Quantum uncertainty, and Schrodinger's cat

[bilby]

I do not think that just the act of opening the box can change the cat's physical state.

You are right. Opening the box does not change the cat's physical state. Opening the box collapses the wave function so establishes the cat's physical state which was undefined before that.

Opening the box should be done with great caution, as Terry Pratchett pointed out in Lords and Ladies:

Technically, a cat locked in a box may be alive or it may be dead. You never know until you look. In fact, the mere act of opening the box will determine the state of the cat, although in this case there were three determinate states the cat could be in: these being Alive, Dead, and Bloody Furious.

 

[Juma]

I do not think that just the act of opening the box can change the cat's physical state.

You are right. Opening the box does not change the cat's physical state. Opening the box collapses the wave function so establishes the cat's physical state which was undefined before that.

Nah. The wave functipn will collapse long before anyone opens the box.

 

[Angra Mainyu]

You are right. Opening the box does not change the cat's physical state. Opening the box collapses the wave function so establishes the cat's physical state which was undefined before that.

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?
6. What if it's a toddler?
7. An adult human?
8. Ten adult humans? (let's stipulate it's a big box in that case).

 

[untermensche]

Does all this happen because we open the box or because we look in the box?

 

[DBT]

Many world interpretation restores Determinism, all possible outcomes are expressed as objects and progressions of events. There is no Wave Collapse.

 

[Speakpigeon]

You wrote, "so the reality described by QM and referred to by Feynman can only be that our intuition that the cat is either dead or alive even before the box is opened is wrong."

Are you saying that quantum reality is like that or are you saying that all reality is like that?

I'm talking about the description of reality by QM (as I understand it), not reality itself. You'll remember I say we don't know the material world so I'm not going to contradict myself pretending I know that reality is like this or like that.

In the standard interpretation, QM isn't about the whole of reality, only about the probabilities of future events. I will guess that many scientists would like to go beyond that and say something about reality in between interactions but since they also seem to disagree among themselves in radical ways we'll have to wait a bit that the dust settles.

If you are saying that this is how all reality is then that would mean that if you knew some body five years ago then that person today is neither dead nor alive unless you see him.

Part of my answer is already in the quote you're replying to:

In the case of Schrödinger's cat before the box is opened, QM doesn't describe the current (or actual) state of any cat but the probabilities of the various states of the cat once the box is opened.

So if it's a person who is placed inside a Schrödinger box, then the standard interpretation of QM neither says that there's actually a dead person nor that there's a person alive inside the box once it's closed and the experiment is started. QM just tells you the probabilities of possible future events on opening the box such as finding the person alive or finding the person dead. If we're talking about QM, it seems that's all we can say. That's a bit unnerving but that's it.

If we are not talking about macroscopic events inside a Schrödinger box then most of the time I think it will be too complicated to predict anything with QM. And as to what the reality is, me I just don't know. Once you start looking into QM I think you get very conservative about predicting anything beyond experiments that are rather simple and limited compare to our experience of everyday life. Broadly, we're back to our intuitions about how the macroscopic wolrd works.
EB

 

[Speakpigeon]

Does all this happen because we open the box or because we look in the box?

Because of whichever comes first...

As I understand it, as the box is opened the universe outside immediately interacts with the inside so that there are no longer probabilities, only one state. But it seems you can't say that the cat is dead (or alive as the case may be) because of the opening the door. What is caused by the opening of the door is the fact that you can now observe what is inside the box and see a dead cat (or one alive).
EB

 

[fromderinside]

Does all this happen because we open the box or because we look in the box?

Because of whichever comes first...

As I understand it, as the box is opened the universe outside immediately interacts with the inside so that there are no longer probabilities, only one state. But it seems you can't say that the cat is dead (or alive as the case may be) because of the opening the door. What is caused by the opening of the door is the fact that you can now observe what is inside the box and see a dead cat (or one alive).
EB

I'm not wrapping my arms around a solution designed to explain what its like to be working with stuff that is smaller in time or space than we can measure being used to propose something about the nature of matter and energy itself?

 

[Valjean]

Size is relative. Physics is universal

 

[ontological_realist]

I'm talking about the description of reality by QM (as I understand it), not reality itself. You'll remember I say we don't know the material world so I'm not going to contradict myself pretending I know that reality is like this or like that.

In the standard interpretation, QM isn't about the whole of reality, only about the probabilities of future events. I will guess that many scientists would like to go beyond that and say something about reality in between interactions but since they also seem to disagree among themselves in radical ways we'll have to wait a bit that the dust settles.

If you are saying that this is how all reality is then that would mean that if you knew some body five years ago then that person today is neither dead nor alive unless you see him.

Part of my answer is already in the quote you're replying to:

In the case of Schrödinger's cat before the box is opened, QM doesn't describe the current (or actual) state of any cat but the probabilities of the various states of the cat once the box is opened.

So if it's a person who is placed inside a Schrödinger box, then the standard interpretation of QM neither says that there's actually a dead person nor that there's a person alive inside the box once it's closed and the experiment is started. QM just tells you the probabilities of possible future events on opening the box such as finding the person alive or finding the person dead. If we're talking about QM, it seems that's all we can say. That's a bit unnerving but that's it.

If we are not talking about macroscopic events inside a Schrödinger box then most of the time I think it will be too complicated to predict anything with QM. And as to what the reality is, me I just don't know. Once you start looking into QM I think you get very conservative about predicting anything beyond experiments that are rather simple and limited compare to our experience of everyday life. Broadly, we're back to our intuitions about how the macroscopic wolrd works.
EB

Thank you EB for your very clear and exact answer.
As you said, "I'm talking about the description of reality by QM (as I understand it), not reality itself. You'll remember I say we don't know the material world so I'm not going to contradict myself pretending I know that reality is like this or like that."

That clarifies the matter for me.

 

[ontological_realist]

I have a few questions.

1. Are you saying that before opening the box, the cat's physical state was not determined? If not, what happens after the box is opened?
2. Would the experiment work in the same way if, instead of a cat, we put a chimp in the box?
3. What if it's an adult human being in the box? And a human newborn?
4. Would it work in the same way if it's a big box, with 100 adult humans in it?

How about we put an infrared camera in the box and the recording can't be viewed until after the box is open.

Will we see a dead and an alive cat randomly as we watch the recording? Will there be multiple recordings?

You have presented a very interesting situation untermensche! I hope your point is answered by some one.

.

 

[skepticalbip]

How about we put an infrared camera in the box and the recording can't be viewed until after the box is open.

Will we see a dead and an alive cat randomly as we watch the recording? Will there be multiple recordings?

You have presented a very interesting situation untermensche! I hope your point is answered by some one.

.

The recording device is an observer. Just as in the double slit experiments, if a device is placed to monitor which slit the electron passes through to be played back later, the interference pattern will no longer be seen. The pattern on the screen will be what would be expected from particles rather than waves. Remove the monitor and the pattern on the screen will be the interference pattern expected if electrons were waves rather than particles. This experiment has been done innumerable times with the same result.

So a monitor in the box to record what happened (for later playback) is the same as opening the box.

 

[Angra Mainyu]

The recording device is an observer. Just as in the double slit experiments, if a device is placed to monitor which slit the electron passes through to be played back later, the interference pattern will no longer be seen. The pattern on the screen will be what would be expected from particles rather than waves. Remove the monitor and the pattern on the screen will be the interference pattern expected if electrons were waves rather than particles.

The recording device is an observer. Is the recording device "cat's eyes + cat's brain" not an observer?
In any case, I would like to ask you what happens if it's not a cat but a chimp, a human, etc. The lack of replies on your part make it difficult for me to assess your points without considering a zillion options about what you may be saying.

Do you think that at some point between our latest common ancestor with cats, there was a first being born with the power to collapse wave functions, even though her parents have no such power?
Sounds kinda like X-Men to me, but in any case, how did the parents' state become determined, given the lack of any entities with the power to collapse wave functions before that?
Or is it the case that some simpler entities - say, some insects - also have the power to collapse wave functions - just as recording devices like cameras do -, but for some reason cats do not have that power?

 

[ontological_realist]

You have presented a very interesting situation untermensche! I hope your point is answered by some one.

.

The recording device is an observer. Just as in the double slit experiments, if a device is placed to monitor which slit the electron passes through to be played back later, the interference pattern will no longer be seen. The pattern on the screen will be what would be expected from particles rather than waves. Remove the monitor and the pattern on the screen will be the interference pattern expected if electrons were waves rather than particles. This experiment has been done innumerable times with the same result.

So a monitor in the box to record what happened (for later playback) is the same as opening the box.

1. How about a monitor in the box to record (not for later playback)?

2. Would you consider a flea on the cat an observer?


.

 

[skepticalbip]

The recording device is an observer. Just as in the double slit experiments, if a device is placed to monitor which slit the electron passes through to be played back later, the interference pattern will no longer be seen. The pattern on the screen will be what would be expected from particles rather than waves. Remove the monitor and the pattern on the screen will be the interference pattern expected if electrons were waves rather than particles.

The recording device is an observer. Is the recording device "cat's eyes + cat's brain" not an observer?
In any case, I would like to ask you what happens if it's not a cat but a chimp, a human, etc. The lack of replies on your part make it difficult for me to assess your points without considering a zillion options about what you may be saying.

Do you think that at some point between our latest common ancestor with cats, there was a first being born with the power to collapse wave functions, even though her parents have no such power?
Sounds kinda like X-Men to me, but in any case, how did the parents' state become determined, given the lack of any entities with the power to collapse wave functions before that?
Or is it the case that some simpler entities - say, some insects - also have the power to collapse wave functions - just as recording devices like cameras do -, but for some reason cats do not have that power?

The recording device is an observer. Just as in the double slit experiments, if a device is placed to monitor which slit the electron passes through to be played back later, the interference pattern will no longer be seen. The pattern on the screen will be what would be expected from particles rather than waves. Remove the monitor and the pattern on the screen will be the interference pattern expected if electrons were waves rather than particles. This experiment has been done innumerable times with the same result.

So a monitor in the box to record what happened (for later playback) is the same as opening the box.

1. How about a monitor in the box to record (not for later playback)?

2. Would you consider a flea on the cat an observer?
.

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.

 

[Angra Mainyu]

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?

 

[skepticalbip]

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?

You missed my first sentence along with the content of the entire post. No one understands quantum weirdness but it, nontheless is reality.

Explain in detail why a chimp (or anything else) would be different (if you believe they would be different and they turn out to be) than a recording device and pick up your Nobel Prize.

 

[fromderinside]

Size is relative. Physics is universal

So getting relative measures in physics is universal. Unfortunately when one cannot measure, its beyond either our capability, or its beyond the ability to use our material universe to measure, we set up engineering models. QM is an engineering model.

 

[Angra Mainyu]

You missed my first sentence along with the content of the entire post. No one understands quantum weirdness but it, nontheless is there.

Explain in detail why a chimp (or anything else) would be different (if you believe they would be different and they turn out to be) than a recording device and pick up your Nobel Prize.

I missed nothing. You continue to refuse to answer.
I do not claim that a chimp would be different from a recording device. I see no good reason to believe it would be.
However you seem to imply that a cat (and specifically, the cat's eyes + brain) is different from a specific recording device (namely, an infrared camera), because the camera (in your view; in reality, there are intepretations that don't even include any collapse) has the power to collapse wave functions, but the cat does not.

Moreover, you seem to imply that a cat is different from a human being, because the human has the power to collapse wave functions, but the cat does not. That leads to the extremely improbable X-Men scenario that I pointed out earlier. Or even worse, because how do you start the collapse?

Now, if my interpretation of your claims is correct, could you please defend the implications I just explained above?
If, on the other hand, my interpretation is mistaken, what's my mistake?

 

[skepticalbip]

You missed my first sentence along with the content of the entire post. No one understands quantum weirdness but it, nontheless is there.

Explain in detail why a chimp (or anything else) would be different (if you believe they would be different and they turn out to be) than a recording device and pick up your Nobel Prize.

I missed nothing. You continue to refuse to answer.
I do not claim that a chimp would be different from a recording device. I see no good reason to believe it would be.
However you seem to imply that a cat (and specifically, the cat's eyes + brain) is different from a specific recording device (namely, an infrared camera), because the camera (in your view; in reality, there are intepretations that don't even include any collapse) has the power to collapse wave functions, but the cat does not.

Moreover, you seem to imply that a cat is different from a human being, because the human has the power to collapse wave functions, but the cat does not. That leads to the extremely improbable X-Men scenario that I pointed out earlier. Or even worse, because how do you start the collapse?

Now, if my interpretation of your claims is correct, could you please defend the implications I just explained above?
If, on the other hand, my interpretation is mistaken, what's my mistake?

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.

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