The Incessant Arguments about MWI

[John Clark]

On Mon, Nov 18, 2024 at 5:37 PM Brent Meeker <meeke...@gmail.com> wrote:

> MWI needs to explain how and when the worlds split,

As I've said many many times before, the world splits whenever there is a change that produces a difference between the two worlds, conscious human observers are capable of producing such a change that makes the universe split, but so can dead human cadavers which are presumably non-conscious non-observers. In Many Worlds, anything and everything that is not forbidden to exist by the laws of physics is required to exist; in other words, the laws of physics work the same way for EVERYTHING.   

>> The useful role that Many Worlds provides is that it doesn't need to explain what a "measurement" or an "observer" is

> LOL.  You just wrote three paragraphs immediately above each of which referred to "observed".

If you ask me what would an observer expect to see in a certain situation, then for me to answer your question I'm going to have to use the word "observer". I'm not afraid of that word because Many Worlds does not say observers don't exist, instead it says it doesn't care what an "observer" is or whether such a thing exists or not because the laws of physics always treat everything the same way.

A particle X has a Half-life of 60 seconds and Y (which could be you or it could be anything else) interacts with X once a second, thus after one second the probability of Y being in the same universe as the one where the atom decayed is 50%, and after 30 seconds the probability (using the formula P(decay by time t) = 1 - e^(-λt) ,where λ is ln2/60 minutes) of Y being in the same universe as the one where the atom decayed is about 29%, and after 10 minutes the probability is about 11%. 

As you can see, the more often Y interacts with particle X the more likely it is that Y and undecayed particle X will still be in the same universe, although if Y is a conscious human observer he would probably use different words to describe the experience, such as "the more closely I watch the atom the less likely it is to decay". 

We know for certain, thanks to experiment, that this Quantum Zeno Effect exists, and Many Worlds has no trouble clearly explaining how that could happen, if Copenhagen wants to explain how this could occur they're going to need to crank up their bafflegab knob to 11.  

>>nor does it need to explain exactly, or even approximately, where the Heisenberg cut is.

> No, it just assumes there is a point at which the world becomes multiple and measurement is complete.

Many Worlds needs no such assumption, in fact it doesn't even make any sense; in Many Worlds you can always replace the word "measurement" with "change" or "interaction", and changes and interactions are never complete.  Copenhagen is the one that needs to make that assumption, and the theory that needs the fewest assumptions is the best theory. 

John K Clark    See what's on my new list at  Extropolis

bgn

[Brent Meeker]

You skipped the "how" part.  If a particle interacts so that it's state changes to A with probabilty 0.99 and B with probability 0.01 is that a change that produces a difference between two worlds?

Brent

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[Alan Grayson]

On Tuesday, November 19, 2024 at 9:29:13 PM UTC-7 Brent Meeker wrote:

You skipped the "how" part.  If a particle interacts so that it's state changes to A with probabilty 0.99 and B with probability 0.01 is that a change that produces a difference between two worlds?

Brent

CMIIAW, but isn't the MWI supposed to solve the measurement problem? But AFAICT, it fails to accomplish its mission. E.g., before Everett, if someone did a quantum experiment, they'd get some result, but couldn't predict exactly what it would be. After Everett. the exact same situation exists, in this world. That is, they'd get some result and couldn't predict exactly what it would be! Moreover, there seems to be a psychological relationship, or kinship, between the advocate of the MWI, and Trumpism; namely, no matter how many examples of the huge complications created by the MWI, its advocates are never shaken in their beliefs, not in the slightest. AG

[Alan Grayson]

On Tuesday, November 19, 2024 at 11:56:18 PM UTC-7 Alan Grayson wrote:

On Tuesday, November 19, 2024 at 9:29:13 PM UTC-7 Brent Meeker wrote:

You skipped the "how" part.  If a particle interacts so that it's state changes to A with probabilty 0.99 and B with probability 0.01 is that a change that produces a difference between two worlds?

Brent

CMIIAW, but isn't the MWI supposed to solve the measurement problem? But AFAICT, it fails to accomplish its mission. E.g., before Everett, if someone did a quantum experiment, they'd get some result, but couldn't predict exactly what it would be. After Everett. the exact same situation exists, in this world. That is, they'd get some result and couldn't predict exactly what it would be! Moreover, there seems to be a psychological relationship, or kinship, between the advocate of the MWI, and Trumpism; namely, no matter how many examples of the huge complications created by the MWI, its advocates are never shaken in their beliefs, not in the slightest. AG

Another complication of the MWI concerns the numerous worlds created by ants, flying insects, and microscopic entities, as they go about their lives, zigging and zagging, and creating a multitude of worlds in the process (according to the MWI). So, do we humans have copies of ourselves in these worlds, or are we somehow cut off, with the results that these worlds must be partial worlds?  Given all these issues with the MWI, I definitely prefer the much simpler view that the wf evolves into a delta function centered on the measurement which is realized -- which is an excellent description of what apparently happens -- while the underlying process which produces this result remains unknown. Better a TBD than foolishness. AG

[John Clark]

On Tue, Nov 19, 2024 at 11:29 PM Brent Meeker <meeke...@gmail.com> wrote:

> You skipped the "how" part.  If a particle interacts so that it's state changes to A with probabilty 0.99 and B with probability 0.01 is that a change that produces a difference between two worlds?

Yes. And you're asking exactly the same question that you asked and I already answered in some detail in the thread called "Branch counting (was: Spin Superposition)".

[John Clark]

On Wed, Nov 20, 2024 at 1:56 AM Alan Grayson <agrays...@gmail.com> wrote:

 > before Everett, if someone did a quantum experiment, they'd get some result, but couldn't predict exactly what it would be.

True. If you're only interested in predicting what reading you're going to get on your voltmeter then Shut Up And Calculate works just fine. But if you want to know why we need to resort to probabilities at all when Schrodinger's equation is 100% deterministic then Many Worlds can explain why that is, and so can Objective Collapse and Pilot Wave, although they require more assumptions than Many Worlds. 

By contrast if you ask somebody who insists but the quantum wave function is not "real " why do we need to resort to probabilities at all when Schrodinger's equation is 100% deterministic they could not embrace any of the above quantum interpretations so the only answer they could give you is "Shut Up And Calculate". 

> CMIIAW

IHA

there seems to be a psychological relationship, or kinship, between the advocate of the MWI, and Trumpism;

 

Wow, calling a guy known for disliking Trump a Trump supporter, what a witty and original insult!  I've never heard that one before, except for the 19 dozen times I've heard it from you. 

John K Clark    See what's on my new list at  Extropolis

. 

[Alan Grayson]

On Wednesday, November 20, 2024 at 5:45:04 AM UTC-7 John Clark wrote:

On Wed, Nov 20, 2024 at 1:56 AM Alan Grayson <agrays...@gmail.com> wrote:

 > before Everett, if someone did a quantum experiment, they'd get some result, but couldn't predict exactly what it would be.

True. If you're only interested in predicting what reading you're going to get on your voltmeter then Shut Up And Calculate works just fine. But if you want to know why we need to resort to probabilities at all when Schrodinger's equation is 100% deterministic then Many Worlds can explain why that is, and so can Objective Collapse and Pilot Wave, although they require more assumptions than Many Worlds. 

By contrast if you ask somebody who insists but the quantum wave function is not "real " why do we need to resort to probabilities at all when Schrodinger's equation is 100% deterministic they could not embrace any of the above quantum interpretations so the only answer they could give you is "Shut Up And Calculate". 

> CMIIAW

IHA

there seems to be a psychological relationship, or kinship, between the advocate of the MWI, and Trumpism;

 

Wow, calling a guy known for disliking Trump a Trump supporter, what a witty and original insult!  I've never heard that one before, except for the 19 dozen times I've heard it from you. 

Trump has a multitude of flaws, but his supporters studiously ignore them. Same with you and the MWI. Moreover, you use "shut up and calculate" as a caricature of Copenhagen. I prefer to acknowledge there is presently no solution to the measurement problem than to blindly accept a theory which utterly fails the smell test. AG