Darwin's views of phyletic formation (wasFwd: Alvin Plantinga's paper)

Tue, 26 Jan 1999 07:00:21 EST

In a message dated 1/25/99 7:05:41 PM, Adam wrote. (I will pick out what I
consider to be the critical statements):

<<Okay, now what's going on here. Species arise, and as they diversify
they form distinct and higher taxonomic categories. What species are we
talking about here? Modern ones that form the base of our hierarchies,
or progenitor species whose descendents will became the modern day

Snip Darwin's quote.

<<That follows - but think. What's the time flow here? He's (Darwin) not
about modern descendent species diversifying into genera - he's talking
about progenitors. As life diverges forth into diversity, so we'll see
higher and higher levels appearing. If we start with the common
bilaterian ancestor that's what is seen. The Cambrian beasties might
have fit into certain phyla, but that's how we'd fit them based on their
similarity to modern forms. Personally I can see your difficulty, and
it's clearly a rather clumsy way of putting things, but fundamentally
there is no problem. Higher taxonomies aren't possible until you have a
lot of descendent species, genera, families etc... but that's the way it

Let me pick out the crucial statement from the above: You wrote, "As life
diverges forth into diversity, so we'll see higher and higher levels
appearing. If we start with the common bilaterian ancestor that's what is

Your statement is not based on empirical fact. The fossil record shows just
the opposite. The statement should read, "As life diverges forth into
diversity, so we'll see _lower and lower_ levels appearing." That's what the
fossil record shows. I will be glad to send you references of paleontological
studies that support the lower-to-lower direction of phyletic change, if you
wish them. If you have empirical evidence to support your statement, I'd like
to have it.

You are aware of the current studies called, "evolution made visible". These
studies show how natural selection in the short term produces minute changes
in species that then form new species or varieties, such as melanism in
peppered moths and change in spots in guppies coloration. Why are these
studies being conducted? In an attempt to provide an empirical base for
Darwin's hypothesis that phyletic hierarchies start from the lowest taxonomic
level and build up to higher levels. None of these studies, however, show any
series of adaptive changes that eventuate in higher taxonomic levels.

You wrote, <<As for the Cambrian explosion: phyla didn't spring forth fully
utterly distinguished by all their current forms. Generalized ancestral
forms appeared and then diversified, but in their earliest days how far
apart were they? That's a current research question that's really
obscured by the nature of the Cambrian and Pre-Cambrian remains -
scarcity and difficulty of access. We have more remains than we've ever
had, but the Cambrian is still a small proportion of fossils compared
with later times. But there's encouraging signs that relationships and
lines of descent will be resolved. Or so it seems to me.>>

The Cambrian beasties are distinguished by their body plans. The body plan
defines the basic architecture for the future phylum. The body plan for
Pikaia, the probable progenitor of Phylum Chordata, is characterized by a
notochord and striated musculature. No other Cambrian animals possess these
characteristics, but all the progeny of Pikaia do, at least sometime in their
embryonic form. As further morphological features were added to the body
plan, new lower taxonomic levels emerged, until you finally find the Linnaean
species of the phylum.
I wrote, <<It's a problem because Natural Selection in the linch pin of the
evolutionary world view. If however, NS is a non-player in the
formation phyletic lineages, the anti-Judeo-Christian bias of
evolutionary science is irrelevant.>>

You responded, <<I don't think any of that really follows from the pattern you
perceiving. The origin of phyla is a puzzle, but there's no evidence for
anything other than natural selection acting on variations as the
physical creative process.>>

My response, "There is no evidence that natural selection acted on variations
as the physical creative process. You are invoking natural selection by
default. The truth is, nobody knows how the body plans of Cambrian animals
were formed. To say that natural selection did it is simply to invoke the
standard Darwinian answer in lieu of any evidence. By doing so, however, you
forestall the search for any other mechanisms. I am simply skeptical of
natural selection as a creative process, and suggest that we all should think
creatively about other processes.

You wrote, <<A creation model that fits the current data will be superceded
as more evidence accumulates for early links between phyla. The mystery lies
in why were the variations so unlike anything else today, not how did they
then evolve.>>

I disagree. How phyletic lineages change during geologic time is fully as
important a problem as that of why were variations so unlike anything else
The history of changes in phyletic lineages as they made their journey through
the ages after the Cambrian explosion is a test case for Darwinian evolution,
and in my opinion, based on empirical studies, it comes up short.
>You wrote, "Plantinga's argument stinks because it's a sell-out to
>hyper-relativism. Christianity is about Truth, wherever it's found.
>However he does have a point about the Deicidal tendencies of
>materialist evolutionists. Evolution isn't really a conditional
>proposition, but "God is dead" is."
>I don't know how to respond to your statment.
What I meant, in my muddled way, was that atheists ["god-killers",
deicides] who see evolution as disproof of God are wrong.



Thanks for this exchange.

Best regards,