On 15 Jul 2016, at 04:00, Bruce Kellett wrote:
On 15/07/2016 12:38 am, Bruno Marchal wrote:
On 14 Jul 2016, at 02:11, Bruce Kellett wrote:
On 13/07/2016 11:36 pm, Bruno Marchal wrote:
On 11 Jul 2016, at 13:49, Bruce Kellett wrote:
On 11/07/2016 9:31 pm, Bruno Marchal wrote:
Holiday Exercise:
A guy undergoes the Washington Moscow duplication, starting
again from Helsinki.
Then in Moscow, but not in Washington, he (the one in Moscow
of course) undergoes a similar Sidney-Beijing duplication.
I write P(H->M) the probability in H to get M.
In Helsinki, he tries to evaluate his chance to get Sidney.
With one reasoning, he (the H-guy) thinks that P(H-M) = 1/2,
and that P(M-S) = 1/2, and so conclude (multiplication of
independent probability) that P(H-S) = 1/2 * 1/2 = 1/4.
But with another reasoning, he thinks that the duplications
give globally a triplication, leading eventually to a copy in
W, a copy in S and a copy in B, and so, directly conclude P(H-
S) = 1/3.
So, is it 1/4 or 1/3 ?
Neither. The probability that the guy starting from Helsinki
gets to Sydney is unity.
Try to convince the guy who gets to Beijing, or the one who
stayed in Washington. He knows that the probability evaluated in
Helsinki was not P(Sidney) = 1.
We start with John Clark in Helsinki, so P(JC ~ H) = 1. By
construction, after the duplication and so on, P(JC ~ W) = P(JC ~
S) = P(JC ~ B) = 1. (I use '~' as a shorthand for 'in' or 'sees'.)
In the 3-1 view, that is correct.
There is no such thing as "the 3-1 view" distinct from the first
person view. That is just a piece of jargon that you made up to
cover the fact that you have assumed a distinction where none exists.
Of course there is. In the 3-1 view, we can say JC survived, and feel
unique, in both cities. But when the question is about the 1-view
expected by the H-guy, the answer is unambiguously "in W or in M, as I
know in advance that both copies will fell unique and like getting one
bit of information".
But in my posts I insist that "W", "M" denotes the experience of
opening the door or the reconstitution box, and writting in the
personal diary which cities is seen. In that case, obviously, P(W),
P(S) and P(B) cannot be all equal to one as W, S and B are
incompatible event.
These are not incompatible events: there are three physical bodies,
one in each city.
These are incompatible *experience*. These are incompatible for
describing the 1-views. It is obvious that all copies will say "one
city". And, well, the question was about that unique city that all 1-
views will confirm as being "only one city".
You seem to eliminate the 1-views, and be on the eliminativist slope.
Your definition of personal identity depends only on memories
(backed up by personal diaries if necessary).
Exact.
With this definition, and the protocol described, the bodies in W,
S, and B are all the same person.
That is ambiguous. They are all THE same person AS THE H-GUY, but of
course the HM-guy and the WM guy have become different from each
other, despite being both THE H-guy. Identity in modal context does
not obey Leibniz identity rule.
So it is JC who sees W, JC who sees S, and JC who sees B.
Yes, but not at once, as seeing (from the 1p view) W and seeing S, and
seeing B, are INCOMPATIBLE 1p experiences.
They are all the same person, so the correct prediction is that JC
will see all three cities.
In the 3-1 view. But that would be obviously contradicted by all the 1-
views, which was what we were predicting.
If you now introduce a difference between the copies, then they
become different persons, and the correct prediction would be that
JC (who sees H) will see no further cities because he no longer
exists.
The H-guy knows that both the W and M guys will be version of the H-
guy having survived two teleportation experiences, and that those
experiences will be incompatible *experiences*.
JC in Helsinki knows the protocol, so he can easily see that these
are the correct probabilities. So, as I said, the probability that
the guy starting from Helsinki gets to Sydney is unity. Any other
interpretation of this scenario involves an implicit appeal to
dualism -- there is "one true JC" that goes through these
duplications, and he can only ever end up in just one place.
Not at all. By comp we agree that they are all the true JC, and
that they all see, taken together, all cities. But the question is
about the personal events lived by the H-guy after he will push the
button, and that makes the events (1p-events) incompatible.
As I said above, the events are not incompatible. You are relying on
an intuition formed in a world without person duplication.
We duplicate since we are amoebas. The sexual reproduction has just
add some shuffling in evolution. And, if I introduced those
duplication, it was for people understanding that a 3-1 AND becomes a
1-1 OR. It is obvious to make the verification.
Yourclaim that they are incompatible relies on an implicit dualism
-- there is only one "true" JKC.
There is only one "lived" JKC, from all the 1-views possibly
accessible from Helsinki. When he (the one in W, or the one in M) opens
the door, in all cases, JKC will see only one city, and he knew that
in advance in Helsinki.
You confuse "events" (a 3p notion, or 3-1 notion) with
"experience" (which is a 1p notions, or 1-1p notion).
As John Clark has correctly pointed out, your intuition and
formalism simply does not work in the presence of person-
duplicating machines.
It works very well, but you need to distinguish between the
outsider view: all JC see all cities, and each personal views
obtained, which are incompatible.
You simply borrox John Clark confusion between the 3-1 views and
the 1-views.
There is no such thing as the 3-1 view --
Of course there is a 3-1 view. It a 3p views on bodies on which we
associate a (singular for each) 1p view.
that is just a piece of jargon invented to save your argument. It
does not correspond to any true distinction.
That is trivially refuted by the interview on all copies.
There is no single 1p view -- there are three possible 1p views in
the triplication scenario.
Right. The point is that from the first person perspective, those 1-
views are logically incompatible.
No they are not. They all refer to the experience of John Clark, as
defined by you.
Not at all. My definition, accepted by JKC, makes the M and the W-guy
both equal to the H-guy, but different between each other. In this
context of person, a =: b & a =: c does not entail that b =: c, with
"=:" read as "becomes". That is well known about modalities.
So, again, John Clark is right when he says that JC ~ H will see
three cities (W, S, and B) after the experiment is completed.
yes, he is right, but only on the 3-1 view on those 1-views, not on
the 1-views seen by the 1-views, which are incopatible, and which
was what the prediction asked was all about.
See above. I think you have given the correct explanation in one of
your replies to John Clark:
"We have testimony from John Clark that John Clark saw Moscow and
not Washington, and that John Clark saw Washington and not Moscow,
and by computationalism, those experience cannot be lived together,
and both John Clark have differentiated into different person,
despite being the same old Helsinki guy. We have the testimony from
both John Clark that they got one bit of information."
The crucial point in what you say here is that John Clark from
Helsinki has differentiated into different persons. But you then
contradict this by claiming that they are still the same person
("the same old Helsinki guy"). So your position is clearly
incoherent, they can't be both the same person and yet be different
persons.
Why?
Actually, the insight that, despite the copying process, different
persons have been created, is the key to unravelling all the
confusion that this issue has generated. It is your base theory of
personal identity that has been shown to be inadequate. The closest
continuer theory, with new persons in the case of ties, is the
theory best able to cope with all of this.
Then tell me which is closer then. W or M? But that step 3 is supposed
to be symmetrical, so there is no closer continuer. You need step 4
for discussing what happens when we introduce an assymetrical delay,
but then, by step 2, we know that such a dysymmetry cannot change the
1-views, so ...
If, as you claim, he will see only one city, you have to have some
dualist 'nut or core' that survives in only one of your copies.
Of course not. Just do the tought experience, and consider all 1-
views, as seen from each of them.
Do you agree that if you are promised a cup of coffee in both W and
in M, you can bet in Helsinki that you will get a cup of coffee
with certainty? if yes, it is the same for the question "how many
city will the H-guy seen, from its personal pov, after pushing the
button?". The answer is "only one city", or "I will drink a cup of
cofffe in ONE city with P = one, but I cannot know which one".
Of course, as I said some time ago, the easiest resolution of you
logical conundrums is that JC ~ H does not survive, and that there
are three new persons, one in each city, so the probability that
JC in H will see Sydney is exactly zero.
Then you predict that you will not survive either with a simple
(non-duplicating) teleportation, or with a brain transplant, and we
die ar each instant. That is OK (G and G* concures, but again, it
is in a 3p picture, contradicted by the 1-views, boith intuitively,
and mathematically.
How contradicted mathematically? It is quite a common view among
philosophers of mind that a new person is created in teleportation
(Captain Kirk in 'Star Trek' is killed and replaced by a copy when
teleported). This is not an incoherent view, so you can't just
assert that your view is the only correct one. One can survive very
well without assuming computationalism.
That does not make sense. Computationalism *is* the assumption that we
survive such teleportation.
But we cannot see both city at once, and so no diaries will ever
contain "I see W and I see M". Only the prediction "W v M" is verified
by the two first person views available. Computationalism entails the
first person indeterminacy. In W you know that you are in W, but have
only an intellectual knowledge that you have a doppelganger in M, and
vice-versa.
Bruno
Bruce
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