Uncommon or Common Descent?

[swamidass (S. Joshua Swamidass)]

@JoeG

There is strong evidence for Common Descent? Really?

Yup, for example, look at:

Common Descent: Humans and Chimps / Mice and Rats

Okay, now to return to this thread finally. Thanks for everyone’s patience. First off, I need to emphasize that when I’ve made this argument in public, I am always pointing out that I am (1) simplifying the math to make it easy to understand, and (2) rounding numbers to make it easy to remember. However, @Agauger deserves a more careful answer to her questions. Into the Weeds I’m going to, now, enumerate several of the details that I’ve usually left out. In my view, none of these details undermine my point, or misrepresent the data. The formula D = T * R is only approximately correct, because it does not take into account mutations that (1) revert a lineage to its ancestral state (decreasing D), (2) are convergent with the other lineage (increasing D), or (3) mutate an already mutated position to a non-ancestral state (leaving D the same). It turns out that as TR increases, these effects cannot be ignored. So a more complicated formula is required when the observed D deviates f…

And this, courtesy of @glipsnort,

Common Descent: Humans and Chimps / Mice and Rats

Earlier, we looked at different parts of the genome (Y-chromosome vs. the rest), and compare their rates and divergences to test of common ancestry. That comparative work removes a great deal of uncertainty and the unknowns, and makes the results much more accurate. It is a very well controlled experiment. Very closely related to this conversation is some work that Stephen Shaffner did. His angle uses the same formula (T = MR), but focuses on different types of mutations, and the relative differences in rates. He looks at the very tight correlation between the variation among humans, and the differences between chimps/humans, and other species too. The key point about this analysis is that it does a much better job controlling for uncertainties in T and R. We know T is hard to tell from the fossil record. We know that R varies by type of mutation (we can measure this in the lab). So instead of trying to infer T, we can just see if the relative rates ® match up with the relative diffe…

That thread is being carefully considered by @aguager from DI. I’ve been putting that out there for several years (see the UD dialogue with @vjtorley). No one yet has offered an alternative explanation.

@swamidass

Common Descent is a Design Principle

Perhaps there is another principle can explain these patterns, but no one has produced one. It is not enough to say that “God could have created things this way.” I agree. I think He created us too, just this way. However, He chose to create us in a manner perfectly explained by common descent. In science, we need a better mathematical and quantitative explanation of all this data before we leave common descent.

Notice also why all the ID and anti-evolution arguments we have heard leave these facts untouched. This is a positive case for common descent. At absolute best, if they were not in mathematical error, ID and anti-evolution arguments are evidence that God inspired some proteins here and there. However, even if Doug Axe is correct (he is not), we cannot show new enzymes are needed in human evolution, so his argument has no bearing on human evolution.

That still stands @JoeG. If you want a good scientific challenge to common descent, encourage ID, YEC, and OEC scientists to understand this data and produce an alternate model. As long as no one tries explain it in a better way, we will only have Common Descent.

@swamidass

Not Against God’s Action

To be 100% clear, maybe God did act in our origins, science has not ruled it out. I affirm alongside you all that God providentially governs all things, including evolution, but I know this from Scripture, not any ID argument. From a Scriptural point of view, we might even find it warranted to affirm the de novo creation of Adam. I’ve been making that argument, so my opposition to ID is not because I oppose affirming God’s action. I just see no need for a bad argument to support something we already know.

Seeing no conflict between common descent and theology, I see no problem with this finding. Common descent is just how God created us.