Another One For the “If You Made This Stuff Up No One Would Believe You” File

_{Barry Arrington

December 9, 2013

Intelligent Design}

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What does a “tree of life” purport to show? The obvious answer is a tree of life purports to show the pathways of common descent ASSUMING common descent occurred.

In the combox to a prior post a commenter who goes by wd400 writes:

That we can explain the data so well assuming a tree is evidence for common descent.

Wait just a second, you might say. Doesn’t a tree assume common descent rather than demonstrate it? Of course it does. wd400’s comment might just as well be re-cast as:

That we can explain the data so well assuming a tree is evidence for a tree.

We might be able to say that a tree of life diagram is consistent with common descent, if common descent were true. The diagram cannot be evidence for common descent for the simple reason that it assumes common descent to begin with.

In my last post I said this of Nick Matzke:

One wonders if his faith commitment to metaphysical naturalism renders him unable to see the circularity of his arguments, or if he does see it and just chooses to look the other way. My money is on the former. I think he is literally unable to grasp the obvious question begging that is immediately apparent to those who do not share his faith.

Here we see this same phenomenon again. I am all but certain that wd400 is perfectly sincere. He is not being intentionally provocative, intransigent or obtuse. It seems that it is almost literally impossible for him to see past his faith commitments to the circularity of his arguments.

Comments

wd400: "That we can explain the data so well . . ." Yeah, sure. There is precisely zero predictive capability in evolutionary theory.* As a result, because there is no concrete predictive capability, there can be no explanatory capability as to what actually occurred. Box hasn't even scratched the surface and he has already listed several huge holes in the alleged "explanation." Sure certain "related" organisms share similar features. Except for those features that are different. The shared features allegedly point to common ancestry, except when they don't because they are too far apart on the alleged tree for anyone to take us seriously. So we propose convergence in order to keep people from laughing at the mixed up tree. Similarities exist. Except when they don't. No rhyme or reason to any of it. No rule, or principle, or clear reason why similarities exist in one instance and not in another. Welcome to the Great Evolutionary Explanation: Stuff Happens. ----- * I'm using "evolution" here in the broad sense of the tree of life (the context of the thread). Yes, there are some areas with real math and real predictions like population genetics that evolutionary proponents like to pretend belong exclusively to "evolution," but they don't. We can study population genetics quite nicely on its own merits, thank you very much, without assuming that there is some tree of life trailing from the present back to the primordial soup.Eric Anderson_{December 9, 2013
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Querius @14:
Isn’t totally amazing how easily Darwinists can explain away 200 genes. Convergence or descent . . . heads I win; tails you lose.
Well said. The only way the fairy tale that is Darwinian evolution is able to remain prevalent in the sciences is through the force of law, by imposing it in the schools without the approval of the general population. We are dealing with fascism. This is inadmissible in a democracy.Mapou_{December 9, 2013
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More seriously, if Cetacea is thought to have descended from Pakicetidae on the strength of similarities between their inner ear, echolocation is even a stronger indicator of common descent with Chiroptera! As reported in the 4 September issue of Science
Evolutionary biologist Joe Parker, also at Queen Mary, University of London, compared the bat genetic sequences to those from more than a dozen other mammals, including the bottlenose dolphin. He focused on the 2300 genes that exist in single copies in all the bats, the dolphin, and at least five other mammals. He evaluated how similar each gene was to its counterparts in various bats and the dolphin. The analysis revealed that 200 genes had independently changed in the same ways, Parker, Rossiter and their colleagues report today in Nature.
Isn't totally amazing how easily Darwinists can explain away 200 genes. Convergence or descent . . . heads I win; tails you lose. -QQuerius_{December 9, 2013
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Let me also try to explain to wd400 et. al. w/ an analogy. Take your exact words, but apply it to wheeled vehicles. Can we, based on "morphology", arrange bikes/carts/cars/motorcyles/etc. into a "tree"? Of course we can, because we are creating a structure based on a set of criteria. Does the ability to create a tree of wheeled vehicles provide "evidence" that wheeled vehicles "evolved", as opposed to "were designed"? Obviously not. You cannot use the ability to create a tree as "evidence" - it is merely "consistent with". Almost everything else is, as well, which is what Neil's point was re Linnaeus and creation.drc466_{December 9, 2013
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Human evolution started in Africa. Can it be a coincidence that the same goes for bananas and that we share 50% - no 55%! - DNA? I would love to hear a darwinian explanation. :)Box_{December 9, 2013
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Q @ 9: LOL. :-)Barry Arrington_{December 9, 2013
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wdr400: “. . . and find the tree-shape that best fits the observed data” given the ASSUMPTION of common descent. You really don’t see the circularity after it has been pointed out to you over and over. Thank you wd400 for demonstrating how faith commitments trump logic and render the faithful blind, just as I pointed out in the OP. wdr400: “also – I’d like an answer to my question. How would you test for evidence of common descent?” You are asking the wrong question. Again, common descent is consistent with Neo-Darwinian theory. It is also consistent with certain forms of ID theory. You get me wrong. I am not arguing that common descent did not happen (though I have views on that subject). I am arguing that cladistic diagrams that assume common descent cannot at the same time be evidence for common descent, because of the obvious circularity. The right question is, how would I test for the Neo-Darwinian proposed mechanism for common descent (i.e., natural selection working on random heritable variation). I will tell you how I would test that mechanism. I would make some bold predictions that follow logically from the mechanism, and I would test those predictions. For example, I might say something like: “just in proportion as natural selection has acted on an enormous scale, so must the number of intermediate varieties, which have formerly existed, be truly enormous," and from this I would predict that not only would intermediate species be found in the fossil record, they would overwhelmingly dominate the fossil record. I would then go test the fossil record to determine if intermediate species predominate. If I found that far from predominating the fossil record, fossils that are arguably intermediate are exceedingly rare, I would conclude that the prediction from my theory had been falsified, and that would cause me to doubt whether my theory adequately accounts for the data.Barry Arrington_{December 9, 2013
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Didn't you know that bats evolved from whales? To escape predators, some whales developed fins that resulted in short flights at first. Only the very lightest whales could fly, and they were the ones that survived. Hitting trees would have been problematic but whales already had a head start on sonar. Hey this is fun! ;-) -QQuerius_{December 9, 2013
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... or maybe the fact that bats' and whales' remarkable ability, and the high-frequency hearing it depends on, are shared at a much deeper level than anyone would have anticipated -- all the way down to the molecular level.Box_{December 9, 2013
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What is so wrong about saying “That we can explain the data so well assuming a tree is evidence for a tree.”? That’s sort of how science works isn’t it? You have data, you build a model to explain it. When the model works well (and the tree does) you have evidence for that model. How would you go and find evidence for common descent if not following a similar approach?
But the evidence does not support common descent, i.e., a purely nested tree of life. It supports a non-nested hierarchy, which is what one would expect from intelligent design.Mapou_{December 9, 2013
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wd400: That we can explain the data so well assuming a tree is evidence for common descent.
Which data can we explain so well exactly? Are you referring to the fact that humans share 50% DNA with bananas? Or maybe the fact that shark and human proteins are “stunningly similar” and that sharks are closer to human than to zebrafish?Box_{December 9, 2013
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(also - I'd like an answer to my question. How would you test for evidence of common descent?)wd400_{December 9, 2013
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Nothing? Linneaus used a nested hierarchy, but not a tree based on evolutionary change among spices. Modern phylogenetic methods explicitly model evolutionary changes dow branches, and find the tree-shape that best fits the observed data. If the probability of data is higher under the assumption the species evolved in a tree-like fashion than under another assumption then you have evidence for tree-like evolution. Surely?wd400_{December 9, 2013
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wd400. Neil is right in comment 1 (though what his point is I am not exactly sure). What does that say about the tree being consistent with (as opposed to evidence for) common descent?Barry Arrington_{December 9, 2013
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Barry, What is so wrong about saying "That we can explain the data so well assuming a tree is evidence for a tree."? That's sort of how science works isn't it? You have data, you build a model to explain it. When the model works well (and the tree does) you have evidence for that model. How would you go and find evidence for common descent if not following a similar approach?wd400_{December 9, 2013
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Linneaus did a pretty good job of constructing the tree. And he is usually said to have been a creationist.Neil Rickert_{December 9, 2013
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