On 17 Apr 2012, at 11:23, Robin Faichney wrote:
Hi Bruno,
This is very interesting for me, my approach to information is via the
mind-body and "hard" problems, and I'm sympathetic to
computationalism. On the other hand, I have difficulties understanding
much of what you say here. Let me focus on one point for now though.
Tuesday, April 17, 2012, 8:48:48 AM, Bruno wrote:
Let me sketch the reasoning shortly. If I can survive with a
digitalizable brain, then I am duplicable. For example I could, in
principle, be "read and cut" in Helsinki (say) and pasted in two
different places, like Moscow and Washington (to fix the thing).
The subject to such a duplication experiment, knowing the protocol
in advance, is unable to predict in advance where he will *feel to
be* after the duplication. We can iterate such process and prove
that at such iteration the candidate, seeing if he feels to be in W
or in M, receive a bit of information, and that his best way to
predict his experience, will be, in this case, to predict a random
experience (even algorithmic random experience): like WWMWWWMMMWM
...., for example. That is the first person indeterminacy.
It seems to me that, if I believe I am duplicable, and understand the
protocol, I must predict that I will experience being in both Moscow
and Washington. The process bifurcates one person, who becomes two
people with absolutely identical physique and memories immediately
afterwards, which will then begin to diverge. Both, looking back to
pre-bifurcation times, will say "that was me", and both will be
correct. There is no "essence" to be randomly (or non-randomly)
assigned to one location and not the other. The individual is now two
people and therefore can be and is in both cities.
You are right. That is why in more lengthy explanations I introduce
the key distinction between the first person points of view, and the
third person points of view.
For the simple case of self-duplication the first person account can
be defined by the content of a personal diary brought by the
candidate: which means that it will be read and cut itself and
reconstituted in both cities. Here the third person account is
provided by the memory, or the content of a diary of an external
observers, and is not going to be annihilated and reconstituted.
The indeterminacy bears on the first person experience(s). You are
read and cut in Helsinki, and reconstituted in W and M.
You are asked to predict where you will *feel* to be after the
duplication.
We suppose that you assume comp, and so you believe that you will
survive such duplication. We assume also that the correct level of
substitution has been chosen, and all the default assumptions (no
bugs, no asteroids demolishing a reconstitution machine, etc).
So you can predict, with this relative to comp certainty, that you
will survive, and that indeed, you will survive in both city. But comp
prevents the existence of some telepathy between the two copies. So
you know in advance that both of "you" (the M-you and the W-you) will
both *feel* to be in only one city.
One will write in his diary: "Oh, I see that I am in Washington and I
can only intellectually believe that I have a doppelganger in Moscow",
and the other will write "Oh, I see that I am in Moscow, and I can
only intellectually believe that I have a doppelganger in Washington".
So from both their first personal point of view, they get one bit of
information.
The indeterminacy comes from the fact that they cannot have predicted
in advance which one they will become, before the duplication.
If, in Helsinki the candidate predicts that he will feel to be in W,
the guy in M will rightly consider that he was wrong in his
prediction made before in Helsinki, and vice versa.
As you say yourself, bot copies shares their memory-life up to the
experience in Helsinki, and to evaluate their uncertainty, they have
to take into account all the future copies discourses.
If this is not clear, let me copy you a slightly more elaborate
account. It is called "step 3", because it is the step 3 of the
Universal Dovetailer Argument, which is the main argument showing the
reversal between physics and information/computer science following
the comp assumption. It takes into account preview critics similar to
what you said.
In fact you attribute your consciousness and identity to both copies
(it is a 3-person-view on the 1-person-view, but the indeterminacy is
on the 1-view themselves). You can say "tomorrow, you can join me in W
and in M". But from your personal perspective you get after the
duplication, you will feel to be one and entire in a well defined city
(W *or* M).
If you get this, don't read what follows. If it is still unclear, read
what follows, and if some questions remain, I will answer them here.
== UDA step 3 == (from the FOAR mailing list) == (
http://groups.google.com/group/foar?hl=en.)
I assume comp throughout, and, like in the two preceding steps, I
assume the supplementary "neurophilosophical hypothesis", according to
which the biological brain, the one in our skull, is the generalized
brain (= the portion of reality that we have to emulate digitally, at
some right description level, for your consciousness to be able to
relatively manifest itself.
The description, or substitution, level exists by the comp hypothesis.
So you have accepted, or are supposed to have accepted (tell me
otherwise) that you can survive with a digital brain (this is just a
rephrasing of the comp hypothesis, using the neuro hypothesis).
You have accepted, in UDA step one, a job on Mars, for which you need
to use a digital classical teleportation device, twice a day.
So you are read and cut on Earth and then, from the read (scanned)
information which is sent on Mars, you (your body) is reconstituted
there, at the right substitution level. Then you do your work on Mars,
and at the end of the afternoon, you come back on Earth, using the
same method.
No need to imagine that this can be done in practice. The reasoning
needs only to be possible in principle, or in theory. Actually, a
large part of UDA can be done with robots or programs instead of
humans, given that we have given purely third person definition of the
first person (personal memory) and third person (bodies encoding those
personal memories) notions. This means also we can derive a lot of
information by using the weaker "strong AI" thesis, or even the still
weaker Behavioral Mechanist thesis in the place of comp, but it is
more tedious to do so, and I continue to use comp.
Steps 1 (and 2), can also be considered as a clarification of the
meaning of comp, and does not introduce anything really new.
Step 3 is a bit more involved.
Like in step two, but more importantly, the key relies in the
understanding of the first and third person distinction.
Here is the protocol of step 3.
You (your body) are (is) read and cut (annihilated) in Helsinki (say).
But now the scanned digital information is sent (by radio-wave, say)
in two places: Washington and Moscow (to fix the things). We assume
that he is not reconstituted elsewhere.
In Helsinki, you are told the entire protocol in advance. So you know
that you will be read and cut in Helsinki, and that "you" , that is
the body, in the relevant state (which exists by comp) will be
reconstituted in both cities W and M.
Now we ask the following question to the candidate, in Helsinki. What
do you predict will happen to you, from the experiential, first
person, point of view. We ask "where will you feel to be?"
Let us imagine how the candidate can answer that question.
He might be a bit naive, and answer directly something like
"I will find myself in W and in M".
Well, that is not entirely incorrect. We can indeed join him, or a
version of him, in both cities. But then, we remind him/her that the
question, asked in Helsinki, before the split, was bearing about what
he will feel personally. His answer was bearing on him, as seen by
some external observer. So he agrees that his first answer was a bit
ambiguous, and he makes it more precise by saying:
"I will feel myself in W, and I will feel myself in M".
That is, again, not entirely incorrect, but still does not answer the
question. Here the candidate imagines the existence of the two
reconstituted bodies, made in each city, and he attributes them
consciousness and feeling, and the right, provided by comp, to assert
that they are "him" (they both do have the genuine memory of the
person who was in Helsinki).
Now, if only by definition, the personal first person account consists
in what will be written in the personal diary/memory. He will never
write "I feel myself now being in M and I feel myself now in W",
because the two bodies have become independent, and there are no
reason, (in our theretical comp frame) to expect some telepathy
between the two reconstituted persons.
So, he can know in advance in Helsinki (relatively to the comp
assumption), that in each copy of the diary, which he will take with
him in the read and cut box in Helsinki, and which will be duplicated
and reconstituted in W and M together with him, both the one in M and
the one in W will have to write something like:
I know myself to be in W (resp. M) and I believe intellectually that
there is another guy in M (resp. W), looking like me, and having the
same right as me to claim that he is the same person as the one in
Helsinki, despite I am not him, in the sense that right now, our
personal feeling are different.
Put more simply, he will write "I am in W and I have a doppelganger in
M", or "I am in M and I have a doppelganger in W".
Note that he cannot have any personal certainty that the doppelganger
has already been constituted. From there, he can only develop third
person belief about him.
The guy know all this in advance. He knows that if comp is true, he
will survive the duplication, and that, in all possible future
personal situation, he will feel to be in only one city, with an
inferred doppelganger in the other city.
So, if he is asked in Helsinki where he will feel to be, he can only
answer that he will feel to be in W or in M, but without being able to
be sure if he will feel to be in W or that he will feel to be in M.
Indeed, if he write in his diary that he is sure that he will feel
himself in to be in W, the copy in M, will have to admit that he was
wrong when in Helsinki (which belongs to his memory). And, by comp, he
is right about this. And vice versa, if he writes in Helsinki in his
diary that he is sure that he will be in M, then the copy in W will
have to admit he was wrong, when in Helsinki, as the question in
Helsinki bears on such personal future self-localization feeling.
So we (and him) can conclude that in Helsinki, the candidate cannot
predict with certainty what will the result of his self-localization
be experienced specifically, in the personal way, except for the
indetermination: Washington OR Moscow.
OK?
I hope I was not too long. I did take into account some critics
recently made.
Garry, if you are OK with this, feel free to write a shorter version.
I will certainly propose shorter version myself in some summary later,
but this version takes critics which have been already done into
account.
Any problem? Some variants of that experience can be given. The
impossibility of predicting exactly what we can feel in digital self-
duplication experiences is what I call "first person indeterminacy".
Like in Everett QM, the splitting, or differentiating, person cannot
feel the split (as he would not been able to immediately distinguish
this duplication experience with the one where we cheat on him, and
reconstituted him only in one city).
Feel free to make any comment, or ask any question, if you have any
difficulty with this. In some next post, we will have to say some
words about how to quantify such indeterminacy.
You might test your understanding by considering iteration, 64 times
say, of that experience, where both the W-guy and the M-guy come back
(by planes, say) to Helsinki, and redo that experience, and then again
and again.
Abbreviating "I feel myself to be in X" by "X", the 2^64 resulting
diaries will all contain a "memory/story" describable by a string of
length 64, and simple combinatory relations can show that most of them
will be random (even algorithmically incompressible, and more and more
so, relatively to the number of strings, as the number of iteration
grows).
Bruno
http://iridia.ulb.ac.be/~marchal/
--
Robin Faichney
<http://www.robinfaichney.org/>
http://iridia.ulb.ac.be/~marchal/
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