Yes my understanding would be the same. Although the brain or computer's 
ability to correctly represent the information about what has happened has 
been destroyed by the reset, the information itself is still embedded in 
the environment. Resetting registers in a computer does not actually 
destroy the information, it merely disperses it into the environment in a 
way that is non-recoverable (by the computer). That's what decoherence is 
all about. So if you wanted to "teleport" yourself across the multiverse in 
such a fashion, you'd have to find a method of really destroying the 
information, which I think is impossible...This theory seems to go back to 
Schrödinger's Cat, before the solution to the paradox was understood.

The quantum eraser does show that some elements of the past can be 
"altered" by quantum measurements, but it's not clear from that that one's 
history on a macroscopic scale is not singularly defined. This is the point 
I'm trying to clarify. In a way I'm not even sure what this means - unless 
the laws of physics are such that it is in principle possible to 
reconstruct the past to an arbitrary level of precision. I think Hawking 
was showing that that isn't the case - at a certain point in very early 
history at least, the information can no longer be resolved, and therefore 
there isn't a single origin point.

On Thursday, August 15, 2013 12:05:42 PM UTC+10, Brent wrote:
> On 8/14/2013 6:41 PM, <javascript:> wrote: 
> >> I guess I don't understand that.   You seem to be considering a simple 
> case of amnesia 
> >> - all purely classical - so I don't see how MWI enters at all.  The 
> probabilities are 
> >> just ignorance uncertainty.  You're still in the same branch of the 
> MWI, you just don't 
> >> remember why your memory was erased (although you may read about it in 
> your diary). 
> > 
> > No, you can't say that you are in the same branch. Just because you are 
> in the clasical 
> > regime doesn't mean that the MWI is irrelevant and we can just pretend 
> that the world is 
> > described by classical physics. It is only that classical physics will 
> give the same 
> > answer as QM when computing probabilities. 
> Including the probability that I'm in the same world as before? 
> > 
> > If what you are aware of is only described by your memory state which 
> can be encoded by 
> > a finite number of bits, then after a memory resetting, the state of 
> your memory and the 
> > environment (which contains also the rest of your brain and body), is of 
> the form: 
> "The rest of my brain"??  Why do you suppose that some part of my brain is 
> involved in my 
> memories and not other parts?  What about a scar or a tattoo.  I don't see 
> that "memory" 
> is separable from the environment.  In fact isn't that exactly what makes 
> memory classical 
> and makes the superposition you write below impossible to achieve? Your 
> brain is a 
> classical computer because it's not isolated from the environment. 
> Brent 
> > 
> > |memory_1>|environment_1> + |memory_2>|environment_2>+... 
> > 
> > where |environment_i> is not (necessarily) normalized. 
> > 
> > It then follows that a process that can lead to the same memory state 
> via different 
> > paths (routine resetting or resetting in case of bad news) will lead to 
> a state |psi>, 
> > such that projecting out a definite memory state gives: 
> > 
> > |memory><memory|psi> = 
> > 
> > |memory> sum over different |environments> 
> > 
> > where the different environments contain different information about the 
> paths that led 
> > to the memory. 
> > 
> > So, from the point of view of a memory state that has undergone a 
> resetting, the 
> > environment will be in a superposition of different states, the reason 
> why the reseting 
> > has been done is thus undetermined prior to a measurement. 
> > 
> > Saibal 
> > 

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