Tuesday, August 10, 2010

Morphology vs. Genetics vs. Evolution

Peter Pike made an interesting argument in the comment box of my previous post (link to post). The argument runs along these lines:

1) Evolutionism claims that common descent can be demonstrated via clading, where clading is broadly defined as grouping individuals in a family tree based on genetic similarity.

2) Clading is great for things like paternity testing.

3) Clading, however, is not great for predicting morphology. The Orangutan is morpholigically the most similar living animal to man, but is not genetically the most similar to man.

4) Virtually all that palentology can provide with respect to most specimens is bone morphology.

The conclusion: palentology does not support (whether or not it rebuts) the contemporary argument of evolutionism. Obviously, a good bit of the weight of the argument hangs on (3). I'm sure the typical response would be to argue that morphology is used because that's all we have. The conclusion, however, still stands. The fact that it is the best you have doesn't really mean it's enough.

- TurretinFan

23 comments:

Lockheed said...

It's fascinating to me that evolution-supporters point to similar anatomy as proof of evolution. Some of the most similar creatures (seals and sea-lions for example) are now thought to have evolved separately. Similarity only occasionally speaks to physical relationship and more often to the basic environmental need for similar physiology.

wtanksley said...

It's a minor point, TF, but when you say "clading" in your post you usually are referring to DNA clading. Cladistics is the practice of arranging things in a tree of ancestry based on clues given by their similarities and differences. Cladistics is unarguably useful in textual criticism and human genealogy.

The problem you're citing, therefore, is more accurately stated that morphological cladisitics contradicts DNA cladistics. The biggest problem with this argument is that it relies on a single point of data: an alleged contradiction between which of two primates is closer to human. It's therefore a very weak argument.

It could be strengthened by showing that some point of morphological "distance" should directly correspond to some point of genetic distance; but it's fairly widely agreed that this is impossible, and it certainly has never been done. Thus, an evolutionist can simply raise the question (even if he agrees that your #3 is true) of whether many of the morphological differences between humans and chimps are caused by relatively small genetic differences, while the ones between orangs and humans are caused by wider differences.

But even if this is rebutted, the argument remains weak, because there are so many observed cases where both genetic and morphological cladograms agree at a large scale (for example, between very different creatures or entire genera); if the small scale gets fuzzy, it may as likely be because our tools need refinement as because our theory is wrong.

Turretinfan said...

"there are so many observed cases where both genetic and morphological cladograms agree at a large scale (for example, between very different creatures or entire genera)"

Do you mean that negatively, we correctly infer that a fish is genetically diverse from a bird, based on the morphology, and we are right?

If so, that hardly is useful for creating a large-scale cladogram.

Let me put it another way. In terms of the evolutionary timescales currently postulated, genetics can only be used to associate leaves with other leaves. It's only useful on the small scale - and even on the small scale we see that it follows morphology in an unpredictable manner. We can't run genetic tests on an alleged common ancestor of even such a relatively "recent" animal as the alleged common ancestor of a pig and a horse - or even the alleged common ancestor of the chimp and the orangutan.

-TurretinFan

Peter Pike said...

(Part 1 of 2)

I figured you might appreciate some of the actual quotes. They are all taken from Schwartz, Jeffrey H. 1993. What the Bones Tell Us. New York: Henry Hold & Co.

---
It seemed that the chimpanzee alone was the most similar of the apes to humans in its molecular constitution--about 99 percent similar, to be specific. The gorilla shared a bit less of its genetic stuff with humans, and the orang a bit less again. Thus, if degree of molecular similarity reflected degree of evolutionary closeness, as was popularly assumed, then the sequence from orang, gorilla, chimp, to human represented the sequence of divergence among the large-bodied hominoids. And the date of suggested divergence among these presumed evolutionary sisters--less than 10 million years--still excluded Ramapithecus from the realm of human origins.

Needless to say, the breakup of the African ape sister group did not sit well with most primate paleontologists and systematists. If it was true that chimps were more closely related to humans than to their obvious look-alikes, gorillas, then some explanation had to be found for how the two African apes independently had evolved knuckle-walking and all of its anatomical correlates. Or, it had to be postulated that the reason chimps and gorillas were knuckle-walkers was because the last common ancestor of humans, chimps, and gorillas had been a full-fledged knuckle-walker, and that chimps and gorillas had inherited their knuckle-walking anatomies from this ancestor. If the latter explanation was true, humans would have had to have lost all traces of knuckle-walking morphology and, in this regard, would have secondarily come to look in their bones and muscles like other, non-knuckle-walking primates (p. 248).

+++++

…I [was] collecting comparative data primarily on the morphology of the palate on its tongue, or oral cavity, side. I found that, on its oral cavity side, the palate of most primates is perforated near the front (just behind the upper front teeth) by a pair of relatively large openings. Most other mammals also develop a pair of openings through the palate... These openings make it possible to pick up the skull of practically any mammal and look straight through the palate, from the oral to the nasal cavity. Humans and the great apes, however, are different.

...Instead of large apertures opening into the oral cavity, I found that gorillas typically have two clearly delineated canals emerging through the palate at its midline; these canals are separated from one another by a substantial bony wall. Chimps typically have two shallow canals emerging through the palate to the oral cavity; a raised hump of bone often separates these two shallow canals, which gives the impression of an hourglass lying on its side. Humans, as has been well illustrated in anatomy texts, have a large, single opening at the midline of the palate. And, as Peter Andrews pointed out, orangs have a single but long and slitlike opening at the midline of the palate.

It seemed to me that there was something significant--of potential evolutionary relevance--in all this. If, collectively, humans and the large-bodied apes did indeed constitute an evolutionary group--and there does seem to be convincing morphological evidence of this--then the thickening of the palate and the remodeling of the two large openings typical of mammals into canals might be another feature uniting these primates as a group. Within this group, humans and orangs seemed to be even more unique in the coalescence of the two canals into one that emerges on the oral cavity side of the palate--with the orang being even more unique than humans in compressing this single canal into a long, slitlike canal....

Even though this conclusion flew in the face of the increasingly popular human-chimp theory of relatedness, I wrote up a brief report, which was published in the journal Primates.... (p. 251-253).

Peter Pike said...

(Part 2 of 2)

+++++

If we are going to accept an exclusive human-chimp association, then we are going to have to accept the consequences that go along with it. The most profound consequence is, I think, that morphology has to be viewed as unrevealing when it comes to resolving the evolutionary relationships of organisms. Otherwise, the uniquenesses shared by chimps and gorillas, especially in their forearm anatomy, provide overwhelming evidence of their close evolutionary relationship. If we accept molecularly based phylogenies exclusively, and not as potential alternative hypotheses, we must reject fossils as being informative sources of data, because fossils are known only as preserved morphological entitites. And, thus, because fossils cannot be placed reliably in schemes of phylogenetic relationships--that can result only from a morphological analysis--they cannot be used to provide dates from which to calibrate any evolutionary clock, molecular or otherwise (p. 262, bold mine).

+++++

Remember, once the preferred theory linked humans with great apes; then it linked humans with African apes; now it links humans with chimps. And now, some molecular systematists are going the other way--questioning the human-chimp theory and favoring a human-African ape theory. On the paleontological side, specific fossils were identified as ancestors of hominids, chimps, gorillas, and orangs. Now none is considered ancestral to any hominoid. Being "right" or "wrong," especially in the evolutionary sciences, is oftentimes relevant only at a certain moment in time--depending on what ideas or intellectual frameworks are popular (p. 265).
---

Anonymous said...

Peter,

I can't make sense of the apparent dilemma about knuckle-walking. Did the dominant theory ascribe a common bipedal (non-knuckle-walking) ancestor to chimps and humans when this was written? If not, I don't understand the following:

"...and, in this regard, would have secondarily come to look in their bones and muscles like other, non-knuckle-walking primates (p. 248)."

Nor the author's apparent surprise at the idea that the common ancestor of the African apes would have been a full-fledged knuckle-walker.



o.0

natamllc said...

Wtanksley,

greetings.

I see you responded to my clarifications at the initial thread that presumably has led TF to publish this one?

I left it as it was finished by you and made no further comments to your last post there.

I am posting here to acknowledge I see the brilliance with which you write.

I am also posting to acknowledge that knowing more about natural science seems to have become slightly more prominent with people these days than knowing God? I was pointing to that that the Spirit of God was making that point through Peter in his epistle, 2 Peter chapter 1 because of Peter's use of the Greek words [ἐπίγνωσις] epignōsis and [γνῶσις] gnōsis. That shifts the focus more towards excelling in the knowledge of God over the knowledge of the sciences.

The mandate of the Church isn't so much to excel in gnosis as much as it is epignosis. Yet to be fair, now, Peter does end his epistle this way:

2Pe 3:17 You therefore, beloved, knowing this beforehand, take care that you are not carried away with the error of lawless people and lose your own stability.
2Pe 3:18 But grow in the grace and knowledge of our Lord and Savior Jesus Christ. To him be the glory both now and to the day of eternity. Amen.


cont'd

natamllc said...

Continuing:

Here is the edge of the knife I cut with and which is why my emphasis is rather on completion of it than wondering why a Christian Brother uses for the purpose of evangelism the argument of science and then have another Christian Brother come along and correct him for his use?

Here is the knife I use:

Luk 24:44 Then he said to them, "These are my words that I spoke to you while I was still with you, that everything written about me in the Law of Moses and the Prophets and the Psalms must be fulfilled."
Luk 24:45 Then he opened their minds to understand the Scriptures,
Luk 24:46 and said to them, "Thus it is written, that the Christ should suffer and on the third day rise from the dead,
Luk 24:47 and that repentance and forgiveness of sins should be proclaimed in his name to all nations, beginning from Jerusalem.
Luk 24:48 You are witnesses of these things.
Luk 24:49 And behold, I am sending the promise of my Father upon you. But stay in the city until you are clothed with power from on high."

Mat 24:14 And this gospel of the kingdom will be proclaimed throughout the whole world as a testimony to all nations, and then the end will come.


Again, I emphasize that in the other thread and the response to you I was "adding" the words more to prick the conversation towards those ends as are recorded in the Matthew and Luke citations above.

That is why I used the phrase: "Now there is no end in sight to what is and what is not." which was to underscore that the pursuit of natural science does not bring a person one bit closer to God but rather it seems to fuel the flames of debate over theistic evolution and evolution.

I believe this is the essence of what King Solomon discovered in his day that caused these Words of Scripture to be included in our Biblical Text:

Ecc 3:11 He has made everything beautiful in its time. Also, he has put eternity into man's heart, yet so that he cannot find out what God has done from the beginning to the end.


I leave off this comment now with one Scriptural justification for my motivation in responding to you there and here and it is this too to prick your imagination to find some extra time to give yourself too to this that Peter exhorts the True Believers in this world that is dying, no matter what additional scientific discovery or theories or postulations come after these fresh, new, dynamic ones become old:

2Pe 3:10 But the day of the Lord will come like a thief, and then the heavens will pass away with a roar, and the heavenly bodies will be burned up and dissolved, and the earth and the works that are done on it will be exposed.
2Pe 3:11 Since all these things are thus to be dissolved, what sort of people ought you to be in lives of holiness and godliness,
2Pe 3:12 waiting for and hastening the coming of the day of God, because of which the heavens will be set on fire and dissolved, and the heavenly bodies will melt as they burn!

Rhology said...

This is entertaining. Take the example of Henry Gee.
His book In Search of Deep Time denies that one can build a meaningful systematic history or classification of organisms' evolution over the course of time using the fossil record. And his argument makes plenty of sense.

So he retreats to cladistics, and clings to it to justify his continuing belief in Darwinian evolution. It's kind of funny - so few Christians understand how weak the fossil record argument is, so that would seem to be Darwinism's best strategy - play to widespread ignorance. Cladistics is very very weak itself, as we see here.

Of course, most Christians don't even know what "cladistics" means, so maybe that's a decent strategy anyway...

Peter Pike said...

Anonymous said:
---
I can't make sense of the apparent dilemma about knuckle-walking.
---

The problem is this. Chimps and African apes are knuckle-walkers. Gorillas and humans are not. By that basis, humans should be more closely related to gorillas than to chimps or African apes. So, if the claim is that humans are descended from the same line as chimps, then either chimps and African apes evolved knuckle-walking independently in a suspiciously fortuitous case of convergent evolution (regarding chimp and African ape), or else each came from a knuckle-walker and humans evolved non-knuckle-walking in a suspiciously fortuitious case of convergent evolution (this time, convergent with the gorilla).

Neither explaination seems satisfactory. As a result of this, and many of the other points he makes, he jettisons the belief that humans, chimps, and African apes all have the same ancestor. His own view puts humans and orangutans as the closest relatives due to morphological similarities, rather than saying humans and chimps are the closest relatives.

It should be noted that Schwartz is an evolutionist. His argument is only that the DNA evidence contradicts the morphological evidence in determining the lineage of man. I, of course, would say this is evidence against Darwinism as a whole, but Schwartz would not agree. He would maintain that evolution still happens, just not in the way that most people (based on genetic similarities) claim.

Dean Dough said...

Dear Peter,

Actually, gorillas are knuckle-walkers too. I'm assuming you mean Urangutans? Appreciate the pointer to Schwartz's work. Fascinating! His minority report has attracted a lot of criticism specifically because it pits morphology against genetics. I bet with his critics who think the two analyses will eventually be reconciled when more data becomes available.

Peter Pike said...

Dean said:
---
Actually, gorillas are knuckle-walkers too. I'm assuming you mean Urangutans?
---

Yes, sorry. I had a brain cramp there. Schwartz's claim is that humans are most closely related to "orangs" as he calls them :-D . I haven't read it yet, but I believe he explained this theory more in his book "The Red Ape."

And yes, his critics may claim that there is hope for a future resolution, but hope for a future resolution is hardly a scientific statement.

In any case, "What The Bones Tell Us" is an interesting book that doesn't primarily deal with the Human-Orangutan link, although there is a large section on it. He also deals with a lot of the morphology of Neanderthals and such. I actually bought the book for reasons completely unrealted to evolution (I was looking for some paleontology), and was pleasantly surprised to find his, as you say, "minority report" at the end.

Anonymous said...

Thanks for explaining, Peter. If I can substitute "orang" for "gorilla" and "gorilla" for "African ape" in your response, the whole thing makes a lot more sense now. (Afrian apes = chimps and gorillas, no?)

I just hadn't made the connection to orangs when Schwartz said "non-knuckle-walking primates." Forgot they're considered fist-walkers.

wtanksley said...

Sorry for my delay. Hope you're all using RSS to track this so you see comments...

I mentioned that cladograms seem to be consistent "at a large scale". TF responded:

Do you mean that negatively, we correctly infer that a fish is genetically diverse from a bird, based on the morphology, and we are right?

I mean that the genetic and morphological cladograms agree except for a blurry area at the edges. The dividing lines are in the same approximate place.

In this example, there's some question between the closest genetic approximation (chimp) and the second closest (orang); but this is a tiny uncertainty, reasonable given the complexity of the base cause (genetic conversion to phenotype).

Now, what sort of evidence WOULD rebut cladograms, with their inherent assumption of common ancestry? I don't think a single example where there were two ambiguous possibilities counts; but clearly, if there were more examples of ambiguity than there were examples of clear matching clades would fail; and also clearly, if the ambiguity were enormous so that phylums or orders kept getting redefined and mixed up between the two methods. So if there were tens of ambiguously possible genetic/phenetic "closest" human relatives, or if some of the "closest" relatives for one system were from other phyla by the other system, we would have to admit that some assumption made in constructing the cladogram had failed (and common ancestry would be the first place to look).

We can't run genetic tests on an alleged common ancestor of even such a relatively "recent" animal as the alleged common ancestor of a pig and a horse - or even the alleged common ancestor of the chimp and the orangutan.

No, we can't; but this is assumed in all of the cladogram constructions, since we normally don't have all the alleged common ancestors, even as fossils. The methodology's supposed to overcome that type of missing data -- although admittedly it's a source of error, since it's missing information.

-Wm

wtanksley said...

rather [...] than wondering why a Christian Brother uses for the purpose of evangelism the argument of science and then have another Christian Brother come along and correct him for his use?

I can see why you'd be offended; it makes sense that fighting with an evangelist would be counterproductive. In this case, though, the evangelist is not preaching the gospel, but rather is attempting to conduct science, and he's doing so by logically unsound arguments.

TF is a powerful minister for the gospel, and I'd like his arguments to not be diluted with easily refuted points.

the pursuit of natural science does not bring a person one bit closer to God but rather it seems to fuel the flames of debate

Once the community of God sought knowledge, invented the concept of science in reflection of the glory of the Law of God they saw reflected in the lesser Law God placed over the physical world. Now, they flee in the face of the slightest controversy, and you even deny that the laws of nature are worth study.

natamllc said...

Wtanksley

you might again have missed it?

You wrote: Now, they flee in the face of the slightest controversy, and you even deny that the laws of nature are worth study.

Question?

How can that be seeing I have taught in the past biology and my present ministry has a school even still? In fact, my ministry has been party to the creation of elementary to college level institutions in a number of states in this country and in several other countries around the world? In fact, our students who go through our trainings graduate among the highest S.A.T. scorers than most other private and public school systems produce in our areas!

I guess guessing isn't your best pest but at least you have not gone away in silence! At least you do not flee in the face of the slightest controversy! :)

I might suggest you might approach TF's brilliance as one on a bit of a higher plain than yours?

He might actually know a bit more than you and may have been a bit more deliberate in his scholarly approach hereon? Although I give you this. He did seem to respond to your input more favorably than mine and others! :)

Hey, I could be wrong and you could be right?

In any event I hope you did not miss my point as cited and conveyed with the mindset of King Solomon?

Ecc 3:11 He has made everything beautiful in its time. Also, he has put eternity into man's heart, yet so that he cannot find out what God has done from the beginning to the end.

And, now, I suppose there may be a link between the point King Solomon was making with this one John made, here:

Joh 21:25 Now there are also many other things that Jesus did. Were every one of them to be written, I suppose that the world itself could not contain the books that would be written.

wtanksley said...

How can that be seeing I have taught in the past biology and my present ministry has a school even still?

I truly don't know. It seems like a contradiction -- how is it that you would both teach biology, and at the same time discourage correction of errors in biology? Keep in mind that you're very explicit -- you don't argue that TF was correct; you instead argue that I shouldn't have corrected him because he's an evangelist.

I personally think TF could come up with a better argument. Perhaps you think he can't.

I might suggest you might approach TF's brilliance as one on a bit of a higher plain than yours?

No. TF is a brilliant student of the original sources of Reformation theology. He's not a specialist in biology, or even science -- and if he were, I'd ask the same questions and point out the same flaws.

He might actually know a bit more than you and may have been a bit more deliberate in his scholarly approach hereon?

No. He's reposting an item someone pointed out to him in the comments. For TF knows about these things, and to him I speak boldly. For I am persuaded that none of these things has escaped his notice, for this has not been done in a corner.

This wasn't original research; it wasn't research of any kind. It was an interesting item in an article, which unfortunately was overblown by the original author, and taken rather strongly out of context in order to "falsify" all of evolution.

There are better arguments. But they have to start by admitting the facts as they stand: and as things stand, common ancestry does an amazingly accurate job of predicting what genetic analysis will tell us based on fossil analysis. Some people, like Dr. Todd Wood, think that this not a coincidence, but rather shows a fundamental way that God made baramins to change after the flood.

In any event I hope you did not miss my point as cited and conveyed with the mindset of King Solomon?

I'm afraid I did, and still do, miss it. I have a hard time understanding the verses you're throwing in. Sorry.

-Wm

Turretinfan said...

"But they have to start by admitting the facts as they stand: and as things stand, common ancestry does an amazingly accurate job of predicting what genetic analysis will tell us based on fossil analysis."

With respect, the characterization "amazingly accurate" is really more of an opinion than a fact. Likewise, I don't think it's really accurate to say that we have compared fossil evidence and genetic evidence. As noted above, there is not much corresponding genetic evidence available for the overwhelming majority of fossil data.

I do, however, appreciate it when folks point out weaknesses in secondary sources.

- TurretinFan

wtanksley said...

With respect, the characterization "amazingly accurate" is really more of an opinion than a fact.

I think you're saying that "amazing" is an emotional reaction rather than a fact. I accept the rebuke, but you're straining out the gnat and swallowing the camel. Although I may have used the wrong units to measure accuracy, I did make the correct measurement: the important thing is that the genetic and phenotypical comparisons produce very similar cladograms, even though the way genetics translates to phenotypes is very complex.

Likewise, I don't think it's really accurate to say that we have compared fossil evidence and genetic evidence. As noted above, there is not much corresponding genetic evidence available for the overwhelming majority of fossil data.

That's a fair objection, but there's a fair answer available: even the results from _indirect_ evidence are valuable. We don't have most of the ancient genetic evidence we'd like to, but we DO have some ancient genetic evidence, and by and large when it's become available it's easily confirmed the cladogram; and when it hasn't, it's usually been due to vagueness, not due to simple contradiction. Furthermore, we use modern genetic evidence as well to reflect on ancient genomes; for example, a cladogram can be drawn which includes all modern creatures without vitamin C synthesis, and the result (IIRC) is that although a species of several very different orders lack the ability (primates, bats, guinea pigs), each of the different orders has had it disabled by a different mutation, and the disabling mutation is the same across the species of the same order. This is a very detailed result that is exactly what one would expect from common descent plus the physiological cladogram, but it's completely unexpected from a functional design point of view.

This is the sort of result that I'm talking about when I speak of accuracy. Over and over, specific results keep coming in that match up the cladograms derived from genetic evidence (for which we only have currently living specimens and very rare ancient DNA) with those derived from morphology and function (for which we have tons of evidence from current organisms, plus sparse evidence from fossils).

Don't forget: a cladogram is fundamentally based on the assumption of common descent. If the entire root assumption were false, then cladograms derived from different sources should NOT match at all.

-Wm

Turretinfan said...

"I think you're saying that "amazing" is an emotional reaction rather than a fact."

Amazing isn't something quantifiable - but that was only part of my objection.

"I accept the rebuke, but you're straining out the gnat and swallowing the camel."

Actually no ... as you will soon see.

"Although I may have used the wrong units to measure accuracy, I did make the correct measurement: the important thing is that the genetic and phenotypical comparisons produce very similar cladograms, even though the way genetics translates to phenotypes is very complex."

The question of "accuracy" is one of opinion - not of fact. Let me explain. Suppose I fire a shot that misses the intended target by a foot. Is that accurate or inaccurate? Most people would view that as pretty accurate if I'm firing a sea-to-land round over 30 miles from the cannon on a battleship. Most people would view that as pretty inaccurate if I'm shooting with a pistol at a target five feet from me.

In each case, the measurement of error is the same, but the determination of accuracy is different - partly because accuracy is a measurement of the acceptability of the error, and how acceptable the error is turns out to be a matter of opinion.

Does that make sense?

Taking the Vitamin C synthesis issue as an example - finding Vitamin C synthesis in several unrelated lines is something that is inconsistent with common descent. Subsequently finding that the synthesis is produced by apparently unrelated genomic mechanisms makes this less of a clear defeat for common descent.

Of course, the fact that all bats who synthesize Vitamin C do it the same way is not particularly strong evidence for common descent (unless the fact that different mammals do it different ways is evidence against common descent).

You can't have your cake and eat it too on the evidence.

"Don't forget: a cladogram is fundamentally based on the assumption of common descent. If the entire root assumption were false, then cladograms derived from different sources should NOT match at all."

Many living animals share common descent with one another, even according to the most rigid Creationists. For example, all the giraffes descend from a small group of giraffes that were on the ark - and ultimately all living creatures are descendants of animals that were created by God.

And, of course, since the cladogram was developed based on morphology and genetics influence morphology, we're not surprised that a genetic clading and morphological clading have some similarities.

- TurretinFan

wtanksley said...

The question of "accuracy" is one of opinion - not of fact.

I don't know what your definition of "accuracy" is to allow you to say that. As the original word user, I was intending the engineering/scientific/statistical definition, which makes "accuracy" NOT a matter of opinion; but I don't know _any_ definition of "accurate" which is in any way a matter of opinion.

Perhaps your definition of "opinion" doesn't match what I'm expecting. This is supported by the fact that you make "opinion" almost an antonym of "fact", where all the definitions I know about "opinion" make it a belief about a (putative) fact. (Are you a relativist? :-)

Most people would view that as pretty accurate if I'm firing a sea-to-land round over 30 miles from the cannon on a battleship. Most people would view that as pretty inaccurate if I'm shooting with a pistol at a target five feet from me.

But that's not a matter of opinion; it's a matter of FACT that you were shooting a naval gun or a pistol.

how acceptable the error is turns out to be a matter of opinion.

In engineering the acceptability of an error isn't a matter of opinion; it's a matter of life and death. In theology, is the acceptability of error any different? (No.)

But error is simply the negation of accuracy. "Acceptable error" and "acceptable accuracy" are two sides of the same coin. Therefore, the concept of "accuracy" is not semantically tied to "acceptability", contrary to your claim; it's possible to measure accuracy without considering whether it's acceptable or not (and this is important for QA, since you want your testers to run tests without hoping for a specific result).

Thus, I don't want you or me asking whether the cladistics accuracy is acceptable or not (and I shouldn't have said that it's "amazing"); we need to consider how objectively accurate the measurement is, before we decide whether it's relatively acceptable.

First, let me explain what I mean by "accuracy". There are two major ways of looking at accuracy: standardized and unstandardized. Standardized accuracy assumes that you have direct knowledge of the objective truth; accuracy is measured by how close you are to the truth. Unstandardized accuracy doesn't assume this, but does require multiple independent ways of measuring the phenomenon; accuracy is a measure, then, of how closely the given measure comes to the value measured by the other independent measures. (We can also talk about the "precision" of a measure, which is like the unstandardized accuracy but measured across multiple repetitions of the same experiment.)

(more)

wtanksley said...

(continued:)

For your shooting example, you're actually using unstandardized accuracy, since your two independent measurements are (1) the shooting; and (2) a tape measure from the bullet hole to the center of the target. Your two measurements are very independent and very precise (unless the person doing the measurement is pretending a different bullet hole belongs to you), so the unstandardized accuracy should be a good measure of the standardized accuracy.

Taking the Vitamin C synthesis issue as an example - finding Vitamin C synthesis in several unrelated lines is something that is inconsistent with common descent.

Crucial point: I didn't say WITH vitamin C synthesis; I said WITHOUT. Vitamin C is not an essential nutrient for most plants and animals; they require it for metabolism, but they produce it themselves. All orders have the essential gene; but some have it knocked out by a mutation (or group of mutations). With that in mind, please re-read my original post; note that the specific mutation that knocked out the synthesis capability is predictable based on a knowledge of morphological cladistics!

Of course, the fact that all bats who synthesize Vitamin C do it the same way is not particularly strong evidence for common descent (unless the fact that different mammals do it different ways is evidence against common descent).

To review: all bats (except one species, I couldn't find specifics) have the same mutation that knocks out their ability to synthesize C. This means that an observation of superficial morphology correctly predicted a genetic detail which is irrelevant to bat function or morphology -- even without looking at fossil evidence. (I suspect the one exception can be explained based on fossil evidence -- its ancestor probably diverged before the ancestors of the other bat species. But I couldn't find specifics, so I don't know.)

(more:)

wtanksley said...

Many living animals share common descent with one another, even according to the most rigid Creationists.

I respect that most Creationists have altered their views. I especially appreciate the work of people like Dr. Todd C Wood, in the area of baraminology; if I do come back to a young earth view it'll be because of people like him; people who rather than spending effort denying evolutionary change at any cost, instead attempt to study and explain the actual evidence with actual, positive theories. Wood says that the evidence for evolution is powerful and convincing: but he believes that the truth is otherwise, and we'll someday find a theory that explains the current evidence in terms of special creation. He's proposed some ideas, but mainly he works on baraminology, hoping that if we can know more about the original created Gen 1 "kinds" (the Hebrew word is "baramin") we can make a more educated theory about how the evidence looks the way it does.

And, of course, since the cladogram was developed based on morphology and genetics influence morphology, we're not surprised that a genetic clading and morphological clading have some similarities.

First, not all genetic patterns influence morphology; vitamin C synthesis, for example. All primates have a diet which normally provides enough vitamin C to allow survival without synthesis; but only some primates have their synthesis disabled. Thus, cladistics based on this should not need to match, or might match in surprising ways (for example, if chimps had the same mutation bats did, while humans had a different one). This is not what happens: the match is exact.

Second, once again: cladograms presume common descent. If you deny common descent, the very fact that a universal cladogram can be drawn AT ALL should be at least mildly surprising. The fact that you can independently derive two cladograms and have them largely agree, and then back-check one of them with fossil evidence, should make you seriously consider that your denial of common descent needs a bit of elaboration.

Again, I respect the general idea of young-earth creation. I think it's a simple, straightforward reading of the Bible, which as the Word of God is the only inerrant authority we have. If I thought that evolution was contradicted by the Word of God, I would join Todd Wood in his efforts rather than just cheering him on. But I don't think it is. Evolution isn't _predicted_ in the Word, but since neither modern astronomy nor modern geology is predicted there either, I'm OK with that in general.

-Wm