Quantum decision affects results of measurements taken earlier in time

reply to post by scarystuff


Hi sca,
My advice would be, learn to be less easily entertained.
Take up crafts or engage in sports.
That stuff is pure horsemonges with ribbons.


cheers ljb

reply to post by phishyblankwaters

side note, if you think the results of a test being dependent on a future state is silly, according to Arizona, pregnancy begins 2 weeks BEFORE conception.

well since I been through three pages and see no one else has asked...WTF???
What's up with that, Arizona???
How in the hell does pregnancy start two weeks before conception???
Is this some backwoods white anglo saxon protestant way to ban contraceptives as "abortion" medication???

reply to Cecilofs

The first of your two posts, the one in which you explain your understanding of the experiment, is absolutely perfect, even down to the final conclusion about Newtonian mechanics and our perceptual understanding of the world. There are different ways of looking at these experimental results, but basically you've got the picture fair and square. Well done.

Your second post is more problematic.

consciousness affected the experiment - because the ultimate destination of the measurements are the conscious mind of the scientist.

Sure. If you choose that philosophical tack, you don't need the bizarreness of quantum mechanics to prove your point. The ultimate destination of all measurements – that is to say, all perceived phenomena – is the mind of a human being. To some – Descartes, for example, or Bishop Berkeley – mind is the only reliably real thing, perhaps the only thing that exists. From there is but a short step to insisting that there is only one mind – one's own – and that it creates the whole universe. Idealism and its mad child solipsism are impossible to disprove.

Science begins with the opposite assumption, that there is a real, phenomenal world which presents itself in roughly the same form to all (human) minds. From this was derived a principle, still followed in practice, of scientific objectivity: experimental results could not be tainted by the intervention of the experimenter. Quantum mechanics shows that this kind of detached observation is, at a fundamental level, impossible. For some people, this legitimises idealism, the idea that mind is the only reality, and that consciousness determines the shape and structure of the universe. They talk up quantum paradoxes to justify belief in time travel, remote viewing, telekinesis and just about every other wish-fulfilling fantasy of the superstitious.

That is all very well, of course, but as you now understand, the conscious mind of the scientist has absolutely no control over specific outcomes in the experiment. It cannot force a photon to take a path through slit A or slit B – except, of course, by covering the other slit. It can only discover, after the fact, which slit the photon went through. Mind is not creating this reality; it merely discovers it. There is not one atom of comfort here for silly people who think that merely wishing hard enough makes things come true.

Consider that we are now looking at a larger system with many more variables involved. The system involves the experiment but also the scientist and as you said yourself, in a way, the entire universe. Consider then that the scientist runs the experiment over night like you said, but hasn't looked at the results yet. The experiment itself could now be in a quantum state, like Schrodinger's Cat. The scientist doesn't know what state the results are in until he looks.

This is true, but there is nothing in the experiment itself to suggest that it is. Schrödinger's cat is just a thought-experiment. The life or death of the cat are real and distinct enough to the animal, whatever the notional superposition of these states to someone who hasn't yet looked in the box to see. Even if it weren't an animal – even if it were, say, a lump of some mineral that changes colour when bombarded by radioactive decay products – the thing would or wouldn't have changed colour at some point in time, whether or not somebody was looking at it. In the macroscopic world, entanglement leads to decoherence and all objects behave as we expect them to (unless we really force them to do otherwise, as physicists have recently acquired the ability to do).

Of course the experiment is a quantum system, and can be described by a wavefunction – one that incorporates the wavefunction of the system being measured. And yes, that 'larger' wavefunction is part of a wavefunction still larger, and so on and so forth until we reach the wavefunction of the universe (which some physicists regard as self-evidently static, thereby opening the door to the theoretical abolition of time). This is all very exciting and possibly quite profound, but it really doesn't alter the issue we are discussing. Does consciousness create the world or does the world create consciousness? Or do they somehow exist side by side in parallel but intersecting realities, each influencing and altering the other? Science gives us no help at all with such questions.

Most scientists nowadays are materialists, but not all; and whether they are or not, they are so because of personal inclination, no matter what arguments they may put forward for their beliefs. The evidence is always ambiguous and open to interpretation according to whatever position an individual favours.

To some up: there is no evidence from quantum mechanics that proves consciousness directly creates or manipulates reality.

Thanks for taking the time to explain and respond

Overall I think we agree on the basics but are interpreting the results in a different way. The problem is we can't prove one way or the other, at least not yet.

Originally posted by AstyanaxScience begins with the opposite assumption, that there is a real, phenomenal world which presents itself in roughly the same form to all (human) minds.

Exactly, an assumption which may actually be wrong. We are beginning to see the first evidence that it is wrong IMO.

How about a real world example of this experiment? Let's say Jane and Bill each go to a location on earth that no-one has ever been to before and never will again. Jane and Bill never meet in their lives - was the area they went to the same for both of them? Or is it only the same once Jane and Bill meet and compare experiences? I don't mean that it changes retroactively but as in this experiment what's in that area could be determined by them meeting in the future. Again, of course this is only speculation and there's no way to prove it.

That is all very well, of course, but as you now understand, the conscious mind of the scientist has absolutely no control over specific outcomes in the experiment. It cannot force a photon to take a path through slit A or slit B – except, of course, by covering the other slit. It can only discover, after the fact, which slit the photon went through. Mind is not creating this reality; it merely discovers it. There is not one atom of comfort here for silly people who think that merely wishing hard enough makes things come true.

That's a different experiment then! In this experiment the scientist tried to remain neutral and unbiased (although also impossible) and therefore would not have affected which slit the proton took even if they could. What about an experiment where the scientist expects to see more photons going through the left slit? To my knowledge no-one is looking at things like that, because the assumption is that it can't happen. That assumption may be wrong.

Intent/belief =/= wishful thinking, they are different.

This is true, but there is nothing in the experiment itself to suggest that it is. Schrödinger's cat is just a thought-experiment. The life or death of the cat are real and distinct enough to the animal, whatever the notional superposition of these states to someone who hasn't yet looked in the box to see. Even if it weren't an animal – even if it were, say, a lump of some mineral that changes colour when bombarded by radioactive decay products – the thing would or wouldn't have changed colour at some point in time, whether or not somebody was looking at it.

Which is again an assumption with no way to prove or disprove it, since we can only know by looking in the box. If all reality behaves the same as a quantum system (which at the moment we are not sure of), then it would literally exist in all states at once until being observed by some form of consciousness (we are also assuming here that animals, or perhaps all life can be the observer).

This is all very exciting and possibly quite profound, but it really doesn't alter the issue we are discussing. Does consciousness create the world or does the world create consciousness? Or do they somehow exist side by side in parallel but intersecting realities, each influencing and altering the other? Science gives us no help at all with such questions.

Yes I see that as a problem. What I think is that science, or more to the point the dogma built up around it, needs to start taking a harder look at the assumptions that are being made.

I agree with one of the core principles of science - that to support a theory, you need real world evidence to back it up. You should be able to predictably put that theory into practice in reality. I just think that starting with defintions of "reality" and "evidence" that are solely based in a materialistic world-view isn't correct. Really, considering what we now know about Electro-magnetism, gravity, all sorts of radiation and quantum physics, its amazing that we haven't expanded those definitions already.

To some up: there is no evidence from quantum mechanics that proves consciousness directly creates or manipulates reality.

Correction, there is no scientifically acceptable evidence, because science assumes it is impossible and will not, by definition, ever accept any of that evidence. The experiment actually proves either or both are possible, because we can't differentiate between the machine causing the effect or that the information gets back to the scientist.

Again, it is assumed that it must be the machine and not the scientist's consciousness. That may not be correct.

I would like to see more experiments along this track i.e. whether or not the scientist's thoughts/beliefs/expectations can affect the experiment.

reply to post by Cecilofs

That's all right. You wish to believe in certain phenomena, so you look for evidence of them, and you find it. The evidence may not be scientifically tenable, but it is always possible that the scientific approach is wrong, or based on a misapprehension. Perhaps the scientific approach is intrinsically blind to the phenomena you want to believe in. Well, yes, that could be true. And if you want to believe it is, there is no-one to stop you. Certainly not I.

If we are now agreed that these quantum results do not imply a role for consciousness in determining the outcome of the experiment, there is no further argument between us.

reply to post by michaelbrux


Are you refering to Timewave Zero?

reply to post by Astyanax

Sure. If you choose that philosophical tack, you don't need the bizarreness of quantum mechanics to prove your point. The ultimate destination of all measurements – that is to say, all perceived phenomena – is the mind of a human being. To some – Descartes, for example, or Bishop Berkeley – mind is the only reliably real thing, perhaps the only thing that exists. From there is but a short step to insisting that there is only one mind – one's own – and that it creates the whole universe. Idealism and its mad child solipsism are impossible to disprove.

What does that tell you? Why do we base our entire belief system on something we can't actually prove; reality outside of human perception, and scoff at the notion that we can actually prove?

Science begins with the opposite assumption, that there is a real, phenomenal world which presents itself in roughly the same form to all (human) minds. From this was derived a principle, still followed in practice, of scientific objectivity: experimental results could not be tainted by the intervention of the experimenter. Quantum mechanics shows that this kind of detached observation is, at a fundamental level, impossible. For some people, this legitimises idealism, the idea that mind is the only reality, and that consciousness determines the shape and structure of the universe. They talk up quantum paradoxes to justify belief in time travel, remote viewing, telekinesis and just about every other wish-fulfilling fantasy of the superstitious.

You have yet to explain and debunk the result of the experiments I layed out to you, but you still refuse.

If you believe Remote Viewing is superstition I advise to read this entire thread, you will probably say it was setup, but whatever.

www.abovetopsecret.com...

I think you are living in a fantasy world where everything is normal, explainable and in line with your own views. Wake up, it is not.

That is all very well, of course, but as you now understand, the conscious mind of the scientist has absolutely no control over specific outcomes in the experiment. It cannot force a photon to take a path through slit A or slit B – except, of course, by covering the other slit. It can only discover, after the fact, which slit the photon went through. Mind is not creating this reality; it merely discovers it. There is not one atom of comfort here for silly people who think that merely wishing hard enough makes things come true.

Noone is suggesting you can simply wish your desired reality into existence. reality comes into existence and it always corresponds with what you know at that moment, it's not the same thing.

You can keep saying particles aren't influenced by what we know, but the exp. we were talking about clearly show this, and like I said, you have not debunked them. At this point you are just spreading info that you think is correct but has been proven wrong.

To some up: there is no evidence from quantum mechanics that proves consciousness directly creates or manipulates reality.

Yes, there is and it is very clear. I posted it at least 5 times. You simply refuse to adress the implications. You didn't disprove the claims. Everything you are saying is your opinion and these experiments say you are wrong.

Why else would it matter if Which path info is known, and how can results that already happened in the past "change" to fit what the experimenter knows in the present?

reply to post by Cecilofs

The experiment actually proves either or both are possible, because we can't differentiate between the machine causing the effect or that the information gets back to the scientist.

I think it does prove it, the results always match what the experimenter knows, if it was the machine, then chance would dictate that that result should not correspond with what the experimenter knows all the time, but it always does.

Doesn't that prove it? To me it does.

Originally posted by longjohnbritches
reply to post by scarystuff

 

Hi sca,
My advice would be, learn to be less easily entertained.
Take up crafts or engage in sports.
That stuff is pure horsemonges with ribbons.


cheers ljb

My advice would be, if you have nothing of substance to say, then don't say it. The result of these experiments are there to see, and they are remarkable.

If anything is pure horsemonges with ribbons it is your opinion which is based on nothing. Your advice of ignoring these experiments is ridiculous, and the opposite of helpfull.

reply to post by RandomEsotericScreenname


no, i'm referring to an obvious pattern of events that are occurring exactly 2020 days apart.

i've been tempted to call it the 'Five and a Half Days', a name inspired by a time frame I first read about in the first Book of Adam and Eve.

2020 days is actually 5.53 years making that name somewhat inaccurate.

after think about the experiment mentioned in this thread, it seems that Ron Paul is application in question.

someone is getting ready to do something whereby Ron Paul will become the Republican Nominee and all of the results of the primaries will magically read that Ron Paul won them, even though we all 'know' that he did not.

it'll be interesting to see if it works.

Have you ever heard of Timewave Zero, it also suggests that there are periods in which events are repeated, only with more intensity and increasingly faster.

I'll keep an eye out for what you are saying.

reply to post by RandomEsotericScreenname


I heard about it but also heard that they charge a fee...i'm opposed to paying for things.

i'm expecting a situation where wave-like behavior becomes particle-like behavior and all those that thrive off of uncertainty are going to be very upset...cry a river they will.

Originally posted by RandomEsotericScreenname
reply to post by aboriginee

 

And now I think, you should read my last post once more, which you`ve answered to in the above shown text. That`s what I wrote and what I meant: Although the which-pass-information was there and detected by the first detector, the screen showed already an interference-pattern, although this information of interference was given to the particle after that.

No you simply misunderstood what they actually meant, which becomes obvious if you study the complete experiment.

The particles had already hit the screen when they check the detectors that show either the which path info, or show that the which path info is not known.

In both cases, if they look at the screen after they checked the detectors and know the which path or not, the pattern on the screen always corresponds with what they know, or don't know, even though at the time the particles hit the screen it was still open.

And that`s nothing about consciousness. Quantum-particles don`t act within our time in order to get information, in some regions ore actions they stand above time.

I see, and why do you think they specifically mention what the experimenter knows here?

However, the interference pattern can only be seen retroactively once the idler photons have already been detected and the experimenter has obtained information about them, with the interference pattern being seen when the experimenter looks at particular subsets of signal photons that were matched with idlers that went to particular detectors.

It's obviously about what the experimenter knows.

And something about my citation you posted at the end of your above text: Please don`t cut off my texts - the meaning of my statements could change by doing that.

You mean this line that show that you don't understand the way this exp. is set up?

But in the delayed choise quantum eraser experiment the interference pattern appears, although the particle has been measured. The which-path-information, that simultaniously can be observed on the first detector, will then be erased shortly after that.

The way it is setup, it is impossible to simultaniously see the interference pattern on the screen, and the which path info on the detector and to erase it.

If the idler particle is detected at detectors 1 or 2 there is no which path info that can be determined, if the idler is detected at D3 or D4, then they know which path info. AFTER that, they check the screen and see that the pattern matches with what they have learned from the detectors, even though the particles have hit the screen before the idlers have hit any of the detectors.

edit on 3-5-2012 by RandomEsotericScreenname because: (no reason given)

I really misunderstood something: I thought, there would have been a measurement inbetween. But what I thought to be a measurement is the knowledge of the experimenter, that the which-pass-information of all idlers being measured is originally there, because the prism has sent the idlers to different passes dependent on wether they came from slit A or slit B.

Here again the link to the article in wikipedia

en.wikipedia.org...

And here the most important point or the result in this text:

However, what makes this experiment possibly astonishing is that, unlike in the classic double-slit experiment, the choice of whether to preserve or erase the which-path information of the idler need not be made until after the position of the signal photon has already been measured by D0.

There is never any which-path information determined directly for the photons that are detected at D0, yet detection of which-path information by D3 or D4 means that no interference pattern is observed in the corresponding subset of signal photons at D0.

The results from Kim, et al.[1] have shown that whether the idler photon is detected at a detector that preserves its which-path information (D3 or D4) or a detector that erases its which-path information (D1 or D2) determines whether interference is seen at D0, even though the idler photon is not observed until after the signal photon arrives at D0 due to the shorter optical path for the latter.

The choice of wether to preserve or erase the which-pass-information isn`t made by the experimenter but by the built up apparatures.
The position of the signal photon has already been measured when the idler photon will be observed.

That`s what you`ve got wrong - there is nothing about consciousness.

And in the original very first double-slit experiment with single particles the observer or experimenter never expected that particles would interfere with itself, when both slits were open - but they did - that`s also nothing about consciousness.

reply to post by aboriginee


Oh, yes, particles interfere with themselves - not with itself.

reply to post by scarystuff


This might not mean much to any of you but this is how it's done in my opinion. Take the bicycle wheel for instance.


The center hub is the quantum world. Each spoke is what connects the past, present, future, yourself, strangers and everything that exists in the universe. Nothing is travelling the speed of light or faster. It's just simultaneously connected there. It's all connected. We're trying to figure out what information is being passed, how fast it's going etc. But that's the wrong way of thinking about it. The answer is singularity.

reply to post by aboriginee

The choice of wether to preserve or erase the which-pass-information isn`t made by the experimenter but by the built up apparatures. The position of the signal photon has already been measured when the idler photon will be observed.

Exactly, but I never implied that that choice was made by the experimenter. The point is that he checks at which detector a particular idler has arrived, then he checks the pattern on the screen that was made by the entangled signal particle, and the pattern always corresponds with what he has found out about the idler, even though the signal particle had already made the pattern on the screen before the path of the idler could ever be known.

The result always coresponds with what the experimenter found out about the idler, even though the result should have already happened, and cannot always fit his knowledge just by chance every single time.

The result adapts to what the experimenter knows. It has to, otherwise the reality that we see would not make "sense", lol.

Btw, why would you even call it "Which Path info" if it doesn't matter to a human?

However, the interference pattern can only be seen retroactively once the idler photons have already been detected and the experimenter has obtained information about them, with the interference pattern being seen when the experimenter looks at particular subsets of signal photons that were matched with idlers that went to particular detectors.

Why include the experimenter in this if he has nothing to do with it?

That`s what you`ve got wrong - there is nothing about consciousness.

You guys keep repeating that but none of you have an alternative explanation for these weird results which I have explained over 6 or 7 times now.

Why has noone of the skeptics sofar even acknowledged or even mentioned these wild results. It becomes clear from the article, that no matter how you look at it, these results are extremely weird and remarkable.

What gives? There really is no discussion about that.

You are just focussing on ways to debunk me, yet you skip across the blatantly obvious tell tale signs that say otherwise.

Just because a piece of text describing the process doesn't mention consciousness specifically doesn't mean it is not involved. Every time they mention a detector they are talking about a detector that gets checked by a human at some point of the time in the process.

Ok, let's say it has nothing to do with consciousness, then what is causing these results that should be impossible in our current understanding. What else is it?

And in the original very first double-slit experiment with single particles the observer or experimenter never expected that particles would interfere with itself, when both slits were open - but they did - that`s also nothing about consciousness.

First of all, Young who did the original DS exp. didnt fire SINGLE particles. and even if he did, it doesn't matter what he might or might not have expected, he only saw a result, he wasn't looking what happened before that. and he had no prior result.

In the experiments we are talking about, there is an extra factor, the which path info, which makes only one outcome possible, and this outcome is always in line with what the experimenter knows and has learned, after the result should have already happened.

Think about what I'm saying here, if you see it it makes a lot of sense, and it would explain why quantum events are so weird and defy "time" and lightspeed. It would explain the "faster than light" travel in entanglement.

Very interesting stuff.

Originally posted by RandomEsotericScreenname
reply to post by aboriginee

 

post by aboriginee

 

And in the original very first double-slit experiment with single particles the observer or experimenter never expected that particles would interfere with itself, when both slits were open - but they did - that`s also nothing about consciousness.

First of all, Young who did the original DS exp. didnt fire SINGLE particles. and even if he did, it doesn't matter what he might or might not have expected, he only saw a result, he wasn't looking what happened before that. and he had no prior result.

Yes, but first of all - I wrote nothing about the very first double-slit experiment, but about the very first double-slit-experiment with single particles!

The result adapts to what the experimenter knows. It has to, otherwise the reality that we see would not make "sense", lol.

Reality doesn`t only happen in the way, our every-day-knowledge of physics does. Information between entangled particles, in the experiment the idler- photons and the signal-photons, "travels" without needing time.

Btw, why would you even call it "Which Path info" if it doesn't matter to a human?

The which-path-info is something, that the photon has got. If it is lead through a defined or special path, the wave-function collapses. If it is measured, the wave-function collapses too. When it has got the which-path-info, it ends to be a wave and starts to be a particle.

Ok, let's say it has nothing to do with consciousness, then what is causing these results that should be impossible in our current understanding. What else is it?

If information within entangled particles doesn`t need time to "travel", it doesnt matter, weather there something happened in the past or will happen in the future.

And now I`m finally coming to the sentence out of the article in Wikipedia that you`ve quoted so often:

However, the interference pattern can only be seen retroactively once the idler photons have already been detected and the experimenter has obtained information about them, with the interference pattern being seen when the experimenter looks at particular subsets of signal photons that were matched with idlers that went to particular detectors.

And that you mentioned about so often something like this:

Why include the experimenter in this if he has nothing to do with it?

Now, please, look at the context this sentence is written in and under what headline it has been placed.

Here once more the link to the article in Wikipedia:

en.wikipedia.org...

And here the headline of the chapter under which this sentence appears at the end:

Details pertaining to retrocausality in the Kim experiment

And there is something explained as follows: In order to know which signal-photon belongs to which idler-photon the experimenter has to correlate the signal-photons to the idler-photons and therefore he has to look to the idler-photon first.
His observation is retroactiv to the direction of time in which things happen at the experiment.
That is a problem, if scientists want to use retrocausality.

And here is the directly following headline and the text:

The main stumbling block for using retrocausality to communicate information

The total pattern of signal photons at the primary detector never shows interference, so it is not possible to deduce what will happen to the idler photons by observing the signal photons alone, which would open up the possibility of gaining information faster-than-light (since one might deduce this information before there had been time for a message moving at the speed of light to travel from the idler detector to the signal photon detector) or even gaining information about the future (since as noted above, the signal photons may be detected at an earlier time than the idlers), both of which would qualify as violations of causality in physics. The apparatus under discussion here could not communicate information in a retro-causal manner because it takes another signal, one which must arrive via a process that can go no faster than the speed of light, to sort the superimposed data in the signal photons into four streams that reflect the states of the idler photons at their four distinct detection screens.

In fact, a theorem proved by Phillippe Eberhard shows that if the accepted equations of relativistic quantum field theory are correct, it should never be possible to experimentally violate causality using quantum effects[5] (see reference [6] for a treatment emphasizing the role of conditional probabilities).

It`s about the impossibility of time-travelling within our physica

reply to post by aboriginee

Excuse me, something went wrong, I`m new in here, I`ll try once more!

Originally posted by RandomEsotericScreenname
reply to post by aboriginee

 

post by aboriginee

 

And in the original very first double-slit experiment with single particles the observer or experimenter never expected that particles would interfere with itself, when both slits were open - but they did - that`s also nothing about consciousness.

First of all, Young who did the original DS exp. didnt fire SINGLE particles. and even if he did, it doesn't matter what he might or might not have expected, he only saw a result, he wasn't looking what happened before that. and he had no prior result.

Yes, but first of all - I wrote nothing about the very first double-slit experiment, but about the very first double-slit-experiment with single particles!

The result adapts to what the experimenter knows. It has to, otherwise the reality that we see would not make "sense", lol.

Reality doesn`t only happen in the way, our every-day-knowledge of physics does. Information between entangled particles, in the experiment the idler- photons and the signal-photons, "travels" without needing time.

Btw, why would you even call it "Which Path info" if it doesn't matter to a human?

The which-path-info is something, that the photon has got. If it is lead through a defined or special path, the wave-function collapses. If it is measured, the wave-function collapses too. When it has got the which-path-info, it ends to be a wave and starts to be a particle.

Ok, let's say it has nothing to do with consciousness, then what is causing these results that should be impossible in our current understanding. What else is it?

If information within entangled particles doesn`t need time to "travel", it doesn`t matter, weather there something happened in the past or will happen in the future.

And now I`m finally coming to the sentence out of the article in Wikipedia that you`ve quoted so often:

However, the interference pattern can only be seen retroactively once the idler photons have already been detected and the experimenter has obtained information about them, with the interference pattern being seen when the experimenter looks at particular subsets of signal photons that were matched with idlers that went to particular detectors.

And that you mentioned about so often something like this:

Why include the experimenter in this if he has nothing to do with it?

Now, please, look at the context this sentence is written in and under what headline it has been placed.

Here once more the link to the article in Wikipedia:

en.wikipedia.org...

And here the headline of the chapter under which this sentence appears at the end:

Details pertaining to retrocausality in the Kim experiment

And there is something explained as follows: In order to know which signal-photon belongs to which idler-photon the experimenter has to correlate the signal-photons to the idler-photons and therefore he has to look to the idler-photon first.
His observation is retroactiv to the direction of time in which things happen at the experiment.
That is a problem, if scientists want to use retrocausality.

And here is the directly following headline and the text:

The main stumbling block for using retrocausality to communicate information

The total pattern of signal photons at the primary detector never shows interference, so it is not possible to deduce what will happen to the idler photons by observing the signal photons alone, which would open up the possibility of gaining information faster-than-light (since one might deduce this information before there had been time for a message moving at the speed of light to travel from the idler detector to the signal photon detector) or even gaining information about the future (since as noted above, the signal photons may be detected at an earlier time than the idlers), both of which would qualify as violations of causality in physics. The apparatus under discussion here could not communicate information in a retro-causal manner because it takes another signal, one which must arrive via a process that can go no faster than the speed of light, to sort the superimposed data in the signal photons into four streams that reflect the states of the idler photons at their four distinct detection screens.

In fact, a theorem proved by Phillippe Eberhard shows that if the accepted equations of relativistic quantum field theory are correct, it should never be possible to experimentally violate causality using quantum effects[5] (see reference [6] for a treatment emphasizing the role of conditional probabilities).

It`s about the impossibility for us of travelling in time.