On 4/29/2022 5:22 AM, John Clark wrote:

On Thu, Apr 28, 2022 at 4:49 PM Brent Meeker <meekerbr...@gmail.com>wrote:>> Any idea that does not conform with quantum evolution being unitary is an idea that does not conform with experimental evidence and thus has been proven to be incorrect. /> Measurement is, and always has been, described in quantum theory by projection operators...which are not unitary. /That's because an actual measurement is not a probability, it is afact. A *prediction* about what a measurement will be is a probability.

`That seems to be a reply to something because the sentence starts with`

`"That's" but the rest of sentence mentions neither projection operators`

`nor unitarity. It informs the reader that an "actual measurement" is`

`not a probability and instead claims a prediction about a measurement is`

`a probability. This seems doubtful since Kolmogorov says a probability`

`is a number between 0 and 1 and it's a measure on a set of events.`

/> Without them there is nothing in the theory to produce a result that can be compared to empirical observation. /That's why experimental results always outranks any theory, and whyany theory that predicts the Born Rule will not work is a theory thatis dead wrong. It would be nice but a theory doesn't have to have theability to rigorously derive the Born Rule mathematically, but it mustbe compatible with it./> In unitary evolution per the Schroedinger equation there are no "paticular universes", there's only a ray in Hilbert space. Multiple universes is a FAPP viewpoint. But so is wave-function collapse./ Either the wave function collapses or it doesn't.

`And there are either multiple universes or one universe. Schroedinger's`

`equation describes the evolution of one world. I never describes`

`splitting into multiple worlds...except FAPP.`

If it does then collapse then there is no world but this one andSchrodinger's equation is wrong, or at least incomplete, because itsays nothing about the wave collapsing. If it doesn't collapse thenSchrodinger's Equation is fine just as it is and many worlds exist.

It's fine...but there's only one world.

/> The information interpretation is QBism./I think the differences between the Copenhagen Interpretation, QBism,and Shut Up And Calculate are just cosmetic. But if you put lipstickon a pig it's still a pig.

`And it's provided a delicious and nourishing meal for physicists all`

`these years.`

However, if one is completely uninterested in the philosophicalimplications of science and just wants to make new gadgets then youcan be a good productive quantum physicist and have no quantuminterpretation at all.

Nobody can do physics without measurement results. Brent

John K Clark See what's on my new list at Extropolis<https://groups.google.com/g/extropolis>IlIl --You received this message because you are subscribed to the GoogleGroups "Everything List" group.To unsubscribe from this group and stop receiving emails from it, sendan email to everything-list+unsubscr...@googlegroups.com.To view this discussion on the web visithttps://groups.google.com/d/msgid/everything-list/CAJPayv1jXJijbeW8rUT31EPit0bj%3DiswspVnqKpJd%2B2fsg83%3DQ%40mail.gmail.com<https://groups.google.com/d/msgid/everything-list/CAJPayv1jXJijbeW8rUT31EPit0bj%3DiswspVnqKpJd%2B2fsg83%3DQ%40mail.gmail.com?utm_medium=email&utm_source=footer>.

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