http://www.thedailybeast.com/articles/2014/06/01/the-crazy-way-creationists-try-to-explain-human-tails-without-evolution.html
Giberson writes:
"In the debate, I emphasized the problem of bad design that I outlined above, mentioning that bad design is common in nature and poses serious problems for ID. I gave some examples of bad design and showed a picture of an infant with a well-formed tail to illustrate one example."
Firstly, imperfect design does not equate to "no design" -- something William Paley emphasized -- if one finds a watch which doesn't work perfectly well or has superfluous parts, it doesn't mean that the watch is not designed.
"Nor, thirdly, would it bring any uncertainty into the argument, if there were a few parts of the watch, concerning which we could not discover or had not yet discovered in what manner they conduced to the general effect ; or even some parts, concerning which we could not ascertain whether they conduced to that effect in any manner whatever. For, as to the first branch of the case, if by the loss, or disorder, or decay of the parts in question, the movement of the watch were found in fact to be stopped, or disturbed, or retarded, no doubt would remain in our minds as to the utility or intention of these parts, although we should be unable to investigate the manner according to which, or the connection by which, the ultimate effect depended upon their action or assistance ; and the more complex the machine, the more likely is this obscurity to arise. Then, as to the second thing supposed, namely, that there were parts which might be spared without prejudice to the movement of the watch, and that we had proved this by experiment, these superfluous parts, even if we were completely assured that they were such, would not vacate the reasoning which we had instituted concerning other parts. The indication of contrivance remained, with respect to them, nearly as it was before." [1]
Well and good, but what else does our venerable critic say?
"The response was exactly what one would expect from lawyers. Rather than noting that apparent bad design was common and needed to be addressed by ID—a point I have made in several debates with creationists and ID theorists and has always been met with silence—the response focused exclusively on the particular example of the human tail, as if that is all that needs to be explained. One ID spokesperson, David Klinghoffer, claimed—falsely and absurdly—that I presented it a “proof of Darwinian evolution,” on which I was “very stuck.” (It is a piece of evidence, which is quite different than a proof.) Klinghoffer then attempted to undermine the argument from bad design by undermining the image I had used to illustrate my point. The image came from an article on Cracked.com, which Klinghoffer described as the “vestigial online presence of an old satirical magazine, now defunct, a knockoff of Mad.” But where the image came from is of zero import; Klinghoffer’s point does absolutely nothing to undermine the universally accepted and fully documented reality that human babies are occasionally born with tails. Google has more than a million hits—and countless images—for the term 'babies born with tails.'”
Ah, there we have it, gentlemen, now the number of Google hits on a particular topic is somehow relevant to the accuracy of said topic. Ancient aliens, here we come!
But seriously, Klinghoffer isn't wrong here. If I were to present the case that an alien spaceship had crash-landed in a friend's backyard and that he had photographed the alien before it died and melted into the ground, and show that photo to the public, only to have the public find that the photo was a fake, then if it doesn't show my dishonesty, it at least shows my shoddy homework. And we see that this is the case with Dr. Giberson, who goes on to say:
"Casey Luskin, also of the Discovery Institute, published several pieces on humans with tails that at least engaged the phenomena of tails, instead of the pedigree of the image I used. But rather than address the actual question on the table—how can ID account for bad design?—he focused exclusively on creating a tenuous speculation that there might be no such thing as genuine human tails."
Note the reasoning process here, keeping in mind that 1) there is a consensus in the scientific community that humans are sometimes born with real tails that are evolutionary throwbacks; 2) the gene for tails has been located in the human genome is the same one that mice use to produce their tails; and 3) the issue is not the human tail, but the problem of bad design in nature.
Well, as for the actual question on the table, ID has no problem with bad design in nature -- to use Paley's example, the fact that there are badly functioning watches doesn't negate the fact that the watch is designed. ID theorists agree that natural selection of random (i.e., undirected) mutations occurs, but say (rightly) that it merely breaks down things, i.e., destroys functionally complex specified information. Can it build functionally complex specified information? That is the *real* question. And let us look at his argument.
First, he appeals to the consensus, but this is never an arbiter of truth, so we shall ignore it. Let us agree that yes, humans may be born with true tails -- but this is not an atavism or an evolutionary regression:
"Dao and Netsky [10] reviewed 32 previous descriptions of tails published from 1859 to 1982. They distinguished true or persistent vestigial tails from other forms of caudal appendages or pseudotails. A true human tail is defined as a boneless, midline protrusion capable of spontaneousor reflex motion. The true human tail lacks vertebrae in all cases and is usually attached to the skin of the sacrococcygeal region. A pseudotail is a caudal protrusion composed of other normal and abnormal tissue. However, their classification is mainly based on histolopathological findings and is not done from an embryological standpoint. The associated embryogenesis of the human tail is first noted at the fourth week of gestation. The somites are formed, and the remaining primitive knot and streak compose a compact mass at the caudal end of the embryo that is called the tail bud or end bud. The continued uneven growth causes the tail bud to extend and curl beneath the hind gut. During the fifth and sixth weeks, the trunk ends in a conspicuous tail containing 10–12 caudal vertebrae. The distal portion lacks bone and is composed of mesodermal elements. During the seventh and eighth weeks, the vertebrated portion retracts into the soft tissue. The nonvertebrated part projects temporarily and then undergoes regression caused by phagocytosis, with the debris-laden macrophages migrating back to the body [11], and it disappears completely at the end of the eighth week. Thus, the presence of human tail can be considered a disturbance in the development of the embryo but not a regression in the evolutionary process." [2]
So much for the idea that human tails are an evolutionary throwback.
Next, as for the claim that humans and mice possess the same gene responsible for the development of tails, Giberson links to an article on the scientific journal Nature, which says:
"... it's first important to note that all humans briefly possess tails while in the uterus. Specifically, during normal development, certain fetal cells develop into a tail and then regress as a result of programmed cell death, or apoptosis. Investigators have identified a gene called Wnt-3a as a principal regulator of this process, at least in mice (Takada et al., 1994). Researchers have also discovered that humans indeed have an intact Wnt-3a gene, as well as other genes that have been shown to be involved in tail formation. Through gene regulation, we use these genes at different places and different times during development than those organisms that normally have tails at birth. Should this process of gene regulation somehow go wrong, however, the likelihood (albeit rare) exists that a person could indeed be born with a true tail."
What does the Wnt-3a gene do? Well, it has a whole gamut of functions, including positive regulation of mesodermal cell fate specification, axon guidance, extracellular matrix organization and biogenesis, positive regulation of protein binding, cell proliferation in forebrain, positive regulation of transcription and so on. [3]
So much for the claim that humans and mice use the same gene to make tails -- that gene makes many other things besides.
The last claim is what really matters: "... the issue is not the human tail, but the problem of bad design in nature." This poses no problem for the ID argument, because ID theory never claims that design is the only process acting in the living world. What it claims is that there are some features of the living world that darwinian evolution cannot explain -- irreducible complexity, and functionally complex specified information which could not have risen by natural processes that we know of, based on Dembski's design filter. It seems to me that by "bad design", what Dr. Giberson here means is that the genes for the tail persist despite there being no tail in anatomically normal humans -- for he says:
"Unfortunately, natural selection has no mechanism to eliminate useless features, but traits that become irrelevant can atrophy or get co-opted for some other task since there is no longer a disadvantage when those features show up in a weakened form."
But since we have seen that the gene responsible for the development of the tail in mice has many other functions, this argument doesn't withstand scrutiny.
Now, does the fact that a fetal tail exists, give evidence for common descent? Yes. But if common descent is true, does it mean ID is false? No. ID is fully compatible with universal common descent, and that babies may be born with true tails does not entail (pun intended) that the evolutionary process which gave rise to human beings was undirected. How would the fact that the persistence of a tail is due to an error in genetic regulation, imply that process by which this regulation originated is itself undirected? It would be like saying that because a doctor might perform a surgical procedure poorly, that procedure itself is flawed. Dr. Giberson has made the fallacy of a non-sequitur here, and has argued against a straw man of what ID theory proposes. If only he had tried to study and understand ID theory, rather than mount fallacious arguments... Alas, unlike human tails, the opponents of ID have the rather simian trait -- doubtlessly an evolutionary throwback! -- of "tossing irrelevant mud" (to use Giberson's own words) on the design argument. Very dreadful indeed.
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References:
[1] Natural Theology by William Paley, Chapter 1, 'State of the Argument'
[2] http://www.hindawi.com/journals/aorth/2011/153797/
[3] http://www.phosphosite.org/proteinAction.do?id=18401&showAllSites=true
Thanks for the contribution, Sri.
ReplyDeleteGreat article!!!