On 16 Dec 2013, at 20:06, meekerdb wrote:
On 12/16/2013 12:37 AM, Bruno Marchal wrote:
On 15 Dec 2013, at 17:04, John Clark wrote:
On Sun, Dec 15, 2013 at 4:04 AM, Bruno Marchal <marc...@ulb.ac.be>
wrote:
>>> you know in Helsinki that you will survive and feel to be in
only one city with probability one
>> That depends, Is "You" the Helsinki Man or the Moscow Man or
the Washington Man or John K Clark?
> They are the same man, we have already discussed this
If they are all the same man then the Washington Man is the
Helsinki Man, thus the report from the Moscow Man that he sees
Moscow and only Moscow is insufficient information
Exactly. As I said, we can only have a 3p confirmation of the comp
1p-indeterminacy by tracking and interviewing all copies (or some
reasonable sample).
to judge the quality of the prediction about which cities the
Helsinki Man will see, you've got to hear what the Washington Man
has to say too if you want to know if the prediction was correct;
Yes. And in the step 3 case, both confirms they see only one city,
and that gives the complete information each of them have access
too in the first person way. They both confirms that they were
unable to predict the city with certainty.
not that the accuracy of predictions has anything to do endowing
us with a sense of self. And they are NOT all the same man, they
are all John K Clark but the Moscow Man is not the Washington Man.
Exact. That is the root of the indeterminacy. They are the same
man, but their history have irreversibly differentiated.
We agree on all this, but this explains the 1-indeterminacy.
> As I said you confuse "indeterminacy" (the general vague
concept) with the many different sort of indeterminacy:
1) by ignorance on initial conditions (example: the coin), that
is a 3p indeterminacy.
2) Turing form of indeterminacy (example: the halting problem),
that is again a 3p indeterminacy.
3) quantum indeterminacy in copenhague (3p indeterminacy, if that
exists)
4) quantum indeterminacy in Everett (1p indeterminacy, which
needs the quantum SWE assumption)
5) computationalist 1p-indeterminacy (similar to Everett, except
that it does not need to assume the SWE or Everett-QM). It is
the one we get in step 3, and it is part of the derivation of
physics from comp.
Only the first 3 make any sense, and even there all those peas are
unnecessary.
OK. But here, contrary to what you answered many times to Quentin,
you seem to agree that if your argument is valid again the comp-
indeterminacy, it is valid against Everett formulation of QM.
JKC makes a big point of the complete separation of quantum worlds,
although Everett didn't write about multiple worlds. Everett only
considered one world and wrote about the "relative state" of the
observer and the observed system. In some ways this is more
fundamental because in principle the "different worlds" of MWI can
interfere with one another. That they usually don't is a
statistical result.
I agree with you. But I discovered that Everett did talk on the many-
world, but was asked to use "relative state" instead. personal notes
of Everett seemed to acknowledge this.
The "worlds" or "quantum computation" can always interfere
statistically. Same in comp.
I recall you that, like Einstein and many others, I believe that
"3)" is "insanity". You might be right that it is logically
conceivable (perhaps---I am not even sure about that), but once we
accept events without cause, we fall in the "don't ask" type of
theories. As explanation, it is as bad as the God-of-the-gap.
I think that's an unfair criticism of Copenhagen. Deterministic
theories just push the problem back in time. Ultimately there is
either an uncaused event or an infinite past.
Or no time, or no primitive universe.
So there is not great intellectual virtue in rejecting uncaused
events.
By religious believer in a primitive universe. Keep in mind we don't
assume this in comp at all.
Quantum mechanics is an interesting intermediate case. It has
randomness, but randomness that is strictly limited and limited in
such a way that it produces the classical world at a statistical
level.
If you believe in the collapse, which is pure magic.
Your own theory also introduces uncaused events, namely the
computations of a universal dovetailer.
I disagree. with comp all events have a cause. The only assumption
"without cause" are
Logic +
0 ≠ s(x)
s(x) = s(y) -> x = y
x+0 = x
x+s(y) = s(x+y)
x*0=0
x*s(y)=(x*y)+x
or
equality theory +
Kxy = x
Sxyz = xz(yz)
But then we can explain that with less than such assumption, we cannot
prove there is a universal machine, so we have to assumed them (or
equivalent).
The whole idea of "everythingism" was inspired by QM, but QM itself
doesn't entail that everything happens. If you measure a variable
you only get eigenvalues of that variable - not every possible
value. If you measure it again you get the same eigenvalue again -
not any value.
I agree. I have never say that everything happens. All computations
exists, that's all.
On the contrary, self-duplication explains the appearance of such
indeterminacy, without adding any further assumptions.
Well, the existence of self-duplication, even via Everett, is a
further assumption.
Not at all. It is a theorem in the theories above. (cf the Dx = "xx"
method, which can be arithmetized).
Occam favors it. Your belief in "3)" substitutes a very simple
explanation by a call to a form of built-in-non-explainable magic.
No more magic than a UD.
The UD exists in the same sense than 3 exists, and that is the usual
interpretation of Ex(x = s(s(s(0)))).
Bruno
http://iridia.ulb.ac.be/~marchal/
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