Theism and Explanation - Appeared-to-Blogly

Successful Theistic Explanations 121
But does this mean that just any known fact could corroborate a theory,
given that it is an observed consequence of that theory? This view—the idea
that any positive case of a hypothesis would corroborate it 14 —is sometimes
referred to as “Nicod’s criterion” (named after the logician Jean George
Pierre Nicod [1893–1924]). But if Popper’s criterion is too restrictive,
Nicod’s criterion, without further qualifi cation, is too permissive. Firstly, it
would allow corroboration by observed facts that differ from one another
in ways that are irrelevant to the hypothesis being tested. 15 Secondly, it
would allow a hypothesis to be corroborated by citing further instances of
the same phenomenon we are seeking to explain. And thirdly, it leads to
Carl Hempel’s notorious “raven paradox.” 16 So this criterion needs to be
tightened up a little.
A heuristic account. There are a number of ways in which one might
tighten up Nicod’s criterion. The fi rst is John Worrall’s “heuristic view” of
corroboration: the idea that the facts that are considered to corroborate a
theory should not be those that were used to construct it. 17 There is much
to be said for this view, which would at least help to eliminate the accumulation
of irrelevant instances. A theory cannot be corroborated by citing
further instances of the phenomena of the type it was devised to explain;
it can be corroborated only by citing other kinds of facts. But this view,
too, faces diffi culties. The fi rst is that of deciding which facts were used
in the construction of a theory, which is by no means as simple a task as it
might appear. 18 And the heuristic view does not avoid the raven paradox, 19
which Popper’s original view has the virtue of solving. (If background
knowledge already “predicts” that my yellow cup is a non-black non-raven,
then observing the cup cannot count as a severe test of the theory that “all
ravens are black.” 20 )
An historical account. There is, however, a second way of tightening up
Nicod’s criterion, namely by taking into account competing theories. I
will call this an “historical” (as opposed to purely logical) account of corroboration.
When our background knowledge includes another potential
explanation of the fact in question, then our hypothesis can be corroborated
if it is able to “predict” some fact that cannot be explained by, or
that apparently falsifi es, its predecessor. 21 Whether that fact is known or
unknown is irrelevant.
What if the theory we wish to test has no predecessor? In particular, what
if it is the only hypothesis on offer, with regard to a particular fact? As we
have seen (4.3.2), proposed theistic explanations are often like this. When
Richard Swinburne argues that the theistic hypothesis would explain the
very existence of laws of nature, 22 he is claiming to explain a fact which—
as Elliot Sober notes—“no other hypothesis really engages as a problem.
This is an instance of inference to the ‘best’ explanation only in the Pickwickian
sense that just one explanation has been suggested.” 23 Assuming