Dr. Hunter,
Hope your southern California weekend is going well.
You chose to analogize the theory of evolution to geocentrism. I am going to choose a different analogy that I believe to be more accurate and informative: X-ray crystallography and DNA structure.
Just as evolution predicts a statistically significant nested hierarchy structure in a taxonomy, biochemistry predicts that DNA can take on structural forms known as A-DNA and B-DNA. The test of the hypothesis is the similarity of the predicted X-ray crystallography images to the actual. And here I introduce some predicted and actual images from an article on quora.com, “How does one physically interpret the different diffraction patterns between A-DNA and B-DNA?”:
Now it would be possible to build a consistency index for the predicted vs. actual similarity. The CI could answer the question: for each pixel that is dark in the actual image, is the corresponding predicted pixel dark? Sum up the number of pixels for which the correspondence is true and divide by the number of dark pixels in the actual image. This approach would be very similar to the CI approach adopted by Klassen et al. in 1991, except that they were analyzing characters instead of pixels.
Without access to the original data, I cannot provide an exact CI for the A-DNA and B-DNA images. However, there are clearly a lot more dark pixels in the actual image than in the predicted. I would guess the CI is roughly 0.5 for A-DNA and roughly 0.25 for B-DNA, which has enormous black blobs at the top and bottom where a thin segment of dots is predicted.
The question is: should the actual data be interpreted as evidence for the predicted structures of A-DNA and B-DNA?
Answer #1 is:
No, the actual pixels are poor evidence for the theory. Certainly there is some similarity between predicted and actual. But just as you have to introduce epicycles into geocentrism to account for planetary orbits, you have to introduce extraneous factors to account for the CI values, which are far below 1.0. To the extent that you consider the theory of DNA structure to be good, it’s only because you are prefiltering the badly predicted pixels. Consequently we should consider the theory of DNA structure to be not a very good theory
Answer #2 is:
Yes, the actual pixels are powerful evidence for the theory. The probability of the null hypothesis for the actual images (null hypothesis = random placement of pixels due to no structure) is infinitesimal–something like 0.0000000005. Therefore the alternative hypothesis, A-DNA and B-DNA, should be accepted.
The actual images do contain significant noise in but we have known mechanisms to account for the noise.
It is also possible that some other, as-yet unidentified hypothesis might be even more consistent with the actual images than the A-DNA and B-DNA hypotheses. If that as-yet unidentified hypothesis survives peer review, then we can adopt it. But until that as-yet unidentified hypothesis shows up, we accept the A-DNA and B-DNA theory with a high degree of confidence.
The biochemistry community has adopted Answer #2, not Answer #1. We should do likewise for the theory of evolution and the Klassen data, as well as for the more recent, genomic-based phylogenetic studies.
Best regards,
Chris Falter