Theism and Explanation - Appeared-to-Blogly

80 Theism and Explanation
low—that the facts we observe are extremely unlikely to have occurred by
chance. We also need to show that the likelihood that we should observe
the same facts is higher, given design. And to do this, we need to be able to
predict what would follow if the hypothesis were true.
I shall look at Sober’s claim that proposed explanations cannot win by
default later (7.1.3). I think it is true (6.2.2), although I am not convinced by
the particular arguments he offers. But his underlying point seems uncontroversial.
If we are to take a proposed explanation seriously, we must be
able to predict what would follow if it were true. Sober’s argument is that in
the case of a proposed theistic explanation this condition cannot be fulfi lled.
He formulates his objection in terms of testability: if one cannot say what
would (and would not) follow if a hypothesis were true, then that hypothesis
is untestable. But there is a prior and more important question. If Sober
is correct, the problem is not merely that the proposed theistic explanation
is not testable; we cannot know that it is even a potential explanation of the
fact in question. A potential explanation, I have argued (2.1.2), is one that
satisfi es the second premise of Peirce’s abductive schema.
(1) The surprising fact, E, is observed.
(2) But if H were true, E would be a matter of course.
(3) Hence, there is reason to suspect that H is true.
If we cannot know what would follow, given the truth of a theistic hypothesis,
then we cannot say whether it meets this condition. We do not know if
the explanandum is what we would expect, given the truth of the explanans.
If this were true, it would constitute a strong in principle objection to
all proposed explanations of this kind.
So on what grounds does Sober argue in support of what I am calling
“theological scepticism”? He argues that theists simply cannot specify how
their posited designer would be expected to act, in order to achieve his
goals. Why? Because to do so, writes Sober, would require
further assumptions about what the designer’s goals and abilities would
be, if he existed. Perhaps the designer would never build the vertebrate
eye [for example] with features F 1 . . . F n either because he would lack
the goals or would lack the ability. If so, the likelihood of the design hypothesis
is zero. On the other hand, perhaps the designer would want
to build the eye with features F 1 . . . F n and would be entirely competent
to bring this plan to fruition. If so, the likelihood of the design hypothesis
is unity. There are as many likelihoods as there are suppositions
concerning the goals and abilities of the putative designer. Which of
these, or which class of these, should we take seriously? 6
It is true, Sober concedes, that we can identify the products of human
design. But we can do so only because we know something of the goals and