Re: Quantum Immortality and Information Flow

2005-12-31 Thread Johnathan Corgan
Stathis Papaioannou wrote:

 There are many ways to escape from this scenario. If you are Tookie, you
 will find yourself shunted into increasingly less likely situations: not
 being caught in the first place; being caught but not being found
 guilty; being sentenced to death but getting off on appeal; being
 pardoned by the Governer at the last moment; finding that you are one of
 the 1/billion people who have a natural resistance to the lethal agent.

Only your last scenario is causally connected to having received a
lethal injection.  What does shunted mean in the above?  Once I
experience having had the injection, how would I get shunted to any of
the preceding outcomes?

 If that all falls through, you might find that your arrest and execution
 was all part of a dream, or that you were actually executed but your
 head was preserved and you were resurrected as a computer upload in the
 future, or you were resurrected as a result of brute force emulation of
 every possible human mind in the very far future. These latter
 possibilities may be more likely than quantum tunneling to a tropical
 island, but in the final analysis, however unlikely the escape route may
 be, if its probability is non-zero, then it *has* to happen, doesn't it?

These scenarios are all causally connected to having been lethally
injected.  But your final question goes to the heart of the issue I
raised.  What is the likeliest scenario which includes the memory of
being lethally injected?  Are there always non-zero probability
outcomes, which, according to MWI, must be realized somewhere?

-Johnathan



Re: Quantum Immortality and Information Flow

2005-12-31 Thread Johnathan Corgan
Saibal Mitra wrote:

 To me it seems that the notion of ''successor'' has to break down at cases
 where the observer can die. The Tookies that are the most similar to the
 Tookie who got executed are the ones who got clemency. There is no objective
 reason why these Tookies should be excluded as ''successors''. They miss the
 part of their memories about things that happened after clemency was denied.
 Instead of those memories they have other memories. We forget things all the
 time. Sometimes we remember things that didn't really happen. So, we allow
 for information loss anyway. My point is then that we should forget about
 all of the information contained in the OM and just sample from the entire
 set of OMs.

(After being away for a couple weeks, I'd like to follow up with yours
and others replies.)

I find this line of argument hard to follow.  I think where we differ is
that I assume there must be some physical causality connecting observer
moments.

That is, if a person is in physical state A and is experiencing state
E(A), then their next subjective moment E(B) must have some connected,
causal path between physical state A and physical state B. This
reasoning makes the materialist assumption that subjective experience E
is entirely defined by the physical state of the observer.

According to MWI, physical state A actually evolves into a superposition
of discrete physical states B, each with a different density or
measure.  So, by the logic of the previous paragraph, subjective
experience E(A) must evolve into a superposition of discrete Es, each a
function of the particular discrete physical state B it arises from, and
each with a particular measure.

Some subset of this superposition of physical states B, however, do not
support the creation of subjective experience (say, where the person has
died.)  So some proportion of E(B)'s are null.

So my original question about what is happening to Tookie now can be
rephrased as the following thought experiment:

Physical state A is Tookie lying on a gurney, experiencing E(A), which
is getting injected with lethal toxin by the State of California.

Clearly, the vast majority of the elements of superposition of states B
which follow the execution are with him being dead, and do not give rise
to any subjective experience at all.

What are the possibilities for causally connected physical states which
don't involve his death?  Which B's exist which continue to give rise to
new E(B)'s?

In other words, which observer moments for Tookie exist which include
the memories of his having received the lethal injection, but not of
dying as a result?

Does there have to be any at all?  QTI says yes, there must be, and no
matter how unlikely--there is always escape in some form.  What was
Tookie's?

-Johnathan



Re: Quantum Immortality and Information Flow

2005-12-20 Thread Bruno Marchal

Le 16-déc.-05, à 16:49, Stathis Papaioannou a écrit :


It may be easy to find logical flaws in the above credo, but I maintain that it is so deeply ingrained in each of us that it would be very difficult to overcome, except perhaps on the intellectual level. 



OK but that would not make sense. I don't think any third person (intellectual) belief can put any doubt on a first person conviction. To learn that the sun is not the one going around the earth will never change our  conviction that the sun apparently turns around us.
Many difficulties are easier to be approached when we keep up explicitly the 1-3 distinction.





One could imagine other beliefs about personal identity that might have evolved if there were the appropriate selection pressure; for example, identifying as part of a group or swarm organism. The point is, our belief is not scientifically or philosophically right; it is just our belief.



All right. I will say more because some people ask me out of line what are G, G*, and G* \  G.
I am thinking to define machine science by what machine can prove correctly about themselves, and by machine theology what machine can hope correctly about themselves ; where a machine proves a proposition p correctly when the machine proves p and p is true, and a machine hopes p correctly when the machine hopes p and p is true.
This is a non normative definition of science and theology because such definition does not forces us to revise any scientific or theological prejudices we could have, a priori.

Now let M be a sound machine. By definition a sound machine is a machine which proves only true propositions. Let us write Bp the proposition that the machine M proves p. To say that the machine is sound is equivalent as saying that IF the machine proves p THEN p is true. This means the proposition Bp -> p is always true, whatever particular proposition p represents (assuming of course that p is written in some language the machine can understand or at least manipulates formally).

So for each p the proposition Bp -> p is true for M, and this is just equivalent as saying that the machine is sound. Question: is it true that for each p B(Bp -> p) will be true?
Let p b any obviously false sentence like a contradiction (like q  ~q, or better the constant f). If B(Bp -> p) was always true, we would have B(Bf -> f); which means (giving that Ba means that the machine proves a) that the machine proves Bf -> f. But Bf -> f is equivalent with ~Bf.  (Verify with a thruth table in case of doubt). But ~Bf means that the machine does not prove the false, but this means that the machine is consistent.  So if B(Bp -> p) was true for any p, then the machine could prove its own consistency: the machine would prove 
Bf -> f, that is ~Bf (consistency; you can write it also Dt). And this is in contradiction with Godel's second incompleteness theorem. 
So soundness (Bp -> p) or more particularly consistency (Bf -> f) are typical example of true propositions about the sound machine M, that the machine M is unable to prove. So soundness and consistency, thanks to the second incompleteness theorem of Godel, are example of proposition that such a machine can hope for, and hope correctly, as WE know (giving that we talk by definition about a sound machine).

A natural question is the following: does such a B follow some modal logical laws? The answer is affirmative.

Basically, the theorem of SOLOVAY is just that for such sound machine, the modal logic G formalises completely the science of the machine, and the modal logic G* formalizes completely the theology of the machine.

G has the following axioms and rules:
K   B(p -> q) -> (Bp -> Bq)
L   B(Bp -> p) -> Bp
Rules : modus ponens (if the machine proves A and if the machine proves A -> B then the machine will prove B) and necessitation (if the machine proves A then the machine will prove BA).

G* has the following axioms and rules:
As axioms: all theorems of G, +
Bp -> p  (the machine is sound)
Rules: modus ponens (ONLY!).

In general G (and G*)  are thought as being the set of theorems which can be derived from the axioms and rules given, and thus are infinite sets of formulas. What I note G* \ G is the set difference of the (infinite) set G* and G, that is: pure theology: the set of everything which is true for the machine but that the machine cannot prove. The machine can only hope such proposition, and WE know that such machine can correctly hope those propositions.

I must go. Here are important formulas (and their standard name) that we will meet again and again. I let you think about which sort of multiverse (Kripke frame) makes each of those formula automatically true, whatever the illumination (the valuation of the sentence letters) is.

K = B(p->q) -> (Bp -> Bq)
t = Bp -> p,
4 = Bp -> BBp,
B = p -> BDp,
D = Bp -> Dp,
5 = Dp -> BDp,
C = Dp -> ~ BDp,
L = B(Bp->p)->Bp,
Grz = B(B(p -> Bp) -> p) -> p.


Bruno


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


Re: Quantum Immortality and Information Flow

2005-12-16 Thread Saibal Mitra
Hi Bruno,

Well, even if you can derive the laws of physics as we know them (in some
approximation), you still can't do an experiment to prove that quantum
suicide works. It can only be proven to the experimentor himself. This means
that the absolute measure cannot be ruled out experimentally.


- Original Message - 
From: Bruno Marchal [EMAIL PROTECTED]
To: Saibal Mitra [EMAIL PROTECTED]
Cc: everything-list@eskimo.com
Sent: Thursday, December 15, 2005 01:25 PM
Subject: Re: Quantum Immortality and Information Flow



 Le 15-déc.-05, à 03:04, Saibal Mitra a écrit :


 
  To me it seems that the notion of ''successor'' has to break down at
  cases
  where the observer can die. The Tookies that are the most similar to
  the
  Tookie who got executed are the ones who got clemency. There is no
  objective
  reason why these Tookies should be excluded as ''successors''. They
  miss the
  part of their memories about things that happened after clemency was
  denied.
  Instead of those memories they have other memories. We forget things
  all the
  time. Sometimes we remember things that didn't really happen. So, we
  allow
  for information loss anyway. My point is then that we should forget
  about
  all of the information contained in the OM and just sample from the
  entire
  set of OMs.
 
  The notion of a ''successor'' is not a fundamental notion at all. You
  can
  define it any way you like.


 ?



  It will not lead to any conflict with any
  experiments you can think of.
 
 


 ?

 Counterexamples will appear if I succeed to explain more of the
 conversation with the lobian machines.

 But just with the Kripke semantics we have a base to doubt what you are
 saying here. Indeed, it is the relation of accessibility between OMs
 which determine completely the invariant laws pertaining in all OMs.
 For example, if the multiverse is reflexive the Bp - p is true in all
 OMs (that is, Bp - p is invariant for any walk in the multiverse). If
 the mutliverse is terminal of papaioannou-like) then Dt - ~BDt  is
 a law. In Kripke structure the accessibility relation determined the
 invariant laws.
 later, the modal logic is given by the machine interview, and from
 that, we will determine the structure of the multiverse, including the
 observable one.

 Bruno




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





Re: Quantum Immortality and Information Flow

2005-12-16 Thread Stathis Papaioannou

Saibal Mitra writes:


To me it seems that the notion of ''successor'' has to break down at cases
where the observer can die. The Tookies that are the most similar to the
Tookie who got executed are the ones who got clemency. There is no 
objective
reason why these Tookies should be excluded as ''successors''. They miss 
the
part of their memories about things that happened after clemency was 
denied.
Instead of those memories they have other memories. We forget things all 
the

time. Sometimes we remember things that didn't really happen. So, we allow
for information loss anyway. My point is then that we should forget about
all of the information contained in the OM and just sample from the entire
set of OMs.

The notion of a ''successor'' is not a fundamental notion at all. You can
define it any way you like. It will not lead to any conflict with any
experiments you can think of.


You are right about death with a (not completely up to date) backup of your 
mind being equivalent to memory loss, and you are right about the notion of 
a successor not being fundamental to physics. Nevertheless, we can still ask 
questions *given* our innate theory of personal identity, which has 
evolved to be very powerful and difficult to change, and very consistent 
from person to person. What this means is that if I were facing imminent 
execution, try as I might, I would not get much consolation from the belief 
that other versions of me in the multiverse will not be killed. In fact, I 
don't really care what happens to versions of me in parallel branches. What 
I care about is what is happening to me now, and what will happen to me in 
the future. When I consider my immediate future, I consider and worry about 
the fate of all those versions of me who remember almost everything about me 
up to and including the present moment, which for them will be a moment ago. 
 Once the future comes and I find myself to be one of the aforementioned 
versions, I immediately lose interest in all the other parallel versions, 
because they are no longer potentially me.


Using the above structure, at the point where I am just about to have the 
lethal injection, what I hope for is that there will be at least one version 
of me in the multiverse who has just experienced having the injection a 
moment ago, but has somehow survived. In other words, if one or more such 
versions exist anywhere in the multiverse, then this is necessary and 
sufficient for me to survive my execution.


It may be easy to find logical flaws in the above credo, but I maintain that 
it is so deeply ingrained in each of us that it would be very difficult to 
overcome, except perhaps on the intellectual level. One could imagine other 
beliefs about personal identity that might have evolved if there were the 
appropriate selection pressure; for example, identifying as part of a group 
or swarm organism. The point is, our belief is not scientifically or 
philosophically right; it is just our belief.


Stathis Papaioannou

_
Don’t just search. Find. Check out the new MSN Search! 
http://search.msn.click-url.com/go/onm00200636ave/direct/01/




Re: Quantum Immortality and Information Flow

2005-12-16 Thread Bruno Marchal

Hi Saibal,


Well, even if you can derive the laws of physics as we know them (in 
some

approximation), you still can't do an experiment to prove that quantum
suicide works.



I think you are completely right. It is even my main motivation for 
calling theology the modal logic G* (which contains all the 
propositional truth about the machine including those the machines 
cannot prove).






 It can only be proven to the experimentor himself.



Actually I am not even sure of that, although the experimentor can in a 
1-person view, believes he got evidences (but no proof). Actually I 
have no proof that I am alive.






This means
that the absolute measure cannot be ruled out experimentally.



OK. But how would you verify the absolute measure. Do you think you can 
derive the physical laws from it (without any physicalist prior, and 
by being coherent with the 1-3 distinction)?



See you tomorrow,

Bruno








- Original Message -
From: Bruno Marchal [EMAIL PROTECTED]
To: Saibal Mitra [EMAIL PROTECTED]
Cc: everything-list@eskimo.com
Sent: Thursday, December 15, 2005 01:25 PM
Subject: Re: Quantum Immortality and Information Flow




Le 15-déc.-05, à 03:04, Saibal Mitra a écrit :




To me it seems that the notion of ''successor'' has to break down at
cases
where the observer can die. The Tookies that are the most similar to
the
Tookie who got executed are the ones who got clemency. There is no
objective
reason why these Tookies should be excluded as ''successors''. They
miss the
part of their memories about things that happened after clemency was
denied.
Instead of those memories they have other memories. We forget things
all the
time. Sometimes we remember things that didn't really happen. So, we
allow
for information loss anyway. My point is then that we should forget
about
all of the information contained in the OM and just sample from the
entire
set of OMs.

The notion of a ''successor'' is not a fundamental notion at all. You
can
define it any way you like.



?




It will not lead to any conflict with any
experiments you can think of.





?

Counterexamples will appear if I succeed to explain more of the
conversation with the lobian machines.

But just with the Kripke semantics we have a base to doubt what you 
are

saying here. Indeed, it is the relation of accessibility between OMs
which determine completely the invariant laws pertaining in all OMs.
For example, if the multiverse is reflexive the Bp - p is true in all
OMs (that is, Bp - p is invariant for any walk in the multiverse). If
the mutliverse is terminal of papaioannou-like) then Dt - ~BDt  is
a law. In Kripke structure the accessibility relation determined the
invariant laws.
later, the modal logic is given by the machine interview, and from
that, we will determine the structure of the multiverse, including the
observable one.

Bruno




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






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




Re: Quantum Immortality and Information Flow

2005-12-16 Thread George Levy

Le 14-déc.-05, à 01:34, Stathis Papaioannou a écrit :

In the multiverse, only other people end up in dead ends. Although 
from a third person perspective every entity in the multiverse could 
be said to exist only transiently because at every point of an 
entity's history we can say that there sprouts a dead end branch of 
zero extent, from a first person perspective, these branches cannot 
by definition ever be experienced.


If the laws of physics are contingent on the continuation of 
consciousness, it is very well possible that a very large majority of 
branches are very short and dead ends. In other words every nanoseconds 
we suffer a thousand deaths through events which are perceived to be 
unlikely due to the  apparent stability of the physical laws, events 
such as proton decay, beta capture, nuclear fusion due to nucleus 
tunneling, etc...


Bruno Marchal wrote:


I know you have solved the only if part of following exercise:

(W, R) is reflexive iff  (W,R) respects Bp - p.

I will come back on the if part later.

Have you done this: showing that

(W,R) is a Papaioannou multiverse   iff(W,R) respects Dt 
- D(Bf).


Note that this question is a little bit academical. I have already 
explain how I will choose the modal logics. Actually I will not choose 
them, I will extract them from a conversation with the machine (and 
its guardian angel). This will leave no choice. It will happen that 
the formula
Dt - D(Bf) will appear in the discourse machine; indeed perhaps some 
of you know already that this is just the second incompleteness of 
Godel, once you interpret Bp by the machine proves p, coded in some 
language the machine can use.



George



Re: Quantum Immortality and Information Flow

2005-12-16 Thread Quentin Anciaux
Le Vendredi 16 Décembre 2005 02:18, vous avez écrit :
 This is true, but you can only experience being one person at a time. 
In fact I'd say I can only experience being me ;) If I experienced being 
another person I wouldn't be I.
 When 
 I contemplate what may happen to me tomorrow, I have to consider all the
 future versions of me in the multiverse as having equal right to consider
 themselves me. So if half the versions of me tomorrow are expected to
 suffer, I am worried, because I might be one of those who suffers. 
In fact you might not be, It's sure *you* will.
 But when 
 tomorrow comes and I am not suffering, I am relieved - even though those
 who are suffering have as much right to consider themselves the
 continuation of yesterday's version of me as I do. Our psychology creates
 an asymmetry between the present and the future when it comes to personal
 identity. Some on this list (eg. Lee Corbin) have argued that this is
 irrational: copies that are me in the future should also be considered
 me in the present and past. 
I agree with this statement.
 However, our psychological makeup is as it 
 is: our future encompasses many possibilities, but our present and past is
 fixed and single.
This is true, but if you encompass a multiverse/everything view then you 
cannot ask why am I not one of those that or that experience... Why am I 
still in a rationnal/induction working world ? You're not because if you 
were, you wouldn't ask this in the first place.


 Stathis Papaioannou

Regards,
Quentin Anciaux



Re: Quantum Immortality and Information Flow

2005-12-15 Thread Bruno Marchal


Le 14-déc.-05, à 01:34, Stathis Papaioannou a écrit :

In the multiverse, only other people end up in dead ends. Although 
from a third person perspective every entity in the multiverse could 
be said to exist only transiently because at every point of an 
entity's history we can say that there sprouts a dead end branch of 
zero extent, from a first person perspective, these branches cannot by 
definition ever be experienced.



All right.
Could I take this as a defence of the Papaioannou multiverse for some 
third person description: those where each world where you have a next 
state leads to a dead end?
I call them realist frames in Conscience  Mechanism. Sometimes they 
are called terminal frames in the literature.


I know you have solved the only if part of following exercise:

(W, R) is reflexive iff  (W,R) respects Bp - p.

I will come back on the if part later.

Have you done this: showing that

(W,R) is a Papaioannou multiverse   iff(W,R) respects Dt 
- D(Bf).


Note that this question is a little bit academical. I have already 
explain how I will choose the modal logics. Actually I will not choose 
them, I will extract them from a conversation with the machine (and its 
guardian angel). This will leave no choice. It will happen that the 
formula
Dt - D(Bf) will appear in the discourse machine; indeed perhaps some 
of you know already that this is just the second incompleteness of 
Godel, once you interpret Bp by the machine proves p, coded in some 
language the machine can use.


=
Exercises for those who begins the study of modal logics:
Does every one see that all the following formula are equivalent? :

Dt - ~B(Dt)
Dt - D(Bf)
BDt - Bf
~Bf - ~B(~Bf)


Those are equivalent (in all the modal logics we will meet), and the 
only things people should know to prove those equivalences are that:


1)
~Bp   is equivalent with D~p (not necessary p = possible not p)
~Dp is equivalent with B~p  (not possible p = necessary not p)
Bp is equivalent with ~D~p
Dp is equivalent with ~B~p

From this you can deduce a nice memo: a not ~ can jump over boxes by 
transforming  them into diamonds, and reciprocally:

For example:
~BBf is equivalent with Dt

and 2)
the contraposition law:  (A - B) is equivalent with (~B - ~A).


I urge people who have difficulties NOT to hesitate to ask me question 
OUT of line. Too bad to miss the marvel of all marvels (G and G*) for 
reason of math-notation-anxiety!!!


Bruno






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




Re: Quantum Immortality and Information Flow

2005-12-15 Thread Stathis Papaioannou

Quentin Anciaux writes:


Hi Jesse,

 unless you are willing to say that white rabbit universes have a
 lower absolute measure than stable-laws-of-nature universes, you have no
 justification for expecting that you are unlikely to experience such 
events

 in your future.

 Jesse

You have no justification, but in (everything like) multiverse, it is for 
sure

(probability 1) that an extension of your present self *will* experience
weird events. Because all possibilities are fullfiled in the multiverse...

The problem arise because of what we call I... the I that will 
experience

weird thing will remember being the present I... So when you say that you
have to explain why *you* are unlikely to experience weird event, who is
you ? All next you will remember being current you.


This is true, but you can only experience being one person at a time. When I 
contemplate what may happen to me tomorrow, I have to consider all the 
future versions of me in the multiverse as having equal right to consider 
themselves me. So if half the versions of me tomorrow are expected to 
suffer, I am worried, because I might be one of those who suffers. But when 
tomorrow comes and I am not suffering, I am relieved - even though those who 
are suffering have as much right to consider themselves the continuation of 
yesterday's version of me as I do. Our psychology creates an asymmetry 
between the present and the future when it comes to personal identity. Some 
on this list (eg. Lee Corbin) have argued that this is irrational: copies 
that are me in the future should also be considered me in the present 
and past. However, our psychological makeup is as it is: our future 
encompasses many possibilities, but our present and past is fixed and 
single.


Stathis Papaioannou

_
Don’t just search. Find. Check out the new MSN Search! 
http://search.msn.click-url.com/go/onm00200636ave/direct/01/




Re: Quantum Immortality and Information Flow

2005-12-14 Thread Quentin Anciaux
Hi Jesse,

 unless you are willing to say that white rabbit universes have a
 lower absolute measure than stable-laws-of-nature universes, you have no
 justification for expecting that you are unlikely to experience such events
 in your future.

 Jesse

You have no justification, but in (everything like) multiverse, it is for sure 
(probability 1) that an extension of your present self *will* experience 
weird events. Because all possibilities are fullfiled in the multiverse... 

The problem arise because of what we call I... the I that will experience 
weird thing will remember being the present I... So when you say that you 
have to explain why *you* are unlikely to experience weird event, who is 
you ? All next you will remember being current you.

Regards,
Quentin



Re: Quantum Immortality and Information Flow

2005-12-14 Thread Quentin Anciaux
Hi,

the only explanation that I see fit in this context is an anthropic like 
argument.

To have this discussion about why we haven't seen/experienced weird things up 
till now is that we must be conscious observer that haven't seen/experienced 
weird things up till now ;) 

And only our next extensions that live in an universe where no weird things 
happen will continue to ask why don't I see weird things happening ?

Quentin

Le Mercredi 14 Décembre 2005 09:42, Quentin Anciaux a écrit :
 Hi Jesse,

  unless you are willing to say that white rabbit universes have a
  lower absolute measure than stable-laws-of-nature universes, you have no
  justification for expecting that you are unlikely to experience such
  events in your future.
 
  Jesse

 You have no justification, but in (everything like) multiverse, it is for
 sure (probability 1) that an extension of your present self *will*
 experience weird events. Because all possibilities are fullfiled in the
 multiverse...

 The problem arise because of what we call I... the I that will
 experience weird thing will remember being the present I... So when you
 say that you have to explain why *you* are unlikely to experience weird
 event, who is you ? All next you will remember being current you.

 Regards,
 Quentin



Re: Quantum Immortality and Information Flow

2005-12-14 Thread Johnathan Corgan
Stathis Papaioannou wrote:

 In the multiverse, only other people end up in dead ends. 

Kind of makes you wonder what Tookie is doing right now.  To us, he died
as a result of lethal injection.

What sort of successor observer-moments can follow a thing like that?

Better question--what is the most likely type of 1st-person
observer-moment that would follow experiencing lethal injection?

Sure, there is an infinitesimal probability that all his constituent
particles quantum-tunneled to a Pacific island paradise and right now
somewhere in the multiverse he's enjoying a drink with an umbrella in
it, thanking the fine State of California for his new life.

More likely, but still infinitesimally small, is the probability that
only the molecules of toxin in the injection syringe quantum-tunneled
away and right now there are execution officials puzzling over whether
to pardon him after this act-of-God miraculous reprieve from death.

But seriously, when the overwhelmingly vast majority of successor
moments to an instant in time are all 3rd-person dead-ends, what would
would be an example of a high-expectation 1st-person successor
observer-moment from the tiny sliver of physically possible (but
extremely unlikely) ones left?

Is there in fact always one left, no matter how unlikely?

-Johnathan



Re: Quantum Immortality and Information Flow

2005-12-14 Thread Bruno Marchal


Le 13-déc.-05, à 18:37, [EMAIL PROTECTED] a écrit :



In this context I'm talking about your comp multiverse.  Yes, our 
common sense experience sees history as one way.  But this is the 
problem.  Your requirement for LASE is that the accessibility relation 
is symmetrical.




I don't require LASE.   (I recall for the other: LASE is the modal 
formula p - BDp, its characteristic multiverse have a symmetrical 
accessibility relation)


It is just the main formula in a modal propositional quantum physics. 
LASE is an empirical discovery of the physicist (as re-expressed by 
modal logicians).

(I use LASE for: Little Abstract Schroedinger Equation).





This implies that it has to be just as consistent to go backwards in 
history as forwards.



You are going too much quickly here. Nobody said that we need to 
interpret the accessibility relation in a temporal way. LASE 
axiomatizes a relation of proximity among quantum states or quantum 
consistent histories, which can be seen in some block-multiverse.





From what you say above about the natural numbers, it seems that the 
comp assumption of natural numbers contradicts this.



Yes. And that explains why it takes me more than 20 years to resolve 
that apparent contradiction. But I do think like you that apparently 
there is a contradiction. The contradiction will disappear when we will 
take seriously the incompleteness phenomenon into account. Strangely 
enough perhaps.





I'd appreciate [your summary].  As part of it, I think I would need an 
explanation of what you mean by physical universe.



Fair enough. Actually this depends of the context. I promise to say 
more asap; 'cause I got a new wave of working duties here alas :(




It seems to me that your belief in the process of verification, when 
you talk about verifying comp physics vs. quantum physics, is 
equivalent to a belief in a physical universe.



I gave an argument that if comp is correct then the *appearance* of 
*observables* must be explained from the (mathematical) structure of 
the natural border of our (us = the hopefully lobian machines) 
ignorance (a psychological or theological predicate).
The argument is mainly the UDA + the movie-graph, and the machine 
ignorance is just the collection of its possible consistent extensions.

This is coherent with the RSSA measure-philosophy of many in this list.

Then I show that indeed any sound lobian machine who introspects 
herself deeply enough will find those laws of observability. And, so we 
can test comp by comparing those lobian observability laws with the 
observability laws infered by observation of the empirical reality.


Would we get a complete confirmation: this would entail a confirmation 
that the empirical laws emerge from the immaterial machine ignorance, 
not from a physical or substantial independent reality.


If you want I believe in empiry, not in a necessary primitively 
physical base for that empiry.
Well, assuming comp, I believe in a base which is necessarily not 
physicalist.
Like Chaitin has also observed (and also from incompleteness) even 
arithmetical reality can only be known, in great part, by observation, 
experiment with numbers.


Oops, must go now. Hope this helps a bit, but it will be clearer with 
the summary, I hope.


Bruno



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




Re: Quantum Immortality and Information Flow

2005-12-14 Thread Russell Standish
On Wed, Dec 14, 2005 at 03:18:16PM -0800, George Levy wrote:
 
 The only way to talk meaningfully about measure is when you can compare 
 two situations from a third person point of view: for example, if you 
 witness someone die from a freak event you could conclude that he 
 continued living in a world with lower measure than yours. This is a 
 third person point of view. However, from that person's point of view 
 (first person), the freak event never happened and therefore he will 
 consider his measure to be just as high as yours.
 
 George

One can talk about relative measure between two observer moments
connected via an accessibility relation from the first person. The
computation of this relative measure (which will in fact be a
probability distribution) is given by the Born rule.

Absolute measure (which will be complex in general) is a pure 3rd
person phenomenon, and not accessible to observer. I argue that the
absolute measure can be identified with the magnitude and phase angle
of the quantum mechanical statevector representing the observer
moment. These quantities are usually considered unphysical, as they
are inaccessible to the observer. Only relative phase angles can be
measured. Such an identification (complex absolute measure with statefunction
magnitude) appears to be a novel interpretation of QM ...

Cheers


-- 
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Re: Quantum Immortality and Information Flow

2005-12-14 Thread Saibal Mitra

- Original Message - 
From: Johnathan Corgan [EMAIL PROTECTED]
To: Stathis Papaioannou [EMAIL PROTECTED]
Cc: everything-list@eskimo.com
Sent: Wednesday, December 14, 2005 10:39 AM
Subject: Re: Quantum Immortality and Information Flow


 Stathis Papaioannou wrote:

  In the multiverse, only other people end up in dead ends.

 Kind of makes you wonder what Tookie is doing right now.  To us, he died
 as a result of lethal injection.

 What sort of successor observer-moments can follow a thing like that?

 Better question--what is the most likely type of 1st-person
 observer-moment that would follow experiencing lethal injection?

 Sure, there is an infinitesimal probability that all his constituent
 particles quantum-tunneled to a Pacific island paradise and right now
 somewhere in the multiverse he's enjoying a drink with an umbrella in
 it, thanking the fine State of California for his new life.

 More likely, but still infinitesimally small, is the probability that
 only the molecules of toxin in the injection syringe quantum-tunneled
 away and right now there are execution officials puzzling over whether
 to pardon him after this act-of-God miraculous reprieve from death.

 But seriously, when the overwhelmingly vast majority of successor
 moments to an instant in time are all 3rd-person dead-ends, what would
 would be an example of a high-expectation 1st-person successor
 observer-moment from the tiny sliver of physically possible (but
 extremely unlikely) ones left?

 Is there in fact always one left, no matter how unlikely?



To me it seems that the notion of ''successor'' has to break down at cases
where the observer can die. The Tookies that are the most similar to the
Tookie who got executed are the ones who got clemency. There is no objective
reason why these Tookies should be excluded as ''successors''. They miss the
part of their memories about things that happened after clemency was denied.
Instead of those memories they have other memories. We forget things all the
time. Sometimes we remember things that didn't really happen. So, we allow
for information loss anyway. My point is then that we should forget about
all of the information contained in the OM and just sample from the entire
set of OMs.

The notion of a ''successor'' is not a fundamental notion at all. You can
define it any way you like. It will not lead to any conflict with any
experiments you can think of.



Re: Quantum Immortality and Information Flow

2005-12-13 Thread Bruno Marchal


Le 13-déc.-05, à 02:07, Stathis Papaioannou a écrit :

From the third person perspective, the annihilation of the 10^100 
copies
could be seen as 10^100 dead ends. (In fact, when I originally 
proposed this experiment, Hal Finney thought it represented the 
ultimate in mass murder.) If I were one of the 10^100, however, I 
wouldn't be worried in the slightest about the prospect of dying, 
because as long as at least one copy survives, this guarantees that I 
survive. This may go again intuition, but if you give up the notion of 
an immaterial soul, there is no reason why there should be a one to 
one relationship between earlier and later versions of a person.


OK. But from this I deduce that we were agreeing. Eventually this means 
we don't take the dead ends into account when computing probabilities 
for future extensions of oneself.


Bruno


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




Re: Quantum Immortality and Information Flow

2005-12-13 Thread Bruno Marchal


Le 12-déc.-05, à 19:37, George Levy a écrit :




 Stathis Papaioannou wrote:

In addition to the above arguments, consider the problem from the 
point of view of the subject. If multiple copies of a person are 
created and run in parallel for a period, what difference does this 
make to his experience? It seems to me that there is no test or 
experiment the person could do which would allow him to determine if 
he is living in a period of high measure or low measure. If an OM is 
the smallest discernible unit of conscious experience, it therefore 
seems reasonable to treat multiple instantiations of the same OM as 
one OM.


 Yes Stathis, I agree with you completely.





This is delicate and I think we should really make the disctinction 
between the 3-OMs and the 1-OMs. Difference of measure of 3-OM does not 
change the quality of the 1-OMs experiences, but could change the 
relative probability of having some next 1-OMs.


To justify this, I point you on the UDA, or to the lobian interview. 
(We are coming back on this).







 Bruno wrote:
And this already comes from the fact that the 
indistinguishabilitty/distinguishabilitty crux is itself relative. 
By loosing memory something distinguishable can become 
indistinguishable, augmenting the class of (normal) self-consistent 
extensions.


 Bruno, I find this question extremely difficult. Is 
indistinguishability established at the physical level or at the 
psychological level?



Psychological. Remember that with comp we take for granted some amount 
of folk or Grandmother psychology (enough for saying purposefully yes 
to the doctor). But then by the UDA, comp entails the complete 
structure of the physical laws. Now the goal is to make the derivation 
of the physical laws, so that we can test comp by comparing the 
comp-physics with the traditional empirical physics. With such kind of 
approach it is just forbidden to invoke anything physical as granted; 
we can certainly not take a physical multiverse or a physically based 
indistinguishability for granted.








If we say it is established at the psychological level, then even 
mental errors ( ie.6+7=11) count in defining a whole world.




6+7=11 is not a mental error. It is just a false proposition. I guess 
you mean something like B(6+7=11). This is a *mental error*, where 
the mentality has been supposed to be captured by some modal 
epistemic logic B (a modal box). And then 6+7=11 is akin to a sort 
of white rabbit or flying pig, those which, of course we need still to 
justify the extreme rarity.






This is the ultimate in relativism. I can find reasons to go either 
way. (Ultimately Undecided?)



And now this makes sense indeed and the Ultimately Undecided is close 
to the Forever Undecided which will be tackle by the self-reference 
logics G and G*.








Then I am open that from the 1 point of view, fusion increases 
measure, duplication decreases measure; although from the 3 pov it is 
the contrary.


 I do not agree with you on this point Bruno.
 From the one person point of view measures remains constant just 
like the speed of light, the mass of an electron, or the number of 
points in a line 1 meter long or 1 kilometer long. (the number of 
points in a continuum is always the same no matter what the length of 
the line is). The one person always observes a continuum in the number 
of opportunities available to him no matter what his past history is.




That's true, but only for a notion of actual 1-OMs, not necessarily 
for the 3-prediction on some possible (future) 1-OMs.






 From the third person point of view, it makes sense to consider 
ratios in measures, just like it makes sense to take ratios of line 
segments of different lengths.



OK.


Bruno


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




Re: Quantum Immortality and Information Flow

2005-12-13 Thread Bruno Marchal


Le 12-déc.-05, à 18:07, Tom ([EMAIL PROTECTED]) a écrit :


In response to Stathis' thought experiment, to speak of an experiment 
being set up in a certain way is to base probabilities on an 
irrelevant subset of the whole, at least if the multiverse 
hypothesis is true.  In the Plenitude, there are an additional 10^100 
copies still existing, when you say that 10^100 copies are being 
shut-down.  Talking about these additional 10^100 copies is just as 
consistent as talking about the original 10^100 copies (even more 
consistent if you consider Bruno's statement about cul-de-sacs.


In the Plenitude, everything washes out to zero.  And Bruno, I would 
even say that all consistent histories wash out to zero.



I am not sure why you say this.




Bruno, I've been following your posts about Kripke semantics and have 
done the exercises, including the one about showing that you need a 
symmetrical accessibility relation to have LASE.


Nice !



However, my initial reaction still is that choosing a particular modal 
logic is scary to me, sending up red flags about hidden assumptions 
that are being made in the process.  But I will continue to follow you 
as you present your case.





Actually I do agree with you. But in the present case, that is with 
comp as I defined it (or much weaker assumption really) we will not to 
have to make a choice on the modal logics, they will be given by the 
interview of the lobian machine. Precisely G (and G*) will appear to be 
the complete and sound logic of the provable (and true) 
self-referential statements made by a sound or self-referentially 
correct machine. This is a consequence of a theorem in pure 
mathematics: Solovay theorem.


Then, the translation of the UDA and in particular of the 1 and 3 
notions will lead to the other modal logics we need, without us adding 
more (hidden) assumptions than the comp one (or much weaker).








Earlier Stathis wrote:

Bruno: OK but with comp I have argued that OMs are not primitive but
are generated, in platonia, by the Universal Dovetailer. A 3- OM is 
just an UD-accessible state, and the 1-OMs inherit relative 
probabilities from the computer science theoretical structuring of the 
3-OMs.


Are OMs directly generated by the UD, or does the UD generate the
physical (apparently) universe, which leads to the evolution of 
conscious beings, who then give rise to OMs?


Stathis Papaioannou


It's interesting that symmetry (Bruno's requirement for LASE) has come 
up lately, because Stathis' question seems to be what we are all 
wondering.  That's the bottom line of multiverse theories:  Where does 
the symmetry breaking come from?





Actually comp put a big assymmetry at the start (the natural numbers: 
0, 1, 2, 3, 4, ...), and my question for years was how to get the 
symmetry which apparently lives at the bottom of physics (already 
classical physics, still more with QM-without collapse).









 I maintain still that it can't come from the multiverse itself.




But which multiverse? remember that the QM, or the existence of any 
physical multiverse are not among the hypothesis. Indeed the UDA forces 
us to justify completely the appearances of a physical multiverse.







Even considering only consistent histories, there is no asymmetry to 
be found.




This astonishes me a little bit. The very notion of history, it seems 
to me, is assymetrical. But then I am not sure if you are talking about 
the comp consistent extensions of some machine (the comp histories) or 
the quantum histories of Everett, Hartle, and Co. ?






 I maintain that it needs to come from outside the multiverse, which 
is something that we cannot explain.




It certainly (with comp) needs to be explain from outside any notion of 
physical multiverse.
Then the truth-provability gap (capture by the modal logic G* \ G, that 
is the set difference between the provable self-referential statements 
and the true self-referential statements) will explain why we cannot 
explain that something.

I should perhaps make some summary.


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




Re: Quantum Immortality and Information Flow

2005-12-13 Thread daddycaylor

Stathis wrote:


Tom Caylor writes: 
 
In response to Stathis' thought experiment, to speak of an experiment 

being

set up in a certain way is to base probabilities on an irrelevant
subset of the whole, at least if the multiverse hypothesis is true. 

In the
Plenitude, there are an additional 10^100 copies still existing, when 

you
say that 10^100 copies are being shut-down. Talking about these 

additional
10^100 copies is just as consistent as talking about the original 

10^100
copies (even more consistent if you consider Bruno's statement about 

cul-de-sacs. 

 
In the Plenitude, everything washes out to zero. And Bruno, I would 

even

say that all consistent histories wash out to zero. 

 
Doesn't this ignore the concept of measure in the multiverse? If I 

buy a lottery
ticket there are an infinite number of versions of me who win and an 

infinite

number of versions who lose, but in some sense there have to be more
losers than winners, which is why I don't buy lottery tickets. 
 
Stathis Papaioannou 


It seems to me that as soon as we talk about measure, it is equivalent 
to talking about one (physical!) universe.  This is similar to your 
George Levy's taking the ratio of the lengths of two line segments.  
You don't need a multiverse to do that.  I think that talking of 
measure in the multiverse is taking a common sense thing in a single 
universe and (erroneously) trying to make it make sense in the 
multiverse.  I don't think it works.  So yes I'm ignoring something 
that doesn't work, in my view.  I brought up the problem of the 
additional 10^100 copies, but your bringing up the word measure 
doesn't solve it.  The reason why you don't buy lottery tickets could 
just as easily be explained in a single universe.


Tom Caylor



Re: Quantum Immortality and Information Flow

2005-12-13 Thread daddycaylor

Bruno wrote:

Le 12-déc.-05, à 18:07, Tom ([EMAIL PROTECTED]) a écrit : 

 ...
In the Plenitude, everything washes out to zero. And Bruno, I would
even say that all consistent histories wash out to zero. 
 

I am not sure why you say this. 


See below.
 
It's interesting that symmetry (Bruno's requirement for LASE) has 

come

up lately, because Stathis' question seems to be what we are all
wondering. That's the bottom line of multiverse theories: Where does
the symmetry breaking come from? 


Actually comp put a big assymmetry at the start (the natural numbers:
0, 1, 2, 3, 4, ...), and my question for years was how to get the 

symmetry
which apparently lives at the bottom of physics (already classical 

physics,

still more with QM-without collapse). 


See below.
 

I maintain still that it can't come from the multiverse itself. 


But which multiverse? remember that the QM, or the existence
of any physical multiverse are not among the hypothesis. Indeed
the UDA forces us to justify completely the appearances of a 

physical multiverse.

See below. 


Even considering only consistent histories, there is no asymmetry to
be found. 
 
This astonishes me a little bit. The very notion of history, it 

seems to me,
is assymetrical. But then I am not sure if you are talking about the 

comp
consistent extensions of some machine (the comp histories) or the 

quantum

histories of Everett, Hartle, and Co. ? 

 
In this context I'm talking about your comp multiverse.  Yes, our 
common sense experience sees history as one way.  But this is the 
problem.  Your requirement for LASE is that the accessibility relation 
is symmetrical.  This implies that it has to be just as consistent to 
go backwards in history as forwards.  From what you say above about the 
natural numbers, it seems that the comp assumption of natural numbers 
contradicts this.



I maintain that it needs to come from outside the multiverse, which
is something that we cannot explain. 

It certainly (with comp) needs to be explain from outside any notion 

of
physical multiverse. Then the truth-provability gap (capture by the 

modal
logic G* \ G, that is the set difference between the provable 

self-referential
statements and the true self-referential statements) will explain 

why we

cannot explain that something. I should perhaps make some summary.
 
Bruno
http://iridia.ulb.ac.be/~marchal/ 


I'd appreciate it.  As part of it, I think I would need an explanation 
of what you mean by physical universe.  It seems to me that your 
belief in the process of verification, when you talk about verifying 
comp physics vs. quantum physics, is equivalent to a belief in a 
physical universe.


Tom Caylor



Re: Quantum Immortality and Information Flow

2005-12-13 Thread George Levy

Bruno Marchal wrote:

we are conscious only because we belong to a continuum of infinite 
never ending stories ...
...that's what the lobian machine's guardian angel  G* says about 
that: true and strictly unbelievable. 


Bruno
Since you agree that the number of histories is on a continuum, you must 
accept that no matter how large or small a segment of the continuum is 
considered, the number of histories is the same. Hence measure is the 
same for any observer.


George



Re: Quantum Immortality and Information Flow

2005-12-13 Thread daddycaylor
The reason why you don't buy lottery tickets could just as easily be 

explained in a single universe. 

I short-changed my argument.  I should've said, The reason why you 
don't buy lottery tickets can only be explained in a single universe.

 
Tom Caylor 



Re: Quantum Immortality and Information Flow

2005-12-13 Thread Jesse Mazer

Tom Caylor wrote:




The reason why you don't buy lottery tickets could just as easily be

explained in a single universe. 

I short-changed my argument.  I should've said, The reason why you don't 
buy lottery tickets can only be explained in a single universe.

 
Tom Caylor 



If you don't accept a measure on the entire multiverse, then you're not 
going to have any solution to what on this list is usually called the white 
rabbit problem, explaining why you don't expect to see weird events like 
talking white rabbits or Harry Potter style magic or 300 successive lottery 
wins. After all, there should be possible worlds within the multiverse where 
everything up to today is just the same as in a normal universe where the 
laws of nature stay stable, but after that point the probabilities of 
strange white-rabbit-style events radically increase. Since your experience 
up to the present is compatible with either type of universe, unless you are 
willing to say that white rabbit universes have a lower absolute measure 
than stable-laws-of-nature universes, you have no justification for 
expecting that you are unlikely to experience such events in your future.


Jesse




Re: Quantum Immortality and Information Flow

2005-12-13 Thread daddycaylor

Jesse wrote:

Tom Caylor wrote: 

 

The reason why you don't buy lottery tickets could just as easily be 

explained in a single universe.  
 
I short-changed my argument. I should've said, The reason why you
don't buy lottery tickets can only be explained in a single 

universe. 

  
Tom Caylor  
 

If you don't accept a measure on the entire multiverse, then you're
not going to have any solution to what on this list is usually called 

the

white rabbit problem, explaining why you don't expect to see weird
events like talking white rabbits or Harry Potter style magic or 300
successive lottery wins. After all, there should be possible worlds
within the multiverse where everything up to today is just the same
as in a normal universe where the laws of nature stay stable, but
after that point the probabilities of strange white-rabbit-style events
radically increase. Since your experience up to the present is
compatible with either type of universe, unless you are willing to
say that white rabbit universes have a lower absolute measure than
stable-laws-of-nature universes, you have no justification for 

expecting

that you are unlikely to experience such events in your future. 
 
Jesse


The white rabbit problem is a problem only for multiverse believers.

Tom



Re: Quantum Immortality and Information Flow

2005-12-13 Thread daddycaylor

The white rabbit problem is a problem only for multiverse believers. 


By the way, thanks for the reference to rabbits.  It caused a 
rabbit-repellent ad to appear in the margin of the archive.  It is 
lemon-scented (and another one is fox-scented!) and this will be more 
pleasant for me than the last garlic-and-rotten-egg scented one I tried 
in my back yard.  But these aren't white rabbits.


Tom



Re: Quantum Immortality and Information Flow

2005-12-13 Thread Stathis Papaioannou

Tom Caylor writes:

It seems to me that as soon as we talk about measure, it is equivalent to 
talking about one (physical!) universe.  This is similar to your George 
Levy's taking the ratio of the lengths of two line segments.  You don't 
need a multiverse to do that.  I think that talking of measure in the 
multiverse is taking a common sense thing in a single universe and 
(erroneously) trying to make it make sense in the multiverse.  I don't 
think it works.  So yes I'm ignoring something that doesn't work, in my 
view.  I brought up the problem of the additional 10^100 copies, but your 
bringing up the word measure doesn't solve it.  The reason why you don't 
buy lottery tickets could just as easily be explained in a single universe.


Are you saying that probability can only mean anything in a single physical 
universe? And that because apparently probability does have meaning, this is 
evidence that there is only a single physical universe? Would you go further 
and say that the universe must be finite, because many of the properties of 
the multiverse are mirrored in a single infinite universe?


Stathis Papaioannou

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Re: Quantum Immortality and Information Flow

2005-12-13 Thread Stathis Papaioannou


In the multiverse, only other people end up in dead ends. Although from a 
third person perspective every entity in the multiverse could be said to 
exist only transiently because at every point of an entity's history we can 
say that there sprouts a dead end branch of zero extent, from a first person 
perspective, these branches cannot by definition ever be experienced.


Stathis Papaioannou


Le 13-déc.-05, à 02:07, Stathis Papaioannou a écrit :


From the third person perspective, the annihilation of the 10^100 copies
could be seen as 10^100 dead ends. (In fact, when I originally proposed 
this experiment, Hal Finney thought it represented the ultimate in mass 
murder.) If I were one of the 10^100, however, I wouldn't be worried in 
the slightest about the prospect of dying, because as long as at least one 
copy survives, this guarantees that I survive. This may go again 
intuition, but if you give up the notion of an immaterial soul, there is 
no reason why there should be a one to one relationship between earlier 
and later versions of a person.


OK. But from this I deduce that we were agreeing. Eventually this means we 
don't take the dead ends into account when computing probabilities for 
future extensions of oneself.


Bruno


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



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Re: Quantum Immortality and Information Flow

2005-12-13 Thread Jesse Mazer

George Levy:



Bruno Marchal wrote:

we are conscious only because we belong to a continuum of infinite never 
ending stories ...
...that's what the lobian machine's guardian angel  G* says about that: 
true and strictly unbelievable.


Bruno
Since you agree that the number of histories is on a continuum, you must 
accept that no matter how large or small a segment of the continuum is 
considered, the number of histories is the same. Hence measure is the same 
for any observer.


The whole concept of measure is based on assigning different probabilities 
to different infinite sets--the fact that two sets have the same cardinality 
doesn't imply they must have the same measure. For example, any continuous 
probability distribution used in statistics (the bell curve, for example) 
can be used to assign a measure to an arbitrary finite interval (which 
necessarily contains an infinite number of points), the measure just being 
the area under the curve over that interval.


Jesse




Re: Quantum Immortality and Information Flow

2005-12-13 Thread George Levy

Jesse Mazer wrote:


George Levy:


Bruno Marchal wrote:

we are conscious only because we belong to a continuum of infinite 
never ending stories ...
...that's what the lobian machine's guardian angel  G* says about 
that: true and strictly unbelievable.


Bruno
Since you agree that the number of histories is on a continuum, you 
must accept that no matter how large or small a segment of the 
continuum is considered, the number of histories is the same. Hence 
measure is the same for any observer.



The whole concept of measure is based on assigning different 
probabilities to different infinite sets--the fact that two sets have 
the same cardinality doesn't imply they must have the same measure. 
For example, any continuous probability distribution used in 
statistics (the bell curve, for example) can be used to assign a 
measure to an arbitrary finite interval (which necessarily contains an 
infinite number of points), the measure just being the area under the 
curve over that interval.


Jesse



Jesse I agree with you from the third person perspective. You can only 
take a measure of infinite sets when you have more then one set . In 
other words you need at least two sets so you can compare them. However 
in the case of first person perspective, the observer has only his own 
set. All he has is the cardinality of the set and he has only one set. 
No other set to compare it to. The cardinality is the same for all first 
person observers.


George



Re: Quantum Immortality and Information Flow

2005-12-13 Thread Jesse Mazer


George Levy wrote:



Jesse Mazer wrote:


George Levy:


Bruno Marchal wrote:

we are conscious only because we belong to a continuum of infinite 
never ending stories ...
...that's what the lobian machine's guardian angel  G* says about 
that: true and strictly unbelievable.


Bruno
Since you agree that the number of histories is on a continuum, you must 
accept that no matter how large or small a segment of the continuum is 
considered, the number of histories is the same. Hence measure is the 
same for any observer.



The whole concept of measure is based on assigning different 
probabilities to different infinite sets--the fact that two sets have the 
same cardinality doesn't imply they must have the same measure. For 
example, any continuous probability distribution used in statistics (the 
bell curve, for example) can be used to assign a measure to an arbitrary 
finite interval (which necessarily contains an infinite number of points), 
the measure just being the area under the curve over that interval.


Jesse



Jesse I agree with you from the third person perspective. You can only take 
a measure of infinite sets when you have more then one set . In other words 
you need at least two sets so you can compare them. However in the case of 
first person perspective, the observer has only his own set. All he has is 
the cardinality of the set and he has only one set. No other set to compare 
it to. The cardinality is the same for all first person observers.


George



But if you have one set with an infinite number of elements, you can assign 
different measures to different infinite subsets of that set. And weren't 
you talking about an infinite number of histories above?


Jesse




Re: Quantum Immortality and Information Flow

2005-12-13 Thread George Levy

Jesse Mazer wrote:



George Levy wrote:



Jesse Mazer wrote:


George Levy:


Bruno Marchal wrote:

we are conscious only because we belong to a continuum of 
infinite never ending stories ...
...that's what the lobian machine's guardian angel  G* says 
about that: true and strictly unbelievable.



Bruno
Since you agree that the number of histories is on a continuum, you 
must accept that no matter how large or small a segment of the 
continuum is considered, the number of histories is the same. Hence 
measure is the same for any observer.




The whole concept of measure is based on assigning different 
probabilities to different infinite sets--the fact that two sets 
have the same cardinality doesn't imply they must have the same 
measure. For example, any continuous probability distribution used 
in statistics (the bell curve, for example) can be used to assign a 
measure to an arbitrary finite interval (which necessarily contains 
an infinite number of points), the measure just being the area under 
the curve over that interval.


Jesse




Jesse I agree with you from the third person perspective. You can 
only take a measure of infinite sets when you have more then one set 
. In other words you need at least two sets so you can compare them. 
However in the case of first person perspective, the observer has 
only his own set. All he has is the cardinality of the set and he has 
only one set. No other set to compare it to. The cardinality is the 
same for all first person observers.


George



But if you have one set with an infinite number of elements, you can 
assign different measures to different infinite subsets of that set. 
And weren't you talking about an infinite number of histories above?


Jesse


Jesse,
the infinite number of histories refer to the continuum of histories. 
The first person observer can only perceive through his own experiments 
that physics in his own world, provides a infinite number of histories 
as large as the continuum.  All he knows is that his own history  is 
embedded in a continuum of histories.


George



Re: Quantum Immortality and Information Flow

2005-12-13 Thread Jesse Mazer

George Levy wrote:


Jesse,
the infinite number of histories refer to the continuum of histories. The 
first person observer can only perceive through his own experiments that 
physics in his own world, provides a infinite number of histories as large 
as the continuum.  All he knows is that his own history  is embedded in a 
continuum of histories.


George



I don't understand why he can't say there's a measure on that continuum, 
though. And surely an infinite number of histories can be broken into a 
finite number of subsets based on a single criterion, like the set of all 
future histories in which the next roll of this die will come up 6 and the 
set of all future histories in which the next roll of this die will not come 
up 6, with different measures assigned to the subsets (in this case, one 
would ordinarily assume the first subset has measure 1/6 and the second has 
measure 5/6).


Also, I'm still confused about your original argument:

Since you agree that the number of histories is on a continuum, you must 
accept that no matter how large or small a segment of the continuum is 
considered, the number of histories is the same. Hence measure is the same 
for any observer.


What is the number of histories that is the same here? Weren't you saying 
the number is infinity? And do you agree that in general it is not correct 
to say that because two sets contain an infinite number of elements, that 
means their measure must be the same?


Jesse




Re: Quantum Immortality and Information Flow

2005-12-12 Thread Bruno Marchal


Le 11-déc.-05, à 11:58, Stathis Papaioannou a écrit :

You find yourself alone in a room with a light that alternates 
red/green with a period of one minute. A letter in the room informs 
you that every other minute, 10^100 copies of you are created and run 
in parallel for one minute, then shut down. The transition between the 
two states (low measure/ high measure) corresponds with the change in 
the colour of the light, and you task is to guess which colour 
corresponds to which state.


The problem is, whether the light is red or green, you could argue 
that you are vastly more likely to be sampled from the 10^100 group. 
You might decide to say that *both* red and green correspond to the 
larger group, because if you say this 10^100 copies in the multiverse 
will be correct and only one copy will be wrong. But clearly, this 
tyranny of the majority strategy brings you no closer to the truth. If 
you tossed a coin, at least you would have a 1/2 chance of being 
right.



Yes but this is due to the shut down. (if I got correctly your 
experiment).The probabilities can be taken only on the stories without 
dead-ends, and I guess you consider the shut down as sort of absolute 
annihilation.
I know this is hard to believe, but apparently we are conscious only 
because we belong to a continuum of infinite never ending stories ...


I don't believe this, but then that's what the lobian machine's 
guardian angel  G* says about that: true and strictly unbelievable.


Do you accept that your argument won't go through if the shut down are 
deleted?


Bruno

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




Re: Quantum Immortality and Information Flow

2005-12-12 Thread daddycaylor

Bruno wrote:

Le 11-déc.-05, à 11:58, Stathis Papaioannou a écrit : 
 

You find yourself alone in a room with a light that alternates
red/green with a period of one minute. A letter in the room informs
you that every other minute, 10^100 copies of you are created and run
in parallel for one minute, then shut down. The transition between 

the

two states (low measure/ high measure) corresponds with the change in
the colour of the light, and you task is to guess which colour
corresponds to which state. 
 
The problem is, whether the light is red or green, you could argue
that you are vastly more likely to be sampled from the 10^100 group.
You might decide to say that *both* red and green correspond to the
larger group, because if you say this 10^100 copies in the multiverse
will be correct and only one copy will be wrong. But clearly, this
tyranny of the majority strategy brings you no closer to the truth. 

If

you tossed a coin, at least you would have a 1/2 chance of being
right. 

 
Yes but this is due to the shut down. (if I got correctly your 
experiment).The probabilities can be taken only on the stories without 
dead-ends, and I guess you consider the shut down as sort of absolute 
annihilation. 
I know this is hard to believe, but apparently we are conscious only 
because we belong to a continuum of infinite never ending stories ... 

 
I don't believe this, but then that's what the lobian machine's 

guardian angel G* says about that: true and strictly unbelievable. 


Do you accept that your argument won't go through if the shut down 

are deleted? 


Bruno 

http://iridia.ulb.ac.be/~marchal/ 


In response to Stathis' thought experiment, to speak of an experiment 
being set up in a certain way is to base probabilities on an 
irrelevant subset of the whole, at least if the multiverse hypothesis 
is true.  In the Plenitude, there are an additional 10^100 copies still 
existing, when you say that 10^100 copies are being shut-down.  Talking 
about these additional 10^100 copies is just as consistent as talking 
about the original 10^100 copies (even more consistent if you consider 
Bruno's statement about cul-de-sacs.


In the Plenitude, everything washes out to zero.  And Bruno, I would 
even say that all consistent histories wash out to zero.
Bruno, I've been following your posts about Kripke semantics and have 
done the exercises, including the one about showing that you need a 
symmetrical accessibility relation to have LASE.  However, my initial 
reaction still is that choosing a particular modal logic is scary to 
me, sending up red flags about hidden assumptions that are being made 
in the process.  But I will continue to follow you as you present your 
case.


Earlier Stathis wrote:
Bruno: OK but with comp I have argued that OMs are not primitive but 
are generated, in platonia, by the Universal Dovetailer. A 3- OM is 
just an UD-accessible state, and the 1-OMs inherit relative 
probabilities from the computer science theoretical structuring of the 
3-OMs.


Are OMs directly generated by the UD, or does the UD generate the 
physical (apparently) universe, which leads to the evolution of 
conscious beings, who then give rise to OMs?


Stathis Papaioannou


It's interesting that symmetry (Bruno's requirement for LASE) has come 
up lately, because Stathis' question seems to be what we are all 
wondering.  That's the bottom line of multiverse theories:  Where does 
the symmetry breaking come from?  I maintain still that it can't come 
from the multiverse itself.  Even considering only consistent 
histories, there is no asymmetry to be found.  I maintain that it needs 
to come from outside the multiverse, which is something that we cannot 
explain.


Tom Caylor




Re: Quantum Immortality and Information Flow

2005-12-12 Thread George Levy






Stathis Papaioannou wrote:

In addition to the above arguments, consider the problem
from the point of view of the subject. If multiple copies of a person
are created and run in parallel for a period, what difference does this
make to his experience? It seems to me that there is no test or
experiment the person could do which would allow him to determine if he
is living in a period of high measure or low measure. If an OM is the
smallest discernible unit of conscious experience, it therefore seems
reasonable to treat multiple instantiations of the same OM as one OM.


Yes Stathis, I agree with you completely.


Bruno wrote:
And this already comes from the fact that the
"indistinguishabilitty/distinguishabilitty" crux is itself relative.
By loosing memory something distinguishable can become
indistinguishable, augmenting the class of (normal) self-consistent
extensions. 


Bruno, I find this question extremely difficult. Is
indistinguishability established at the physical level or at the
psychological level? If we say it is established at the psychological
level, then even mental errors ( ie.6+7=11) count in defining a whole
world. This is the ultimate in relativism. I can find reasons to go
either way. (Ultimately Undecided?)

Then I am open that from the 1 point of view, fusion
increases
measure, duplication decreases measure; although from the 3 pov it is
the contrary. 


I do not agree with you on this point Bruno.
>From the one person point of view measures remains constant just like
the speed of light, the mass of an electron, or the number of points in
a line 1 meter long or 1 kilometer long. (the number of points in a
continuum is always the same no matter what the length of the line is).
The one person always observes a continuum in the number of
opportunities available to him no matter what his past history is.
>From the third person point of view, it makes sense to consider ratios
in measures, just like it makes sense to take ratios of line segments
of different lengths. 

George




Re: Quantum Immortality and Information Flow

2005-12-12 Thread Stathis Papaioannou
From the third person perspective, the annihilation of the 10^100 copies 
could be seen as 10^100 dead ends. (In fact, when I originally proposed this 
experiment, Hal Finney thought it represented the ultimate in mass murder.) 
If I were one of the 10^100, however, I wouldn't be worried in the slightest 
about the prospect of dying, because as long as at least one copy survives, 
this guarantees that I survive. This may go again intuition, but if you give 
up the notion of an immaterial soul, there is no reason why there should be 
a one to one relationship between earlier and later versions of a person.


Stathis Papaioannou


Le 11-déc.-05, à 11:58, Stathis Papaioannou a écrit :

You find yourself alone in a room with a light that alternates red/green 
with a period of one minute. A letter in the room informs you that every 
other minute, 10^100 copies of you are created and run in parallel for one 
minute, then shut down. The transition between the two states (low 
measure/ high measure) corresponds with the change in the colour of the 
light, and you task is to guess which colour corresponds to which state.


The problem is, whether the light is red or green, you could argue that 
you are vastly more likely to be sampled from the 10^100 group. You might 
decide to say that *both* red and green correspond to the larger group, 
because if you say this 10^100 copies in the multiverse will be correct 
and only one copy will be wrong. But clearly, this tyranny of the majority 
strategy brings you no closer to the truth. If you tossed a coin, at least 
you would have a 1/2 chance of being right.



Yes but this is due to the shut down. (if I got correctly your 
experiment).The probabilities can be taken only on the stories without 
dead-ends, and I guess you consider the shut down as sort of absolute 
annihilation.
I know this is hard to believe, but apparently we are conscious only 
because we belong to a continuum of infinite never ending stories ...


I don't believe this, but then that's what the lobian machine's guardian 
angel  G* says about that: true and strictly unbelievable.


Do you accept that your argument won't go through if the shut down are 
deleted?


Bruno

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



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Re: Quantum Immortality and Information Flow

2005-12-12 Thread Stathis Papaioannou

Tom Caylor writes:

In response to Stathis' thought experiment, to speak of an experiment being 
set up in a certain way is to base probabilities on an irrelevant 
subset of the whole, at least if the multiverse hypothesis is true.  In the 
Plenitude, there are an additional 10^100 copies still existing, when you 
say that 10^100 copies are being shut-down.  Talking about these additional 
10^100 copies is just as consistent as talking about the original 10^100 
copies (even more consistent if you consider Bruno's statement about 
cul-de-sacs.


In the Plenitude, everything washes out to zero.  And Bruno, I would even 
say that all consistent histories wash out to zero.


Doesn't this ignore the concept of measure in the multiverse? If I buy a 
lottery ticket there are an infinite number of versions of me who win and an 
infinite number of versions who lose, but in some sense there have to be 
more losers than winners, which is why I don't buy lottery tickets.


Stathis Papaioannou

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http://ninemsn.realestate.com.au




Re: Quantum Immortality and Information Flow

2005-12-11 Thread Stathis Papaioannou

Bruno Marchal writes:


Le 10-déc.-05, à 13:24, Stathis Papaioannou a écrit :

In addition to the above arguments, consider the problem from the point of 
view of the subject. If multiple copies of a person are created and run in 
parallel for a period, what difference does this make to his experience? 
It seems to me that there is no test or experiment the person could do 
which would allow him to determine if he is living in a period of high 
measure or low measure.



To determine this with certainty? I agree with you in that case. But we can 
make sure bets.


Take the iterated self-duplication (thought) experiment: You are read,  
cut and then pasted  in two identical rooms except one has 1 drawn on 
the wall where the other has 0.

Then each of you do it again and again.
After 64 duplications you stop. A vast majority among  the 2^64 yous will 
confirms they bet on their normality. Normal experience here is guarantied 
by the incompressible information of most bits sequences (provable by a 
simple combinatorial analysis).
This is equivalent of betting the halving of the  intensity of a beam of x 
polarized photons going through a y analyser, with Everett QM.


What I meant above was that the presence of parallel copies per se cannot 
directly change the quality of the first person experience of any of the 
copies. It may be possible to infer the presence of other copies by indirect 
means; for example, in a closed system a high measure period may be 
characterised by faster oxygen consumption.


I'm not sure what you mean by [a] vast majority among  the 2^64 yous will 
confirms they bet on their normality, but I'm guessing that you are 
referring to the idea that if you bet on being sampled from high measure 
group rather than the low measure group, you are more likely to be right. 
This method has its problems. Consider this thought experiment which I 
proposed a few months ago:


You find yourself alone in a room with a light that alternates red/green 
with a period of one minute. A letter in the room informs you that every 
other minute, 10^100 copies of you are created and run in parallel for one 
minute, then shut down. The transition between the two states (low measure/ 
high measure) corresponds with the change in the colour of the light, and 
you task is to guess which colour corresponds to which state.


The problem is, whether the light is red or green, you could argue that you 
are vastly more likely to be sampled from the 10^100 group. You might decide 
to say that *both* red and green correspond to the larger group, because if 
you say this 10^100 copies in the multiverse will be correct and only one 
copy will be wrong. But clearly, this tyranny of the majority strategy 
brings you no closer to the truth. If you tossed a coin, at least you would 
have a 1/2 chance of being right.


If an OM is the smallest discernible unit of conscious experience, it 
therefore seems reasonable to treat multiple instantiations of the same OM 
as one OM.



OK but with comp I have argued that OMs are not primitive but are 
generated, in platonia, by the Universal Dovetailer. A 3- OM is just an 
UD-accessible state, and the 1-OMs inherit relative probabilities from the 
computer science theoretical structuring of the 3-OMs.


It is the 1 3 person distinction which forces, I think, the relativity or 
conditionality of the measure. There is no a priori means to know if we 
are, just now, in a Harry Potter (abnormally informative) type of OM, but 
we can always bet our next OMs will belong to the set of their most normal 
continuators (probably the product of long (deep) computations with 
stability on dovetailing on the reals or noise).


Are OMs directly generated by the UD, or does the UD generate the physical 
(apparently) universe, which leads to the evolution of conscious beings, who 
then give rise to OMs?


Stathis Papaioannou

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Re: Quantum Immortality and Information Flow

2005-12-10 Thread Stathis Papaioannou

George Levy writes:


Hi Quentin, Stathis, Bruno

It all depends how you see the plenitude, OMs and the branching. Is 
consciousness like a traveller in a network of roads traversing the 
plenitude, some roads branching some roads merging?


If yes then you could have several independent consciousness occupying the 
same spot, or the same OM. Then their measure at that spot is their sum. 
This approach is a third person point of view and it leads to the concept 
of absolute measure.


If you see consiousness as the road itself, then measure is not increased 
after a merge and does not decrease after a split. An OM is just a point on 
the road. If the road turns unexpectedly to avoids an obstacle (like 
quantum suicide or just plain death), then consiousness will just move on 
into a direction which has a low 3-rd person probability but unity first 
person probability. Viewing consciousness as a network of roads is a first 
person point of view and it leads to the concept of relative measure: 
Measure is always 1 where you are. From a given point you may reach many 
points - Then measure increases with respect to that point. Or reversibly, 
from many points you may reach only one point. Then measure decreases.


Bruno writes:

   neither elimination of information, nor duplication of 
information.


The crux of the matter is the concept of indistinguishability: whether you 
consider two identical persons (OMs) occupying two identical universes the 
same person (point on the road). It is clear that if you consider the 
problem from the information angle, then duplication of information does 
not increase the measure of that information. This would support the 
relative interpretation of measure.



In addition to the above arguments, consider the problem from the point of 
view of the subject. If multiple copies of a person are created and run in 
parallel for a period, what difference does this make to his experience? It 
seems to me that there is no test or experiment the person could do which 
would allow him to determine if he is living in a period of high measure or 
low measure. If an OM is the smallest discernible unit of conscious 
experience, it therefore seems reasonable to treat multiple instantiations 
of the same OM as one OM.



Stathis Papaioannou

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Re: Quantum Immortality and Information Flow

2005-12-10 Thread Bruno Marchal


Le 10-déc.-05, à 13:24, Stathis Papaioannou a écrit :

In addition to the above arguments, consider the problem from the 
point of view of the subject. If multiple copies of a person are 
created and run in parallel for a period, what difference does this 
make to his experience? It seems to me that there is no test or 
experiment the person could do which would allow him to determine if 
he is living in a period of high measure or low measure.



To determine this with certainty? I agree with you in that case. But we 
can make sure bets.


Take the iterated self-duplication (thought) experiment: You are 
read,  cut and then pasted  in two identical rooms except one has 
1 drawn on the wall where the other has 0.

Then each of you do it again and again.
After 64 duplications you stop. A vast majority among  the 2^64 yous 
will confirms they bet on their normality. Normal experience here is 
guarantied by the incompressible information of most bits sequences 
(provable by a simple combinatorial analysis).
This is equivalent of betting the halving of the  intensity of a beam 
of x polarized photons going through a y analyser, with Everett QM.




If an OM is the smallest discernible unit of conscious experience, it 
therefore seems reasonable to treat multiple instantiations of the 
same OM as one OM.



OK but with comp I have argued that OMs are not primitive but are 
generated, in platonia, by the Universal Dovetailer. A 3- OM is just 
an UD-accessible state, and the 1-OMs inherit relative probabilities 
from the computer science theoretical structuring of the 3-OMs.


It is the 1 3 person distinction which forces, I think, the relativity 
or conditionality of the measure. There is no a priori means to know if 
we are, just now, in a Harry Potter (abnormally informative) type of 
OM, but we can always bet our next OMs will belong to the set of their 
most normal continuators (probably the product of long (deep) 
computations with stability on dovetailing on the reals or noise).


Bruno



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




Re: Quantum Immortality and Information Flow

2005-12-10 Thread Bruno Marchal

Le 09-déc.-05, à 22:44, George Levy a écrit :

The crux of the matter is the concept of indistinguishability: whether you consider two identical persons (OMs) occupying two identical universes the same person (point on the road). It is clear that if you consider the problem from the information angle, then duplication of information does not increase the measure of that information. This would support the relative interpretation of measure.

Yes. And this already comes from the fact that the indistinguishabilitty/distinguishabilitty crux is itself relative. By loosing memory something distinguishable can become indistinguishable, augmenting the class of (normal) self-consistent extensions.

Then I am open that from the 1 point of view, fusion increases measure, duplication decreases measure; although from the 3 pov it is the contrary.

Bruno

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


Re: Quantum Immortality and Information Flow

2005-12-09 Thread Bruno Marchal

Le 08-déc.-05, à 22:21, George Levy a écrit :


Bruno Marchal wrote:
Le 05-déc.-05, à 02:46, Saibal Mitra a écrit :


I still think that if you double everything and then annihilate only the
doubled person, the probability will be 1.



Actually I agree with this.



So far we have been talking about splitting universes and people. Let's consider the case where two branches of the universe merge. 



Of course this is the an hard and interesting question ... I would say that Everett, Deutsch, Hartle somehow answer it in the quantum realm. I would say that empirically or apparently, at the bottom there is neither elimination of information, nor duplication of information.
Irreversibility and non cloning.
I believe comp entails this too. Got evidence from the interview with the Lobian Machine, but also from some intuitive way to put (first person) measure on the computational histories generated by the UD.





In other words, two different paths eventually happen to become identical - 

At the bottom I don't think this can happens. Like Deutch I think that both bifurcation and fusion are really differentiation and dedifferentiation by *apparent* lack of memory.

Remember  Y = II   If you bifurcate I think you just grow the measure on your past. If you fuse consistently you don't change the measure. To be sure I have also different arguments in favor of an increase of measure when you fuse (loosing memory makes greater your possible histories, like substracting equations in a system of equations augments the possible number of solutions (the Galois connection).
All this is very difficult, that I think we should take benefit of Godel, Lob, Solovay and the discovery of the (modal) logic of self-reference G and G* to ask the opinion of a universal machine ...



Of course when this happens all their branching futures also become identical. 

This is not so obvious. You should define a notion of identity for the branches, path, etc.



Would you say that such a double branch has double the measure of a single branch even though the two branches are totally indistinguishable? How can you possibly assert that any branch is single, double, or a bundle composed of any number of identical individual branches?

Indeed, how?  And from which point of view?


Bruno

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


Re: Quantum Immortality and Information Flow

2005-12-09 Thread George Levy




Hi Quentin, Stathis, Bruno

Quentin Anciaux wrote:

  Hi Georges,

if you start from OMs as basic, then a branch is a set of  OMs (only 
"consistent"/ordered set ?). Then it means a branch is unique. Some part of 
different branches could overlap, but as I don't understand what could be an 
absolute measure (meaning it never change and is fixed forever) between all 
branches, I don't see how to assert the measure of a branch... Also viewing 
from this point each 1st pov "lives" in its own branch (as a branch is an 
ordered set of OMs which in turn is associated to a 1st person).

  

Hi Quentin, Stathis, Bruno

It all depends how you see the plenitude, OMs and the branching. Is
consciousness like a traveller in a network of roads traversing the
plenitude, some roads branching some roads merging?

If yes then you could have several independent consciousness occupying
the same spot, or the same OM. Then their measure at that spot is their
sum. This approach is a third person point of view and it leads to the
concept of absolute measure.

If you see consiousness as the road itself, then measure is not
increased after a merge and does not decrease after a split. An OM is
just a point on the road. If the road turns unexpectedly to avoids an
obstacle (like quantum suicide or just plain death), then consiousness
will just move on into a direction which has a low 3-rd person
probability but unity first person probability. Viewing consciousness
as a network of roads is a first person point of view and it leads to
the concept of relative measure: Measure is always 1 where you are.
>From a given point you may reach many points - Then measure increases
with respect to that point. Or reversibly, from many points you may
reach only one point. Then measure decreases.

Bruno writes:

        neither elimination of information, nor duplication of
information.


The crux of the matter is the concept of indistinguishability: whether
you consider two identical persons (OMs) occupying two identical
universes the same person (point on the road). It is clear that if you
consider the problem from the information angle, then duplication of
information does not increase the measure of that information. This
would support the relative interpretation of measure.

George




  Quentin


Le Jeudi 8 Décembre 2005 22:21, George Levy a écrit :
  
  
Bruno Marchal wrote:


  Le 05-déc.-05, à 02:46, Saibal Mitra a écrit :
  
  
I still think that if you double everything and then annihilate only the
doubled person, the probability will be 1.

  
  Actually I agree with this.
  

So far we have been talking about splitting universes and people. Let's
consider the case where two branches of the universe merge. In other
words, two different paths eventually happen to become identical - Of
course when this happens all their branching futures also become
identical. Would you say that such a double branch has double the
measure of a single branch even though the two branches are totally
indistinguishable? How can you possibly assert that any branch is
single, double, or a bundle composed of any number of identical
individual branches?

George

  
  


  






Re: Quantum Immortality and Information Flow

2005-12-08 Thread George Levy




Bruno Marchal wrote:

Le 05-dc.-05,  02:46, Saibal Mitra a crit :
  
  
  
  I still think that if you double everything
and then annihilate only the

doubled person, the probability will be 1.

  
  
  
  
Actually I agree with this.
  
  
  


So far we have been talking about splitting universes and people. Let's
consider the case where two branches of the universe merge. In
other words, two different paths eventually happen to become identical
- Of course when this happens all their branching futures also become
identical. Would you say that such a double branch has double the
measure of a single branch even though the two branches are totally
indistinguishable? How can you possibly assert that any branch is
single, double, or a bundle composed of any number of identical
individual branches?

George 




Re: Quantum Immortality and Information Flow

2005-12-07 Thread Bruno Marchal


Le 05-déc.-05, à 02:46, Saibal Mitra a écrit :


I still think that if you double everything and then annihilate only 
the

doubled person, the probability will be 1.




Actually I agree with this.





This is simply a consequence of
using the absolute measure.




Ah ? I am not sure this makes sense. If this makes sense, then the 
Absolute Measurer and the Relative one are closer than I was used to 
think.








The idea is that the future is ''already out
there''.




Again I agree, but I would say the 2^aleph_0 futures are already out 
there.  That's why we need a measure. I could say that the 
mathematical shape of that measure should be absolute (the same in all 
the worlds of the multiverse). The value of the measure with respect to 
the choice of some experiment is relative. Would you agree?







So, the correct picture is not that suddenly the plenitude is made
larger because a copy of the person plus (part of) his universe is 
appended
to the plenitude. The plenitude itself is a timeless entity, 
containing all
possible states. If someone wants to carry out a duplication 
experiment then

the results of that are ''already'' present in the plenitude.



I agree if you are talking about the 3-plenitude. For the 1-plenitude, 
the question is more delicate.
(G* can show that the 1 and 3 notions of plenitude are the same, but 
from the machine point of view (either 1 or 3 view) this in not the 
case at all: the 1-plenitude will look much vaster than the 
3-plenitude. This is akin to the Skolem paradox in axiomatic set 
theory, but also to some carrolian or monthy-python like fantasies 
where some place look tiny as seen from outside and very big from 
inside :)





When death can be ignored then the apparent time evolution can be 
described
by a relative measure which is given as the ratio of absolute measures 
taken
before and after an experiment (as pointed out by George Levy in a 
previous

reply).



Yes but as far as I remember older posts by George Levy, we need also 
to take into account some fusion of histories, by amnesy or quantum 
erasure, and this prohibits trust in the use of intuitive 
probabilities. Then the interview of the Universal machine explains 
somehow why things are counter-intuitive there (self-reference 
limitations).






Note that the locality of the laws of physics imply that you can
never directly experience the past.



Yes but then you should make clear if you assume the laws of physics 
just for illustration or as a fundamental hypothesis. From you other 
recent post I guess you don't assume the physical laws, just the 
algorithm (and I add the mathematical execution of those algorithm in 
platonia. OK?







So, if you measure the z-component of a
spin polarized in the x-direction, you will find yourself in a state 
where

you have measured, say, spin up, while you have a memory of how you
prepaired the spin of the particle, some time before you made the
measurement. One thus has to distinguish between the three states:

S1: the experimenter prepaires the spin of the particle

S2: the experimenter finds spin up while having the memory of being in 
S1


S3: the experimenter finds spin down while having the memory of being 
in S1


These three states are ''timeless'' elements of the plenitude. They 
have
their own intrinsic measures. I challenge people on this list to 
explain why
this is not the case. If you have a plenitude you have everything. So, 
S1,

S2 and S3 are just ''out there''.




OK.





The measure of S2  and S3 are half that of
S1. The probability of being in either S2 or S3 is thus the same as 
being in

S1.



OK (relatively). 3-point-of- view talk.




But if measuring spin down leads to instant death, then the probability
of being alive after the experiment is half that of being alive before 
the

experiment.



Except that death has no 1-meaning, and should not be taken into 
account for evaluating a probability question. Here too George Levy 
argued some time ago that, strictly speaking the probability to find 
oneself 1-alive is always 1. But here too it is a little delicate 
because it is a typical pure theological truth, it belongs to G* \ G.


I recall G formalizes correctly and completely what sound machines can 
prove about themselves, and that G* formalizes correctly and completely 
what is true about the sound machine, but not necessarily provable 
(that's mainly Solovay theorem). G* \ G literally  axiomatizes what 
sound machines can correctly hope about themselves.


Your post makes me doubt the difference between Absolutist and 
Relativist, about measure, is less big than I was used to think.


Bruno

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



Re: Quantum Immortality and Information Flow

2005-12-07 Thread Bruno Marchal


Le 03-déc.-05, à 11:12, Stathis Papaioannou a écrit :


Bruno Marchal writes:


Le 01-déc.-05, à 07:17, Stathis Papaioannou a écrit :

Why does an OM need to contain so much information to link it to 
other OMs making up a person?  [the complete message is below].



I am not sure I understand. Are you saying, like Saibal Mitra, that 
OMs (Observer-Moments) are not related? How, in this case, would you 
interpret your own talk about next observer moment (those which 
could be dead end)?
Is there not a confusion between the idea of physicalist (causal) 
view of the relation between OMs (which, as Brent meeker said should 
be explained from a more primitive (mathematical, immaterial, not 
causal, ...)  notion of OM, with those very (more primitive) OMs.
Are you assuming some notion of multiverse richer than (or just 
different from) a notion of multi-OMs?


In our ordinary experience, the OMs making up an individual's stream 
of consciousness are causally related by virtue of the fact that that 
they occur inside the same brain. If we consider thought experiments 
involving teleportation or mind uploading, again the sequential OMs 
are causally related due to transfer of the relevant brain pattern (or 
whatever) information. However, this information tranfer is not 
actually *necessary* for the OMs to be experienced as moments in the 
same stream of consciousness. Say an observer experiencing OM a1 
enters a teleporter which then causes another observer experiencing OM 
a2 to be created at the receiving station. Then a1 and a2 are 
sequential OMs, constituting a stream of consciousness a1a2 sampled 
from the life of an individual. If this is so, then if a1 occurs 
anywhere in the multiverse, and a2 occurs anywhere else, the same 
stream of consciousness a1a2 should be experienced - even if a1 and a2 
occur completely at random, with no causal link between them.



No causal link. OK. But there is an arithmetical or 
computer-science-theoretical link. This includes memories, consistency 
conditions, etc.






I am agnostic regarding the question of whether OMs are primitive or 
derivative. The world could be as it appears: the physical universe 
(whatever that means) gives rise to certain special physical processes 
which result in moments of conscious experience, and those moments 
which are related through being the product of circumscribed subsets 
of physical processes constitute a stream of consciousness in an 
individual life. On the other hand, in a world where exactly the same 
OMs as postulated in the previous sentence exist, but all mixed up and 
not connected to any (or any particular) physical process, exactly the 
same individual streams of consciousness would result.



OK. So why ever postulate a physical world, given that the OMs you 
describe already exist independently of us (in arithmetical platonia), 
and that nobody has ever succeed in explaining what a primitive 
physical world could be, and that nobody has ever succeed in relating 
OMs as lived by people and some putative concrete substantial reality? 
I think that with OCCAM, any notion of computationalist OMs, makes the 
idea of a ontologically primitive physical multiverse useless. (and the 
Olympia/movie-graph makes it senseless, but here I would say that 
remark is off-topic).


Bruno

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




Re: Quantum Immortality and Information Flow (was off-list)

2005-12-07 Thread Bruno Marchal


Hi Stathis,




Hi Bruno,

I replied to the first part of your post earlier, but it took a bit 
more time to digest the rest. For what it is worth, I have included my 
thinking out loud below.




Thanks for replying, and thanks for authorizing me to comment online.






Mhh I know this could look like jargon. Let me give 
easy exercises for anybody following this list.


Let me define a  Multiverse (called also frame by Kripke) as any 
non-empty set  W together with an accessibility relation R defined on 
the set. Elements of that set are called world, by definition, and 
I follow the convention to denote worlds by greek letters (or their 
english transcription: alpha, beta, gamma, delta, eta, epsilon, iota, 
kappa, omega, nu, theta, etc.). R is called the accessibility 
relation.


Is W the entire multiverse, containing everything past, present and 
future, or is it a snapshot of the multiverse at a particular time 
point? If it contains everything, are the elements then snapshots of 
particular worlds at particular times?


Does R operate on W mapping its elements to another set, or does it 
indicate that a particular element of W is related to another element? 
What exactly does accessibility mean in reality? Does it mean a 
world is accessible from my present situation if it is possible that I 
will experience that world in my subjective future? What is and isn't 
accessible in this sense is subject to debate, rather than being 
self-evident.




I totally agree with you. The point of modal logic and their multiverse 
semantics does not consist in closing that debate, but just in giving 
us a tool to manage the subtleties inherent with the subject. As you 
correct yourself below, W is any (non-empty) set, and R is any relation 
mapping some element of W to element(s) of W. One element goes to zero, 
one, or more elements. W cannot be empty, by definition, but R can be.
I am really acting like mathematicians are used to act. I provide a 
very general notion of multiverse: any set with any binary relation 
will do. Only later we will reason to find out which multiverses are 
more interesting than others, for example with respect to the measure 
problem, or the 1-3 distinction problem, or the comp hyp, etc.
At this point anybody should be able to begin a list of all 
multiverses, or at least the finite one ...

The list will be like (with set notation):

{a} with R = empty
{a} with R = {(a,a)}
{a,b} with R = empty
{a,b} with R = {(a,a)}
{a, b} with R = {(b,b)}
{a, b} with R = {(a,a),(b,b)}
{a, b} with R = {(a,a), (a,b), (b,b)}
{a, b} with R = {(a,a) (a, b)}
{a, b} with R = {(a,b)(b,b}}
etc.

I use set notations because I cannot make drawings here, but please 
translate all those description into little drawings, it is much more 
readable. To say R = {(a,a) (a,b)} is the same as saying that aRa and 
aRb, that is (in multiverse terms): the world a can reach the world a, 
and the world a can reach the world b. In a drawing the world are 
points and the relation are arrows from a to b when aRb, etc. OK?
The very nature of the worlds a, b, c is left unspecified, and the 
relation of accessibility R is entirely defined by its graph (its set 
of inputs/outputs).
The multiverse {a} and the multiverse {b} really denote the same 
multiverse if nothing special is said about a and b. Snobbish 
algebraists would say they are isomorphic, and that could be wise at 
some point, but that would be too much at this stage.










So the simplest  example of multiverse is given by the set {alpha} +  
the empty relation (so just one dead end!). Another example is the 
set of natural numbers with the divisibility relation ( n R m iff n 
divide m iff there is a k such that n * k = m).


OK, I think this means R indicates one element in W is related to 
another element in W.




Yes indeed.





Let me define a notion of illuminated multiverse (called model by 
the modal logicians). It is just a Kripke multiverse where we 
associate to each world a value 1 or 0 to each sentence letter. The 
Kripke multiverse is illuminated when a truth value (1 or 0) is 
assigned to each proposition, in each world.
Remember that in (propositional) logic we have sentence letter p, q, 
r, etc.
We also say that p is true in alpha for p has value 1 in alpha (in 
some illuminated multiverse).


To clarify: each world alpha, beta etc. in W contains many 
propositions p, q, r etc., and W is called illuminated when we know 
for each proposition whether it is true (1) or false (0).




Yes, except I prefer to say that a proposition is true at or in a 
world, instead of saying the proposition is in the world.






This confuses me a bit, because I think of physical worlds as 
containing things, not propositions.




Just what I was saying! Except that I am not limiting myself to 
physical worlds.







I suppose you could redefine a world as containing only propositions.




There is a sense to do that, once the multiverse is 

Re: Quantum Immortality and Information Flow (was off-list)

2005-12-07 Thread Brent Meeker

Bruno Marchal wrote:
...

What could this mean in a real world example?






Take W as the set of places in Brussels. Take R to be accessible by 
walking in a finite number of foot steps. Then each places at Brussels 
is accessible from itself, giving that you can access it with zero 
steps, or two steps (forward, backward, ...).


Take W as the set of humans, say that aRb if a can see directly, without 
mirror, the back of b. Then a can access all humans except themselves. R 
is said to be irreflexive.


Another important concrete example, which will help us latter to study 
the modal logic of quantum logic. Take the worlds to be the vector of an 
Hilbert Space (or of the simpler 3-dimensional euclidian space). Say 
that a is accessible to b, i.e. aRb,  if the scalar product of a and b 
is non null (i.e. a and b are not orthogonal). 


These are good illustrative examples, but how do they apply to worlds that just 
consist of propositions?  What is the relation of accessibility in the p,q,r 
world(s)?  Is it negation?


Brent Meeker



Re: Quantum Immortality and Information Flow

2005-12-06 Thread Bruno Marchal


Le 05-déc.-05, à 22:49, Russell Standish a écrit :




On Mon, Dec 05, 2005 at 03:58:20PM +0100, Bruno Marchal wrote:


Well at least this isn't a problem of translation. But I still have
difficulty in understanding why Pp=Bp  -B-p should be translated 
into

English as to bet on p (or for that matter pourquoi on devrait
le traduire par a parier a p)

For me Bp  -B-p is simply a statement of consistency - perhaps what
we mean by mathematical truth.




...

So probability of p (in world alpha) is equal to one is well 
captured
by BpDp (in world alpha).  This means (Kripke-semantically) p is 
true

in all accessible world  there is at least one possible world where
true is false.


...


Tell me if this is clear enough. Euh I hope you agree that To bet on
p can be used for the probability one, of course. If that is the
problem, remember I limit myself to the study of the probability one
and its modal dual probability different from zero.

I must go now and I have not really the time to reread myself, hope I
manage the s correctly. Apology if not. Please ask any question if I
have been unclear.

Bruno


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


Yes - this does make sense. Kripke frames are a good way of explaining
why BpDp captures prob=1 type statements. I'm still not sure bet
on is the correct verb though, as in normal life one bets on things 
with

prob 1 (eg on a horse winning a race). Prob=1 is a sure bet, but I
can't quite think of an appropriate verb.





Well thanks, and sure bet is probably better than my phrasing. It is 
really the particular case of probability one.  I will surely explain 
asap why Quantum Logic can be interpreted as the logic of probability 
one in quantum mechanics. This has been single out by Maria Louisa 
Dalla Chiara, the quantum logician of Florence (Firenze) Italy, but it 
was the main basic motivation of von Neumann when he opened the field 
of quantum logic.


Let me give you the main result (by Goldblatt) connecting quantum logic 
and modal logic. It is a theorem of representation of quantum logic 
into modal logic. There exist a function R translating quantum logic in 
modal logic. R can be described recursively in the following way:


The atomic statement p are interpreted by the quantization(*)  BDp. 
i.e R(p) = BDp

the negative statement ~A is interpreted by B~R(A), i.e, R(~A) = B~R(A)
conjonction: R(A  B) = R(A)  R(B).

Goldblatt proved that MQL proves A iff the modal logic B proves R(A)
MQL is for Minimal Quantum Logic (the result can be extended to the 
standard orthomodular quantum logic).


And B is the logic having as 1) axioms: K, T, and LASE (p - BDp), the 
little abstract Schroedinger equation); 2) inferences rules: Modus 
ponens and Necessitation rule.

(Those who have forget should search LASE in the archive).

Exercise: could someone guess which multiverses (W,R) makes LASE valid 
(true in all worlds for all illumination on the worlds)? Answer: R 
need just to be symmetrical. See why?


More explanation soon. I intend to answer an off-line mail by Stathis 
who asks good questions, asap (not today, probably tomorrow). Later I 
will explain how the translation of the UDA (Universal Dovetailer 
Argument) in the language of a lobian machine gives rise to LASE for 
the probability 1, the sure bets.


Cheers,

Bruno

(*) The term quantization in this setting has been introduced by 
Rawling and Selesnick in a paper where they modelize a quantum NOT with 
the modal logic B. Reference and abstract here: 
http://portal.acm.org/citation.cfm?id=347481.



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




Re: Quantum Immortality and Information Flow

2005-12-05 Thread Russell Standish
On Mon, Dec 05, 2005 at 03:58:20PM +0100, Bruno Marchal wrote:
 
 Well at least this isn't a problem of translation. But I still have
 difficulty in understanding why Pp=Bp  -B-p should be translated into
 English as to bet on p (or for that matter pourquoi on devrait
 le traduire par a parier a p)
 
 For me Bp  -B-p is simply a statement of consistency - perhaps what
 we mean by mathematical truth.
 

...

 So probability of p (in world alpha) is equal to one is well captured 
 by BpDp (in world alpha).  This means (Kripke-semantically) p is true 
 in all accessible world  there is at least one possible world where 
 true is false.

...
 
 Tell me if this is clear enough. Euh I hope you agree that To bet on 
 p can be used for the probability one, of course. If that is the 
 problem, remember I limit myself to the study of the probability one 
 and its modal dual probability different from zero.
 
 I must go now and I have not really the time to reread myself, hope I 
 manage the s correctly. Apology if not. Please ask any question if I 
 have been unclear.
 
 Bruno
 
 
 http://iridia.ulb.ac.be/~marchal/

Yes - this does make sense. Kripke frames are a good way of explaining
why BpDp captures prob=1 type statements. I'm still not sure bet
on is the correct verb though, as in normal life one bets on things with
prob 1 (eg on a horse winning a race). Prob=1 is a sure bet, but I
can't quite think of an appropriate verb.

Cheers

-- 
*PS: A number of people ask me about the attachment to my email, which
is of type application/pgp-signature. Don't worry, it is not a
virus. It is an electronic signature, that may be used to verify this
email came from me if you have PGP or GPG installed. Otherwise, you
may safely ignore this attachment.


A/Prof Russell Standish  Phone 8308 3119 (mobile)
Mathematics0425 253119 ()
UNSW SYDNEY 2052 [EMAIL PROTECTED] 
Australiahttp://parallel.hpc.unsw.edu.au/rks
International prefix  +612, Interstate prefix 02



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Re: Quantum Immortality and Information Flow

2005-12-04 Thread Saibal Mitra
I still think that if you double everything and then annihilate only the
doubled person, the probability will be 1. This is simply a consequence of
using the absolute measure. The idea is that the future is ''already out
there''. So, the correct picture is not that suddenly the plenitude is made
larger because a copy of the person plus (part of) his universe is appended
to the plenitude. The plenitude itself is a timeless entity, containing all
possible states. If someone wants to carry out a duplication experiment then
the results of that are ''already'' present in the plenitude.

When death can be ignored then the apparent time evolution can be described
by a relative measure which is given as the ratio of absolute measures taken
before and after an experiment (as pointed out by George Levy in a previous
reply). Note that the locality of the laws of physics imply that you can
never directly experience the past. So, if you measure the z-component of a
spin polarized in the x-direction, you will find yourself in a state where
you have measured, say, spin up, while you have a memory of how you
prepaired the spin of the particle, some time before you made the
measurement. One thus has to distinguish between the three states:

S1: the experimenter prepaires the spin of the particle

S2: the experimenter finds spin up while having the memory of being in S1

S3: the experimenter finds spin down while having the memory of being in S1

These three states are ''timeless'' elements of the plenitude. They have
their own intrinsic measures. I challenge people on this list to explain why
this is not the case. If you have a plenitude you have everything. So, S1,
S2 and S3 are just ''out there''. The measure of S2  and S3 are half that of
S1. The probability of being in either S2 or S3 is thus the same as being in
S1. But if measuring spin down leads to instant death, then the probability
of being alive after the experiment is half that of being alive before the
experiment.




- Original Message - 
From: Stathis Papaioannou [EMAIL PROTECTED]
To: [EMAIL PROTECTED]; everything-list@eskimo.com
Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED]
Sent: Sunday, December 04, 2005 05:32 AM
Subject: Re: Quantum Immortality and Information Flow



 There is, of course, a difference between being duplicated so that there
are
 multiple copies of you in the one Universe, as in teleportation, and being
 duplicated along with the rest of the Universe as a result of MWI
branching.
 In the former case your relative measure increases and problems will arise
 when it comes to deciding who will get the spouse, house, bank account
etc.
 In the latter case your relative measure stays the same because everything
 else is duplicated along with you and nothing will seem to have changed.
You
 agree that in the teleportation example if your duplicate is
instantaneously
 annihilated the moment he comes into being, you will continue living with
 probability 1, as if the duplication had not taken place. On the other
hand,
 in the MWI branching example, you would argue that if your duplicate in
one
 of the branches is annihilated, then your subjective probability of
survival
 is 1/2.

 Now, suppose that instead of just you the entire Earth, or Galaxy, or
 Universe is duplicated along with you, while as before your duplicate (and
 only he) is annihilated the moment he comes into being on the new Earth
(or
 Galaxy, or Universe). It could be argued that your measure relative to the
 rest of the Universe (or that part of it which is duplicated) has now
 decreased. Is your expectation of survival in this case more like the
 original teleportation example, or more like the MWI branching example?

 Stathis Papaioannou



 Saibal Mitra writes:

 This doubling of the absolute measure is important. In another posting
you
 wrote about being teleported to many places and then being annihilated
 everywhere except at the original place. This won't affect the
probability
 of being alive at the original place. But in a QC experiment where you
have
 many outcomes, all leading to death except one, the probability of
 experiencing that branch is very small.
 
 
 
 
 
 
 - Original Message -
 From: Stathis Papaioannou [EMAIL PROTECTED]
 To: [EMAIL PROTECTED]; everything-list@eskimo.com
 Sent: Saturday, December 03, 2005 11:38 AM
 Subject: Re: Quantum Immortality and Information Flow
 
 
   Well, I did actually intend my example to be analogous to the Tegmark
QS
   experiment. Are you saying that if there is only one world and
magically
 an
   identical, separate world comes into being this is fundamentally
 different
   to what happens in quantum branch splitting? It seems to me that in
both
   cases the relative measure of everything in the world stays the same,
 even
   though in absolute terms there is double of everything.
  
   Stathis Papaioannou
  
  
   Saibal Mitra writes:
  
   Correction, I seem to have misunderstood Statis'  set up. If you
really

Re: Quantum Immortality and Information Flow

2005-12-04 Thread Stathis Papaioannou


I'm perhaps missing something here. In a no-collapse interpretation of QM, 
doesn't everything double every moment? So, if only one of the doubled 
versions of a person is annihilated, doesn't this mean the probability of 
survival is 1?


Although the plenitude is timeless, containing all possible states, we 
self-aware substructures certainly experience the illusion (if you prefer, 
the emergent phenomenon) of time. When I consider which parts of the 
plenitude are of selfish interest to me, I need only consider those parts 
which I perceive to be in my unique present or in my pluripotent future. 
More narrowly, I need only consider those parts which I perceive to be in my 
immediate future - my next conscious moment - since it is only through this 
process, a moment at a time, that potential future experiences become actual 
present experiences, rather than irrelevant side-branches, such as the 
version of me who migrated to New Zealand when I was 5 years old. What this 
means is that when I consider the subjective probability of what will happen 
to me in the next moment, I don't have to think about those versions of me 
which are in the past, in the far future, have turned into George Bush or 
are dead. I could put this differently: as a matter of fact, it is not 
incorrect to say that I will suddenly become 5 years old again, or turn into 
Geoge Bush, since all these states exist timelessly in the plenitude and 
there is no absolute sense in which it can be said that one state becomes 
another state. However, from my selfish point of view, when I consider the 
next moment, all those other states are irrelevant. The only relevant states 
are those which count as my next moment, as normally understood by humans. 
Where there are multiple candidate next moments, the probability that I 
will experience one of them depends on the relative measure of each in the 
plenitude. If there is no candidate next moments at all, then I will die.


Stathis Papaioannou



Saibal Mitra writes:


I still think that if you double everything and then annihilate only the
doubled person, the probability will be 1. This is simply a consequence of
using the absolute measure. The idea is that the future is ''already out
there''. So, the correct picture is not that suddenly the plenitude is made
larger because a copy of the person plus (part of) his universe is appended
to the plenitude. The plenitude itself is a timeless entity, containing all
possible states. If someone wants to carry out a duplication experiment 
then

the results of that are ''already'' present in the plenitude.

When death can be ignored then the apparent time evolution can be described
by a relative measure which is given as the ratio of absolute measures 
taken

before and after an experiment (as pointed out by George Levy in a previous
reply). Note that the locality of the laws of physics imply that you can
never directly experience the past. So, if you measure the z-component of a
spin polarized in the x-direction, you will find yourself in a state where
you have measured, say, spin up, while you have a memory of how you
prepaired the spin of the particle, some time before you made the
measurement. One thus has to distinguish between the three states:

S1: the experimenter prepaires the spin of the particle

S2: the experimenter finds spin up while having the memory of being in S1

S3: the experimenter finds spin down while having the memory of being in S1

These three states are ''timeless'' elements of the plenitude. They have
their own intrinsic measures. I challenge people on this list to explain 
why

this is not the case. If you have a plenitude you have everything. So, S1,
S2 and S3 are just ''out there''. The measure of S2  and S3 are half that 
of
S1. The probability of being in either S2 or S3 is thus the same as being 
in

S1. But if measuring spin down leads to instant death, then the probability
of being alive after the experiment is half that of being alive before the
experiment.


_
Buy now @ Tradingpost.com.au 
http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fad%2Eau%2Edoubleclick%2Enet%2Fclk%3B23850242%3B12217581%3Bw%3Fhttp%3A%2F%2Fwww%2Etradingpost%2Ecom%2Eau%2F%3Freferrer%3DnmsnHMetag_t=11482_r=emaildec05_m=EXT




Re: Quantum Immortality and Information Flow

2005-12-03 Thread Quentin Anciaux
Hi Saibal,

Le Samedi 3 Décembre 2005 02:15, Saibal Mitra a écrit :
 Correction, I seem to have misunderstood Statis'  set up. If you really
 create a new world and then create and kill the person there then the
 probability of survival is 1. This is different from quantum mechanical
 branch splitting.

 To see this, consider first what would have happened had the person not
 been killed. Then his measure would have doubled. But because he is killed
 in one of the two copies of Earth, his measure stays the same. In a quantum
 suicide experiment his measure would be reduced by a factor two.

His measure would be reduced by a factor two relative to what ? Do you mean 
there exists an absolute measure ?

Quentin




Re: Quantum Immortality and Information Flow

2005-12-03 Thread Russell Standish
On Mon, Nov 21, 2005 at 03:39:58PM +0100, Bruno Marchal wrote:
 Observation is implicitly defined here by measurement capable of 
 selecting alternatives on which we are able to bet (or to gamble ?). 
 The french word is parier.
 

Well at least this isn't a problem of translation. But I still have
difficulty in understanding why Pp=Bp  -B-p should be translated into
English as to bet on p (or for that matter pourquoi on devrait
le traduire par a parier a p)

For me Bp  -B-p is simply a statement of consistency - perhaps what
we mean by mathematical truth.

Cheers

-- 
*PS: A number of people ask me about the attachment to my email, which
is of type application/pgp-signature. Don't worry, it is not a
virus. It is an electronic signature, that may be used to verify this
email came from me if you have PGP or GPG installed. Otherwise, you
may safely ignore this attachment.


A/Prof Russell Standish  Phone 8308 3119 (mobile)
Mathematics0425 253119 ()
UNSW SYDNEY 2052 [EMAIL PROTECTED] 
Australiahttp://parallel.hpc.unsw.edu.au/rks
International prefix  +612, Interstate prefix 02



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Re: Quantum Immortality and Information Flow

2005-12-03 Thread Stathis Papaioannou
Well, I did actually intend my example to be analogous to the Tegmark QS 
experiment. Are you saying that if there is only one world and magically an 
identical, separate world comes into being this is fundamentally different 
to what happens in quantum branch splitting? It seems to me that in both 
cases the relative measure of everything in the world stays the same, even 
though in absolute terms there is double of everything.


Stathis Papaioannou


Saibal Mitra writes:


Correction, I seem to have misunderstood Statis'  set up. If you really
create a new world and then create and kill the person there then the
probability of survival is 1. This is different from quantum mechanical
branch splitting.

To see this, consider first what would have happened had the person not 
been
killed. Then his measure would have doubled. But because he is killed in 
one
of the two copies of Earth, his measure stays the same. In a quantum 
suicide

experiment his measure would be reduced by a factor two.



 If on the basis of a coin toss the world splits, and in one branch I am
 instantaneously killed while in the other I continue living, there are
 several possible ways this might be interpreted from the 1st person
 viewpoint:

 (a) Pr(I live) = Pr(I die) = 0.5

 (b) Pr(I live) = 1, Pr(I die) = 0

 (c) Pr(I live) = 0, Pr(I die) = 1


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Re: Quantum Immortality and Information Flow

2005-12-03 Thread Saibal Mitra
This doubling of the absolute measure is important. In another posting you
wrote about being teleported to many places and then being annihilated
everywhere except at the original place. This won't affect the probability
of being alive at the original place. But in a QC experiment where you have
many outcomes, all leading to death except one, the probability of
experiencing that branch is very small.






- Original Message - 
From: Stathis Papaioannou [EMAIL PROTECTED]
To: [EMAIL PROTECTED]; everything-list@eskimo.com
Sent: Saturday, December 03, 2005 11:38 AM
Subject: Re: Quantum Immortality and Information Flow


 Well, I did actually intend my example to be analogous to the Tegmark QS
 experiment. Are you saying that if there is only one world and magically
an
 identical, separate world comes into being this is fundamentally different
 to what happens in quantum branch splitting? It seems to me that in both
 cases the relative measure of everything in the world stays the same, even
 though in absolute terms there is double of everything.

 Stathis Papaioannou


 Saibal Mitra writes:

 Correction, I seem to have misunderstood Statis'  set up. If you really
 create a new world and then create and kill the person there then the
 probability of survival is 1. This is different from quantum mechanical
 branch splitting.
 
 To see this, consider first what would have happened had the person not
 been
 killed. Then his measure would have doubled. But because he is killed in
 one
 of the two copies of Earth, his measure stays the same. In a quantum
 suicide
 experiment his measure would be reduced by a factor two.

   If on the basis of a coin toss the world splits, and in one branch I
am
   instantaneously killed while in the other I continue living, there are
   several possible ways this might be interpreted from the 1st person
   viewpoint:
  
   (a) Pr(I live) = Pr(I die) = 0.5
  
   (b) Pr(I live) = 1, Pr(I die) = 0
  
   (c) Pr(I live) = 0, Pr(I die) = 1

 _
 Buy now @ Tradingpost.com.au

http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fad%2Eau%2Edoubleclick%2Enet%2Fclk%3B23850242%3B12217581%3Bw%3Fhttp%3A%2F%2Fwww%2Etradingpost%2Ecom%2Eau%2F%3Freferrer%3DnmsnHMetag_t=11482_r=emaildec05_m=EXT




Re: Quantum Immortality and Information Flow

2005-12-03 Thread Saibal Mitra
- Original Message - 
From: Brent Meeker [EMAIL PROTECTED]
To: Saibal Mitra [EMAIL PROTECTED]
Sent: Saturday, December 03, 2005 03:06 AM
Subject: Re: Quantum Immortality and Information Flow


 Saibal Mitra wrote:
  - Original Message - 
  From: Brent Meeker [EMAIL PROTECTED]
  To: everything-list@eskimo.com
  Cc: everything-list@eskimo.com
  Sent: Sunday, November 27, 2005 07:41 PM
  Subject: Re: Quantum Immortality and Information Flow
 
 
 
 Saibal Mitra wrote:
 
 - Original Message - 
 From: Jonathan Colvin [EMAIL PROTECTED]
 To: everything-list@eskimo.com
 Sent: Sunday, November 27, 2005 05:49 AM
 Subject: RE: Quantum Immortality and Information Flow
 
 
 
 
 Saibal wrote:
 
 
 The answer must be a) because (and here I disagree with
 Jesse), all that exists is an ensemble of isolated observer
 moments. The future, the past, alternative histories, etc.
 they all exist in a symmetrical way. It don't see how some
 states can be more ''real'' than other states. Of course, the
 universe we experience seems to be real to us while
 alternative universes, or past or future states of this
 universe are not being experienced by us.
 
 
 So, you must think of yourself at any time as being  randomly
 sampled from the set of all possible observer moments.
 
 delurk
 
 I'm not sure how this works. Suppose I consider my state now at time
N
 
 as
 
 
 a random sample of all observer moments. Now, after having typed this
 sentence, I consider my state at time N + 4 seconds. Is this also a
 
 random
 
 
 sample on all observer moments?  I can do the same at now N+10, and
 
 so-on.
 
 
 It seems very unlikely that 3 random samples would coincide so
closely.
 
  So
 
 in what sense are these states randomly sampled?
 
 
 It's a bit like symmetry breaking. You have an ensemble of all possible
 observer moment, but each observer moment can only experience its own
 
  state.
 
 So, the OM samples itself.
 
 There exists an observer moment representing you at N seconds, at N + 4
 seconds and at all possible other states. They all ''just exist'' in
the
 plenitude, as Stathis wrote. The OM  representing you at N + 4 has the
 memory of being the OM at N.
 
 This I find confusing.  How is there memory associated with an obserever
 
  moment?
 
   Is it equivocation on memory?  As an experience, remembering
something
 
  takes
 
 much longer than what I would call a moment.  It may involve a
sequence
 images, words, and emotions.  Of course in a materialist model of the
 
  world the
 
 memories are coded in the physical configuration of your brain, even
when
 
  not
 
 being experienced; but an analysis that takes OM's as fundamental can't
 
  refer to
 
 that kind of memories.
 
 
 
  Well, what really matters is that the laws of physics define a
probability
  distribution over OMs. So, there is no problem thinking of yourself as
being
  sampled randomly from that probability distribution. The length of an OM
  can be taken to be zero. Even if recalling something takes time, at any
time
  you are at a certain point in that process. There exists an OM that
recalls
  going through that sequence, but that is also at a specific moment in
time.

 But you're assuming laws of physics and a physical basis for
consciousness.  I
 thought the idea was to take conscious moments as basic.  I'm fine with
taking
 physics as basic - but then what's the point of talking about observer
moments;
 conscious observations are then some kind of emergent phenomena and
they're
 connected by physical causation.



Yes, but it's a fact that there exists laws of physics. I am of the opinion
that what really exists is an ensemble of algorithms and that the laws of
physics is a consequence of this. Whatever your starting point, you'll end
up with an absolute measure over the set of all OMs.



Re: Quantum Immortality and Information Flow

2005-12-03 Thread Stathis Papaioannou


There is, of course, a difference between being duplicated so that there are 
multiple copies of you in the one Universe, as in teleportation, and being 
duplicated along with the rest of the Universe as a result of MWI branching. 
In the former case your relative measure increases and problems will arise 
when it comes to deciding who will get the spouse, house, bank account etc. 
In the latter case your relative measure stays the same because everything 
else is duplicated along with you and nothing will seem to have changed. You 
agree that in the teleportation example if your duplicate is instantaneously 
annihilated the moment he comes into being, you will continue living with 
probability 1, as if the duplication had not taken place. On the other hand, 
in the MWI branching example, you would argue that if your duplicate in one 
of the branches is annihilated, then your subjective probability of survival 
is 1/2.


Now, suppose that instead of just you the entire Earth, or Galaxy, or 
Universe is duplicated along with you, while as before your duplicate (and 
only he) is annihilated the moment he comes into being on the new Earth (or 
Galaxy, or Universe). It could be argued that your measure relative to the 
rest of the Universe (or that part of it which is duplicated) has now 
decreased. Is your expectation of survival in this case more like the 
original teleportation example, or more like the MWI branching example?


Stathis Papaioannou



Saibal Mitra writes:


This doubling of the absolute measure is important. In another posting you
wrote about being teleported to many places and then being annihilated
everywhere except at the original place. This won't affect the probability
of being alive at the original place. But in a QC experiment where you have
many outcomes, all leading to death except one, the probability of
experiencing that branch is very small.






- Original Message -
From: Stathis Papaioannou [EMAIL PROTECTED]
To: [EMAIL PROTECTED]; everything-list@eskimo.com
Sent: Saturday, December 03, 2005 11:38 AM
Subject: Re: Quantum Immortality and Information Flow


 Well, I did actually intend my example to be analogous to the Tegmark QS
 experiment. Are you saying that if there is only one world and magically
an
 identical, separate world comes into being this is fundamentally 
different

 to what happens in quantum branch splitting? It seems to me that in both
 cases the relative measure of everything in the world stays the same, 
even

 though in absolute terms there is double of everything.

 Stathis Papaioannou


 Saibal Mitra writes:

 Correction, I seem to have misunderstood Statis'  set up. If you really
 create a new world and then create and kill the person there then the
 probability of survival is 1. This is different from quantum mechanical
 branch splitting.
 
 To see this, consider first what would have happened had the person not
 been
 killed. Then his measure would have doubled. But because he is killed 
in

 one
 of the two copies of Earth, his measure stays the same. In a quantum
 suicide
 experiment his measure would be reduced by a factor two.

   If on the basis of a coin toss the world splits, and in one branch I
am
   instantaneously killed while in the other I continue living, there 
are

   several possible ways this might be interpreted from the 1st person
   viewpoint:
  
   (a) Pr(I live) = Pr(I die) = 0.5
  
   (b) Pr(I live) = 1, Pr(I die) = 0
  
   (c) Pr(I live) = 0, Pr(I die) = 1

 _
 Buy now @ Tradingpost.com.au

http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fad%2Eau%2Edoubleclick%2Enet%2Fclk%3B23850242%3B12217581%3Bw%3Fhttp%3A%2F%2Fwww%2Etradingpost%2Ecom%2Eau%2F%3Freferrer%3DnmsnHMetag_t=11482_r=emaildec05_m=EXT




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Re: Quantum Immortality and Information Flow

2005-12-02 Thread Bruno Marchal


Le 01-déc.-05, à 07:17, Stathis Papaioannou a écrit :

Why does an OM need to contain so much information to link it to other 
OMs making up a person?  [the complete message is below].



I am not sure I understand. Are you saying, like Saibal Mitra, that OMs 
(Observer-Moments) are not related? How, in this case, would you 
interpret your own talk about next observer moment (those which could 
be dead end)?
Is there not a confusion between the idea of physicalist (causal) view 
of the relation between OMs (which, as Brent meeker said should be 
explained from a more primitive (mathematical, immaterial, not causal, 
...)  notion of OM, with those very (more primitive) OMs.
Are you assuming some notion of multiverse richer than (or just 
different from) a notion of multi-OMs?


At least, when you interview a sound lobian machine on such questions 
(through the modal logic G), or better when you interview its guardian 
angel (through its modal logic G*), you can understand that the 
ultimate multiverse can reasonably be said not having structure, and 
that multiverse-structures *appear* for each notion of self-referential 
points of view (not necessarily first person pov). The first person pov 
makes the multiverse a temporal structure, the first person plural 
pov makes the multiverse a quantum probability structure.



   ***


Mhh I know this could look like jargon. Let me give easy 
exercises for anybody following this list.


Let me define a  Multiverse (called also frame by Kripke) as any 
non-empty set  W together with an accessibility relation R defined on 
the set. Elements of that set are called world, by definition, and I 
follow the convention to denote worlds by greek letters (or their 
english transcription: alpha, beta, gamma, delta, eta, epsilon, iota, 
kappa, omega, nu, theta, etc.). R is called the accessibility relation.
So the simplest  example of multiverse is given by the set {alpha} +  
the empty relation (so just one dead end!). Another example is the set 
of natural numbers with the divisibility relation ( n R m iff n divide 
m iff there is a k such that n * k = m).



Let me define a notion of illuminated multiverse (called model by the 
modal logicians). It is just a Kripke multiverse where we associate to 
each world a value 1 or 0 to each sentence letter. The Kripke 
multiverse is illuminated when a truth value (1 or 0) is assigned to 
each proposition, in each world.
Remember that in (propositional) logic we have sentence letter p, q, r, 
etc.
We also say that p is true in alpha for p has value 1 in alpha (in some 
illuminated multiverse).



Now Kripke semantics can be given in a very simple way, by just asking 
that,


1) each world obeys to classical logic (that is: if 1 is assigned to p 
in the world alpha, and if 1 is assigned to q in alpha, then 1 is 
assigned to (p  q) in alpha, etc. The etc is just a pointer to the 
usual truth table of classical propositional logic. I have already 
explain this on this list but I can do it again if asked). In 
particular each classical tautologies are true in all worlds, whatver 
the illumination chosen (whatever the truth value of the sentence 
letter are in each world: like (p - p) or (p v ~p), etc.


2) Kripke says that Bp (also written box p, []p, etc.) is true in the 
world alpha if p is true in all worlds beta accessible from alpha. From 
this it follows that Dp (defined as an abbreviation of ~B~p) will be 
true in some world alpha if there is some world beta, accessible from 
alpha, and with p true in the world beta.


Now I will say that a formula A of modal logic is valid in a 
illuminated multiverse (W, R, V)  if A is true in all the worlds of 
that illuminated multiverse.


And I will say that a formula A of modal logic is respected by a 
multiverse (W,R)  if A is valid
in all illuminated multiverse (W, R, V). Or equivalently: A is 
respected in (W,R)  if A is true in all worlds in W and this for all 
illuminations V, i.e. for all assignment of truth value of the 
sentence letters in all worlds.


Last definition: a multiverse (W,R) is said to be reflexive if the 
relation R is reflexive (that is: if for all world in W we have xRx, 
i.e. if each world is accessible to itself by the relation R.


The easy exercise is the following: show that if the multiverse is 
reflexive then the multiverse respects the formula Bp - p.


Slightly less easy: show that the reverse is true: show that if a 
multiverse respects Bp - p, then the multiverse is reflexive.


I would like to know if that exercise *seems* difficult. For those who 
cannot do it, it just means there is a need to refresh some naive set 
theory knowledge, and I will think about a book who can help.


Don't hesitate to answer out of line if you prefer.

Sorry to annoy you with that modal stuff, but we are at a point I could 
no more comment the posts without making nuances which will 

Re: Quantum Immortality and Information Flow

2005-12-02 Thread Saibal Mitra

- Original Message - 
From: Brent Meeker [EMAIL PROTECTED]
To: everything-list@eskimo.com
Cc: everything-list@eskimo.com
Sent: Sunday, November 27, 2005 07:41 PM
Subject: Re: Quantum Immortality and Information Flow


 Saibal Mitra wrote:
  - Original Message - 
  From: Jonathan Colvin [EMAIL PROTECTED]
  To: everything-list@eskimo.com
  Sent: Sunday, November 27, 2005 05:49 AM
  Subject: RE: Quantum Immortality and Information Flow
 
 
 
 Saibal wrote:
 
 The answer must be a) because (and here I disagree with
 Jesse), all that exists is an ensemble of isolated observer
 moments. The future, the past, alternative histories, etc.
 they all exist in a symmetrical way. It don't see how some
 states can be more ''real'' than other states. Of course, the
 universe we experience seems to be real to us while
 alternative universes, or past or future states of this
 universe are not being experienced by us.
 
 
 So, you must think of yourself at any time as being  randomly
 sampled from the set of all possible observer moments.
 
 delurk
 
 I'm not sure how this works. Suppose I consider my state now at time N
 
  as
 
 a random sample of all observer moments. Now, after having typed this
 sentence, I consider my state at time N + 4 seconds. Is this also a
 
  random
 
 sample on all observer moments?  I can do the same at now N+10, and
 
  so-on.
 
 It seems very unlikely that 3 random samples would coincide so closely.
So
 in what sense are these states randomly sampled?
 
 
  It's a bit like symmetry breaking. You have an ensemble of all possible
  observer moment, but each observer moment can only experience its own
state.
  So, the OM samples itself.
 
  There exists an observer moment representing you at N seconds, at N + 4
  seconds and at all possible other states. They all ''just exist'' in the
  plenitude, as Stathis wrote. The OM  representing you at N + 4 has the
  memory of being the OM at N.

 This I find confusing.  How is there memory associated with an obserever
moment?
   Is it equivocation on memory?  As an experience, remembering something
takes
 much longer than what I would call a moment.  It may involve a sequence
 images, words, and emotions.  Of course in a materialist model of the
world the
 memories are coded in the physical configuration of your brain, even when
not
 being experienced; but an analysis that takes OM's as fundamental can't
refer to
 that kind of memories.


Well, what really matters is that the laws of physics define a probability
distribution over OMs. So, there is no problem thinking of yourself as being
sampled randomly from that probability distribution. The length of an OM
can be taken to be zero. Even if recalling something takes time, at any time
you are at a certain point in that process. There exists an OM that recalls
going through that sequence, but that is also at a specific moment in time.



Re: Quantum Immortality and Information Flow

2005-12-02 Thread Saibal Mitra
- Original Message - 
From: Jonathan Colvin [EMAIL PROTECTED]
To: everything-list@eskimo.com
Sent: Sunday, November 27, 2005 10:02 PM
Subject: RE: Quantum Immortality and Information Flow



 Saibal wrote:
The answer must be a) because (and here I disagree with
Jesse), all that exists is an ensemble of isolated observer
moments. The future, the past, alternative histories, etc.
they all exist in a symmetrical way. It don't see how some
states can be more ''real'' than other states. Of course, the
universe we experience seems to be real to us while
alternative universes, or past or future states of this
universe are not being experienced by us.
   
   
So, you must think of yourself at any time as being  randomly
sampled from the set of all possible observer moments.
  
   delurk
  
   I'm not sure how this works. Suppose I consider my state
  now at time N
  as
   a random sample of all observer moments. Now, after having
  typed this
   sentence, I consider my state at time N + 4 seconds. Is
  this also a
  random
   sample on all observer moments?  I can do the same at now
  N+10, and
  so-on.
   It seems very unlikely that 3 random samples would coincide
  so closely. So
   in what sense are these states randomly sampled?
 
  It's a bit like symmetry breaking. You have an ensemble of
  all possible
  observer moment, but each observer moment can only experience
  its own state.
  So, the OM samples itself.
 
  There exists an observer moment representing you at N
  seconds, at N + 4
  seconds and at all possible other states. They all ''just
  exist'' in the
  plenitude, as Stathis wrote. The OM  representing you at N + 4 has the
  memory of being the OM at N. Subjectively the OMs experience
  time evolution,
  even though the plenitude itself doesn't have a time evolution at the
  fundamental level.

 I understand all that, but I still don't see in what sense these OM's are
 randomly sampled.

 Here's a related question. The DDA insists that we must all consider
 ourselves random observers on our reference class, whatever it is (class
of
 all observers is standard). Now, if I am a random observer, and you
(Saibal)
 are a random observer, what are the odds that two observers selected
 randomly from the class of all observers would be discoursing on the same
 mailing list? We can only conclude that one of us can not be random, but
 must have been selected by the other. But did I select you, or did you
 select me? If we select each other, the randomness issue is not resolved.

 Another possibility is, I suppose, to simply *define* randomness as
observer
 self-selection. Perhaps observer self-selection is the only truly random
 phenomenon in the universe (everything else appearing random is merely
 unpredictable). But it is then a purely a first-person phenomenon, and I
can
 not consider anything else in the universe (including *your* observer
 moments) as random.



Yes, I meant ''random'' in the sense of observer self selection. But note
that the laws of physics define, in principle, a probability distribution
over the set over all possible states you can be in. One element of that set
corresponds to you reading this sentence. The probability of this is given
by an integral of the probability of states of the universe that are
consistent with you experiencing this OM. So, you ''integrate out''
everything that is not part of the OM and you are left with the probability
of the OM.



Re: Quantum Immortality and Information Flow

2005-12-02 Thread Saibal Mitra

- Original Message - 
From: Bruno Marchal [EMAIL PROTECTED]
To: Saibal Mitra [EMAIL PROTECTED]
Cc: Jesse Mazer [EMAIL PROTECTED]; Stathis Papaioannou
[EMAIL PROTECTED]; everything-list@eskimo.com
Sent: Monday, November 28, 2005 04:47 PM
Subject: Re: Quantum Immortality and Information Flow



 Le 27-nov.-05, à 02:25, Saibal Mitra a écrit :

  The answer must be a) because (and here I disagree with Jesse), all
  that
  exists is an ensemble of isolated observer moments. The future, the
  past,
  alternative histories, etc.  they all exist in a symmetrical way. It
  don't
  see how some states can be more ''real'' than other states.

 But then how could we ever explain why some states seem to be more
 *near*, or more probable than others from our point of view?

Well, even if you assume ''ordinary'' laws of physics, you can have this
view. Einstein tried to console a friend whose son had died, by saying that
although he isn't alive now, he is ''still'' alive in the past. Relativity
theory threats space and time in more or less symmetrical ways.It doesn't
make any difference if you assume that you are sampled from a probability
distribution (to be calculated from physics) over your experiences.



 Is the choice between Papaioannou's  a, b reflecting(*) the ASSA
 and RSSA difference?

 Recall: ASSA = absolute self-sampling assumption. RSSA = relative
 self-sampling assumption.

 (*) Stathis Papaioannou writes:
  If on the basis of a coin toss the world splits, and in one branch I am
  instantaneously killed while in the other I continue living, there are
  several possible ways this might be interpreted from the 1st person
  viewpoint:
 
  (a) Pr(I live) = Pr(I die) = 0.5
 
  (b) Pr(I live) = 1, Pr(I die) = 0
 
  (c) Pr(I live) = 0, Pr(I die) = 1
 
  Even on this list, there are people who might say (a) above is the case
  rather than (b) or (c).


 Saibal:

  So, you must think of yourself at any time as being  randomly sampled
  from
  the set of all possible observer moments.


 This could make sense in a pure third person perspective, but then it
 is no more a perspective. And, indeed, to predict the result of
 anything I decide to test, I need to take into account relations
 between observer-moments. Let me throw a dice. Are you saying to us
 that to predict the result I need to take into account all
 observer-moments and sample on them in some uniform way. Why should
 people buy lotto-tickets? They could make the big win by their OM being
 sampled on all OMs.
 I'm not saying you are false, but your absolute sample does not
 correspond tour first person experience (including physics) which we
 want to explain. It seems to me.

Well, the probability distribution has to be consistent with physics. In
case of throwing a dice, one should consider the set of OMs that are
experiencing the outcome of the throw.



  To get to answer b) you have to
  redefine your identity so that experiencing having done the experiment
  becomes a necessary part of your identity.

 Not some absolute identity, but memories are part of our relative,
 mundane, identity.



  But this is cheating because you
  wouldn't say that if ''death'' were replaced by a partial memory
  erasure
  such that the experience of having done the experiment were wiped out
  form
  your memory.

 OK, but that is why the experiment is proposed with (absolute) death
 (if that exists) and not with memory erasure. This could change the
 probabilities a lot, and this can admit many different protocol for
 verifying the probability distributions. It is another experiment.
 Perhaps I miss your point.


Yes, that was my point. The probabilities become sensitive to the details of
the set up in a way that I find unphysical. If we just do conventional
quantum measurement of z-component of a spin polarized in the x-direction.
Then, in the MWI, you would say that there exists a world in which an
observer sees spin up and a world in which spin down is experienced.
Strictly speaking the two observers are not identical. Let's now modify the
experiment so that in case of spin down the observer is annihilated and
replaced by some arbitrary person. Then if we choose this person to be
''close'' to the original person then the probabilities are 1/2, but if I
move sufficiently ''far away'' from the person then it should somehow jump
to 1 for the original person.



Re: Quantum Immortality and Information Flow

2005-12-02 Thread Saibal Mitra
Correction, I seem to have misunderstood Statis'  set up. If you really
create a new world and then create and kill the person there then the
probability of survival is 1. This is different from quantum mechanical
branch splitting.

To see this, consider first what would have happened had the person not been
killed. Then his measure would have doubled. But because he is killed in one
of the two copies of Earth, his measure stays the same. In a quantum suicide
experiment his measure would be reduced by a factor two.


- Original Message - 
From: Saibal Mitra [EMAIL PROTECTED]
To: Stathis Papaioannou [EMAIL PROTECTED];
[EMAIL PROTECTED]; Jesse Mazer [EMAIL PROTECTED]
Cc: everything-list@eskimo.com
Sent: Sunday, November 27, 2005 02:25 AM
Subject: Re: Quantum Immortality and Information Flow


 The answer must be a) because (and here I disagree with Jesse), all that
 exists is an ensemble of isolated observer moments. The future, the past,
 alternative histories, etc.  they all exist in a symmetrical way. It don't
 see how some states can be more ''real'' than other states. Of course, the
 universe we experience seems to be real to us while alternative universes,
 or past or future states of this universe are not being experienced by us.


 So, you must think of yourself at any time as being  randomly sampled from
 the set of all possible observer moments. To get to answer b) you have to
 redefine your identity so that experiencing having done the experiment
 becomes a necessary part of your identity. But this is cheating because
you
 wouldn't say that if ''death'' were replaced by a partial memory erasure
 such that the experience of having done the experiment were wiped out form
 your memory.





 - Original Message - 
 From: Stathis Papaioannou [EMAIL PROTECTED]
 To: [EMAIL PROTECTED]
 Cc: everything-list@eskimo.com
 Sent: Saturday, November 26, 2005 11:51 AM
 Subject: Re: Quantum Immortality and Information Flow


 
  Stathis Papaioannou writes:
  If on the basis of a coin toss the world splits, and in one branch I am
  instantaneously killed while in the other I continue living, there are
  several possible ways this might be interpreted from the 1st person
  viewpoint:
 
  (a) Pr(I live) = Pr(I die) = 0.5
 
  (b) Pr(I live) = 1, Pr(I die) = 0
 
  (c) Pr(I live) = 0, Pr(I die) = 1
 
  Even on this list, there are people who might say (a) above is the case
  rather than (b) or (c).
 
  Bruno Marchal replies:
  Are you sure?
 
  I was thinking of people who accept some ensemble theory such as MWI,
but
  don't believe in QTI. I must admit, I find it difficult to understand
how
  even a dualist might justify (a) as being correct. Would anyone care to
  help?
 
  Stathis
 
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Re: Quantum Immortality and Information Flow

2005-12-02 Thread George Levy




Saibal Mitra wrote:

  Correction, I seem to have misunderstood Statis'  set up. If you really
create a new world and then create and kill the person there then the
probability of survival is 1. This is different from quantum mechanical
branch splitting.

To see this, consider first what would have happened had the person not been
killed. Then his measure would have doubled. But because he is killed in one
of the two copies of Earth, his measure stays the same. In a quantum suicide
experiment his measure would be reduced by a factor two.
  

To say that measure is doubled or halved it is not sufficient to take
the measure at the final point. You really must compare measure at two
points, in effect take a ratio. So depending where the initial point is
you could come to different conclusions. If your initial point is
before the new world is created (and the clone in that world is
killed), then, you are right. There is no change in the measure of the
original person. However, if the initial point is taken after the world
is created but before the clone is killed, then the measure of the clone
goes to zero "in that world." One could always argue
that the world branches and the clone continues living in other worlds.

George




Re: Quantum Immortality and Information Flow

2005-11-30 Thread Stathis Papaioannou


Why does an OM need to contain so much information to link it to other OMs 
making up a person? I certainly don't spend every waking moment reminding 
myself of who I am, let alone going over my entire past history, and I still 
think all my thoughts are my thoughts. I don't think that the fact these 
thoughts are contained in my head makes the difference, because as you 
seemed to agree, continuity of consciousness can in theory extend over 
discontinuities in time and/or space, as in teleportation. On the other 
hand, I could suddenly become psychotic and as a result believe I am a 
completely different person, with a different past; or perhaps my mind could 
be taken over by an alien intelligence with a similar effect. As for one OM 
potentially representing a thought from thousands of different people, that 
is exactly what happens in the multiverse and is one of the key advantages 
of the concept. Suppose you and I happened to have *exactly* the same 
subjective experience at a particular time, say seeing a red shape on a 
white wall at the age of two. This would mean that, for that moment, your 
mind and my mind could have been interchanged, or one of our two minds could 
have been temporarily suspended, without making any subjective difference to 
either of us. An external observer monitoring my body might have noticed a 
momentary blankness if my mental processes were suspended at the moment of 
coincidence, but as far as I was concerned, it would have been exactly the 
same as if I were teleported away to have the red shape experience (which I 
would have had anyway) and teleported back.


Stathis Papaioannou


Stathis Papaioannou wrote:

Brent Meeker writes:

I agree with all you have written below as an explication of what we mean 
by a
person in the multiverse.  But it assumes an objective spacetime in order 
to
define persons by causal continuity.  I thought the point of OMs was to 
provide

a fundamental ontology from which spacetime would be constructed.



While it always seems in real life, as in my example, that there is a 
causal connection between related OMs, this need not necessarily be the 
case. For a2 to think, I stepped into the teleporter a moment ago and to 
consider himself the person a1a2, it is sufficient simply that a2 exist. 
That is, given that a2 exists, it makes no difference whether there is 
information transfer from a1 to a2, whether a1 precedes a2, or whether a1 
exists at all. In general, if the only thing that exists is the set of all 
possible OMs, not ordered in any particular way and each OM completely 
independent and isolated, then the apparent multiverse with its complex 
physical laws results as an emergent phenomenon, or if you prefer, an 
illusion.


That's taking an OM to be like Barbour's time capsule.  They are ordered
according to their contents.  a1a2's OM with the thought that he was in a
teleporter and was a1, connects to a1's OM with the thought that now I am
stepping into a teleporter.  But that brings me back to my objection to 
OMs.

Barbour's time capsules contain whole states of the world.  OMs don't have
enough information to provide the specificity required for connections.  
a1a2's
OM thought could be the thought of thousands of other people.  To be sure, 
if we
take a sequence of a1a2's thoughts and lump them into one OM then that OM 
will
have enough information to place in a unique sequence indentifying a 
person.

But then we've really assumed the thing to be explained.

Brent Meeker



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Re: Quantum Immortality and Information Flow

2005-11-28 Thread Bruno Marchal


Le 27-nov.-05, à 02:18, Kim Jones a écrit :

The search for a consistent meaning to life is then the search for 
certainty about that pattern one recognises as the 1st person 
experience, or the self. I assume that this is not so much for 
confirmation of solipsism but for the knowledge that our pattern 
counts for something amongst all the others. A kind of emotional 
relativity if you will.


And that can be explained in some Darwinian way (once we postulated 
some amount of consistency around us).


OK I should have read the two posts. I think I understand better what 
you are aiming to.


Bruno

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




Re: Quantum Immortality and Information Flow

2005-11-28 Thread Bruno Marchal


Le 27-nov.-05, à 02:25, Saibal Mitra a écrit :

The answer must be a) because (and here I disagree with Jesse), all 
that
exists is an ensemble of isolated observer moments. The future, the 
past,
alternative histories, etc.  they all exist in a symmetrical way. It 
don't

see how some states can be more ''real'' than other states.


But then how could we ever explain why some states seem to be more 
*near*, or more probable than others from our point of view?


Is the choice between Papaioannou's  a, b reflecting(*) the ASSA 
and RSSA difference?


Recall: ASSA = absolute self-sampling assumption. RSSA = relative 
self-sampling assumption.


(*) Stathis Papaioannou writes:

If on the basis of a coin toss the world splits, and in one branch I am
instantaneously killed while in the other I continue living, there are
several possible ways this might be interpreted from the 1st person
viewpoint:

(a) Pr(I live) = Pr(I die) = 0.5

(b) Pr(I live) = 1, Pr(I die) = 0

(c) Pr(I live) = 0, Pr(I die) = 1

Even on this list, there are people who might say (a) above is the case
rather than (b) or (c).



Saibal:

So, you must think of yourself at any time as being  randomly sampled 
from

the set of all possible observer moments.



This could make sense in a pure third person perspective, but then it 
is no more a perspective. And, indeed, to predict the result of 
anything I decide to test, I need to take into account relations 
between observer-moments. Let me throw a dice. Are you saying to us 
that to predict the result I need to take into account all 
observer-moments and sample on them in some uniform way. Why should 
people buy lotto-tickets? They could make the big win by their OM being 
sampled on all OMs.
I'm not saying you are false, but your absolute sample does not 
correspond tour first person experience (including physics) which we 
want to explain. It seems to me.





To get to answer b) you have to
redefine your identity so that experiencing having done the experiment
becomes a necessary part of your identity.


Not some absolute identity, but memories are part of our relative, 
mundane, identity.





But this is cheating because you
wouldn't say that if ''death'' were replaced by a partial memory 
erasure
such that the experience of having done the experiment were wiped out 
form

your memory.


OK, but that is why the experiment is proposed with (absolute) death 
(if that exists) and not with memory erasure. This could change the 
probabilities a lot, and this can admit many different protocol for 
verifying the probability distributions. It is another experiment.

Perhaps I miss your point.

Bruno



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




Re: Quantum Immortality and Information Flow

2005-11-28 Thread Stathis Papaioannou

Saibal Mitra writes:

The answer must be a) because (and here I disagree with Jesse), all that
exists is an ensemble of isolated observer moments. The future, the past,
alternative histories, etc.  they all exist in a symmetrical way. It don't
see how some states can be more ''real'' than other states. Of course, the
universe we experience seems to be real to us while alternative universes,
or past or future states of this universe are not being experienced by us.



 Stathis Papaioannou writes:
 If on the basis of a coin toss the world splits, and in one branch I am
 instantaneously killed while in the other I continue living, there are
 several possible ways this might be interpreted from the 1st person
 viewpoint:

 (a) Pr(I live) = Pr(I die) = 0.5

 (b) Pr(I live) = 1, Pr(I die) = 0

 (c) Pr(I live) = 0, Pr(I die) = 1


Another thought: if I die instantaneously in one of the two branches - that 
is, I don't have time to experience that branch at all - is this not 
functionally equivalent to being copied and instantaneously killed in 
multiple branches? In the next moment, I expect to find myself alive and 
continuing to type this in Melbourne, but dead in Sydney, Paris, Mars etc. - 
dead almost everywhere else in the multiverse, in fact. Given the reasoning 
in support of answer (a), doesn't this mean I should have almost zero 
expectation of finding myself alive in Melbourne in the next moment?


Stathis Papaioannou

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Re: Quantum Immortality and Information Flow

2005-11-27 Thread Stathis Papaioannou

Saibal Mitra writes:


The answer must be a) because (and here I disagree with Jesse), all that
exists is an ensemble of isolated observer moments. The future, the past,
alternative histories, etc.  they all exist in a symmetrical way. It don't
see how some states can be more ''real'' than other states. Of course, the
universe we experience seems to be real to us while alternative universes,
or past or future states of this universe are not being experienced by us.

So, you must think of yourself at any time as being  randomly sampled from
the set of all possible observer moments. To get to answer b) you have to
redefine your identity so that experiencing having done the experiment
becomes a necessary part of your identity. But this is cheating because you
wouldn't say that if ''death'' were replaced by a partial memory erasure
such that the experience of having done the experiment were wiped out form
your memory.



 Stathis Papaioannou writes:
 If on the basis of a coin toss the world splits, and in one branch I am
 instantaneously killed while in the other I continue living, there are
 several possible ways this might be interpreted from the 1st person
 viewpoint:

 (a) Pr(I live) = Pr(I die) = 0.5

 (b) Pr(I live) = 1, Pr(I die) = 0

 (c) Pr(I live) = 0, Pr(I die) = 1

 Even on this list, there are people who might say (a) above is the case
 rather than (b) or (c).

 Bruno Marchal replies:
 Are you sure?

 I was thinking of people who accept some ensemble theory such as MWI, 
but
 don't believe in QTI. I must admit, I find it difficult to understand 
how

 even a dualist might justify (a) as being correct. Would anyone care to
 help?



I agree that all that exists is an ensemble of isolated observer moments 
is a good way to look at it. In fact, that is why I think the best 
objective answer is (c) rather than (b): each OM exists only transiently. 
However, as a human, what I am interested in is the experience (one could 
say, the illusion) of living my life a step at a time which results from the 
existence of certain special OMs in the great and mixed up ensemble of all 
possible OMs. Now, where I disagree with you is in the method and meaning of 
sampling from this ensemble. It is literally true, in a sense, that my next 
experience is more likely to be an OM of relatively high measure: a moment 
from my life in any month other than November 2005; the experiences of a 
Chinese rather than an Australian; death, the content-poor OM of inanimate 
matter. If a third person were randomly pulling OMs from the plenitude and 
setting them down in order, that is indeed what he would get. Amazingly, 
however, when *I* am doing the sampling, my next experience always turns 
out to be... well, something that we all recognise as a next experience. I 
always seem to find that rare OM amongst all the other other ones where I 
turn into a turnip, or I'm suddenly 95 years old, or all the other countless 
possibilities. I don't even have to go looking for it: if it's out there at 
all, I'll find it. If there are several candidate next moments, including 
ones where I have suffered partial memory loss, which one I (that is, one 
version of me) experience will seem to be determined probabilistically. And 
if there are no candidate next moments at all, then I die.


I have used I rather loosely and without defining it because there is no 
objective truth of the matter when considering personal identity. I may be 
physically completely different (i.e. comprised of different matter) today 
than I was a year ago, and my mental state and memories may only be 
approximately similar to what they were then, but I am sure I am still the 
same person, and that is what counts. If I had undergone a head injury or a 
dementing illness in the past year, I would be even less similar now than I 
was then, but I would probably still think I was the same person unless I 
was really far gone, in which case it probably would be the same as if I had 
died. These are matters millions of people deal with every day: you don't 
have to bring up multiple copies in other worlds.



Stathis Papaioannou

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RE: Quantum Immortality and Information Flow

2005-11-27 Thread Stathis Papaioannou

Jonathan Colvin writes:


Saibal wrote:
 The answer must be a) because (and here I disagree with
 Jesse), all that exists is an ensemble of isolated observer
 moments. The future, the past, alternative histories, etc.
 they all exist in a symmetrical way. It don't see how some
 states can be more ''real'' than other states. Of course, the
 universe we experience seems to be real to us while
 alternative universes, or past or future states of this
 universe are not being experienced by us.


 So, you must think of yourself at any time as being  randomly
 sampled from the set of all possible observer moments.

delurk

I'm not sure how this works. Suppose I consider my state now at time N as
a random sample of all observer moments. Now, after having typed this
sentence, I consider my state at time N + 4 seconds. Is this also a 
random
sample on all observer moments?  I can do the same at now N+10, and 
so-on.

It seems very unlikely that 3 random samples would coincide so closely. So
in what sense are these states randomly sampled?


They would be randomly sampled if, godlike, some third person pulled them 
out of the ensemble of all possible observer moments - and in that case, it 
certainly would be surprising if these three turned up one after the other. 
However, from the first person perspective, they don't need to be sampled 
at all. It suffices that these three OMs simply exist somewhere in the 
plenitude, and - by definition - there will also exist an observer who 
experiences (at least) these three states.


The situation is slightly different if there is more than one OM that would 
fit a particular state. For example, if there are two distinct OMs that 
would fit into the sequence as N + 4, then at that point the number of 
observers doubles. For the single observer just before the duplication, this 
would be seen as a 1/2 probability of experiencing one or the other state.


Stathis Papaioannou

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Re: Quantum Immortality and Information Flow

2005-11-27 Thread Saibal Mitra

- Original Message - 
From: Jonathan Colvin [EMAIL PROTECTED]
To: everything-list@eskimo.com
Sent: Sunday, November 27, 2005 05:49 AM
Subject: RE: Quantum Immortality and Information Flow


 Saibal wrote:
  The answer must be a) because (and here I disagree with
  Jesse), all that exists is an ensemble of isolated observer
  moments. The future, the past, alternative histories, etc.
  they all exist in a symmetrical way. It don't see how some
  states can be more ''real'' than other states. Of course, the
  universe we experience seems to be real to us while
  alternative universes, or past or future states of this
  universe are not being experienced by us.
 
 
  So, you must think of yourself at any time as being  randomly
  sampled from the set of all possible observer moments.

 delurk

 I'm not sure how this works. Suppose I consider my state now at time N
as
 a random sample of all observer moments. Now, after having typed this
 sentence, I consider my state at time N + 4 seconds. Is this also a
random
 sample on all observer moments?  I can do the same at now N+10, and
so-on.
 It seems very unlikely that 3 random samples would coincide so closely. So
 in what sense are these states randomly sampled?

It's a bit like symmetry breaking. You have an ensemble of all possible
observer moment, but each observer moment can only experience its own state.
So, the OM samples itself.

There exists an observer moment representing you at N seconds, at N + 4
seconds and at all possible other states. They all ''just exist'' in the
plenitude, as Stathis wrote. The OM  representing you at N + 4 has the
memory of being the OM at N. Subjectively the OMs experience time evolution,
even though the plenitude itself doesn't have a time evolution at the
fundamental level.


Although it is a bit strange to think about time evolution in this way, it
is necessary to resolve paradoxes you get when contemplating doubling and
suicide experiments. It is precisely in these cases that our naive notion of
time evolution breaks down.


Saibal



Re: Quantum Immortality and Information Flow

2005-11-27 Thread Brent Meeker

Saibal Mitra wrote:
- Original Message - 
From: Jonathan Colvin [EMAIL PROTECTED]

To: everything-list@eskimo.com
Sent: Sunday, November 27, 2005 05:49 AM
Subject: RE: Quantum Immortality and Information Flow




Saibal wrote:


The answer must be a) because (and here I disagree with
Jesse), all that exists is an ensemble of isolated observer
moments. The future, the past, alternative histories, etc.
they all exist in a symmetrical way. It don't see how some
states can be more ''real'' than other states. Of course, the
universe we experience seems to be real to us while
alternative universes, or past or future states of this
universe are not being experienced by us.


So, you must think of yourself at any time as being  randomly
sampled from the set of all possible observer moments.


delurk

I'm not sure how this works. Suppose I consider my state now at time N


as


a random sample of all observer moments. Now, after having typed this
sentence, I consider my state at time N + 4 seconds. Is this also a


random


sample on all observer moments?  I can do the same at now N+10, and


so-on.


It seems very unlikely that 3 random samples would coincide so closely. So
in what sense are these states randomly sampled?



It's a bit like symmetry breaking. You have an ensemble of all possible
observer moment, but each observer moment can only experience its own state.
So, the OM samples itself.

There exists an observer moment representing you at N seconds, at N + 4
seconds and at all possible other states. They all ''just exist'' in the
plenitude, as Stathis wrote. The OM  representing you at N + 4 has the
memory of being the OM at N. 


This I find confusing.  How is there memory associated with an obserever moment? 
 Is it equivocation on memory?  As an experience, remembering something takes 
much longer than what I would call a moment.  It may involve a sequence 
images, words, and emotions.  Of course in a materialist model of the world the 
memories are coded in the physical configuration of your brain, even when not 
being experienced; but an analysis that takes OM's as fundamental can't refer to 
that kind of memories.


Brent Meeker



RE: Quantum Immortality and Information Flow

2005-11-27 Thread Jonathan Colvin
 
Saibal wrote:
   The answer must be a) because (and here I disagree with
   Jesse), all that exists is an ensemble of isolated observer
   moments. The future, the past, alternative histories, etc.
   they all exist in a symmetrical way. It don't see how some
   states can be more ''real'' than other states. Of course, the
   universe we experience seems to be real to us while
   alternative universes, or past or future states of this
   universe are not being experienced by us.
  
  
   So, you must think of yourself at any time as being  randomly
   sampled from the set of all possible observer moments.
 
  delurk
 
  I'm not sure how this works. Suppose I consider my state 
 now at time N
 as
  a random sample of all observer moments. Now, after having 
 typed this
  sentence, I consider my state at time N + 4 seconds. Is 
 this also a
 random
  sample on all observer moments?  I can do the same at now 
 N+10, and
 so-on.
  It seems very unlikely that 3 random samples would coincide 
 so closely. So
  in what sense are these states randomly sampled?
 
 It's a bit like symmetry breaking. You have an ensemble of 
 all possible
 observer moment, but each observer moment can only experience 
 its own state.
 So, the OM samples itself.
 
 There exists an observer moment representing you at N 
 seconds, at N + 4
 seconds and at all possible other states. They all ''just 
 exist'' in the
 plenitude, as Stathis wrote. The OM  representing you at N + 4 has the
 memory of being the OM at N. Subjectively the OMs experience 
 time evolution,
 even though the plenitude itself doesn't have a time evolution at the
 fundamental level.

I understand all that, but I still don't see in what sense these OM's are
randomly sampled.

Here's a related question. The DDA insists that we must all consider
ourselves random observers on our reference class, whatever it is (class of
all observers is standard). Now, if I am a random observer, and you (Saibal)
are a random observer, what are the odds that two observers selected
randomly from the class of all observers would be discoursing on the same
mailing list? We can only conclude that one of us can not be random, but
must have been selected by the other. But did I select you, or did you
select me? If we select each other, the randomness issue is not resolved.

Another possibility is, I suppose, to simply *define* randomness as observer
self-selection. Perhaps observer self-selection is the only truly random
phenomenon in the universe (everything else appearing random is merely
unpredictable). But it is then a purely a first-person phenomenon, and I can
not consider anything else in the universe (including *your* observer
moments) as random. 

Jonathan Colvin



Re: Quantum Immortality and Information Flow

2005-11-27 Thread Stathis Papaioannou

I agree with everything Jesse says here.

Stathis Papaioannou


Stathis Papaioannou wrote:

I was thinking of people who accept some ensemble theory such as MWI, but 
don't believe in QTI. I must admit, I find it difficult to understand how 
even a dualist might justify (a) as being correct. Would anyone care to 
help?


What do you think of my argument here?

http://www.mail-archive.com/everything-list@eskimo.com/msg04692.html


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Re: Quantum Immortality and Information Flow

2005-11-27 Thread Stathis Papaioannou

Brent Meeker writes:

[quoting Saibal Mitra]

There exists an observer moment representing you at N seconds, at N + 4
seconds and at all possible other states. They all ''just exist'' in the
plenitude, as Stathis wrote. The OM  representing you at N + 4 has the
memory of being the OM at N.


This I find confusing.  How is there memory associated with an obserever 
moment?  Is it equivocation on memory?  As an experience, remembering 
something takes much longer than what I would call a moment.  It may 
involve a sequence images, words, and emotions.  Of course in a materialist 
model of the world the memories are coded in the physical configuration of 
your brain, even when not being experienced; but an analysis that takes 
OM's as fundamental can't refer to that kind of memories.


It is true that human cognition, memories etc. are not instantaneous. There 
are two ways to keep the OM concept useful despite this. One is to extend 
each moment so that it encompasses, for example, the minimum period of 
awareness (probably a substantial fraction of a second), or any interval of 
arbitrary length, such as the waking hours of a day. This still allows one 
to think about questions involving continuity of personal identity where 
multiple copies or near-copies of a given mind are running simultaneously, 
the interval of the OMs under consideration being tailored to the particular 
situation. The other way is to bite the bullet and allow instantaneous 
part-cognitions. A memory is then only associated with an OM during the act 
of remembering, and each instantaneous OM covers only an instant of that 
act, in the same way a frame in a film covers only an instant of the action 
depicted by the series of frames.


Stathis Papaioannou

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Re: Quantum Immortality and Information Flow

2005-11-27 Thread Brent Meeker

Stathis Papaioannou wrote:

Brent Meeker writes:

[quoting Saibal Mitra]


There exists an observer moment representing you at N seconds, at N + 4
seconds and at all possible other states. They all ''just exist'' in the
plenitude, as Stathis wrote. The OM  representing you at N + 4 has the
memory of being the OM at N.



This I find confusing.  How is there memory associated with an 
obserever moment?  Is it equivocation on memory?  As an experience, 
remembering something takes much longer than what I would call a 
moment.  It may involve a sequence images, words, and emotions.  Of 
course in a materialist model of the world the memories are coded in 
the physical configuration of your brain, even when not being 
experienced; but an analysis that takes OM's as fundamental can't 
refer to that kind of memories.



It is true that human cognition, memories etc. are not instantaneous. 
There are two ways to keep the OM concept useful despite this. One is to 
extend each moment so that it encompasses, for example, the minimum 
period of awareness (probably a substantial fraction of a second), or 
any interval of arbitrary length, such as the waking hours of a day. 
This still allows one to think about questions involving continuity of 
personal identity where multiple copies or near-copies of a given mind 
are running simultaneously, the interval of the OMs under consideration 
being tailored to the particular situation. 


But giving OMs duration seems to invite other incoherence.  It means that time 
cannot be understood as a sequence of timeless OMs.  On the other hand it solves 
more than just the memory problem; if OMs have duration, then the durations 
could overlap and thus define worlds and personal identity - i.e. provide 
the accessiblity relation.


The other way is to bite the 
bullet and allow instantaneous part-cognitions. A memory is then only 
associated with an OM during the act of remembering, and each 
instantaneous OM covers only an instant of that act, in the same way a 
frame in a film covers only an instant of the action depicted by the 
series of frames.


I have difficultly with an instant of cognition.  A film records an instant of 
spatial relations, but how is one to understand a non-extensive, instant of 
cognition  - certainly not by simple introspection.  But it seems that getting 
an explanation of the world via introspection is why OMs were appealing in the 
first place.


Brent Meeker



Re: Quantum Immortality and Information Flow

2005-11-26 Thread Jesse Mazer


Stathis Papaioannou wrote:

I was thinking of people who accept some ensemble theory such as MWI, but 
don't believe in QTI. I must admit, I find it difficult to understand how 
even a dualist might justify (a) as being correct. Would anyone care to 
help?


What do you think of my argument here?

http://www.mail-archive.com/everything-list@eskimo.com/msg04692.html




Re: Quantum Immortality and Information Flow

2005-11-26 Thread Quentin Anciaux
Le Samedi 26 Novembre 2005 18:47, Jesse Mazer a écrit :
Stathis Papaioannou wrote:
 I was thinking of people who accept some ensemble theory such as MWI, but
 don't believe in QTI. I must admit, I find it difficult to understand how
 even a dualist might justify (a) as being correct. Would anyone care to
 help?

What would be the meaning to accept solution a ?

Are we only sentient entities for a small(art) moment ?

It sounds stupid to only be sentient for a moment... just because a moment has 
no meaning for entities like us. Like I like to repeat, what could it means 
to not be self aware... ? Could we as first person perspective be aware of 
not being aware ? It sounds non sense.

While I agree it is quite of topic.. this is something that I got lot of 
interest into. Why are we looking for a consistent meaning of our own life ?

Quentin



Re: Quantum Immortality and Information Flow

2005-11-26 Thread Kim Jones


On 27/11/2005, at 10:07 AM, Quentin Anciaux wrote:




While I agree it is quite of topic.. this is something that I got  
lot of
interest into. Why are we looking for a consistent meaning of our  
own life ?


Quentin


How can anything be off-topic on a list calling itself  
Everything? ;


Because that's what the human brain does. The nature of the system  
called human brain involves use of a software (our Greek Gang of  
Three judgment-based thinking system) that proceeds on pattern- 
recognition for shaping all data. The brain in turn can also supply  
patterns of its own. A pattern can be many things of course, but it  
in order for our brain to deal with it at all, it has to exhibit some  
degree of consistency or regularity, however crazy this may turn out  
to be. If you can see meaning in a piece of music then you know what  
I mean instantly. If the consistency or regularity don't occur in the  
data (or we simply don't percieve it for whatever reason) then our  
brains impose a pattern on the data so we can sift it (en faire le  
triage).


I always like to say that the absence of real knowledge of something  
has never been much of an obstacle to humans tricking up  
explanations of one kind or another. Without its patterns of  
recognition, the brain is a very halting machine.


Also, if we don't actually know something then we can always believe  
something, which, it turns out, is almost as good (but not quite as  
good).


The search for a consistent meaning to life is then the search for  
certainty about that pattern one recognises as the 1st person  
experience, or the self. I assume that this is not so much for  
confirmation of solipsism but for the knowledge that our pattern  
counts for something amongst all the others. A kind of emotional  
relativity if you will.


The patterns of recognition help us to survive but for what do we  
survive? If the white rabbit DOES fly in through the window, then  
you've got a problem with the consistency of that meaning. Given half  
an hour and a bit of reflection though, you would probably convince  
yourself of some explanation. Which is to say you would at least  
supply and append (from your own brain) the minimal pattern of  
recognition Gee, if it happened once it could happen again, so I  
will suspend my judgment). Having seen once in my life what I later  
came to believe was a UFO, I realise now that  for many years I  
unconsciously believed some minimal explanation of what I saw  
unquestioningly until I really, rationally examined in detail this  
belief. So, whatever we need in the way of consistency of meaning,  
we can never be certain we aren't just making it all up as we go  
along. I think this brings us back to Bruno and Goedel?


Kim Jones



RE: Quantum Immortality and Information Flow

2005-11-26 Thread Jonathan Colvin
Saibal wrote:  
 The answer must be a) because (and here I disagree with 
 Jesse), all that exists is an ensemble of isolated observer 
 moments. The future, the past, alternative histories, etc.  
 they all exist in a symmetrical way. It don't see how some 
 states can be more ''real'' than other states. Of course, the 
 universe we experience seems to be real to us while 
 alternative universes, or past or future states of this 
 universe are not being experienced by us.
 
 
 So, you must think of yourself at any time as being  randomly 
 sampled from the set of all possible observer moments. 

delurk

I'm not sure how this works. Suppose I consider my state now at time N as
a random sample of all observer moments. Now, after having typed this
sentence, I consider my state at time N + 4 seconds. Is this also a random
sample on all observer moments?  I can do the same at now N+10, and so-on.
It seems very unlikely that 3 random samples would coincide so closely. So
in what sense are these states randomly sampled?

Jonathan Colvin



Re: Quantum Immortality and Information Flow

2005-11-26 Thread George Levy

Stathis Papaioannou wrote:



Stathis Papaioannou writes:
If on the basis of a coin toss the world splits, and in one branch I 
am instantaneously killed while in the other I continue living, there 
are several possible ways this might be interpreted from the 1st 
person viewpoint:


(a) Pr(I live) = Pr(I die) = 0.5

(b) Pr(I live) = 1, Pr(I die) = 0

(c) Pr(I live) = 0, Pr(I die) = 1 



Your example underscores the need for interpreting Pr as a relative 
concept ( this is my favorite point of view):
c) is A observing A. It is seen through the first person A who is killed 
in one branch and live in another branch. This is called the first 
person on this list.
a) is B observing A: It is seen through a first person B who witnesses 
the event hapenning to A but lives in both branches. His point of view 
is called the third person on this list:
b) is C observing A. It is seen through a first person C who experiences 
the complement events of A. He lives when A dies and vice versa. The 
probability that he will see A live is 0. We do not have a name for this 
point of view on this list but I could suggest the complement first 
person.


Thus all answers are correct depending on your relative point of view.

George



Re: Quantum Immortality and Information Flow

2005-11-26 Thread George Levy

Please disregard previous post. The b and c cases were inverted.


Stathis Papaioannou wrote:



Stathis Papaioannou writes:
If on the basis of a coin toss the world splits, and in one branch I 
am instantaneously killed while in the other I continue living, there 
are several possible ways this might be interpreted from the 1st 
person viewpoint:


(a) Pr(I live) = Pr(I die) = 0.5

(b) Pr(I live) = 1, Pr(I die) = 0

(c) Pr(I live) = 0, Pr(I die) = 1 




Your example underscores the need for interpreting Pr as a relative 
concept ( this is my favorite point of view):
b) is A observing A. It is seen through the first person A who is 
killed in one branch and live in another branch. This is called the 
first person on this list.
a) is B observing A: It is seen through a first person B who witnesses 
the event hapenning to A but lives in both branches. His point of view 
is called the third person on this list:
c) is C observing A. It is seen through a first person C who 
experiences the complement events of A. He lives when A dies and vice 
versa. The probability that he will see A live is 0. We do not have a 
name for this point of view on this list but I could suggest the 
complement first person.


Thus all answers are correct depending on your relative point of view.

George








Re: Quantum Immortality and Information Flow

2005-11-24 Thread Bruno Marchal


Le 24-nov.-05, à 08:52, Stathis Papaioannou a écrit :


Bruno Marchal writes:

The main idea of Kripke has consisted in saying that the modal 
formula Bp (also written []p) is true at world a, if p is true in all 
the worlds you can access from a. p is relatively necessary at a.
For example, if the world are countries and if you have to pay taxes 
in all countries that you can access from where you are, then taxes 
are necessary (relatively to a).


That is, p is necessary at world a if p is true for all worlds b 
such that aRb. It is intuitively normal: a proposition is necessary 
for you if it is true in all world you can access.


[I have cut this short - Bruno continues at some length from this 
beginning]


What counts as an accessible world? It seems that in answering this 
you have to propose or imply a theory of personal identity.




Actually I would say it is the other way round. Kripke introduces its 
abstract multiverses in order to be able to make simple the reasoning 
for large class of modal logics, which are somehow traditional tools 
for handling complex philosophical notions, including notions of 
personal identity. That is the way I proceed to. By comp I inherit of 
the modal logic G and G* from the most standard theory of 
self-reference (the Godel one) and I use them to analyse two (at least) 
notions of personal identity (the third person one and the first person 
one).







If on the basis of a coin toss the world splits, and in one branch I 
am instantaneously killed while in the other I continue living, there 
are several possible ways this might be interpreted from the 1st 
person viewpoint:


(a) Pr(I live) = Pr(I die) = 0.5



I hope everyone sees that this (a) is not defensible once we *assume* 
comp.








(b) Pr(I live) = 1, Pr(I die) = 0



And this one (b) is a consequence of comp.








(c) Pr(I live) = 0, Pr(I die) = 1

Option (c) may look a bit strange but is the one that I favour: all 
first person experiences are transient, all branches are dead ends, no 
world is accessible from any other world.



I think I figure out why you say that and why you take it probably as a 
consequence of comp.

Let us see.





However, the various independent, transient observer moments are 
ordered in such a way in what we experience as ordinary life that the 
illusion of (b) occurs.


Yes right. But that illusion is all what the first person notion is 
all about. Your c is too strong. What would you say if your comp 
doctor proposes you an artificial brain and adds that the Pr(I die), 
for you, is 1. I think you would say no doctor. Then the doctor (not 
you!, I know you are doctor!) adds that in all case Pr(I die) = 1. Then 
you will tell him that he has not given any clue about the probability 
your first person illusion (I hate this word) lasts. The real 
question we ask to the doctor is what is the probability my illusion 
will lasts *as* it lasts for any other medical operation when it is 
said the operation has been successful.
What I have called Papaioannou's multiverse are just your transient 
observer moments *together* with the order you are indeed adding on 
them for giving sense to ordinary experience. That order *is* an 
accessibility relation.






This covers such (theoretical, at present) cases as the apparent 
continuity of identity between two observer moments that just happen 
to seem to be consecutive frames in a person's life even though 
there is no physical or informational connection between them.


But you cannot deny that with comp, there *is* some informational 
connection between them. The connection will appear to be exclusively 
mathematical and immaterial.  And will appear to be the logical root of 
another illusion: a physical world. We know this by UDA (the 
Universal Dovetailer Argument), but we need to isolate completely the 
structure of the multiverse extractible from comp if we want to derive 
the precise physics from comp (and then to compare with the empirical 
physics to evaluate empirically the plausibility of comp (or of its 
many variants).


Bruno

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




Re: Quantum Immortality and Information Flow

2005-11-24 Thread Stathis Papaioannou

Bruno Marchal writes:

If on the basis of a coin toss the world splits, and in one branch I am 
instantaneously killed while in the other I continue living, there are 
several possible ways this might be interpreted from the 1st person 
viewpoint:


(a) Pr(I live) = Pr(I die) = 0.5



I hope everyone sees that this (a) is not defensible once we *assume* comp.


Good, we agree here. I don't think everyone on this list would agree.


(b) Pr(I live) = 1, Pr(I die) = 0



And this one (b) is a consequence of comp.




(c) Pr(I live) = 0, Pr(I die) = 1

Option (c) may look a bit strange but is the one that I favour: all first 
person experiences are transient, all branches are dead ends, no world is 
accessible from any other world.



I think I figure out why you say that and why you take it probably as a 
consequence of comp.

Let us see.





However, the various independent, transient observer moments are ordered 
in such a way in what we experience as ordinary life that the illusion of 
(b) occurs.


Yes right. But that illusion is all what the first person notion is all 
about. Your c is too strong. What would you say if your comp doctor 
proposes you an artificial brain and adds that the Pr(I die), for you, is 
1. I think you would say no doctor. Then the doctor (not you!, I know you 
are doctor!) adds that in all case Pr(I die) = 1. Then you will tell him 
that he has not given any clue about the probability your first person 
illusion (I hate this word) lasts. The real question we ask to the doctor 
is what is the probability my illusion will lasts *as* it lasts for any 
other medical operation when it is said the operation has been successful.
What I have called Papaioannou's multiverse are just your transient 
observer moments *together* with the order you are indeed adding on them 
for giving sense to ordinary experience. That order *is* an accessibility 
relation.


OK, you've put that quite well. Even if continuity of identity is an 
illusion, it is an important illusion. An analogy would be going to the 
cinema to see a movie: the reality might be that we are watching a series 
of still images, but the important thing for the audience is that the 
illusion of motion is maintained by having a certain minimum frame rate. So 
yes, this does give rise to an accessibility relationship, but it 
presupposes a theory of personal identity. Even on this list, there are 
people who might say (a) above is the case rather than (b) or (c).


This covers such (theoretical, at present) cases as the apparent 
continuity of identity between two observer moments that just happen to 
seem to be consecutive frames in a person's life even though there is no 
physical or informational connection between them.


But you cannot deny that with comp, there *is* some informational 
connection between them. The connection will appear to be exclusively 
mathematical and immaterial.  And will appear to be the logical root of 
another illusion: a physical world. We know this by UDA (the Universal 
Dovetailer Argument), but we need to isolate completely the structure of 
the multiverse extractible from comp if we want to derive the precise 
physics from comp (and then to compare with the empirical physics to 
evaluate empirically the plausibility of comp (or of its many variants).


What I meant by informational connection was actual information transfer 
from one frame to the next, by some physical process. This is what happens 
normally by virtue of the fact that consecutive frames are implemented by 
the same physical brain. It is also what would happen, in a different way, 
with teleportation.  This is sufficient for the experience of continuity of 
consciousness, but it is not necessary: the appropriate frames or observer 
moments might occur completely randomly in different parts of the 
multiverse, and the first person experience would be the same. (Such is not 
the case for observation of third persons: the frames or observer moments 
must be explicitly ordered, or they will be lost in the noise). Is this what 
you mean by the connection will appear to be exclusively mathematical and 
immaterial?


Stathis Papaioannou

_
Start something musical - 15 free ninemsn Music downloads! 
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Re: Quantum Immortality and Information Flow

2005-11-21 Thread Bruno Marchal


Le 19-nov.-05, à 22:56, Russell Standish a écrit :



On Sat, Nov 19, 2005 at 04:22:58PM +0100, Bruno Marchal wrote:

Now observation and knowledge are defined in the logics of
self-reference, i.e. by transformation of G and G*, and so are each
multiplied by two. Actually and amazingly for the knower (the first
person) G and G* give the same logic, like if the first person
conflates truth and provability. But for the notion of observation, G
and G* give again different logics, so that the observer can
distinguish communicable observations (physical facts) and non
communicable observations (sensations, I would argue).


Are you now saying that your operators

   Pp = Bp  -B-p

and

   Op = Bp  p  -B-p

correspond to to observe (Op being to validly observe I
suppose)?. Previously, you would say that Pp is to bet on p, and Op
to correctly bet on p, which never really made sense to me. What's
the French word you would use for this - I may know it, or perhaps I
can figure the relevant English term from a dictionary.




Let me first explain in few words a plausible logician conception of a 
multiverse. I borrow the term multiverse from FOR, but I think we 
should be neutral about what is really a universe, or a world, or a 
state, or an observer-moment: the only thing which matter is that we 
have many of them, and that they are related by a relation of 
accessibility. So a multiverse is just a set W (of elements called 
worlds) and a binary relation R defined on it.  Let us use the letter 
a, b, c, d, ... for the worlds. So aRb just means that the world b is 
accessible from the world a. You can travel from a to b.
Note that I am not pretending that the real multiverse (perhaps the 
quantum one) is of that type, but it is good to begin with that 
familiar sort of Kripke multiverse, and then to correct it.


Now we assume that all the worlds obey classical logic:  if p is true 
in world a, and if q is true in world a, then propositional formula 
like (p  q), (p - q) etc. are true at a, and ~p is false at a, etc. 
In particular, all classical tautologies are true in all worlds of all 
multiverse independently of the assignment of truth value to the 
sentence letter p, q, r, etc.


The main idea of Kripke has consisted in saying that the modal formula 
Bp (also written []p) is true at world a, if p is true in all the 
worlds you can access from a. p is relatively necessary at a.
For example, if the world are countries and if you have to pay taxes in 
all countries that you can access from where you are, then taxes are 
necessary (relatively to a).


That is, p is necessary at world a if p is true for all worlds b such 
that aRb. It is intuitively normal: a proposition is necessary for you 
if it is true in all world you can access.


Then a proposition is possible at world a if it is not necessary that 
~a. So possible p, written Dp, or p, can be seen as an abbreviation 
of ~B~p. Note that if Dp is true at a, it means there is an accessible 
world (where p is true) from a. In particular, given that the constant 
true t is true in all worlds, Dt really means I can access to some 
world (I am alive, if you want).


Now, there are relation between the structure of the multiverse, i.e. 
the nature of its accessibility relation, and the formula which are 
true in each world. It should be easy to guess that if the multiverse 
is reflexive (i.e. all worlds are accessible from themselves) then the 
formula Bp - p is true in all the worlds, independently of the truth 
value of the sentence letters. Slightly less easy: the reverse is true: 
if Bp - p is true in all worlds, independently of the assignment of 
true/false to the sentence letters, then the multiverse is reflexive. 
We say that the reflexive multiverse characterizes the formula Bp - p. 
It means the formula remains invariant when we travel in that 
multiverse.
It can be shown that the symmetrical multiverse, that is those where 
the accessibility relation is symmetric, characterizes the formula p - 
BDp. The transitive multiverse characterizes Bp - BBp. etc.


Of special interest in this thread are the dead-end world, or 
cul-de-sac observer-moment (we have use many name for them). A world a, 
in a multiverse W, is said to be a dead end or a cul-de-sac world if, 
when you are in a, there is no more world in which you can acceded. So, 
in such world no proposition are possible, so whatever proposition p 
is, ~Dp is always false. By classical logic B~p is always true. This is 
true whatever p is, in particular this is true for its negation ~p. So 
in a dead end world, all proposition are necessary and none is 
possible. Not a funny place!


Now, when B represents the Godel-Lob provability predicate, i.e. when B 
represents provability in or by a sufficiently rich formal 
system/machine, it can be shown that the humble multiverse, that is 
those where all worlds have access to a dead end world, characterizes 
B. In that case Dp = ~B~p = ~p is not provable = p 

Re: Quantum Immortality and Information Flow

2005-11-19 Thread Russell Standish
On Sat, Nov 19, 2005 at 04:22:58PM +0100, Bruno Marchal wrote:
 Now observation and knowledge are defined in the logics of 
 self-reference, i.e. by transformation of G and G*, and so are each 
 multiplied by two. Actually and amazingly for the knower (the first 
 person) G and G* give the same logic, like if the first person 
 conflates truth and provability. But for the notion of observation, G 
 and G* give again different logics, so that the observer can 
 distinguish communicable observations (physical facts) and non 
 communicable observations (sensations, I would argue). 

Are you now saying that your operators 

   Pp = Bp  -B-p

and

   Op = Bp  p  -B-p

correspond to to observe (Op being to validly observe I
suppose)?. Previously, you would say that Pp is to bet on p, and Op
to correctly bet on p, which never really made sense to me. What's
the French word you would use for this - I may know it, or perhaps I
can figure the relevant English term from a dictionary.

Cheers


-- 
*PS: A number of people ask me about the attachment to my email, which
is of type application/pgp-signature. Don't worry, it is not a
virus. It is an electronic signature, that may be used to verify this
email came from me if you have PGP or GPG installed. Otherwise, you
may safely ignore this attachment.


A/Prof Russell Standish  Phone 8308 3119 (mobile)
Mathematics0425 253119 ()
UNSW SYDNEY 2052 [EMAIL PROTECTED] 
Australiahttp://parallel.hpc.unsw.edu.au/rks
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Re: Quantum Immortality and Information Flow

2005-11-18 Thread Stephen Paul King

Dear Bruno,

   Are you claiming that the communicable part is to the non-communicable 
part as the classical is to the quantum? The Non-cloning aspect of QM and 
the copyability of the classical seems to be implied. Is this intentional?


Onward!

Stephen

- Original Message - 
From: Bruno Marchal [EMAIL PROTECTED]

To: [EMAIL PROTECTED]
Cc: Everything-List List everything-list@eskimo.com
Sent: Friday, November 18, 2005 10:03 AM
Subject: Re: Quantum Immortality and Information Flow


snip

Well, actually I hope it will gives the qubits.
I am not contesting the Everett-Hartle-... Deutsch-Zurek explanation of 
how bits come from qubits. Just saying comp gives a  path from bits to 
qubits too.  A double path.
It is the incompleteness phenomenon(*)  which makes that path double, i.e. 
separated into a communicable part and a non communicable part explaining 
simultaneously quanta and qualia (I would argue).




Re: Quantum Immortality and Information Flow

2005-11-16 Thread Bruno Marchal

Le 15-nov.-05, à 10:56, Brian Scurfield a écrit :




--- In [EMAIL PROTECTED], Bruno Marchal [EMAIL PROTECTED]
wrote:


It has often been pointed out on this list that universes are those
parts of the multiverse down which information flows. So Harry
Potter universes are not in fact universes.


What do you mean by parts of the multiverse down which information
flows?


OK, let's start with information. I have in mind David's qualitative
definition here:

http://xxx.lanl.gov/abs/quant-ph/0104033

To quote:

1. A physical system S *contains information* about a parameter b if …
the probability of some outcome of some measurement on S depends on b.

2. A physical system S *contains no information* about b if … there
exists a complete description of S that is independent on b.

What is meant by information flow is explained here:

http://groups.yahoo.com/group/Fabric-of-Reality/message/9247

Basically, information flows when the output depends in some way on
the input.

As David has shown, the structure of the multiverse is determined by
information flow. A universe is a part of the multiverse where
information flows freely.






OK. I guess you know that this is not a standard use of the term 
information, like the one of Shannon, where the bits measure some 
degree of surprise and unpredictibility (and this can been make precise 
with notion of Kolmogorov/Chaitin/Solovay notion of information).
David Deutsch's notion of information can be related to some logician's 
attempt to define a sort of qualitative information, and as such it is 
quite interesting, but also natural, to find it in an attempt to 
retrieve classical computational histories from the quantum theory.
Now you should keep in mind that David does postulate the existence of 
some continuum causal structure, and, as you know, I am doubtful this 
can make sense once we accept the computationalist hypothesis (cf 
Maudlin's Olympia, my work, etc.). Actually I think David Hume makes 
already important steps in that direction.
Just to illustrate: imagine the case of iterated self-duplication with 
reconstitutions in Sidney and Beijing: S and B. From the point of view 
of the average candidate normal histories, in the form of sequences 
of P and S,  will be highly unpredictable, but in all case there will 
be no causal relations between the events I feel myself to be in S or 
I feel myself to be in P.
Exceptional histories, like the one in which the sequence gives the 
binary digits of the number PI, play the role, curiously enough, of the 
Harry Potter histories, in that case.
So the two notion of information are quite complementary. It is almost 
like one grows up when the other diminishes.








Harry Potter universes are just improbable, and information grows to
much there.


Things spontaneously organise themselves in an HPU, but the output
does not depend on the input; there is no information flow in the
sense described above.




So I agree. And of course I was considering a Shannon form of 
information.







When Harry Potter does a trick, in almost all
universes the trick does not work. But one cannot say the trick
succeeded in those universes that do become HPU's because one can't
single out beforehand those exceptionally rare universes that will
become HPU's.




I agree.








It is almost like they got singularities in the amount of
information. But death, well, really it is an open problem, because
you must take into account the normal (statistical, based on the
measure on the observer/moment/states/worlds...) possible
histories just going locally through exceptional states,


Meaningful histories must have a flow of information right?




I don't think so. I would say that meaningful histories are the 
relatively consistent (non contradictory) one---which will get some 
right measure assuming comp, and the correctness of my derivation, to 
be sure. Those meaningful histories will appear, from the observer 
first person point of view be related to some local flux of information 
in David's sense. But I don't know how to take for granted those 
meaningful histories at the start (unless, like David, you already 
postulate some prior programs as an explanation of the appearance of 
the universe. But then again you will be confronted with the comp 
version of the Mind/Body, or 1-person/3-person relations again.









 In some
histories, the Universal Dovetailer has outputted a series of random
numbers that just happen to be indistinguishable from your life
history up to today. In these histories, your past state does not
determine your present state (although they are in every way
indistinguishable from histories where your past state really does
determine your present state).




I would say you belong to all histories. But with comp you are so 
constituted that only the consistent one will make sense and will be 
stable enough.







 Almost all of these histories will turn
to junk at the very next moment.