>My hubby heard that "irreducible complexity proves evolution to be impossible". He has accepted this as 'law', I'm not so easily convinced. Could any of you help me understand this claim and what makes it possible or impossible?<
Difficulties with this claim include the definition of evolution and the detection of irreducible complexity. First, irreducible complexity, correctly recognized, would only show that certain features did not evolve and would still leave evolution as an important factor in the formation of modern kinds of organisms. Secondly, recognizing irreducible complexity is problematic.
An underlying problem is the risk of a god of the gaps mentality. When I refer to the action of natural laws, I consider them to be descriptions of God's normal means of running the universe. Natural laws alone thus does not imply that God is absent but that He did nothing unusually, e.g. miraculously.
Advocates of irreducible complexity (hereafter i.c.) claim that
examples of i.c. cannot be created through evolutionary means and that such examples exist. If true, this would imply that the feature in question resulted through miraculous or technological innovation, rather than through strictly natural processes. The popular examples of i.c. are complex biochemical systems and so would indicate that ordinary evolution through natural selection, genetic drift, etc. are inadequate explanations, if the examples are correctly identified as i.c. However, this does not provide any evidence against the role of evolution in any other instance. For example, Behe seems to think that several features of the first cell are i.c., but that the further diversification of living organisms proceeded essentially by regular evolution. Thus, many things that popular young-earth advocates reject as "evolutionary" are still supported, including common descent of humans and animals and an old earth. In fact, miraculous creation of the first cell(s) foll!
owed by ordinary evolution is what Darwin said in the 6th edition of the Origin of Species. Claiming that i.c. disproves Darwin is thus wrong. However, it could challenge the conventional scientific view that evolution provides an adequate physical explanation of the emergence of life. Thus, i.c. does not really disprove evolution but rather limits its scope.
The claim that i.c. disproves evolution may be linked to the tendency of some young-earth advocates to think that any perceived problem in conventional old-earth or evolutionary views automatically allows all of those views to be rejected in favor of a young-earth view, no mater how many problems the young-earth view may have. For example, I encountered someone who claimed that Darwin's Black Box proved that species were all separately created. Despite the billing on the cover as the biochemical challenge to evolution, in fact Behe (and even many young-earth advocates) accepts the observed origination of new species.
The second problem is with the claim that good examples of i.c. are known. I.C. can be defined as any feature with complexity too great to be produced by the unaided action of natural laws. Obviously, the existence of such a featue would demonstrate the existence of some other factor besides natural laws at the time of origin of the feature. However, proving that something could not be created by the unaided action of natural laws is highly difficult, if not impossible. Several formulas have been proposed for identifying i.c. features. However, all those that I have examined appear to be written with the intent to identify complex biomolecular systems as i.c., rather than to be carefully tested to be both accurate descriptors of acknowledged examples of human intelligent action
and to not describe things acknowledged to be naturally formed. For example, there is the claim that a complex multipart system requiring every part to function could not have evolved gradually. This criterion has two problems. First, proving that no simpler version would still be functional would require testing every related system, as a more complex systems might in turn provide the link back to simpler originals (if, as is evolutionarily highly likely, later modification streamlines an originally more complex process). Secondly, a complex multipart biochemical system, when divided into smaller pieces, usually still does something. Putting together two multipart systems, each half as complex as the final one, is not such a big evolutionary step. Likewise, the stepwise addition of additional steps into a system could proceed through relatively gradual evolution while ultimately producing a rather complex system.
Likewise, definitions that focus on the uniqueness and function of the results of a process fail to take into account the flexibility of biological systems and the uniqueness of everything. Kaolin is a complex substance, including several different kinds of atoms in a precise configuration. It has many useful functions, such as the making of china, kaopectate, and adulterated flour (before the Food and Drug Act). These features are sufficient for it to qualify for several proposed i.c. criteria, yet it is formed by the action of acidic rainwater on feldspar, a common mineral.
Dr. David Campbell
Old Seashells
University of Alabama
Biodiversity & Systematics
Dept. Biological Sciences
Box 870345
Tuscaloosa, AL 35487 USA
bivalve@mail.davidson.alumlink.com
That is Uncle Joe, taken in the masonic regalia of a Grand Exalted Periwinkle of the Mystic Order of Whelks-P.G. Wodehouse, Romance at Droitgate Spa
---------- Original Message ----------------------------------
From: "Sondra Brasile" <sbrasile@hotmail.com>
Date: Wed, 12 Jun 2002 12:23:14 -0400
>
>Dear Members,
>
>My hubby heard that "irreducible complexity proves evolution to be
>impossible". He has accepted this as 'law', I'm not so easily convinced.
>Could any of you help me understand this claim and what makes it possible or
>impossible?
>
>Thank you,
>Sondra
>
>
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