Howard and George
In response to both of your comments:
I would consider genetic homology and other molecular and morphological
homologies to be evidence for evolution as pattern. They all contribute to a
picture of phylogenetic relationships, but they do not give us and understanding
of how such relationships came to be.
In that regard, George's question about what are the alternatives? is not
empirical evidence for any particular alternative. If we don't know, then
scientific objectivity should compel us to say we don't know. It certainly
should not compel us to assert claims for a particular process because we don't
have any (naturalistic) alternative. I'm not making this as an argument for
spontaneous generation or special divine action. In other words, I think that
common ancestry is supported by the evidence for the pattern of evolution. But
I don't think that the theory of natural selection as it is defined, etc. by
biologists is adequate to account for all the process of phylogenetic
development. Whether that remains a mystery depends on what empirical evidence
we may gather for the process of evolution; it can't come from repeated
assertions that the process is a fact.
Thus, I think we need to be scientifically critical of the pronouncements
scientists make concerning the evidence to the different "meanings of
evolution".
Uko Zylstra, Ph.D.
Biology Department
Calvin College
tel: (616)957-6499
email: zylu@calvin.edu
>>> "Howard J. Van Till" <hvantill@novagate.com> 10/08/01 12:51PM >>>
Uko,
As a person who habitually encourages the use of distinctions to improve
communication, I find potential merit in the distinctions among evolution as
(1) pattern, (2) process, and (3) mechanism that you recommend.
Let me see if I have a good hold on how these distinctions would function.
1. I presume that paleontology would be the chief contributor to the idea of
evolution as (1) pattern, right?
2. Where would genetic relationships among extant and recent species fall?
Would that be counted as evidence that there was a (2) process of evolution
that occurred, even if details re (3) mechanism are not fully known?
Howard Van Till
----------
>From: "Uko Zylstra" <zylu@calvin.edu>
>To: <asa@calvin.edu>
>Subject: the definitions of evolution
>Date: Mon, Oct 8, 2001, 8:50 AM
>
It's true that there's much more positive evidence for "pattern" than
for
"process". But given the overwhelming evidence for the 1st (i.e., that there
has
been a succession of many different species), what are the alternatives to the
2d?
Spontaneous generation of thousands of fully-developed species,
including Homo sap? Direct divine creation of all those species? Arrival of
them
all from space?
I'm not trying to be funny: What really are the alternatives? Are there
others I
haven't mentioned?
& if one argues for direct divine creation - what sorts of theological
questions would have to be asked? What would the idea of God miraculously
creating
huge numbers of species in separate actions mean for our understanding of the
integrity of creation? What would it mean for our understanding of God?
(Recall
C.S. Lewis' principle of literary criticism: "One magician is better than two
magicians.")
Shalom,
George
> The recent exchange over Dick Fisher's book has again raised the question of
the
> meaning of evolution and our general lack of precise definitions.
> I have always found Keith Stewart Thomson's "Marginalia" column in the
American
> Scientists (70:529-531, 1982), to be very helpful. Thomson distinguishes
three
> meanings of evolution:
> Evolution as Pattern (e.g. fish preceded amphibians in fossil record)
> Evolution as Process (e.g., fish gave rise to amphibians in fossil record)
> Evolution as mechanism (e.g., natural selection)
>
> While there is abundant evidence for evolution as pattern, the evidence
which
> is generally cited in textbooks, etc., there is scant evidence for the
actual
> process of evolution. Furthermore, the recent discussion/debate about
> irreducible complexity and intelligent design points tot he fact that there
is
> limited evidence for the precise mechanisms that account for the actual
process
> that might explain the patterns that we observe. Until we are more
consistent
in
> what me mean by evolution and more consistent in the explanation of the
> empirical evidence as to what meaning of evolution it is evidence for, we
will
> continue to have confusion and deep differences in our discussion of
> "evolution".
>
> I, for one, recognize overwhelming evidence for "evolution as pattern" which
> indicates support for common ancestry. However, I find minimal evidence for
the
> actual process which has brought about this pattern ov common ancestry.
> Speculation in this regard does not contribute to scientific objectivity.
> Scientific objectivity should lead us to say we don't know, if we don't have
the
> empirical evidence for it.
> Shalom,
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