>> As far as I know despite lots of talk about it I'm STILL the only one on the list that has actually read Carroll's new book, but he gave an excellent Google talk about it on Friday so maybe his critics will at least watch that; after all even an abbreviated Cliff Notes knowledge of a book is better than no knowledge at all.
> Even this video, I don't think, will change Jim Baggott's view.
The Schrödinger equation provides a way to calculate the wave function of a system and how it changes dynamically in time. However, the Schrödinger equation does not directly say what, exactly, the wave function is. Interpretations of quantum mechanics address questions such as what the relation is between the wave function, the underlying reality, and the results of experimental measurements.
An important aspect is the relationship between the Schrödinger equation and wave function collapse. In the oldest Copenhagen interpretation, particles follow the Schrödinger equation except during wave function collapse, during which they behave entirely differently. The advent of quantum decoherence theory allowed alternative approaches (such as the Everett many-worlds interpretation and consistent histories), wherein the Schrödinger equation is always satisfied, and wave function collapse should be explained as a consequence of the Schrödinger equation.
In 1952, Erwin Schrödinger gave a lecture during which he commented,
David Deutsch regarded this as the earliest known reference to a many-worlds interpretation of quantum mechanics, an interpretation generally credited to Hugh Everett III,[ while Jeffrey A. Barrett took the more modest position that it indicates a "similarity in ... general views" between Schrödinger and Everett.
> I watched a little of Sean's talk at Google. It is a very slick marketing exercise -- reminded me of a con man, or a snake oil salesman. Too slick by half.
> I watched most of the lecture, and was put off by the style and the lack of substance.
On Tuesday, October 8, 2019 at 12:35:25 PM UTC-5, Brent wrote:
On 10/8/2019 12:10 AM, Bruce Kellett wrote:
On Tue, Oct 8, 2019 at 10:13 AM Lawrence Crowell <goldenfield...@gmail.com> wrote:
On Monday, October 7, 2019 at 4:21:27 PM UTC-5, John Clark wrote:As far as I know dispite lots of talk about it I'm STILL the only one on the list that has actually read Carroll's new book, but he gave an excellent Google talk about it on Friday so maybe his critics will at least watch that; after all even an abbreviated Cliff Notes knowledge of a book is better than no knowledge at all.
John K Clark
I have read Carroll and Sebens' paper on this, which is more rigorous and less qualitative. I honestly do not have a yay or nay opinion on this. It is something to store away in the mental toolbox. Quantum interpretations are to my thinking unprovable theoretically and not falsifiable empirically.
I watched a little of Sean's talk at Google. It is a very slick marketing exercise -- reminded me of a con man, or a snake oil salesman. Too slick by half.
What do you think he's selling? I think Carroll is a good speaker, a good popularizer, and a nice guy. I feel fortunate to have him representing physics to the public. He is not evangelizing for some particular interpretation and he recognizes that there are alternative interpretations of QM even though he favors MWI.
Also, he's the only scientist who debated William Lane Craig and won by every measure.
Brent
Sean Carroll reminds me more of Alvin Plantinga
who can take math and pull out God.
Carroll makes the big mistake of a number of physics "popularizers" today. He takes the mathematical language of a physical theory (or one version* of that theory, as there are multiple formulations of quantum theory) and pulls a physical ontology out of his math.
The math is not the territory.
* The Schrödinger equation is not the only way to study quantum mechanical systems and make predictions. The other formulations of quantum mechanics include matrix mechanics, introduced by Werner Heisenberg, and the path integral formulation, developed chiefly by Richard Feynman. Paul Dirac incorporated matrix mechanics and the Schrödinger equation into a single formulation.
The Schrödinger equation provides a way to calculate the wave function of a system and how it changes dynamically in time. However, the Schrödinger equation does not directly say what, exactly, the wave function is. Interpretations of quantum mechanics address questions such as what the relation is between the wave function, the underlying reality, and the results of experimental measurements.
On 10/8/2019 11:21 AM, Philip Thrift wrote:
On Tuesday, October 8, 2019 at 12:35:25 PM UTC-5, Brent wrote:
On 10/8/2019 12:10 AM, Bruce Kellett wrote:
On Tue, Oct 8, 2019 at 10:13 AM Lawrence Crowell <goldenfield...@gmail.com> wrote:
On Monday, October 7, 2019 at 4:21:27 PM UTC-5, John Clark wrote:As far as I know dispite lots of talk about it I'm STILL the only one on the list that has actually read Carroll's new book, but he gave an excellent Google talk about it on Friday so maybe his critics will at least watch that; after all even an abbreviated Cliff Notes knowledge of a book is better than no knowledge at all.
John K Clark
I have read Carroll and Sebens' paper on this, which is more rigorous and less qualitative. I honestly do not have a yay or nay opinion on this. It is something to store away in the mental toolbox. Quantum interpretations are to my thinking unprovable theoretically and not falsifiable empirically.
I watched a little of Sean's talk at Google. It is a very slick marketing exercise -- reminded me of a con man, or a snake oil salesman. Too slick by half.
What do you think he's selling? I think Carroll is a good speaker, a good popularizer, and a nice guy. I feel fortunate to have him representing physics to the public. He is not evangelizing for some particular interpretation and he recognizes that there are alternative interpretations of QM even though he favors MWI.
Also, he's the only scientist who debated William Lane Craig and won by every measure.
Brent
Sean Carroll reminds me more of Alvin Plantinga
who can take math and pull out God.
Carroll makes the big mistake of a number of physics "popularizers" today. He takes the mathematical language of a physical theory (or one version* of that theory, as there are multiple formulations of quantum theory) and pulls a physical ontology out of his math.
That's why it's called an "interpretation". Every physical theory has an ontology that goes with it's mathematics, otherwise you don't know how to apply the mathematics.
On Tuesday, October 8, 2019 at 1:40:33 PM UTC-6, Brent wrote:
On 10/8/2019 11:21 AM, Philip Thrift wrote:
On Tuesday, October 8, 2019 at 12:35:25 PM UTC-5, Brent wrote:
On 10/8/2019 12:10 AM, Bruce Kellett wrote:
On Tue, Oct 8, 2019 at 10:13 AM Lawrence Crowell <goldenfield...@gmail.com> wrote:
On Monday, October 7, 2019 at 4:21:27 PM UTC-5, John Clark wrote:As far as I know dispite lots of talk about it I'm STILL the only one on the list that has actually read Carroll's new book, but he gave an excellent Google talk about it on Friday so maybe his critics will at least watch that; after all even an abbreviated Cliff Notes knowledge of a book is better than no knowledge at all.
John K Clark
I have read Carroll and Sebens' paper on this, which is more rigorous and less qualitative. I honestly do not have a yay or nay opinion on this. It is something to store away in the mental toolbox. Quantum interpretations are to my thinking unprovable theoretically and not falsifiable empirically.
I watched a little of Sean's talk at Google. It is a very slick marketing exercise -- reminded me of a con man, or a snake oil salesman. Too slick by half.
What do you think he's selling? I think Carroll is a good speaker, a good popularizer, and a nice guy. I feel fortunate to have him representing physics to the public. He is not evangelizing for some particular interpretation and he recognizes that there are alternative interpretations of QM even though he favors MWI.
Also, he's the only scientist who debated William Lane Craig and won by every measure.
Brent
Sean Carroll reminds me more of Alvin Plantinga
who can take math and pull out God.
Carroll makes the big mistake of a number of physics "popularizers" today. He takes the mathematical language of a physical theory (or one version* of that theory, as there are multiple formulations of quantum theory) and pulls a physical ontology out of his math.
That's why it's called an "interpretation". Every physical theory has an ontology that goes with it's mathematics, otherwise you don't know how to apply the mathematics.What is "an ontology"? Seems to me this is a red herring; no way to find evidence that something is real, as opposed to illusionary, unless you apply Vic's claim; it's "real" if it kicks back! Does S's equation kick back? Depends on who you talk to, unlike EM waves. Real or not, S's equation can be used for calculatons. Doesn't matter what its ontological status is. AG
the Schrödinger equation does not directly say what, exactly, the wave function is [Wikipedia: Schrödinger_equation]
On 10/8/2019 12:10 AM, Bruce Kellett wrote:I watched a little of Sean's talk at Google. It is a very slick marketing exercise -- reminded me of a con man, or a snake oil salesman. Too slick by half.
What do you think he's selling?
I think Carroll is a good speaker, a good popularizer, and a nice guy.
I feel fortunate to have him representing physics to the public. He is not evangelizing for some particular interpretation and he recognizes that there are alternative interpretations of QM even though he favors MWI.
Also, he's the only scientist who debated William Lane Craig and won by every measure.
That MWI entails other, unobservable "worlds" is neither a bug or a feature, it's just one answer to the measurement problem. If you have a better answer, feel free to state it.
Brent
On Tuesday, October 8, 2019 at 1:40:33 PM UTC-6, Brent wrote:
On 10/8/2019 11:21 AM, Philip Thrift wrote:
On Tuesday, October 8, 2019 at 12:35:25 PM UTC-5, Brent wrote:
On 10/8/2019 12:10 AM, Bruce Kellett wrote:
On Tue, Oct 8, 2019 at 10:13 AM Lawrence Crowell <goldenfield...@gmail.com> wrote:
On Monday, October 7, 2019 at 4:21:27 PM UTC-5, John Clark wrote:As far as I know dispite lots of talk about it I'm STILL the only one on the list that has actually read Carroll's new book, but he gave an excellent Google talk about it on Friday so maybe his critics will at least watch that; after all even an abbreviated Cliff Notes knowledge of a book is better than no knowledge at all.
John K Clark
I have read Carroll and Sebens' paper on this, which is more rigorous and less qualitative. I honestly do not have a yay or nay opinion on this. It is something to store away in the mental toolbox. Quantum interpretations are to my thinking unprovable theoretically and not falsifiable empirically.
I watched a little of Sean's talk at Google. It is a very slick marketing exercise -- reminded me of a con man, or a snake oil salesman. Too slick by half.
What do you think he's selling? I think Carroll is a good speaker, a good popularizer, and a nice guy. I feel fortunate to have him representing physics to the public. He is not evangelizing for some particular interpretation and he recognizes that there are alternative interpretations of QM even though he favors MWI.
Also, he's the only scientist who debated William Lane Craig and won by every measure.
Brent
Sean Carroll reminds me more of Alvin Plantinga
who can take math and pull out God.
Carroll makes the big mistake of a number of physics "popularizers" today. He takes the mathematical language of a physical theory (or one version* of that theory, as there are multiple formulations of quantum theory) and pulls a physical ontology out of his math.
That's why it's called an "interpretation". Every physical theory has an ontology that goes with it's mathematics, otherwise you don't know how to apply the mathematics.
What is "an ontology"? Seems to me this is a red herring; no way to find evidence that something is real, as opposed to illusionary, unless you apply Vic's claim; it's "real" if it kicks back! Does S's equation kick back? Depends on who you talk to, unlike EM waves. Real or not, S's equation can be used for calculatons. Doesn't matter what its ontological status is. AG
That MWI entails other, unobservable "worlds" is neither a bug or a feature, it's just one answer to the measurement problem. If you have a better answer, feel free to state it.
The math is not the territory.
* The Schrödinger equation is not the only way to study quantum mechanical systems and make predictions. The other formulations of quantum mechanics include matrix mechanics, introduced by Werner Heisenberg, and the path integral formulation, developed chiefly by Richard Feynman. Paul Dirac incorporated matrix mechanics and the Schrödinger equation into a single formulation.
The Schrödinger equation provides a way to calculate the wave function of a system and how it changes dynamically in time. However, the Schrödinger equation does not directly say what, exactly, the wave function is. Interpretations of quantum mechanics address questions such as what the relation is between the wave function, the underlying reality, and the results of experimental measurements.
Did you write that, or are you quoting without attribution? Anyway it's common knowledge on this list.
Brent
--
You received this message because you are subscribed to the Google Groups "Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to everything-li...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/ed9d040a-9853-4e53-9ddc-ad7683aead2f%40googlegroups.com.
It [ontology] matters in applying the theory. In CI you apply the theory by evolving a wf forward in time from an initial state. So the ontology includes a "state" which is some initial wf. But you could do a consistent histories calculation in which the ontology includes and initial and a final state. Or a transactional interpretation in which there is an initial and final measurement result.
Brent
Path-integral methods are already used extensively in computational quantum mechanics CQM) and applied in materials science and other application areas. So we know they are useful.
On Wed, Oct 9, 2019 at 4:35 AM 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:
On 10/8/2019 12:10 AM, Bruce Kellett wrote:I watched a little of Sean's talk at Google. It is a very slick marketing exercise -- reminded me of a con man, or a snake oil salesman. Too slick by half.
What do you think he's selling?
His book? Actually, he is selling a particular approach to QM, and claiming, in no uncertain terms, that his is the only "true" approach.
I take particular exception to his claim that MWI is the SWE and nothing else. He elides the many additional assumptions that he has to make to get correspondence with experience, but derides other approaches for making assumptions! That is just dishonest.
I think Carroll is a good speaker, a good popularizer, and a nice guy.
He is certainly a polished speaker, and is probably a nice guy. But that does not make him right.I feel fortunate to have him representing physics to the public. He is not evangelizing for some particular interpretation and he recognizes that there are alternative interpretations of QM even though he favors MWI.
Maybe so in his book, but that was not apparent in the lecture.
Also, he's the only scientist who debated William Lane Craig and won by every measure.
Bully for him. Debating William Lane Craig is not the height of science......
On 10/8/2019 2:41 PM, Bruce Kellett wrote:
On Wed, Oct 9, 2019 at 4:35 AM 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:
On 10/8/2019 12:10 AM, Bruce Kellett wrote:I watched a little of Sean's talk at Google. It is a very slick marketing exercise -- reminded me of a con man, or a snake oil salesman. Too slick by half.
What do you think he's selling?
His book? Actually, he is selling a particular approach to QM, and claiming, in no uncertain terms, that his is the only "true" approach.
No. He explicitly says (at 14:45) he's going to explain the interpretation he favors but there are others which he discusses in his book.
I take particular exception to his claim that MWI is the SWE and nothing else. He elides the many additional assumptions that he has to make to get correspondence with experience, but derides other approaches for making assumptions! That is just dishonest.
What additional assumptions do you mean?
I think Carroll is a good speaker, a good popularizer, and a nice guy.
He is certainly a polished speaker, and is probably a nice guy. But that does not make him right.I feel fortunate to have him representing physics to the public. He is not evangelizing for some particular interpretation and he recognizes that there are alternative interpretations of QM even though he favors MWI.
Maybe so in his book, but that was not apparent in the lecture.
Also, he's the only scientist who debated William Lane Craig and won by every measure.
Bully for him. Debating William Lane Craig is not the height of science......
No but several scientists have not done well at it, including Vic.
On Tuesday, October 8, 2019 at 2:40:33 PM UTC-5, Brent wrote:
That MWI entails other, unobservable "worlds" is neither a bug or a feature, it's just one answer to the measurement problem. If you have a better answer, feel free to state it.
Brent
MWI, according to Sabine Hossenfelder, is not an answer - in the final analysis - to the measurement problem
The many world interpretation, now, supposedly does away with the problem of the quantum measurement and it does this by just saying there isn’t such a thing as wavefunction collapse. Instead, many worlds people say, every time you make a measurement, the universe splits into several parallel worlds, one for each possible measurement outcome. This universe splitting is also sometimes called branching.
Some people have a problem with the branching because it’s not clear just exactly when or where it should take place, but I do not think this is a serious problem, it’s just a matter of definition. No, the real problem is that after throwing out the measurement postulate, the many worlds interpretation needs another assumption, that brings the measurement problem back.
The reason is this. In the many worlds interpretation, if you set up a detector for a measurement, then the detector will also split into several universes. Therefore, if you just ask “what will the detector measure”, then the answer is “The detector will measure anything that’s possible with probability 1.”
This, of course, is not what we observe. We observe only one measurement outcome.
The many worlds people explain this as follows. Of course you are not supposed to calculate the probability for each branch of the detector. Because when we say detector, we don’t mean all detector branches together. You should only evaluate the probability relative to the detector in one specific branch at a time.
That sounds reasonable. Indeed, it is reasonable. It is just as reasonable as the measurement postulate. In fact, it is logically entirely equivalent to the measurement postulate.
The measurement postulate says: Update probability at measurement to 100%. The detector definition in many worlds says: The “Detector” is by definition only the thing in one branch.
Now evaluate probabilities relative to this, which gives you 100% in each branch. Same thing.
And because it’s the same thing you already know that you cannot derive this detector definition from the Schrödinger equation.
It’s not possible. What the many worlds people are now trying instead is to derive this postulate from rational choice theory. But of course that brings back in macroscopic terms, like actors who make decisions and so on. In other words, this reference to knowledge is equally in conflict with reductionism as is the Copenhagen interpretation.
And that’s why the many worlds interpretation does not solve the measurement problem and therefore it is equally troubled as all other interpretations of quantum mechanics. What’s the trouble with the other interpretations? We will talk about this some other time. So stay tuned.
@philipthrift
--
You received this message because you are subscribed to the Google Groups "Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to everything-li...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/26081e71-1fa3-4294-ac68-a38ef8b6e023%40googlegroups.com.
On Wed, Oct 9, 2019 at 9:53 AM 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:
On 10/8/2019 2:41 PM, Bruce Kellett wrote:
On Wed, Oct 9, 2019 at 4:35 AM 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:
On 10/8/2019 12:10 AM, Bruce Kellett wrote:I watched a little of Sean's talk at Google. It is a very slick marketing exercise -- reminded me of a con man, or a snake oil salesman. Too slick by half.
What do you think he's selling?
His book? Actually, he is selling a particular approach to QM, and claiming, in no uncertain terms, that his is the only "true" approach.
No. He explicitly says (at 14:45) he's going to explain the interpretation he favors but there are others which he discusses in his book.
I was talking about my impression of the lecture, not of his book (which I haven't read).
I take particular exception to his claim that MWI is the SWE and nothing else. He elides the many additional assumptions that he has to make to get correspondence with experience, but derides other approaches for making assumptions! That is just dishonest.
What additional assumptions do you mean?
What assumptions does he have to make to get a probability interpretation? Probability is not an evident property of the SE. Like many approaches to probability in Everett, he has to assume decoherence to distinguishable branches to get anywhere. But that relies on using the Born rule to justify ignoring branches with low amplitude
-- the notorious "trace over environmental degrees of freedom". Sean's "self-locating uncertainty" is not well-defined.
In the lecture he hints that the observer is uncertain about the fate of the cat until he opens the box -- until then he is uncertain of which branch he is on. But given the timescale of decoherence, he has branched within 10^{-20} sec, so the is no longer any "self-locating uncertainty" -- he is definitely on one branch or the other, he just doesn't know which. And that is just classical probability due to lack of knowledge -- nothing quantum about it. In another interview, he does suggest that the "self-locating uncertainty" lasts only until decoherence reaches the observer, at which time copies become entangled within each branch. Now if you can think relevant thoughts in 10^{-20} sec, then his argument might make some sense. But it fails to convince.....
I think Carroll is a good speaker, a good popularizer, and a nice guy.
He is certainly a polished speaker, and is probably a nice guy. But that does not make him right.I feel fortunate to have him representing physics to the public. He is not evangelizing for some particular interpretation and he recognizes that there are alternative interpretations of QM even though he favors MWI.
Maybe so in his book, but that was not apparent in the lecture.
Also, he's the only scientist who debated William Lane Craig and won by every measure.
Bully for him. Debating William Lane Craig is not the height of science......
No but several scientists have not done well at it, including Vic.
That is probably an interest of yours.
I fail to share it, and it is not science.
There will always be people who fail to be convinced by science or by argument, and debating skills are not a prerequisite for good science.
On 10/8/2019 4:21 PM, Bruce Kellett wrote:
On Wed, Oct 9, 2019 at 9:53 AM 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:The low amplitude branches aren't ignored. Do you mean cross-terms in the density matrix?
What additional assumptions do you mean?
What assumptions does he have to make to get a probability interpretation? Probability is not an evident property of the SE. Like many approaches to probability in Everett, he has to assume decoherence to distinguishable branches to get anywhere. But that relies on using the Born rule to justify ignoring branches with low amplitude
-- the notorious "trace over environmental degrees of freedom". Sean's "self-locating uncertainty" is not well-defined.
I tend to agree with you there. But if you assume that the human brain is a classical information processor of limited capacity I think you could get there.
In the lecture he hints that the observer is uncertain about the fate of the cat until he opens the box -- until then he is uncertain of which branch he is on. But given the timescale of decoherence, he has branched within 10^{-20} sec, so the is no longer any "self-locating uncertainty" -- he is definitely on one branch or the other, he just doesn't know which. And that is just classical probability due to lack of knowledge -- nothing quantum about it. In another interview, he does suggest that the "self-locating uncertainty" lasts only until decoherence reaches the observer, at which time copies become entangled within each branch. Now if you can think relevant thoughts in 10^{-20} sec, then his argument might make some sense. But it fails to convince.....
So you're faulting him for not calling 1e-20sec zero?
Seems nit-picky. I see the problem as sloppy introduction of "the observer" harking back to CI.
If observers are quasi-classical (no funny stuff in microtubles) then it should be enough to talk about uncertainty in the location of the geiger counter or the environment, but I understand Sean is trying to explain why, according to Everett, people don't see the superposition.
On 10/8/2019 2:59 PM, Philip Thrift wrote:That sounds reasonable. Indeed, it is reasonable. It is just as reasonable as the measurement postulate. In fact, it is logically entirely equivalent to the measurement postulate.
It's not clear here what "logically" equivalent means. It is instrumentally equivalent...which is why it's an interpretation and not a different theory (as GRW is). It's different from the measurement postulate in that the measurement postulate says the wave function instantaneously changes to match the observed measured value. MWI says those other measured values obtain in other orthogonal subspaces of the Hilbert space and you are only observing one. Those are not "logically" the same.
On Wed, Oct 9, 2019 at 10:49 AM 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:
On 10/8/2019 4:21 PM, Bruce Kellett wrote:
On Wed, Oct 9, 2019 at 9:53 AM 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:The low amplitude branches aren't ignored. Do you mean cross-terms in the density matrix?
What additional assumptions do you mean?
What assumptions does he have to make to get a probability interpretation? Probability is not an evident property of the SE. Like many approaches to probability in Everett, he has to assume decoherence to distinguishable branches to get anywhere. But that relies on using the Born rule to justify ignoring branches with low amplitude
Explain to me how these are functionally different from low amplitude branches.
-- the notorious "trace over environmental degrees of freedom". Sean's "self-locating uncertainty" is not well-defined.
I tend to agree with you there. But if you assume that the human brain is a classical information processor of limited capacity I think you could get there.
Only at the price of re-introducing the human observer into your exposition of QM. I thought that was the cardinal sin of the CI, and here Sean is bringing it back into Everett!!!!
In the lecture he hints that the observer is uncertain about the fate of the cat until he opens the box -- until then he is uncertain of which branch he is on. But given the timescale of decoherence, he has branched within 10^{-20} sec, so the is no longer any "self-locating uncertainty" -- he is definitely on one branch or the other, he just doesn't know which. And that is just classical probability due to lack of knowledge -- nothing quantum about it. In another interview, he does suggest that the "self-locating uncertainty" lasts only until decoherence reaches the observer, at which time copies become entangled within each branch. Now if you can think relevant thoughts in 10^{-20} sec, then his argument might make some sense. But it fails to convince.....
So you're faulting him for not calling 1e-20sec zero?
No. I am not faulting him for not calling it zero. I am faulting him for calling something that is uncertain in any quantum sense for 10^{-20} sec significant for the interpretation of probabilities.
Seems nit-picky. I see the problem as sloppy introduction of "the observer" harking back to CI.
Yes, that is a point I have made.If observers are quasi-classical (no funny stuff in microtubles) then it should be enough to talk about uncertainty in the location of the geiger counter or the environment, but I understand Sean is trying to explain why, according to Everett, people don't see the superposition.
That is achieved by decoherence and the preferred pointer basis. No need to introduce observers and self-locating uncertainty.
Bruce
--
You received this message because you are subscribed to the Google Groups "Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to everything-li...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLS0B%3DUBOUD-erZybbGMG86f%3D_Dd8k6wRYxTKqMpuv%2B-1w%40mail.gmail.com.
On 10/8/2019 5:03 PM, Bruce Kellett wrote:
On Wed, Oct 9, 2019 at 10:49 AM 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:
On 10/8/2019 4:21 PM, Bruce Kellett wrote:
On Wed, Oct 9, 2019 at 9:53 AM 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:The low amplitude branches aren't ignored. Do you mean cross-terms in the density matrix?
What additional assumptions do you mean?
What assumptions does he have to make to get a probability interpretation? Probability is not an evident property of the SE. Like many approaches to probability in Everett, he has to assume decoherence to distinguishable branches to get anywhere. But that relies on using the Born rule to justify ignoring branches with low amplitude
Explain to me how these are functionally different from low amplitude branches.
The branches are projections of the universal Hilbert ray onto (approximately) orthogonal subspaces corresponding to the preferred basis. Cross terms are what make them approximate. The cross-terms supposedly go to zero when you compute the reduced density matrix, but the diagonal terms don't go to zero...they measure the probability of the branches, including branches with low probability.
-- the notorious "trace over environmental degrees of freedom". Sean's "self-locating uncertainty" is not well-defined.
I tend to agree with you there. But if you assume that the human brain is a classical information processor of limited capacity I think you could get there.
Only at the price of re-introducing the human observer into your exposition of QM. I thought that was the cardinal sin of the CI, and here Sean is bringing it back into Everett!!!!
Well, if you're going to explain why we experience a classical world, you're going to have to say something about experience. To say it's information processing in the brain sounds pretty good to me.
But it's relevant to showing MWI is consistent with the experimenter not knowing which "world" he is in. He might not look at the data for a long time.In the lecture he hints that the observer is uncertain about the fate of the cat until he opens the box -- until then he is uncertain of which branch he is on. But given the timescale of decoherence, he has branched within 10^{-20} sec, so the is no longer any "self-locating uncertainty" -- he is definitely on one branch or the other, he just doesn't know which. And that is just classical probability due to lack of knowledge -- nothing quantum about it. In another interview, he does suggest that the "self-locating uncertainty" lasts only until decoherence reaches the observer, at which time copies become entangled within each branch. Now if you can think relevant thoughts in 10^{-20} sec, then his argument might make some sense. But it fails to convince.....
So you're faulting him for not calling 1e-20sec zero?
No. I am not faulting him for not calling it zero. I am faulting him for calling something that is uncertain in any quantum sense for 10^{-20} sec significant for the interpretation of probabilities.
classical probability due to lack of knowledge -- nothing quantum about it
Bruce
Broadly speaking, there are arguably three main concepts of probability:
> I haven't seen yet where MWI serves any useful purpose.
>> What do you think he's selling?His book? Actually, he is selling a particular approach to QM, and claiming, in no uncertain terms, that his is the only "true" approach.
> Other interpretations (but not MWI, as far as I can see) are used in writing programs for computational QM.
@philipthrift
--
You received this message because you are subscribed to the Google Groups "Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to everything-li...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/bafde34d-fa8c-445c-9dd0-be5122a0ea44%40googlegroups.com.
Le jeu. 10 oct. 2019 à 09:34, Philip Thrift <cloud...@gmail.com> a écrit :
On Wednesday, October 9, 2019 at 3:59:50 PM UTC-5, John Clark wrote:On Wed, Oct 9, 2019 at 4:55 PM Philip Thrift <cloud...@gmail.com> wrote:> Other interpretations (but not MWI, as far as I can see) are used in writing programs for computational QM.Like what?John K ClarkMultiple Histories.So there are multiple "worlds", if multiple past histories are real.... so as you dislike MWI, what's different here for you to accept multiple past ? (because if each event has multiple *real* past then likewise it has multiple *real* future).Quentin
--All those moments will be lost in time, like tears in rain. (Roy Batty/Rutger Hauer)
>>> Other interpretations (but not MWI, as far as I can see) are used in writing programs for computational QM.>> Like what?
> Multiple Histories.
On Thu, Oct 10, 2019 at 3:34 AM Philip Thrift <cloud...@gmail.com> wrote:>>> Other interpretations (but not MWI, as far as I can see) are used in writing programs for computational QM.>> Like what?> Multiple Histories.And Multiple Histories uses path integral formulation and path integral formulation uses renormalization theory which is entirely in sympathy with the Shut Up And Calculate Interpretation; it's a wonderful way of getting the right answer, Feynman won a Nobel Prize for inventing it, but he was never entirely comfortable with it because it gave no coherent mental picture. He didn't even try to hide the imperfections in his idea.
>>And Multiple Histories uses path integral formulation and path integral formulation uses renormalization theory which is entirely in sympathy with the Shut Up And Calculate Interpretation; it's a wonderful way of getting the right answer, Feynman won a Nobel Prize for inventing it, but he was never entirely comfortable with it because it gave no coherent mental picture. He didn't even try to hide the imperfections in his idea.> And you have a wonderful many-worlds theory that avoids all infinities? And doesn't need renormalization?
On Thu, Oct 10, 2019 at 6:46 AM Bruce Kellett <bhkel...@gmail.com> wrote:>>And Multiple Histories uses path integral formulation and path integral formulation uses renormalization theory which is entirely in sympathy with the Shut Up And Calculate Interpretation; it's a wonderful way of getting the right answer, Feynman won a Nobel Prize for inventing it, but he was never entirely comfortable with it because it gave no coherent mental picture. He didn't even try to hide the imperfections in his idea.> And you have a wonderful many-worlds theory that avoids all infinities? And doesn't need renormalization?The MWI needs renormalization just like its competitors, but nobody said many-worlds theory is the be all and end all and needs no improvement, but at least it provides a quantum-mechanical model however imperfect it may be.
I think it's a important step toward a theory that is significantly less wrong. I am, of course, not sure of that.
Bottom line: multiple histories are cheaper than many worlds.@philipthrift
--
You received this message because you are subscribed to the Google Groups "Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to everything-li...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/a7ea4da6-e578-4432-b580-d021cde8ae03%40googlegroups.com.
>> The MWI needs renormalization just like its competitors, but nobody said many-worlds theory is the be all and end all and needs no improvement, but at least it provides a quantum-mechanical model however imperfect it may be.> So, in accordance with the logic you used above to be dismissive of path integral methods, MWI is entirely in sympathy with the Shut Up And Calculate Interpretation?
>> I think it's a important step toward a theory that is significantly less wrong. I am, of course, not sure of that.>I'm glad to hear it. Perhaps you could be more tolerant of alternative views?
Le jeu. 10 oct. 2019 à 11:30, Philip Thrift <cloud...@gmail.com> a écrit :
On Thursday, October 10, 2019 at 2:40:53 AM UTC-5, Quentin Anciaux wrote:Le jeu. 10 oct. 2019 à 09:34, Philip Thrift <cloud...@gmail.com> a écrit :
On Wednesday, October 9, 2019 at 3:59:50 PM UTC-5, John Clark wrote:On Wed, Oct 9, 2019 at 4:55 PM Philip Thrift <cloud...@gmail.com> wrote:> Other interpretations (but not MWI, as far as I can see) are used in writing programs for computational QM.Like what?John K ClarkMultiple Histories.So there are multiple "worlds", if multiple past histories are real.... so as you dislike MWI, what's different here for you to accept multiple past ? (because if each event has multiple *real* past then likewise it has multiple *real* future).Quentin--All those moments will be lost in time, like tears in rain. (Roy Batty/Rutger Hauer)That's one way to look at it.In Fay Dowker's debate with a Many Worlder:In this public debate I argue that the path integral (or sum over histories) approach to quantum mechanics provides a One World interpretationI didn't have time to look at it for now (I will), but could you resume her position and explain how considering an event has *multiple* *real* past histories provides a *one* world interpretation ?Thanks;Bottom line: multiple histories are cheaper than many worlds.@philipthrift
And of course nobody but me has bothered to read his book, but everybody has an opinion about it.
>> And of course nobody but me has bothered to read his book, but everybody has an opinion about it.
> You keep posting that, but I've already posted that I have read Carroll's book,
> I don't think QM is the last word,
> so it's not a good idea to draw a lot of far fetched conclusions...like infinitely many universes in which everything happens.
> it leaves open questions like whether the split "propagates" at less than light speed or is instantaneous because it happens in Hilbert space. Carroll cops out by saying either one works...which is what Bohr would have said.
@philipthrift--
You received this message because you are subscribed to the Google Groups "Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to everything-li...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/3ac9a8af-94a0-40aa-908d-c27cfa3cc4bb%40googlegroups.com.
@philipthrift--
You received this message because you are subscribed to the Google Groups "Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to everything-li...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/c082577b-cbb2-4b4b-a557-41ab71e2ac31%40googlegroups.com.
@philipthrift--
You received this message because you are subscribed to the Google Groups "Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to everything-li...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/bafde34d-fa8c-445c-9dd0-be5122a0ea44%40googlegroups.com.
On 14 Oct 2019, at 03:20, spudboy100 via Everything List <everyth...@googlegroups.com> wrote:Sort of like the Boltzmann Brain thing where Bruno suspect is irrelevant. I don't mind irrelevancy, but do like the idea of the BB being, Mr. God Sir!
-----Original Message-----
From: smitra <smi...@zonnet.nl>
To: everything-list <everyth...@googlegroups.com>
Sent: Sun, Oct 13, 2019 11:26 am
Subject: The multiverse almost everyone believes in
Most people believe in either block time or presentism. Few people
believe that the past never really existed. One can, e.g. believe that
God created the universe ten minutes ago which would mean that all our
memories of events that took place earlier are false memories. The
universe came into being ten minutes ago including us with all our false
memories of the events that actually never happened. If we then assume
that the past and the future are/were/will be real (whatever that
means), then that defines a multiverse of Worlds labeled by the time
variable.
Saibal
--
You received this message because you are subscribed to the Google Groups "Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsub...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/059270c5fb2ecd864042bb157214cc57%40zonnet.nl.--
You received this message because you are subscribed to the Google Groups "Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email to everything-li...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/636274581.1877201.1571016044234%40mail.yahoo.com.