Theism and Explanation - Appeared-to-Blogly

Successful Theistic Explanations 127
before the portable dark sucker can operate again. If you break open
one of these fi lled canisters, one will see that there is indeed a great
quantity of stored dark on the inside. 36
And so on. Intriguingly, this account of an outrageous proposed explanation—let’s
call it “Dark Sucker Theory” (DST) 37 —also includes facts that,
at fi rst sight, might appear to corroborate it. There are, of course, many
facts that count against it. But one of these is that DST is so radically at
variance with what we already know about the world. 38 This is already suffi
cient reason not to take it seriously.
“But DST,” you might respond, “is nothing more than an internet joke.”
And that is true. So let me illustrate the importance of background knowledge
with a well-known, real-life example. 39 When Darwin set out his theory
of biological evolution, a major diffi culty facing his theory was that we could
not directly observe the process of natural selection. So a key question was:
Do we know of any mechanism of this kind to which we can appeal, which
would give natural selection the status of a vera causa, a “true cause”? 40
Darwin found such a mechanism in artifi cial selection, the process by which
plant and animal breeders select favourable characteristics. 41 As it happens,
Darwin was disappointed to see his theory rejected by the chief exponent of
the vera causa doctrine, John Herschel. 42 But the point is that Darwin felt
it was important to point to some mechanism, with which we were already
familiar, which was analogous to the one he was positing.
To say we should prefer theories that are consistent with what we already
know is not to embrace the view that explanation consists of “reduction
to the familiar.” 43 After all, much recent scientifi c explanation has been
what we might call reduction to the unfamiliar, the principles and entities
posited by both relativity theory and quantum physics being very strange
indeed. 44 Rather, what I am advocating is the view that
other things being equal, the explanations afforded by a theory are better
explanations if the theory is familiar, that is, introduces mechanisms,
entities, or concepts that are used in established explanations. The use
of familiar models is not essential to explanation, but it helps. 45
And if we must depart from what is familiar, we are safest to do so by way
of a series of conservative steps, rather than by taking a grand leap into the
dark. For as Quine and Ullian remark, “the longer the leap . . . the more
serious an angular error in the direction.” 46
7.2.1 Theism and Background Knowledge
How would a theistic hypothesis rate, when assessed against this desideratum?
The problem here is that the theistic hypothesis posits a mechanism—
the action of a spiritual being within the material world—that is entirely
unlike any other mechanism with which we are familiar. Not only does