[Fwd: NDPR David Shoemaker, Personal Identity and Ethics: A Brief Introduction]

[ronaldheld]

Stathis
  This was mentioned in the TNG technical manual. I do not recall,
right, now, which post TOS episodes mentioned it.
                                                  Ronald

On Mar 2, 8:42 am, Stathis Papaioannou <stath...@...> wrote:

> 2009/3/2 ronaldheld <RonaldH...@...>:
>
>
>
> > Maybe the terminology does not fit here, to make a copy of my brain,
> > wouldn't you need more than memories, but the state of the brain at
> > one time to "quantum resolution" (TNG transporter term).
>
> The question is what level of resolution is needed in order to copy
> the memories, personality etc. You may not need quantum resolution,
> since in that case it is hard to see how you could avoid drastic
> mental state changes while just sitting still. Also, in which TNG
> episode does it mention quantum resolution for the transporter?
>
> --
> Stathis Papaioannou

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[Bruno Marchal]

On 03 Mar 2009, at 13:40, Stathis Papaioannou wrote:

>
> 2009/3/3 Bruno Marchal <marchal@...>:
>
>> I think that comp practitioners will divide, in the long run,  along
>> three classes:
>>
>> A:  majority. Accept teleportation but disallow overlap of
>> "individuals": annihilation first, reconstitution after. No right to
>> self-infliction. In case of accidental or exceptional self-
>> multiplication, consent is asked at any time.
>> B: a stable minority (in the long run). Accept teleportation but do
>> allow overlap of individuals. Some will fight for the right of self-
>> infliction including the consent made before the duplication, but  
>> with
>> precise protocol. You know the problem of the masochist: I say no,
>> continue, I say "no no", stop!
>> C:  the bandits. They violates protocols and don't ask for consents.
>> They should normally be wanted, I mean researched by all the polices
>> of the universe, or already be in jail or in asylum.
>
> I think B might work, since it is more or less like the present
> situation, where our decisions are based on a rough risk-benefit
> analysis, i.e. we decide on a course of action if as a result
> gain*Pr(gain) >= loss*Pr(loss). So we decide to smoke, for example, if
> we judge the pleasure of smoking (or the suffering caused by trying to
> give it up) to outweigh the suffering that may result from
> smoking-related illnesses. However, there are also differences if the
> copies are allowed to overlap. If I make a decision that has an
> adverse effect on my future self I may regret the decision, but it's
> not possible to ask my past self to reverse it. On the other hand, if
> I agree for one of my copies to torture the other it is always
> possible for the victim to ask the torturer to release him. Also, it
> is possible for the torturer to come to believe that he is never at
> risk himself after repeated duplications: I've done this many times
> and it's always the *other* guy who suffers, not me, so there is no
> reason for me not to repeat the process. This would be so even if the
> agreement was for 100 copies to be made and 99 of them enslaved: the
> one who does the enslaving may come to believe that he is never at
> risk, and continue creating copies 100 at a time.

You can then imagine the surprise of the copy or copies:  "- I did  
this often and thought there are no risk, but here I am enslaved, and  
I will suffer and die".

That is why the B people made a law, for helping those who  
misunderstand the probability. If you decide (before duplication) to  
kill the copy, the choice of victim/torturer is still decided through  
a throw of a fair coin. This makes the decision unbiased by fake  
protocols based on a bad understanding of what the comp probabilities  
are.

Iterating the procedure, with the throwing of the coin, could make you  
believe you are incredibly lucky, but the computationalist should know  
better: this is just the "usual" comp-suicide self-selection (assuming  
of course we can really kill the copies, which is in itself not an  
obvious proposition).

Bruno


http://iridia.ulb.ac.be/~marchal/




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[Günther Greindl]

Hi,

> better: this is just the "usual" comp-suicide self-selection (assuming  
> of course we can really kill the copies, which is in itself not an  
> obvious proposition).


I have been thinking along these lines lately, in a somewhat different
context: the teleportation with annihilation experiment together with
the no cul de sac conjecture and RSSA (that is, a case not covered by
Jack's paper).

Imagine the sequence:

Scan - Annihilate - Signal - Reconstitute

Now consider that the Signal travels for 100 000 lightyears
before it hits the reconstitution chamber (just to
have a big distance, the concern is causal disconnection in spacetime).

Now, in the meantime, the reconstitution chamber has been overtaken by
aliens (coming from the other side of the galaxy) who have advanced
technology and can control the multiverse - they decide the tweak the
multiverse that the reconstitution happens in _no_ multiverse at all (by
destroying all chambers).

This would suggest that the no cul de sac conjecture implies that
annihilation in the above sequence fails.

But surely this can not depend on the decision of the aliens, who were
nowhere near the causal lightcone of the annihilation event.

This would imply one of three things (in my view in decreasing degree of
plausibility):

.) no cul-de-sac is false; no QI, even in RSSA scenarios.
.) annihilation always fails. That is, if a copying machine exists,
there will always be a version of you which feels that copying has not
succeeded and "nothing happened" (even if you said you wanted to be
annihilated after the duplication).
.) COMP obeys global super-selection rules, akin to pre-determinism;
that is, in scenarios where aliens destroy the chambers, annihilation
fails, else not. Analogously for other scenarios.


Cheers,
Günther


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[Stathis Papaioannou-2]

2009/3/4 Bruno Marchal <marchal@...>:

> That is why the B people made a law, for helping those who
> misunderstand the probability. If you decide (before duplication) to
> kill the copy, the choice of victim/torturer is still decided through
> a throw of a fair coin. This makes the decision unbiased by fake
> protocols based on a bad understanding of what the comp probabilities
> are.

Yes, deciding which copy will take on which role by a coin toss would
probably eliminate dynasties of torturers. This is an interesting
point, since the fact that the coin toss is introduced does not
actually do anything ta change the probability that you will end up
being tortured, its effect being mainly psychological.


--
Stathis Papaioannou

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[Stathis Papaioannou-2]

2009/3/4 Günther Greindl <guenther.greindl@...>:

> Imagine the sequence:
>
> Scan - Annihilate - Signal - Reconstitute
>
> Now consider that the Signal travels for 100 000 lightyears
> before it hits the reconstitution chamber (just to
> have a big distance, the concern is causal disconnection in spacetime).
>
> Now, in the meantime, the reconstitution chamber has been overtaken by
> aliens (coming from the other side of the galaxy) who have advanced
> technology and can control the multiverse - they decide the tweak the
> multiverse that the reconstitution happens in _no_ multiverse at all (by
> destroying all chambers).
>
> This would suggest that the no cul de sac conjecture implies that
> annihilation in the above sequence fails.
>
> But surely this can not depend on the decision of the aliens, who were
> nowhere near the causal lightcone of the annihilation event.
>
> This would imply one of three things (in my view in decreasing degree of
> plausibility):
>
> .) no cul-de-sac is false; no QI, even in RSSA scenarios.
> .) annihilation always fails. That is, if a copying machine exists,
> there will always be a version of you which feels that copying has not
> succeeded and "nothing happened" (even if you said you wanted to be
> annihilated after the duplication).
> .) COMP obeys global super-selection rules, akin to pre-determinism;
> that is, in scenarios where aliens destroy the chambers, annihilation
> fails, else not. Analogously for other scenarios.

The no-cul-de-sac hypothesis is false if you allow that there is some
means of destroying all copies in the multiverse. But there is
probably no such means, no matter how advanced the aliens.


--
Stathis Papaioannou

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[Bruno Marchal]

On 04 Mar 2009, at 07:13, Stathis Papaioannou wrote:

>
> 2009/3/4 Günther Greindl <guenther.greindl@...>:
>
>> Imagine the sequence:
>>
>> Scan - Annihilate - Signal - Reconstitute
>>
>> Now consider that the Signal travels for 100 000 lightyears
>> before it hits the reconstitution chamber (just to
>> have a big distance, the concern is causal disconnection in  
>> spacetime).
>>
>> Now, in the meantime, the reconstitution chamber has been overtaken  
>> by
>> aliens (coming from the other side of the galaxy) who have advanced
>> technology and can control the multiverse - they decide the tweak the
>> multiverse that the reconstitution happens in _no_ multiverse at  
>> all (by
>> destroying all chambers).
>>
>> This would suggest that the no cul de sac conjecture implies that
>> annihilation in the above sequence fails.
>>
>> But surely this can not depend on the decision of the aliens, who  
>> were
>> nowhere near the causal lightcone of the annihilation event.
>>
>> This would imply one of three things (in my view in decreasing  
>> degree of
>> plausibility):
>>
>> .) no cul-de-sac is false; no QI, even in RSSA scenarios.
>> .) annihilation always fails. That is, if a copying machine exists,
>> there will always be a version of you which feels that copying has  
>> not
>> succeeded and "nothing happened" (even if you said you wanted to be
>> annihilated after the duplication).
>> .) COMP obeys global super-selection rules, akin to pre-determinism;
>> that is, in scenarios where aliens destroy the chambers, annihilation
>> fails, else not. Analogously for other scenarios.
>
> The no-cul-de-sac hypothesis is false if you allow that there is some
> means of destroying all copies in the multiverse. But there is
> probably no such means, no matter how advanced the aliens.

Indeed, that would be like if a number could make disappear another  
number. Even a God cannot do that!

Bruno


http://iridia.ulb.ac.be/~marchal/




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[Bruno Marchal]

On 04 Mar 2009, at 07:08, Stathis Papaioannou wrote:

>
> 2009/3/4 Bruno Marchal <marchal@...>:
>
>> That is why the B people made a law, for helping those who
>> misunderstand the probability. If you decide (before duplication) to
>> kill the copy, the choice of victim/torturer is still decided through
>> a throw of a fair coin. This makes the decision unbiased by fake
>> protocols based on a bad understanding of what the comp probabilities
>> are.
>
> Yes, deciding which copy will take on which role by a coin toss would
> probably eliminate dynasties of torturers. This is an interesting
> point, since the fact that the coin toss is introduced does not
> actually do anything ta change the probability that you will end up
> being tortured, its effect being mainly psychological.

Absolutely so.
That is why, fundamentally, the B people illustrate a higher moral  
ethic. By allowing overlap, and delayed self-annihalation, they force  
the teleporter user to have a better idea of what he is going to do,  
even if they know they cannot have a complete knowledge or any  
certainties of what will happen. The A people, who disallow overlaps  
between copies and original, are more like: "let us use the comp  
theory without trying to think about what we are really doing". It is  
a bit the difference between those who say "yes" to the doctor after  
many explanations, and those who say "yes" to the doctor, but doesn't  
want to know what the doctor will precisely do. Of course I respect  
the two attitudes. I disrespect only the C people, who doesn't care  
about any person they feel different. The A people are ignorant, but  
does not ignore their ignorance. The C people are ignorant and ignore  
their ignorance. The B people, note, are ignorant, but try to be less  
ignorant.

Bruno

http://iridia.ulb.ac.be/~marchal/




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[Johnathan Corgan]

On Wed, 2009-03-04 at 12:25 +0100, Bruno Marchal wrote:

> > The no-cul-de-sac hypothesis is false if you allow that there is some
> > means of destroying all copies in the multiverse. But there is
> > probably no such means, no matter how advanced the aliens.
>
> Indeed, that would be like if a number could make disappear another  
> number. Even a God cannot do that!

We are a collection of particles, though the exact arrangement and
constitution of such is constantly changing.  Yet, under most
circumstances, from moment to moment our instantaneous state follows a
trajectory such that this state continues to be a member of the larger
class that is "me, being conscious".  

It is again the situation of many microstates mapping to one higher
level, emergent macrostate according to some membership function, the
exact nature of which depends on your specific theory of identity.

The no cul-de-sac conjecture, more precisely, states that as the
wavefunction of our present collection of particles unitarily evolves
there will always be at least one decoherent branch of it that continues
to satisfy the macrostate membership function that is "me, being
conscious", delays and copies notwithstanding.

It is at least conceivable that the collection of particles that is me
could undergo some environmental interaction such that *all* the
following entangled branches decohere into states that do *not* map to
the emergent class of "me, being conscious."  Then I would be dead.

There are many questions/assumptions in the above line of reasoning.
What is the "macrostate membership function" that defines a set of
particles as me? As the set becomes entangled with its environment, how
and when does one decoherent branch then decohere into one or more new
branches (that are still me)? Presumably, our "digital level of
substitution" is much higher than the exact quantum state of this
collection of particles.  What microstate changes don't make a
difference, which do?

Johnathan Corgan



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[Günther Greindl]

Stathis,

Stathis Papaioannou wrote:
>> Imagine the sequence:
>>
>> Scan - Annihilate - Signal - Reconstitute

> The no-cul-de-sac hypothesis is false if you allow that there is some
> means of destroying all copies in the multiverse. But there is
> probably no such means, no matter how advanced the aliens.

Assuming COMP you are probably right, but with standard MWI I'm with
Jonathan - it suffices that the aliens would make sure that no
decoherent branch contains a successor macrostate; considering that the
reconstitution machine and the incoming beam are (localized)
macrostates, this seems plausible. Maybe we would have to modify the
scenario a bit (not 100 000 lightyears distance, which would open up
possibilites for very different histories) but the minimal distance to
ensure that annihilation has finished before reconstitution "would"
begin (without tampering).

Cheers,
Günther

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[Günther Greindl]

Bruno,

> Indeed, that would be like if a number could make disappear another  
> number. Even a God cannot do that!

The idea would be rather that some continuations would correspond
to non-existent numbers, like, say, the natural number between 3 and 4.

Cheers,
Günther



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[Stathis Papaioannou-2]

2009/3/5 Johnathan Corgan <jcorgan@...>:

> It is at least conceivable that the collection of particles that is me
> could undergo some environmental interaction such that *all* the
> following entangled branches decohere into states that do *not* map to
> the emergent class of "me, being conscious."  Then I would be dead.

It seems possible, but in that case the QTI would be wrong. Also, it
isn't clear that the MWI says that everything that can happen, does
happen, even though that is how it is sometimes characterised.


--
Stathis Papaioannou

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[Bruno Marchal]

Hi Günther,

On 05 Mar 2009, at 00:50, Günther Greindl wrote:

>
> Bruno,
>
>> Indeed, that would be like if a number could make disappear another
>> number. Even a God cannot do that!
>
> The idea would be rather that some continuations would correspond
> to non-existent numbers, like, say, the natural number between 3 and  
> 4.

I am not sure I understand. If the continuation uses non existent  
numbers, the continuation does not exist, or it is an inconsistent  
continuation, that is a cul-de-sac world. I can prove that 0 = 1, if  
there is a natural number between 3 and 4.
A god cannot make disappear a natural number, nor introduce a natural  
number where there is none. It seems to me.

Best,

Bruno

http://iridia.ulb.ac.be/~marchal/




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[Günther Greindl]

HI Bruno,

>>> Indeed, that would be like if a number could make disappear another
>>> number. Even a God cannot do that!
>> The idea would be rather that some continuations would correspond
>> to non-existent numbers, like, say, the natural number between 3 and  
>> 4.
>
> I am not sure I understand. If the continuation uses non existent  
> numbers, the continuation does not exist, or it is an inconsistent  
> continuation, that is a cul-de-sac world. I can prove that 0 = 1, if  
> there is a natural number between 3 and 4.
> A god cannot make disappear a natural number, nor introduce a natural  
> number where there is none. It seems to me.

We are just talking a little past each other. To recap:

I initially meant that it would be possible, in a teleportation
experiment, that aliens prevent any copies from being instantiated.

You then said that that would be equivalent to making disappear a
number, which is not possible.

My idea was rather that the instantiations would not correspond to
numbers in the first place - that is why the aliens could destroy the
machine (it follows from 3-det that something _had_ to happen to prevent
successor states which wouldn't correspond to numbers).

So, of course nobody can introduce new numbers - but if there were
successor states which would require new numbers, that would mean that
QI is false - there a cul de sacs (modus tollens).

Best Wishes,
Günther

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[Günther Greindl]

Hi Stathis,

>> It is at least conceivable that the collection of particles that is me
>> could undergo some environmental interaction such that *all* the
>> following entangled branches decohere into states that do *not* map to
>> the emergent class of "me, being conscious."  Then I would be dead.
>
> It seems possible, but in that case the QTI would be wrong. Also, it
> isn't clear that the MWI says that everything that can happen, does
> happen, even though that is how it is sometimes characterised.

Indeed, that is what Jonathan (I guess) and I (definitely) have been
arguing.

In fact, I am quite sure that MWI in it's current form implies that not
everything (a priori physically plausible) happens - interference of
histories is (I think) showing us that.

With COMP it is not so clear.

Best Wishes,
Günther

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[Bruno Marchal]

Le 05-mars-09, à 11:10, Günther Greindl a écrit :

>
> HI Bruno,
>
>>>> Indeed, that would be like if a number could make disappear another
>>>> number. Even a God cannot do that!
>>> The idea would be rather that some continuations would correspond
>>> to non-existent numbers, like, say, the natural number between 3 and
>>> 4.
>>
>> I am not sure I understand. If the continuation uses non existent
>> numbers, the continuation does not exist, or it is an inconsistent
>> continuation, that is a cul-de-sac world. I can prove that 0 = 1, if
>> there is a natural number between 3 and 4.
>> A god cannot make disappear a natural number, nor introduce a natural
>> number where there is none. It seems to me.
>
> We are just talking a little past each other. To recap:
>
> I initially meant that it would be possible, in a teleportation
> experiment, that aliens prevent any copies from being instantiated.
>
> You then said that that would be equivalent to making disappear a
> number, which is not possible.
>
> My idea was rather that the instantiations would not correspond to
> numbers in the first place

But that would violate the comp assumption.



> - that is why the aliens could destroy the
> machine (it follows from 3-det that something _had_ to happen to
> prevent
> successor states which wouldn't correspond to numbers).


But machines are secondary. The "physical machines" are pattern
emerging in the mind of persons themselves emerging from the relation
between numbers. I don't see how aliens could manage a machine not to
have successors.



>
> So, of course nobody can introduce new numbers - but if there were
> successor states which would require new numbers, that would mean that
> QI is false - there a cul de sacs (modus tollens).

If a successor state requires something impossible, *that* successor
state will be impossible, but it does not mean there will not be other
successor states, indeed, for mind corresponding on machine's state, a
continuum of successor states exists.

Best,

Bruno



http://iridia.ulb.ac.be/~marchal/


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[Bruno Marchal]

Le 05-mars-09, à 11:15, Günther Greindl a écrit :

>
> Hi Stathis,
>
>>> It is at least conceivable that the collection of particles that is
>>> me
>>> could undergo some environmental interaction such that *all* the
>>> following entangled branches decohere into states that do *not* map
>>> to
>>> the emergent class of "me, being conscious."  Then I would be dead.
>>
>> It seems possible, but in that case the QTI would be wrong. Also, it
>> isn't clear that the MWI says that everything that can happen, does
>> happen, even though that is how it is sometimes characterised.
>
> Indeed, that is what Jonathan (I guess) and I (definitely) have been
> arguing.

We agree. The MWI does forbid world in which 1 = 0. Many things remains
impossible in the MWI.


>
> In fact, I am quite sure that MWI in it's current form implies that not
> everything (a priori physically plausible) happens - interference of
> histories is (I think) showing us that.

Sure. But note that "a lot of things happens", including the white
rabbits and aberrant histories. Quantum intefrence and decoherence
explains why those aberrant histories are relatively rare.

>
> With COMP it is not so clear.

Something subtle happens with comp. The "scientist" cannot prevent the
apparition of cul-de-sac everywhere, but this is the reason that he has
to abandon science for theology once he decide to compute
probabilities. he will does that by defining the probability by an
explicit appeal to self-consistency (= the move from Bp to Bp & Dt; the
"Dt" suppresses the cul-de-sac). With comp, to believe in a next
instant or in a successor state is already based on an act of faith.
But this makes a strong restriction of what is possible, and harder to
eliminate the white rabbits. Cf, with comp we have to derive QM. We
just cannot assume it.

Bruno





http://iridia.ulb.ac.be/~marchal/


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[Stathis Papaioannou-2]

2009/3/5 Bruno Marchal <marchal@...>:

> Sure. But note that "a lot of things happens", including the white
> rabbits and aberrant histories. Quantum intefrence and decoherence
> explains why those aberrant histories are relatively rare.

Could it be that some things which seem physically possible, like the
matter in my keyboard spontaneously rearranging itself into a
miniature fire-breathing dragon, are actually impossible under MWI,
i.e. don't occur in any branch of the multiverse?



--
Stathis Papaioannou

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[Bruno Marchal]

On 05 Mar 2009, at 12:43, Stathis Papaioannou wrote:

>
> 2009/3/5 Bruno Marchal <marchal@...>:
>
>> Sure. But note that "a lot of things happens", including the white
>> rabbits and aberrant histories. Quantum intefrence and decoherence
>> explains why those aberrant histories are relatively rare.
>
> Could it be that some things which seem physically possible, like the
> matter in my keyboard spontaneously rearranging itself into a
> miniature fire-breathing dragon, are actually impossible under MWI,
> i.e. don't occur in any branch of the multiverse?

If we take seriously *classical* quantum mechanics into account, or  
even *special relativistic quantum mechanics* into account, I don't  
see how we could prevent such happening (your keyboard becoming a  
dragon) in the multiverse. It just follows from the math. Of course  
the probability that your keyboard become a firing dragon in your  
branch is much little than winning the big lottery every nanosecond  
during 100^100 millennia. The main reason is that in such theories  
position and momentum are described by continuous variables, and the  
quantum splitting or observers differentiation operate on the  
continuum. They are even a continuum of variant among your possible  
dragons, but this remains relatively rare.

Of course we have good reason to dismiss both classical quantum  
mechanics and special relativistic mechanics as the "real theory",  
given that they "forget" the unavoidable problem of quantization of  
gravitation, and thus of space-time.

If we take into account gravitation, we have a choice of theories on  
which physicists are still debating a lot. I would say that with the  
"superstring" sort of theories, the multiverse generates still a  
continuum of differentiation of stories, and that keyboard-dragon  
transformation will still happen in many branches (but will still be  
very rare, for the same reason as above). If we take the Loop-Gravity  
kind of theories, then gravitation (which curves space-time) is  
properly quantized, and we get eventually a discrete space-time. In  
that case, if we add the assumption that the physical universe is  
sufficiently little, it may be that the keyboard-dragon transformation  
does not occur, in the resulting finite or enumerable multiverse. Now,  
*this* would be a problem for comp, because comp implies indeed that  
everything consistent happens somewhere indeed (unless Günther is  
right and that some comp super-selection rule applies, but I don't see  
where such super-selection could come from).

Of course keyboard-dragon types of transformations are utterly NOT  
verifiable, even in the ironical first person way of quantum or comp  
suicide. If you decide to kill yourself until your keyboard transforms  
itself into a firing dragon, a "simple" evaluation of the  
probabilities will show that you have 99,9999... % of chance of  
surviving only with a brain making you believing that such a  
transformation has occurred, when it has not. It is the general  
practical weakness of comp or quantum suicide: if you ask for  
something *near-impossible",  suicide will send you in dreamland (1  
person view), and probably in a asylum (3 person view).


Bruno



http://iridia.ulb.ac.be/~marchal/




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[russell standish-2]

On Thu, Mar 05, 2009 at 04:10:15PM +0100, Bruno Marchal wrote:

>
> Of course keyboard-dragon types of transformations are utterly NOT  
> verifiable, even in the ironical first person way of quantum or comp  
> suicide. If you decide to kill yourself until your keyboard transforms  
> itself into a firing dragon, a "simple" evaluation of the  
> probabilities will show that you have 99,9999... % of chance of  
> surviving only with a brain making you believing that such a  
> transformation has occurred, when it has not. It is the general  
> practical weakness of comp or quantum suicide: if you ask for  
> something *near-impossible",  suicide will send you in dreamland (1  
> person view), and probably in a asylum (3 person view).
>

Excellent point!

--

----------------------------------------------------------------------------
Prof Russell Standish                  Phone [phone] (mobile)
Mathematics                        
UNSW SYDNEY 2052                 hpcoder@...
Australia                                http://www.hpcoders.com.au
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[Brent Meeker-2]

Bruno Marchal wrote:

>
> On 05 Mar 2009, at 12:43, Stathis Papaioannou wrote:
>
>> 2009/3/5 Bruno Marchal <marchal@...>:
>>
>>> Sure. But note that "a lot of things happens", including the white
>>> rabbits and aberrant histories. Quantum intefrence and decoherence
>>> explains why those aberrant histories are relatively rare.
>> Could it be that some things which seem physically possible, like the
>> matter in my keyboard spontaneously rearranging itself into a
>> miniature fire-breathing dragon, are actually impossible under MWI,
>> i.e. don't occur in any branch of the multiverse?
>
>
> If we take seriously *classical* quantum mechanics into account, or  
> even *special relativistic quantum mechanics* into account, I don't  
> see how we could prevent such happening (your keyboard becoming a  
> dragon) in the multiverse. It just follows from the math. Of course  
> the probability that your keyboard become a firing dragon in your  
> branch is much little than winning the big lottery every nanosecond  
> during 100^100 millennia. The main reason is that in such theories  
> position and momentum are described by continuous variables, and the  
> quantum splitting or observers differentiation operate on the  
> continuum. They are even a continuum of variant among your possible  
> dragons, but this remains relatively rare.
>
> Of course we have good reason to dismiss both classical quantum  
> mechanics and special relativistic mechanics as the "real theory",  
> given that they "forget" the unavoidable problem of quantization of  
> gravitation, and thus of space-time.
>
> If we take into account gravitation, we have a choice of theories on  
> which physicists are still debating a lot. I would say that with the  
> "superstring" sort of theories, the multiverse generates still a  
> continuum of differentiation of stories, and that keyboard-dragon  
> transformation will still happen in many branches (but will still be  
> very rare, for the same reason as above). If we take the Loop-Gravity  
> kind of theories, then gravitation (which curves space-time) is  
> properly quantized, and we get eventually a discrete space-time. In  
> that case, if we add the assumption that the physical universe is  
> sufficiently little, it may be that the keyboard-dragon transformation  
> does not occur, in the resulting finite or enumerable multiverse.

This is what I've suggested before.  There may be a smallest non-zero
probability, so quantum evolution is not strictly unitary and after sufficient
decoherence the off diagonal terms of the reduced density matrix become strictly
zero.

Brent

>Now,  
> *this* would be a problem for comp, because comp implies indeed that  
> everything consistent happens somewhere indeed (unless Günther is  
> right and that some comp super-selection rule applies, but I don't see  
> where such super-selection could come from).
>
> Of course keyboard-dragon types of transformations are utterly NOT  
> verifiable, even in the ironical first person way of quantum or comp  
> suicide. If you decide to kill yourself until your keyboard transforms  
> itself into a firing dragon, a "simple" evaluation of the  
> probabilities will show that you have 99,9999... % of chance of  
> surviving only with a brain making you believing that such a  
> transformation has occurred, when it has not. It is the general  
> practical weakness of comp or quantum suicide: if you ask for  
> something *near-impossible",  suicide will send you in dreamland (1  
> person view), and probably in a asylum (3 person view).
>
>
> Bruno
>
>
>
> http://iridia.ulb.ac.be/~marchal/
>
>
>
>
> >
>

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