42 J.J.C. Smart
the theist in the search for some analogue of God’s necessity in that of math-
ematical existence.
Probably, therefore, the theist’s best bet might after all be to try to defend
the old fashioned form of mathematical Platonism, with its direct intuitions
of a super-sensible reality (universals), which exist eternally and in some sense
necessarily. If this sense of ‘necessarily’ could be made intelligible then God
might be said to exist necessarily in this sense. We are led into obscurities and
it is, as I have said, hard to fit Platonic intuitions into modern epistemology
and neurobiology.
When all is said, however, it might be best for the theist to say simply
‘God exists necessarily’ in the way that the number 23 does. Would this be
a sort of polytheism with many necessary beings? Or would 23 be somehow
part of God? I leave this question to theologians. The atheist will feel well
relieved of these intractable problems.
Eternity and SempiternityIn discussing the cosmological argument I took it that Aquinas was at his
best in thinking of God as eternal, in the sense of not being in time at all. In
this way the existence of God would be said to explain the existence of the
whole space–time world (as we think of it) without being an efficient cause at
the first moment of the universe’s existence, a concept which has no clear
sense in modern cosmology. As I noted, the universe can have a finite past
and yet have no unique first moment. Furthermore there is no unitary time.
The special theory of relativity tells us that there is no preferred set of axes in
Minkowski space. Still, perhaps a preferred set could be got by going outside
the theory, e.g. in preferring space–time axes with respect to which the cos-
mic background radiation is equal in all directions. Even so, because of the
expansion of the universe, these local times would lie in different space–time
directions from galaxy to galaxy. Also time-like world lines get bent up in
black holes (as at the beginning of the universe) and black holes may possibly
spawn baby universes with their own different space–times. We should there-
fore be cautious about talking of God as in time, sempiternal not eternal. In
what time would a sempiternal God be sempiternal in? These considerations
reinforce, in my mind at least, the interpretation of God’s eternity as atemporal
rather than sempiternal. In what follows I shall use ‘eternal’ in this atemporal
sense and shall contrast eternity with sempiternity.
William and Martha Kneale have explored the issue of eternity versus
sempiternity in two scholarly and instructive papers.^80 They bring out the
tensions in Aquinas’s thought. On the one hand Aquinas had a classically
inspired preference for the ‘eternal’ conception of God, which William Kneale
traces back to Parmenides and Plato, but not to Aristotle, who was on the