# RE: What gives philosophers a bad name?

```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. And the probability of finding oneself alive is 1 in

>> 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. But Bruno-Helsinki will experience each
outcome.

Whats missing here is a discussion about what conditions are required in order
to induce a feeling of subjective uncertainty in Bruno-Helsinki. 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.

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. 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.

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. This is why I say your analysis
violates the yes doctor axiom.

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. 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.

All the best

Date: Wed, 9 Oct 2013 15:36:12 -0700
From: meeke...@verizon.net
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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