Quantum uncertainty, and Schrodinger's cat

[Kharakov]

Branches grow until trimmed.

Trimmed?

I strayed from MWI, and was speculating that specific branches (worlds) are trimmed when an observer witnesses something (cat is dead or alive, 2 branches). Definitely not a full MW interpretation- instead there are MWs until a specific branch is forced to be chosen by observation.

 

[Angra Mainyu]

Actually I missed that there is a difference between the recording and the cat (or chimp, etc) as I mentioned earlier in the double split experiment. The recording device would collapse the wave function and enable us to identify when (or if) the quantum decay occurred because we would be able to play it back after the box was opened – it wouldn’t be part of the system under test but an observer. The cat (etc.) in the box would be part of the system under test and wouldn’t collapse the wave function because their state is determined by the wave function collapse, not knowable until the box is opened. That is the Copenhagen interpretation. Of course there is disagreement but none of the criticisms or the Copenhagen interpretation itself can be demonstrated, only argued for now. However, the common non-QM disagreements such as “it doesn’t make sense” is just an absurd disagreement that is made from complete ignorance of what the issue is.

First, suppose we had the tech to retrieve data from a cat's brain, so that we can get a recording. Whys is the cat "part of the system", but the camera isn't?

Second, your "etc." after "chimp" seems to imply that if there were a human being in the box, or ten human beings, they too would be "part of the system under test", and so their physical state would also be indefinite. But what determines what is the "system under test", and makes the state indefinite?

Moreover, why would the people inside the box not be able to collapse the wave function of the poison-releasing system?

But there is still a Nobel Prize for you if you can explain in QM terms how the cat (or whatever) will collapse the wave function.

Some interpretations posit collapse. Others do not. I have insufficient knowledge to make an assessment. So, I don't. I have no beliefs on the matter, nor do I make any claims.
Moreover, even if there is collapse, for all I know GRW might be true, or a better approximation than any other hypothesis. Or maybe not. What do I know?

 

[skepticalbip]

First, suppose we had the tech to retrieve data from a cat's brain, so that we can get a recording. Whys is the cat "part of the system", but the camera isn't?

Second, your "etc." after "chimp" seems to imply that if there were a human being in the box, or ten human beings, they too would be "part of the system under test", and so their physical state would also be indefinite. But what determines what is the "system under test", and makes the state indefinite?

Moreover, why would the people inside the box not be able to collapse the wave function of the poison-releasing system?

A good example of an argument that "it doesn't make sense".

But there is still a Nobel Prize for you if you can explain in QM terms how the cat (or whatever) will collapse the wave function.

Some interpretations posit collapse. Others do not. I have insufficient knowledge to make an assessment. So, I don't. I have no beliefs on the matter, nor do I make any claims.
Moreover, even if there is collapse, for all I know GRW might be true, or a better approximation than any other hypothesis. Or maybe not. What do I know?

Now that is a much better statement.

 

[Angra Mainyu]

A good example of an argument that "it doesn't make sense".

I see. So, you don't address the questions (like, why isn't the brain of the cat good enough as a recorder), but say my argument doesn't make sense. Any counterarguments? Anything at all? What about the questions? Could you please address them? (ETA: if the "doesn't make sense" part is about the "poison-releasing mechanism" part, then:
a. That part was a reply mirroring your previous reply in which you seem to put a stress on what system was being observed; if it didn't make sense, the point was that your reply didn't. But maybe I missed what you meant at the time; it's hard to tell given your pattern of avoidance and now outright hostility).
b. Regardless, even if we erased that part of my comment, the rest remains, and you have offered no rational reply - as you have failed to reasonably address my questions and/or objections so far).

Whatever. I can argue against your position anyway, despite your pattern or replies.

So, the chimp can't collapse the wave function, according to you. Let's say so. Neither can a person, apparently. So, let's say that Bob (an adult, normal human) is in the box. There is no poison, but a mechanism that will just blow up a small device covering pretty much everything in the box (including Bob) with tomato juice.

So, Bob is in the box. His state (either covered in tomato juice, or not) is not determined until Alice opens the box. Bob enters the box at t1. Alice opens the box at t2. At (t2+t1)/2, what has Bob actually experienced? Has he experienced being covered in tomato juice, or not?

According to you, apparently there is no answer. But if a recording device is added - that is, another recording device, in addition to Bob's brain -, then there is an answer. He may have experienced being covered in juice for a while, and there is a specific amount of time during which he experienced that.

Do you have any evidence and/or reasons whatsoever in support of your bizarre implication that the brain is not good enough a recording device (i.e., it does not have the power to collapse the wave function and cover him in blood or not), but the camera is? Or is this a matter of faith?

If you're going to tell me that my objection doesn't make sense, then my answer is that of course - very obviously - it does. You're implying that if there is a camera in there, Bob experiences things normally, but if there is not, then there is no definite state, and so no definite answer as to what he observes. I'm saying that your beliefs that have such implication are epistemically improper. That is an objection that makes sense. Do you have a reply that makes sense?

 

[DBT]

Trimmed?

I strayed from MWI, and was speculating that specific branches (worlds) are trimmed when an observer witnesses something (cat is dead or alive, 2 branches). Definitely not a full MW interpretation- instead there are MWs until a specific branch is forced to be chosen by observation.

Isn't every branch of the MW universe supposed to be an expression of every possible outcome regardless of any particular observer? In other words, all of the versions of 'you' being the subjects (or is that articles) of all possible combinations of each and every event in your lifetime?

 

[Juma]

I don't claim to understand quantum weirdness. I just recognize and acknowledge that it is there. If either of you can explain the double slit experiment and/or quantum weirdness, in general, then there is a Nobel Prize waiting for you. Refusing to accept quantum weirdness because you don't understand it (no one does yet) is only refusal to accept reality.

I do not refuse to accept reality. I asked you very specific questions, which you refused to answer. Those answers would almost certainly have led to serious difficulties for some of your ontological beliefs (though your lack of addressing my questions makes it difficult for me to address the matter in detail without considering a zillion options about what your position might be).

If you think somehow I'm making a mistake, then could you please address my questions.

Specifically:

Okay, so the cat's physical state is undefined until the box is opened.
Let's say it's a chimp, rather than a cat.
5. Is the chimp's physical state undefined until the box is opened? If not, what's so special about cats, or chimps?
6. What if it's a human toddler?
7. An adult human?
8. Ten adult humans? (let's stipulate it's a big box in that case).

I will add:

9. Why do you think the device "cat's eyes + relevant parts of the brain" is not an observer, but an infrared camera is?

BECAUSE IT IS A THOUGHT EXPERIMENT! In reality anything that interacts with the cat will collapse the wave. Including the surrounding air. And of course: the interactions going on in the immensly complicated process that is the cat itself.

 

[bilby]

I do not refuse to accept reality. I asked you very specific questions, which you refused to answer. Those answers would almost certainly have led to serious difficulties for some of your ontological beliefs (though your lack of addressing my questions makes it difficult for me to address the matter in detail without considering a zillion options about what your position might be).

If you think somehow I'm making a mistake, then could you please address my questions.

Specifically:

Okay, so the cat's physical state is undefined until the box is opened.
Let's say it's a chimp, rather than a cat.
5. Is the chimp's physical state undefined until the box is opened? If not, what's so special about cats, or chimps?
6. What if it's a human toddler?
7. An adult human?
8. Ten adult humans? (let's stipulate it's a big box in that case).

I will add:

9. Why do you think the device "cat's eyes + relevant parts of the brain" is not an observer, but an infrared camera is?

BECAUSE IT IS A THOUGHT EXPERIMENT! In reality anything that interacts with the cat will collapse the wave. Including the surrounding air. And of course: the interactions going on in the immensly complicated process that is the cat itself.

A THOUGHT experiment?? Does that mean I should take all this equipment back to the shop then? I wonder if I can get a refund on vials of poison gas.

If you know anyone who can give a good home to a cat (which may or may not exist), please let me know...

 

[skepticalbip]

....................
Do you have a reply that makes sense?

Obviously not one that makes sense to you since you don't seem to understand the issue in question for those physicists (not me) who are struggling to understand QM better. Your objections so far are based on your understanding of your "logic" of every day phenomena. A hint, understanding of QM can not be achieved by relating it to every day normal experience.

 

[Juma]

....................
Do you have a reply that makes sense?

Obviously not one that makes sense to you since you don't seem to understand the issue in question for those physicists (not me) who are struggling to understand QM better. Your objections so far are based on your understanding of your "logic" of every day phenomena. A hint, understanding of QM can not be achieved by relating it to every day normal experience.

But you are certainly not helping. The SC is a thought experiment. As soon as the decay has happened there will be interactions en masse that will immediately collapse the wave. That is why we do not see these stuff in our macroscopic life: undisturbed systems are extremely short lived when containing some 10^20 particles....

 

[Wiploc]

According to the famous thought experiment, Schrodinger's Cat exists in a quantum uncertain state until the box is opened, and can thus be both alive and dead.

I've run into someone who insists that this is a logical contradiction, and thus that not only the cat, but quantum uncertainty itself, is impossible.

If you need a good insult, you can tell him, "Hey, buddy, you're as stupid as Einstein and Schrodinger."

 

[Angra Mainyu]

Obviously not one that makes sense to you since you don't seem to understand the issue in question for those physicists (not me) who are struggling to understand QM better. Your objections so far are based on your understanding of your "logic" of every day phenomena. A hint, understanding of QM can not be achieved by relating it to every day normal experience.

No, logic is logic. I'm asking you questions that you repeatedly refuse to answer, and when I consider possibilities (about what you might have meant), you dismiss my reply as nonsensical. I keep raising serious objections to your view (based on the info you gave about it; your reluctance to explain your view makes things more difficult), but you keep failing to see the force of the objections, and replying dismissively.

So, another point:

If part of your assessment (which may or may not be; I'm guessing as you refuse to clarify your claims) is based on whether the camera is outside or inside the box, that does not seem to work, either. It would seem to be an arbitrary choice of system on your part. I explained that earlier, though you considered the explanation nonsensical.
Again and in more details, if you're suggesting that a camera outside the box is an observer and can collapse the wave function because it's outside the box but a camera inside the box is not an observer because it's inside the box and that's part of the system under observation, then I point out that a camera inside the box is also outside the system {poison + poison-releasing mechanism (including particles that are part of the mechanism)}, and so it's an observer with respect to that system, and that's enough to collapse that wave function and release the poison - why wouldn't it?
Why would the relevant system be the system including the whole box?
For that matter, someone might say the system includes a 1 mile radius around the box, so the camera outside the box is stuck in the system. But clearly, that does not work. What someone says is irrelevant. But then, your saying that the system is the whole box (and beyond the {poison + poison-releasing mechanism (including any relevant potentially decaying particles)} would not prevent a camera inside the box (or a chimp) from collapsing the wave function of the smaller system, which the camera (or the chimp) is out of.

 

[Angra Mainyu]

I do not refuse to accept reality. I asked you very specific questions, which you refused to answer. Those answers would almost certainly have led to serious difficulties for some of your ontological beliefs (though your lack of addressing my questions makes it difficult for me to address the matter in detail without considering a zillion options about what your position might be).

If you think somehow I'm making a mistake, then could you please address my questions.

Specifically:

Okay, so the cat's physical state is undefined until the box is opened.
Let's say it's a chimp, rather than a cat.
5. Is the chimp's physical state undefined until the box is opened? If not, what's so special about cats, or chimps?
6. What if it's a human toddler?
7. An adult human?
8. Ten adult humans? (let's stipulate it's a big box in that case).

I will add:

9. Why do you think the device "cat's eyes + relevant parts of the brain" is not an observer, but an infrared camera is?

BECAUSE IT IS A THOUGHT EXPERIMENT! In reality anything that interacts with the cat will collapse the wave. Including the surrounding air. And of course: the interactions going on in the immensly complicated process that is the cat itself.

The only "why" question is 9., so your "because" answer seems to be an answer to that. But the fact that it's a thought experiment has nothing to do with which devices in the thought experiment count as observers. So, your reply is mistaken.

 

[Angra Mainyu]

....................
Do you have a reply that makes sense?

Obviously not one that makes sense to you since you don't seem to understand the issue in question for those physicists (not me) who are struggling to understand QM better. Your objections so far are based on your understanding of your "logic" of every day phenomena. A hint, understanding of QM can not be achieved by relating it to every day normal experience.

A hint: you're not showing your understanding of QM. You're making mistakes and holding beliefs in an epistemically improper manner, without realizing it. Why? Please address my questions and objections and there is a greater chance that you'll see that (not much greater, though; this is an internet debate, and on top of that, there is the specific evidence of your pattern of replies earlier in the thread)

 

[Juma]

BECAUSE IT IS A THOUGHT EXPERIMENT! In reality anything that interacts with the cat will collapse the wave. Including the surrounding air. And of course: the interactions going on in the immensly complicated process that is the cat itself.

The only "why" question is 9., so your "because" answer seems to be an answer to that. But the fact that it's a thought experiment has nothing to do with which devices in the thought experiment count as observers. So, your reply is mistaken.

No it is not.... It is a thought experiment and thus have made some very specific assumptions to simplifyvthe matter. One of those is that the cat itself is not assumed to be an observer.

 

[Angra Mainyu]

The only "why" question is 9., so your "because" answer seems to be an answer to that. But the fact that it's a thought experiment has nothing to do with which devices in the thought experiment count as observers. So, your reply is mistaken.

No it is not.... It is a thought experiment and thus have made some very specific assumptions to simplifyvthe matter. One of those is that the cat itself is not assumed to be an observer.

That's not what skepticalbip is saying. He's saying that a cat, or a chimp, or anything else can't collapse the wave function (i.e., she's not an observer). He's not saying that it's not an observer by assumption. On the other hand, he claims that an infrared camera in the box would collapse the wave function. I'm challenging - among other things - that combination of claims.

 

[skepticalbip]

No it is not.... It is a thought experiment and thus have made some very specific assumptions to simplifyvthe matter. One of those is that the cat itself is not assumed to be an observer.

That's not what skepticalbip is saying. He's saying that a cat, or a chimp, or anything else can't collapse the wave function (i.e., she's not an observer). He's not saying that it's not an observer by assumption. On the other hand, he claims that an infrared camera in the box would collapse the wave function. I'm challenging - among other things - that combination of claims.

I said that the cat or whatever is a part of the system under test, not an observer. That is the assumption of the thought experiment.

I kept hoping that you would actually look up the issue addressed in the thought experiment so you would understand what the argument in physics is about. It is irrelevant what is in the box with the radioactive particle whether a cat, human, chimp or a rock that would have acid dissolve it if the radioactive decay happened. The idea presented in the thought experiment is that the quantum event would become entangled with whatever macro object was there in a superposition until there was an observer. Whatever macro object was there would part of the system under test, not an observer. Your continuing attempt to make it an observer rather than the system under test told me that you hadn’t yet bothered to try to find out what the thought experiment was even about. Of course, there is still argument in physics over how to interpret many QM events, including this one. The creator of the thought experiment (Schrodinger) didn't like the Copenhagen interpretation and offered the thought experiment to illustrate its absurdity. The supporters of the Copenhagen interpretation thought it was a good example of their interpretation and adopted it.

 

[ontological_realist]

That's not what skepticalbip is saying. He's saying that a cat, or a chimp, or anything else can't collapse the wave function (i.e., she's not an observer). He's not saying that it's not an observer by assumption. On the other hand, he claims that an infrared camera in the box would collapse the wave function. I'm challenging - among other things - that combination of claims.

Angra Mainyu! It is written in my holy book that You can take a horse to water but you can not make him drink it, at least not by logic alone.

 

[Angra Mainyu]

I said that the cat or whatever is a part of the system under test, not an observer. That is the assumption of the thought experiment.

And the camera sn't, because you choose not to say that it is?
So, let's say that there are two cats in the box, Garfield and Felix (replace them by humans if you doubt cats can be observers)
Will they be dead/alive?
Your reply seems to imply that if they're both part of the system under test, then yes, they would both be dead/alive. But if only Felix of them is a part of the system under test, then no, because the Garfield collapses the wave function.

But of course, they can be both part of the system labeled "under test" by Bob, but not part of the system labeled "under test" by Alice. And the point is that what set of objects Bob or Alice labels "under test" has nothing to do with what the cats are experiencing, if anything - nothing if they're dead -, or whether they're dead or alive.

For that matter, let's say that Jack and Jill are now in the box. So, you say that the system under test includes Jack and Jill, so they're both dead/alive. But - alas - Jill decided to consider only the system including the rest of the box but herself, so she became and observer, collapsed the wave function, and died - despite the fact that you would keep committed to the belief that she's dead/alive, as your system includes Jill.

For that matter, go back to the single-cat experiment. You say that the cat is part of the system under test. Suppose the experiment is actually carried out, and no one opens the box, but I just declare that the cat is no longer part of the system under test. Then, by what you seem to be saying, I ought to conclude that now the cat collapses the wave function, so it's either dead, or alive.

I kept hoping that you would actually look up the issue addressed in the thought experiment so you would understand what the argument in physics is about. It is irrelevant what is in the box with the radioactive particle whether a cat, human, chimp or a rock that would have acid dissolve it if the radioactive decay happened.

I'm addressing some of your claims, not the claims by some physicists who came up with the experiment, publicly discussed it, etc. And I kept hoping you would actually address my questions and explain your claims.

The idea presented in the thought experiment is that the quantum event would become entangled with whatever macro object was there in a superposition until there was an observer.

But let's say that the macro objects are Jill and Jack. If Jill declares that she's an observer and not part of the system, could she make some wave function collapse and die? Or is it the case that no matter what Jill says (or one of her states says), she's dead/alive?
If it's the latter, then suppose that Dick (who is outside the box) simply declares that Jill is not a part of the system under test. Could that make Jill and observer, collapse a wave function and kill them both?

Whatever macro object was there would part of the system under test, not an observer.

Crucial question given your replies:
What determines what the "system under test" is? Can the people inside the box decide so - thus getting killed? Or are they some quantum weird states incapable of choices?

For example, let's say that Jill and Jack and a camera are inside the box - let's say it's a real box.
So, Linda declares that all three objects are part of the system under test. George declares that Jill and Jack are, but not the camera. Dick says that Jill is not part of the system under test.

After Linda, George and Dick have made their statements, are Jill and Jack dead/alive - their state is indeterminate - or are they not? (side note: if you tell me it depends on the experiment or something like that, I will ask you what you claim is really going on: are Jill and Jake experiencing things, or are they perhaps not (because they died after collapse)?).

Your continuing attempt to make it an observer rather than the system under test told me that you hadn’t yet bothered to try to find out what the thought experiment was even about.

I have, but that is irrelevant, because I'm not replying to the thought experiment as done by some other people. I'm replying to some of your claims about a thought experiment in this thread.

 

[untermensche]

I don't claim to understand quantum weirdness. I just recognize and acknowledge that it is there. If either of you can explain the double slit experiment and/or quantum weirdness, in general, then there is a Nobel Prize waiting for you. Refusing to accept quantum weirdness because you don't understand it (no one does yet) is only refusal to accept reality.

There is double slit weirdness with particles and then there is interpretation on how that weirdness will effect something on the scale of a cat.

All we have is interpretation, not evidence.

 

[skepticalbip]

And the camera sn't, because you choose not to say that it is?

No. I'm saying that the camera isn't because you and Unter- suggested putting it in the box to record for later playback. Which incidentally shows that neither of you understood what the thought experiment was intended to be about.

So, let's say that there are two cats in the box, Garfield and Felix (replace them by humans if you doubt cats can be observers)
Will they be dead/alive?
Your reply seems to imply that if they're both part of the system under test, then yes, they would both be dead/alive. But if only Felix of them is a part of the system under test, then no, because the Garfield collapses the wave function.

But of course, they can be both part of the system labeled "under test" by Bob, but not part of the system labeled "under test" by Alice. And the point is that what set of objects Bob or Alice labels "under test" has nothing to do with what the cats are experiencing, if anything - nothing if they're dead -, or whether they're dead or alive.

For that matter, let's say that Jack and Jill are now in the box. So, you say that the system under test includes Jack and Jill, so they're both dead/alive. But - alas - Jill decided to consider only the system including the rest of the box but herself, so she became and observer, collapsed the wave function, and died - despite the fact that you would keep committed to the belief that she's dead/alive, as your system includes Jill.

For that matter, go back to the single-cat experiment. You say that the cat is part of the system under test. Suppose the experiment is actually carried out, and no one opens the box, but I just declare that the cat is no longer part of the system under test. Then, by what you seem to be saying, I ought to conclude that now the cat collapses the wave function, so it's either dead, or alive.

All illustrating that you still don't understand what the thought experiment is intended to say about quantum uncertainty.

I kept hoping that you would actually look up the issue addressed in the thought experiment so you would understand what the argument in physics is about. It is irrelevant what is in the box with the radioactive particle whether a cat, human, chimp or a rock that would have acid dissolve it if the radioactive decay happened.

I'm addressing some of your claims, not the claims by some physicists who came up with the experiment, publicly discussed it, etc. And I kept hoping you would actually address my questions and explain your claims.

They are not my claims. Personally, I don't particularly care for the Copenhagen interpretation. What I was saying is what the those who do claim would happen in the thought experiment.

The idea presented in the thought experiment is that the quantum event would become entangled with whatever macro object was there in a superposition until there was an observer.

But let's say that the macro objects are Jill and Jack. If Jill declares that she's an observer and not part of the system, could she make some wave function collapse and die? Or is it the case that no matter what Jill says (or one of her states says), she's dead/alive?
If it's the latter, then suppose that Dick (who is outside the box) simply declares that Jill is not a part of the system under test. Could that make Jill and observer, collapse a wave function and kill them both?

Again you are showing that you don't understand the thought experiment and its purpose.

Whatever macro object was there would part of the system under test, not an observer.

Crucial question given your replies:
What determines what the "system under test" is? Can the people inside the box decide so - thus getting killed? Or are they some quantum weird states incapable of choices?

The designer of the thought experiment determines what the system under test is. In this thought experiment, the designers specifically designed the test for the purpose of having the cat as part of the system under test.

For example, let's say that Jill and Jack and a camera are inside the box - let's say it's a real box.
So, Linda declares that all three objects are part of the system under test. George declares that Jill and Jack are, but not the camera. Dick says that Jill is not part of the system under test.

After Linda, George and Dick have made their statements, are Jill and Jack dead/alive - their state is indeterminate - or are they not? (side note: if you tell me it depends on the experiment or something like that, I will ask you what you claim is really going on: are Jill and Jake experiencing things, or are they perhaps not (because they died after collapse)?).

I have no idea what the fuck you are talking about but it has nothing to do with the thought experiment or its intent.

Your continuing attempt to make it an observer rather than the system under test told me that you hadn’t yet bothered to try to find out what the thought experiment was even about.

I have, but that is irrelevant, because I'm not replying to the thought experiment as done by some other people. I'm replying to some of your claims about a thought experiment in this thread.

I have made no personal claims, only described what the thought experiment is about.