Vestigial organs are evidence for degenerative evolution only.
Some creationists concede that vestigial organs exist, others do not. Both, however, agree that vestigial organs cannot serve as evidence for evolution. Creationist Scott Huse argues:
Even if the concept of vestigial organs were valid, it still would not lend support to evolution since it implies structures on the way out, not in. Nascent organs, those under construction into a functional unit, are completely nonexistent. (Huse 1984: 107)
Huse's point is that vestigial organs would represent degeneration from a functional structure, not evolution of a new one. Creationists generally have no problem with the idea that things can become worse through evolution: they expect mutation to break things over time. The sticking point is whether something better can be built over time by evolutionary processes, and vestigial organs cannot serve as evidence for this. Or can they?
It is certainly true that the degeneration of a trait into a vestigial version cannot provide direct evidence for the evolutionary origin of the original trait. For instance, the fact that cave fish can degenerate from sighted to blind does not, of course, demonstrate that evolution can occur in the opposite direction, permitting an eyeless lineage to eventually develop vision. However, the wider evidentiary importance of vestigial traits is that they provide evidence for the thesis of common descent, and evidence for common descent is indirect evidence for precisely the kind of evolution Huse is interested in.
Let's take the human tailbone (the coccyx) as an example. Evolutionists will grant that the transition from tail to coccyx is primarily degenerative, involving mostly the loss of structure and function. But the implication of our having a coccyx is striking, because as long as we grant its vestigial nature (but doesn't it retain some function?) it provides strong evidence that we share common ancestry with creatures that have tails: indeed, it provides strong evidence that somewhere in the ancestral lineage leading to humanity, there was a species of creatures that had tails. Since this meshes so well with the evolutionary picture of the origin of humanity, it provides some amount of evidence for that picture, thereby providing some amount of evidence for the other elements in that picture, including the development of novel positive characteristics in our lineage. To be sure, vestigial traits do not show us how such characteristics evolved, but they provide some amount of evidence that they evolved.
Huse SM. 1984. The Collapse of Evolution. Grand Rapids, MI: Baker.
Last updated: 16 Mar 2009
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