07.22Creationists Run Afowl of the Evidence
by Steven Novella, MD
I have long been fascinated by creationism, for it is the purest and most developed pseudoscience in our culture. The scientific community, after more than a century of mounting evidence and vigorous debate, remain solid in their collective conviction that life on Earth did in fact result from the process of organic evolution. There remains no serious scientific objection to this conclusion, and biological evolution has earned itself, as much as any idea in science, the designation of scientific fact.
And yet there exists individuals, institutions, and journals dedicated to the idea that evolution has not occurred on our planet, and advocate instead the older concept that life on Earth is the result of divine creation. In order to maintain this belief, adherents must exercise an increasingly sophisticated and complex system of rationalizations and mental gymnastics. They freely engage in distortion of fact and logical fallacies, in fact they invent new logical fallacies when necessary, in order to maintain their beliefs in the face of an onslaught of scientific evidence and thought. The result is a pseudoscience that is disturbing and often frustrating to encounter, but also invokes a morbid fascination. In some sense creationism may also serve a purpose, in that it presents for the scientific and skeptical community an excellent example of the many ways in which thinking can be distorted to serve a purpose other than pursuit of the truth.
The Fossil Evidence
There are three broad categories of evidence for the fact of evolution. The first is the morphology and genetics of existing species, which possess features which retain an imprint of their evolutionary past. The second is minor fluctuations in gene frequencies within populations – the baby steps which may be extrapolated to speciation and therefore permanent evolutionary change. The third independent line of evidence is the fossil record, on which this article will focus, and more specifically the fossil evidence for the evolution of birds from reptilian ancestors.
When Darwin wrote The Origin of Species, the fossil record was sparse to say the least, representing a critical lack of evidence for his new theory. Creationists contemporary to Darwin used this fact as their primary criticism of evolution, with some legitimacy. Darwin knew that the decades to come would either vindicate him with a wealth of fossil evidence, or doom his theory to failure if such evidence would not be forthcoming. Darwin, I believe, would be very pleased to witness the host of transitional fossils, documenting in various degrees of detail the evolutionary history of our planet.
These transitional fossils, while representing an ever growing mountain of evidence in support of evolution, have become a serious problem for those espousing special creation. We now have excellent fossil evidence for the evolution of reptiles to mammals, terrestrial mammals to whales, and ape ancestors to modern man, only to name a few of the most spectacular examples. One of the most significant, and arguably the most beautiful, of transitional fossils is the Berlin specimen of Archaeopteryx, an early bird with a host of reptilian features. The sight of this small reptile sporting wonderfully modern avian feathers would likely have brought Darwin to tears.
In 1860 Hermann von Meyer first described and named a newly discovered species of ancient bird, Archaeopteryx lithographica, based upon a single feather impression. Archaeopteryx means, literally, ancient wing, and lithographica honors the limestone quarry in which the specimen was found, the fine limestone being used as a medium for making lithographic plates. One year later, in 1861, Meyer discovered the fossilized remains of the creature to which the feather belonged, in the private collection of an amateur collector, Carl Haberlein. This was the first fossil of Archaeopteryx to be discovered, and was eventually named the London specimen. There are currently seven specimens of Archaeopteryx. The best specimen was the next to be discovered, in 1877 by Carl’s son, Ernst Haberlein (in reality, both specimens were found by quarrymen, but were acquired and brought to public attention by the Haberleins). What has since been known as the Berlin specimen is the most beautiful and famous of the seven fossils, and consists of a slab containing fossilized bones and feather impressions, and the counterslab, or opposite plate, with mirror image impression.
All seven specimens were found in the Solnhofen region of Bavaria, what was 150 million years ago a shallow muddy lagoon. Animals dying and falling into the lagoon were quickly buried in the fine sediments at the bottom, where they were protected from decay and destruction. Over time the animal remains were fossilized as their bones, and even soft tissue, were replaced with minerals. Today Solnhofen is a limestone quarry, which incidentally produces hundreds of excellent fossils, among them the only known fossils of Archaeopteryx.
The London and Berlin fossils were an immediate sensation, especially among evolutionary biologists, for the specimens produced both timely and stunning evidence for the new and controversial theory of evolution. Archaeopteryx has numerous reptilian features, which most closely resemble a small theropod dinosaur. These include a long bony tail, three clawed fingers on each hand, teeth, abdominal ribs, solid rather than hollow bones, and many other features. The specimen also clearly shows avian features, such as a furcula, or breast bone, a retroverted pubis, an apposable hallux (big toe), and, most significantly, wings with modern avian feathers. (Holtz, 1999) Experts now agree that Archaeopteryx could fly, but it was a very poor flyer. It also lacked certain adaptations of modern birds, such as a triossial canal, which is an anatomical feature necessary for birds to perform a “wing flip” maneuver, necessary for taking off from a standing position on the ground. Although it has a furcula, it lacks a keeled breastbone, necessary for attaching powerful flight muscles. These are just the most obvious of the many anatomical details that identify Archaeopteryx as possessing a mixture of reptilian and avian features, with some of the avian characteristics primitive in form.
It is difficult to imagine a more perfect transitional specimen. Archaeopteryx has undeniable reptilian (now considered almost certainly dinosaurian) features combined with clear avian features allowing for primitive flight. It is more bird-like than any reptile, and more reptilian than any bird. This is a smoking gun of evolutionary change if ever there were one – the quintessential transitional species.
Let the Rationalization Begin
Creationists, however, have never let the facts get in the way of a good argument, or maintaining their preferred beliefs. True to the credo of pseudoscience, they begin with their desired conclusion, and then will commit any illogic or distortion necessary in order to support that conclusion.
With regard to Archaeopteryx, they have adopted what has become a favorite strategy of theirs. If one looks at the whole picture of the fossil evidence, what one sees is new species appearing in the fossil record – suddenly by geological standards – then persisting for a few million years on average, and then just as suddenly disappearing from the fossil record forever, marking their extinction. In an even broader sense, categories of animals (higher taxonomies, in the scientific lingo) also make an appearance, persist for a time, and then disappear – except for those which have persisted to the present time. The fossil record therefore tells a story of life’s evolutionary history.
The fossil record also shows that during the lifetime of a species, most species remain relatively unchanged, and clearly do not show any directional, or evolutionary, change. Niles Eldridge and Stephen J. Gould have termed this feature of evolutionary history punctuated equilibrium. They argue that species with large populations and wide geographic distribution – those most likely to be represented in the fossil record – are stable, in equilibrium with their environment, and are therefore not actively evolving. This stability is occasionally broken by small isolated populations, often living at the edge of the range of their parent species, who evolve rapidly (5-50 thousand years) into a new species. These rapid speciation events “punctuate” the equilibrium that dominates a species’ history on Earth. This punctuated equilibrium model of the tempo of evolution has replaced the traditional Darwinian model of continuous gradual change, based upon the fossil evidence.
Creationists interpret the evidence differently. They all but ignore the generally accepted theory of punctuated equilibrium, and choose instead to focus myopically on the regions of stability within the fossil evidence. They then conclude that the fossil evidence disputes evolution because it shows no change. They ignore the “punctuation” in the equilibrium, and the fact that the fossil evidence documents the appearance of new species over geological time.
In this fashion creationists also focus, in willfully near-sighted fashion, on the gaps in the fossil record and ignore the links. They can do this because the fossil record is gappy, documenting a very small percentage of all individual organisms that have ever lived. Creationists insist that there are only gaps and no connections. They accomplish this conclusion by defining a gap any way they choose. How much of a disparity, for example, between evolutionarily related species constitutes a gap? If such a gap is filled in by new fossil evidence, this only divides one large gap into several smaller gaps. No matter how many transitional fossils are discovered, the creationists will always have smaller gaps to point to. Some creationists argue that there should be no gaps at all – that the fossil record should demonstrate, if evolution were true, a continuous alteration of species, one blending imperceptibly into another. This criticism, however, ignores the concept of punctuated equilibrium, which nicely explains why this is not so.
Along these lines creationists will typically characterize a new transitional fossil as belonging to either one or the other of the groups that the fossil is transitional between. For example, they take the spectrum of fossils representing the evolution of man from ape ancestors and call the more primitive half “apes” and the more modern half “human” and dispense with the obvious sequence through mere labeling.
Their initial strategy with Archaeopteryx was to call it a “bird.” It has feathers, they argued, therefore it is a bird. The Creation Science website, for example, declares:
“However, the evidence for this creature (Archaeopteryx) being a bird is compelling. No other creatures except birds have feathers and a wishbone. The primary feathers are like modern feathers, with an asymmetrical design.”
Duane Gish echoes this argument when he wrote:
“The so-called intermediate is no real intermediate at all because, as paleontologists acknowledge, Archaeopteryx was a true bird–it had wings, it was completely feathered, it FLEW. . . It was not a half-way bird, it WAS a bird.” (Gish, 1979)
Gish and other creationists simply chose to ignore the actual anatomy of Archaeopteryx, including all of its reptilian features. They simply dismiss the reptilian features by saying “some fossil birds have these features,” but ignore the clear evolutionary implications of reptilian features in a primitive bird. Henry Morris of the Institute for Creation Research wrote:
“Most birds don’t have teeth, but there is no reason why a Creator could not have created some birds with teeth . . . For some reason, those that were created with teeth have since become extinct.” (Morris, 1974)
So Morris argues that God could simply have created some creatures that happen to look like transitional forms and also happen to have become extinct. This is a classic non-falsifiable hypothesis. By this reasoning, Morris can explain away any aspect of the fossil record he chooses, and in fact he eliminates the possibility of any fossil discovery which could support evolution.
They also point out, as above, that the feathers of Archaeopteryx are fully modern, and are indistinguishable in form from the feathers of, say, a bluejay. Modern feathers are asymmetrical, with the primary shaft off center, creating a narrow leading edge and broad trailing edge. This form creates an effective airfoil, as is seen in all flying birds, while absent in non-flying birds. Show me, they argued, a transitional feather (an example of focussing on the smaller gaps). Ah, but did they not say to Darwin, “Show me a transitional fossil?” There is little doubt that the creationists will be able to rationalize away a transitional feather as easily as they have a transitional reptile/bird (perhaps we shall see later in this article).
More recently creationists have adopted the opposite strategy, arguing that Archaeopteryx is a dinosaur, and not a bird at all. In order to maintain this claim, they have to explain the feather impressions, and one ingenious creationists has done just that, by arguing that they are the product of a hoax. The hoax claim, by the way, has been put forward by creationists from time to time since the discovery of the London specimen in 1861. If the feathers are dispensed with, then what is left is a simple reptile, they argue. They conveniently ignore the other avian features, such as a furcula (wish bone) that creationists previously used to argue that Archaeopteryx is a bird. Apparently, creationists have no difficulty focusing on whichever half of the evidence suits them at the moment, and ignoring the other half.
The Christian Science Fact website even tries to maintain both arguments simultaneously, when they wrote, “Is Archaeopteryx a flying reptile, just another bird, or a fraud – a reptile with wings added? Take your pick; whatever way, it is definitely not a transitional species…” (7) On one page they argue for its bird characteristics, on the other for its reptilian characteristics, and seem unconcerned about this contradiction.
The modern hoax claim was initially put forward by Sir Fred Hoyle, a British astrophysicist who is an outspoken critic of evolutionary theory. Hoyle was soon joined by others in this hoax challenge: N. Chandra Wickramasinghe, also an astrophysicist, Lee Spetner and R.S. Watkins, both physicists, and John Watkins, a physician. Hoyle initially became suspicious by the historical fact that the first two Archaeopteryx specimens, the London and Berlin specimens, were discovered and sold by father and son, Carl and Ernst Haberlein. He dismissed the feather impressions on other existing Archaeopteryx specimens as the product of imagination. Upon examination of the fossils, Hoyle and colleagues felt there were several suspicious features, such as the double feather impression, and that the feather impressions look as if they are embedded in a different medium than the rest of the fossil.
The arguments that the London and Berlin specimens are a hoax have been thoroughly refuted in the technical literature. The double feather impressions, for example, have been found to be due to the fact that Archaeopteryx had two layers of feathers, similar to modern birds. Chemical analysis has shown that the feather impressions are imprinted in the same material that constitutes the rest of the fossil. Feather impressions were found underneath other fossil bones, and microscopic cracks are continuous between the feather impressions and other regions of the fossils (both features impossible in a forgery). All Hoyle and his colleagues managed to demonstrate with their accusations was their own naivete and ignorance of paleontology. A more detailed treatment is beyond the scope of this article, but I refer you to the Talk Origins Archive (Nedin, 1997).
Since these most recent accusations of fraud have been made, new specimens of Archaeopteryx have been discovered with clear feather impressions, such as the Solnhofer Aktien-Verein specimen discovered in 1992, laying to waste any attempt at maintaining that Archaeopteryx is not a genuine species. Despite this, some creationist literature still boldly maintains that Archaeopteryx is a hoax (creation science website, 1998).
Another favored strategy of creationists is to attempt to portray the concept of evolutionary change as ridiculous and unimaginable. This has been termed the argument from personal incredulity, and is a classic creationist logical fallacy. As part of this line of argument is the idea that the transitional forms would not be functional. What good, they will argue, is half a wing, or half a feather? If a primitive proto-wing cannot be used for flight, then evolutionary processes cannot select for this feature, and therefore such a complex structure simply cannot evolve.
They add emotional power to this strategy by invoking absurd images of impossible chimeras, a flimsy straw man for them to knock down. For example, with reference to the evolution of whales from terrestrial mammals, Duane Gish invoked the image of a cow taking to the waves, a survival strategy that he characterized as an “utter failure.”
Again, creationists simply chose to ignore the viable solutions to such problems that have been put forth by evolutionists, starting with Darwin himself. The key concept they ignore, or simply do not understand, is that the current utility of a structure does not always correlate to past function. Bird feathers, for example, may have initially evolved as insulation for thermoregulation. Proto-wings may have been used to guide the trajectory and increase the distance of long predatory pounces. Alternatively, they may have been used to guide and slow the descent of such pounces from perches at some height. These primitive wings could then have been appropriated, after they evolved to a suitable size and structure, for full flapping flight.
The final strategy employed by creationists to dismiss Archaeopteryx as a primitive bird is to claim that a modern bird has been discovered which dates to the same period (as an aside, they rely upon the same dating techniques for this argument that they otherwise dismiss when used to establish the ages of life on Earth). Gish writes: “A fossil of an undoubted true bird has been found in rocks of the same geological period as Archaeopteryx! . . . Obviously, Archaeopteryx cannot be the ancestor of birds if true birds existed at the same time.” (Gish, 1979)
Unfortunately for Gish and other creationists, this statement is both factually and theoretically incorrect. He is referring to the so-called “protoavis” discovered in Texas by Sankar Chatterjee (Chatterjee, 1991). Protoavis is not a modern bird, but another putative ancestor with reptilian features. The fossil, however, lacks any feather impressions, which would clinch the specimen as a primitive bird. Chatterjee has refused access to his fossil by other paleontologists to independently study this potentially interesting fossil.
The theoretical error, common among creationists, is that ancestors cannot be contemporary to descendents. This is based upon the false, and older, concept that evolution proceeds in a linear fashion, and that all creatures can be placed in a straight line of descent. Evolution, rather, is bushy, with many side branches. One side branch may persist with “primitive” features, while a neighboring branch evolves in a novel direction. There are many examples of this even among living species. The duck-billed platypus, for example, shares many “primitive” features with early mammalian ancestors. Archaepoteryx may therefore represent a side branch that separated from the branch leading to modern birds and then persisted for a time with primitive features it shared with bird ancestors. It may also be that still older fossils of Archaeopteryx are yet to be discovered. Keep in mind, this discussion is intended to point out the illogical basis of the creationist argument – no truly modern bird has been found which is contemporary to Archaeopteryx.
Which brings us to the title of this article – new fossil evidence for the evolution of birds from theropod dinosaurs. Despite its gappy imperfection, the fossil record continues to produce a steady stream of new fossils which nicely fill in existing gaps and continually expand the story of life’s history on Earth. In the 1980’s, for example, fossil finds in Pakistan filled in the sequence of evolutionary changes from terrestrial wolf-like mammals to cetaceans – whales and dolphins. This sequence includes Ambulocetus, a primitive whale with fully functional hind legs.
Archaeopteryx in and of itself is powerful evidence for an evolutionary link between dinosaurs and birds. New fossil specimens, however, coming out of fossil beds in China, have done for bird evolution what the Pakistan finds have done a decade earlier for whale evolution, multiplying by many times the weight and power of the fossil evidence for the evolution of birds. I will give only a few especially pertinent highlights here; for those interested in a more thorough overview of these recent fossil finds, see Dinosaurs Take Wing by Jennifer Ackerman, in the July 1998 National Geographic, pages 74-99.
The first new fossil to consider is Sinosauropteryx prima, discovered in 1996, which is a small meat-eating dinosaur with furry scales. The creature did not have wings, and the whispy fur was most likely an adaptation for thermoregulation. The filamentous fur may very well be proto-feathers, and many paleontologists place Sinosauropteryx as a direct ancestor of birds.
Two other recent discoveries, Protarchaeopteryx robusta and Caudipteryx zoui, are even more stunning. They both resemble Archaeopteryx, but are more primitive, with shorter wings, bigger teeth, and larger powerful hind legs, although with clear feathers on their arms and long bony tails. Despite their feathers, neither creature could fly. In line with their primitiveness is another startling feature, their feathers are symmetrical. Modern birds, and archaeopteryx, have asymmetrical feathers, as discussed above. Both of these more primitive creatures have more primitive feathers and therefore lack this adaptation for flight (Aha! The sought after transitional feather.)
On the other side of Archaeopteryx was discovered Confuciusornis sanctus, which also bears resemblance to Archaeopteryx but is more modern. Confuciusornis has lighter bones, and a shorter more bird-like tail, and has lost its teeth in favor of a more beak-like jaw. This creature was clearly a better flyer than Archaeopteryx, but still not up to modern standards.
The presentation of these creatures in an apparent sequence is not meant to suggest a direct linear evolutionary heritage. These species represent a few branches from the robust bush of species living between 230 and 150 million years ago when one branch of small theropod dinosaurs was evolving into birds. They do, however, exhibit a compelling sequence of features, filling in the gaps between such dinosaurs and modern birds. The gaps, in fact, have become so small that creationists will have to break out their magnifying glasses to see them.
1) Shipman, P. Taking Wing: Archaeopteryx and the Evolution of Bird Flight. Simon and Schuster, New York, NY. 1998
2) Creation Science website, emporium.turnpike.net/C/cs/trarch.htm, updated 9/15/95
3) Ackerman J. Dinosaurs Take Wing. National Geographic vol. 194 no. 1, July 1998; pgs 74-99
4) What Was Archaeopteryx ? Www.creationscience.com downloaded 10/30/98
5) Chatterjee S, “Cranial Anatomy and Relationship of a New Triassic Bird from Texas,” Philosophical Transactions of the Royal Society of London, B, Vol. 332, 1991, pp. 277-342.
6) Holtz T., Archaeopteryx’s Relationship With Modern Birds, www.dinosauria.com/jdp/archie/archie.htm. January 1999
7) The Case of Archaeopteryx, www.pathlights.com/ ce_encyclopedia/20hist08.htm. January 1999
8) Nedin, C. On Archaeopteryx, Astronomers, and Forgery, The Talk Origins Archive, December 1997
9) Gish, D. Evolution? The fossils say No! Creation-Life, San Diego 1979.
10) Morris, H. Scientific Creationism, 1974
The following are Letters To The Editor concerning this article
I recently read a book called “Darwin’s Black Box” by Behe. It’s thesis is that there are systems called “irreducibly complex systems” which appear to have no evolutionary advantage until all of their parts are present, and so would not seem to be candidates for evolving via natural selection through small changes. His conclusion is that these systems are evidence for intelligent design. I’d like to see an analysis of his example systems by a skeptic or hear a proposal for how such systems might have evolved.
Richard L. Ford
I read Steven Novella’s commentary regarding the creation/evolution controversy in the New England Journal of Skepticism (Winter, 1999). Very interesting stuff, and I agree that the material coming from Morris of the Institute for Creation Research is largely trash. But there are some serious voices in the scientific community that present a rather cogent argument for the position largely referred to as “Intelligent design” and these should be considered in terms of the debate. Authors include Polkinghouse, Denton, Behe, and Hugh Ross, just off the top of my head.
I really have to wonder if “Skeptics” are being true to their principles, i.e., challenge positions not supported by data, with regard to contemporary notions of evolution. For example, there is precious little evidence for the punctuated equilibrium hypotheses and virtually none for life arising from some sort of primordial soup, yet you present these ideas as virtual certainties in your article. As an unbiased observer, it seems to me the skeptic community has taken on the role of apologist for the biomedical community establishment.
Jim Mitroka, Ph.D.
Behe’s conclusions in “Darwin’s Black Box” are really nothing new, and have been part of the standard creationist objections to evolution since the time of Darwin. Behe’s line of reasoning, however, suffers from several critical logical flaws.
The first is called the Argument from Personal Incredulity, which is basically the argument that because a person cannot conceive of or imagine a solution, no solution therefore exists. Nature, however, is not limited to the imagination of Behe, or even evolutionary biologists. There are many very complex biological systems in nature, and it is not always possible to think of a compelling evolutionary sequence to explain every step in the formation of such systems. This lack of an ability to weave a convincing evolutionary tale, however, does not rule out the possibility that the complex system in question did in fact evolve.
The second fatal flaw in Behe’s line of reasoning is that a complex structure must have evolved directly for its current utility. Since it could not function in its current utility if it were any simpler, he argues, then it could not have evolved. His unspoken major premise, however, is false. Darwin himself recognized that structures may have evolved from precursors that had completely different functions. A classic example is that of bird wings. Half a wing is certainly no good for flying, and many creationists have therefore argued that it could not have been selected for. There is now stunning fossil evidence of bird ancestors with half wings, and even before this discovery it was speculated that such creatures must have existed and perhaps used their protowings for stabilization during long jumps or gliding descents, thermoregulation, catching insects, or some other purpose. There is now good evidence that insect wing precursors were used for skimming along the surface of water, before they were ever usurped for flapping flight.
Behe uses, as one of his examples, the cilia of a cell. This is a fairly safe example for him to use, since such microscopic structures do not fossilize and we will likely never be able to document the evolution of cilia. Modern cilia are certainly complex, but their precursors did not have to be. Pre-cilia likely served a different function for the cell than do modern cilia. Behe is correct in stating that no one has proposed a completely fleshed out pathway for the evolution of cilia, but this is hardly surprising, nor is it a black mark against the feasibility of evolution.
Single cells evolved over three billion years. All multicellular life evolved over the next 600 million years. Three billions years is a tremendous amount of time, and allowed for the evolution of a great deal of complexity on the cellular level. The possible evolutionary pathways that cellular proteins and structures could have taken in this time is tremendous, and it is no wonder that reconstructing these pathways stretches the human imagination. It is not reasonable to demand that this should be an obvious or simple task, lest doubt be cast upon the fact of evolution.
Behe also makes other unspoken assumptions in his reasoning – namely that structures must work well or efficiently in order to be of value to the organism. This is not true, and nature if full of examples of clumsy and imperfect structures that merely get by. Also, he assumes that while a structure is evolving through necessarily useless stages, it would be a detriment to the organism since it would not serve any useful function. Behe, however, ignores the possibility of redundancy – an important concept in evolution. If a structure is redundant, then it is free to evolve in essentially random directions (so called, genetic drift), even ones that serve no immediate purpose, while its redundant structures perform the tasks for which it originally evolved. Every step in an evolutionary sequence does not have to serve some specific purpose, or offer a concrete benefit to the organism. In this way evolution may be chaotic and messy, and almost impossible to “reverse engineer.”
There is a clear genetic basis for such redundancy. Genes are often duplicated in an organism’s DNA, even many times. Gene multiplication may easily occur through errors in DNA copying during reproduction. Sometimes, entire chromosomes may be copied. This genetic material, although it may still produce useful proteins and structures, will be redundant, and therefore free to safely evolve in novel directions while copies of itself continue to perform its original essential function. Mutations in regulatory genes may result in the creation of redundant organs or tissues, which again would be free to take on novel functions.
In short, Behe’s arguments display a fair degree of ignorance for modern evolutionary theory and rest ultimately on faulty logic. Intelligent design is not a viable scientific hypothesis and is not being taken seriously by biologists or other scientists. It is, in fact, just warmed over creationism trying to find a new face so that it may masquerade as legitimate science.
Also, Behe’s approach to the whole question of evolution is flawed in that it is far too narrow in scope. He attempts to refute the fact of evolution through a single line of argument. Such attempts at dismissing an entire field of study through a single line of evidence have a history of failing miserably. Lord Kelvin, for example, attempted to refute all the various conclusions of modern geology (of his time) in a short paper which argued for a young Earth based upon the current temperature of the Earth and the theoretical rate of the Earth’s cooling. Kelvin, however, ignored all of the independent lines of evidence from geology that spoke of a much older Earth. Kelvin was not a geologist and was not intimately aware of this large body of evidence. It turns out that Kelvin was fatally wrong in his calculations because he did not take into account the warming effect of the radioactive decay of certain materials in the Earth’s crust. Kelvin could not have known about this factor, since radioactivity had not yet been discovered.
Behe, in the style of Kelvin, is attempting to dismiss all of the findings of evolutionary biology through a single line of argument, that of a biochemist who is not an evolutionary biologist. He does not address the multiple independent lines of evidence that point to the fact that life on Earth evolved. This evidence includes a mountain of fossil evidence, including many transitionary forms, geological evidence of strata, genetic evidence showing evolutionary relationships between living species, embryological evidence, and evidence of an evolutionary past captured in some current structures of modern organisms.
In response to Mr. Mitroka’s comments regarding punctuated equilibrium, there is a great deal of evidence to support this hypothesis. I refer the reader to papers by Gould, Eldridge and others which demonstrate that fossil lineages tend to remain relatively stable over millions of years. There is also copious evidence of new species arising in the fossil record, while older ones disappear forever. Punctuated equilibrium explains all of the available evidence better than any other hypothesis which has yet been proposed.
Also, nowhere in my article do I discuss the origin of life. Evolution does not involve life origins, only the change in life over time, although this is a common misconception. It is true, however, that there is little direct evidence for the mechanism of life origins. It must be understood, however, that life origins is by necessity an historical science. We cannot make direct observations regarding the origin of life 4 billions years ago. Also, unlike multicellular organisms, the chemistry of the primordial oceans did not fossilize (at least not in any way that has yet been discovered.) We can, however, make inferences about the origin of life, and test our hypotheses for plausibility. At present we can state that there is no theoretical objection to the possibility of life arising from non-living biochemical precursors. The building blocks of life were abundant in the primordial ocean, and many aspects of early biochemistry can be reproduced in the laboratory – such as the production of copious amounts of amino acids in a test tube containing the constituents of the early Earth atmosphere and a little electricity, simulating lightening. This remains a young science, but the early results are encouraging.
Most importantly, the claims for evidence regarding life origins do not exceed logic or the evidence. Scientists investigating this area are interested in discovering what actually happened on the early Earth, and their ideas change in the face of new evidence, ideas, and experimentation. A full and open scientific debate is under way. In contrast, the ideas and beliefs of creationists are static and unchanging, dictated by faith and not by evidence.