Beyond Reasonable Doubt - Answering Christadelphian Answers on Common Descent

A few years ago, I referred to a fundamentalist Christadelphian website Christadelphian Answers which had made the regrettable mistake of linking the admirable goal of providing a Christadelphian apologetics site with evolution denialism. I hadn't thought of it for some time until looking at an old post on a Christadelphian forum ostensibly dedicated to evolution denialism that referenced a Christadelphian Answers article that claimed to provide a case against common descent. When I tried to look up that post, I found the link dead; evidently, Christadelphian Answers is no more. One of course must temper the sadness at a loss of a Christadelphian-specific apologetic site with the relief that another anti-evolution forum is no more.

The Internet Archive of course ensures that nothing is really lost, so it didn't take me long to find the offending article which began boldly:

Anyone familiar with evolutionary biology will of course be sadly shaking their heads at the bold assertion that "common descent is an unworkable hypothesis". Just the convergence of morphological and molecular phylogenies alone made the case for common descent, and this was recognised nearly sixty years ago as Linus Pauling and Emil Zuckerkandl who observed:

"It will be determined to what extent the phylogenetic tree, as derived from molecular data in complete independence from the results of organismal biology, coincides with the phylogenetic tree constructed on the basis of organismal biology. If the two phylogenetic trees are mostly in agreement with respect to the topology of branching, the best available single proof of the reality of macro-evolution would be furnished. Indeed, only the theory of evolution, combined with the realization that events at any supramolecular level are consistent with molecular events, could reasonably account for such a congruence between lines of evidence obtained independently, namely amino acid sequences of homologous polypeptide chains on the one hand, and the finds of organismal taxonomy and paleontology on the other hand. Besides offering an intellectual satisfaction to some, the advertising of such evidence would of course amount to beating a dead horse. Some beating of dead horses may be ethical, when here and there they display unexpected twitches that look like life." [1]

One of my main criticisms of Christadelphian anti-evolutionary arguments is that they are poorly-researched, ignoring readily-available material available at the time those arguments were written that would show these anti-evolutionary arguments to be wrong. The Christadelphian Answers article was published in 2015, two years after a fascinating paper PLoS One article "Beyond Reasonable Doubt: Evolution from DNA sequences" by W. Timothy J. White, Bojian Zhong, and David Penny which made a comprehensive case for common descent:

We demonstrate quantitatively that, as predicted by evolutionary theory, sequences of homologous proteins from different species converge as we go further and further back in time. The converse, a non-evolutionary model can be expressed as probabilities, and the test works for chloroplast, nuclear and mitochondrial sequences, as well as for sequences that diverged at different time depths. Even on our conservative test, the probability that chance could produce the observed levels of ancestral convergence for just one of the eight datasets of 51 proteins is ≈1×10⁻¹⁹ and combined over 8 datasets is ≈1×10⁻¹³². By comparison, there are about 10⁸⁰ protons in the universe, hence the probability that the sequences could have been produced by a process involving unrelated ancestral sequences is about 10⁵⁰ lower than picking, among all protons, the same proton at random twice in a row. A non-evolutionary control model shows no convergence, and only a small number of parameters are required to account for the observations. It is time that that researchers insisted that doubters put up testable alternatives to evolution. [2] (Emphasis mine)

Those odds alone should have prompted the author of that Christadelphian Answers article to reconsider the folly of writing an article boldly declaring that common descent was an "unworkable hypothesis" but given the PLoS One article nowhere features in the Christadelphian Answers article, I suspect the author wasn't even aware of it.

The PLoS One article is of course freely available, but for those wanting a commentary on it, there's a nice, accessible post on it at EvoGrad.

References

1. Zuckerkandl, E. and Pauling, L. (1965) "Evolutionary Divergence and Convergence in Proteins." in Evolving Genes and Proteins: a symposium held at the Institute of Microbiology of Rutgers, with support from the National Science Foundation. Eds Vernon Bryson and Henry J. Vogel. New York: Academic Press, 101

2. White WTJ, Zhong B, Penny D (2013) Beyond reasonable doubt: evolution from DNA sequences. PLoS ONE 8:e69924

"By One Man" - A Selective and Misleading Review of Christadelphian Thinking on Adam

When By One Man, an anti-evolutionary screed by Colin Byrnes and Matt Jamieson was released a few years ago,  I made the conscious decision to avoid commenting on it, reasoning that letting it sink into oblivion rather than give it the oxygen of publicity was by far the best option to take. Health issues also played a factor in not reviewing it as the last thing my mental health needed was to wade through yet another factually-inaccurate tendentious anti-evolution rant. In addition, given that the lack of truly new anti-evolution arguments meant that I was posting only intermittently, I simply didn't see the point in giving a frankly decaying horse yet another beating.  Ultimately, it doesn't matter how many quotations from 19th and 20the century authors you can string together, if the science undermines your fundamental premise, universal human descent from two people, then your argument is dead in the water and as tenable as defending a flat earth.