36 J.J.C. Smart
outsideit also. If we proceed in an infinite regress in this way we are left with
an infinity of things which in aggregate still does not contain the reason for
its existence. Hence, Copleston argues, the explanation for the existence of
the universe must lie in some being ‘which contains within itself the reason
for its own existence’, which necessarilyexists.
Russell thinks that it is legitimate to ask why any particular event occurs by
giving its cause, and so on back indefinitely, but that it is illegitimate to ask
for an explanation of the whole infinite chain. This would indeed be so if all
explanations had to be in terms of cause and effect, but Copleston reasonably
asks why it is illegitimate to ask for an explanation of the whole chain. Such
an explanation cannot be causal, but why should all explanations be causal?
Could the existence of the universe as a space–time whole be explained by an
atemporal necessary being not itself in space or time?
A theologian, such as Aquinas at his best, need not be worried about
whether there was a first moment of time, at which God created the universe
just before the cosmic ‘big bang’. The universe might be finite in earlier time
(as cosmologists believe) and yet have no first moment. Time might be like
the set of real numbers greater than zero, of which there is no first number, or
even like the positive fractions...^1 / 32 ,^1 / 16 ,^1 / 8 ,^1 / 4 ,^1 / 2 , 1, 2,... Of course
cosmologists believe that in fact there is a much more sophisticated story to
be told about time, or rather space–time. The illustration is simply to show
how time could be finite towards the past, and yet there could be no first
moment. In the sort of model of the tiny compressed space–time with which
the universe began (less than 10−^33 cm radius) that James Hartle and Stephen
Hawking have produced, time-like world lines get bent into space-like direc-
tions, and even if each didhave a first moment there would be no unique
such. In any case ordinary notions of space–time break down within such a
singularity. Hawking has suggested that these considerations suggest that we
do not need belief in a creator God.^67 Aquinas would have had an answer to
this. Even if there were no first cause in a temporalsense, we would still want
to seek an atemporal explanation of the whole universe, past and future,
which would be in terms of an eternal God outside space and time.
Aquinas could have given a similar retort to the idea that the universe
could have come into existence through a quantum fluctuation. The idea is
now quite common, and there is talk of our universe spawning baby universes
outside our own space–time, perhaps from ‘black holes’. However, the idea
was put forward earlier in a simple way by Edward P. Tryon.^68 According to
Heisenberg’s uncertainty principle the energy and time of a system cannot
both be determinate. If ΔE is the uncertainty of the energy and Δt is the
uncertainty of the time, ΔE·Δt is of the order of magnitude of Planck’s
constanth and if energy is determinate t is infinitely indeterminate. So if the
energy is zero or near zero an infinite or a long-lived universe could have