[extropy-chat] Is Many Worlds testable? (was: cold fusion warms up)

scerir scerir at libero.it
Thu Dec 28 23:18:51 UTC 2006

Hi John,

There is something (or much) I do not understand, 
maybe it is too subtle, or maybe it is too late here,
or something else.

> The quantum mind has detectors near each slit
> so it knows which slit the various electrons
> went through.

Ok. (According to the orthodox interpretation
this would produce a smooth distribution pattern
on the plate).

> The quantum mind now signs a document saying that
> it has observed each and every electron and knows
> what slit each electron went through.


> It is very important that the document does not say
> which slit the electrons went through, it only says
> that they went through one slit and one slit only,
> and that the mind has knowledge of which slit.

Ok. But I do not understand why the document cannot
tell the 'welcher weg'. Something about the consciousness?
The consciousness of the quantum mind? The consciousness
of the final observer of the plate?

> After the electrons pass the plate but before
> they hit the photographic film (just place the film
> a long way away to give you time) the mind then uses
> quantum erasure to completely destroy his memory
> of which slit the electrons went through.

Ok. The memory of the quantum mind is erased now.

> The only part remaining is the document.

The only memory is the document.

> Now develop the photographic plate and look at it.
> According to Deutsch if you see interference bands
> then the many world interpretation is correct.

But why the interference pattern would mean that MWI is 
correct? Because here we have interference pattern 
notwithstanding the existence of the document-consciousness?

(I've got the impression that Deutsch thinks that
consciousness causes the collapse. Von Neumann,
the young Heisenberg, Wigner, London, etc.
thought the same. But not Bohr, Born, Dirac, etc.
So at least we can say that Deutsch is not alone!)

(Also I've got the impression that Deutsch thinks
that the knowledge of the 'which way', or the consciousness
of the knowledge of the 'which way', or the possibility
of knowledge of the 'which way' the particle took,
erases the interference pattern. Well, this is not
true. It is not 100% true. It is only partially true. 
So the gedanken experiment above might be too smart 
for the purpose).  

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