All three of these arguments rely upon the idea of a regress and
invoke God to terminate it. They make the entirely unwarranted
assumption that God himself is immune to the regress. Even if we
allow the dubious luxury of arbitrarily conjuring up a terminator to
an infinite regress and giving it a name, simply because we need
one, there is absolutely no reason to endow that terminator with
any of the properties normally ascribed to God: omnipotence,
omniscience, goodness, creativity of design, to say nothing of such
human attributes as listening to prayers, forgiving sins and reading
innermost thoughts. Incidentally, it has not escaped the notice of logicians
that omniscience and omnipotence are mutually incompatible. If
God is omniscient, he must already know how he is going to intervene
to change the course of history using his omnipotence. But that means
he can't change his mind about his intervention, which means he is not
omnipotent. Karen Owens has captured this witty little paradox in
equally engaging verse:

Can omniscient God, who
Knows the future, find
The omnipotence to
Change His future mind?

To return to the infinite regress and the futility of invoking God
to terminate it, it is more parsimonious to conjure up, say, a 'big
bang singularity', or some other physical concept as yet unknown.
Calling it God is at best unhelpful and at worst perniciously misleading.
Edward Lear's Nonsense Recipe for Crumboblious Cutlets
invites us to 'Procure some strips of beef, and having cut them into
the smallest possible pieces, proceed to cut them still smaller, eight
or perhaps nine times.' Some regresses do reach a natural
terminator. Scientists used to wonder what would happen if you
could dissect, say, gold into the smallest possible pieces. Why
shouldn't you cut one of those pieces in half and produce an even
smaller smidgen of gold? The regress in this case is decisively
terminated by the atom. The smallest possible piece of gold is a
nucleus consisting of exactly seventy-nine protons and a slightly
larger number of neutrons, attended by a swarm of seventy-nine
electrons. If you 'cut' gold any further than the level of the single
atom, whatever else you get it is not gold. The atom provides a
natural terminator to the Crumboblious Cutlets type of regress. It
is by no means clear that God provides a natural terminator to the
regresses of Aquinas.
-Richard Dawkins, The God Delusion

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