Are "Vestigial Organs" Valid Evidence of Evolution?
by Richard Peachey
What are "vestigial organs"?
"Vestigial" or "rudimentary" organs are biological structures that have no function. In The Descent of Man, Charles Darwin listed such human structures as wisdom teeth, the appendix, and the coccyx ("tailbone") as "rudimentary organs" (Scadding 173f.). In his earlier book, The Origin of Species, at the very beginning of the section on "rudimentary" organs, Darwin had said (418):
"Organs or parts in this strange condition, bearing the plain stamp of inutility, are extremely common, or even general, throughout nature. It would be impossible to name one of the higher animals in which some part or other is not in a rudimentary condition. In the mammals, for instance, the males possess rudimentary mammae. . . ."
Darwin and other evolutionists have interpreted such organs as evidence of evolutionary ancestry. In their view, a "useless" organ like the appendix is a tip-off to the fact that it wasn't created by an all-wise, purposeful Designer; it must be just a left-over inherited from our mammalian ancestors that did have a functioning appendix. As Darwin suggested (423), "Rudimentary organs may be compared with the letters in a word, still retained in the spelling, but become useless in the pronunciation, but which serve as a clue for its derivation."
(Some evolutionists would like to water down the definition of vestigial organs to make them structures of "reduced" function. See Jerry Bergman's discussion of this issue in Creation Ex Nihilo Technical Journal 14:95-98, 2000 <http://creation.com/images/pdfs/tj/j14_2/j14_2_95-98.pdf>.)
Problems with the argument from "vestigial organs"
1. It is not possible, theoretically, for us to prove the uselessness of a given organ. Evolutionary zoologist S. R. Scadding (University of Guelph) has stated (175f.):
"The 'vestigial organ' argument uses as a premise the assertion that the organ in question has no function. There is no way however, in which this negative assertion can be arrived at scientifically. That is, one can not prove that something does not exist (in this case a certain function), since of course if it does not exist one cannot observe it, and therefore one can say nothing about it scientifically. The best we can do is to state that despite diligent effort, no function was discovered for a given organ. However it may be that some future investigator will the discover the function. Consequently, the vestigial organ argument has as a premise, either a statement of ignorance (I couldn't identify the function), or a scientifically invalid claim (it does not have a function). Such an argument, from ignorance, or from negative results, is not valid scientifically, and has no place in observational or experimental science.
"Since it is not possible to unambiguously identify useless structures, and since the structure of the argument used is not scientifically valid, I conclude that ‘vestigial organs’ provide no special evidence for the theory of evolution."
2. Some organs, although apparently functionless, are clearly not derived from evolutionary ancestors in which the structures had a function. Recall Darwin's very first example in his Origin of Species (418, quoted above): "In the mammalia, for instance, the males possess rudimentary mammae. . . ." But did male mammary glands ever function in suckling offspring, in any of our alleged mammalian ancestors?! (For discussion of proposed examples of male lactation, see the article by Hosken and Kunz, and references given therein.) If not, then they are not "vestigial organs" in the sense we usually talk about. Concerning male nipples and other "vestiges of the reproductive structures of the opposite sex," Scadding comments (175):
"These structures . . . clearly reflect the embryonic development of a sexually dimorphic organism which begins its development in a sexually indifferent condition with structures characteristic of both sexes. They certainly do not reflect phylogenetic [evolutionary] development. No one supposes males evolved from females or vice versa."
Interestingly, Darwin himself (195) acknowledges the riskiness of calling organs "useless," when he is arguing on a different matter:
"With respect to the assumed inutility of various parts and organs, it is hardly necessary to observe that even in the higher and best-known animals many structures exist, which are so highly developed that no one doubts that they are of importance, yet their use has not been, or has only recently been, ascertained."
3. Organs exhibiting reduced function or no function provide poor evidence for a process supposed to generate organs with new functions. The existence of degenerate structures does not show that microbe-to-man evolution has taken place (Bergman and Howe 31). As Darwin notes, "The acquisition of a useless part can hardly be said to raise an organism in the natural scale" (199). Creationists can readily accept that created functions could have been lost as a consequence of the Curse in Genesis 3 (Ham and Wieland 41).
4. Functions have been discovered for most, if not all, of the allegedly "useless" structures suggested by Darwin and other evolutionists. In 1895 the German anatomist Wiedersheim compiled a list of eighty-six "vestigial" organs, plus about a hundred he considered "retrogressive" (on their way to becoming functionless) (Bergman and Howe 5). The list included organs now known to have important functions, such as the pineal gland and the pituitary. At the historic Scopes Trial (1925), an evolutionist testified:
"There are, according to Wiedersheim, no less than 180 vestigal [sic] structures in the human body, sufficient to make of a man a veritable walking museum of antiquities. Among these [is] the . . . appendix . . . . These and numerous other structures of the same sort can be reasonably interpreted as evidence that man has descended from ancestors in which these organs were functional. Man has never completely lost these characters; he continues to inherit them though he no longer has any use for them." (Ham and Wieland 41)
The evolutionist Scadding (175) suggests that
"Wiedersheim was largely in error in compiling his long list of vestigial organs. Most of them do have at least a minor function at some point in life. . . . As our knowledge has increased the list of vestigial structures has decreased. Wiedersheim could list about one hundred in humans; recent authors usually list four or five. Even the current short list of vestigial structures in humans is questionable."
• The appendix actually functions within the immune system; it is part of the Gut Associated Lymphoid Tissue system. The appendix is a highly specialized organ, a complex well-developed structure with a rich blood supply. The submucosa (tissue layer) is thickened and almost entirely occupied by lymphatic nodules and lymphocytes (Scadding 175; Ham and Wieland 41; Glover 34f.; Vines 39).
• The coccyx ("tailbone") "serves as a point of insertion for several muscles and ligaments including the gluteus maximus" (Scadding 175; cf. Vines 39).
• Wisdom teeth are useful, "especially if other molars wear down or decay" (Vines 39). Although we in our culture find that wisdom teeth often have to be removed, this may be because our modern diet is "too soft to give our teeth the exercise they need to achieve their full potential" (Vines 38).
Other "vestigial" organs are considered by Scadding, and (in more detail) by Bergman and Howe.
Bergman, Jerry, and George Howe. 1990. "Vestigial Organs" Are Fully Functional. Terre Haute, IN: Creation Research Society Books.
Darwin, Charles. 1958. Origin of Species. (reprint of 6th edition). New York: Mentor.
Glover, J. Warwick. 1988. "The Human Vermiform Appendix — a General Surgeon’s Reflections." Creation Ex Nihilo Technical Journal, Vol. 3, pp. 31-38. <http://www.answersingenesis.org/articles/tj/v3/n1/human-veriform-appendix>
Ham, Ken, and Carl Wieland. 1997. "Your appendix... it's there for a reason." Creation 20(1):41-43. <http://creation.com/your-appendix-its-there-for-a-reason>
Hosken, David J., and Thomas H. Kunz. 2009 (Mar). "But is it male lactation or not?" Trends in Ecology and Evolution 24(7):355
Scadding, S. R. 1981 (May). "Do 'Vestigial Organs' Provide Evidence for Evolution?" Evolutionary Theory 5:173-176. <http://dl.dropbox.com/u/18310184/evolutionary-theory/vol-05/Vol.5%2CNo.3%2C173-176%2C%20S.R.%20Scadding%2C%20Do%20%27vestigial%20organs%27%20provide%20evidence%20for%20evolution..pdf> Scadding's article was critiqued by B. G. Naylor (1982 [Sep]. "Vestigial Organs Are Evidence of Evolution." Evolutionary Theory 6:91-96. <http://dl.dropbox.com/u/18310184/evolutionary-theory/vol-06/Vol.6%2CNo.2%2C%20B.G.%20Naylor%2C%20Vestigial%20organs%20are%20evidence%20of%20evolution..pdf>) That critique was followed by Scadding's rejoinder (1982 [Dec]. "Vestigial Organs Do Not Provide Scientific Evidence for Evolution." Evolutionary Theory 6:171-173. <http://dl.dropbox.com/u/18310184/evolutionary-theory/vol-06/Vol.6%2CNo.3%2C%20171-173%2C%20S.R.%20Scadding%2C%20Vestigial%20organs%20do%20not%20provide%20scientific%20evidence%20for%20evolution..pdf>) See evolutionist discussion (hostile to Scadding) of these articles at <http://www.talkorigins.org/faqs/quotes/scadding.html>.
Vines, Gail. 1998 (Apr 25). "A waste of space." New Scientist 158(2131):38-39.
For Further Reading:
Lita Cosner, "Badly designed arguments—'vestigial organs' revisited." <http://creation.com/vestigial-organs-revisited>