Big Bang as evidence of God

Don N Page (don@Phys.UAlberta.CA)
Wed, 17 Sep 97 11:29:41 -0600

I am aroused to comment on the Sept. 14 question by John P. McKiness
and Sept. 16 reply by Glenn Morton:

McKiness: "Think about it, is there any convincing, supporting
evidence for us in the late 20th century that God exists?"

Morton: "Yes. The Big Bang. If the universe were eternally past, then
God would be useless. Since the Big Bang requires a vacuum fluctuation, someone
needed to created the vacuum. A vacuum is not 'nothing', it is something."

Since being a cosmologist and former postdoc of Stephen Hawking has led
me to think about these questions. I should say that although I strongly agree
that "A vacuum is not 'nothing', it is something," in my opinion (apparently
not shared by certain others such as Hugh Ross and William Lane Craig), the Big
Bang is not significantly more evidence for the existence of God than many
other elegant cosmological models would be if they were instead supported by
the evidence. In other words, I reject the claim that a finite age of the
universe helps the cosmological argument that there is a Creator. And I
certainly do not accept the statement that "If the universe were eternally
past, then God would be useless." By faith I would still accept the conclusion
of the cosmological argument, that the existence of the universe depends upon a
Creator. (However, I would not, and do not, accept the cosmological argument
as a PROOF of the existence of God, since it seems logically possible, even if
perhaps implausible, that this universe could exist even if God did not,
whether or not this universe has a finite age.)

I know it is tempting to suppose that evidence for a finite age of the
universe is evidence that it was created, especially for Christians now that
the Big Bang theory has considerable scientific support. But I don't see that
this particular contingent fact (of finite age, if it is indeed a fact) about
the universe has any real relevance for the question of whether or not God
created it. God could just as well have created a universe with infinite age.
On the other hand, if a universe of infinite age could exist without God, I see
no reason why a universe of finite age could not also exist without God.

Besides its logical incorrectness (at least as I see it), the view that
God is needed if and only if the universe has finite age has the danger of
suggesting that God does not exist if and when a scientific theory is accepted
that says that after all the universe has infinite age. Andrei Linde's version
of stochastic inflation does actually suggest that the universe underwent an
infinite period of inflation (which is roughly exponential expansion, with the
linear size of the universe accelerating with time rather than decelerating)
before the present epoch of roughly power-law expansion in which the linear
size of the universe is presumably decelerating (unless there is a positive
cosmological constant, so that the universe began accelerating again in fairly
recent times). I'm not sure that a fully quantum theory of gravity (which we
do not have yet) would really have an infinite period of inflation, since it
seems likely to me that the concept of time would likely just break down at
some finite time in the past, but Linde might be right, and then this
(erroneous, in my mind) coupling of a finite age with createdness would just be
an embarrassment for Christians.

Another danger is the possibility of the correctness of theories such
as the Hartle-Hawking `no-boundary' proposal for the quantum state of the
universe, in which the quantum state is obtained by a path integral over
`Euclidean' four-geometries (in which time is taken to be imaginary in the
mathematical sense of having a negative square, so that all four dimensions are
effectively spatial) that have no boundary (other than the three-space, e.g.,
the universe configuration today, that is the argument of the quantum-theory
wavefunctional). As described at a popular level in _A Brief History of Time_,
these four-geometries, or Euclidean histories of the universe that make up the
path integral, have no precise initial times, so in a certain sense they have
no beginning (though they do not have an infinite age either, but rather time
loses its usually assumed character of being a real variable that runs along
the real line either from minus infinity or from a finite beginning). If the
creation of the universe is claimed to imply a beginning in time, then the
Hartle-Hawking proposal could be claimed to imply that the universe was not

Of course, this particular proposal is scientifically highly
controversial and is not even complete (since it requires that we have a
complete dynamical theory of everything, including quantum gravity, which we
certainly don't yet have), so it is surely not the last word on the subject.
Nevertheless, evidence such as the second law of thermodynamics strongly
suggests to me that the state of the universe, as well as the dynamical laws of
its evolution, are much, much simpler than they might have been, so some fairly
simple proposal for the quantum state of the universe, such as a more
sophisticated version of Hawking's proposal, might well be right. Thus it is
interesting to consider the implications of this particular proposal, even if
the truth turns out to be rather different.

As Hawking himself put it at the end of Chapter 8 of _A Brief History
of Time_, "So long as the universe had a beginning, we could suppose it had a
creator. But if the universe is really completely self-contained, having no
boundary or edge, it would have neither beginning nor end: it would simply be.
What place, then, for a creator?"

Actually, Hawking's argument is not quite the same as the erroneous
form of the cosmological argument that I have attacked above, which supposes
that a universe with a finite age needs a Creator but one with infinite age
does not. Instead, Hawking seems to argue that God is only needed to set
boundary conditions for the universe, to choose the actual state of the
universe from all the possible ones that evolve according to the same dynamical
laws. These would be needed in a classical spacetime with real time either if
it had an initial singularity (a Big Bang at a finite time in the past) or if
it had an infinite age and so no initial singularity. But as Hawking wrote 4.7
pages earlier (on page 136 in an early hardback printing), "On the other hand,
the quantum theory of gravity has opened up a new possibility, in which there
would be no boundary to space-time and so there would be no need to specify the
behavior at the boundary. There would be no singularities at which the laws of
science broke down and no edge of space-time at which one would have to appeal
to God or some new law to set the boundary conditions for space-time. One
could say: `the boundary condition of the universe is that it has no boundary.'
The universe would be completely self-contained and not affected by anything
outside itself. It would neither be created nor destroyed. It would just BE."

But as I wrote in my review of _A Brief History of Time_ in Nature,
Vol. 332, p. 742 (21 April 1988), "_A Brief History of Time_ provides Hawking
with an opportunity to present at first hand some of his own philosophical and
theological conclusions from the no-boundary proposal. After discussing what
he considers to be the most common view of God's activity --- that God started
off the Universe and then let it evolve without intervention --- Hawking
objects that if the Universe actually has no boundary, and hence no beginning,
`What place, then, for a creator?'. However, this objection does not apply to
the Judaeo-Christian view, that God creates and sustains the entire Universe
rather than just the beginning. Whether or not the Universe has a beginning
has no relavance to the question of its creation, just as whether an artist's
line has a beginning and and end, or instead forms a circle with no end, has no
relevance to the question of its being drawn.

"Of course, if the no-boundary proposal is correct, it does have
interesting implications for the beauty, elegance and simplicity of the
Universe God did create. Hawking draws the conclusion that God `had no freedom
at all to choose initial conditions', but this is debatable. When I was
defending Hawking's proposal to a small group of gravitational theorists in
1982, Bryce DeWitt expressed this view by saying, `You do not want to give God
any freedom at all'. However, Karel Kuchar quickly rejoined, `But that's His
choice'. In other words, even if we correctly hypothesize which state God
chose for the Universe, that would in no way eliminate the freedom He may have
had in making that choice. Choosing the no-boundary state and then actually
carrying out the immense task of the creation of the Universe in this state is
a far cry from Carl Sagan's claim in his introduction to the book of `nothing
for a Creator to do'."

Don Page
CIAR Cosmology and Gravitation Program and Department of Physics
University of Alberta