Along with evolution, the multiverse is regarded by many as
a way for science to remove the need for God.
Both evolution and multiverse theory are viable theories and neither one
should just be dismissed simply because they seem to contradict the Christian
world view; this dismissal unnecessarily alienates a large proportion of
society from the truth of Christianity. As almost all scientific research in the
last 100 years has shown, the more we understand God’s creation, the more that
creation points us to God. Research into the multiverse actually strengthens
apologetic arguments for the Christian faith.
I am using Who’s Afraid of the
Multiverse by Jeff Zweerink as an outline and the main reference for this
article.[1]
Some basic background is necessary to understand why a
multiverse has been proposed. First,
there is a limit to how much of the universe we can directly observe. We can
only “see” the parts of the universe from which light has had time to come to
us. As time goes by, more light will
make it to earth, so we will be able to see more and more of the distant
universe. At the same time, however, the
amount of matter and energy in the portion of the universe we can observe will
shrink once the expansion rate of the universe exceeds the speed of light. So,
while we will be able to increasingly detect more of the universe, the density
of what we will be able to detect will actually decrease. The crucial point
here is that space does not end at the edge of what we can observe and we will
never directly detect anything beyond that edge.
Second, it is generally accepted that the universe is exceedingly
fine-tuned for life to exist on earth. (There
has already been much written on this; if you need more of an explanation, go here
and here.)
Third, there is an abundance of evidence that the universe
experienced a brief period of hyperinflation very early in its history. This
rapid, early expansion of the universe is necessary to explain why we observe the
universe to be uniform in every direction.
The hyperfast expansion at the start of the universe takes small regions
with the same temperature and expands them to a size comparable with the
observable universe. Inflation is also necessary to show why the universe has close
to a flat geometry. A simple definition
of “flat” means that two parallel beams of light remain separated by the same
distance regardless of how far they travel. Inflation is also necessary to
explain why we don’t see a multitude of cosmic defects (like magnetic
monopoles) as the universe cools. Go here
to read about a recent measurement that supports inflation.
Lastly, the possibility of many different universes
naturally arises from the most popular unification model. “Unification” has
been a major goal of physics ever since Isaac Newton. Newton showed that the forces we experience
on earth are the same as the forces in the heavens; unifying the heavens and
the earth. Since then, we have been able
to show that electricity, magnetism, light, and the forces that exist inside
the atom can all be explained with the same theoretical framework; namely
quantum mechanics. Gravity, the lone
hold out to this unification process, has proven incompatible with quantum
mechanics. String theory is the most
successful and popular theory that attempts to unify general relativity
(gravity) and quantum mechanics. What
comes out of string theory, though, is a potentially enormous number of
different universes with possibly different laws of physics.
Multiverse theory comes from these four major pieces of
evidence (the universe is larger than what we can detect, fine tuning, inflation,
string theory). Just like the word evolution,
the term multiverse has several meanings. While a multiverse always involves regions beyond
what we can observe, the MIT physicist Max Tegmark has classified multiverse
models into four levels.
The first type of multiverse is uncontroversial and has good
evidence for its existence. A “Level 1
Multiverse” simply means that the universe is larger than what we can see;
there are parts of our universe that are not directly observable. Inflation implies the existence of a level 1
multiverse. The only unknown with the level 1 multiverse is its size.
A “Level 2 Multiverse” is one in which other universes
exist, each with different laws of physics.
This is what most scientists are referring to when they use the term
multiverse. Evidence for a level 2 multiverse also comes from inflation, but
with the added observation that when the hyperinflation period stopped, things
would have to be exceedingly fine-tuned for all parts of the universe to stop expanding
in the same manner; giving us the uniformity we observe in the universe.
Mathematical calculations to “fix” this problem of the extreme fine-tuning give
the possibility of many “bubble universes” forming; the vast majority of these
having different physical laws from ours.
The fine-tuning we observe in our universe can be explained as simply a “selection
effect” – meaning that we just happen to be in the one lucky universe where the
physical laws match those necessary for life.
A level 2 multiverse requires a particular theoretical understanding of
inflation for which there is almost no observational or experimental evidence.
One interpretation of quantum mechanics describes the “Level
3 Multiverse.” Simply stated, this model describes parallel universes arising
from quantum uncertainty and probabilities and from the concepts of decoherence
and unitarity. Quantum mechanics is
described very well in mathematical terms, but how this mathematical description
is to be interpreted is still a matter of great debate. No specific
observational evidence exists that specifically points to this interpretation of
quantum mechanics; parallel universes instead are a philosophical preference of
one interpretation over another.
An infinite number of universes describes a “Level 4
Multiverse.” This, I believe, is what most people are thinking of when they
think of a multiverse. This also explains the fine-tuning we see in the same
manner as the level 2 multiverse. There is currently no observational evidence
to help us decide whether an infinite number of universes exist, but the larger
problem with an infinite number of universes is that it would explain too
much! An infinite number of universes
means that anything could be explained away by using the selection effect; in
such a model every possible situation - no matter how improbable - occurs
somewhere, so on what basis would science itself operate?
Here is a selection of Dr. Zweerink’s conclusions (all taken
from Who’s Afraid of the Multiverse) from
his work with multiverse models:
A large proportion of the scientific
community disagrees with or simply does not support multiverse theories. Some scientists argue that these models are
unscientific because they offer no testable predictions. Others contend that simpler solutions explain
fine-tuning without invoking the existence of completely separate universes
that, by definition, forever lie beyond scientists’ ability to detect.
In a Christian context, the apologists
battle does not directly concern the supposed or actual existence of the multiverse.
Instead, it is the naturalist’s claim that the multiverse provides an adequate,
comprehensive, and consistent explanation for humanity’s existence here on
Earth without the need of a supernatural Designer.
Whether the multiverse proves true or
false substantially affects none of the fundamental Christian doctrines.
At first glance, the multiverse theory
seems to effectively buttress the human “selection effect” explanation for the
fine-tuned appearance of our universe. Yet as research into multiverse
scenarios advances, it appears that they may simply move the design “up one
level.” In other words, instead of just one universe requiring fine-tuning to
support life, it appears that any multiverse-generating mechanism also requires
a high degree of fine-tuning to reproduce the observable universe in which we
live.
Go here to watch a recent
lecture by Dr. Zweerink regarding the multiverse.
