Theism and Explanation - Appeared-to-Blogly

96 Theism and Explanation
already cited David Hume’s suggestion that “our line is too short to fathom
such immense abysses” 47 [5.1].) But from the fact that our ability to make
such judgements is limited, it does not follow that we have no ability at all.
One could accept van Inwagen’s arguments, but argue that they support
nothing more than a moderate modal scepticism. However, for the sake
of the argument let me concede the modal sceptic his point. Let’s say that
we cannot claim modal knowledge in matters “remote from the practical
business of everyday life.” (There is presumably some point on the remoteness
scale where such judgements become unreliable. Let’s assume we can
specify what that is, so that—in true Socratic manner—we can know what
we do not know.) What would follow? What I want to suggest is that a
consistent modal scepticism has some devastating consequences.
A fi rst result of adopting a consistent modal scepticism is that the theist
could no longer appeal to the doctrine of divine omnipotence. Divine
omnipotence is commonly defi ned as the ability to do whatever is logically
possible. But what happens to this doctrine if we cannot know what is logically
possible? Worse still, what happens if the very category of the logically
possible is empty? 48 In this case, the doctrine of divine omnipotence is
also empty. It has no content at all. So one wonders how far van Inwagen
wants his modal scepticism to be taken.
A second, related consequence has to do with the issue at hand. For when
modal scepticism becomes theological scepticism, it constitutes a powerful
in principle objection to theistic explanations. I have argued that to offer a
potential theistic explanation is to posit an particular divine intention and
to argue that the explanan dum is how we would expect God to act, given
that intention. But of course it is precisely our ability to make such judgements
that the modal sceptic denies. It follows that, given modal scepticism,
a proposed theistic explanation could not be regarded as even a potential
explanation, of any fact at all. And if (per impossibile) it did establish itself
as a potential explanation, it would suffer from the fl aw of being entirely
ad hoc. There is no way it could be tested, for to test such an explanation
is to ask what else would follow, if it were true. (These are precisely the
arguments which Elliot Sober deploys, to which modal scepticism would
give new force.) So an atheist might welcome a thoroughgoing modal scepticism.
It would be nothing less than the “silver bullet” the atheist seeks.
5.4.4 Intelligent Design is Not Optimal Design
I shall conclude this discussion with an objection to suboptimality arguments
that has recently been articulated by William Dembski, a leading
fi gure in the “intelligent design” movement. Dembski repeats some of the
objections to the idea of “optimal design” which I have discussed above.
He then notes (somewhat disingenuously) that “taken strictly as a scientifi
c theory, intelligent design refuses to speculate about the nature of the