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Schrodinger's Cat and the Many Worlds Theory

stubs
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8/10/2014 11:08:44 AM
Posted: 2 years ago
For those that spend time studying quantum mechanics (I do not) I was wondering if you could explain the jump made from the Schrodinger's cat thought experiment, to the many worlds hypothesis, and what consequence it has on what we know about the universe? Thanks.
Rational_Thinker9119
Posts: 9,054
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8/10/2014 11:54:30 AM
Posted: 2 years ago
At 8/10/2014 11:08:44 AM, stubs wrote:
For those that spend time studying quantum mechanics (I do not) I was wondering if you could explain the jump made from the Schrodinger's cat thought experiment, to the many worlds hypothesis, and what consequence it has on what we know about the universe? Thanks.

Basically, the quantum system obeys Shrodinger's equation until an observation is made according to orthodox quantum theory (The Copenhagen interpretation). With the MW interpretation however, the system obeys Shrodiner's equation even after an apparent wave-function collapse. As far as the thought experiment goes with regards to the MW interpretation; the cat would be alive in one universe and dead in another with no wave-function collapse. If you open the box and the cat is dead, that just means that you just so happened to be in the universe where the cat was dead (and the cat was dead the whole time), instead of the cat being being in a fuzzy non-collapsed state in the same universe until you looked and actually collapsing the wave-function to the definite form (which is what orthodox quantum theory states).
stubs
Posts: 1,887
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8/10/2014 12:55:50 PM
Posted: 2 years ago
At 8/10/2014 11:54:30 AM, Rational_Thinker9119 wrote:
At 8/10/2014 11:08:44 AM, stubs wrote:
For those that spend time studying quantum mechanics (I do not) I was wondering if you could explain the jump made from the Schrodinger's cat thought experiment, to the many worlds hypothesis, and what consequence it has on what we know about the universe? Thanks.

Basically, the quantum system obeys Shrodinger's equation until an observation is made according to orthodox quantum theory (The Copenhagen interpretation). With the MW interpretation however, the system obeys Shrodiner's equation even after an apparent wave-function collapse. As far as the thought experiment goes with regards to the MW interpretation; the cat would be alive in one universe and dead in another with no wave-function collapse. If you open the box and the cat is dead, that just means that you just so happened to be in the universe where the cat was dead (and the cat was dead the whole time), instead of the cat being being in a fuzzy non-collapsed state in the same universe until you looked and actually collapsing the wave-function to the definite form (which is what orthodox quantum theory states).

Appreciate the response bro. Do you find the many worlds hypothesis compelling and if so what are some of the reasons? Furthermore, could you possibly explain how we know superposition to be a real thing if the phenomenon can not be observed?
Rational_Thinker9119
Posts: 9,054
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8/10/2014 5:22:35 PM
Posted: 2 years ago
At 8/10/2014 12:55:50 PM, stubs wrote:
At 8/10/2014 11:54:30 AM, Rational_Thinker9119 wrote:
At 8/10/2014 11:08:44 AM, stubs wrote:
For those that spend time studying quantum mechanics (I do not) I was wondering if you could explain the jump made from the Schrodinger's cat thought experiment, to the many worlds hypothesis, and what consequence it has on what we know about the universe? Thanks.

Basically, the quantum system obeys Shrodinger's equation until an observation is made according to orthodox quantum theory (The Copenhagen interpretation). With the MW interpretation however, the system obeys Shrodiner's equation even after an apparent wave-function collapse. As far as the thought experiment goes with regards to the MW interpretation; the cat would be alive in one universe and dead in another with no wave-function collapse. If you open the box and the cat is dead, that just means that you just so happened to be in the universe where the cat was dead (and the cat was dead the whole time), instead of the cat being being in a fuzzy non-collapsed state in the same universe until you looked and actually collapsing the wave-function to the definite form (which is what orthodox quantum theory states).

Appreciate the response bro. Do you find the many worlds hypothesis compelling and if so what are some of the reasons?

I don't find it compelling but Physicists like Sean Carrol do. He doesn't like the idea that a quantum system just stops obeying Shrodinger's equation after an observation. He finds it simpler to just assume the quantum system always obeys it; which leads you do the MW interpretation. Also, the MW interpretation is compatible with materialism (which is attractive to scientists), while the orthodox interpretation, at least prima facie; isn't. The Problem of Probability seems to defeat the MW interpretation though, at least based on my knowledge. The Bohm Interpretation is the one favored by many philosophers of religion (such as Quentin Smith and William Lane Craig), but that is way too ad hoc (there is 0 evidence for Bohmian particles, we just have to accept they exist for the theory to work) and clearly just designed to dodge quantum weirdness.

Furthermore, could you possibly explain how we know superposition to be a real thing if the phenomenon can not be observed?

Well, we can do a double-slit diffraction with particles... If there are no superpositions then that would be literally nonsense. So, we can rest assured they exist.
stubs
Posts: 1,887
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8/11/2014 1:25:03 AM
Posted: 2 years ago
At 8/10/2014 5:22:35 PM, Rational_Thinker9119 wrote:
At 8/10/2014 12:55:50 PM, stubs wrote:
At 8/10/2014 11:54:30 AM, Rational_Thinker9119 wrote:
At 8/10/2014 11:08:44 AM, stubs wrote:
For those that spend time studying quantum mechanics (I do not) I was wondering if you could explain the jump made from the Schrodinger's cat thought experiment, to the many worlds hypothesis, and what consequence it has on what we know about the universe? Thanks.

Basically, the quantum system obeys Shrodinger's equation until an observation is made according to orthodox quantum theory (The Copenhagen interpretation). With the MW interpretation however, the system obeys Shrodiner's equation even after an apparent wave-function collapse. As far as the thought experiment goes with regards to the MW interpretation; the cat would be alive in one universe and dead in another with no wave-function collapse. If you open the box and the cat is dead, that just means that you just so happened to be in the universe where the cat was dead (and the cat was dead the whole time), instead of the cat being being in a fuzzy non-collapsed state in the same universe until you looked and actually collapsing the wave-function to the definite form (which is what orthodox quantum theory states).

Appreciate the response bro. Do you find the many worlds hypothesis compelling and if so what are some of the reasons?

I don't find it compelling but Physicists like Sean Carrol do. He doesn't like the idea that a quantum system just stops obeying Shrodinger's equation after an observation. He finds it simpler to just assume the quantum system always obeys it; which leads you do the MW interpretation. Also, the MW interpretation is compatible with materialism (which is attractive to scientists), while the orthodox interpretation, at least prima facie; isn't. The Problem of Probability seems to defeat the MW interpretation though, at least based on my knowledge. The Bohm Interpretation is the one favored by many philosophers of religion (such as Quentin Smith and William Lane Craig), but that is way too ad hoc (there is 0 evidence for Bohmian particles, we just have to accept they exist for the theory to work) and clearly just designed to dodge quantum weirdness.

Furthermore, could you possibly explain how we know superposition to be a real thing if the phenomenon can not be observed?

Well, we can do a double-slit diffraction with particles... If there are no superpositions then that would be literally nonsense. So, we can rest assured they exist.

I'll have to do some reading up in order to adequately understand your responses. Thanks again for the response. I don't know much about this, but I'm hoping to learn.
Sidewalker
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8/11/2014 8:08:31 AM
Posted: 2 years ago
At 8/10/2014 11:08:44 AM, stubs wrote:
For those that spend time studying quantum mechanics (I do not) I was wondering if you could explain the jump made from the Schrodinger's cat thought experiment, to the many worlds hypothesis,

Fundamentally, the jump made was to confuse the tools of science with the substance of science. Schrodinger's wave equation involves the probabilistic evolution of the wave function which leaves us with an unanswered question commonly referred to as the measurement problem, which is why and how does the wave function "collapses" to a single outcome upon measurement or observation.

MWI claims to resolve the measurement problem by simply denying it. The wave equation is a tool of science, a mathematical abstraction developed to help us explain reality, what MWI does is invert that to make the equation what is real, and make reality contingent upon the equation. It says that everything and anything that could ever have happened in the past, did happen, and everything and everything that could happen in the future, will happen. It's an interpretation that has absolutely no retrodictive or predictive power whatsoever, it puts forth a theory that provides everything and anything as an outcome, isn't testable, and has no explanatory or functional value at all.

and what consequence it has on what we know about the universe? Thanks.

It has no epistemological consequence at all. Logically, it denies the most fundamental axioms of logic by crapping all over the law of identity and the law of non-contradiction. In effect it says that everything is both infinitely true and infinitely false, rendering both logic and truth irrelevant. It also denies the most fundamental laws of physics, rendering things like cause and effect, induction, empiricism, and the laws of conservation, meaningless.

But hey, other than all that, it's a great theory :)
"It is one of the commonest of mistakes to consider that the limit of our power of perception is also the limit of all there is to perceive." " C. W. Leadbeater
Rational_Thinker9119
Posts: 9,054
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8/11/2014 11:06:19 AM
Posted: 2 years ago
At 8/11/2014 8:08:31 AM, Sidewalker wrote:
At 8/10/2014 11:08:44 AM, stubs wrote:
For those that spend time studying quantum mechanics (I do not) I was wondering if you could explain the jump made from the Schrodinger's cat thought experiment, to the many worlds hypothesis,

Fundamentally, the jump made was to confuse the tools of science with the substance of science. Schrodinger's wave equation involves the probabilistic evolution of the wave function which leaves us with an unanswered question commonly referred to as the measurement problem, which is why and how does the wave function "collapses" to a single outcome upon measurement or observation.

MWI claims to resolve the measurement problem by simply denying it. The wave equation is a tool of science, a mathematical abstraction developed to help us explain reality, what MWI does is invert that to make the equation what is real, and make reality contingent upon the equation. It says that everything and anything that could ever have happened in the past, did happen, and everything and everything that could happen in the future, will happen. It's an interpretation that has absolutely no retrodictive or predictive power whatsoever, it puts forth a theory that provides everything and anything as an outcome, isn't testable, and has no explanatory or functional value at all.

It not being testable is debatable. David Deutsch (one of the originators of Quantum Computation) believes it is.


and what consequence it has on what we know about the universe? Thanks.

It has no epistemological consequence at all. Logically, it denies the most fundamental axioms of logic by crapping all over the law of identity and the law of non-contradiction. In effect it says that everything is both infinitely true and infinitely false, rendering both logic and truth irrelevant.

In logic you can qualify statements to avoid contradictions... Take a dalmatian, it is both black and non-black (white). That isn't a contradiction if you say some parts are black, and other parts are non-black. With the MW interpretation, something's are true in some universes that are false in other but that's not a contradiction it doesn't seem like to me.

It also denies the most fundamental laws of physics, rendering things like cause and effect, induction, empiricism, and the laws of conservation, meaningless.

Expand on that, because I don't see how this is true.


But hey, other than all that, it's a great theory :)

It's not a good interpretation of QM, I agree with you there.
CanWeKnow
Posts: 217
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8/11/2014 12:46:02 PM
Posted: 2 years ago
It also denies the most fundamental laws of physics, rendering things like cause and
effect, induction, empiricism, and the laws of conservation, meaningless.

Well, in general Quantum Mechanics takes a giant crap on fundamental physics and our understanding of reality, correct?

That's why some of the best physicists in recent times have been obsessed with finding a unifying theory.
Sidewalker
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8/13/2014 10:43:27 PM
Posted: 2 years ago
At 8/11/2014 11:06:19 AM, Rational_Thinker9119 wrote:
At 8/11/2014 8:08:31 AM, Sidewalker wrote:
At 8/10/2014 11:08:44 AM, stubs wrote:
For those that spend time studying quantum mechanics (I do not) I was wondering if you could explain the jump made from the Schrodinger's cat thought experiment, to the many worlds hypothesis,

Fundamentally, the jump made was to confuse the tools of science with the substance of science. Schrodinger's wave equation involves the probabilistic evolution of the wave function which leaves us with an unanswered question commonly referred to as the measurement problem, which is why and how does the wave function "collapses" to a single outcome upon measurement or observation.

MWI claims to resolve the measurement problem by simply denying it. The wave equation is a tool of science, a mathematical abstraction developed to help us explain reality, what MWI does is invert that to make the equation what is real, and make reality contingent upon the equation. It says that everything and anything that could ever have happened in the past, did happen, and everything and everything that could happen in the future, will happen. It's an interpretation that has absolutely no retrodictive or predictive power whatsoever, it puts forth a theory that provides everything and anything as an outcome, isn't testable, and has no explanatory or functional value at all.

It not being testable is debatable. David Deutsch (one of the originators of Quantum Computation) believes it is.

Nonsense, David Deutsch put forth nothing but a thought experiment and he was just conjuring with numbers and game theory, he laid out a complex mathematical process of strictly theoretical circular reasoning that boils down to:

1)If MWI is true there will be an infinite number of universes but we would only be consciously aware of one of them.
2)We are only consciously aware of one universe, so MWI must be true.

That is not logically valid by any stretch of the imagination.

Everett himself thought and almost every physicist that isn"t trying to sell a book to the gullible public agrees, including Deutsch, that there is no experimental way, even in principle, to distinguish between MWI and Copenhagen. Deutsch only dreams that maybe someday, in some probabilistic way, perhaps, we will come up with one, some day.

and what consequence it has on what we know about the universe? Thanks.

It has no epistemological consequence at all. Logically, it denies the most fundamental axioms of logic by crapping all over the law of identity and the law of non-contradiction. In effect it says that everything is both infinitely true and infinitely false, rendering both logic and truth irrelevant.

In logic you can qualify statements to avoid contradictions... Take a dalmatian, it is both black and non-black (white). That isn't a contradiction if you say some parts are black, and other parts are non-black. With the MW interpretation, something's are true in some universes that are false in other but that's not a contradiction it doesn't seem like to me.

It also denies the most fundamental laws of physics, rendering things like cause and effect, induction, empiricism, and the laws of conservation, meaningless.

Expand on that, because I don't see how this is true.

Expand on that, because I don't see how this is true.
Think about it. A theory that says every possible past action has occurred, and every possible outcome will occur, leaves no foundation upon which to base cause and effect. It leaves no basis for inductive reasoning to progress from particular/individual instances to broader generalizations when every instance is said to have occurred, and every generalization about possible effect is said to occur. The foundation of empiricism is that knowledge is based on experience and evidence, MWI denies the very principle of empiricism by postulating infinite universes outside of experience and evidence. A theory that postulates the creation of entire universes upon each probabilistic outcome of every quantum event is just thumbing its nose at the laws of conservation.

MWI has the tail on the wrong end of the dog. It takes Schr"dinger's abstract wave function equation to be objective reality, and makes the universe it probabilistically attempts to describe into an abstraction. It simply trades the mystery of wave function collapse for the mystery of why we are only aware of, or conscious of only one of an infinite number of universes, and in the process, it violates all of the most basic principles of logic and science while solving for nothing whatsoever.

But hey, other than all that, it's a great theory :)

It's not a good interpretation of QM, I agree with you there.
"It is one of the commonest of mistakes to consider that the limit of our power of perception is also the limit of all there is to perceive." " C. W. Leadbeater
Sidewalker
Posts: 3,713
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8/13/2014 11:02:35 PM
Posted: 2 years ago
At 8/11/2014 11:06:19 AM, Rational_Thinker9119 wrote:
At 8/11/2014 8:08:31 AM, Sidewalker wrote:
At 8/10/2014 11:08:44 AM, stubs wrote:
For those that spend time studying quantum mechanics (I do not) I was wondering

Missed this...

In logic you can qualify statements to avoid contradictions... Take a dalmatian, it is both black and non-black (white). That isn't a contradiction if you say some parts are black, and other parts are non-black. With the MW interpretation, something's are true in some universes that are false in other but that's not a contradiction it doesn't seem like to me.

Keep in mind, we aren't just talking about parallel universes, we are talking about entire universes popping into existence. The law of identity isn't broken if there are just different cats in different universes, but it' is broken when you put one cat in the box, and that cat splits into two cats, one that' s alive, and another that is dead, and the law of non-contradiction says the one cat is either alive or dead, not both.
"It is one of the commonest of mistakes to consider that the limit of our power of perception is also the limit of all there is to perceive." " C. W. Leadbeater
Rational_Thinker9119
Posts: 9,054
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8/14/2014 12:50:18 AM
Posted: 2 years ago
At 8/13/2014 11:02:35 PM, Sidewalker wrote:
At 8/11/2014 11:06:19 AM, Rational_Thinker9119 wrote:
At 8/11/2014 8:08:31 AM, Sidewalker wrote:
At 8/10/2014 11:08:44 AM, stubs wrote:
For those that spend time studying quantum mechanics (I do not) I was wondering

Missed this...

In logic you can qualify statements to avoid contradictions... Take a dalmatian, it is both black and non-black (white). That isn't a contradiction if you say some parts are black, and other parts are non-black. With the MW interpretation, something's are true in some universes that are false in other but that's not a contradiction it doesn't seem like to me.

Keep in mind, we aren't just talking about parallel universes, we are talking about entire universes popping into existence. The law of identity isn't broken if there are just different cats in different universes, but it' is broken when you put one cat in the box, and that cat splits into two cats, one that' s alive, and another that is dead, and the law of non-contradiction says the one cat is either alive or dead, not both.

But once it splits it is not just one cat anymore anymore... So, I don't see how any logical laws are broken. There is a cat that is dead in one universe, and a cat that is alive in another. Leibniz Law would tell us that they cannot be the same cat, as there are properties one has that that other one doesn't.
Sidewalker
Posts: 3,713
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8/14/2014 10:05:00 PM
Posted: 2 years ago
At 8/14/2014 12:50:18 AM, Rational_Thinker9119 wrote:
At 8/13/2014 11:02:35 PM, Sidewalker wrote:
At 8/11/2014 11:06:19 AM, Rational_Thinker9119 wrote:
At 8/11/2014 8:08:31 AM, Sidewalker wrote:
At 8/10/2014 11:08:44 AM, stubs wrote:
For those that spend time studying quantum mechanics (I do not) I was wondering

Missed this...

In logic you can qualify statements to avoid contradictions... Take a dalmatian, it is both black and non-black (white). That isn't a contradiction if you say some parts are black, and other parts are non-black. With the MW interpretation, something's are true in some universes that are false in other but that's not a contradiction it doesn't seem like to me.

Keep in mind, we aren't just talking about parallel universes, we are talking about entire universes popping into existence. The law of identity isn't broken if there are just different cats in different universes, but it' is broken when you put one cat in the box, and that cat splits into two cats, one that' s alive, and another that is dead, and the law of non-contradiction says the one cat is either alive or dead, not both.

But once it splits it is not just one cat anymore anymore... So, I don't see how any logical laws are broken.

Once it splits? That isn"t trivial, there is one cat, the law of identity says A=A, and it becomes two cats, now A=2A, how is that a logical progression? The one cat is now in two different states, how exactly does that come about? It isn"t valid to invoke magic and call it logic, you can"t just say magic happens and poof, the cat is two different cats, and therefore no logical laws are broken. That isn"t valid reasoning.

There is a cat that is dead in one universe, and a cat that is alive in another.

Yeah, after the magic there is, but tell me this, which one is the original cat? Which universe is the one we started with, and where exactly did the other universe come from? Both universes have the same past until the magic point at which they split, which one is a different universe? Where did it come from?

Leibniz Law would tell us that they cannot be the same cat, as there are properties one has that that other one doesn't.

Leibniz" law doesn"t prohibit movement does it? The property of your position in space changes in time, but that doesn"t mean you are not the same person who existed one second ago does it? Of course not, Leibniz" law says two items can have all the same properties except for their spatial coordinates and different spatial coordinates means there are two separate items. So spatially, where are the two cats relative to each other, and to the first cat? Where are the two universes, what is their spatial position relative to each other, and to the originating universe? If they are overlapping in some mysterious way, then Leibniz" law says all the stuff outside of the room with the cat in it, has the same properties, so there aren"t two universes, just two cats, but if there is one universe with two cats, where are they, and why can I only see one of them? Does the first cat still exist? Which subsequent cat is continuous with the first cat, and which isn"t? If you can"t answer that, and you can"t, then you are back to having one cat in two different states, and the law of non-contradiction has been violated.

If you think it through, Leibniz" Law actually says they can"t be two different cats, under MWI the cat had properties that made it a single cat, after a quantum event that cat is no longer a cat, it is two cats with mutually exclusive properties, it has violated Leibniz" law of continuity, his law of Identity/Contradiction, and his law of sufficient reason, what exactly is the sufficient reason that one cat existed and now two cats exist? MW doesn"t provide a reason, it just asserts that it happens, and there is no logic to it.

MWI says we don"t know why or how the wave function collapses, so let"s just say it doesn"t collapse and instead let"s say entire universes just come into existence. OK, but I say we don"t know how or why entire universes come into existence, so let"s just say they don"t and instead, let"s say we still need to try to understand the wave function collapse. That is more logical.
"It is one of the commonest of mistakes to consider that the limit of our power of perception is also the limit of all there is to perceive." " C. W. Leadbeater