Atheism and Theism JJ Haldane - Common Sense Atheism

18 J.J.C. Smart
on context. I mainly think of it in terms of coherence, of fitting the
explanandum proposition into our web of belief, 29 but in a scientific or
cosmological context at least we should explain the more particular by the
more general, the parochial by the cosmic. Whitrow’s argument does indeed
establish connections between the three dimensions of space and the existence
of intelligent life on earth. That space has three dimensions is shown to
be a necessary but not sufficient condition of the existence of inhabitable
planets and intelligent life.
Is it that explanations come from the giving of necessary conditions, not of
sufficient conditions? This will not do, because sometimes it is a sufficient
condition that is explanatory. Decapitation is a sufficient condition for the
death of Charles I and is explanatory of it. It is not a necessary condition for
his death, since he might have died in his bed or by shooting. A cause is
sufficient for an effect (given constancy in our contextual assumptions about
background states of affairs – e.g. putting a match to a fire causes it to flame,
assuming the presence of oxygen, that the wood is not wet, etc.) but is not
necessary (e.g. Charles I might have been simultaneously decapitated and
shot through the heart).
These complications make it difficult to say clearly and precisely just why
Whitrow’s putative explanation of the three-dimensionality of space is back
to front. I suspect that it is just a matter of the particularity of the suggested
explanans and of the cosmic nature of the supposed explanandum. Let us
consider an even more preposterous argument, also due to Whitrow. This is
that if space had only two dimensions we could not have any alimentary
canal, since we would be divided into two disconnected parts. However, is it
not mad to say that space has more than two dimensions because we can eat,
instead of saying that the cosmic fact that space has three dimensions is (in
part) the explanation of why we can eat?
Brandon Carter who first formulated the anthropic cosmological principle
(in fact both a ‘weak’ and a ‘strong’ version of it) did so in connection with
the hypothesis that our universe is only one of a huge variety of universes, a
‘world ensemble’, in which the fundamental constants of nature, which seem
so arbitrary to us, differ randomly from universe to universe. 30 Strictly speaking,
of course, ‘universe’ should refer to everything that there is (perhaps
excluding God if we talk of God creating the universe) and so could be
taken to refer not to what we think of as our universe but to the ensemble
of universes. However, I think that it will not be confusing if I use the
word ‘universe’ ambiguously and rely on context to make it clear whether
I am talking of one of the many members of the world ensemble or of the
whole lot.
Carter’s many universes hypothesis may be held to explain the fine tuning
of our universe. If there is a sufficiently large number of universes with the