An Introduction to the Evolution versus Creation Debate

The evolution / creation debate hinges largely on a disagreement regarding the nature of science and scientific theories. Before getting into that, however, it will be important to address the common misconception that evolution and atheism are somehow two sides of the same coin. After that we will define the critical terms in this debate and summarize the basics of evolutionary theory.

The Relationship of Atheism to Evolutionary Theory.

In short, there isn’t one. Science generally, and evolutionary theory specifically, do not disprove the supernatural God of Judeo-Christianity. Evolution does, of course, undermine some of the important arguments that have been put forward for the existence of God, such as Paley’s famous argument from design (best know for its use of an analogy between the complexity of living things and the complexity of a watch), but it certainly doesn’t undermine all arguments for the existence of God, and it never will, for the simple reason that science doesn’t address the existence of supernatural entities one way or the other.

Evolution is no more atheistic than is medicine. Practitioners in both fields exclude supernatural interventions from their explanations of the phenomena they investigate. For example, you wouldn’t expect your doctor to say, “We don’t need to research your disease because we believe it’s the result of a curse from God, so your only treatment is repentance.” Just because medicine excludes supernatural explanations as a matter of method, it does not follow that medicine is therefore committed to atheism. Medical doctors are not being inconsistent when they both believe in God, and practice medicine under the working assumption that God has not jumped in to manipulate natural laws in order to create a disease or other medical phenomena. Similarly, evolutionary science also excludes supernatural explanations as a matter of method, but again, this is not equivalent to saying that evolutionists are committed to atheism. What medicine and evolution (and all the sciences) are saying is that direct intervention by God, or other supernatural beings, is assumed to be unnecessary in explaining the phenomena they investigate.

If such supernatural explanations were allowed into the methodology of science, important problems would never be pursued. For example, scientists might simply have said that polio was God’s punishment for original sin; as a result, research into its supposed ‘natural’ causes is not only unnecessary, it is positively blasphemous. Regardless of whether or not such a belief is actually true, we have two choices: we can either walk away and try to pass laws banning such heretical research practices, or we can continue the research as if there were no spiritual or magical causes involved — as a methodology. History has shown that this naturalistic methodology is regularly rewarded with deeper insights into the workings of nature, insights that have moved the human race out of the Dark Ages. One may well believe that God is the ultimate originator of these laws, and even that He may intervene on occasion for His own purposes; but in order to advance any field of knowledge, one must proceed under the working assumption that God has not and is not now involved in the areas under study. Under this approach if we are wrong and the phenomena being investigated is supernatural in origin, then at worst our research will turn out to be a waste of time; but if we are right, and a natural cause does exist, then our human knowledge expands — we go from believing that diseases are the result of some angry deity to understanding that they are a form of predation from microorganisms; this is turn allows us to go from cowering and chanting in the face of these threats to actually controlling them.

Clearly then, the scientific method does not commit one to the belief that God does not exist, or even that God does not intervene in supernatural ways. What the scientific method does is define a methodology that allows science to move forward in all those areas in which God does not intervene, and it is effective in this only because it does not assume in advance what those areas of are. Rather than assuming that God has an explanatory role until proven otherwise, the scientific method turns this around and assumes that God has no explanatory role, until it can be proven that He has. This shifting of the burden of proof, this single change in perspective, was essential to unlocking the door leading out of the Dark Ages.

Interestingly, this methodology itself amounts to a kind of experimental test of God’s explanatory role in nature. Rather than finding our scientific endeavors regularly frustrated because so many phenomena are caused by supernatural agents, we instead find that this, in fact, never happens. Even when phenomena cannot yet be explained, natural explanations can be identified that are at least as plausible as any supposed supernatural “explanation.” (This is why theists who regularly point scientific unknowns as “proof” of God’s existence find themselves on ever shrinking ground. Such arguments are often called God of the Gaps arguments, where “gaps” refers to the current gaps in our scientific knowledge.) Science has yet to regret its naturalistic working assumption, and this fact does amount to a powerful inductive argument that God simply does not have an explanatory role in the workings of the universe. However, this does not prove that God does not exist.

Questions of whether or not God, or other supernatural being(s), exists are simply not within the scope of science, but of philosophy. Science’s commitment is to a naturalistic methodology, not a naturalistic ontology (i.e., to a commitment that nature is all that exists). Many scientists do hold to this ontological view, but many scientists do not, and they cannot be accused of being inconsistent as a result. Belief in God in not incompatible with a commitment to science’s naturalistic methodology. Having this point explicitly made is, I think, something the many theistic and Christian evolutionary scientists well deserve.1

A Brief Description of Modern Evolutionary Theory.

Some common misconceptions of the theory of evolution are typified by such questions as “If man evolved from the apes, then why are there still apes?” Questions like this point to the importance of first ensuring that your opponent has at least a basic understanding of evolutionary theory. The theory of evolution is not, as is commonly assumed, equivalent to Darwinism. The theory of evolution is an interrelated set of now well-confirmed hypotheses including descent with modification (i.e., all life being related through common descent), along with natural selection, genetic drift, and genetics as the mechanisms behind the evolutionary process itself.

The descent with modification component of evolutionary theory asserts that all life forms can trace their lineages back to earlier classes of life forms in a branching, “nested” hierarchy (forming what looks like a bush or tree), which can ultimately be traced back to the beginning of life on earth (a point that would itself likely have been the culmination of a long period during which the distinction between living and non-living matter would have been difficult to make)2. During the long period since that time, changes in body plans have accumulated in diverse directions to make all the differences we now see between all life forms. To continue the tree analogy, you can start from the tip of any arbitrarily chosen twig and follow it back to the point where it joins another twig, the “common ancestor” of the two (or more) twigs. That now thicker twig can then be traced back to where it joins another thicker twig. This process can be repeated until you ultimately reach the thickest twig of all: the root of the bush. Applied to evolution, each twig represents a particular lineage; the points where there is a joining of those twigs into a thicker one represents the common ancestor of all the lineages that can be traced back to that point. Note that this descent with modification hypothesis can be tested independently of any ideas about how it happened, or the mechanism behind it. The mechanism introduced by Darwin was that of natural selection (along with the additional hypothesis that natural selection proceeded in a gradual, steady fashion).

To understand natural selection, we start by recognizing that individuals within any given breeding population are not identical. They differ from one another in slight and not-so-slight ways. If any of these various characteristics even slightly increases the odds that the individuals possessing them will survive long enough to reproduce, then the number of those individuals possessing those traits will tend to increase after each generation. This is so simply because more parents with that trait are having children than are parents without that trait. Over time, those traits will then become the “norm” for the population. As new traits and enhancements to existing traits continue to emerge, they will be similarly “selected for,” and then also become the norm for the group. This means improvements will accumulate. Alternatively, traits that lessen the relative odds of an individual’s reproducing will tend to be “selected against.”

What does it mean to say a trait is “beneficial”? In the context of evolutionary theory it means nothing more than saying it increases the odds that the individual possessing the trait will successfully reproduce. Whether or not a particular trait will help or hinder that depends completely on the environment of that individual, where environment includes such factors as competition within and between species, predators and disease, available niches, and of course, the current traits already common in the population.

Therefore, some physical trait—height, say—might be beneficial in one environment, but harmful in another.

If a particular interbreeding population, say, a species of small rodent, splits into two because of continental separation or a change in the course of a large river, for example, then each of the groups will be subject to different selection pressures (since they are in now different environments). Since the two groups are no longer interbreeding, traits increasing in frequency in one group cannot be passed to the other group, and visa versa. Over a long period of time the cumulative effect of this will lead first to the appearance of different varieties (e.g., “races”), then to entirely different species. Note how the natural selection hypothesis mentions nothing about the possible mechanisms behind it, such as genetics, and can be tested independently of them. In fact, genetics was unknown to Darwin and was not applied to his theory until well after his death. Regardless, Darwin was still able to muster overwhelming evidence in support of his hypothesis.

The discovery of genetics and its application to Darwin’s ideas of natural selection resulted in what is now referred to as neo-Darwinism or the Modern Synthesis. With the discovery of genetics, we can now understand the mechanism responsible both for the naturally occurring variability within populations, and for the ability of beneficial (and neutral) traits to be preserved while harmful traits are reduced. We now understand that this variability is the result, during reproduction, of both random recombination of genetic information, and random copying errors (including the phenomenon of gene duplication, which actually creates additional genetic material upon which selection can operate). In addition, genetics gives us the means to solve apparent counter-examples to the natural selection hypothesis, such as the persistence of Sickle Cell Anemia, despite the fact that this disease is clearly not beneficial to the people suffering from it.3 Our understanding of genetics has also allowed the theory of evolution to be extended to include the effects of random genetic drift.

All of these interrelated hypotheses are properly considered part of the theory of evolution. This understanding should make clear a number of debate-related points. First, attacks on Darwinism are not necessarily equivalent to attacks on common descent. Darwin had some additional hypotheses that are not central to evolutionary theory. For example, he felt that evolution proceeded in a slow, gradual manner (a view referred to as “gradualism”). A prediction of this hypothesis is that there should be no “explosions” in the fossil record, and that gaps in the fossil record should be the result only of the lack of opportunity for fossilization itself, and not a rarity of transitional forms. In light of the preceding outline it should now be clear that, however valid this criticism, it is not the same thing as a criticism of common descent nor even of the mechanism of natural selection; it is instead a criticism of the mode or tempo of the mechanism behind common descent.

The role of natural selection as the mechanism behind common descent is now well established as an important one. This was not always the case, however. Lamarckism was a serious contender both during Darwin’s time and in the early part of this century. Essentially, Lamarckism is the idea that traits acquired during one’s lifetime could be passed on (at least to a degree). For example, a Lamarckian explanation for the giraffe’s long neck would be that the effects of the parent’s constant straining to reach ever higher leaves would be passed on as a slightly longer neck, which would accumulate over the generations. This idea has long since been discredited (via the scientific method described below). While the role of natural selection in evolution is now known to be an important one, debate as to the relative importance of additional factors, such as genetic drift—the accumulation in random directions of neutral (i.e., neither harmful nor helpful) mutations—continues. Debate also continues as to the mode and tempo of evolution, which some argue is hardly a disagreement at all. In particular, “punctuated equilibrium” disputes neither common descent, nor natural selection, but emphasizes only that evolution often, but not always, proceeds in fits and starts; that is, evolution is characterized by relatively long periods of little change followed relatively short periods of rapid change. Importantly, this idea predicts a rarity and not an absence of transitional forms, and examples of transitional forms are many).

With this very brief introduction to evolutionary theory a number of important points can now be understood. First, evolution is a blind, unconscious mathematical property of any system of things that make imperfect (those very close) copies of themselves in an environment where the quality of the copy affects the copying rate; consequently, it can be rather easily simulated on a computer. This technique is now used in academia and industry, and is referred to variously as genetic algorithms (GA’s), genetic programming, and evolutionary programming. For example, in GA’s the ideal design of an airplane wing isn’t created by a designer, but is instead “evolved” through random mutation, recombination and selection. The results are often completely unanticipated by the creators of the GA. Such applications of evolutionary theory provide a powerful demonstration of the important roll of “chance” in the emergence of complexity and order.

Second, there is no target design toward which evolution is somehow striving—evolution has absolutely no foresight or goals (this is easily the single greatest popular misconception), which also means that there is no progressive drive toward increased complexity or intelligence. In fact, there are many examples of simple species evolving from more complex ones. Offspring either survive or they do not. Period. There is no evolutionary “planning,” and evolution cannot “see” beyond that one step: the differential survival of characteristics in one generation.

In fact, we would expect such a process to regularly lead to less-than-ideal design solutions, which is precisely what we find in nature, and in ourselves. This is due to the fact that since evolution has no foresight, it can’t go backwards to do a “top-down” redesign in order to optimally adapt to a new environment. For example, when the Panda bear adapted to a niche of eating bamboo, it couldn’t undo millions of years of carnivore evolution and evolve an ideal bamboo-eating body; instead, its wrist bone was adapted (you’ll sometimes see the term “exapted,” coined by Steven Jay Gould, to describe this kind of jury-rigging) to serve as the “thumb” it now needs to get at its new food source. What’s more is that the Panda’s carnivorous digestive tract is extremely inefficient in extracting nutrients from its new diet, so Pandas have to go through a whole lot of bamboo to get their required nutrition (be careful where you step). This basic evolutionary concept immediately puts to rest the common creationism critique that partially evolved characteristics have no use. You might hear, for example, “What good is half a wing to an animal that is waiting for a full wing?” The answer, of course, is that before it was flight worthy, and with no “idea” that it would ever be used for flight, the pre-wing structure was either used for something else entirely, or was a genetic side effect of an unrelated feature that was being used (and therefore being selected for). For example, just as the Panda’s thumb was originally a fully functional wrist bone, early feathers may well have been a functional insulation device. This creationist critique reflects only a serious misunderstanding of basic evolutionary theory: no evolutionist ever thought that at some point in history half of a modern wing was once sticking uselessly out of some poor animal’s body. Indeed, evidence of such a process would undermine, and not support, evolutionary theory.

Now, as for why there are still apes if we evolved from apes, the answer is simply that we did not evolve from today’s apes (keep in mind the tree/bush analogy), but with them share a common ancestor that was different from either humans or apes. Generally, the more similar the species the more recent is their common ancestor; the less similar, the further back is their common ancestor.

Good vs. Not-so-good Science

Before getting into questions of evidence it is extremely important to first review the nature of scientific theories and methodology. First, let’s define some terms that often lead to confusion. “Hypothesis” can be thought of as an educated guess which has yet to be confirmed through testing. An example would be what you do when the light in your room suddenly goes off. You might hypothesize as follows: “I suspect that a fuse blew, since the electric clock went off too.” Now, this hypothesis is still subject to testing. You may test it by seeing if the whole house is without power, or by seeing if your street lights are on. In the process you’re throwing out falsified hypotheses and forming and testing new ones. Once the various predictions of your hypothesis become consistently confirmed, you have what might now be a “confirmed-hypothesis.” An interrelated set of such confirmed hypotheses, models, and directly observed facts can form a “Theory,” when collectively they provide a systematically organized body of information that can be used to effectively explain and predict real world happenings. The Theory of the Atom is a clear example, as is the Theory of Evolution.

In everyday usage, “theory” is often used interchangeably with “unconfirmed hypothesis,” or even “wild guess.” It is in this everyday sense of the word that creationists will often complain that evolution is just “a theory.” But scientists also refer to the Theory of Electromagnetism, Gravitation Theory, and the Germ Theory of Disease. When they use the term “theory, it is in the “web of interrelated confirmed hypotheses” sense of the word. In the creationists’ usage of the word, it would be just as legitimate to say the “Theory of Alien Telepathy” as it is to say the “Theory of the Atom,” but of course, Alien Telepathy is not a theory at all in the sense in which scientists use the term.

Are theories ever absolutely certain? No. But theories are not equally uncertain. For example, one could claim that while germs cause disease under the microscope, no one has ever observed germs making people sick in the human body, and no one has actually seen the electrons orbiting the nucleus of an atom . (This is similar to the creationist complaint that no one can go back millions of years and observe evolution occurring.) Science is not simply about reporting what we directly observe. In fact, the whole point and value of science is to use what we can see to tell us about what we cannot see.

If theories and their hypotheses are never technically certain, how do we know that the Theory of the Atom is any stronger than the Theory of Alien Telepathy? Basically, a theory is strong if it does not contradict itself, and if it makes testable (typically unexpected) predictions that could easily falsify the theory—but, in fact, do not. Importantly, a good theory deals with its serious counterexamples (apparent evidence against the theory) through independently testable “excuses”; that is, the excuses it makes for the counterexamples can be shown to be valid without relying on the theory itself. An example would be how Newton’s failure to explain the orbit of Uranus led not to the rejection of Newton’s theory but to the independently testable “excuse” that there was an as yet undiscovered planet, Neptune, the existence of which was independently verifiable with a telescope. Instead of being a problem for Newton, The Neptune solution provided powerful independent confirmation of his theory.4 A good theory should also show that what had looked like unrelated phenomena are actually related, and it should cause us to ask new questions that we never would have thought to ask without the theory’s insights—questions that lead to even more confirmed predictions. The strongest theories spawn new productive disciplines that further confirm the theory that gave rise to them, while spawning new well confirmed theories of their own.

The importance of independent confirmation cannot be overstated. Independently confirmed predictions create a mutually reinforced “web” of confirmations that cannot be dismissed simply by casting doubt on any one confirming test. For example, when the prosecution in a courtroom presents not just one witness, but a parade of witnesses none of whom even know each other, each corroborating the same event from different, independent vantage points, they create a very powerful case. What makes it powerful is not just that the defense has to create reasonable doubt in more than one witness’ testimony. The burden on the defense is much bigger than this, much bigger than merely showing that each witness might be wrong. It is even bigger than showing that they are all wrong. The problem is making it reasonable to suppose that they all independently came up not just with a wrong answer, but with the same wrong answer—independently of each other. The odds of such event would be astronomically small.

Now even when all these criteria are met by the best scientific theories in history, those theories are never absolutely certain. In fact, it is possible, though perhaps extremely unlikely, that such a theory will be completely overturned. Far more likely, however, is that a theory with such a success record will be enhanced, built upon, perhaps even being shown to be a special case of a more general theory (just as Newton’s theories were when Einstein came along), but not thrown out. In fact, the history of science is just such a history: not a parade of theories that get overturned only to be replaced by the next generation of equally doomed theories, but a story of good theories being built upon, a story of real progress, a kind of “nested hierarchy” of its own—even despite frequent and ferocious resistance from various religious quarters.

In short, good theories work; they add real value and real insight, all of which produce real results. Given this understanding of what makes a theory good a special problem for any challenger theory should now be apparent. With the earlier courtroom example in mind, if a challenger points out that the dominant theory is unable to answer some question (which is typical of even the most successful theories), or that there is some currently unexplained counterexample, the challenger should not expect more than a ” yea, so?” unless she can show—and this is important—how her new theory not only fills in these gaps in verifiable ways, but how it can, in addition, better explain the vast body of successful predictions, independent corroboration, and explanatory power of the dominant theory. And beyond that the challenger theory has to make clear how all the mutually reinforcing independent confirmations of the dominant theory were coincidental errors on an apparently vast scale.

It is with this understanding of the nature of science, scientific theories, and evolution in particular, that we need to evaluate the arguments and the evidence for creationism and evolutionary theory.


1 The preceding subsection draws much from Robert Pennock’s very easily understood and thorough untangling of this methodology / ontology confusion, which is shared by those on both sides of the debate. Pennock also makes the important point that much of the fear that appears to motivate creationists comes from this confusion, as well as from an unfounded view that morality can be meaningful only if it comes from a supernatural being. See Robert T. Pennock’s, Tower of Babel: The Evidence Against the New Creationism (Cambridge: The MIT Press, 1999).

2 In a personal correspondence, Vincent M. Wales provided some helpful suggestions on a earlier draft of this article, including that of emphasizing the fact that evolution does not specifically require a single, common ancestor. Building on Wales’ suggestion, I would also hasten to add that the theory of evolution does not specifically address the origin of life at all, only its subsequent development. However, this is not to say that its principles are not a key part of the work being done in origin of life research, nor to say that the evidence supporting evolution is not highly suggestive of there having been just one common ancestor.

3 Genetics provides the insight by showing that the disease results from the presence of a recessive gene, and that a recessive “carrier” of the Sickle Cell gene is at an advantage in environments where malaria is present. “Recessive” in this case means that if you got the gene from only one of your parents, you will not exhibit the Sickle Cell symptoms, but you will be highly resistant to malaria; however, if you got the gene from both parents, you will suffer the full effects of the disease. With this insight, the puzzle is solved because the beneficial effects of the Sickle Cell gene in recessive carriers is selected for. Of course, this applies only when the population is being exposed to malaria. This neo-Darwinian model explains not only the disease’s persistence, but its persistence only in populations that are exposed to malaria.

4 I take this example, as well as much of these methodology of science concepts from Philip Kitcher’s, Abusing Science: The Case Against Creationism (Cambridge: The MIT Press, 1993).

Evolution: Converging Lines of Evidence

The strength of any theory comes not from a single measurement or a single confirmed prediction, but from the theory’s many predictions being confirmed by many independent tests, samples, and methods.  Often, attacks on evolutionary theory take the form of showing that some measurement technique is not infallible, or that some measurement technique depends on assumptions that could be wrong.  Examples, of course, include creationist criticisms of radiometric dating, which is a common technique for dating rocks.

When the creationist adds to these types of criticisms the charge that there are some things evolutionary theory cannot explain, it can seem to some that evolutionary theory is a weak, speculative hypothesis.  But as we will show below, scientific theories aren’t strong because the measurement techniques that confirm them are perfect, or because they have no open questions.  If this were the case, all science would be weak and speculative.

The best way to illustrate the fundamental problem with the creationist critique is by way of an analogy.  Let’s say I’m the prosecuting attorney in a felony case, and my case depends on placing the suspect in a certain location between 4:55 PM and 5:05 PM, during which the suspect shot someone.  Now let’s say twenty of my witnesses happened to look at their watches (a combination of analog and digital watches) when they saw the suspect shoot.  Seventeen other witnesses separately recall seeing the suspect shoot just as the 5 O’clock news was coming on in each of their apartments in the neighboring building.  Twenty six other witnesses saw the suspect shoot just as the  5 O’clock whistle blew at the nearby quarry.

Now, imagine the defense carefully pointing out that watches have been known to be wrong.  Watches, he stresses to the jury, are not infallible.   He proudly brings in people to testify that they have made mistakes at some point in their lives about the time of day because their watch’s battery had run down, or their watch had gotten wet, or damaged by various means.  As for the 5 O’clock news, the defense points out that scheduling errors in TV programming have been known to cause shows to come on more than five minutes after or five minutes before their scheduled time, and he even finds a TV producer to testify about a time that this did, in fact, happen.  And as for the quarry, the defense was able to find several expert witnesses (people who blow whistles at quarries) to testify that there had been times when they blew the whistle at more than five minutes before or after the scheduled time, at each of their respective quarries.

As is obvious in this example, it is not enough for the defense to show that the methods used by each of the prosecution’s witnesses are fallible ways of telling the time.  Not only is it extremely unlikely that something was wrong with everyone’s measurement of the same event, but even if everyone were in error, we would hardly expect them to be in agreement with each other—especially when the measurements involve unrelated technologies and methods.  Creationist criticisms of the evidence that support evolutionary theory or modern geology (e.g., dating rock samples) are often analogous to this defense attorney’s criticism of the evidence supporting the prosecution’s case.  To take the defense’s (and creationists’) criticisms seriously would literally mean that we could not tell time at all simply because watches are individually imperfect.  But in science that fallibility has been specifically taken into account through the use of multiple samples and multiple independent measurement methods.  Just like our imaginary prosecutor, scientists look for independent corroboration before they consider a theory to be well supported.

In the case of rock dating, and in all significant aspects of evolutionary theory, we have just this type of wide agreement spanning many different methods and many different samples (far more samples and methods, in fact, than described in the courtroom analogy).  This first article will focus on just five of the many independent, corroborating lines of evidence that confirm evolutionary theory, with a focus on one of its key hypotheses: Descent with Modification.  The definition of this hypothesis (taken from the subject refresher article on Evolution in Freethought Debater) follows:

The descent with modification component of evolutionary theory is that all life forms can trace their lineages back to earlier classes of life forms in a branching, “nested” hierarchy (forming what looks like a bush or tree, as in the “Tree of Life”), which can ultimately be traced back to the beginning of life on earth…During the long period since that time, changes in body plans have accumulated in diverse directions to make all the differences we now see between all life forms.  To continue the tree analogy, you can start from the tip of any arbitrarily chosen twig and follow it back to the point where it joins another twig, the point of origin of the two (or more) twigs. That now thicker twig or branch can then be traced back to where it joins another branch.  This process can be repeated until you ultimately reach the trunk.  Applied to evolution, each twig and branch represents a particular lineage; the points where there is a joining of those twigs and branches represents the common ancestor of all the lineages that can be traced back to that point.

The importance of recognizing the cross checking nature of science cannot be overstated.  When one forgets that this is the basis of good theory, one can quickly lose sight of the “forest for the trees,” and literally end up haggling over irrelevant individual cases in which a result was unexpected or inconsistent with the theory.  However, some exceptions are, in fact, expected so long as they can be shown to be “outlier” results (random or statistically rare errors) that do not significantly affect the conclusion drawn from all of the data taken as a whole.  This is exactly why statistics plays such a large role in analyzing scientific data, and why scientific results are usually stated along with a statistical level of certainty.

It is perhaps understandable why creationists make these sort of irrelevant criticisms of outlier results.  Unlike actual science, creationism does “not seek organizational relationships or look for relationships in terms of universal physical laws.”1  Instead, by definition, they exist to defend a point of view—a view rooted in absolute certainty in an unchanging Truth (with a capital T).

The lines of evidence we will briefly look at are the fossil record in the geologic column; the classification of living forms based on comparative anatomy; biochemistry; embryology; and finally, biogeography.  As you review the evidence notice how the independently corroborating nature of the different lines of evidence precludes any appeal to “there was this one fossil they couldn’t explain” or “someone once made a mistake in classifying an animal,” or even, “there was once this hoax. . .”  As in the court case example, the proof is in the wide statistical agreement of many measurements spanning all of these methods, not in any single data point.

Fossil Record

The geologic column, which is the identification and classification of the different rock layers (strata), was essentially completed by 1815, almost 50 years before Darwin’s theory.  Importantly, this work was done by the creationists of the time.  They noticed that each rock strata contained a distinct collection of animals and plants.  So unique and consistent were these fossil collections in each of the layers, that certain fossils in them could then be matched to fossils in other continents to locate that layer within the geologic column (index fossils).  It is important to notice that this all predates Darwin and is completely independent of any assumptions about evolution.  Inexplicably, a common creationist complaint is that the geologic column presupposes the truth of evolution, which in turn presupposes the truth of the geologic column, resulting in a circular argument for evolution.  But as this very short history should already make clear, the geologic column makes no assumptions about evolution since it was established by before there even was a theory of evolution.

By comparing the fossil contents from the lower layers (or strata) to the higher ones, these pre-Darwin creationists (such as Cuvier, the father of paleontology and a deeply religious creationist) could see a pattern in which an individual life form would appear in one layer and then be replaced in the next layer up by multiple variations on that original, single form.  These layers were often themselves followed by layers in which all or most of those variations (and variations of variations) suddenly and completely disappeared.  These creationists also noticed that the deeper the fossil, the less recognizable it was.  As one moved higher, the forms became increasingly recognizable.  As these scientists examined more and more strata, this cycle of emergence followed by branching variations continued.

Again, this pattern was recognized before Darwin’s theory, though the pattern was assumed not to reflect any kind of relationship through descent.   Based on their observations, these creationists (and basically all geologists were creationists at this time) concluded that God must have inflicted not one, but a series of cataclysms, each followed by a new creation.  However, as they collected ever more data, they realized that there had to have been ever more of these cataclysm and creation events.

To recap, at this point in pre-Darwinian history the geologic column had been established with the lower layers understood to be older than the higher layers.  The actual ages of the layers remained unknown, however, but were assumed to be consistent with a literal reading of the Bible.  Also, at this point in history, it was apparent that a slice through the earth—like cutting through a layer cake to reveal the layers—revealed not a hodgepodge mix of living and extinct forms (as one might expect from a world-wide deluge), but an extremely ordered and consistent pattern of fossils throughout the world.  That ordered and consistent pattern was that a form would appear in one layer, and in higher layers that same form would be replaced by similar though different forms, which became progressively more different in even higher strata.  This typically ended in the wide-spread disappearance of many of the forms, and then this cycle of appearance followed by a kind of “radiation” would start over.  One thing that was also apparent even then was that the higher the layer in which a fossil was found, the more recognizable the fossil usually was, while at lower layers the forms were less recognizable, and harder to tell apart and categorize.  For example, it is easy to tell mammals from reptiles today, but if one goes deep enough, mammals and reptiles become essentially indistinguishable (e.g.,  you find groups like the Therapsids, which were one of the mammal-like reptiles that blended features of both groups).  Creationists, like Cuvier, argued that the data could be explained by a series of divine cataclysms and creations, the last of which was the Biblical Flood.

Classification of Living Forms

Setting aside fossils altogether for a moment, but keeping the observed pattern we saw in mind, let us separately look at what happens when we classify today’s living forms based on their physical forms and structures (called “morphology”).  A fair question to ask before classifying living things is, “What characteristics should we use: size, weight, what?”  Well, the pre-Darwinian, Linnaeus, who came up with the animal naming system we still use today, grouped animals by overall large-scale anatomical similarity, though this left some room for arbitrary decisions about what should be considered “similar.”  Later, the anti-Darwinian, Richard Owen, argued that if a feature could be shown to be the same structure modified for different purposes—as revealed by comparative anatomy and embryological development–then the animals should be classified closer together.  The more such structures were shared, the closer would be the classification.  He called such structures “homologous,” while structures that looked superficially the same, but were based on completely different structures and embryological development, he called “analogous.”

This homology / analogy distinction works very well because by using it one can predict other things that the animals would also have in common.  This approach allows one to gain new insights.  If you had classified by size alone, say, you wouldn’t gain any additional insights, and would know little more than the just size of the animal.   It’s interesting to ask why this approach makes for such effective predictions.  For Owen, and the creationist establishment of the time, the answer was that homologous structures revealed part of God’s plan:  He used relatively few basic templates that He modified to create all the species.  Different species that shared homologous structures were based on the same template, but each had customized modifications to meet the functional needs of the individual “kinds.”

Owen’s approach, however, also produces observations that conflict with expectations based on God’s having created each kind directly.  If each kind were separately created, then there would be no restriction preventing God from mixing and matching useful structures.  If God designed a structure to serve a purpose, then all species could benefit from that originally perfect design.  There would be no constraint on God that says once He designs a useful structure, He can only give it to other species that happen to share with that first species a set of completely unrelated characteristics.  For example, there would not be a rule that says God can only give three middle ear bones to species that have milk-producing (mammary) glands.

An all-powerful Designer should have at least as much flexibility as human designers.  Things designed and manufactured by humans show no such restrictions.  Design ideas are shared across widely different “kinds” of human creations.  This is quickly apparent when you try to create a classification of modern computers or aircraft based on their shared components.  For example, Global Positioning Satellite (GPS) technology can now be found on helicopters, biplane crop dusters, high performance fighter aircraft, and even rental cars and fishing boats.  If you had earlier created a hierarchical classification that had winged aircraft as the basis for one branch and wingless (e.g., helicopter) aircraft as the basis for another, you would now have to add GPS to both branches.  In other words, GPS technology would not be nested within just one branch, but would cut across the branches.  As a result, one cannot create a stable, hierarchical classification for human-created things in which sets of characteristics are nested one within the other.

On the other hand, if each species is related through common descent, and not individually created, then we would expect that a classification of them based on shared structures would reveal just such a nested hierarchy of structures.  We would expect this since the structural inheritance of each branch is different and any new structures have to be built from the materials at hand; that is, they have to derive from these inherited “components.”  As a result, any new structures would be confined to the one lineage in which it first appeared, and to its descendent branches.  Consequently, we wouldn’t expect to see structures cutting across the branches, as we did in the GPS example.

When we classify living life forms we see the nested hierarchy predicted by Descent with Modification.  For example, consider the following classification (cladogram)2 of a few representative, but disparate forms:

Note the pattern in the sharing of characteristics.  They are not mixed and matched, but are “nested” one within the other.  For example, within the whole group all forms share a chambered heart; nested within those having a chambered heart is a group that additionally has a vertebral column; within the group that has both a chambered heart and vertebral column are nested those that additionally have mammary glands (i.e., you only get mammary glands if you have a chambered heart and vertebral column).  The characteristics appearing at a branch point are confined to all the branches above it; they never cut across to other branches.  This nested pattern is very characteristic of all life on earth.

Descent with Modification also makes some additional, more specific predictions about the morphology of living forms.  First, since species can only work within their structural inheritance to solve adaptive problems, we would expect that as descendent species in one lineage branch out into different niches (some that involve flying and others swimming, for example), that their adaptations will involve different modifications of the same underlying structures.  These are the homologies we discussed earlier, and they are a specific prediction of the Descent with Modification hypothesis.  A corollary prediction of this view is that we would never actually find the “winged horse” seen in mythology, since that would involve entirely new appendages appearing “out of thin air,” as it were, rather than coming from existing structures.  This is why, for example, flying birds and mammals had to modify two of their four inherited appendages to get wings; that is, they had to modify their “arms” to make wings.

Second, where species from different lineages find themselves filling the same environmental niche (for example, living in different parts of the world and filling the bamboo-eating niche) we would expect to see cases of different structures being used for similar functions (as opposed to similar structures being used for different functions in the homology example); that is, we would expect to see different lineages solve the same adaptive problems with different structures—structures which reflect each lineage’s unique inheritance.  Such cases are examples of “analogies,” (or “convergent evolution” as it’s often called today) and are also predicted by Descent with Modification.  But a further interesting prediction of this theory is that some analogous structures will be inferior to others in fulfilling similar functions.  This is expected under this theory, since the inherited components of some lineages will make better designs easier to “get to” than the components inherited in other lineages.

In the case of homologies, we see exactly what is predicted.  For example, the forelimbs of all mammals are composed of the same bones arranged in similar ways.  It’s only the proportions of these bones that differ.  For example, compare the bones of bat, human, and dolphin.  While each fills a very different niche, and uses these bones for very different functions, they all have the scapula, humerus (upper arm), radius (forearm bone 1), ulna (forearm bone 2), carpals (wrist), metacarpals (hand), and phalanges (fingers).  Again, only their proportions differ.  Creationists often say that there are similar structures for similar functions, but if that’s true, then why does the bat’s wing have far more structural similarity with the human hand than it does with a bird’s wing?

In the case of analogies we see again exactly what is predicted.  For example, the shark (a fish), Ichthyosaur (an extinct swimming reptile), penguin (a bird), and dolphin (a mammal) all have forelimbs adapted for swimming.  Outwardly, these forelimbs look very, very similar; however, the internal structures are radically different: the dolphin’s fin has more in common with the bat’s wing and the human hand (including the same five finger bones) than it does with the Shark’s purely cartilaginous fin (no bones at all).  This makes sense in the evolutionary context given that the genetic inheritance in the fish lineage didn’t have bone to work with when the sharks first appeared.  So, again, the Creationist claim of “similar structures for similar functions” is falsified.  What we typically see is different structures for similar functions and similar structures for different functions.

The Australian marsupials are a particularly startling example of this kind of convergent evolution (different structures adapted to solve the same functional needs).  There are marsupial versions of mice, flying squirrels, moles, ground hogs, rabbits and wolves, just to name a few.  As different as they are from each other, they still have more in common with each other than to any placental mammal.  For example, the marsupial mouse has more in common with the marsupial wolf than it does with the placental mouse with which we are all familiar.  (This Australian example is discussed in more detail below.)

Owen’s supernatural “cost-control” explanation for these patterns is an ad hoc theory tacked on after the fact to explain data that contradicts the predictions of a theory based on an all-powerful Designer creating each “kind” separately.  Worse, his explanation requires one to contradict God’s omnipotence and omniscience.  People such as Owen apparently felt that God used relatively few templates for reasons of efficiency in the design process, in the same way that GM, for example, would not want to design each car from scratch due its being an inefficient use of limited and expensive resources.  Of course, it is entirely unclear how one is to reconcile this explanation with the notion of an all-powerful, all-knowing, and perfect Creator, who presumably isn’t operating under such resource constraints.  Unless there was a second act of creation after the “Fall” (one in which inferior designs were introduced) then one can only conclude that many “kinds” were rendered imperfect from the very beginning (i.e., before the Fall), since many of the analogous structures we see in the different “kinds” are not equally effective in serving similar functions.

An all-powerful and perfect creator who created each kind directly would be expected to have originally used the optimal design when the same function was needed.  If any inefficient functionality that we see today was due to “degeneration” following the “Fall,” then this would appear as resulting from defects appearing in a common structure, not from the use entirely different structures, which would reflect a choice that that had been made from the very beginning.

Relationship to Fossil Record and Descent with Modification

Now, let’s go back to the fossil record.  If the nested hierarchy we see in living forms reveals the particular design approach of a Creator who made all “kinds” at the same time, then there should be no connection between the characteristics of life forms (like having 3 ear bones) and the depth of the rock layers in which these characteristics first appear.  In other words, if all species were created at the same time, then there should be no correlation between elapsed time and the appearance of characteristics that define each species.

On the other hand, if all life is related through the process of descent with modification, then there should be a very specific correlation between time and characteristics; which is to say, there should be a correlation between the depth of rock strata, and the first appearance of structural characteristics in the fossils of those layers.  How should they correlate? Remember that a structural characteristic that is shared by more branches, such as jaws or a vertebral column, should first appear in layers that are deeper than those containing the first appearance of any nested characteristic.  For example, the earliest appearance of animals possessing 3-ear bones (ossicles) should appear higher in the rock layers (i.e., in younger rock formations) , than the earliest appearance of animals with vertebral columns.

This pattern is exactly what is found in the fossil record.  Referring back to our earlier tree with the lamprey, perch, lizard, mouse, and cat (which was made independently of fossils) what we find in the fossil record is that the jawless fishes (agnaths) first appeared in the deepest layers, followed in higher layers by the first appearance of bony fishes, followed in yet higher layers by the first appearance of reptiles, which in still higher layers were followed by the first appearance of mammals.  The theory of Descent with Modification not only predicts this, but is alone in being able to explain it in a productive way (that is, based on a theory with testable predictions and not by invoking Divine, mystical, or magical causes and purposes, which can be made to fit any data—which, of course, means it can explain no data).

Note that I said “first” appearance.  Obviously jawless fishes are still with us, as are the reptiles, and even the much earlier forms of life like blue-green algae.  Too often one hears comments like, “…but if we evolved from them, then why are they still here.”  It should be clear from the discussion so far that such a view represents a serious misunderstanding of descent with modification and evolution.  A parent species does not have to go extinct before a child species can emerge.  To take just one simple example, a child species can emerge when the parent species is split into two by the disappearance of, say, a land bridge, creating two islands where there had been just one.  The two groups might now diverge into two species, though one of the species may show almost no change from the original population, while the other shows dramatic change.  This could be the result of very different environmental pressures on each of the two groups.

To recap so far, we see that a tree of life made from comparative anatomy of living forms, which has nothing to do with timing or fossils, independently correlates to a tree of life based only on the appearance of characteristics as you go from deeper to shallower rock strata.

Biochemistry

Now if Descent with Modification is the right explanation of the these two independent phenomena, (i.e., the pattern in fossil record and the pattern in living organisms) then any newly discovered features should continue to corroborate these same patterns, while perhaps adding even more detail and filling in open questions.

Since Darwin’s time, the life and geological sciences have exploded, complete with the emergence of whole new sciences that Darwin could never have imagined, such as molecular genetics, plate tectonics, and geochronology (rock dating). Any good falsifiable theory should not only hold up under the scrutiny of these new sciences, but thrive and contribute to this progress of knowledge.  Looking at the new field of molecular genetics, what happens if we try to make yet another “tree of life” diagram, but based only on DNA, independent of anatomy and independent of the fossil record?  If we end up with a tree of life that is completely different from the diagrams we got based on fossils and comparative anatomy,  then Descent with Modification will have a big problem.

DNA

Briefly, DNA is a molecule on which is strung a code made up of just a four-letter alphabet.  For example, part of the whole string might read, “…GCCTTACGGA…,” where the whole string is actually about 3 billion letters long in human DNA.  When that code is read across the entire DNA, one ends up with a recipe for a growing a life form.  This four-letter alphabet really represents the four chemical “bases,” each of whose initials are A, T,G, and C (adenine, thymine, guanine, and cytosine).

Until the DNA copies itself (a process called “replication”), this string of letters exists as one side of a two-sided zipper-like structure called a double helix.  The other side of the zipper is the mirror image of the left, where T is the mirror of A, and C is the mirror of G.  When a cell divides, this zipper unzips into two halves.  Each half then builds a new sister half, letter by letter:  Ts attract As, As attract Ts, etc.  When all is done and said, we end up with two complete “zippers,” each identical to the original single zipper before it split.

Now, each group of three letters makes a “word,” (e.g., CCA is a word, or UCU, etc.).  These three-letter words are called “codons” and come in two basic types: instructions for building things, or exons; and regulatory instructions, or introns, which can sometimes be thought of as punctuation marks or “stop reading,” “start reading” instructions.  In the case of exons, each three-letter word corresponds to a particular building block of a protein molecule.  These building blocks are called amino acids. A protein is essentially a string of amino acids in a particular sequence all hooked up end-to-end.  Proteins in living things are made up of very long sequences of just 20 different types of amino acids.  The DNA code for making the whole protein is an example of a “gene,” each of which can be thousands of letters long.

A genetic mutation amounts to A, U, G, or C (actually the U stands for urasil, which is used instead of T in RNA, where RNA is an intermediate step before the protein-building process) being accidentally “flipped” to something else, or having a one or more letters deleted, added, reversed, or put somewhere else in the sequence.  For example, if the word UCA becomes UCG, then there is no effect since they both code for the same amino acid: serine.  However, if the first position is flipped, turning UCA into GCA, then the amino acid in this part of the completed protein will be alanine instead of serine.  This change to the protein may or may not affect the way it functions or the final “fitness” of the completely grown life form.

Some mutations may prevent the protein from even forming at all, such as a mutation affecting one of the “punctuation marks.”  If this happens, the entire gene of some thousands of those letters (A,C, T, U) are rendered useless, or “dead.”  (Of course, from the standpoint of affecting offspring, and therefore evolution, the only mutations that matter are those that affect the DNA copies that go into the sex cells, since only they are going to be used to grow another organism.)

In the interest of space, I’ve tried to limit this introduction to genetics to only those points bearing directly upon our discussion.  Hopefully I’ve described enough of it to make the significance of the next point clear: only around 5% of DNA actually codes for building anything, the rest are the introns along with a vast amount of dead or “pseudo” genes.  This means that most random mutations will have no impact because they will land in this vast sea of ignored dead genes.  (All introns, including these dead genes, are actually cut out to leave only the exons just before the instructions are read prior to building proteins.)

Keeping in mind that some 95% of the genetic code is nonfunctional, and also keeping in mind that random mutations appear on a fairly regular basis, we can expect that mutations affecting these dead areas of the DNA will tend to spread throughout the breeding population.  The reason they will tend to spread is that specific mutations are very rare, and they have no effect on survivability (since the dead genes don’t do anything).  Consequently, as the creature possessing this mutation reproduces, it will likely pass it on and it will multiply over the generations.  If one could find very old DNA of a particular species, and compare it to new DNA from that same species, one would expect the newer DNA to show an accumulation of these types of mutations.  Even more importantly, if that earlier population had split into two, say by a land bridge being cut creating two islands from one, then each of the two descendant populations should be accumulating mutations independently of each other—getting more and more different from each other over time—since mutations in one group cannot spread to the other group.  The bigger the accumulated difference, the longer the time they have been separated.

Earlier we created a tree based on comparative anatomy, and saw that it corresponded closely to a tree independently built from the fossil record.  In that example, we looked at representatives from disparate branches, but similar anatomical and fossil classifications of just the primates invariably show that the great apes are very close to each other and to humans, with monkeys being more distantly related, and lemurs further still  (i.e., “more distantly related” means it represents an earlier split, in the same way that the perch, in our earlier diagram, represents a lineage that split off prior to the lizard’s lineage).

With our understanding of genetic mutation and of the large amount of non-functional DNA we can make yet another “tree of life.”  One way to build a tree based on genetic differences is to “unzip” the chromosomes of different species, and take the left half of one species and see how well it bonds to the right half of the other species.    Naturally the bonding will be 100% for the same species.  The greater the genetic similarity, the tighter the bond (measured by heat required to re-separate them).  Here are the results from this DNA-DNA binding technique 3:

Species Percent DNA Binding
Human 100
Chimpanzee 100
Gibbon 94
Rhesus monkey 88
Tarsier 65
Lemur 47
Mouse 21
Chicken 10


This certainly isn’t expected if each kind were separately created, especially when you consider that the vast majority of the sequences have nothing to do with function.  The dead genes, however, provide much more powerful corroboration of evolution than does this impressive result.

Shared Typographical Errors

The discovery of the high proportion of dead or “pseudo” genes provides corroboration of the Descent with Modification hypothesis in a startlingly different way.  To see how, let’s start with an analogy.

Imagine you are a teacher grading essays.  The essays are each a response to the same question you posed to the whole class.  You, of course, made clear to the students that they are to work separately, and that they are not to copy each other’s work.  So how do you tell whether matching passages in some of the returned essays were plagiarized or were just the result of a coincidentally similar choice of words in response to the same question?  What if 30 consecutive words were identical?  Well, that certainly is not likely, but what if in addition all the punctuation marks also matched exactly?  Well, now things are looking even worse for student honesty; but what if in addition to all of that, grammatical, spelling, and punctuation errors match exactly between the two passages and in exactly the same locations?  Well now the odds of a coincidence are so small as to be considered zero.  An extension of this kind of analysis can also reveal whether one person copied from another, or if two students each separately copied from the same third source, and whether each of those “child” copies were themselves copied by others, etc.  The “junk” genes, of which so much of DNA is made, allow just this type of analysis on gene “copying” between species.

As mentioned earlier, mutations can prevent a gene from making anything at all.  A gene is just a long run of code (often made up of thousands of the code letters A, T, C, and G) that when read produces, for example, an entire protein.  If mutations occur at critical locations , then that protein may not be made at all.  Such a mutation would render the whole string of code, of some thousands of letters, “dead.”  Since only a few errors in a string of thousands can make a gene non-functional, then an analysis of the string can often reveal what the gene originally coded for.

For example, humans and the other primates require vitamin C in their diets.  In humans and primates, vitamin C (ascorbic acid) deprivation will lead to debilitating diseases such as scurvy.  “So what?” you ask?  Well, this dependence on vitamin C is the exception among mammals, since, besides primates and the guinea pig, other mammalian species produce an enzyme protein that allows their bodies to synthesize their own vitamin C.  This enzyme protein is called LGGLO (which, if you must know, stands for L-gulono-gamma-lactone-oxidase).  Now, the LGGLO gene that codes for this protein has been identified.

Under the evolutionary hypothesis all mammals inherited the LGGLO gene from a common ancestor.  Any mutation that would render this gene nonfunctional in any of this common ancestor’s descendent species would be pretty rare, and when it did occur it would be fatal unless the gene were no longer needed, such as if the diets of those affected species just happened to be rich in vitamin C.  Now what if one of these descendent species develops a mutation in the LGGLO gene that “kills” the gene—that is, makes it a dead gene?  Well, as I mentioned above, this would only be a problem if the diet of this species is not rich in vitamin C.  Bu what if this species with a dead LGGLO does have a diet rich in vitamin C, and it branches into multiple descendent species of its own over the course of evolution?  Well, now we have a testable prediction.   If Descent with Modification is true, we would expect that this same dead gene would appear in each of those descendent species.  In the case of the primates those descendent species are alive today, and include us.  The prediction is confirmed: that broken relic of a once working LGGLO gene has indeed been found in humans and in the other primates. 4

Now humans and the other primates are believed to share a recent common ancestor based on an enormous array of other converging lines of evidence that have nothing to do with the LGGLO gene—such as morphological, other genetic, molecular, and fossil lines of evidence.  So the additional fact that humans and primates as a group need vitamin C in their diets, and the fact that this condition is extremely rare among the mammals, suggests yet another very specific testable prediction—namely, that the particular genetic “typo” that makes this LGGLO gene “dead” would be the exact same typo in humans as it is in the other primates.  The reason we would expect this is that any number of potential defects can “kill” a gene, so if the defect occurred independently in each primate, then it would be extremely unlikely to be the result of the same typo each time—and it would certainly be completely mysterious why such a cluster of independent events would target the primates as a group when it is extremely rare among all mammals.  This “identical typo” prediction for the primates/human relationship has now been confirmed:  “A small section of the GLO pseudogene sequence was recently compared from human, chimpanzee, macaque and orangutan; all four pseudogenes were found to share a common crippling single nucleotide deletion that would cause the remainder of the protein to be translated in the wrong triplet reading frame.” 5

It is important to see that the strength of this prediction in no way depends on primates being the only group of species with a dead LGGLO gene.  The strength of the prediction comes from two powerful facts: first, that the mutation is extremely rare among mammals but found in all primates as a group (why would this be if the primates are not related?); and second, that for primates as a group the gene is not just dead, but dead from precisely the same genetic typographical error.  Now it shouldn’t be very surprising if we find a dead LGGLO gene in some other mammalian species that does not share a common ancestor with the primates, so long as it is a rare find.  This is so because it is certainly conceivable for a mutation that kills the LGGLO gene to appear independently in another lineage; however, the strong expectation is that if it did occur independently, then the genetic typo involved would be a different typo from the one found in the primates. This is the expectation, for example, in the case of the guinea pig, which is an example of another rare occurrence of a mammalian species with a dead LGGLO gene.

So the LGGLO case is yet another powerful independent line of evidence that converges with so many others.  The creationist has to explain not just how each of these lines of evidence might be wrong, but how, if they are wrong, they all point to the same answer.  Convergence makes appeals to potential errors extremely implausible since it relies on either a fantastic coincidence (that all these errors are just coincidentally consistent with a single theory), or a fantastic conspiracy (that all international universities have been secretly colluding to hide the truth for over a century).  If the LGGLO case is an example of degeneration after the Fall, then why did it just happen to primates and humans as a group in such a way as to independently corroborate that identical grouping constructed from all the other independent sources already mentioned (fossil layering, morphology, etc.) —was it to “test our faith”?

A functional gene that is rendered useless and then persists as a dead gene in the population is rare because most such errors are fatal or horribly debilitating (In the case of LGGLO, the primate diet was rich in vitamin C, so its loss was not a disadvantage).  A more common error found is that of gene duplication, which occurs during the DNA replication process.  It is as if in copying a book someone copies the same paragraph or page twice.  Since one gene is functional, and the copy usually defective and nonfunctional (i.e., dead), mutations can accumulate in the defective copy without affecting the animal carrying it, since they have a second working copy.  Consequently, more of this type of dead gene is found than is the other type.

One example (of many) of duplicated dead genes is the gene that codes for an enzyme that is involved in the metabolism of steroid hormones.  Right next to this gene in humans is a defective copy of the same gene; that is, it’s a non-functional, “dead” copy of the still functional gene right next to it.  Many mutations can render the copy dead; in this case, the particular typo that ruins this gene copy is the deletion of a particular string of just 8 letters (out of a much, much larger number of letters).  Now, Chimpanzees have the same dead gene and here is the “smoking gun”:  Chimpanzees have the exact same 8 letter deletion.6  This is important: they don’t just have the same dead gene, they have the same typographical error that we do in a very large “book” of letters.

Any appeal to “similar design for similar function” is irrelevant here since these are non-functional errors.  Any appeal to “degeneration since the Fall” is also irrelevant, unless one is to assume that God intervenes directly to cause this degeneration by first creating redundant copies of a gene and then targeting particular letters out of many thousands in the genetic code, and only in those animals that are grouped closely together based on comparative anatomy and fossil layering.  Keep in mind that this is only one of many examples of specific typos in the same locations of dead genes that are shared between humans and primates.

Of course, God can do anything (which is why saying “Because God did it that way” explains nothing), but if He did, it only serves to create false corroboration of evolution.  If we allow for that type of explanation, then we can just as easily accept that the universe was created ten minutes ago with our memories in tact, and that all evidence to the contrary is either a test, or just “because God did it that way for His reasons, which we are too lowly to comprehend”).  Again, not only can anything be believed under such an approach, but it also denies us any insights in to the workings of nature since it undermines all of science.

What else did all those dead genes code for?

Those dead and dormant genes code for some strange things, indeed—but unsurprising from an evolutionary framework.  For example, embryonic tissue from the jaw of a chicken was induced to grow teeth.7  Please pause and consider the significance of this: genes for teeth are in the chicken’s DNA, but ignored because the chemical signal that activates them no longer occurs.  Of course, this experiment proves that the genes for teeth are in there.  Why a creator would give chickens the genes for teeth, but keep them turned off, is something difficult to image without the help of a qualified creationist.

To recap up to this point, we’ve seen that a conclusion of descent with modification is corroborated by a tree of life based only comparative anatomy; and again independently corroborated by a tree based only on the position of extinct species in the fossil layers; and again independently corroborated by a tree based only on DNA, which is made up largely of code that doesn’t do anything; and again independently corroborated by the pattern of shared identical typographical errors in the dead genes found in DNA; and again independently corroborated by the kinds of things those dead genes used to code for—things like teeth in chickens, which fits with where chickens are in a tree of life with respect to their toothed, reptilian  ancestors.

Embryology

Earlier I described DNA as a kind of recipe.  This analogy is apt because the form of the final organism depends on the precise timing of various other genes during embryological development.  Indeed, embryological structures are an important factor in identifying homologous structures (as they were for the earlier taxonomists such as the anti-Darwinian, Richard Owen, mentioned above).

A gene typically doesn’t create an anatomical feature all by itself; instead, the feature arises from the action of the gene working in concert with many other genes, and with each operating under a complex schedule of timing.  Modifications of genes that control timing can cause some features to be suppressed, others to be dramatically modified, and still others that are partially developed at one stage of embryological developed to be completely erased at a later stage.  Because genes work in this manner, we would expect that the developing embryo will sometimes reveal certain aspects of its evolutionary past.

Examples of this include the whalebone whale and the anteater, both of whom develop teeth in an early embryological stage only to reabsorb them in a later embryological stage before birth.8 (Actually, this example also demonstrates the presence of teeth genes in yet more toothless animals, like the chicken.)  Terrestrial salamanders at one stage develop both fins and gills, but then lose them before hatching.

Not only do examples like this show the presence of silent genes for characteristics alien to the definition of the species in which we find them, but these dormant traits are consistent with the placement of these animals in the tree of life as having descended from species that did express these traits: birds descended from toothed reptiles, amphibians descending from an ancestral fish, etc.

Of course, this embryological process may not cause complete disappearance of ancestral traits as it did in the above examples.  When they don’t completely disappear, but are still nonfunctional, the structures are described as “vestigial.”  Flightless beetles, for example, have wings that remain forever sealed under permanently fused wing covers.  Even Darwin commented on many such examples, including that of the rudimentary hind legs found in Boa Constrictors.  Seeming to anticipate that some might claim these to have an as yet unknown function, Darwin asked, “why…have they not been retained by other snakes, which do not possess even a vestige of these same bones?”9

Biogeography

This final section is perhaps the most straightforward and certainly one of the most persuasive stand-alone bits of evidence that support Descent with Modification (in other words, even if it weren’t corroborated by all the independent lines of evidence we’ve discussed so far).  Based on Descent with Modification, if one species is the descendent of another, then there had to be some geographical continuity from where the parent species is found to where the child species is found—they had to be able to get there.

Of course, if this geographical continuity were broken at some point in the past, then there are predictable consequences—but only if Descent with Modification is true.  Without going into the many examples of biodiversity that support Descent with Modification, I will focus only on the Australia example, since it alone is such an overwhelmingly persuasive example—particularly against any notion that all of today’s air-breathing species came from one point on the globe, such as from an “Ark.”

Deeper layers of the fossil record show that marsupial mammals (pouched mammals like the kangaroo) were more common than placental mammals (mammals like us that gestate their young inside their bodies with the use of a placenta).  During this time (i.e., in these layers) some parts of the world were populated only by marsupial mammals, including the land mass that would eventually become Australia.  Shallower (more recent) layers of the fossil record show that placental mammals had displaced the marsupials over much of the earth.

But what if a barrier appeared before the expanding placentals could invade a particular area that had been occupied only by marsupials?  For example, what if a peninsula that had been occupied only by marsupials, became an island before the new placentals migrated there?  Well, Descent with Modification would predict that the isolated marsupials might not only survive, but fill many, if not all, of the same ecological niches that placental mammals occupy elsewhere in the world.  In other words, they would evolve many analogies to placentals, and only in one place: their isolated island.

Of course, this is exactly what we see in Australia.  In the table below10, keep in mind that all of the animals in the Marsupial column are more closely related to each other than they are to their counterparts in the other column.  This is an extremely telling observation; it really should make you say, “Wow!”

Consider that the Tiger cat is more closely related to the marsupial mouse than it is to the Bob Cat, which looks superficially almost the same.  The same can be said about the Tasmanian Wolf, which looks almost identical to a “regular” wolf, but is also in fact a closer relative to the Marsupial mouse, who for all the world looks like a “regular” mouse.

Placental Marsupial
Wolf Tasmanian Wolf
Flying Squirrel Flying Phalanger
Mouse Marsupial Mouse
Mole Marsupial Mole
Anteater Numbat
Bob Cat Tasmanian Tiger Cat
Lemur Spotted Cuscus


Keep in mind that all these marsupial species exist in only one part of the world.  Fascinating to be sure, though this is not only explained by Descent with Modification, it is practically expected.  Moreover, it adds yet another independent cross-check of the tree you get based only on the comparative anatomy of marsupials and placentals, which, in turn, is independently cross-checked by the tree drawn only from the layer positions of fossils, which is cross-checked by the tree based on biochemistry, etc., etc.

On the other hand, this is not only completely inexplicable under the creationist “model,” but it actually falsifies that “model.”  What can the creationist say about such a pattern in biogeography?  All they can say is that God created parallel versions of each of these animals (which alone contradicts “similar structures for similar functions”), that they left the Ark at the same time from Mt. Ararat and that somehow the marsupial mouse, Tasmanian wolf, Tiger Cat and the many, many other marsupial species (not shown in the table) that exist only in Australia all cooperated as a group to get to get to Australia ahead of all placental mammals.  As Philip Kitcher puts it,

Some marsupials—wombats, koalas, and marsupial moles, for example—move very slowly.  Koalas are sedentary animals, and it is difficult to coax them out of the eucalyptus trees on which they feed…The idea of any of these animals engaging in a hectic dash around the globe is patently absurd (On the evolutionary account, of course, they are all descendents of ancestral marsupials who had millions of years to reach their destinations)11

If they all started at the same time in the same place, as the creationists claim, what was it about their lack of a placenta that made them move as a group, predator and prey, large and small ahead of very fast placental predators to just this one part of the globe?  Without a direct Divine assist, it’s hard to imagine a coherent explanation.

Conclusion

Let’s think back to the original example of the court case that we discussed at the very beginning.  Can analog watches be wrong? Of course.  Can certain fossils be misidentified, or identified as coming from the wrong layers? Of course.  Can digital watches make mistakes? Definitely.  Are animals sometimes misclassified based on their anatomies? Definitely.  What about the timing of the 5 O’clock news—is it infallible? Definitely not.  What about the reading of DNA sequences—is it infallible? Definitely not.

But just as in the court case, such criticisms miss the whole point.  In the court case example, we don’t believe the suspect is guilty just because of what someone’s watch said, or just because someone heard the 5 O’clock news coming on at 5 O’clock, or just because someone heard the 5 O’clock whistle blow.  We believe it, because what someone’s watch said was the same thing as what the timing of the 5 O’clock news was telling us, which was the same thing as what the timing of the 5 O’clock whistle was telling us.  In other words, we believe because of the agreement between multiple independent sources (not to mention the agreement between multiple samples from the same source—e.g., many watches of different types).

When you find yourself talking about highly technical minutia regarding some particular measurement or method, remember that one particular measurement or one particular method is not why scientists believe that evolution is true.  The critic of Evolution has to show not how a measurement or method may be wrong (we all know that), but how all of the thousands of different measurements using many different independent methods come up with the same wrong answer.  In the court case, ask yourself what the odds are that all those analog and digital watches were all broken in different ways, but still all said 5 O’clock at the same time; and further that this matched the mis-scheduling of the 5 O’clock news, which in turn, coincided with the mis-scheduling of the 5 O’clock whistle.  This conspiracy of errors would have to ensure that as a group they all agreed it was 5:00 PM when it was really, say, 2:02 PM.

It is in fact likely that errors will be made, precisely for the reasons creationists give: these techniques are not perfect.  However, if the prosecution is to have a convincing case, errors should appear as a couple of watches that said it was 4:35 or 5:20, with one perhaps saying it was 11:00 AM, but with the overwhelming majority of independent measurements and methods showing tight agreement around 5 O’clock, plus or minus a minute or two.  Naturally that would be extremely convincing, and the errors would be recognized as statistical outliers—due precisely to the known fallibility of individual measurements.  This is precisely why science doesn’t consider any theory strong on a few data points, but only when there are a many data points and a good deal of independent corroboration.  Keep in mind that errors and unexpected results are reported with the rest of the data.  This is how science accounts for the fallibility of measurements, and the imperfections of individual scientists.

So it is with evolution.  To the creationist one has to ask: How did all the possible errors that could happen in any separate case not only did happen, but conspired together so that as a group they would have tight agreement around the same wrong answer?  That is what we mean by independent corroboration; that is what we mean when we say that a theory is well supported by the evidence; and that is what the critic needs to explain.  Indeed, his or her alternative theory must not only explain the same phenomena, but must account for that agreement, and not simply point to the obvious fact that mistakes can be made, or that some questions remain, as they do in every field of science.


1 Arthur N. Strahler, Science and Earth History: The Evolution / Creation Controversy (Buffalo: Prometheus Books, 1987), p. 108.

2 Adapted from Joel Cracraft, “Systematics, Comparative Biology, and the Case Against Creationism,” in Scientists Confront Creationism, ed. Laurie R. Godfrey (New York: W. W. Norton & Company, 1983), p. 171.

3 Adapted from Strahler, p. 352

4 Edward E. Max, “Plagiarized Errors and Molecular Genetics,” Creation/Evolution XIX (1986) , p. 34.  Reprinted and updated 7/12/99 in TalkOrigins.

5 Ibid.

6 Kawaguchi, American Journal of Human Genetics 50:766-80 (1992), cited in Max.

7 E.J. Ckollar and C. Fisher, Science 207:993 (1980) cited cited in Douglas J. Futuyma, Science on Trial: The Case for Evolution (Sunderland: Sinaur Associates, 1995), p. 48.

8 Stephen Jay Gould, “Evolution as Fact and Theory,” in Science and Creationism, ed. Ashley Montagu (New York: Oxford University Press, 1984), p. 122.; see also, Futuyma, p. 189.

9 Quoted in Futuyma, p. 49.

10 Adapted from Tim M. Berra, Evolution and the Myth of Creationism (Stanford: Stanford University Press, 1999), Fig. 16.

11 Philip Kitcher, Abusing Science: The Case Against Creationism  (Cambridge: The MIT Press, 1993), pp. 141.

A Response to Locke’s, “The Scientific Case Against Evolution”

A reader recently forwarded a link to Robert Locke’s short article entitled The Scientific Case Against Evolution.1The author, while claiming not to be a creationist, certainly writes in the curious even-evolutionists-now-realize style so common among creationist writers.  The article, while not offering new arguments (and not pretending to) does do a good job of succinctly summarizing the current repackaging of the standard creationist themes, so it seemed worthy of a point-by-point response.

Locke’s first claim is that there have always been “distinguished scientists” of “impeccable credentials” who don’t agree that evolution has been proved.  Strangely, Locke’s examples are Richard Owens and, curiously, Steven J. Gould.  Owens was indeed a distinguished scientist—back in the 19th century.  He entered medical school in 1824.  If the credibility of a scientific viewpoint in the 21st century can be established by citing the particular views of scientists living hundreds of years ago, then some very strange ideas would suddenly become “credible.”  Indeed, by reference to the past I could argue that many distinguished scientists refuse to accept the structure of the atom; and if I go back just a bit more I could even argue that many distinguished scientists refuse to accept the roundness of the Earth, or even the fact that the Earth is not the center of the universe.  Certainly, when one wants to give credibility to an idea by showing how mainstream its supporters are, one would do better by referring to the mainstream of modern science.  Darwin’s genius, like Copernicus’s, was not merely that his ideas were revolutionary in his time and supported by the evidence available to him, but that they were also overwhelmingly confirmed by future discoveries, and even by future sciences, becoming not only mainstream, but basic, introductory knowledge for students of the fields.

As for Steven J. Gould, I can do no better than to let him speak for himself:  “…it is infuriating to be quoted again and again by creationists—whether through design or stupidity, I do not know—as admitting the fossil record includes no transitional forms.”2

Of course, there are many, many examples of transitional forms, some of which Gould cites, and many others readily available from any number of academic sources.  It is important to recognize that this anti-evolutionist appeal to “lack of intermediates” utterly depends on there being no intermediates whatsoever.  If intermediates are found at all—even if there are not as many as some of the more extreme gradualist models might suggest—then the criticism is falsified.  As Gould writes,

The supposed lack of intermediary forms in the fossil record remains the fundamental canard of current antievolutionism.  Such transitional forms are sparse, to be sure, and for two sets of good reasons—geological (the gappiness of the fossil record) and biological (the episodic nature of evolutionary change, including patterns of punctuated equilibrium, and transition within small populations of limited geographical extent).  But paleontologists have discovered several superb examples of intermediary forms and sequences, more than enough to convince any fair-minded skeptic about the reality of life’s physical genealogy.3

Gould goes on to describe many of these examples, and elsewhere he even walks through the richly detailed step-by-step, gradual evolution of the whale as revealed by recent fossils4.  Gould’s “punctuated equilibrium” contribution is simply to point out that evolutionary change does not always proceed at a constant rate.   Nonetheless, numerous fossil sequences do show transitionals grading continuously between successive species within the same taxon, and crossing from one taxon into another.  The mammal-to-reptile transition is richly documented, as is the amphibian-to-reptile, and the fish-to-amphibian.  As for transitions between closely related species, one need go no further than the well-known intermediates between humans and our recent common ancestor with Great Apes (e.g. Homo Habilis, Homo Erectus, and the various Australopithecines), whose features are as intermediate as you can ever hope to imagine.  Indeed, it’s puzzling to see their intermediate nature simply denied by antievolutionists, whose rejection seems based on forcing discrete criteria onto what is essentially a continuum.  This tactic simply defines intermediates out of existence, meaning that, a priori, nothing would count as an intermediate.  It is as if I were to claim that color does not exist in a continuum, and when someone showed me something between, say, red and orange, I simply declared it to be in one category or the other (e.g., “It looks more red than orange, so it’s red”).

It is instructive to ask the antievolutionist in such situations for an example of what they would accept as an intermediate—even hypothetically.  Typically, they do one of the following: (1) describe something that is completely inconsistent with evolution, and that if it were actually found, would tend to disprove, rather than prove, evolution; and (2) describe a creature that is intermediate in every feature, which is also not expected under evolutionary theory.  For example, Lock’s comments on the lungfish suggest that he thinks intermediates should be intermediate in all characteristics.  This is simply false.  Intermediates consistent with the actual theory of evolution are precisely what we do find in abundance.

It is very important to understand the difference between evidence that shows that descent with modification occurred (that is, that all life is related somehow through common descent in a “tree of life”) and evidence for or against particular mechanisms and tempos by which it occurred.  I refer you to my article on evolution at Evolution: Converging Lines of Evidence for more on this critical distinction, which antievolutionists, including Locke, repeatedly ignore.  These antievolutionists repeatedly confuse the mainstream scientific criticisms of some theory of mode or tempo (e.g., Gould’s attack on steady-state gradualism) as an attack on evolution itself (i.e., descent with modification).  This is worse than false, and represents a serious misreading of fundamental evolutionary concepts.  Supposed “critics” of evolution (like Gould) slap their heads at this, and write pointed rebuttals like the one cited earlier, but they are simply ignored.  Contrary to what Locke cites Denton as saying, the fossil record has amassed far more evidence than is necessary to prove that all life is in fact related through common descent. None of this evidence puts descent with modification in doubt at all—quite the contrary: the number and range of transitional forms is now quite large and still growing.  But the proof that evolution has occurred goes far beyond the fossil record or any one line of evidence (see Evolution: Converging Lines of Evidence ).

Locke goes on to say, “The problem with this theory [punctuated equilibrium], which is too complex to go into in detail here, is that while it explains away the non-existence of small gradations, it still requires there to be large ones (the individual spurts) and even these aren’t in the record.”  It’s unclear what he means by “individual spurt” since individuals don’t evolve, populations do.  In any case, this is a rather egregious misreading of Gould.  As my earlier quote shows, Gould, and evolutionists in general, hardly believe in the “non-existence of small gradations.” Gould cites many of his own examples, which barely scratch the surface of the examples readily available.  And about his theory requiring large gradations, Gould goes on: “Continuing the distortion, several creationists have equated the theory of punctuated equilibrium with a caricature [that] major transitions are accomplished suddenly by means of ‘hopeful monsters.’”5  Gould then goes on to quote Duane Gish as claiming that Gould believes a reptile laid an egg from which a fully formed bird emerged, to which Gould remarks, “Any evolutionist who believed such nonsense would rightly be laughed off the intellectual stage.”6  Locke is not clear as to how large a “spurt” he is referring to, but the idea that Gould believes that significant evolutionary change occurred through such sudden jumps is simply false. (Perhaps Locke is misunderstanding the significance of the uncontroversial fact that some genes have a more dramatic effect on morphology than others, and these genes can also be affected by natural selection.)  Punctuated Equilibrium simply argues that the tempo of evolution is often relatively rapid when speciation is occurring, since it argues that speciation often occurs when small groups are isolated, with stasis being the rule otherwise.  But “rapid” or “sudden” here is used in the geological sense, not in a literal everyday “overnight” sense of the word.  By “rapid” Gould means tens of thousands of years.  But since a single species can be depositing fossils for many millions of years, the speciation period can represent considerably less than 1% of that time span.  And despite that, we still have many examples of transitional fossils.

Locke’s comments on computers reveal a misunderstanding of cladistics and neglect of a vast literature showing the incredible contributions to, and logical validation of, evolutionary theory that computers have provided.  The burgeoning fields of artificial life, genetic algorithms, and evolutionary programming exist only because natural selection and descent with modification are logically coherent concepts and describe highly creative processes. (If Darwinism were the tautology some creationists claim it to be, then one couldn’t simulate it in software and expect it to do anything.)  These sciences depend on creating a virtual world where neo-Darwinism can be instantiated.  This is done by creating the software equivalents of genes, random mutation, random genetic recombination, and environmental forces that affect the relative “fitness” of the resulting gene combinations.  Famous examples of these include “Tierra,” and “Polyworld.”   (In Tierra, parasitic life forms unexpectedly evolved to the utter astonishment of Tierra’s programmers.  Even more astonishing was the evolution of an immune response to these parasites and an ensuing “arms race” between these emergent species.)7  Such techniques are even now being used in industrial applications to allow evolution to “design” solutions to engineering problems, like coming up with efficient aircraft wing shapes.  These facts refute in a stroke all attacks on evolution based on supposed logical incoherence or meaninglessness (such as the circularity/tautology objection).  In my other evolution article, Evolution: Converging Lines of Evidence, I discuss cladistics in more detail, and show why Locke is quite mistaken when he claims that an evolutionary tree is only the result of “pattern craving” human minds.

Locke also states that, “…if different species have common ancestors, it would be reasonable to expect that similar structures in the different species be specified in similar ways in their DNA and develop in similar ways in their embryos; this is frequently not so.”  Without examples, it’s difficult to understand what he is asserting.  For example, all life shares a common ancestor—if you go back far enough.  If two species share a recent common ancestor, such as modern humans and chimpanzees do, then much is indeed “specified in similar ways,” and “develop in similar ways in their embryos.”   But where the common ancestor is much further back, the expectation naturally changes.  Indeed, the case of the evolution of the whale is one of a creature who can trace its ancestry onto land, and then, if you go back further still, back to the sea yet again.  Does this mean that its “fins” should be like a fish’s fins because all life shares a common ancestor?  The answer, of course, is no.  Locke’s comment here seems to reveal a misunderstanding of the significance of homologous and analogous morphologies in evolutionary theory.  Indeed, it is evolution that predicts and explains what we do in fact see in the natural world.  This subject is also covered in more detail in the previously mentioned article.

Locke’s comments on the horse are a bit vague as well.  He seems to be saying that the earliest horse and the modern horse are too similar to each other, and so showing a gradual transition between them doesn’t prove much, yet he seems to question the transitional evidence regardless.  Of course, the earliest “horse” is a little, terrier-sized forest dweller called Hyracotherium, which lived some 54 million years ago (mya).  Is he saying it is a horse in order to be able to declare that the transition evidence doesn’t prove much?  Whether you choose to call Hyracotherium a horse or not, presumably one still needs to explain the process by which it so dramatically changed over those 54mya.

When Locke says, “And even the emergence of one species from another has never been directly observed by science,” he reveals a serious misunderstanding of the scientific method itself—as it applies to all of science.  Surely, science is more than simply reporting what we directly observe; in fact, science is all about using what we can see to predict and describe what we cannot see.8  For example, no one has “observed” electrons orbiting the nucleus, or seen the inside of the sun, or even seen germs actually making a living human sick (we only observe the illness at work under a microscope in a lab).  Regardless, we can know these models describe reality when the models make successful predictions (e.g., “if the atom has structure x, then i, j, and k should be true—are they?”).  Locke’s is the type of criticism that, if accepted, would require our throwing out not just evolution but much of physics, astronomy, geology, and the other physical sciences, not to mention our rules of evidence in courts of law.  Indeed, though I would suspect Locke and others using this argument do not realize it, it is an anti-reason argument.  If direct observation were the only way we could be sure of anything, then our legal system would be in jeopardy, since the only evidence acceptable would be eyewitness testimony—no genetic, no fingerprints, no hair, no physical evidence whatsoever, since none of that bears on direct observation of the crime actually happening.  Clearly, there is something wrong with this line of criticism.  Yet, despite the fact that direct observation of an event is not necessary in order to know that an event really happened, speciation has been directly observed in the lab on multiple occasions.

Locke also brings up a classic of creationist argumentation:  the “can’t get there from here” charge.  This is illustrated by the “half of a wing,” or “half of an eye” example.  Sometimes this is called the “irreducible complexity” argument.  All forms of this argument are based on a serious confusion as to what evolutionary theory is actually saying.  First, it’s important to understand why half wings are not predicted by evolution.  In fact, if we ever did find evidence of a species with what amounted to modern wings but “chopped in half” (as if waiting to “evolve” the other half), then evolutionary theory would actually have a big problem on its hands.

Natural selection operates only in the immediate, local environment—it has no intelligence, no purpose, and no ability to see even one generation into the future.  Novel gene combinations, additions, or mutations, will spread in a population only if they increase the odds (even slightly) that the affected offspring will live long enough to make babies. This is just a mathematical property of the system:  Since offspring with these “helpful” genes are more likely to make babies, more babies in the next generation will have these genes—since they inherit their genes from their parents.  And the number of babies with these genes will keep increasing in each generation as long as these genes continue to be helpful.  (This lack of foresight in natural selection is also why evolution cannot “go back” and redesign something; it can only work with what is at hand.)

This means that useless partial stumps of would-be “future” wings, or anything else, would get in the way, as so be selected against.  So, when we do see useless appendages (like the vestigial leg bones inside some snakes), they represent the withering away of the creature’s past features that are no longer useful; they don’t represent the “embryo” of some future characteristic.  As a result, we expect that all life forms, ancient and modern (which includes what we call “transitionals”) to be generally well adapted to their environments.  It’s not as if today is the day that all species were working toward and are now finally “done” evolving, while in the past they were only “half way” there.  There is nothing special about now as opposed to the distant past or the distant future.  In the distant future, species that appear “complete” to us now will probably be described as transitional by future paleontologists—they might even be talking about our species.

So what about birds and their wings?  How can they have been adapted to their environments in the past if they couldn’t even fly?  The answer is that the ancestors of birds were adapted to a completely different environmental niche than their modern-day descendents, one that had nothing to do with flying.  Characteristics that would later support flight, like feathers, originally appeared for a completely unrelated reason, perhaps for something like insulation—a purpose that had immediate benefit.  Remember, potential future usefulness doesn’t count.  Basically, a new incipient structure can arise (a) because the genes that produce it are being selected for a completely different reason—generating the incipient structure like a side effect, which is then able serve an unrelated purpose of its own; (b) because it directly intensifies some ability or function; or (c), because the structure was used for one thing but is now being used for something else, which makes it subject to completely different selective forces.  Note that this predicts that creatures should be readily found that are inefficient in their designs, which is easy enough to do (look at a Panda’s “thumb” or the bizarre embryological processes that I cite in my other article).

To clarify this very important point, let’s use an analogy:  Think of the hypothetical “evolution” of a brick arch-bridge.  First, there’s no need for a bridge, there is just a pathway.  But farms on each side of the pathway want to keep their cows in, so they put up fences.  A mild earthquake creates a small crack, but people can still jump over it easily enough.  But the crack widens over time, so some fence planks that are no longer needed are taken down and laid across the crack.  As the crack widens, the planks begins to sag, so scattered bricks that have fallen from passing wheelbarrows are collected and stacked in columns beneath it for support.  Initially, just a few bricks in single column are sufficient, but over time the crack continues to widen and deepen. As a result, gradually more and more stacks of bricks are added so that the supports eventually form a wall, like a dam.  Eventually, increasingly heavy water flow through this ever deepening fissure knocks out some of the lower bricks; however, the bridge doesn’t need to be repaired because the upper bricks that used to be supported by these lower ones have now become equally well supported sideways by their ever-pressing neighbors.  The lower bricks from the center of the span are allowed to wash away leaving an arch connecting either side of the creek.  A creationist then comes along and points out that this must have been designed and built in one event as an arch bridge; after all, an arch bridge is “irreducibly complex”: what good is half and arch? Indeed, what could have held up half an arch?  Well, in this case there never was half an arch. There were intermediate structures that served other purposes and worked well enough in their day.  At each point in its history the bridge structure was “complete.” At each step minor steps were taken for immediate needs using only the materials that were on hand at the time.  And at no point was there a grand design, or an end game in mind.

This crude analogy shows how evolution can inadvertently create what amounts to “scaffolding,” which can disappear when it is no longer needed, leaving a free-standing structure that would collapse if any of its current parts were missing—creating what appears to be an irreducibly complex structure.  This would apply not only to morphological structures, but to chemical processes as well.  This explanation is not revolutionary, and can be see at work in the fossil record in cases such as the formation of mammalian ear bones from parts of the reptilian jaw.

Locke’s comments regarding the findings from microbiology (i.e., protein comparisons) are difficult to make sense of, unless he misunderstands what he is describing.  Surely, Locke understands that all proteins, and by extension all genes, are not expected to diverge equally in proportion to evolutionary distance.  The degree to which different proteins can diverge is a function of the nature of the protein and its role.  Some proteins can fulfill their functions with a wide variety of amino acid substitutions (which trace back to gene substitutions), others cannot.  Those that cannot would not be expected to show much change at all, even in “deep time,” and their conservation over time (and therefore across widely disparate species) is expected; it is a result of what is called “purifying selection.”  However, those proteins that are functionally unconstrained do accumulate differences, and do so in proportion to their evolutionary distance—it is this fact that is explained only by evolution:  Why would functional, unconstrained proteins diverge only in proportion to evolutionary distance?  The evidence from microbiology here is truly vast, and conclusive on its own, and I mention some of the most powerful of it in my other article.

The “can’t get the ball rolling” argument that Lock makes is, of course, irrelevant in a very important sense:  The evidence that life shares a common ancestor is completely independent of any theory as to how the root of that tree of life “got started.”  Indeed, many evolutionists are Christians, or other types of theists, and believe that God got the ball rolling.  Nonetheless, there are very plausible accounts (Nobel Laureate Christian de Duve has an interesting one in his book, Vital Dust9), though not enough evidence yet exists to conclusively support one plausible path over another.  Telling experiments, such as Stanley Miller’s, hint at pieces of the answer by showing, for example, how natural inorganic processes can form the amino acid building blocks of life—spontaneously.  No specific path may ever be found, but the evidence that evolution occurred is quite independent of that question.  We can know that it happened without knowing all the detail of how it happened, and the evidence that it happened is overwhelming and conclusive.

Locke’s call for intermediates is also quite misplaced here.  Archaic bacteria have been found and their genetic differences from the rest of the living world are as profound as one would expect under the evolutionary model.  What’s more is that these ancient life forms find oxygen utterly poisonous.  We know from geological evidence that huge periods of our past were oxygen free.  This fits well with the idea that an oxygen-rich atmosphere would have destroyed that early life and any earlier “proto-life.”  When these early bacteria multiplied beyond a certain point, their own waste – oxygen – killed most of them off from everywhere except their current exotic, oxygen-free environments; others not only learned to tolerate oxygen, but also got to a point where they needed it.  The bottom line is that the world is a very different place now than it was then.  The presence of oxygen would be highly corrosive to the kinds of complex molecules that might represent the intermediates between life and non-life, dissolving them almost immediately.  As in our arch-bridge example, the “scaffolding” that such prebiotic intermediates represent may well have long since washed away, and the world is now far too poisonous (oxygen rich) a place for them to ever appear again.  All we may be able to do now is infer their existence.  But such inferences can be as conclusive as the inferences that tell us of the structure of the atom, or the guilt of a criminal in a court of law.

Locke also makes a passing reference to the “odds” of any of it happening by “chance.”  When he uses the phrase, “too complex to have been thrown together by any known non-living chemical event,” he demonstrates a common misapplication of probability theory to this subject.  For a discussion of the flaws in such misapplications of probability, I refer you to my article on Complexity, Probability, and God.

Locke also mentions Karl Popper.  I can only assume Locke is unaware that Popper’s critique was never of descent with modification, but of natural selection, and he admitted that he was mistaken even in that once he learned a bit more about the subject.  Popper has always said that Darwin’s core thesis—that all life is related through descent with modification—was not only testable, but was the most successful explanation of all the data.  Indeed, he considered Descent with Modification to be “historical fact.”10  Locke’s sources are seriously misinformed.  Regarding natural selection, Popper retracted his tautology charge, pointing out that natural selection “can be so formulated as to be far from tautological.”11  Popper was of course right that some people do come up with untestable natural selection stories (Gould called these “just-so” stories) about how some physical feature or other came to be.  Misapplication, or untestable speculation, based on the concepts of an otherwise proven theory is not evidence against the theory anymore than making untestable speculations about how some physical event may have happened, amounts to evidence against physics.  To suppose that is does is to suppose these speculations provide the evidence for the theory, which of course, they do not.

Ironically, it is creationism that fails Popper’s falsifiability criteria, not evolution.  In my evolution article I make clear how evolution (descent with modification) is repeatedly falsifiable and yet resoundingly passes these tests.  Creationism, however, isn’t even a theory. (As someone once put it, “It’s not even wrong.”)  It seems little more than a set of mutually contradictory and ill-informed attacks on evolution.  Stripped of this negative content, it has no substantive positive content of its own beyond saying, “things are the way they are because God must have wanted it that way.”  What does that predict?  How does a scientist use such a “theory” to gain additional insights in the lab or in the field? What could conceivably count as evidence against it?

I cannot bring myself to let Locke’s analogy between evolution and Newtonian physics get by.  Certainly, the evidence that supported the validity of Newtonian physics was vast and convergent, just as it is with evolution.  It is also true that Newtonian physics was later discovered to be a special case of a more general theory of physics, called relativity.  But this in no way suggests that Newtonian physics was falsified.  What it does mean is that Newton’s formulas and theories remain true over the domain of problems to which the theory is applied, and while he imagined that it would work in even the most extreme circumstances, it turned out other factors become more dominant in those extremes.  Such advancement is what science is all about: building on, rather than erasing, the work of others.  Indeed, we use Newtonian mechanics today, and not relativity, to put people on the moon, to design our airplanes, our cars, our satellites, and our buildings.  If evolution were found to be a special case of a broader theory in the same way that Newtonian mechanics was, then it would not be much of a cause for antievolutionist celebration.

I have to conclude that Locke’s “Scientific Case” not only fails to make its case, but is not very scientific.  His claim of a “major trend” in biology against evolution would come as a surprise to biologists the world over, and his evidence to support this claim is either hundreds of years old, or is based on rather gross (though, I’m sure, unintentional) misrepresentations, of both science and individual scientists.  It brings up old, unoriginal arguments that have long-since been discredited—arguments based on misrepresenting scientists’ views, misrepresenting evolutionary science, and even misrepresenting the scientific method itself.   Indeed, my Gould quotes date back to the mid 1980’s (Popper’s retraction dates back to the 1970’s) and yet almost a quarter century later we continue to see antievolutionist / creationist writings misquoting and misrepresenting his work in exactly the same way they did back then, without even a passing acknowledgement of Gould’s repeated and forceful refutations of these same misrepresentations of his hard work.  (Even if Locke is not a creationist or “antievolutionist,” he uses and draws upon sources that use their discredited arguments and misrepresentations.)  Such is yet another reason why creationism is not considered science at all.


1 Robert Lock, “The Scientific Case Against Evolution,” 5/2/2004,  <http://www.godandscience.org/evolution/locke.html>

2 Steven J. Gould, “Evolution as Fact and Theory,” in Science and Creationism, ed. Ashely Montegu (New York: Oxford University Press, 1984), p. 124.

3 ibid.

4 Steven J. Gould, Dinosaur in a Haystack: Reflections in Natural History (New York: Random House, 1995), pp. 359-376.

5 Gould, “Evolution as Fact and Theory,” p. 124.

6 ibid.

7 A good introduction to the field is Steven Levy, Artificial Life: A Report from the Frontier Where Computers Meet Biology (New York: Random House, 1992).

8 Excellent discussions of this point in Philip Kitcher, Abusing Science: The Case Against Creationism (Cambridge: MIT Press, 1993).

9 Christian DeDuve, Vital Dust: The Origin and Evolution of Life on Earth (Basic Books: New York, 1995)

10 Quoted in Robert T. Pennock, Tower of Babel: The Evidence against the New Creationism (Cambridge: MIT Press, 1999) p. 100.