[ExI] R: Re: Cramer on impossibility of FTL communication

[Adrian Tymes]

On Sep 2, 2015 11:07 AM, "scerir at alice.it" <scerir at alice.it> wrote:
> If you have a source of entangled photons and this source is much much
closer
> to
>  location A than to location B, and if A and B are close enough, an
observer O
> could jump from A to B and you can imagine he could perform magic tricks.

No I can't.  (Not any he could not already perform, anyway.)  He knows what
the photons at B will be before anyone who was previously there has
directly measured them.  So what?  It is known he hopped from A and could
have picked up the information there.

Also, his hops are limited to light speed.

> In other words ... in general the problem arises because obsevers are
>  local, and quantum correlations are not. But if you have ... nonlocal
>  observers ....

...which you don't.

> No story in space-time can describe nonlocal correlations: we have no tool
>  in our story-toolbox to talk about nonlocal correlations (Gisin). Hence,
>  we usually say things like "event A influences event B", or
> "event A has a spooky action at a distance on event B" or
>  "event A causes a collapse of the wavefunction at location B".
>  But we know that this is all wrong: there is no time ordering between the
>  events A and B ("acausality").

More to the point, A and B are both caused by Z.

Event A does nothing at location B, period.

Event A causes people at A to know something about B by logical inference.
This itself does not actually do anything at B.  The knowledge about what
is at B can not reach B at faster than light.

This applies to nonquantum things too.  Let us say you have a bag of 15
apples.  I take some number and leave.  Some time later, you count and find
you have 10 apples.  You thus know I took 5, but does that measurement
actually cause anything at my location to happen?  It does not.  I had
taken 5 apples all along; that you have measured this does not now cause
that fact to spring into being, but only to become known to you.
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