Camp Answers Theobald
Reply to Theobald’s Response to Part 1 of Critique
By Ashby L. Camp Copyright 2002 by Ashby L. Camp. All rights reserved. In “29 Evidences for Macroevolution,”[1] Douglas Theobald asserted that the hypothesis of universal common ancestry had been proven scientifically because 29 falsifiable predictions of the hypothesis had been fulfilled. I explained in my critique of his article why that is not the case. Dr. Theobald has now posted a lengthy rejoinder to the first section of my critique, accusing me of devious tactics, widespread ignorance, and a host of intellectual sins. I leave it to the reader to judge the fairness of those charges.
Prediction 1: The Fundamental Unity of Life
Dr. Theobald’s main argument under this section is that the hypothesis of universal common ancestry predicts that all creatures will have in common the structures and mechanisms that perform the following basic life functions: replication, information flow in continuity of kind, catalysis, and energy utilization (metabolism). As I showed in the critique, that is not a falsifiable prediction of common ancestry.
If different structures and mechanisms for basic life functions were discovered in creatures A and B, and if proponents of common ancestry admitted they could not imagine how both organisms could have descended from a conventionally assumed ancestor, they could still preserve their theory in one of two ways (or a combination thereof). First, they could claim that the inability to imagine a chain of descent from such an ancestor is merely a function of our ignorance, a matter for further research. In other words, they could treat it the same way neo-Darwinists treat the inability to imagine the steps through which allegedly irreducibly complex structures and systems evolved.
Second, they could take the difference between A and B as an indication that the common ancestor must have been different than is conventionally believed. If, for example, one assumes that the universal common ancestor lacked DNA and RNA (per Shapiro) or that it was a crystalline clay organism (per Cairns-Smith), it opens new avenues of evolutionary imagination and speculation. In an evolutionary framework, the claim that a hypothetical organism of unspecified traits gave rise to both A and B cannot be disproved. So the claim that the discovery of creatures A and B would falsify the hypothesis of common ancestry is incorrect.
Dr. Theobald accuses me of constructing a straw man because I said his argument was that the hypothesis of universal common ancestry predicts that all organisms will have one or more traits in common. He claims that this summary phrasing weakens his argument by omitting the fact he specifies that the traits all organisms must have in common relate to the basic functions of life. He then quotes “from the original prediction 1” to verify that his claim was more specific. (In saying that he was quoting “from the original prediction 1,” Dr. Theobald may leave the casual reader with the false impression that those comments were not included in my paper. The fact is that I quoted his alleged prediction in its entirety.)
Even if I had not quoted Dr. Theobald’s prediction in its entirety, I do not see how my summary phrasing qualifies as a straw man, given that it encompasses the claim being made. If one argues that two bullets must have come from the same gun because they have certain striations in common, would it be a straw man to say the claim was that the two bullets must have come from the same gun because they have one or more traits in common? Specifying the traits (striations) does not affect the nature of the argument, which is that an inference can be drawn about origins on the basis of similarities.
Dr. Theobald next accuses me of confusing gradualism with the concept of evolutionary mechanism. To appreciate what is going on here, one must recall that Dr. Theobald claimed in his article to prove universal common ancestry “independent of any explanatory mechanism.” He wrote that his proof did not depend on “whether Darwinism, Lamarckism, or something else is the true mechanism of evolutionary change or not” (emphasis supplied). I pointed out that a bare claim of universal common ancestry, one that is independent of any mechanism of descent, is compatible with all mechanisms of descent, including divine direction.
I noted in my critique (footnote 1) that Dr. Theobald contradicted his claim to argue for common ancestry without regard to any particular mechanism by including in his definition of macroevolution the requirement of gradualness. He is now trying to deny that contradiction by arguing that gradualness is not a mechanism. The point, however, is that the requirement of gradualness restricts the universe of mechanisms. So if one’s argument for common ancestry assumes gradualism, one is not arguing for common ancestry “independent of any explanatory mechanism.” Rather, one is making an argument for common ancestry that is dependent on gradual explanatory mechanisms.
It is in that context that I wrote:
Dr. Theobald understandably seeks to free the claim of universal common ancestry from the debate about the sufficiency of evolutionary mechanisms, particularly the debate about neo-Darwinism. It should not go unnoticed, however, that a bare claim of universal common ancestry is compatible with all mechanisms of common descent, including divine direction. So if God chose to have a reptile give birth to a bird, for example, that would be consistent with an “amechanistic” argument for universal common ancestry.Rather than acknowledge that he overstated his case, Dr. Theobald ignores his contradictory statements and blames me for not knowing that he really meant to restrict the explanatory mechanisms to gradual ones. If that was his intent, he should not have claimed that he was arguing for common ancestry “independent of any explanatory mechanism.” He was trying to have his cake and eat it too.
Contrary to Dr. Theobald’s assertion, I do not “paradoxically” criticize the constraint of gradualism in footnote 1. I point out that the constraint contradicts his claim to argue for common ancestry independent of any explanatory mechanism. Nor am I wrong in saying that Dr. Theobald does not address the sufficiency of accumulated observable variation to account for universal common ancestry. He speaks of observable variations, but he simply assumes they can be extrapolated across all biological divides.
Dr. Theobald next charges me with presenting a red herring because I included in a quote from Walter ReMine a statement that evolution does not predict that life would arise only once on this planet. The accusation is silly. I state in the introduction that “Dr. Theobald does not address the origin of the first living thing,” and I state in the footnote accompanying ReMine’s quote that “Dr. Theobald assumes a single origin of life, so this comment is beyond the scope of his paper.” I also explain in the footnote that I included the comment “to provide context for the remainder of the quote.” I simply did not want the quote to begin with “Second, . . .”
Dr. Theobald accuses me (and, indirectly, Walter ReMine) of ignoring “the fundamentals of biology and the constraint of gradualism” in denying that common descent predicts biological universals. He states:
Common descent does predict specific biological universals, since any significant change (any “loss and replacement processes”) in the structures that perform the four basic life functions would result in nonviable organisms; these structures cannot be lost nor can they be replaced (although they can be expounded upon). Once life attained these specific structures (by whatever process), they were essentially frozen.When neo-Darwinists are confronted with structures and systems that are alleged to be irreducibly complex, they scoff at the claim by appealing to the possibility of an undiscovered pathway through which such systems and structures could have been constructed incrementally. A proponent of universal common ancestry could make the same argument regarding structures that perform basic life functions. That is, he could say that just because we do not yet understand how viability could have been maintained during the incremental construction of those structures does not mean that the chain did not exist. When one adds the option of varying the traits of the hypothetical ancestor, such as assuming that it possessed no organic molecules, the room for speculation is boundless.
After offering an unhelpful analogy, Dr. Theobald says:
[G]iven the fact that we now know that all organisms studied to date, including bacteria and birds, have a very similar glycolysis metabolic pathway (or genetic code), we can use common descent to predict that all undiscovered or unexamined organisms that fit between bacteria and birds in the standard phylogenetic tree will also have a similar glycolysis metabolic pathway (or genetic code).The point is that finding an organism with a dissimilar glycolysis metabolic pathway or genetic code would not falsify the hypothesis of universal common ancestry. The discovery could be accommodated by the theory in several ways, as I have explained. So Hunter is indeed correct when he says:
Consider how evolutionists would react if there were in fact multiple codes in nature. What if plants, animals, and bacteria all had different codes? Such a finding would not falsify evolution; rather, it would be incorporated into the theory. For if the code is arbitrary, why should there be just one? The blind process of evolution would explain why there are multiple codes. In fact, in 1979 certain minor variations in the code were found, and evolutionists believe, not surprisingly, that the variations were caused by the continuing evolution of the universal genetic code. Of course, it would not be a problem for such an explanation to be extended if it were the case that there were multiple codes. . . . When it comes to the genetic code, evolution can accommodate a range of findings, but it cannot then use one of those findings as supporting evidence. (Hunter, 38.)Dr. Theobald admits that biochemical similarity fits easily within the creation framework, but he considers that meaningless because the creation framework can accommodate any data. Yet, the same can be said of the hypothesis of universal common ancestry. One committed to that theory (“the fact of evolution”) can interpret the data consistently with the theory. As Hunter says: “There is nothing wrong with a theory that is comfortable with different outcomes, but there is something wrong when one of those outcomes is then claimed as supporting evidence. If a theory can predict both A and not-A, then neither A nor not-A can be used as evidence for the theory.” That is what Dr. Theobald is doing.
Dr. Theobald asserts that ReMine’s biotic message theory is compatible with universal common ancestry, despite recognizing that ReMine disagrees with him. It is a bold man indeed who claims to understand ReMine’s theory better than ReMine. In claiming that ReMine’s theory is compatible with common descent because a single designer could “have used evolution to make all of life look like a unified work,” Dr. Theobald reveals a misunderstanding of ReMine’s work. The unity of life is only part of message theory. The theory asserts that life was designed simultaneously for survival, to look like the product of a single designer, and to resist all macroevolutionary explanations.
In illustrating how biochemical similarities might be part of a Creator’s design, I quoted Duane Gish for the point that the similarities might have been to permit humans to eat plants and animals. Dr. Theobald rightly remarks that I (through Gish) overstated the matter in suggesting that this was a necessary rather than merely a conceivable divine rationale. The point, however, is that biochemical similarities are compatible with a creation viewpoint, something Dr. Theobald concedes.
Dr. Theobald ends this section by accusing me of constructing another straw man when I wrote: “The claim that all organisms have one or more traits in common is true in the sense that all living things necessarily have the traits by which life is defined, but that is simply a tautology - living things all have the traits of living things.” He says he was not claiming that living things have the functions of living things, which he agrees would be a tautology, but that living things have similar structures and mechanisms that perform the functions of living things.
The fact is that he made both claims. He stated under the prediction: “If every living species descended from an original species that had these four obligate functions, then all living species today should necessarily have these functions” (emphasis supplied). For exposing that tautology, I am accused of chicanery.
Prediction 2: A Nested Hierarchy of Species
Dr. Theobald claims that the nested hierarchy of existing species[2] fulfills a falsifiable prediction of the hypothesis of universal common ancestry and therefore constitutes evidence that the hypothesis is true. I argued that, because descent from a common ancestor does not necessarily result in a pattern of nested hierarchy, the hypothesis of common ancestry would not be falsified if organisms did not fit that pattern. That is, a nonhierarchical pattern could be explained consistently with common ancestry by appeal to processes that work against a nested hierarchy. Dr. Theobald accuses me of error in claiming it is possible for descent from a common ancestor to result in a non-nested pattern. He is wrong.
There are various ways in which existing organisms could descend from a common ancestor and not exhibit a nested hierarchy. Anagenesis, loss of characters, replacement of characters, transposition of characters, atavism (masking and unmasking), and convergence all work against a hierarchical pattern, and the bare hypothesis of universal common ancestry says nothing about the rate or prevalence of those processes. They can be invoked in whatever blend is necessary to explain whatever pattern is found. Therefore, the claim that the hypothesis of universal common ancestry makes a falsifiable prediction that organisms will exhibit a pattern of nested hierarchy is incorrect.[3]
Indeed, Dr. Theobald acknowledged in both prediction 2 and the response to my critique that Lamarck’s organic progression would yield a non-nested pattern of organisms. Since he claims to prove universal common ancestry regardless of “whether Darwinism, Lamarckism, or something else is the true mechanism of evolutionary change,” he cannot offer evidence that depends for its probative value on the exclusion of any of these mechanisms. In other words, since Lamarck’s organic progression (to pick one example) admittedly does not predict a nested hierarchy, a nested hierarchy is not evidence of common descent via Lamarck’s organic progression. Therefore, it is not evidence of common descent regardless of “whether Darwinism, Lamarkism, or something else is the true mechanism of evolutionary change,” which is the proposition being argued by Dr. Theobald.[4]
I suggested that the hierarchical pattern of life is compatible with divine creation of separate kinds by pointing out (through Hunter’s quote) that Linnaeus, the father of biological classification, saw them as compatible. In response, Dr. Theobald attempts a reductio ad absurdum, claiming that this reasoning would cast doubt on Newton’s theory of gravity. He writes:
According to [this] twisted logic, Newton’s theory of gravity is also suspect. It has been known since long before Aristotle that apples fall to the ground when dropped. People before Newton, such as Aristotle, thought that apples were attracted to the earth because they were primarily made of the “earth” element. Obviously this pattern (falling) does not force one to embrace the inverse square law. The fact that people were wrong about physical explanations in the past is not an argument against modern scientific theories.In his rush to criticize, Dr. Theobald misses the mark completely. I do not use Linnaeus’s belief in separate divine creation (multiple ancestors) as evidence that universal common ancestry is false. Rather, I use his simultaneous belief in nested hierarchy and separate divine creation as evidence that those two are logically compatible. In terms of Dr. Theobald’s analogy, I am citing the fact Aristotle believed in both falling and elemental attraction as evidence that those beliefs are compatible, not as evidence that Newton’s theory is false. (His analogy is confused a bit more by the fact the inverse square law is really a description or quantification rather than an explanation.) Since Dr. Theobald recognizes that the phenomenon of falling is compatible with multiple explanations, he should have no objection to the point.
Dr. Theobald accuses Hunter (through my quoting of him) of misrepresenting evolutionary theory in claiming that the principle of divergence is distinct from common descent. According to Dr. Theobald, Darwin’s principle of divergence is simply another name for (“is otherwise known as”) common descent. That is incorrect. The principle of divergence was an addition to the bare notion of common descent that “Darwin believed necessary to account for the diverging, tree-like relationships of organisms” (quote from the Darwin Project at the University of Cambridge, http://www.lib.cam.ac.uk/Departments/Darwin/intros/vol6.html). For my part, I misunderstood that Darwin’s principle of divergence related to a specific pattern of nested hierarchy, not to nested hierarchy in general.
Dr. Theobald suggests that I am confused about whether common descent must include branching because I stated, “Even a mechanism of descent that includes branching events does not ensure a nested pattern.” He asks, “If multiple species evolved from a common ancestor, how could they have arisen without branching?” Of course the coexistence of multiple species requires branching. I simply was acknowledging that there is a mechanism of descent (anagenesis) that does not include branching, while making the point that cladogenesis would not guarantee a nested pattern (for the reasons given above).
After quoting from my critique ReMine’s assertion that nested hierarchy is not an inevitable consequence of common ancestry (because of various processes that can work against that pattern), Dr. Theobald writes:
ReMine thinks that since there are certain conditions under which a prediction of our theory will not be observed, then observing the prediction is not a confirmation of our theory. If this were true, we could never confirm any scientific hypothesis, not just common descent, since there are always certain conditions under which we will be unable to observe some consequence of a theory. . . . ReMine simply does not understand how the scientific method works.This is a mischaracterization of ReMine’s position. ReMine is not claiming that fulfillment of a theory’s falsifiable prediction (e.g., the mutual attraction of two masses decreases in proportion to the square of the distance between them) is nullified by an inability to test the prediction under certain circumstances (e.g., where the attraction is predictably below measurable limits). Rather, he is claiming that nested hierarchy is not a falsifiable prediction of common ancestry because the theory includes without restriction processes that work against that pattern. Those processes can be invoked in any blend to account for any non-nested pattern that is observed.
Next, Dr. Theobald chides me for quoting “another confused anti-evolutionist, Michael Denton.” As an aside, I find it fascinating that, according to Dr. Theobald, Denton “doesn’t understand even the most fundamental evolutionary concepts.” It is fascinating because one often hears that nothing in biology makes sense except in light of evolution. And yet, Denton, being ignorant of the most fundamental evolutionary concepts, managed to earn a Ph.D. in developmental biology (in addition to an M.D.), to write or co-author over seventy articles in professional journals, and to work for decades as a genetics researcher. Apparently knowledge of evolution is irrelevant to a career in science.
Dr. Theobald’s disparaging comment notwithstanding, Denton’s point about the nested hierarchy observed in nature has merit. The discreteness or discontinuity of the groupings does not flow naturally from a random, undirected evolutionary process. One must explain why the morphological space between the groups exists, as opposed to the divisions being blurred and indistinct. The point is not that evolutionists cannot explain it but that it is something that requires an explanation.
Dr. Theobald apparently misunderstands Denton’s point in the quote, as he claims that Denton subsequently contradicted himself in opining that the hemoglobin gene cluster in primates was not discontinuous. Just because Denton believes there is no discontinuity requiring an explanation in that particular instance does not mean he denies there is discontinuity elsewhere. So Dr. Theobald’s comment (“One wonders how Camp can feel justified in quoting Denton’s past confusions about common descent”) is misguided.
Dr. Theobald next charges me with wrongful imputation of a theological assumption. He writes: “In fact, no theological assumptions or arguments are made at all in the essay. The ‘29 Evidences’ is not an argument against creation—it is the scientific argument for common descent, no more, no less. The evidence for common descent can only be evidence against creation if one believes the two are mutually incompatible.”
First, everyone realizes that universal common ancestry is compatible with certain theories of divine creation (e.g., theistic evolution). However, it is incompatible with the claim that the founding members of various groups were created separately by God. That claim is a specific case of non-universal common ancestry. So “29 Evidences for Macroevolution” is an argument against creation in that sense.
Second, if evidence is compatible with separate creation by God (non-universal common ancestry), it is not probative of the contrary proposition (universal common ancestry). Since one can judge nested hierarchy to be incompatible with separate creation by God only if one assumes that God would not separately create organisms in a nested hierarchy, the inference of universal common ancestry from the evidence of nested hierarchy contains a latent theological assumption. Because Dr. Theobald is unaware of this, he takes great umbrage at what he perceives to be my erroneously attributing the assumption to him. His pique is unwarranted.
Think of it this way. If both scorching and painting could make a cloth brown, one could not logically infer that a cloth had been scorched solely from the fact it was brown. If one asserted that the cloth’s brown color was evidence of scorching, one would be assuming implicitly that the cloth could not have been painted. Otherwise, the assertion would be incoherent.
Dr. Theobald accuses me of being confused and not understanding the difference between artificial and genuine nested hierarchies because I wrote: “Dr. Theobald’s claim that ‘specially designed objects like buildings, furniture, cars, etc.’ cannot be classified in a nested hierarchy requires elaboration. In terms of mere classification, it is incorrect. Buildings and vehicles have both been used as examples of nesting.” The irony is that he is accusing me of not appreciating the very point I was making.
The reason I said his statement that objects like buildings, furniture, and cars cannot be classified in a nested hierarchy required elaboration was that, taken at face value, the statement appears to exclude the possibility that such specially designed objects could be classified artificially in a nested hierarchy. Thus I wrote that “[i]n terms of mere classification,” the statement was incorrect. To back up the claim that such specially designed objects can indeed be classified in a nested hierarchy (regardless of whether they possess genuine hierarchical traits), I pointed out that they are often used as examples of nesting.
It is in that context that I quoted Ridley. The point was that “[a]ny set of objects, whether or not they originated in an evolutionary process, can be classified hierarchically” (emphasis supplied), not that all sets of objects possess bona fide hierarchical traits. I omitted Ridley’s statement that life exhibits a genuine hierarchy because it was irrelevant to my point. So Dr. Theobald has quoted me out of context in accusing me of quoting out of context! He then builds on his confusion in suggesting that I intentionally sought to mislead people (“Camp carefully and quite misleadingly omits the very next sentence”).
The confusion continues as Dr. Theobald asserts that the basis for distinguishing artificial and genuine hierarchies became more rigorous six years after Ridley’s book was published. For that reason, he says that my quoting Ridley is on a par with quoting Lord Kelvin to argue against the existence of x-rays. But since I was not quoting Ridley to deny there is a difference between artificial and genuine hierarchies but only to support my contention that specially designed objects can be classified in a nested hierarchy, the analogy is inapposite.
Predicition 3: Convergence of Independent Phylogenies
It is claimed here that phylogenies constructed from comparisons of certain biological molecules are evidence for the truth of universal common ancestry because they fulfill the falsifiable prediction of the hypothesis of common ancestry that molecular phylogenies will “converge” on the standard morphological phylogeny (Figure 1). As I showed in the critique, it is not a falsifiable prediction of universal common ancestry that molecular phylogenies will “converge” on the standard phylogenetic tree.
I provided abundant evidence of incongruities between morphological and molecular phylogenies. Indeed, paleontologist Michael Benton wrote in 1998:
Many hundreds of phylogenies of mammals have been published, some based on morphological data and others based on molecular data (proteins, nucleic acids), and yet there is no evidence that these hypotheses of relationship are converging on a single viewpoint. Indeed, for some problems, such as the relationships of the orders of placentals, the reverse seems to be the case: with more work, and the introduction of new data, the variety of postulated phylogenies increases. (Michael J. Benton, “Molecular and morphological phylogenies of mammals: Congruence with Stratigraphic Data,” Molecular Phylogenetics and Evolution 9 [no. 3, June]: 398.)These incongruities are not an artifact of coarse measurement; they are data. Yet, none of them is deemed to have violated the “prediction” (and thus to have falsified the hypothesis) because various processes can be invoked to explain them away. Recall the comment of biochemists Schwabe and Warr:
We believe that it is possible to draw up a list of basic rules that underlie existing molecular evolutionary models:
- All theories are monophyletic, meaning that they all start with the Urgene and the Urzelle which have given rise to all proteins and all species, respectively.
- Complexity evolves mainly through duplications and mutations in structural and control genes.
- Genes can mutate or remain stable, migrate laterally from species to species, spread through a population by mechanisms whose operation is not fully understood, evolve coordinately, splice, stay silent, and exist as pseudogenes.
- Ad hoc arguments can be invented (such as insect vectors or viruses) that can transport a gene into places where no monophyletic logic could otherwise explain its presence.
This liberal spread of rules, each of which can be observed in use by scientists, does not just sound facetious but also, in our opinion, robs monophyletic evolution of its vulnerability to disproof, and thereby its entitlement to the status of a scientific theory.
The absolute, explicit and implicit, adherence to all the monophyletic principle and consequently the decision to interpret all observations in the light of this principle is the major cause of incongruities as well as for the invention of all the genetic sidestepping rules cited above. (Schwabe and Warr, 467.)
The bare hypothesis of universal common ancestry places no constraint on the operation of these processes. It therefore makes no falsifiable prediction that molecular phylogenies will converge on the standard morphological phylogeny. So, contrary to Dr. Theobald’s assertion, it is not that I believe the prediction has been falsified. Rather, I believe the claim of falsifiability is an illusion.
Dr. Theobald misses the point in arguing that even the most incongruent phylogenies match to an extraordinary degree. Since his evidence is the alleged fulfillment of a falsifiable prediction, the issue is not the degree to which phylogenies match but the degree to which the bare hypothesis of common ancestry demands that they match. Without some constraint on the operation of processes that work against congruity, which constraint the hypothesis does not provide, nonmatching phylogenies are compatible with the hypothesis. There is no falsifiable prediction of congruity.
Dr. Theobald next claims that I contradicted myself in my “eagerness to ‘disprove’ common descent.” In the first place, I was not attempting to disprove common descent. Rather, I was critiquing Dr. Theobald’s claim to have proved common descent. He assumed the burden of proof in his article and cannot slough it onto me.
Secondly, there is no contradiction in saying that inconsistent molecular and morphological phylogenies are discordant data and saying that such inconsistencies can be accommodated by ad hoc adjustments. Dr. Theobald apparently believes that no phylogenies could be considered “discordant” if all phylogenies could be accommodated, but that is simply not true. Inconsistent phylogenies can be considered discordant where certain assumptions about evolutionary mechanisms have been added to the hypothesis of universal common ancestry (i.e., where certain constraints on the processes that work against congruity are assumed). Since the bare hypothesis of universal common ancestry imposes no constraints on processes that work against phylogenetic congruity, when inconsistent phylogenies conflict with assumed constraints, the hypothesis can be preserved simply by changing the assumptions. That is precisely what is done, as Schwabe and Warr explain.
For making the obvious point that assumptions are adjusted to accommodate discordant data, Dr. Theobald falsely accuses me of slandering biologists with the charge that they “unethically manipulate their data to result in a predetermined outcome” (emphasis supplied). Apparently Dr. Theobald does not understand the difference between data and the assumptions under which data are interpreted. Did anyone accuse Schwabe and Warr of slander for saying that “Ad hoc arguments can be invented” to explain inconsistent molecular phylogenies in a way consistent with universal common ancestry or for saying that the ability to invoke such arguments robs universal common ancestry of its vulnerability to disproof?
Dr. Theobald’s challenge to construct a molecular phylogeny to his specification (that places chimps closest to fish, humans closest to birds, cows closest to insects, and bacteria closest to marsupials) misses the point. The point is that his specified molecular phylogeny would be compatible with the bare hypothesis of universal common ancestry. That hypothesis says nothing about when and where certain processes that affect the divergence of biological molecules will operate. Thus, it leaves one free to assume that those processes operate whenever and wherever is necessary to produce the specified phylogeny. Dr. Theobald again is confusing what the data are with what the hypothesis demands that they be, which is a crucial error for one claiming as evidence the fulfillment of a falsifiable prediction.
In addition to the fact the hypothesis of universal common ancestry does not predict that molecular phylogenies will match the standard morphological phylogeny, I pointed out that, even if the standard phylogeny was matched by multiple molecular phylogenies, it would not prove that the groups in question descended from a common ancestor. (As I noted, to have relevance to Dr. Theobald’s claim of universal common ancestry, the analysis would need to include all groups of living things.) The molecular differences could be linked to the morphological differences for some reason other than descent.
I cited Hunter’s example of automobiles to illustrate how phylogenies constructed from comparisons of different traits could be congruent without the subjects of the comparisons having descended from a common ancestor. Though evolutionists have used automobiles and similar things as examples of nested hierarchy, Dr. Theobald objects because he does not believe automobiles constitute a genuine nested hierarchy, which means that a comparison of their various traits would not produce congruent phylogenies. Be that as it may, the point I was attempting to illustrate cannot be denied. Common descent is not essential for nested hierarchy and therefore is not a necessary inference from the congruence of phylogenies based on different traits.
Dr. Theobald next accuses me (again) of having insufficient knowledge of basic molecular biology and genetics because I stated “it would not be surprising from a creation perspective to find that biochemical similarities increase in relation to other similarities of the creatures being compared.” More specifically, he rejects the suggestion (quoted from biochemist Gish and biologist Brand) that differences in biochemistry may, for functional reasons, correlate with differences in physiology, which may, in turn, correlate with differences in morphology. In his opinion, molecular biology and genetics have eliminated the possibility of there being a functional reason for biological molecules to correlate with physiology, and thus the correlation that exists between biochemistry and morphology must be the result of common descent.
As proof that molecular biology and genetics have eliminated the possibility of there being a functional reason for biological molecules to correlate with physiology, Dr. Theobald offers the fact that cytochrome c (and other ubiquitous proteins) from a variety of species works “just fine” in yeast that lack a native cytochrome c gene. But even if “just fine” means “as well as the native variety,”[5] this evidence is not dispositive of the issue. The fact human cytochrome c (or some other human protein) works “just fine” in yeast does not prove that it is not better suited for humans than for yeast. For that, one would need to show that yeast cytochrome c works in humans as well as human cytochrome c and that it does so throughout all phases of life from conception on.
If that could be established, it would still leave open the possibility that human cytochrome c had been designed originally to perform functions in humans beyond the bare “common function.” If those additional functions were somehow lost, perhaps in the Fall, leaving only the common function, the current correlation of cytochrome c with morphology would be a remnant of its original design. Granted this is speculation, but it is relevant because the issue is whether the cytochrome c evidence cited by Dr. Theobald eliminates the possibility of a functional basis for the correlation between cytochrome c and morphology. It does not.
And, as I pointed out elsewhere, even if the current correlation of cytochrome c and morphology was unrelated to any differences in how the protein functions, there still could be reasons for the pattern other than common descent. If, for example, ReMine is correct that nested hierarchy is a crucial aspect of the Creator’s biotic message, then one would expect that nesting to be expressed at the biochemical as well as the morphological level.
So my disagreement with Dr. Theobald on this point is not because I am ignorant of the basis of his claim. After all, he relied on the same evidence in the original article. I just think he is claiming more for that evidence than is warranted.
Dr. Theobald accuses me of inserting a red herring into the discussion because I mentioned two puzzles the cytochrome c data present from a neo-Darwinian perspective. The first is that the cytochromes of all the higher organisms (yeasts, plants, insects, fish, amphibians, reptiles, birds, and mammals) exhibit an almost equal degree of sequence divergence from the cytochrome of the bacteria Rhodospirillum. In other words, the degree of divergence does not increase as one moves up the scale of evolution but remains essentially uniform. The cytochrome c of other organisms, such as yeast and the silkworm moth, likewise exhibits an essentially uniform degree of divergence from organisms as dissimilar as wheat, lamprey, tuna, bullfrog, snapping turtle, penguin, kangaroo, horse, and human.
I expressed the puzzle presented by these data in this way:
Why would the sequence divergence of cytochrome c between bacteria and horses be the same as the divergence between bacteria and insects? The presumed evolutionary lineage from the ancestral cell to a modern bacterium differs radically from the presumed evolutionary lineage from the ancestral cell to a modern horse, both of which differ radically from the presumed evolutionary lineage from the ancestral cell to a modern insect. How could a uniform rate of divergence have been maintained through such radically different pathways? According to Michael Denton, a molecular biology researcher, “At present, there is no consensus as to how this curious phenomenon can be explained.” (Denton 1998, 291.)According to Dr. Theobald, this is a red herring because “[c]ommon descent states nothing specifically about evolutionary rates, whether they must be fast, slow, variable, or constant, and the most commonly used phylogenetic methods make no rate assumptions.” I agree that the bare hypothesis of common descent says nothing about the process by which proteins diversify, but Dr. Theobald, in contradiction of his stated purpose, went beyond that hypothesis in appealing to the differences in proteins as evidence of common descent. In doing so, he necessarily made some assumptions about the process by which proteins diversify (otherwise, no inference could be drawn from a pattern of diversity). So facts about protein diversification that are puzzling in terms of standard evolutionary thinking are indeed relevant.
Dr. Theobald asserts that the uniform degree of sequence divergence is readily explained by “neutral” evolution, but it is unclear how the notion of selectively neutral regions translates into a constant rate of mutation. If, as he acknowledges, errors in the DNA replication machinery are a factor in the mutation rate, then the degree of divergence in neutral regions should not be the same in lineages having radically different generational times. In other words, there should be more mutations in organisms with greater numbers of generations per year. As Denton says:
Explanations of uniform rates of evolution in protein genes in terms of genetic drift of neutral mutations fare no better. The rate of genetic drift in a population is determined by the mutation rate. This is not controversial. Although mutation rates for many organisms are somewhat similar per generation time—10-6/gene/generation—the problem is that generation times are vastly different, so that the rate of mutation per year in, say, yeast, may be 100,000 times greater than in a tree or a mammal such as man or elephant, organisms which have long generational times. (Denton 1998, 291-292.)Lest one get the impression that Denton is alone in seeing this as a problem, Dr. Larry Leamer of the University of North Carolina at Charlotte stated the following about the fact proteins appear to have evolved at a constant rate (http://www.bioweb.uncc.edu/faculty/leamy/evolution/neutsel.htm):
Kimura thought selection would produce spurts in the rate of evolution, and thus the constant rate of protein evolution (implying a molecular clock) seems to support neutralists. But protein molecular clock runs on absolute time, not generational time, and this is a problem for neutralists since there should be more mutations in organisms with greater numbers of generations per year (emphasis supplied).This is not to say that neutralists cannot generate hypotheses to account for the uniformity, but the uniformity is not a necessary or obvious consequence of there being neutral regions in genes. And as Denton noted, “At present there is no consensus as to how this curious phenomenon can be explained.” (Denton 1998, 291.)[6]
I pointed out that the notion that the rates of divergence remain uniform regardless of evolutionary pathway does not fit all of the cytochrome c data. I wrote:
For example, referring to Dr. Theobald’s Figure 1 (reproduced above), lampreys, carp, and bullfrogs allegedly shared a common ancestor above the node labeled “vertebra.” Since that time, the branch leading to carp and bullfrogs evolved independently of the branch leading to lampreys. If the rates of cytochrome c divergence remain uniform regardless of evolutionary pathway, then the degree of sequence variance between the cytochrome c of lampreys and carp would be essentially the same as the degree of variance between the cytochrome c of lampreys and bullfrogs. That is not the case. The variance between the cytochrome c of lampreys and carp is 12%, whereas the variance between lampreys and bullfrogs is 20%. (See matrix in Davis and Kenyon, 37.)In response, Dr. Theobald first says that “[t]hese results are not unexpected if genetics is fundamentally probabilistic instead of deterministic” (emphasis supplied). In other words, evolution expects uniform divergencies of protein sequences, but it also expects nonuniform divergencies if and when they arise. It is an amorphous theory indeed.
After stating that a nonuniform divergence between lampreys, carp, and bullfrogs would not be unexpected, Dr. Theobald then argues that the divergence between the three is in fact essentially uniform (which also is not unexpected). According to him, the true divergence between the cytochrome c of lampreys and carp is 19%, not the 12% I gave, and thus it is within 1% of the divergence between lampreys and frogs (rather than the 8% difference that my figures yield). I stand by the 12% figure, as it is the one provided by Dayhoff, the dean of the field, in Atlas of Protein Sequence and Structure (Silver Spring, MD: National Biomedical Research Foundation, 1972) vol. 5, Matrix 1, p. D-8.
The second puzzle the cytochrome c data present from a neo-Darwinian perspective is that the sequences of cytochrome c sometimes differ inversely to the presumed evolutionary proximity of the organisms being compared. I pointed out that the cytochrome c of a rattlesnake varies in 22 places from that of a turtle but only in 14 places from that of a human and the cytochrome c of a human varies in 12 places from that of a horse but only in 10 places from that of a kangaroo.
Again, Dr. Theobald considers this insignificant because, while evolution expects molecular and morphological phylogenies to match, it also expects an unspecified number of incongruities. Even if that is so, the incongruities are noteworthy, especially given Dr. Theobald’s statement: “In spite of the odds, the exact relationships given in Figure 1 were independently determined from morphological characters and from cytochrome c molecular studies” (emphasis supplied).
Prediction 4: Possible Morphologies of
Predicted Common AncestorsDr. Theobald has a problem grasping the difference between what is a prediction of the theory of universal common ancestry (the proposition for which he is arguing) and what are expectations based on assumptions that have been added to that theory. It is self-evident that the bare hypothesis of universal common ancestry affirms only that all creatures descended from the same ancestor. It would be consistent with all phylogenies rooted in a single ancestor, and therefore it does not predict any particular phylogeny, such as the standard phylogeny. For stating this obvious fact, Dr. Theobald accuses me of misrepresenting evolutionary theory.
Dr. Theobald’s confusion is apparent in his attempt to explain why I am mistaken. He states:
[A]ll organisms, both past (e.g. fossils) and present, must conform to the true phylogeny. Since the standard phylogenetic tree is the best approximation of the true historical phylogeny, we expect that all fossilized animals should conform to the standard phylogenetic tree within the error of our scientific methods. If fossilized animals do not, then there are only two logical possibilities - either our estimation of the true phylogeny is incorrect, or there is no true phylogeny (i.e. common descent is false).He is saying that if the standard phylogeny is an accurate depiction of the evolutionary history of organisms, then all organisms must conform to that phylogeny. Of course, no one would argue with that; it is a truism. If the standard phylogeny is an accurate depiction of the evolutionary history of organisms, then all organisms would conform to it by definition (otherwise, it would not be accurate). The problem is that, since we do not know the true evolutionary history of organisms, we cannot know whether the standard phylogeny is accurate.
If an organism were found that did not conform to the standard phylogeny, it would mean that the phylogeny was somehow inaccurate.[7] The question would be the level at which it was inaccurate. My point was that the inaccuracy exposed by any nonconforming organism could be corrected by adjustments to the phylogeny at a level above the hypothesized universal common ancestor. So, contrary to Dr. Theobald’s claim, the hypothesis of universal common ancestry would not be proven false by the discovery of a nonconforming organism. The standard phylogeny simply would be shown to be in need of modification at some level.
Dr. Theobald misunderstands me to be saying that provisional hypotheses are inherently immune from falsification. This leads him to quote ReMine for the point that a lack of certainty need not render a theory untestable. The irony is that ReMine would be the first to embrace my claim that the hypothesis of universal common ancestry is too amorphous to be falsified by the discovery of an organism that does not conform to the standard phylogeny. For example, ReMine says the following about evolution (which determines phylogeny):
The central illusion of evolution lies in making a wide array of contradictory mechanisms look like a seamless whole. There is no single evolutionary mechanism -- there are countless. Evolutionary theory is a smorgasbord: a vast buffet of disjointed and conflicting mechanisms waiting to be chosen by the theorist. For any given question, the theorist invokes only those mechanisms that look most satisfying. Yet, the next question elicits a different response, with other mechanisms invoked and neglected.Evolutionary theory has no coherent structure. It is amorphous. It is malleable and can readily adjust to disparate patterns of data. Evolution accommodates data like fog accommodates landscape. In fact, evolutionary theory fails to clearly predict anything about life that is actually true. As a result this book will show that evolution is not science. (ReMine, 24.)
Dr. Theobald alleged in his article that the hypothesis of universal common ancestry would be falsified by “[a]ny finding of mammal/bird intermediates.” I argued that such a find would not falsify universal common ancestry. Rather, scientists could embrace both the mammal-bird and the hypothesis of universal common ancestry. As support for my contention, I noted that two decades ago a number of scientists did precisely that -- they accepted the conclusion that birds were most closely related to mammals and yet continued in their commitment to universal common ancestry. I wrote:
The ease with which this precise adjustment could occur was illustrated two decades ago, when “[t]he reality of the ‘mammal-bird,’ a hypothetical common ancestor of birds and mammals, [was] a contentious issue in modern systematics.” (Mike Benton, 18.) Brian Gardiner’s cladistic analysis indicated that birds were most closely related to mammals, which relationship was supported by two Cambridge scientists’ analysis of molecular data. That view was readily accepted by some, even to the point that one French paleontologist “published a restoration of the hypothetical common ancestor between birds and mammals -- a sort of warm-blooded, hairy/feathery climbing insect eater!” (Mike Benton, 18.) Branches can be rearranged, even between mammals and birds, without skipping a beat in terms of commitment to common ancestry.In the face of this example that contradicts his allegation that a mammal-bird intermediate would falsify universal common ancestry, Dr. Theobald goes on the offensive. He says, “Camp is, again, self-contradictory. How can ‘mammal-birds’ at once be contentious and also be accommodated with ‘ease’, ‘without skipping a beat’? They can’t!” Dr. Theobald is not thinking clearly.
The issue is whether the discovery of a mammal-bird intermediate would falsify universal common ancestry. The fact is that those scientists who concluded that birds were most closely related to mammals (and thus that mammal-bird intermediates existed) remained fully committed to the hypothesis of universal common ancestry. They embraced the mammal-bird link without skipping a beat in terms of commitment to common ancestry. They modified the phylogeny at another level.
The scientific dispute centered on whether mammal-bird intermediates existed (i.e., on whether Gardiner’s conclusion was valid), not on whether their existence would require rejection of universal common ancestry. The fact most scientists resisted and ultimately rejected the conclusion that birds were most closely related to mammals is irrelevant to whether the discovery of a mammal-bird intermediate would falsify universal common ancestry. It just means that most scientists did not face the question because they rejected the premise on which the question is based (that a mammal-bird intermediate existed). The relevant group is the one that accepted the existence of mammal-bird intermediates, and that group saw no conflict between a mammal-bird intermediate and universal common ancestry.
So in the context of the argument, and contrary to Dr. Theobald’s assertion, mammal-bird intermediates can at once be contentious and be accepted with ease. They can be contentious in terms of their existence and can be accepted with ease in terms of their compatibility with universal common ancestry (assuming their existence). There is no contradiction.
After pointing out the resistance that Gardiner’s theory faced, Dr. Theobald asks rhetorically, “Does this sound like biologists accepted this ‘precise adjustment’ with ‘ease’? Does this sound like these ‘Branches can be rearranged, even between mammals and birds, without skipping a beat’?” (Notice how he omits the phrase “in terms of commitment to common ancestry.”) From this, Dr. Theobald charges: “In a vain effort to make his point, Camp felt it necessary to grossly misrepresent the true status of the controversy.”
The accusation that I misrepresented the controversy is based on the false premise that I claimed Gardiner’s theory gained general acceptance in the scientific community and that it did so with ease. I claimed neither. I claimed only that those who did accept the theory had no problem reconciling it with a belief in universal common ancestry. They obviously did not think that the existence of a mammal-bird intermediate falsified universal common ancestry, and no misguided attacks on me can change that.
To preempt being accused of thinking that the discovery of a birdlike mammal would necessarily force a shift in thinking about the relationship of mammals and birds (a placing of their branches next to each other), I acknowledged the possibility that the birdlike features could be attributed to convergent evolution. (The fact birdlike features are believed by some experts to have evolved convergently in dromaeosaurids would lend support to that possibility.) Dr. Theobald says it would be essentially impossible for a mammal to evolve birdlike traits. That assertion is groundless, given the astounding examples of alleged convergent evolution, but more importantly, it would not matter to my argument if it were true. That simply would mean that the discovery of a birdlike mammal would necessarily force a shift in thinking about the relationship of mammals and birds.
As an example of a generally accepted phylogenetic adjustment (at an admittedly lower taxonomic level), I mentioned the shift in thinking that has occurred over the last thirty years regarding the alleged origin of birds. This is not debatable. For example, Lawrence Witmer, an expert on bird evolution, states, “The discovery of new fossils has been a key element in the debate [about avian ancestry], with Archaeopteryx, Euparkeria, Sphenosuchus, and Deinonychus each spawning new notions and moving the debate to a different place.” (Sankar Chatterjee, The Rise of Birds [Baltimore, MD: Johns Hopkins Press, 1997], xii.) And yet, Dr. Theobald says, “Camp feels the need to misrepresent the true situation in order to make a point.”
Here is how I summarized the background of the current debate over the alleged dinosaurian ancestry of birds in the earlier article cited in my critique (with supporting references inserted in the text). The accusation that I misrepresented the facts in claiming there has been a phylogenetic adjustment is absurd.
The idea that birds descended from dinosaurs was first suggested by Thomas Huxley in 1868 on the basis of skeletal similarities between Archaeopteryx lithographica and Compsognathus longipes, a chicken-size coelurosaur recovered from the same formation as Archaeopteryx. (Alan Feduccia, The Origin and Evolution of Birds, [New Haven, CT: Yale University Press, 1996], 28, 52.) Of course, Compsognathus itself could not qualify as an ancestor for Archaeopteryx because it was “too late in time (as a direct contemporary of Archaeopteryx) and too specialized in the reduction of the manus to two digits.” (Robert L. Carroll, Vertebrate Paleontology and Evolution [New York: W. H. Freeman, 1988], 340.) Nevertheless, Compsognathus was considered illustrative of the kind of creature from which Archaeopteryx evolved. It was believed that the features shared by the two species had been inherited from a common dinosaur ancestor that was more like Compsognathus than Archaeopteryx.A number of experts (e.g., Seely and Vogt) resisted Huxley’s theory, arguing that the similarities between Compsognathus and Archaeopteryx were probably the result of convergent evolution rather than common descent from an earlier dinosaur. (Feduccia, 55, 67.) As a result, Huxley’s views never gained general acceptance. (Kevin Padian and Luis M. Chiappe, “Bird Origins” in Philip J. Currie and Kevin Padian, eds., Encyclopedia of Dinosaurs [New York: Academic Press, 1997], 73.) In 1913 Robert Broom described Euparkeria, a small, 230-million-year old thecodont, and argued that it was the common ancestor of both theropod dinosaurs and birds. This made theropods an evolutionary side branch having nothing to do with the origin of birds. Following the publication in 1926 of Gerhard Heilmann’s classic, The Origin of Birds, the thecodont (as opposed to theropod) ancestry of birds became a matter of textbook orthodoxy for the next fifty years. (Feduccia, 55; Chatterjee, 3-4.)
The theropod theory of bird origins was revived in the mid-1970s through a series of papers by John Ostrom. He detailed a number of similarities between Archaeopteryx and theropods, focusing especially on Deinonychus antirrhopus, a lightly built, 110-million-year old dromaeosaurid that he discovered in 1964. (Padian and Chiappe, 73; Feduccia , 66.) Subsequent cladistic analysis supported and refined Ostrom’s claim by identifying dromaeosaurids as the group that shared the greatest number of derived characters with Archaeopteryx. (J. A. Gauthier, “Saurischian monophyly and the origin of birds” in Memoires of the California Academy of Sciences [1986] 8: 1-55.)
I noted in passing that the assertion that all fossilized animals conform to the standard phylogenetic tree is unprovable because one can never be sure that all fossilized animals have been discovered. Dr. Theobald naturally agrees, but he claims I contradicted myself thirty-eight pages later when discussing prediction 15 (suboptimal anatomical function). I there wrote:
The suggestion that universal common ancestry would be falsified by “the discovery of a mammal without crossed gastrointestinal and respiratory tracts, or a reptile or mammal without blindspots in its eyes” is incorrect. It is another example of taking what is known not to exist and claiming that evolution predicts it could not exist.A theory that can tolerate the creation of novel structures and accommodate the radical alteration of a reptilian respiratory system into an avian system can surely handle the segregation of an airway and the removal of a blind spot. If push came to shove, one could always argue that Mammalia and/or Vertebrata were not monophyletic. Whatever difficulties an evolutionary explanation may pose, it would be considered more reasonable than denying “the fact of evolution.”
In the one case, I made the obvious (and perhaps trivial) observation that one cannot establish with absolute certainty that all fossilized animals conform to the standard phylogeny because one can never be sure that all fossilized animals have been discovered. In the other case, I argued that universal common ancestry would not be falsified by the discovery of a mammal without crossed gastrointestinal and respiratory tracts or a reptile or mammal without blindspots in its eyes because alternative explanations exist that would be considered more reasonable than denying “the fact of evolution.”
The alleged inconsistency is in my comment, “It is another example of taking what is known not to exist and claiming that evolution predicts it could not exist.” I did not mean that such creatures are known with absolute certainty not to exist (who would think that?) but that they are known with scientific probability not to exist. My point was that there is nothing in the bare hypothesis of universal common ancestry that precludes such organisms from coming into existence. So there is no way to state prospectively that they could not exist given universal common ancestry. The claim that they could not exist is made retrospectively from the fact all mammals discovered to date exhibit crossed gastrointestinal and respiratory tracts and a certain retinal configuration. Thus, Dr. Theobald is taking what is known from investigation not to exist and claiming it as a prediction of universal common ancestry, claiming that it could not exist if universal common ancestry were true.
This is lost on Dr. Theobald. He thinks the basis of my denial that universal common ancestry predicts the nonexistence of such organisms is the claim that we already know with absolute certainty that they do not exist (in which case there is no risk of being shown wrong and thus no prediction). That is incorrect. The basis of my denial of that proposition is that the bare hypothesis of universal common ancestry includes nothing to prohibit such organisms from coming into existence. The claim that they could not exist would indeed be falsified by discovering one, but since that claim does not arise from the hypothesis of universal common ancestry, falsifying it would not falsify universal common ancestry. It merely would force a modification within the evolutionary framework.
I explained in the critique why Dr. Theobald’s assertion that all fossilized animals conform to the standard phylogenetic tree turns out to be merely a restatement of the claim of nested hierarchy that adds nothing to the case for common ancestry. In response, Dr. Theobald says “they are not the same” because one deals with present organisms and the other with past organisms. The point, however, is that it is the same argument in different dress, not that the dresses are identical.
As I explained, conformity and nonconformity to the standard phylogenetic tree are defined in the article in terms of “intermediates,” which Dr. Theobald defines as “[a] fossil or modern species that displays characters definitive of two or more different taxa” (emphasis supplied). I pointed out that, under the given definition, Dr. Theobald’s examples of dromaeosaurids and synapsids did not qualify as “intermediates,” whereas all taxa qualify as “intermediates” between themselves and the taxa in which they are shown as nested. I then wrote:
But if taxa are intermediate by virtue of being nested, the existence of intermediates is not a separate argument for common ancestry. It is the argument of nested hierarchy under a different label. And if there are no intermediates between non-nested taxa, that means only that nested hierarchy is a pattern to which there are no known exceptions. As previously explained, that result could be accommodated by the theory of common descent, but it is not evidence for it.Dr. Theobald accuses me of “splitting hairs over terminology” regarding his definition of “intermediate.” He claims that when he defined an “intermediate” as “[a] fossil or modern species that displays characters definitive of two or more different taxa” (emphasis supplied), he did not mean that it was a fossil or modern species that displays characters by which two or more species are defined. He says that by “definitive” he meant only “unequivocal.” But in that case, his definition of “intermediate” would be “[a] fossil or modern species that displays characters unequivocal of two or more different taxa.” That makes no sense. Dr. Theobald is changing his definition while at the same time accusing me of error for using the one he gave in his article.
In any event, I recognized in the critique that Dr. Theobald seemed to be defining “intermediates” contrary to his stated definition. I explained that his tacit definition did nothing to rescue his point:
In citing dromaeosaurids as reptile-bird intermediates and mammal-like reptiles as reptile-mammal intermediates, Dr. Theobald is apparently defining “intermediates” as organisms that are morphologically between alleged ancestors and descendants (rather than using the specified definition of organisms that possess the definitive traits of the two relevant taxa). But if intermediates can occur by definition only between alleged ancestors and descendants, then they can occur by definition only in conformity to the phylogenetic tree.Consider the striking similarities between some marsupials and placentals. If the consensus were that a marsupial wolf evolved into a placental wolf, then the marsupial wolf would qualify as an intermediate under the definition being considered. That is, it would be morphologically between its alleged ancestor (an earlier marsupial) and descendant (the placental wolf). But since the consensus (which is reflected in the standard phylogeny) is that marsupial wolves and placental wolves arose independently, the marsupial wolf cannot qualify as a marsupial-placental intermediate, whatever its morphology. Conformity with the standard phylogeny is guaranteed by the definition.
Dr. Theobald’s knee-jerk criticality is well illustrated in his response to my statement that dromaeosaurids “possess certain specializations, such as the stiffened tail, that make them ill suited as ancestors” of birds. He calls the statement “ridiculous.” I assume he will be contacting Dr. Philip Currie, the source of that opinion, to straighten him out. According to Currie, a leading expert on bird origins, “in some characters, such as the stiffened tail, dromaeosaurids are too specialized to have been good ancestors for birds.” (Philip J. Currie, “Dromaeosauridae” in Philip J. Currie and Kevin Padian, eds., Encyclopedia of Dinosaurs [New York: Academic Press, 1997], 194-195.)
Dr. Theobald asserted in his article that there are “no morphological gaps” in the alleged dinosaur-to-bird transition and that there is an “exquisitely complete series of fossils” for the alleged reptile-to-mammal transition. I said these assertions are debatable, to say the least, and cited two earlier articles where I tried to point out some of the limitations of those claims (“On the Alleged Dinosaurian Ancestry of Birds” and “Reappraising the Crown Jewel”).[8] For this, Dr. Theobald accuses me of grossly distorting evolutionary theory.
Dr. Theobald understandably seeks to divert the discussion away from the accuracy of his statements that there are “no morphological gaps” in the alleged dinosaur-to-bird transition and that there is an “exquisitely complete series of fossils” for the alleged reptile-to-mammal transition. Rather than defend these specific statements in light of the articles, he tries to turn the discussion into a debate about whether the articles reflect an improper definition of a transitional form. The issue here, however, is not whether certain creatures deserve the label “transitional form” but whether the transitions mentioned by Dr. Theobald are void of morphological gaps.
In his discourse on the definition of transitional forms, Dr. Theobald, in characteristic fashion, accuses me of ignorance and duplicity. I deny the charges, but I am not going to chase that rabbit. Suffice to say that I believe he caricatures and misrepresents my articles. The readers can judge for themselves.
Dr. Theobald concludes his response to the critique of this prediction by accusing me of making “a veiled attack upon the scientific method itself” because I wrote:
But even if one granted that reptiles evolved into a bird and a mammal, that would not establish that reptiles and all other organisms descended from a common ancestor, which is the proposition being argued. The difference between a bacterium and a reptile, not to mention the other organisms, is considerably greater than the difference between a reptile and a bird or a reptile and a mammal. So the fact a reptile could evolve into a bird or a mammal would not mean that a bacterium could evolve into a reptile and everything else. In fact, granting that reptiles evolved into a bird and a mammal would not even establish that all birds and all mammals descended from a reptile. That would be an assumption.According to Dr. Theobald, I am here denying the legitimacy of the principle of extrapolation and thus depriving science of its ability to make any conclusions or predictions. All I am doing is pointing out the difference between what is extrapolated or assumed and what is proved.
Proving that evolution could traverse the distance from reptile to mammal would not prove that it could traverse the greater distance from bacterium to reptile (and other creatures). One could extrapolate from the lesser to the greater, but whether that extrapolation was justified would have to be demonstrated. The same holds for Dr. Theobald’s example of the laws of physics. Earth-bound physics can be extrapolated to the solar system and universe, but that would not mean the extrapolation was justified. That would have to be demonstrated by evidence (which it was prior to the moon landing in 1969).
I pointed out that, even if one granted that reptiles evolved into a bird and a mammal, the claim that all birds and all mammals descended from a reptile would still be an assumption. In response, Dr. Theobald says, “[O]nce we have established that certain reptiles have evolved into birds and mammals, we can easily assume that all birds and mammals are descendents of reptiles” (emphasis supplied). The point is that it would be an assumption.
Finally, it should not strike Dr. Theobald as strange that I focused on the examples of reptiles, birds, and mammals. These are considered the best examples, and they are the ones he highlighted as confirmations of the prediction.
Prediction 5: Chronological Order of
Predicted Common AncestorsDr. Theobald claims it is a prediction of the bare hypothesis of universal common ancestry that fossil “intermediates” will appear in the “general chronological order” reflected in the standard phylogenetic tree. As stated above, universal common ancestry would be consistent with all phylogenies rooted in a single ancestor, and therefore it does not predict any particular phylogeny, such as the standard phylogeny. It does not even predict the existence of “intermediates” as defined by Dr. Theobald (because he defines “intermediates” in terms of nested hierarchy and nested hierarchy is not an inevitable result of universal common ancestry).
Since one cannot predict from universal common ancestry that intermediates as defined by Dr. Theobald will exist or that descent will occur as reflected in the standard phylogeny, one cannot predict from universal common ancestry that intermediates will appear as reflected in the standard phylogeny. That prediction must be rooted elsewhere than in the bare hypothesis of universal common ancestry.
In explaining why he thinks this straightforward claim constitutes “more misrepresentation of evolutionary theory,” Dr. Theobald tacitly concedes the point. He states: “The order in which organisms arose is a deduction from a phylogeny. Thus, whenever we have a well-supported phylogeny, the order in which organisms are required to have arisen is firmly predicted, based upon that phylogeny” (emphasis supplied).
In other words, the expectation that organisms will appear in a particular order is not a deduction from universal common ancestry; it arises from a phylogeny. Thus, the hypothesis of universal common ancestry would not be proven false by the discovery of a fossil “intermediate” out of the order reflected in the standard phylogeny. The phylogeny could be adjusted at another level to account for the new data.
Failing to grasp the point, Dr. Theobald accuses me of contradicting myself in the very next paragraph because I acknowledged the truism that ancestors must have existed before descendants. The fact ancestors necessarily exist before descendants is perfectly compatible with the contention that one cannot predict from universal common ancestry that intermediates will appear as reflected in the standard phylogeny.
Dr. Theobald indicated in “29 Evidences for Macroevolution” that the hypothesis of universal common ancestry would be falsified if the chronological order (not the stratigraphical positions) of dromaeosaurids and synapsids were reversed (i.e., if dromaeosaurids were in any strata older/lower than that in which synapsids first appear). I disagreed because expectations about order do not derive from, and therefore do not test, the hypothesis of universal common ancestry (the reason given above) and because dromaeosaurids appearing below synapsids could be explained by claiming that this order was an artifact of the fossil record. That is, it could be assumed that synapsids actually predated dromaeosaurids but for some reason did not appear in the fossil record until later.
As support for my contention that such a claim was possible, I pointed out that dromaeosaurids, the alleged reptile-bird intermediates, first appear in the fossil record some 25 million or 100 million years after the first fossil bird, depending on whether that is Archaeopteryx or Protoavis. It is simply assumed that dromaeosaurids lived tens of millions of years before there is any evidence of their existence. If dromaeosaurids appeared in strata older/lower than that in which synapsids first appear, one could likewise extend the range of synapsids downward past the oldest dromaeosaurid.
In response, Dr. Theobald defends the proposed 25-million-year disjunction between the first appearances of Archaeopteryx and dromaeosaurids by arguing that it is statistically insignificant. The issue, however, is not whether the claim of disjunction between Archaeopteryx and dromaeosaurids can be defended but whether a claim of disjunction could be made in the event dromaeosaurids were found below synapsids. By suggesting that disjunctions of 100 million years or more are to be expected, Dr. Theobald shows how easy it would be to explain away dromaeosaurids being found below synapsids, which was my point.
As for the disjunction between the first appearances of Archaeopteryx and dromaeosaurids, Dr. Theobald underestimates the problem. It is not simply the absence of dromaeosaurids from the Early or Mid-Jurassic that must be explained but also the absence of other theropod clades whose existence is suggested by the existence of dromaeosaurids. As Witmer noted in reference to Protoavis, a Triassic bird would mean “we should reasonably expect to find Triassic representatives of the ornithomimid, tyrannosaurid, troodontid, and dromaeosaurid clades, among others.” (Chatterjee, x.)
So the situation is quite unlike the coelacanth going undetected for 80 million years. Even experts who believe that the positions of Archaeopteryx and dromaeosaurids are an artifact of the fossil record describe it as “puzzling” and “vexing.” (Padian and Chiappe, 78; Chatterjee, x.) If Protoavis is the first fossil bird, as is believed by such esteemed paleornithologists as Evgeny Kurochkin and D. Stephen Peters, it adds over 75 million years to the problem.
The flexibility that exists regarding the order of fossils is illustrated by the fact that some who accept Protoavis as the first fossil bird also accept the theory that birds descended from theropods (e.g., paleontologist Chatterjee). In other words, they do not consider the absence of a suite of theropod clades for 100 million years sufficient to falsify the claim that dromaeosaurids were reptile-bird intermediates.
And even if dromaeosaurids were excluded as reptile-bird intermediates, that would not falsify the hypothesis of universal common ancestry. Evolutionists simply would flock to the current minority position that dromaeosaurids are a convergently evolved side branch having nothing to do with bird origins. In other words, the dominant phylogeny would be revised in the name of scientific progress.
Along these same lines, some scientists are convinced that metazoans (at least six animal phyla) originated and diversified in the deep Precambrian, more than 400 million years before their first appearance in the fossil record, and that modern orders of mammals arose deep in the Cretaceous, much earlier than suggested by the fossil evidence (e.g., Daniel Y.-C. Wang, Sudhir Kumar, and S. Blair Hedges, “Divergence time estimates for the early history of animal phyla and the origin of plants, animals and fungi,” Proc. R. Soc. Lond. B 266 [Jan. 22, 1999]: 163-171; Sudhir Kumar and S. Blair Hedges, “A molecular timescale for vertebrate evolution,” Nature 392 [1998]: 917-920]). Though these claims are controversial, they show that one can embrace major gaps and disjunctions in the fossil record without abandoning one’s commitment to evolution. That commitment remains constant; it is other pieces that get moved.
I also pointed out that, when the scope of inquiry is broadened beyond the simple and fragmentary phylogeny of Figure 1, the picture changes regarding the order of appearance of fossil “intermediates.” According to Harvard-trained paleontologist Kurt Wise:
[T]he correspondence between phylogeny and the fossil record is not as strong as it might first seem. When the order of all kingdoms, phyla and classes is compared with the most reasonable phylogenies, over 95 percent of all the lines are not consistent with the order in the fossil record. The only statistically significant exceptions are the orders of first appearances of the phyla of plants and the classes of vertebrates and arthropods. Yet these three lineages also order organismal groups from sea-dwellers to land dwellers. The land-plant phyla, for example, are in a simple sequence from plants that need standing water to survive (e.g., algae and bryophytes) to those that can survive extreme desiccation (e.g., the cacti). The vertebrate classes go from sea-dwellers (fish) to land/sea creatures (amphibians) to land creatures (reptiles/mammals), to flying creatures (birds). The arthropod classes go from sea-dwellers (e.g., trilobites, crustaceans) to land dwellers (e.g., insects). So it’s not clear that macroevolution is a truly good explanation for the order of fossil first appearances of major groups of life. Such a radical idea as a global flood, for example, which gradually overcame first the sea and then the land, actually explains the primary order of major groups in the fossil record (sea to land) better than macroevolutionary theory. (Wise, 225-226.)Dr. Theobald first notes that the paper in which Wise analyzed the relevant data was not published. That is true, but it does not alter the fact Wise performed the analysis and reached the quoted conclusion.
Dr. Theobald then gives the impression that Wise’s conclusion is contradicted by a dozen studies referenced in the “Confirmation” section of Prediction 5 of his revised article. That, however, is incorrect. None of those studies duplicated Wise’s analysis. That is, they did not compare the order of all kingdoms, phyla, and classes with their most reasonable phylogenies. Rather, they took multiple cladograms of a narrower range of taxa and compared them with the fossil record for those groups.
Moreover, the results are not as impressive as one might think from Dr. Theobald’s comments. For example, the 1999 article by Benton, Hitchin, and Wills used four different methods (Spearman rank correlation [SRC], stratigraphic consistency index [SCI], relative completeness index [RCI], and gap excess ratio [GER]) to compare 58 cladograms of echinoderms, 141 cladograms of fishes, and 176 cladograms of tetrapods with the fossil record for those groups. The authors report that, for the RCI and GER, only130 of the 375 sampled cladograms yielded values that were significantly better than random, and 58 of the cladograms yielded RCI values significantly worse than random. For the SCI, only 85 of the 375 sampled cladograms yielded values that were significantly better than random, and 60 of the cladograms yielded SCI values significantly worse than random. For the SRC (which the authors disfavor), only 145 of the 375 showed a statistically significant matching of clade order and age order.
Dr. Theobald claims (in the “Confirmation” section of Prediction 5 of his revised article) that “a high positive correlation was found [using RCI, GER, and SCI] between the standard phylogenetic tree portrayed in Figure 1 and the stratigraphic range of the same taxa, with very high statistical significance (P < 0.0001).” But he does not provide a reference for that assertion. None of the studies he cites examined the phylogenetic tree portrayed in Figure 1.
For example, the 1999 article by Wills[9], which is the only article mentioned in the sentence where the claim is made, did not compare the phylogenetic tree portrayed in Figure 1 with the stratigraphic range of those taxa. Rather, Wills applied his approach to 7 cladograms of actinopterygians, 9 cladograms of eutherians, and 4 cladograms of arthropods. And none of those cladograms showed the level of statistical significance claimed by Dr. Theobald.
In fact, only 3 of the actinopterygian cladograms showed a significant deviation of RCI and GER from random, and only 2 of them showed a significant deviation of SCI from random. None of the eutherian cladograms showed a significant deviation of RCI, GER, or SCI from random, and though the arthropod cladograms showed a significant deviation of GER from random, none of them showed a significant deviation of SCI from random.
Dr. Theobald states incorrectly that the 1992 paper in Science by Norell and Novacek found a statistically significant correlation for 17 of the 21 vertebrate taxa examined. The statistically significant correlations were for 18 of the 24 cladograms, which translates to 16 of the 21 taxa. (The five taxa that did not yield statistically significant correlations were amniotes, Squamata, hadrosaurs, higher primates, and artiodactyls.)
More importantly, however, Dr. Theobald neglects to mention that the 1994 study by Benton and Storrs, which included a larger number of vertebrate taxa (74 vs. 24 cladograms), showed a greater proportion of cladogram-stratigraphy mismatch than the two 1992 studies by Norrell and Novacek. Only 55% of the analyzed cladograms showed statistically significant correlations between cladistic rank and stratigraphic appearance, which prompted the authors to ask, “Why do so many cladograms (33 out of 74) not reveal statistically significant (P < 0.05) correlations of clade and age rank?” And of the cladograms showing no correlation, 5 were negatively correlated (which is 6.7% of the total number examined).
Conclusion
In his response to my critique of “29 Evidences for Macroevolution,” Dr. Theobald accused me of devious tactics, widespread ignorance, and a host of intellectual sins. I have explained why these self-serving accusations are unfounded. It seems Dr. Theobald was more interested in fitting me with a stereotype, in portraying me as an unworthy critic, than in dealing fairly with what I was saying. His response includes personal attacks on me that do nothing to advance the discussion. They serve only as a cover for weak arguments.
A ready case in point is his attempt to portray me as deceitful for writing that “I once shared that [evolutionary] opinion of history, but having shifted my point of view, I find that the same evidence points to something entirely different.” He suggests that I am here claiming that it was the evidence of nature that brought me to my conviction that the founding members of various groups of organisms were created separately and miraculously by God. He says “[t]here is good reason to be skeptical of the claim that Camp was led to this conclusion by the ‘evidence of nature,’” that reason being that I have elsewhere declared my commitment to the authority and inerrancy of Scripture.
I trust the objective reader will recognize that I was playing off the immediately preceding Sherlock Holmes quote:
“Circumstantial evidence is a very tricky thing,” answered Holmes thoughtfully; “it may seem to point very straight to one thing, but if you shift your point of view a little, you may find it pointing in an equally uncompromising manner to something entirely different” . . . “There is nothing more deceptive than an obvious fact.”The evidence of nature is, of course, circumstantial evidence. I once perceived it as Dr. Theobald does, but “having shifted my point of view” in my conversion to Christ, which included my acceptance of Scripture as the word of God, I now perceive it as pointing to separate creation by God. I never said I was led to my current conviction by the evidence of nature, only that I now view the evidence from the vantage of that conviction.
Dr. Theobald purports to have demonstrated the truth of a proposition that I believe is false. In my critique, I explained why his evidence is insufficient to prove his claim. I did not respond to any of his arguments by appealing to the authority of Scripture. Dr. Theobald seems to be suggesting that my criticisms should be discounted because they spring from a well poisoned by religious convictions. What matters is the substance of the criticisms, not the perspective from which they were generated.
Finally, Dr. Theobald claims it is “difficult to reconcile” my statement that I now find the evidence of nature pointing to separate creation by God with my admission elsewhere that it is difficult at present to harmonize some of the scientific data with a recent creation interpretation of Scripture. The conflict is imaginary. Separate creation of organisms by God is a different proposition than recent-creation by God. Moreover, one can believe that evidence points in a certain direction while recognizing the existence of unresolved issues.
Notes
[1] I am glad my critique prompted Dr. Theobald to revise his article. Of course, that revision is irrelevant to this discussion. [RETURN TO TEXT]
[2] The stated fulfillment of the prediction is that “[m]ost existing species can be organized easily in a nested hierarchical classification” (emphasis supplied). Under prediction 4 of his response to my critique, Dr. Theobald says, “The ‘nested hierarchy’ statement, given in prediction 2, is that modern organisms should conform to a nested hierarchy if common descent is true” (emphasis supplied). [RETURN TO TEXT]
[3] Given that the alleged prediction relates exclusively to existing species, the response that “in some time frame we will always be able to observe a nested hierarchy” (emphasis supplied) is quite beside the point. [RETURN TO TEXT]
[4] Dr. Theobald informed me that I here confused Lamarck’s theory of organic progression with his theory of inheritance of acquired characters. He is correct. Since the theory of organic progression involves multiple origins, the acknowledgment that it would not yield a nested hierarchy is irrelevant to the claim that nested hierarchy is evidence of universal common descent regardless of “whether Darwinism, Lamarckism, or something else is the true mechanism of evolutionary change.” I will retain the paragraph for a time so as not to be accused of hiding my error. This does not alter the fact that the bare hypothesis of universal common ancestry can accommodate a non-nested pattern. It means only that I was mistaken in thinking that Dr. Theobald had implicitly conceded the point. [RETURN TO TEXT]
[5] It may be that our present knowledge is insufficient to allow us to identify every diminution in fitness, in which case we cannot be certain that the substitute cytochrome c is functioning as well as the native variety. [RETURN TO TEXT]
[6] Dr. Theobald is wrong to claim that I “misplaced” this quote. Equal divergencies between species mean a uniform rate of evolution, and it is the phenomenon of uniform rates of evolution that Denton is discussing. He first addresses the difficulties in explaining it in selectionist terms, and then, in the material quoted from p. 291-292, addresses the difficulties in explaining it in terms of genetic drift of neutral mutations. [RETURN TO TEXT]
[7] I do not follow Dr. Theobald’s statement that there are two logical possibilities in this instance—“either our estimation of the true phylogeny is incorrect, or there is no true phylogeny (i.e. common descent is false).” First, if universal common descent were false, the standard phylogeny would be incorrect in depicting universal common descent. Since the incorrectness of the standard phylogeny and the falsity of common descent are not disjunctive, it is incorrect to say that either the phylogeny is incorrect or common descent is false. Second, since a phylogeny is the evolutionary history of an organism or group of organisms, the only way there can be “no true phylogeny” is if there has been no evolutionary history. One cannot deduce that there has been no evolutionary history from the fact an organism does not conform to the standard phylogeny, so it is incorrect to say that the conclusion of “no true phylogeny” follows logically from the evidence of a nonconforming organism. Third, common descent being false is not the same as there being no true phylogeny, so it is incorrect to identify the falsity of common descent with the absence of a true phylogeny. [RETURN TO TEXT]
[8] Contrary to Dr. Theobald’s assertion, neither these articles nor “The Overselling of Whale Evolution” (to which I made no reference in the critique) were “updated as recently as October 7, 2001.” They have not been changed substantively in years. The “file modified dates” that appear in TrueOrigin document headers include such things as formatting changes that are done as part of the website’s routine maintenance and style modifications. [RETURN TO TEXT]
[9] Dr. Theobald gets the title of the article wrong. The article in Systematic Biology 48 (1999): 559-580 is titled “Congruence Between Phylogeny and Stratigraphy: Randomization Tests and the Gap Excess Ratio,” not “The gap excess ratio, randomization tests, and the goodness of fit of trees to stratigraphy.” [RETURN TO TEXT]
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