MU/MW (was Re: The neutrino has mass?!)

David Bowman (
Fri, 12 Jun 1998 12:35:08 EDT

Concerning John Rylander's earlier question about "many worlds", MW,
theories (or interpretations of quantum mechanics), and other "many
universes", MU, cosmologies I thought Loren Haarsma's answer was good.
Even though such theories (shear wild speculations is more like it) seem
to be minority views among the community of physicists, they do seem to
be growing in popularity (and more influential physicists are publicly
coming out in favor of them and may actually be the majority view for
those working in the fields of cosmology, superstrings, other unified
theories of everything, etc). For cases in point, witness the
all-physical-laws MW/MU hypothesis of Max Tegmark recently reported on by
Steve Jones and the MU thesis defended by Linde at the Berkeley
conference reported on by John Rylander. This increased popularity can
*not* be due to any new accumulating physical evidence for them, since a
cosmology that posits many unobservable universes will, by definition,
not leave any observable physical evidence for any of the universes other
than our own. I suppose there are at least 3 reasons for this increased
interest in MU cosmological theories and MW quantum interpretations.

First, it seems that MU cosmologies would be naturally attractive to
those with an a priori atheistic religious philosophy given the strong
evidence that our universe began at a finite time in the past, and that
it seems to have many constants of nature very finely tuned for it to be
compatible with our existence. With the demise of the steady-state and
the oscillating universe cosmologies, it seems that the varieties of MU
senarios may be the only game in town for a cosmology that is eternal
(for the ensemble of all universes--even if the individual universes may
be finitely lived) and such that our particular existence does not have
any special deep significance.

Second, it may be a case of scientists trying to use a MN theoretical
approach to fill in the gaps of scientific/naturalistic understanding in
as many realms of inquiry as possible. According to our best scientific
observations, the universe seems to have had a beginning in the past, and
according to our best accepted theory (General Relativity) for
understanding the nature of space and time, it seems that at the initial
"creation" event of the Big Bang (BB) the equations go singular and break
down and forbid us from acquiring any scientific understanding of this
event from our normal theories. Since scientists, qua scientists,
naturally don't like to be confronted with boundaries beyond which they
are asked not to go with their analysis and theories, their inclination
is to try to extend their theories in a way that *will* allow a
naturalistic treatment which crosses the boundaries indicated by the
earlier theories. Thus theories which have the universe popping into
existence as one of many quantum fluctuations from a pre-spacetime
substrate (i.e. a physical substrate that has no space, time or matter of
its own--yet is subject to a version of natural law) allow the BB
creation event to be conceived of and analyzed in a naturalistic manner,
and appropriately generalized quantum laws of nature can be imagined
which allows the creation event to be an inevitable outworking of those
laws and which boil down to the normally accepted laws of nature on the
larger length/time scales of our particular universe subsequent to the

Third, concerning the interpretations of quantum mechanics, those
interpretations that do not posit many worlds (or an initial one
ever-splitting into more of them) tend to have the problem of the
so-called "collapse of the wave function" that yields the probabilities
for the possible outcomes of measurement-type events (or of observations
or state preparations) involving an interaction between the system under
study and an *external* "observer" or measurement context. This puts the
role of the observer, measurer, experimenter right into the very
equations describing the laws of nature. If one is trying to extend
quantum theory in a way that subsumes general relativity and is a
descriptive theory of everything including the universe as a whole and
all the observers that it contains, then the only way the theory can be
"self-contained" is for it to not include references to observations
from the outside. The normal Copenhagen and related interpretations of
quantum mechanics will not allow for such a self-contained theory. The
MW interpretations *do* allow this, but at the prodigal expense of
positing enough worlds to insure the ontological reality of all possible
outcomes of all possible events--all with the correct frequencies
predicted by the quantum probabilities.

Regarding this last reason, I would prefer to turn the argument around.
I would like to suggest that the huge maximal violation of Occam's razor
necessitated by a MW interpretation along with the posited
unobservability of those worlds constitute an esthetic warrant for
rejecting such a MW interpretation. This means we end up with a theory
involving only our own obervable world, but this also means our
interpretation of quantum mechanics reserves a fundamental role of an
(at least one) outside observer/state preparer. Guess Who I would
suggest that is? Essentially it is the Divine Creator/Sustainer that
gets to pick the outcomes of all measurement-type events that collapse
quantum wave functions (but tends to pick them according to the
probability distributions specified by quantum theory, presumably as a
reflection of His divine faithfulness). I would also suggest that the
real outcomes of such picks tend to give the universe a continuously
created and sustained ontological existence rather than to allow it to
devolve into a myriad mess of less than actual potentialities.

David Bowman