🚀 go-pugleaf

In article <1992Sep29.162439.18453@watson.ibm.com>, platt@watson.ibm.com (Daniel E. Platt) writes referring to my article.
> 
> This is not entirely accurate.
> 
(Argument deleted.)

Bell's result depends only on the macroscopic experimental
predictions of QM. You can only escape his result
with a theory that makes different predictions. It does not matter if
the state vector is real or not. It is the predicted macroscopic results
that involve action at a distance. It is strange action at a distance
since you cannot use it to send a signal but is nonetheless action at a
distance.

>... 
> Depends on whose development of QM you read.  In part, the above argument
> implicitly assumes that the state vector must ultimately convey the information
> of what was measured by each observer to the other observers.  Actually,
> the only information it is carrying is what cannot be observed by both
> observers -- even over space-like intervals.

I am assuming nothing about the underlying mathematics of quantum
mechanics. We observe local detections and the angles of a
local polarizer. This tells us something about the probabilities of
combinations of polarizer angles and detections that have occurred at the
remote site. This knowledge or information had to be transmitted
instantaneously.

> What do you mean a wave function (state vector?) 'was there all the time'?
> Here, again, the assumption is made that the state vector must ultimately
> carry the information of what measurement was ultimately made to all observers.
I was simply allowing space for variations on Everett's interpretation. I
would never attempt to defend that or any other interpretation of quantum
mechanics. This is because I think what they are interpreting is false.

>...
> 
> "Preposterous?"  Sounds a tad emotional... the word keeps coming up...

It is intentional and appropriate. The predictions are preposterous
given the lack of experimental or theoretical basis for them.

> One of the elements in this line of argument is that it fails to
> recognize that there is a spectrum of responses that have been
> taken to the assumptions listed above.  Some of them are better
> than others.  I find it a bit surprising given that it was
> acknowledged that physicists don't seem to agree on all the points
> of interpretation.  Particularly, you can have two physicists see
> the same results, say they agree on what the results were, and then
> disagree on whether it means the photon state vectors collapsed.

Almost all physicists agree about the experimental predictions. It is
these predictions, not the underling model, that is the problem.

> |> 
> |> I suggest two answers. This first is best understood through
> |> the Hans Christian Anderson fairy tale *The Emperor's New Clothes*.
> 
> This would be fair if everyone agreed, and nobody argued.  As it stands,
> most people argue, and not everyone agrees.  Consensus has not been
> achieved -- for what ever reasons.  This implies that most people are
> aware of the problem with the clothes; however, most people have 
> acquired some degree of comfort or acceptance of the situation.

Most physicists seem to have reached a consensus against Einsteins position
regarding objective reality. If this were not true, tests of Bell's
inequality would be a much higher priority. Of course they do not agree
on what to replace objective reality with. That is because none of the
alternatives make any sense. None of them can be defined with
mathematical rigor.

> ... Unfortunately for it, the
> |> non preposterous (local Lorentz invariant collapse) version of quantum
> |> mechanics is an explicitly incomplete theory. It implies that the wave
> |> function has an objective physical reality.
> 
> Does it?  That's one interpretation... not one that's universally held.

If the wave function has an experimentally observable, through tests of
Bell's inequality, local structure this would be compelling evidence
for its objective reality.

>... 
> Wouldn't they? I expect there are quite a few who accept objective reality.
>...

I mean objective reality in the sense that Einstein used the term. The
current formulation of quantum mechanics is an incomplete description
of an underlying objective reality. I do not think all physicists reject
Einsteins approach. Most seem to. 

> ...
> I suspect that this is the reason the question has 
> persisted so long without the emergence of some consensus -- it isn't easily
> measured; most of the time it is irrelevant; it is likely not going to change
> the utility of the results of QM as currently developed.

I do not expect anything to overturn the usefulness of existing results.
If quantum collapse is a physical measurable process, than understanding
its structure is likely to be of enormous theoretical and practical
importance. Bell's results provide an initial experimental window
on this structure. Who knows what physicists will find once they
start looking. No one at the birth of quantum mechanics would have
suspected it would lead in a few decades to powerful inexpensive computers.

Paul Budnik