Here's an endnote I am adding to a
chapter I am contributing to the upcoming Handbook on Humanism (edited
by AC Grayling and Andrew Copson [Wiley Blackwell publisher]). I now realize I got something wrong in
chapter 2 of my book Believing Bullshit, so might as well set the record straight publicly. Here's the endnote of the chapter I am now writing for the new book [n.b. YEC = Young Earth Creationism]:
Elsewhere I have said that because
Ken Ham’s theory makes no predictions – takes no risks – regarding the fossil
record, so it cannot be confirmed by the fossil record. See “But It Fits!” in
my Believing Bullshit (Amherst NY: Prometheus Press, 2011). I now realize I did
not get this quite right. Were we to start excavating fossils that were clearly
stamped “Made by God in 4,004 BC”, etc., that might indeed confirm – even
strongly confirm – YEC, despite the fact that YEC does not predict such a
discovery. True, such a discovery may not be probable given YEC, but, given the
discovery is nevertheless considerably more probable on YEC than otherwise, it
would still confirm YEC to a significant degree.
So here's what I should have said
in Believing Bullshit (from the new chapter):
There’s a popular myth about science
that if you can make your theory consistent with the evidence, then you have
shown that it is confirmed by that evidence - as confirmed as any other theory.
Proponents of ludicrous belief
systems often exploit this myth. It is exploited by Ken Ham. It may also
exploited by those who reinterpret their preferred scripture or prophecy in
order to make it “fit”.
Of course, achieving “fit” and
achieving confirmation are not the same thing.
As we saw earlier, a theory can be
strongly confirmed by making a risky prediction - by predicting something that
would not be particularly likely if the theory were false.
The theory of evolution and common
descent, in its fully developed form, does indeed make many such risky predictions
– predictions that turn out to be true. That means it is strongly confirmed.
Take the fossil record, for example.
The theory predicts fossils will be dug up in a very specific order. It
predicts, among other things, that, because mammals and birds are a
comparatively late evolutionary development, their fossils will never be
discovered within the earlier, pre-Devonian sedimentary layers (which contain
over half the fossil history of multicellular organisms). If the theory of
evolution were false and YEC true, on the other hand, there would be no
particular reason to expect a complete absence of mammal and bird fossils in
those earlier deposits (indeed, YECs wouldn’t be at all surprised had such
fossils shown up). Yet, among the countless thousands of fossils excavated each
year, not a single example of a pre-Devonian mammal or bird has ever been found.
That’s some coincidence if the theory of evolution is false. (Note this is just
one example of how the theory of evolution is strongly confirmed. There are
numerous others.[i])
By contrast, Ken Ham’s brand of YEC
studiously avoids making such risky predictions regarding the fossil record.
Whatever order the fossils are dug up is of no consequence to YEC. Mammals
and birds in the pre-Devonian - fine. No mammals and birds in the pre-Devonian –
no problem. For this reason, while the ordering of those fossils that have been
excavated does strongly confirm the theory of evolution, it does not strongly
confirm YEC.[ii][iii]
[i] See for example the talk Origins archive entry by Douglas Theobald, 29+
Evidences for Macro-evolution Part 1: the Unique Universal Phylogenetic Tree.
Available online at http://www.talkorigins.org/faqs/comdesc/section1.html
[ii] Elsewhere I have said that because Ham’s theory makes no predictions –
takes no risks – regarding the fossil record, so it cannot be confirmed
by the fossil record. See “But It Fits!” in my Believing Bullshit
(Amherst NY: Prometheus Press, 2011). I now realize I did not get this quite
right. Were we to start excavating fossils that were clearly stamped “Made by
God in 4,004 BC”, etc., that might indeed confirm – even strongly confirm –
YEC, despite the fact that YEC does not predict such a discovery. True,
such a discovery may not be probable given YEC, but, given the discovery is
nevertheless considerably more probable on YEC than otherwise, it would still
confirm YEC to a significant degree.
[iii] Also notice that each new
assumption Ham introduces to try to explain away the evidence against YEC has
the effect of reducing the prior probability of his overall theory. Ham
succeeds in endlessly protecting YEC against empirical refutation only by
endlessly reducing the prior probability that YEC is true.
Comments
I remember reading in Ronald Number's book "The Creationists" that the reason that Henry Morris insisted on that "statement of faith" that originally his group then the others, were required to take was because they kept losing members when they went to normal colleges/universities.
On a related note, I know of at least one guy who is not impressed at all by the 29+ Evidences for Macroevolution site. He believes that all those scientists have somehow picked "tests" that are all "safe".
Ironically...he's no xian nor a creationist. He doesn't care for either Dan nor Sye himself!
* Analogous example: a lack of transitional fossils would be disconfirmatory for the theory of evolution.
"Elsewhere I have said that because Ken Ham’s theory makes no predictions – takes no risks – regarding the fossil record, so it cannot be confirmed by the fossil record."
Either way, I agree that we should not describe Ham's theory as predicting such fossils, given that they are less than probable on his theory. In that case, the focus on predictions can be misleading: that a theory makes no predictions gives us no guidance as to whether a theory is (dis)confirmed, nor whether any evidence could (dis)confirm it. Perhaps then you should talk about a theory's generating no 'confirming or disconfirming instances', or its having 'no empirical content', rather than its lack of predictions?