On Wed, 02 Sep 1998 13:48:59 -0400, Bill Hamilton wrote:
>SZ>I never really thought about it before, and I have
>>not read Mike Behe's book (Darwin's Black Box), but when
>>Behe describes his concept of "irreducible complexity"
>>is he using "complexity" in the colloquial or the technical
>>sense? If it is the colloquial sense, this probably muddies
>>the waters more than it clears them. Can you answer this?
I will use "WH" to distingish your initials from Brian Harper's in case he
joins in this thread.
WH>I read Darwin's Black Box, and Mike's definition of irreducible
>complexity looked quite colloquial to me.
Behe uses "irreducible complexity" in the same sense of "complex" that
Darwin used it:
"Darwin knew that his theory of gradual evolution by natural selection
carried a heavy burden:
`If it could be demonstrated that any complex organ existed which could
not possibly have been formed by numerous, successive, slight
modifications, my theory would absolutely break down.' (Darwin C.,
"Origin of Species", 6th ed., 1988 reprint, p154).
It is safe to say that most of the scientific skepticism about Darwinism in
the past century has centered on this requirement. From Mivart's concern
over the incipient stages of new structures to Margulis's dismissal of
gradual evolution, critics of Darwin have suspected that his criterion of
failure had been met. But how can we be confident? What type of
biological system could not be formed by "numerous, successive, slight
modifications"?
Well, for starters, a system that is irreducibly complex. By irreducible
complexity I mean a single system composed of several well-matched,
interacting parts that contribute to the basic function, wherein the removal
of any one of the parts causes the system to effectively cease functioning.
An irreducibly complex system cannot be produced directly (that is, by
continuously improving the initial function, which continues to work by the
same mechanism) by slight, successive modifications of a precursor system,
because any precursor to an irreducibly complex system that is missing a
part is by definition nonfunctional. An irreducibly complex biological
system, if there is such a thing, would be a powerful challenge to
Darwinian evolution. Since natural selection can only choose systems that
are already working then if a biological system cannot be produced
gradually it would have to arise as an integrated unit, in one fell swoop, for
natural selection to have anything to act on."
(Behe M.J., "Darwin's Black Box: The Biochemical Challenge to
Evolution," 1996, p38)
If one quibbles about Behe's allegedly "colloquial" use of the word
"complexity" while granting Darwin the right to use the word "complex" in
his famous test of his theory, then one has rendered Darwin's theory
unfalsifiable in principle.
WH>Mike's baseline example of irreducible complexity was a mousetrap. The
>salient point of his definition was that you had to have all the components >in
place for the assembly to function. The implication was that such a
>mechanism couldn't have evolved. While Mike makes some interesting points,
>I don't think the mousetrap example serves his purpoase very well. You can
>make a good case that modern mousetraps "evolved" from the deadfalls that
>have been in use since prehistoric times. Someone saw an animal crushed
>under a fallen tree and had the bright idea that he could make such an
>"accident" happen again and use it to feed his family. He propped up a log
>and perhaps manually pulled the prop (with say a rope made from a vine)
>when his quarry walked under it. Eventually someone got the idea of baiting
>the trap -- so the hunter didn't have to watch it constantly. Over time
>someone else got the idea that the trap could be made with a base and
>become portable, and someone got the idea that you could substitute a
>spring for gravity.
This just confirms Behe's argument. Obviously a human intelligent designer
can make irreducibly complex structures. The question is whether a `blind
watchmaker' using only natural processes can do it.
WH>Now the ID advocates are going to be all over me
>because they are going to say that that's not evolution, but intelligent
>design. But that's because we know that men designed traps, learning from
>the traps their ancestors and colleagues had designed.
You are right. It is not "evolution" in the sense of *biological* evolution. It
could be called *directed* "evolution" but that is just another name for
intelligent design.
WH>In the case of
>objects in nature we can't directly observe the operation of intelligence
>on successive biological designs -- only the results. But that does not
>establish that such intelligence is not in operation.
This is using the word "intelligence" in *two* different ways:
1) It might indeed be granted that there is "intelligence" programmed into
nature by the laws of nature and the initial and boundary conditions. Such
"intelligence" could work by *Darwinian-type mechanisms*. Even Dawkins
concedes that Darwinism depends on the laws of physics "deployed in a
very special way":
"All appearances to the contrary, the only watchmaker in nature is the blind
forces of physics, ALBEIT DEPLOYED IN A VERY SPECIAL WAY. A
true watchmaker has foresight: he designs his cogs and springs, and plans
their interconnections, with a future purpose in his mind's eye. Natural
selection, the blind, unconscious, automatic process which Darwin
discovered, and which we now know is the explanation for the existence
and apparently purposeful form of all life, has no purpose in mind. It has no
mind and no mind's eye. It does not plan for the future. It has no vision, no
foresight, no sight at all. If it can be said to play the role of watchmaker in
nature, it is the blind watchmaker." (Dawkins R., "The Blind Watchmaker,"
[1986], Penguin: London, 1991, reprint, p5. My emphasis.)
2) But there is another different "intelligence" that works by
*Lamarckian*-type mechanisms* of learning from acquired experience
passed on directly to one's descendants , which are *only* found to any
significant extent in *human* (using the word broadly to include hominids)
cultures. Your "But that's because we know that men designed traps,
learning from the traps their ancestors and colleagues had designed".
The first type of "intelligence" *cannot* build irreducibly complex
structures (that was the whole point of Darwin's test). The second type of
"intelligence" *can* build irreducibly complex structures.
But the first type of "intelligence" was built into the universe 15 *billion*
years ago, and began manifesting itself biologically 3.5 *billion* years ago.
The second type of "intelligence"began to emerge only about 4 *million*
years ago with the advent of hominid culture. If there *are* irreducibly
complex structures that predate 4 million years ago (like the bacterial
flagella and the blood-clotting cascade), then Darwin's "theory would
absolutely break down."
In that case, "Darwin" would no longer make "it possible to be an
intellectually fulfilled atheist" (Dawkins R., "The Blind Watchmaker", 1991
p6) and the Theory of Intelligent Design would (or at least should) resume
the scientific status that it had before Darwin.
Steve
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3 Hawker Avenue / Oz \ senojes@hotmail.com
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Perth, West Australia v "Test everything." (1Thess 5:21)
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