It is not an obvious error.
@evograd is a scientist, and has spent far more time with that paper than myself. @pnelson is a scientist too, and did not cue into this. You read the paper and missed it too, right? It takes a lot of training to be able to identify errors like that (if it is an error), and also a bit of luck. The paper, as written, is very difficult to untangle. I’m not sure if the authors we merely sloppy in their writing, or (worse) sloppy in their thinking.
It is not really worth engaging these arguments. Without getting into the details, they are stretching pretty far in their analysis and it even seems some of these arguments are intuitive, but incorrect. They do not actually do any simulation or modeling to demonstrate they are correct. It is not even clear if their basic premise is correct.
A lot would have been clarified if they had run positive controls (simulations of common descent) and negative controls (simulations of some basic models of design / special creation). If their positive controls had come out positive, and the negatives negative, then in many ways the details don’t matter so much. However, they didn’t run those controls, so any loophole in their argument or reasoning is of high consequence.
I’d predict, if they had rune the right simulation controls, then:
- They would have clarified and demonstrated the precise predictions of common descent in this case.
- They would have found that some non-evolutionary models would make the same predictions (and would be indistinguishable from common descent)
- They would have found that some non-evolutionary models would make different predictions (and would be challenged/ruled-out by the data).
Honestly, it is no terribly hard to imagine models that would fit into class #2 or #3. So it seems their claims are overreaching pretty far, especially in light of how they are framed.
Yes, it does affect the probability calculations. They are based on an undemonstrated premise.
It is not a good argument as presented. There are good ways to apply parsimony. I’m regularly publishing on with that principle
https://pubs.acs.org/doi/full/10.1021/acscentsci.7b00405
However, in this case, it appears to be a strawman argument against a non-evolutionary process. The fact is that there is very strong evidence for common descent. There is no need for weak or fallacious arguments when we have strong arguments. Even then, we can imagine special creaiton scenarios (in theology, not science) that would produce the same data.
So, outside of science in theology, at best, we can only say that it looks like common descent from a scientific point of view. Perhaps God created in a non-evolutionary process that happens to look like evolution. Is that plausible? Well, science can’t really answer questions about what God would plausibly do or not do. So we are well outside science.
It is already relevant.
The conceptual error is very similar (in some ways) to the argument we discussed here: Winston Ewert: The Dependency Graph of Life. He was working off a semantic model of common descent (a tree), rather than the reality of what the theory actually predicts (somewhat accessible by simulation). This undermined his conclusions against common descent almost entirely. It is possible these two papers are well paired, as making the same sort of logical error in opposite ways.
If Ewert’s observation pans out with a better analysis (and he is far from demonstrating it so), he would have uncovered something interesting. He has not, however, actually yet engaged with the actually theory of common descent. It is not really an observation that would challenge common descent, at least not as part of the approach he described to us.