Peter Mole
- 49
- 3
Peter,
First, just thanks again for your patience and attention to detail. I really do appreciate people like you who take the time to engage with people and do this kind of work in forums.
I may get caught up in my own thinking and ask the same question again but it's not intentional. Other times, I'm certain I'm being redundant at this point in my questions, but I am locking this down if you'll just indulge me a little longer. Furthermore, keep in my that I do not know the language of the math and so in places where the math explains it straightfowardly, I'm still not seeing it and am trying to come at it from other angles.
Part of the reason I spent so much time talking about "observable" or "in front of you" really happening reality vs. "what's really happening" behind the scenes is that at times in our conversation I thought I was doing the former when you thought I was doing the later. Other times, I thought I doing the former but might have been doing the later. For me, breaking up these two concepts of "what's really happening," and not letting them bleed into each other has been a fundamental step to keeping myself sober.
Anyway, a few more questions...
#1. What do you call a deer with no eyes?
answer: no idea (say with boston accent)
I'm probably asking the same thing over and over but that's only because I'm confused. I really am trying to nail it down.
Let's say there's a plane flying high above the clouds and my only instrument for detecting it is radar. The radar turns on and off momentarily and I have an image of where the plane is. We have no other way of detecting the plane. We don't know where it is anytime before or after the moment we detected it on radar. We can say in the common way, given what we know of how radar works, that "in reality" at the moment we detected it a physical object there were the radar said it was.
First, in this situation, is it allowable to say "There's a object in the sky where radar detected it." ?
Of course I'm comparing this to:
Again I come back to... when the detector rings to indicate it's detected the electron.. what can be said about the electron? Can we say we in that moment we knew it's position the same way we knew the position of the plane? I'm guessing your answer is still no. In the common way of planes and radar, what can we cay about what's really happening in the moment? Again, I'm guessing you're going to say nothing.
Part of the issue here is how we use language. In my imagination, it's much easier for me accept we can't say anything about what's really happening with the electron outside the times when we are measuring is (such as when it's on route to the double slits or after it's on the other side).
When you say the "electron changes from wave to particle", it sounds like you're talking about what's really happening, or otherwise making a statement about a physical object or even teh conversion of a "state," but is that just a description and not a comment on an aspect of reality?
Of your two sentences above, is not the first also nothing more than a mathematical description? If not, please explain.
In talking about the two double slit experiments, one without and one with the detectors, you state the only thing you accept as observable reality is the screen at the back that shows the pattern. Say there's a LED light that flashes when the which-way detector identifies an electron. Isn't that also a form of observable reality... of what's really happening in the moment? We can say the LED light went off. Can we say the detector identified an electron? Can we say at the moment the LED light went off, there was an electron passing by in front of the detector? How is this different from saying we detected the mass of the electron (just as we detected the plane using radar) and so therefore in that moment we know the electron "really was" there in physical particle form?
I can accept that the QWF is just a description of an electron and not a statement on reality itself. It's just a math equation we used (retroactively) to explain what happenings in experiments like the double slit at moments like where the detector lights up.
Sorry, in this case I meant technically. Are the detectors looking at the slits like a laser on either side of a garage door seeing if anything's in the way before the door fully closes, or is more like a screen that the election must pass through if it's going through the slit? I'm curious if you could explain this both in hardware and in what's happening on the subatomic level. In other words.. a photon is hitting the electron and bouncing back to the detector, etc.
Let me put my cards on the table. I'm made a list of things I'm struggling to comprehend. At times these things seems to all be referring to the same thing. Part of the confusion is just how we use language. Can you address the differences here in this list or at least use it as a guide to better understand the terms I'm struggling with.
1) electron wave changing to a particle
2) applying Rule 7 to make correct prediction
3) a measurement
4) a record
5) a physical interaction
6) an observation
7) a human observation
9) a pattern on the screen at the end of the double slit experiment
10) a LED indicator going off on the which-way detector indicating it's identified an electron
Okay here's along segment just to get something off the table in my thinking and understanding of what you're saying...
To be crystal and redundantly clear... you would NOT say the same thing about the radar and the plane right? The radar my not know for certain it's a "plane" but at least for the radar we can say we know the thing that the radar is detecting is real. In terms of knowing what something is, we know the thing detected by the radar is an object. Right? I say all this just to make sure we aren't playing philosophical existential mind games. For example, I can say I see a coffee cup sitting right side up on my desk, but physically, due to the lenses in my eyes, what I'm really seeing is the image upside down and my brain flips it over for me. And physically, I'm not seeing the coffee cup where it is, I'm seeing it where it was because the photons didn't instantly hit my eyes. It took time for them to travel to my eyes and in that tiny fraction of a moment the coffee cup was in a different position from where I thought I saw it.
My point is, we could state making existential arguments about macroscopic objects and get super technical about physical attributes and what existing in space-time really means, etc.. You could say a macroscopic mountain is in front of you and I could starting taking existential stuff to argue if it was really "there".
But when you say we can't say the electron is "really there", or is there, you're not engaging in this kind of existential whataboutism, right? That's not what's going here.
Also, even if there's no other way to detect it, I could use Netwtonian math to pinpoint the location of Halley's comet far out on the edge of our solar system. It's totally allowable for me to say it's there even though the only reason I can say this is because of math. Right?When it comes to describing the electron as physically "there in reality" at the time it's detected by the which-way detector... you're saying we can't make this statement. Is this because:
1) The very existential nature of "things" at the quantum level is such that we just can't say they "exist".
2) The very existential nature of "things" at the quantum level is such that we just can't say they "exist" or "not exist" because the term just doesn't apply.
3) The math doesn't say the electron is "there" not because you can't use the math to describe something exists at some point in reality (as with halley's comet), but because QW math is used retroactively. Unlike math used predictively, it's math used after the fact simply to describe what happened.
So in terms of our discussion, when you say it's not an allowable question to ask if it's really there, you're reason is always #3, or just sometime #3?
Again to be redundantly clear, this is not a case of you just arbitrarily limiting the scope of the topic. It's a case where the math, for whatever reason, is only being good for so much and nothing more either by it's scope or by the way in which it's required to be applied. How do I say it... If you have a hypothetical carton containing a dozen eggs and your friend eats two of them and I ask you how many are left, you would say 10. But if I tell you wait.. Here's the basic rules. You're only allowed to use the mathematical rules of addition and multiplication, but not subtraction. Then you could say there's no way to say how many eggs are left because the basic rules don't allow you to answer the question.
Coming at it another way... in the case again of math describing Halley's comet, math can tell us where it is and how fast it's going. Math can tell us what it is. But math can't tell us whether or not an alien spaceship watching it go by thinks the comet is "pretty." What I'm trying to say is, with QWF math describing the electron, it's NOT a case that we are trying to describe an aspect of the electron that's out of bounds for the math to tell us (like whether or not the electron is "pretty") but rather it's all about the fact that the equations are applies after the fact because we don't know (except through experimentation) where the "electron changes from wave to particle". Right?
I think I'm starting to get it. This must be of the stuff no commonly understood by pop-science or those like myself who are math-challenged.
I'm still having trouble wrapping my mind around this. It's like learning how to build a house only from trial and error never knowing if it will stand until it's built and then never really learning anything about the process enough to apply your knowledge to a different kind of house. If you want to know it will stand you can only build the same kind of house. If you design a different kind of house you again won't know if it can stand until it's done, but then at least you'll have another blueprint you understand.
I can now better understand why it must be so hard to build a quantum computer through this kind of trial and error.
Thanks for helping me to realize this bizarre aspect Pete. My mind spins. This is why I came here. (Now please don't tell me I've totally misunderstood it. lol)
I still get hung up when qualify it by say "from first principles" the theory cannot tell us what happens. To beat a dead horse, you can argue that the theory can tell us what happens without the "from first principles" qualification, but to do so you have to move into the realm of speculation. (many worlds, etc)
First, for our topic in this forum, it's fine to talk about when rule 7 is triggered during the double slit experiment. But if we want to start saying rule 7 is triggered by a "physical interaction" then that's speculation and needs to go to a different subforum... Right?
It seems more grounded to say that something physical bumped into something else physical. But you've been firmly and honestly rigid on this for our whole conversation, especially in terms of what we are allowed and not allowed to say. Regarding whatever it was that triggered the use of rule 7, is speculation that it's caused by a "physical interaction" just as valid as speculating that "an invisible purple octopus god poked it from another dimension"? Is it just as valid as speculating that "information was collected by a human" or "another world split off"?
You're offering an opinion and I strongly disagree. I think a lot of people either have an agenda or their understanding is crystalized (in good faith) from their world view. In myself, I'm working hard to get to the understanding that we don't know what's going on in cases where rule 7 is applied, full stop. I certainly don't think most people start there and just fill in a term to avoid the laborious explanation.
Also, can you elaborate on why you qualified with "specifically" instead of just saying "we don't know what's going on?" And furthermore, what can be said about what's "generally" going on?
Would this also be considered speculation? I was of the understanding that "interaction" is a QT term describing the point at which rule 7 was applied. I'm not sure if interaction means "real stuff" hitting "real stuff" or subatomic particles hitting subatomic particles or quantum waves hitting quantum waves. And if it is quantum waves hitting quantum waves is that just a description used by the math?
I know I'm backtracking. Now that you've taught me the places where I can't ask "what's really happening" I'm turning that lens back on statements others have made about QT and seeing if my understanding still holds.
First, just thanks again for your patience and attention to detail. I really do appreciate people like you who take the time to engage with people and do this kind of work in forums.
I may get caught up in my own thinking and ask the same question again but it's not intentional. Other times, I'm certain I'm being redundant at this point in my questions, but I am locking this down if you'll just indulge me a little longer. Furthermore, keep in my that I do not know the language of the math and so in places where the math explains it straightfowardly, I'm still not seeing it and am trying to come at it from other angles.
Part of the reason I spent so much time talking about "observable" or "in front of you" really happening reality vs. "what's really happening" behind the scenes is that at times in our conversation I thought I was doing the former when you thought I was doing the later. Other times, I thought I doing the former but might have been doing the later. For me, breaking up these two concepts of "what's really happening," and not letting them bleed into each other has been a fundamental step to keeping myself sober.
Anyway, a few more questions...
#1. What do you call a deer with no eyes?
answer: no idea (say with boston accent)
But observable reality does not include things like an electron changing from a wave to a particle. Nor does it include things in our mathematical models, like wave functions. So if we are going to limit discussion to just observable reality, we're pretty much done, since we already agree on what the observable reality is: there is an interference pattern with no which-way detectors, and there is not when which-way detectors are present.
I'm probably asking the same thing over and over but that's only because I'm confused. I really am trying to nail it down.
Let's say there's a plane flying high above the clouds and my only instrument for detecting it is radar. The radar turns on and off momentarily and I have an image of where the plane is. We have no other way of detecting the plane. We don't know where it is anytime before or after the moment we detected it on radar. We can say in the common way, given what we know of how radar works, that "in reality" at the moment we detected it a physical object there were the radar said it was.
First, in this situation, is it allowable to say "There's a object in the sky where radar detected it." ?
Of course I'm comparing this to:
But observable reality does not include things like an electron changing from a wave to a particle.
Again I come back to... when the detector rings to indicate it's detected the electron.. what can be said about the electron? Can we say we in that moment we knew it's position the same way we knew the position of the plane? I'm guessing your answer is still no. In the common way of planes and radar, what can we cay about what's really happening in the moment? Again, I'm guessing you're going to say nothing.
But observable reality does not include things like an electron changing from a wave to a particle. Nor does it include things in our mathematical models, like wave functions.
Part of the issue here is how we use language. In my imagination, it's much easier for me accept we can't say anything about what's really happening with the electron outside the times when we are measuring is (such as when it's on route to the double slits or after it's on the other side).
When you say the "electron changes from wave to particle", it sounds like you're talking about what's really happening, or otherwise making a statement about a physical object or even teh conversion of a "state," but is that just a description and not a comment on an aspect of reality?
Of your two sentences above, is not the first also nothing more than a mathematical description? If not, please explain.
So if we are going to limit discussion to just observable reality, we're pretty much done, since we already agree on what the observable reality is: there is an interference pattern with no which-way detectors, and there is not when which-way detectors are present.
In talking about the two double slit experiments, one without and one with the detectors, you state the only thing you accept as observable reality is the screen at the back that shows the pattern. Say there's a LED light that flashes when the which-way detector identifies an electron. Isn't that also a form of observable reality... of what's really happening in the moment? We can say the LED light went off. Can we say the detector identified an electron? Can we say at the moment the LED light went off, there was an electron passing by in front of the detector? How is this different from saying we detected the mass of the electron (just as we detected the plane using radar) and so therefore in that moment we know the electron "really was" there in physical particle form?
I can accept that the QWF is just a description of an electron and not a statement on reality itself. It's just a math equation we used (retroactively) to explain what happenings in experiments like the double slit at moments like where the detector lights up.
That's because I can't, since nobody knows that. I've already said that. If we knew how, physically, a which-way detector made it necessary to apply Rule 7 to make correct predictions, we would be able to tell, from first principles, what physical objects and what physical configurations would do that. And, as I've already said, we can't tell.(You still haven't described the physically of how that works.)
Sorry, in this case I meant technically. Are the detectors looking at the slits like a laser on either side of a garage door seeing if anything's in the way before the door fully closes, or is more like a screen that the election must pass through if it's going through the slit? I'm curious if you could explain this both in hardware and in what's happening on the subatomic level. In other words.. a photon is hitting the electron and bouncing back to the detector, etc.
Let me put my cards on the table. I'm made a list of things I'm struggling to comprehend. At times these things seems to all be referring to the same thing. Part of the confusion is just how we use language. Can you address the differences here in this list or at least use it as a guide to better understand the terms I'm struggling with.
1) electron wave changing to a particle
2) applying Rule 7 to make correct prediction
3) a measurement
4) a record
5) a physical interaction
6) an observation
7) a human observation
9) a pattern on the screen at the end of the double slit experiment
10) a LED indicator going off on the which-way detector indicating it's identified an electron
Okay here's along segment just to get something off the table in my thinking and understanding of what you're saying...
Yes. I have not denied any of this. But knowing that something happened does not tell us what that something is.,..Something IS really happening and whatever is happening is happening because the detectors were added to the experiment and the reason I know SOMETHING REALLY HAPPENED is because the pattern changed from an interference pattern to a double bar.
To be crystal and redundantly clear... you would NOT say the same thing about the radar and the plane right? The radar my not know for certain it's a "plane" but at least for the radar we can say we know the thing that the radar is detecting is real. In terms of knowing what something is, we know the thing detected by the radar is an object. Right? I say all this just to make sure we aren't playing philosophical existential mind games. For example, I can say I see a coffee cup sitting right side up on my desk, but physically, due to the lenses in my eyes, what I'm really seeing is the image upside down and my brain flips it over for me. And physically, I'm not seeing the coffee cup where it is, I'm seeing it where it was because the photons didn't instantly hit my eyes. It took time for them to travel to my eyes and in that tiny fraction of a moment the coffee cup was in a different position from where I thought I saw it.
My point is, we could state making existential arguments about macroscopic objects and get super technical about physical attributes and what existing in space-time really means, etc.. You could say a macroscopic mountain is in front of you and I could starting taking existential stuff to argue if it was really "there".
But when you say we can't say the electron is "really there", or is there, you're not engaging in this kind of existential whataboutism, right? That's not what's going here.
Also, even if there's no other way to detect it, I could use Netwtonian math to pinpoint the location of Halley's comet far out on the edge of our solar system. It's totally allowable for me to say it's there even though the only reason I can say this is because of math. Right?When it comes to describing the electron as physically "there in reality" at the time it's detected by the which-way detector... you're saying we can't make this statement. Is this because:
1) The very existential nature of "things" at the quantum level is such that we just can't say they "exist".
2) The very existential nature of "things" at the quantum level is such that we just can't say they "exist" or "not exist" because the term just doesn't apply.
3) The math doesn't say the electron is "there" not because you can't use the math to describe something exists at some point in reality (as with halley's comet), but because QW math is used retroactively. Unlike math used predictively, it's math used after the fact simply to describe what happened.
So in terms of our discussion, when you say it's not an allowable question to ask if it's really there, you're reason is always #3, or just sometime #3?
Because the basic rules don't answer them. So if you want to stick to the basic rules (which was the condition I gave for such questions being out of bounds), then such questions have no answers, which means it's pointless to even ask them, which means here at PF they are out of bounds in such discussions to avoid pointlessly wasting everyone's time.I don't understand why such questions are out of bounds.
Again to be redundantly clear, this is not a case of you just arbitrarily limiting the scope of the topic. It's a case where the math, for whatever reason, is only being good for so much and nothing more either by it's scope or by the way in which it's required to be applied. How do I say it... If you have a hypothetical carton containing a dozen eggs and your friend eats two of them and I ask you how many are left, you would say 10. But if I tell you wait.. Here's the basic rules. You're only allowed to use the mathematical rules of addition and multiplication, but not subtraction. Then you could say there's no way to say how many eggs are left because the basic rules don't allow you to answer the question.
Coming at it another way... in the case again of math describing Halley's comet, math can tell us where it is and how fast it's going. Math can tell us what it is. But math can't tell us whether or not an alien spaceship watching it go by thinks the comet is "pretty." What I'm trying to say is, with QWF math describing the electron, it's NOT a case that we are trying to describe an aspect of the electron that's out of bounds for the math to tell us (like whether or not the electron is "pretty") but rather it's all about the fact that the equations are applies after the fact because we don't know (except through experimentation) where the "electron changes from wave to particle". Right?
Yes, in scenarios where we already know when we need to apply Rule 7, because either we've tested that scenario before, or we make a correct guess at when to apply it based on some heuristic rule derived from past empirical data....certainly quantum theory can and has been used predictively?
I think I'm starting to get it. This must be of the stuff no commonly understood by pop-science or those like myself who are math-challenged.
I'm still having trouble wrapping my mind around this. It's like learning how to build a house only from trial and error never knowing if it will stand until it's built and then never really learning anything about the process enough to apply your knowledge to a different kind of house. If you want to know it will stand you can only build the same kind of house. If you design a different kind of house you again won't know if it can stand until it's done, but then at least you'll have another blueprint you understand.
I can now better understand why it must be so hard to build a quantum computer through this kind of trial and error.
Thanks for helping me to realize this bizarre aspect Pete. My mind spins. This is why I came here. (Now please don't tell me I've totally misunderstood it. lol)
If QM were able to predict from first principles when to apply Rule 7, experimenters would not have been surprised by things like which-way detectors taking away the interference pattern the first time it was tried. The whole reason such things are so surprising is that the theory cannot tell us from first principles when they will happen.
I still get hung up when qualify it by say "from first principles" the theory cannot tell us what happens. To beat a dead horse, you can argue that the theory can tell us what happens without the "from first principles" qualification, but to do so you have to move into the realm of speculation. (many worlds, etc)
"Physical interactions" is a vague term. Clearly, as you yourself have remarked, there must be something about the which-way detectors that makes it necessary to apply Rule 7, and "physical interactions" is as good a vague term for whatever that something is as anything else.If we don't know how to determine which physical interactions trigger rule 7 (the collapsing of the math wave function), then how do we even know physical interactions play any role at all?
First, for our topic in this forum, it's fine to talk about when rule 7 is triggered during the double slit experiment. But if we want to start saying rule 7 is triggered by a "physical interaction" then that's speculation and needs to go to a different subforum... Right?
"physical interactions" is as good a vague term for whatever that something is as anything else.
It seems more grounded to say that something physical bumped into something else physical. But you've been firmly and honestly rigid on this for our whole conversation, especially in terms of what we are allowed and not allowed to say. Regarding whatever it was that triggered the use of rule 7, is speculation that it's caused by a "physical interaction" just as valid as speculating that "an invisible purple octopus god poked it from another dimension"? Is it just as valid as speculating that "information was collected by a human" or "another world split off"?
When people say "physical interactions", they are not saying they have anything specific in mind. They are just using a convenient label to avoid having to laboriously explain every time that we don't know what specifically is going on.
You're offering an opinion and I strongly disagree. I think a lot of people either have an agenda or their understanding is crystalized (in good faith) from their world view. In myself, I'm working hard to get to the understanding that we don't know what's going on in cases where rule 7 is applied, full stop. I certainly don't think most people start there and just fill in a term to avoid the laborious explanation.
Also, can you elaborate on why you qualified with "specifically" instead of just saying "we don't know what's going on?" And furthermore, what can be said about what's "generally" going on?
Here's a line I pulled from wiki... (ya, I know, it's wiki)
In quantum mechanics, wave function collapse occurs when a wave function—initially in a superposition of several eigenstates—reduces to a single eigenstate due to interaction with the external world. "
Would this also be considered speculation? I was of the understanding that "interaction" is a QT term describing the point at which rule 7 was applied. I'm not sure if interaction means "real stuff" hitting "real stuff" or subatomic particles hitting subatomic particles or quantum waves hitting quantum waves. And if it is quantum waves hitting quantum waves is that just a description used by the math?
I know I'm backtracking. Now that you've taught me the places where I can't ask "what's really happening" I'm turning that lens back on statements others have made about QT and seeing if my understanding still holds.
Last edited: