My phrase "something from nothing" was not meant
to restrict my inquiry to origins, in the sense of time or causality,
but can be viewed in terms of information in general.
It seems that the discussion has not contradicted my initial idea that,
when it comes to explaining why things are the way they are,
the multiverse is on the same level playing field as one universe.
Hal Finney simply states that this is not true without supporting it:
[The multiverse + AP is]
a very different kind of argument than you get with a single
universe model. Anthropic reasoning is only explanatory if you assume
the
actual existence of an ensemble of universes, as multiverse models do.
The multiverse therefore elevates anthropic reasoning from something of
a tautology, a form of circular reasoning, up to an actual explanatory
principle that has real value in helping us understand why the world is
as we see it.
I believe that my statement before:
...simply bringing in the hypothetical set of all unobservable things
doesn't explain rationally in any way (deeper than our direct
experience) the existence of observable things.
applies to the multiverse as well, since
the multiverse = observable things + unobservable things
and equivalently
the multiverse = this universe + unobservable things
I believe my reasoning applies to all selection principles,
not just the AP.
Also, Bruno wrote:
I think we should not confuse the problem of the selection
of a (apparant) universe/history from the assumption of a
multiverse (like the quantum hypothesis) with the question
of explaining the appearances of a multiverse itself. Godelian
self-reference can explain both from numbers and their
nameable and unameable relations....
A physical theory is a set of rules which remains invariant
for the transformations allowed in a multiverse. And comp
or its generalization makes our apparent multiverse the result
of the interference of the possible (with respect the the
comp hyp chosen) multiverses.
I see the problem of explaining what the multiverse is in the
first place (Bruno's second problem) as covered by my inquiry.
Selecting a smaller "initial" multiverse from the set of all possible
multiverses (or that could be The Multiverse) is equally an
unsupportable selection process, outside of the realm of
rationality. So Bruno claims to be able to explain it. So far I
haven't been satisfied with his UDA. It seems that his
assumptions restrict the multiverse in an equally unsupported
way. It must be a "necessary" premise, equal in validity
to the premise of just one universe, or
"what we see is what we get".
Tom
