way, is to choose a different entanglement scenario altogether, a much SIMPLER one, and pose our queries upon that background instead.

"Ah," you might ask, "there is a SIMPLER entanglement scenario I can consider?"

The answer is YES. And thus, I have started a new thread entitled:

"Bell made Simple - HARDY".

 

[Eye_in_the_Sky]

If one says there is no violation of 'causal locality', then one is forced to say:

The 'state of affairs' in spacetime region A and the 'state of affairs' in spacetime region B are together in a condition of 'nonseparability'.

If by "state of affairs" you're referring to the device settings and experimental outcomes, then yes.

Absolutely, the 'state of affairs' would include those.
________

You keep talking about the measuring devices as if they're in a quantum (unobserved) state. In that case, you need an interpretation of QM to answer questions about their status in spacetime.

Consider an inertial frame of reference in which the pair of outcomes occurs simultaneously, and let t_o be the time of occurrence in that frame.

Suppose there is no violation of 'causal locality', and suppose further that the joint-state of their instruments is 'separable' both before and after t_o.

But at t_o:

Each one's outcome is 'nonseparable' from the setting of the other; therefore, the joint-state of their instruments is 'nonseparable'.

... Is that wrong to say?

 

[RUTA]

Absolutely, the 'state of affairs' would include those.
________

Consider an inertial frame of reference in which the pair of outcomes occurs simultaneously, and let t_o be the time of occurrence in that frame.

Suppose there is no violation of 'causal locality', and suppose further that the joint-state of their instruments is 'separable' both before and after t_o.

But at t_o:

Each one's outcome is 'nonseparable' from the setting of the other; therefore, the joint-state of their instruments is 'nonseparable'.

... Is that wrong to say?

Now you're talking about the "state of the instruments," being "nonseparable" so I assume you're talking about the instruments in terms of being in a quantum state. I don't know what else you mean. If so, you need an interpretation of QM to discuss the situation ontologically because you have to deal with the measurement problem.

 

[Eye_in_the_Sky]

Now you're talking about the "state of the instruments," being "nonseparable" so I assume you're talking about the instruments in terms of being in a quantum state. I don't know what else you mean. If so, you need an interpretation of QM to discuss the situation ontologically because you have to deal with the measurement problem.

I may be having a conceptual difficulty.

To my understanding, the following conjunction is not logically possible:

each one's outcome is 'nonseparable' from the setting of the other

AND

the joint-state of their instruments is 'separable' .

Is that logically possible? ... for both statements to hold?

 

[bhobba]

each one's outcome is 'nonseparable' from the setting of the other
the joint-state of their instruments is 'separable' .

You are making it all way harder than it really is.

All Bell is saying is if you want the outcomes of measurements to be independent of the measurement then you need FTL.

The following CAREFULLY explains the issues and terms:
http://www.johnboccio.com/research/quantum/notes/paper.pdf

Thanks
Bill

 

[Simon Phoenix]

Each one's outcome is 'nonseparable' from the setting of the other; therefore, the joint-state of their instruments is 'nonseparable'.

Eye,

I've no idea where you're going with all of this and I think you're making things more complicated than they need to be.

Let's backpedal a bit and think about what the Bell analysis is all about. Let's pretend that QM hasn't been invented yet. We know nothing about 'separable' or 'non-separable' or 'wavefunctions'.

Now we have some experiment consisting of 2 pieces of measuring kit and some source. So in the usual fashion we arrange them like so
A <---------- S ----------> B
We can adjust the dial on the kit to measure at settings a,b, or c.
The outcome is just a single binary value 1 or 0 (a ping or a ding)

Everything is at 'black box' level. The only data we can record at each measuring station, for each timeslot, is the setting (a,b, or c) and the binary value obtained.

Our job is to see whether any correlations that might be observed can be explained at this very general level in terms of probability distributions that can actually be measured in this experiment.

So we quite naturally make the assumption that whatever the source is doing or generating (fields, particles, little green tribbles, etc) there are going to be some variables that will explain any correlation. We might not have any control of or access to these variables, but we assume they are underlying things and giving rise to the correlation. Furthermore we quite naturally assume that these variables are such that they have some existence independent of the measurement.

Now, it would be strange if A and B were miles apart and the results (the ping or ding) recorded at A depended in some way on the position of the dial (a,b or c) that had been chosen at B.

Let's call these kinds of variables 'classical-like' - they have properties that are very natural and reasonable. They exist outside of measurement, for one, and they don't bugger up relativity.

Now we write down the various conditional probabilities we have, do some manipulations, and find that there's a constraint on certain functions that can actually be measured in this experiment. So we know that ANY theory that utilises these kinds of variables must give predictions within these constraints.

We do the experiment and find that the results we get don't satisfy this constraint. So whatever is happening (fields, particles or tribbles) it cannot be described by a theory of this kind using these kinds of classical-like variables.

As soon as you want to try to describe things in terms of variables that have some existence independent of measurement (like everyday classical variables such as position or momentum or field strength and so on) then if you want to explain the observed results those variables have to have some non-local connection - crudely put, there must be some mechanism that transfers 'information' about settings at A to the system (kit plus tribble) at B in a way that buggers up relativity. You can't actually communicate FTL, in the sense that A and B can't use this to exchange information, but quite clearly real information about whether A has chosen a,b or c must be, in some sense 'accessible' to the kit plus tribble at B if we want to have our variables have some meaning independent of experiment.

So when you talk of the kit being 'non-separable' are you trying to understand things in terms of variables that have some objective existence outside of measurement and using 'non-separable' to describe this necessary 'information transfer mechanism'? Or do you mean something more akin to the non-separability described by QM?

 

[Simon Phoenix]

Each one's outcome is 'nonseparable' from the setting of the other; therefore, the joint-state of their instruments is 'nonseparable'.

Let's look at this from the QM perspective,

We'll model the experimental kit, the measuring devices, as quantum objects. The initial state of the correlated particles plus measuring devices is then given by

[ |10> + |01> ] ⊗ |A_initial> |B_initial>

where I'm ignoring normalization. So the particles are entangled, but the measuring devices are uncorrelated (and separable). They're not correlated to one another and nor are they correlated with the particles we're going to measure.

After the particles have interacted with the devices, but before the measurement is performed, the state evolves to

|10> |A₁>|B₀> + |01> |A₀>|B₁>

So the state of the particles plus measuring devices is entangled (or non-separable in the QM sense).

The state of the measuring devices alone is given by the density operator (non-normalized)

ρ = |A₁, B₀><A₁, B₀| + |A₀, B₁><A₀, B₁|

which is a correlated but not entangled state

So once the particles have interacted with the devices (but before the measurement) we can't 'separate' the particles plus devices.

You're trying to draw some conclusions about the measuring devices alone, in terms of non-separability, but that's not going to work within the QM picture of things.

I'm just repeating what RUTA has been trying to tell you using the QM formalism.

 

[RUTA]

I may be having a conceptual difficulty.

To my understanding, the following conjunction is not logically possible:

each one's outcome is 'nonseparable' from the setting of the other

AND

the joint-state of their instruments is 'separable' .

Is that logically possible? ... for both statements to hold?

Yes, the instruments are classical but the outcomes they register are described by a quantum state that depends on the settings of those instruments in nonseparable (assuming causal locality) fashion.

 

[Eye_in_the_Sky]

Yes, the instruments are classical but the outcomes they register are described by a quantum state that depends on the settings of those instruments in nonseparable (assuming causal locality) fashion.

Okay, RUTA ... I will go with that too. Thus, I am placed into a 'corner' with one last claim to make.
____

Suppose there is no violation of 'causal locality'. Then:

If we say that the states of their instruments bear a relation of 'separability' throughout the spacetime regions A and B, then we are forced to say

The 'quantum state' is PHYSICAL.

... Can we agree on that?

 

[RUTA]

Okay, RUTA ... I will go with that too. Thus, I am placed into a 'corner' with one last claim to make.
____

Suppose there is no violation of 'causal locality'. Then:

If we say that the states of their instruments bear a relation of 'separability' throughout the spacetime regions A and B, then we are forced to say

The 'quantum state' is PHYSICAL.

... Can we agree on that?

That depends on your interpretation of QM. You're certainly not forced to say that.

 

[morrobay]

I may be having a conceptual difficulty.

To my understanding, the following conjunction is not logically possible:

each one's outcome is 'nonseparable' from the setting of the other

Just regarding above and restate from previous.
Case 1: With non parallel settings a & b calculate QM predictions for spin 1/2 particles, P++ = P -- = 1/2 ( sin θ/2 ) ²
θ = a-b. Then do experiment
Case 2: Change setting at A, a >> a' and calculate predictions for P++ and P-- with θ = a'-b and do experiment.
If QM prediction in case 2 match results for case 2 then outcome at Bb
was not influenced and separable from setting change at A, a >> a'
If predictions in case 2 do not match results for settings in case 2 then there is a question:
" An influence on the very conditions which define the possible types of predictions regarding the future behavior of the system "
Ie: Outcome at B was influenced and non separable from setting change at A, a>>a'
The other option is giving up CFD. Then a superluminal influence does not apply in explaining result

 

[bhobba]

The 'quantum state' is PHYSICAL.

That is VERY interpretation dependent.

Here, for example, is the view of the Baysians:
https://www.quantamagazine.org/20150604-quantum-bayesianism-qbism/

QM is a morass of things that are difficult or impossible to pin down exactly.

Thanks
Bill

 

[Eye_in_the_Sky]

That depends on your interpretation of QM. You're certainly not forced to say that.

That is VERY interpretation dependent.

Ok ... Ok. I will have to recast my claim.

 

[Eye_in_the_Sky]

I've no idea where you're going with all of this ...

I was trying to resolve the dispute below:

Bhobba contends that the quantum correlations are compatible with both of these conditions taken together:

1) The joint state of Alice's measuring instrument and Bob's measuring instrument, in spacetime, is separable.

2) Their measuring instruments are mutually non-influencing.

I am saying that (at least) one of these conditions needs to be relinquished.

The dispute has now been resolved to my satisfaction. Bhobba is correct.

My contention was based upon a misconception. I was not properly distinguishing between these two distinct notions:

(i) The joint-state of X and Y is 'nonseparable'.

(ii) The 'separable' states of X and Y are 'nonseparably' connected.
__________

I will write (ii) as (2) and particularize X and Y to the instruments of Alice and Bob. I will also put that statement up for comparison with a similar looking statement that I will designate as (1):

(1) The 'separable' states of their instruments are 'causally' connected.

(2) The 'separable' states of their instruments are 'nonseparably' connected.

I'm not at all sure that the violation of the mathematical inequality has anything to do with locality (or non-locality) in QM.

First off, I think it's important to be clear about what is meant by 'locality' because this has different meanings in different contexts. What I mean by 'locality' in the context of the Bell inequality, and in an intuitive sense, is the following : the results of experiments 'here' are not affected by the settings of devices 'there'. [Or if they are, any such influence cannot travel faster than the speed of light]

Permit me to paraphrase your statement of LOCALITY as:

Bob's setting does not AFFECT Alice's outcome.

There is a problem with this statement. The word "affect" pertains to matters of 'causality'. But statement (2) above is talking about an 'acausal' connection. To say that Bob's setting is 'nonseparably' connected to Alice's outcome means that the setting and the outcome DO NOT even STAND in a 'cause' and 'effect' RELATIONSHIP; and if that is so, then it is TRUE BY DEFINITION that Bob's setting DOES NOT AFFECT Alice's outcome.

The diction is faulty.

Here is the set of definitions I am using for 'causality':

effect: a 'state of affairs' that is brought about by a 'cause'

affect: to act, in a manner of 'causation', so as to produce an 'effect'

influence: the agency through which an 'effect' is established

causation: the relationship between 'cause' and 'effect'

causality: the notion of 'causation'

Thus, to repeat, as you can see, (by definition) an 'effect' can NEVER HAPPEN if the RELATIONSHIP is ACAUSAL.

This fault in diction, however, is simple to correct – just rewrite the above statement of LOCALITY as:

Bob's setting is IRRELEVANT to Alice's outcome.

How, then, in this context is IRRELEVANT to be understood?

It means (roughly) this:

The 'physics in play' at Alice's station can be ASSUMED to be the same regardless of what Bob's setting happens to be.

This idea requires explanation.

 

[Eye_in_the_Sky]

As soon as you want to try to describe things in terms of variables that have some existence independent of measurement (like everyday classical variables such as position or momentum or field strength and so on) then if you want to explain the observed results those variables have to have some non-local connection - crudely put, there must be some mechanism that transfers 'information' about settings at A to the system (kit plus tribble) at B in a way that buggers up relativity. You can't actually communicate FTL, in the sense that A and B can't use this to exchange information, but quite clearly real information about whether A has chosen a,b or c must be, in some sense 'accessible' to the kit plus tribble at B if we want to have our variables have some meaning independent of experiment.

So when you talk of the kit being 'non-separable' are you trying to understand things in terms of variables that have some objective existence outside of measurement and using 'non-separable' to describe this necessary 'information transfer mechanism'? Or do you mean something more akin to the non-separability described by QM?

Hi, Simon. Right now, this is the very best I can do to explain myself.
______

In each run of the experiment:

At least one of the instruments must 'know' both the setting and the outcome of the other instrument.

Otherwise, the quantum correlations cannot happen.

But, how did that 'information' get there?

If we say that the 'information' got there via a 'causal' connection (i.e. through the agency of an 'influence'), then we are forced to say it is FTL.

On the other hand,

If we say that the 'information' quite simply is there in virtue of a 'nonseparable' connection (i.e. with no 'agent' acting within spacetime to bring over the 'information')

... then are we still not forced, nonetheless, to say that the connection is NONLOCAL?

I think so. I think everybody else should think so.

Simon, what do you think? ... What about everybody else?

 

[RUTA]

Hi, Simon. Right now, this is the very best I can do to explain myself.
______

In each run of the experiment:

At least one of the instruments must 'know' both the setting and the outcome of the other instrument.

Otherwise, the quantum correlations cannot happen.

But, how did that 'information' get there?

If we say that the 'information' got there via a 'causal' connection (i.e. through the agency of an 'influence'), then we are forced to say it is FLT.

On the other hand,

If we say that the 'information' quite simply is there in virtue of a 'nonseparable' connection (i.e. with no 'agent' acting within spacetime to bring over the 'information')

... then are we still not forced, nonetheless, to say that the connection is NONLOCAL?

I think so. I think everybody else should think so.

Simon, what do you think? ... What about everybody else?

It sounds like you're imagining a spacelike "link" between the measurement outcome events. Such a "link" would constitute "nonlocality" in the FTL sense. You can avoid drawing such a spacelike link in the nonseparable/holistic view of the events if you include the emission event and connect the emission event with the two detection events by timelike links and consider THAT collection of events to be nonseparable. That's called retrocausality.

 

[Simon Phoenix]

At least one of the instruments must 'know' both the setting and the outcome of the other instrument.

OK - in the post of mine you've quoted above there's a very important 'if' in there. Let's just re-state the position.

IF we want to describe things with variables that have a realistic character THEN we require some non-local (FTL) properties for them, in order to use them to explain the violation of the Bell inequality. There's no escape, no ifs or buts, we are forced into this once we assume this realistic character.

But if one adopts a QM view of things is one forced to think in terms of non-local effects or processes?

Not at all - it rather depends on the interpretation of QM you choose to work with. Have a look at the "Gell Mann on entanglement" thread. Vanhees beautifully explains a consistent interpretation of QM that requires no such 'non-local' thinking to explain what's happening. I'm not fully happy with any interpretation of QM - although I tend to most often think in terms of state collapse where the state has some ontic character - although there are serious problems with this perspective.

Ultimately, so far, ANY of the interpretations of QM will predict the violation - each one will have a different way of 'explaining' it. There is no way, at the moment, that we can say we are forced to adopt any of these particular interpretations as being the 'correct' one.

 

[morrobay]

Here is the spacelike separated setup with detectors A and B about 20 km apart.
I would just ask the question: What is the explanation for the non classical correlations that violate
Bell inequalities that do not include any superluminal signaling in any aspect of experiment ?
Was this information en coded into the entangled particles at the source during their creation ?
What exactly are non local quantum correlations that again are relativistic ?
How does the vanhees71 interpretation answer this at the B level ?

 

[Zafa Pi]

Here is the spacelike separated setup with detectors A and B about 20 km apart.
I would just ask the question: What is the explanation for the non classical correlations that violate
Bell inequalities that do not include any superluminal signaling in any aspect of experiment ?
Was this information en coded into the entangled particles at the source during their creation ?
What exactly are non local quantum correlations that again are relativistic ?
How does the vanhees71 interpretation answer this at the B level ?

The answer to your 1st ? is: There is none. That is Gell-Mann's position and I've not seen anything that convinces me otherwise.*
The answer to your 2nd ? is: No. That would be hidden variables which the violation of Bell's inequality proves is false.
My answer to your 3rd ? is: I'm skeptical like you.

*There are classical phemonena with no explanation as well.

 

[Zafa Pi]

The answer to your 1st ? is: There is none. That is Gell-Mann's position and I've not seen anything that convinces me otherwise.*
The answer to your 2nd ? is: No. That would be hidden variables which the violation of Bell's inequality proves is false.
My answer to your 3rd ? is: I'm skeptical like you.

*There are classical phemonena with no explanation as well.

Actually I like Einstein's answer to the 1st ?: Spooky action at distance.

 

[RUTA]

IF we want to describe things with variables that have a realistic character THEN we require some non-local (FTL) properties for them, in order to use them to explain the violation of the Bell inequality. There's no escape, no ifs or buts, we are forced into this once we assume this realistic character.

You can have locality and realism (CFD) with retrocausality. Of course the CFD is irrelevant given the outcomes and settings are part of the ontological explanation. But, you can paint whatever properties you like on the worldlines in retrocausality and all connections are timelike (no FTL properties). You just have to be willing to consider spatiotemporal (block universe) explanation as fundamental, what Wharton calls Lagrangian Schema explanation (based on least action principles), rather than time-evolved dynamical explanation (mechanical universe), what Smolin calls Newtonian Schema explanation (based on differential equations). This idea is perhaps in keeping with Wilczek's challenge:

A recurring theme in natural philosophy is the tension between the God’s-eye view of reality comprehended as a whole and the ant’s-eye view of human consciousness, which senses a succession of events in time. Since the days of Isaac Newton, the ant’s-eye view has dominated fundamental physics. We divide our description of the world into dynamical laws that, paradoxically, exist outside of time, and initial conditions on which those laws act. The dynamical laws do not determine which initial conditions describe reality. That division has been enormously useful and successful pragmatically, but it leaves us far short of a full scientific account of the world as we know it. The account it gives – things are what they are because they were what they were – raises the question, Why were things that way and not any other? The God’s-eye view seems, in the light of relativity theory, to be far more natural. Relativity teaches us to consider spacetime as an organic whole whose different aspects are related by symmetries that are awkward to express if we insist on carving experience into time slices. Hermann Weyl expressed the organic view memorably in his 1949 book \textit{Philosophy of Mathematics and Natural Science} (Princeton University Press, page 116):

The objective world simply is, it does not happen. Only to the gaze of my consciousness, crawling upward along the life line of my body, does a section of this world come to life as a fleeting image in space which continuously changes in time.

To me, ascending from the ant’s-eye view to the God’s-eye view of physical reality is the most profound challenge for fundamental physics in the next 100 years.

Wilczek, F.: Physics in 100 Years. Physics Today 69(4), 32-39 (2016).

 

[Eye_in_the_Sky]

OK - in the post of mine you've quoted above there's a very important 'if' in there. Let's just re-state the position.

IF we want to describe things with variables that have a realistic character THEN we require some non-local (FTL) properties for them, in order to use them to explain the violation of the Bell inequality. There's no escape, no ifs or buts, we are forced into this once we assume this realistic character.

But if one adopts a QM view of things is one forced to think in terms of non-local effects or processes?

Not at all - it rather depends on the interpretation of QM you choose to work with.

Ah, yes. ... I think I see our point of disagreement.

Consider the statement:

At least one of the instruments KNOWS THE VALUE of both the setting and the outcome of the other instrument.

I am saying that this statement is true no matter what. Otherwise, the quantum correlations cannot happen as they do.

You are saying that when we employ 'realistic variables' in the description, we are forced to accept such a statement. But when we don't do that, the matter is left open and it depends upon interpretation.

... Did I get that right?
_______

Have a look at the "Gell Mann on entanglement" thread. Vanhees beautifully explains a consistent interpretation of QM that requires no such 'non-local' thinking to explain what's happening.

Does anyone have a link to that post?

 

[morrobay]

Ah, yes. ... I think I see our point of disagreement.

Consider the statement:

At least one of the instruments KNOWS THE VALUE of both the setting and the outcome of the other instrument.

I am saying that this statement is true no matter what. Otherwise, the quantum correlations cannot happen as they do.

You are saying that when we employ 'realistic variables' in the description, we are forced to accept such a statement. But when we don't do that, the matter is left open and it depends upon interpretation.

... Did I get that right?
_______

Does anyone have a link to that post?