Theism and Explanation - Appeared-to-Blogly

116 Theism and Explanation
the insight that this is how we actually choose theories. Nor does it show
that we are acting irrationally in doing so.
Since there exists no defi nite or exhaustive list of explanatory virtues, we
are forced to choose which we shall adopt. Here is my choice. A potential
explanation of some fact can be regarded as its best explanation if it possesses
the following features. Our preferred theory will have a high degree
of testability; indeed, it will have survived independent tests. It will posit
mechanisms that are at least analogous to those with which we are already
familiar, and will form part of a previously successful research tradition.
It will also be simple, ontologically economical, and informative. There is
nothing particularly authoritative about this list. The features it names are
closely related, and it may be that with a bit of reworking the number could
be reduced to three or four. And more desiderata could perhaps be added.
The fecundity of a theory—its ability to suggest new lines of research—
would be one obvious addition. But one has to stop somewhere. I have
chosen this particular set of virtues for reasons of convenience, and because
most lists of explanatory virtues will include desiderata that include or at
least resemble those given here. If a proposed theistic explanation were to
rate poorly, when measured against these criteria, this would be a suffi cient
reason to seek a natural alternative.
7.1 TESTABILITY
My fi rst desideratum in a hypothesis worthy of our acceptance is that it
should be testable. Indeed many philosophers and scientists have regarded
testability as the distinguishing mark of the sciences (and a lack of testability
as the mark of a pseudo-science). In this sense, they regard testability as
a necessary condition of at least a scientifi c explanation. For Carl Hempel,
for instance, the “methodological unity of the sciences” consists in precisely
this: that their theories are testable.
Notwithstanding many differences in their techniques of investigation,
all branches of empirical science test and support their statements in
basically the same manner, namely, by deriving from them implications
that can be checked intersubjectively and by performing for those implications
the appropriate experimental or observational tests. 3
Of course, testability, by itself, does not take us very far. Many theories
remain testable that are now entirely discredited; indeed they were discredited
precisely because they were testable (and have failed the test). As Frank
Cioffi writes, “the propensity to melancholy of those born under Saturn” or
“the immunity to appendicitis of people ignorant of the vermiform appendix”
are both eminently testable hypotheses. 4 But they are not for that reason