On 10 Oct 2013, at 03:25, chris peck wrote:
Hi Bruno
>> I don't see why. There is a chance of 1/2 to feel oneself in M,
and of 1/2 to feel oneself in W, but the probability is 1 (assuming
comp, the protocol, etc.) to find oneself alive.
This begs the question.
You make a quote out of the context.
And the probability of finding oneself alive is 1 in both your view
and mine.
Good. So it is one that he stay alive, and so it can only be one halve
that it will be W, or M. The copies are numerically identical, P(M) =
P(W), and so 1/2 is the only solution.
>> P(W v M) = P(W) + P(M) as W and M are disjoint incompatible
(first person) events.
That they are disjoint is fine. And they are incompatible only
insofar as no person, Bruno-Helsinki, Bruno-Washington or Bruno-
Moscow, in the experiment will experience both simultaneously.
OK.
But Bruno-Helsinki will experience each outcome.
How could that ever be possible?
"experience" is taken in the first person pint of view, and they can
be only W, or M, not both. You need some telepathy, or you need
another protocol.
In the 3p view, you are right, but that was not the question asked.
Whats missing here is a discussion about what conditions are
required in order to induce a feeling of subjective uncertainty in
Bruno-Helsinki.
The 1p-indeterminacy is objective and has nothing to do with a
feeling. It is obtained by a reasoning.
I think what is required is some ignorance over the details of the
situation, but there are none. Bruno-Helsinki knows all there is to
know about the situation that is relevant.
Yes, indeed, that is what is revolutionary (forgetting the MWI). We
are in a context where we have all the information, and yet cannot
predict an elementary outcome. It shows that determinacy entails
objective first person indeterminacies (objective because 3p-
communicable).
The same can be said for Everett QM, accepting to interpret a self-
superposition as a sort of self-duplication, or self-differentiation.
He knows that in his future there will be two 'copies' of him; one
in Moscow, one in Washington. By 'yes doctor' he knows that both
these 'copies' are related to him in a manner that preserves
identity in exactly the same way. There will be no sense in which
Bruno-Washington is more Bruno-Helsinki than Bruno-Moscow.
All this made my point. I agree.
That is the essence of 'yes doctor'. So, at the point in time when
Bruno-Helsinki is asked what he expects to see, there are no other
relevant facts. Consequently there is no room for subjective
uncertainty.
But there is still an objective indeterminacy. By reasoning alone, we
can see that only "W V M, but I don't know which one" will always be
confirmed, and anything more precise will be refuted by some copies.
It would therefore be absurd of Bruno-Helsinki to assign a
probability of 50% to either outcome. It would be like saying only
one of the future Bruno's shares a relationship of identity with him.
But that has to be the case from the future points of view. Like John
Clark, you seem to pursue the thought experiment at the first person
perspective after the duplication.
This is why I say your analysis violates the yes doctor axiom.
? (see just above).
This can be contrasted with a response from either of the copies
when asked the same question. If asked before opening their eyes,
both Bruno-Washington and Bruno-Moscow are ignorant of their location.
OK. The duplication is responsible for that ignorance. The helsinki
man know that on advance, and so, knows in advance that he will not
been abale to know his location before opening his eyes. You can add
the principle that if I know in advance that I will be confronted to
an uncertainty, then I am right now uncertain. In some lengthier
explanation, I add principles like that, but they are confusing for
most, so I delete such type of (too much obvious) principle.
Ofcourse, apart from the fact that asking the question at this point
is far too late for Bruno-Helsinki, this is not a relevent fact for
him. Because he has no doubt that an identity maintaining version of
him will be in each location.
I have to admit, what with you being a professor and all that, I did
begin to feel like I was going mad. Luckily, the other day I found a
paper by Hillary Greaves "Understanding Deutcsh's Probability in a
Deterministic Multiverse". Section 4.1 discusses subjective
uncertainty in a generalized setting and argues for the exact same
conclusions I have been reaching just intuitively. This doesn't make
either of us right or wrong, but it gives me confidence to know that
subjective uncertainty is not a foregone conclusion as I sometimes
have felt it has been presented on this list. It is an analysis that
has been peer reviewed and deemed worthy of publishing and warrants
more than the hand waving scoffs some academics here have been
offering.
I prefer avoiding authoritative arguments. Yet, as you mention this,
my PhD thesis has been peer-reviewed by three juries, and the
scientific members of those juries have all declare not having seen
any errors.
Only literary continental philosophers have problems, but they refer
explicitly to personal convictions, without any further ado. Some
scientists seem to defend those philosophers for reason which seems to
be academical solidarity (or worst, but that's beyond our topic).
Anyway, it is preferable to get the point by oneself, and not rely on
any authority, as we live in a lasting era where many people identify
science with Aristotle theology.
Best,
Bruno
All the best
Date: Wed, 9 Oct 2013 15:36:12 -0700
From: meeke...@verizon.net
To: everything-list@googlegroups.com
Subject: Re: What gives philosophers a bad name?
On 10/9/2013 10:35 AM, John Clark wrote:
On Tue, Oct 8, 2013 at 1:19 PM, meekerdb <meeke...@verizon.net> wrote:
> How do you explain quantum mechanical probabilities in the Many
Worlds interpretation?
Not very well, assigning probabilities is unquestionably the weakest
part of the Many Worlds theory. True, Everett derived the Born Rule
from his ideas, but not in a way that feels entirely satisfactory,
not that its competitors can do better. The Many Worlds
interpretation is the best bad explanation of why Quantum Mechanics
works.
So you recognize that it has the same difficulties with probability
and personal identity as Bruno's teleportation.
Brent
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