I've been away in California for the Mere Creation conference and
some subsequent work with Bill Dembski and Steve Meyer; hence
my delay in answering Mike's post. I think we've pretty well
exhausted this topic, so this will be my last post.
Mike writes, about the recurrent laryngeal nerve:
>The evolutionist is one up on you Paul. This nerve does a loop and
>cries out for an explanation. A functional one cannot be given while
>the historical one below can.
I agree that (so far as I know) no one has investigated the functional
significance of the loop. But not looking for a structure's function does
not mean that the structure does not have a function.
What I deny is that the "historical" explanation is either necessary
or sufficient to explain the loop. That's why I brought up the macro-
evolutionary questions involved.
Mike wrote:
> >Biologists do have an explanation for the recurrent nerve.
> >It was originally the 4th branch of the vagus nerve in the fish. Here
> >the route is direct. The nerve followed the same route through the
> >higher vertebrates but as the neck became longer the detour came to
> >look increasingly absurd.
I responded:
> I'd be interested in this explanation if Mike could explain some
> of the macroevolutionary transitions involved (e.g., the invention,
> de novo, of the amniotic egg).
Mike replied:
>This sounds like changing the subject.
Not at all. It couldn't be more relevant. Suppose a bank was
robbed in Shanghai yesterday. This morning, I come to my
office to find Chinese detectives waiting to interrogate me as
a suspect. "We found some papers belonging to you at the
scene," they say. That may be true, I protest, but how could
I have possibly flown to Shanghai, robbed the bank, and
flown back to Chicago in the time available? When all the
relevant considerations are weighed, it's unlikely in the extreme
that I could have been the robber. There is no actual mechanism
to transport me in the time available.
The same problem applies in this case. To make "descent
from non-mammalian ancestors" the explanation of the recurrent
laryngeal nerve requires bracketing a wide array of unsolved evolutionary
problems, including (for instance) the origin of the amniotic egg,
the origin of hair, the origin of the mammalian inner ear, etc., etc.
We have no theory of macroevolution to account for these puzzles.
That's why these sort of suboptimality arguments get me so
steamed. Instead of addressing the questions which really need
to be answered -- i.e., instead of providing a testable theory of
macroevolution -- many evolutionary biologists take the shortcut
of saying, "God wouldn't have done it that way, therefore evolution."
Thus, when Mike writes, "transitory teeth [in baleen whales] were
inherited from a toothed ancestor. Do you exclude this possibility.
If so why?" I reply, of course the transitory teeth could have been
inherited, but that requires a theory of *how* they were inherited, i.e.,
some explication of the macroevolutionary steps involved. Absent
that theory it is fully reasonable to deny that the transitory appearance
of teeth in whale embryos is evidence of descent -- because God
wouldn't have done it that way.
For what it's worth, I think local suboptimality is real. I need glasses
(myopia), am balding slightly, and have been hospitalized for
cardiac arrythmias. My daughters see a speech therapist. No one will
lose any money betting I won't live to see 2096. But I think a theory
of created design can make sense of these local suboptimalities.
What I don't think anyone can make sense of, however, are counterfactual,
ideal animals (e.g., the perfect panda, the perfect route for the recurrent
laryngeal nerve) postulated as endpoints on a metric of optimality. All
such claims devolve to someone's authority or aesthetics.
Thanks for the exchance, Mike. Sorry if I got huffy.
Paul Nelson