On 8/21/2013 3:57 AM, Quentin Anciaux wrote:

2013/8/21 meekerdb <meeke...@verizon.net <mailto:meeke...@verizon.net>>

    On 8/20/2013 5:26 AM, smi...@zonnet.nl <mailto:smi...@zonnet.nl> wrote:

        Citeren meekerdb <meeke...@verizon.net <mailto:meeke...@verizon.net>>:

            On 8/16/2013 4:57 PM, smi...@zonnet.nl <mailto:smi...@zonnet.nl> 

                Citeren meekerdb <meeke...@verizon.net 

                    On 8/15/2013 6:18 AM, smi...@zonnet.nl 
<mailto:smi...@zonnet.nl> wrote:

                        Citeren meekerdb <meeke...@verizon.net

                            On 8/14/2013 6:41 PM, smi...@zonnet.nl
                            <mailto:smi...@zonnet.nl> wrote:

                                    I guess I don't understand that.   You seem 
to be
                                    considering a simple case of amnesia - all 
                                    classical - so I don't see how MWI enters 
at all.
                                     The probabilities are just ignorance 
                                     You're still in the same branch of the 
MWI, you
                                    just don't remember why your memory was 
                                    (although you may read about it in your 

                                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?

                        With classical I mean a single world theory where you 
                        compute the probabilities based "ignorance". This 
yields the
                        same answer as assuming the MWI and then comouting the
                        probabilities of the various outcomes.

                                If what you are aware of is only described by 
                                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 
                            what makes memory classical and makes the 
superposition you
                            write below impossible to achieve? Your brain is a 
                            computer because it's not isolated from the 

                        What matter is that the state is of the form:

                        |memory_1>|environment_1> + |memory_2>|environment_2>+..

                        with the |memory_j> orthonormal and the |environment_j>
                        orthogonal. Such a completely correlated state will 
arise due to
                        decoherence, the probabilities which are the squared 
norms of
                        the |environment_j>'s are the probabilities. They 
behave in a
                        purely classical way due this decomposition.

                        The brain is never isolated from the environment; if 
                        onto an |environment_j> you always get a definite 
                        memory state, never a supperposition of different 
                        But it's not the case that projecting onto a ddefinite 
                        state will always yield a definite classical 
environment state
                        (this is at the heart of the  Wigner's friend thought 

                    I think Wigner's friend has been overtaken by decoherence. 
While I
                    agree with what you say above, I disagree that the 
                    are macroscopically different.  I think you are making 
                    assumptions: that "memory" is something that can be "reset" 
                    "resetting" its physical environment and yet still holding 
                    memory is classical.

                The |environment_i> have to be different as they are entangled 
                different memory states, precisely due to rapid decoherence. The
                environment always "knows" exactly what happened. So, the 
assumption is
                not that the environment "doesn't know" what has been done 
                implies that the environment does know), rather that the the 
                whose memory is reset doesn't know why the memory was reset.

                So, if you have made a copy of the memory, the system files 
etc., there
                is no problem to reboot the system later based on these copies. 
                that the computer is running an artificially intelligent system 
in a
                virtual environment, but such that this virtual environment is 
                based on real world data. This is actually quite similar to how 
                brain works, what you experience is a virtual world that the 
                creates, input from your senses is used to update this model, 
but in the
                end it's the model of reality that you experience (which leaves 
quite a
                lot of room for magicians to fool you).

                Then immediately after rebooting, you won't yet have any 
                that is in the environment about why you decided to reboot. You 
                have macroscopically different environments where the reason for
                rebooting is different but where you are identical.

            But that's where I disagree - not about the conclusion, but about 
            possibility of the premise.  I don't think it's possible to erase, 
in the
            quantum sense, just your memory.  Of course you can given a drug 
that erases
            short term memory and so it may be possible to create a drug that 
            long term memory too, i.e. induces amnesia.  But what you require 
is to
            erase long term memory in a quantum sense so that all the 
            entanglements with the environment are erased too.  So I don't 
think you can
            be to the "erased memory" state you  need.


        But then, there is no problem restoring the original configuration of a 
PC (e.g.
        if it has been infected by a virus, the systme may have become 
        and you need to format the hard drive and install the OS). If the 
computer where
        running an AI then that AI would simply be "born again".

        If the state of the mulitverse were such that there are two sectors 
were this
        happened with two different virusses the culprit of having to reset the 
PC, then
        from the point of view of the "born again AI", which virus caused the 
problem is
        not deternoned until it accesses that information.

        The born again AI is a unique state that isn't different in any of the 
        possible histories, if not then you would still have traces of the 
virus left
        behind in the system.

    Why should it matter that it was running an AI instead of some other 
program?  You
    seem to be saying that any reset will produce uncertainty, because there is 
    other branch of the multiverse in which there was a reset for a different 
reason.  I
    can only understand that in the context of the program as a Platonic entity 
- so for
    that entity, which world it is in is uncertain.  Is that what you're saying?


ISTM that it is the same as FPI, to correctly predict your future after the reset, you have to take in account all the branches where you are in the same memory state, those branches may have different past (and of course future), hence both side after the reset are uncertain... it's not that you can jump on one branch or another, it means you are in all the branches that are consistent with your memory state...

But it seems to me that this reset is a magical, impossible operation. If the human brain is a classical computer then that means it's computational state can be reset. But it also means the its physical state can't be reset. The resetting operation itself, being a classical operation, is irreversible because of decoherence into the environment. So the environment has the information about the state leading up to the reset and the reset operation. So when you say 'you' can find yourself on another branch, it's not clear what 'you' refers to. Apparently it would have to refer to an abstract computation (per Bruno, I guess) that happened to go through the same state twice (due to the 'reset') in this world AND also at least once in some other world. But if it went through that state in some other world, there was already FPI even without the reset. Right?


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