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Author
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Topic: Ontogenetic Depth and the Origin of Animals
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Paul A. Nelson
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Member # 26
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posted 10. September 2003 18:15
Charlie wrote:
quote:
As for cladistics and out-of-sequence fossils, thanks for the lesson of course, but everybody here, including Walter, was talking about the "rabbit in the Cambrian" type of out-of-sequence. Do you think cladistics would allow to simply ignore rabbits in the Cambrian?
Who knows? The point is, there's nothing in cladistic methodology forbidding the occurrence of derived character-states earlier in the stratigraphic record than more primitive character-states.
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charlie d.
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posted 10. September 2003 19:09
quote:
Nelson:
Who knows? The point is, there's nothing in cladistic methodology forbidding the occurrence of derived character-states earlier in the stratigraphic record than more primitive character-states.
Sure, for individual and/or minor traits, for which incompleteness can effectively be an issue. This is however a far cry from Walter's absurd claim: quote:
[with cladistics] the organisms in questions do not have an ancestor-descendant relationship, therefore they can occur in any fossil-sequence without refuting evolution.
Indeed, as far as I can tell, there is nothing in non-cladistic methodology that prevents that either. There's also nothing within cladistic methodology that mandates it, nor was cladistic somehow designed to specifically ignore or accomodate out of sequence fossils.
So, it boils down to Walter claiming that cladistics creates a "way out" for rabbits in the cambrian. But would it really, not just in some antievolutionist's imagination? When asked directly, even you can't get to really agree: "who knows?"
[ 10. September 2003, 19:10: Message edited by: charlie d. ]
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Pim van Meurs
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Member # 541
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posted 11. September 2003 00:05
I think it is important to recognize two issues wrt falsifiability of evolution/natural selection/common descent
1. The potential for falsification: That is potential falsifiable hypotheses can be generated which if supported would invalidate evolutionary theory/natural selection/common descent.
2. Practical falsification: For a theory which has withstood through time the countless attempts at falsification and which has been strengthened through increased knowledge and data, falsification becomes harder and harder.
It seems to me that Walter is objecting to 2.
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Cre8ionist
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Member # 140
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posted 11. September 2003 00:07
Pim, it was design theorists who consistently held and still hold the position that RM & NS are insufficient to account for life as we know it. Evolutionary science is simply catching up with what design theorists already knew long ago. You're going to need more than the simplistic Darwinian theory of RM & NS to account for the myriad of creatures you find here on this planet. What's more, you'll need to do more than simply add a couple of new tools to your evolutionary tool chest, like lateral transfers too. Example: Even if one accepts symbiotic theory (i.e., mitochondria -> eukaryote), it's potentially nothing more than a huge lateral transfer. One complete creature moves into another complete creature, with some mutually beneficial activities and linkages. Unless it could be demonstrated that new SC was created during the assimilation process there's nothing in the theory to help solve the basic problems design theorists raise.
I maintain that people like Wilder-Smith, Denton, Johnson and yes Nelson & ReMine, have held evolutionists feet to the fire, as well as keeping the debate alive and at the forefront of many scientist's thinking. Alas, I cannot quantify their influence but I suspect that it has been dramatic.
In any case, evolutionists are still going to need to account for the origin of creatures like trilobites (just as Walter said, with no response from the kool aid drinking evolutionists I might add), neither of the white rabbits usually waved, i.e., RM & NS, nor lateral transfers will suffice here. Same for turtles, bats, flying reptiles etc... I see a lot of smoke and mirrors, and a few rabbits being pulled from hats, but nothing which answers basic origin questions.................Cre8
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Rex Kerr
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Member # 632
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posted 11. September 2003 01:08
Paul Nelson wrote:
quote:
Grape Ape wrote:
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There are patterns in comparative genomics, comparative morphology, and the fossil record. These patterns are what are predicted by evolutionary theory.
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I'd take claims like this a lot more seriously if the evolutionary predictions I knew best (e.g., about the conservation of developmental pathways leading to homologous anatomical structures) weren't regularly reupholstered, and put out for sale on the sidewalk as "new research problems." For instance, when I was an undergraduate (1980-84) studying evolutionary biology, my anatomy, genetics, and ev bio instructors told me that -- on the basis of common descent -- one should expect to find the development of non-homologous organs, such as the eyes of flies and vertebrates, regulated by non-homologous genes.
I'd take Paul's lack of confidence a lot more seriously if biologists had known how development works back in 80-84. We're still pretty clueless now (although less so than before). Predictions made about any system that is at best poorly understood are likely to be wrong.
But the key question that Paul fails to ask is: does common descent hold up in areas we understand well?
To answer this question, one first has to ask: do we understand anything in biology well? A few things: transcription, translation, DNA replication, mitosis, meiosis. We certainly don't understand everything about any of these areas, but we do know enough to make very solid predictions about what common descent should produce in the absence of selection, and about what is likely to be selectable.
So we learn that mutations in non-coding non-promoter regions and synonymous mutations are hard to select for or against. And then, given how inheritance works, we notice the following.
Suppose we have three organisms, A, B, and C. We take a gene--let's call it gene 1--and figure out which pair of organisms have the most closely related gene 1 in synonymous sites. We can group these with parentheses, so our answer will be (AB)C, (AC)B, or (BC)A depending on how the answer turns out.
Now, common descent predicts that if A and B are close to each other, then A and B are equally far from C. The reason is because A and B presumably shared a common ancestor {AB} and {AB} had a long time to accumulate changes from C. Guess what you actually see the vast majority of the time when you do this?
Common descent makes another prediction. If you take another gene--gene 2, let's say--it would show the same grouping as gene 1. (It has to--genes 1 & 2 were going through the same process together, under common descent.) So if we see (A1,B1)C1 then we expect (A2,B2)C2 nearly all the time instead of 1/3 of the time as you'd expect by chance. Likewise with (A3,B3)C3, (A4,B4)C4, and so on.
Guess what you actually see?
Those are the easy tests; common descent has passed with flying colors and no other theory that has been proposed (that isn't common descent with a few bells and whistles) can account for this data.
Now that we're starting to get whole genomes sequenced, we'll soon be able to conduct a whole new set of tests, because we'll be able to tell if big chunks of genetic material appear fully formed and functional, or seem to hop across the standard cladistic trees.
If these tests fail badly, common descent is dead. There aren't any protections, because we understand the system fairly well. If the tests fail a bit, then we can start looking around to see if we've missed something, oversimplified the biology in a way that makes things less simple than we think. If we don't find anything, common descent is dead.
I volunteer to dig the grave if this comes to pass. Theories which are too wrong shouldn't be accepted even if there is nothing better to replace them. It is more honest simply to say we don't know.
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Pim van Meurs
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Member # 541
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posted 11. September 2003 01:14
Creationist: Pim, it was design theorists who consistently held and still hold the position that RM & NS are insufficient to account for life as we know it.
Actually it was Darwin himself who suggested this as well. But creationists do not just hold that RM&NS is insufficient to account for life but also other natural mechanisms.
Design theorists however have failed to provide either positive evidence to support their position nor have they provided any testable hypotheses either.
I would be interested to hear more about these basic problems, design theorists raise. Perhaps I can help resolve whether they are truely shown to be problems?
I have yet to see much evidence that science has been aware of much of the work by these people you quote, they remain mostly unknown in scientific literature, and I have seen few references to their works.
Not surprisingly becuase science deals in testing hypotheses and few have been proposed.
Creationist: I see a lot of smoke and mirrors, and a few rabbits being pulled from hats, but nothing which answers basic origin questions
From either side I may ask but origins is not so much the issue as much as evolution. Genetic and phylogenetic evidence strongly suggests common descent and evolutionary mechanisms continue to be adequate explanations for the observations. Early life may have experienced LGT which will make establishing the true root(s) of the tree somewhat complicated and perhaps unresolvable but most of the tree shows pretty strong evidence of evolution.
What is so special about the origin of trilobites btw? So far I indeed have seen a few rabbits pulled from the hats but I'd argue that they may be mostly imaginary :-)
You may not be happy with evolutionary explanations of the massive evidence supporting common descent relationships but I see no attempts to provide for better explanations of these observations. Just rejecting RM&NS hardly is helpful in building an alternative cause.
Btw what are kool aid drinking evolutionists?
Creationist: You're going to need more than the simplistic Darwinian theory of RM & NS to account for the myriad of creatures you find here on this planet.
perhaps, Darwin himself seemed to be quite aware that variation and natural selection may not have been sufficient. But LGT may just be seen as a form of bacterial sex, variation is transmitted among different species. It might be that such forms of variations may be quite 'Darwinian'.
[ 11. September 2003, 01:28: Message edited by: Pim van Meurs ]
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Paul A. Nelson
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Member # 26
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posted 11. September 2003 09:11
Rex wrote:
quote:
Now that we're starting to get whole genomes sequenced, we'll soon be able to conduct a whole new set of tests, because we'll be able to tell if big chunks of genetic material appear fully formed and functional, or seem to hop across the standard cladistic trees.
In light of this -- your views about the following?
http://www.makeashorterlink.com/?X52925ED5
In global transposon mutagenesis experiments with Mycoplasma, nearly one third of its estimated 300 essential genes were ORFans.
[ 11. September 2003, 09:11: Message edited by: Paul A. Nelson ]
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Walter ReMine
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Member # 906
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posted 11. September 2003 09:21
Odds n' Ends
quote:
".... common descent would be in a bind if we had no evidence whatsoever that HGT could occur, because then we'd have no explanations compatible with common descent for the occasional phylogenetic tree discrepancies." (charlie d., 09/09/2003)
That's an illusion. The key evolutionary mechanisms have never been experimentally demonstrated over macro-evolutionary scales. Think of the classic examples: descent with modification, "convergence," atavism (i.e. genetic throwbacks). All those were strongly embraced even by early Darwinians. These were not experimentally demonstrated over large-scales in any clear fashion, yet evolutionists firmly embraced these explanations anyway. They considered evolution a "fact" not seriously "in a bind" due to lack of experimental demonstration. It's a farce, a gross historical inaccuracy, to pretend that evolutionists were seriously restrained by the lack of experimental demonstration.
The macro-evolutionary evidences are not based on sufficient experimental demonstrations of their power. Instead, macro-evolutionary evidences are almost always pattern-based. Since evolutionary theory is a structureless smorgasbord, evolutionists generally only 'match' an observed pattern with one of their infinitude of flexible stories. The pattern becomes the prime evidence (usually the sole evidence) for the chosen explanation. I dispute the notion that evolutionists have been seriously restrained by the lack of sufficient experimental demonstration. Historically they've shown quite the opposite.
==============================
Previously I correctly listed various evolutionist explanations for "out-of-sequence" fossils. There is no dispute whatever that evolutionists use these. (Note: "Mars rocks", Leslie Orgel's theory of directed panspermia, and Hoyle's theory of gene's from space, are all examples of "It came from Space" used by modern evolutionists/non-creationists.)
Some of the explanations on that list (namely, reworking, overthrusts, and radiometric errors), can often be corroborated by independent evidence. But others on the list -- especially data-incompleteness and branching -- generally are not corroborated by independent evidence, but are invoked in a far more free-form, ad-hoc manner.
Under the "Branching, or cladogenesis" explanation, evolutionists merely claim the organisms are not on the same lineage, but instead are on separate branches, with events of cladogenesis separating them -- no ancestor-descendant relationship. The evolutionist responds to challenges like this, "The two fossils are NOT out-of-sequence, because the two organisms do NOT have an ancestor-descendant relationship. There is no lineage leading from one to the other, therefore I challenge you nasty creationists to show the two organisms have an ancestor-descendant relationship!!! I further challenge you to find a single fossil out-of-sequence with evolutionary expectations!!! See how risky evolution is! See how testable it is! You creationist fools obviously don't know how science works! You're so full of religious-thinking you can't see straight!" In one form or another, that now represents the predominant evolutionist thinking on the matter. And no, I'm not impressed by it.
quote:
"Incompleteness is a fact all historical sciences have to cope with, but it would not make rabbits in the Cambrian any more acceptable than a Cadillac buried inside an Egyptian pyramid." (charlie d., 09/09/2003)
As I said, trilobites are the "rabbits in the Cambrian", and trilobites are every bit as potent as evidence against evolution.
To use his example, trilobites are like the "Cadillac buried inside an Egyptian pyramid." But there is one difference. The Cadillac example would, if true, be powerful evidence for ancient astronauts or time-travelers -- which are versions of "It came from Space!" But earth's fossil-sequence (trilobites and the rest) provide little latitude in that direction. Indeed, earth's fossil-sequence makes various notions of "It came from Space" maximally awkward (to the extent that such a vacuous explanation can be made awkward). In other words, trilobites in the Cambrian (like many other organisms in the Cambrian Explosion!) are problematic for evolution, while simultaneously resisting "It came from Space!" This is one small example, (though there are many larger ones I could list) that are straightforward expectations of Message Theory.
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quote:
"This is the crux of the matter ... There are patterns in comparative genomics, comparative morphology, and the fossil record. These patterns are what are predicted by evolutionary theory." (Grape Ape, 09/10/2003)
I disagree. Macro-evolutionary theory is a structureless smorgasbord. It makes no predictions. Rather, the information flow is in the opposite direction. The observed patterns of life give shape to an otherwise amorphous evolutionary theory. The observed patterns are the driving force -- evolutionary theory merely adapts to them like fog adapts to landscape.
quote:
"But you guys are trying to pretend as if evolutionary theory doesn't make predictions simply because there also exist explanations for the anomalies. That's just weird." (Grape Ape, 09/10/2003)
That's not quite it. Evolutionary theory doesn't make predictions, because it is a structureless smorgasbord of every conceivable natural explanation. Evolutionists select those natural explanations that seem to fit the observed pattern. I call this 'Natural' selection! (Yes, it's a pun, but quite apt.)
quote:
"Secondly, common descent is only as good as it's ability to explain the similarities and differences between organisms. Take away its ability to explain these things (by having sequences be randomly distributed, or by getting rid of the hierarchy) and there's no need to invoke it. We would instead invoke HGT, or whatever other process, and toss common descent by the wayside." (Grape Ape, 09/10/2003)
That's a totally accurate statement of evolutionist thinking. That is, evolution is a no-lose, no-risk proposition, and is not driven by experimental demonstrations of its claims, instead it is driven by pattern. He says, if common descent could not explain the pattern then "there's no need to invoke it" so "toss common descent by the wayside" and "instead invoke HGT, or whatever other process". Modern macro-evolutionary theory is structureless and doesn't predict anything, it is merely adapted, post hoc, to fit the observed data.
Given such incredible flexibility, what would cause evolutionists to abandon common descent?
- Rabbits/trilobites in the Cambrian, (and other organisms in the Cambrian Explosion).
- The systematic absence of clear-cut lineages over large-scales. (This was a key motive force in the rise of punk ek theory, and the diminution of classical Darwinism.)
- The systematic absence of gradualism over large-scales, (as measured by what we can experimentally demonstrate today).
- The existence of a risky, scientifically testable, ID theory that explains the major patterns of life (including life's substantial hierarchical patterns, life's profound biochemical unity, the abundance of so-called "convergence," and many others).
I say evolutionists are blinded by their ability to glibly 'explain' everything they see. Given the incredible flexibility of their paradigm, it is doubtful they would 'see' anti-evolutionary evidence if it sat on them.
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Pim van Meurs writes:
quote:
"It seems to me that Walter is objecting to .... Practical falsification: For a theory which has withstood through time the countless attempts at falsification and which has been strengthened through increased knowledge and data, falsification becomes harder and harder." (Pim van Meurs, September 11, 2003)
I object to his repeated (now third attempt) to mis-present me on this matter. There is no excuse for it. See my previous posts -- notice the bold-italics there.
-- Walter ReMine
The Biotic Message
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Paul A. Nelson
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Member # 26
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posted 11. September 2003 09:29
I wrote:
quote:
Who knows? The point is, there's nothing in cladistic methodology forbidding the occurrence of derived character-states earlier in the stratigraphic record than more primitive character-states.
Charlie replied:
quote:
Indeed, as far as I can tell, there is nothing in non-cladistic methodology that prevents that either.
Not true: stratophenetic methods ["reading evolution off the fossils and stratigraphy"] are stymied by out-of-sequence distributions. Not to mention common sense, which tells one that if Grandma shows up in the fossil record after her granddaughter, our knowledge that Grandma really is grandma (the ancestral form) was not derived from fossils or stratigraphy.
Some stratigraphic discordances are quite striking (e.g., Archaeopteryx), several millions of years out of sequence.
quote:
There's also nothing within cladistic methodology that mandates it, nor was cladistic somehow designed to specifically ignore or accomodate out of sequence fossils.
I'd disagree: indeed one of the main motivators for the rise of cladistics was the failure of older methods [stratophenetic, mostly] to solve problems of phylogeny, in part because of uncooperative stratigraphy.
quote:
So, it boils down to Walter claiming that cladistics creates a "way out" for rabbits in the cambrian. But would it really, not just in some antievolutionist's imagination? When asked directly, even you can't get to really agree: "who knows?"
No -- I said "who knows?" because I took Grape Ape's scolding about armchair psychologizing to heart. "If these results showed up, you'd ignore them" is a cheap and easy way to dismiss one's conversation partner.
In any case, the fundamental logic of cladistic methods subordinates stratigraphic position to an atemporal character analysis.
[ 11. September 2003, 09:29: Message edited by: Paul A. Nelson ]
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yersinia
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Member # 324
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posted 11. September 2003 10:21
Paul writes,
quote:
In any case, the fundamental logic of cladistic methods subordinates stratigraphic position to an atemporal character analysis.
Paul, what about the fact that the branching order of phylogenies (independently derived from cladistic analysis of molecular characters) correlates well with the appearance of groups in the fossil record?
Isn't the important thing the statistical correlation, not the odd fossil a few piddling million years out of sequence (especially considering the vagaries of fossilization)? Isn't expecting 100.0000000% order a totally unrealistic strawman you are setting up?
If I document the good statistical correlation, will you concede that this is a strong point in favor of common descent?
(Same question for Remine; both Paul Nelson and Remine seem to be assuming that no such correlation exists and that this is evidence against common descent)
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Pim van Meurs
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Member # 541
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posted 11. September 2003 12:23
While Walter seems somewhat blinded by his anti-darwinian stance he yet wants to accuse scientists of being blinded, unable to make darwinian predictions, unable to make evolutionary predictions and unable to test or falsify their ideas.
As I have shown these ideas are without much merrit.
Given the massive amounts of evidence supporting such evolutionary concepts as common descent, natural selection, variation, evolutionary theory has gained a strong foothold withing scientific inquiry.
I find Remine's objections without much merrit as they fail to take into consideration the overall picture, creates strawmen 'evolutionary' positions, makes unsupported assertions and is unnecessarily vague.
Paul made an interesting comment "Some stratigraphic discordances are quite striking (e.g., Archaeopteryx), several millions of years out of sequence."
I would like to hear more about this 'discordance' but in the end as Yersinia states it "If I document the good statistical correlation, will you concede that this is a strong point in favor of common descent?"
Should we not look at the overal evidence ? Which is overwhelming in support of an ancient world in which animals show patterns of common descent
[ 11. September 2003, 12:26: Message edited by: Pim van Meurs ]
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Paul A. Nelson
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posted 11. September 2003 14:19
Yersinia wrote:
quote:
Paul, what about the fact that the branching order of phylogenies (independently derived from cladistic analysis of molecular characters) correlates well with the appearance of groups in the fossil record?
How strong is the correlation? I haven't looked at this issue in some time, but looking again at Michael Benton's papers raises interesting questions:
Michael J. Benton, Rebecca Hitchin, and Matthew Wills, "Assessing Congruence Between Cladistic and Stratigraphic Data," Systematic Biology 48 (1999):581-596.
I know Benton has published more recently on this topic, but at the moment can't remember where.
[ 11. September 2003, 14:20: Message edited by: Paul A. Nelson ]
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yersinia
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Member # 324
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posted 11. September 2003 15:13
Well, Paul, before I cite something, why don't you tell us what degree of statistical confidence you would accept? You and Remine here have been arguing that incongruence between phylogeny and stratigraphy is a significant problem for evolution. Remine even alleges that evolutionists are so intellectually bankrupt that they make no predictions on the matter.
If common descent is true, there should be highly significant positive correlation between the fossil record and independently-derived phylogenies. If I can demonstrate this, will you or won't you concede that this is a point in favor of common descent? And linked to this, won't you concede, contra Remine, that common descent is indeed testable on at least this point?
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Grape Ape
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Member # 399
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posted 11. September 2003 16:36
Walter writes:
quote:
That's an illusion. The key evolutionary mechanisms have never been experimentally demonstrated over macro-evolutionary scales. Think of the classic examples: descent with modification, "convergence," atavism (i.e. genetic throwbacks). All those were strongly embraced even by early Darwinians. These were not experimentally demonstrated over large-scales in any clear fashion, yet evolutionists firmly embraced these explanations anyway.
Good grief, what do you want us to do, wait millions of years to see if these things happen? Go back in time and set up a video recorder? You may as well demand that geologists experimentally demonstrate mountain building. Of course, we can see mountains grown by centimeters a year, and extrapolate backwards from that, but then again this is exactly what we do with evolution.
quote:
Previously I correctly listed various evolutionist explanations for "out-of-sequence" fossils. There is no dispute whatever that evolutionists use these.
Once again, what you're doing is claiming that there's no pattern (or that a pattern is not predicted) simply because anomalies exist, and we have an explanation for them. This is just not logical. It is possible both to predict an observed pattern and also explain the rare deviations from that pattern. There is simply no reason why the explanation for the anomaly negates the expectation of the pattern.
Consider the following exchange:
quote:
Person A: New Zealand has no mammals, but it has highly unique birds species (found nowhere else) that fill the niches that mammals usually fill. Evolutionary theory predicts that geographic isolation should produce unique species, and that these species should most closely resemble those which were able to migrate from a nearby land mass.
Person B: But New Zealand does have mammals; sheep live there!
Person A: But the sheep were brought by humans -- they were absent before that.
Person B: AHA! You evolutionists have an answer for everything! See, evolutionists can't predict unique species for New Zealand because they use various excuses for when their theory fails! It can accomodate anything!
I apologize if that strikes anyone as a straw-man, but it's basically what I'm seeing here. I could have made similar examples with the fossil record or phylogenetics. The patterns that evolution predicts are disregarded merely because there exist exceptions, and those exceptions have explanations. However, it is simply not logical to insist that evolutionary theory doesn't make predictions based on biogeography, or that those predictions don't hold true simply because there exists an easily explained anomaly.
quote:
As I said, trilobites are the "rabbits in the Cambrian", and trilobites are every bit as potent as evidence against evolution.
That's just bizzare. I'm afraid you've done nothing to explain why we shouldn't expect trilobites in the Cambrian. They're primitive arthropods, and we find them exactly where we should find them according to the phylogenetic tree. Rabits, on the other hand, contain many derived characters that we shouldn't expect to see until well after the appearance of primitive mammals. Maybe you don't understand that the issue is not about complexity per se, but instead has to do with the sequence in which fossils first appear.
quote:
I disagree. Macro-evolutionary theory is a structureless smorgasbord. It makes no predictions.
Well, we've tried to point out some predictions. Your argument rests on the fact that there exist exceptions to the rule, and that those exceptions have explanations. But like I've said already (and in my previous post) this doesn't change the fact that predictions exist. To think of a few off the top of my head:
- Nested heirarchy.
- Patterns of biogeography -- unique species in isolated environments, etc.
- Fossil record shows that recent animals are more similar to extant ones than ancient animals; the existence of transitional forms, etc.
- Independent convergence of phylogenetic trees from different methods (genetic, morphological, paleontological, etc.)
...and there are many more. I have no doubt that if you try hard enough, you can find a minor exception, anomaly, disputed case, etc. for each of these. But of course my whole point is that common descent predicts a pattern, and that this pattern holds. You can't say that it doesn't make these predictions merely because there are a handful of exceptions, and that these exceptions can be explained. Common descent can certaily be disproven, but to do so you will have to demonstrate that these patterns do not exist, or that contrary patterns exist instead.
quote:
"But you guys are trying to pretend as if evolutionary theory doesn't make predictions simply because there also exist explanations for the anomalies. That's just weird." (Grape Ape, 09/10/2003)
That's not quite it. Evolutionary theory doesn't make predictions, because it is a structureless smorgasbord of every conceivable natural explanation.
No, that's the straw-man caricature that you guys have convinced yourself is real. Evolutoinary theory does not include every conceivable natural explanation -- not even every known natural explanation. I'm afraid this straw-man enjoys so much longevity because of a tendancy to think in terms of false dichotomies. (i.e., It's either "any conceivable natural explanation" or it's God.)
There's a difference between having more than one explanation for some phenomena, and having mutually exclusive explanations. For example, there's a professor in my department that has a natural explanation for life's diversity. It's not evolution, nor is it compatible with evolutionary theory. If his explanation turns out to be true, then evolution is false. I don't take his ideas seriously, but it remains nevertheless that one can have a natural explanation that doesn't include common descent. Conversely, one can have a natural explanation (like HGT) that is orthogonal to common descent and exists side-by-side with it.
quote:
"Secondly, common descent is only as good as it's ability to explain the similarities and differences between organisms. Take away its ability to explain these things (by having sequences be randomly distributed, or by getting rid of the hierarchy) and there's no need to invoke it. We would instead invoke HGT, or whatever other process, and toss common descent by the wayside." (Grape Ape, 09/10/2003)
That's a totally accurate statement of evolutionist thinking. That is, evolution is a no-lose, no-risk proposition, and is not driven by experimental demonstrations of its claims, instead it is driven by pattern. He says, if common descent could not explain the pattern then "there's no need to invoke it" so "toss common descent by the wayside" and "instead invoke HGT, or whatever other process". Modern macro-evolutionary theory is structureless and doesn't predict anything, it is merely adapted, post hoc, to fit the observed data.
You've totally missed my point, but ironically you seem to agree with it. You and Paul have claimed that common descent is protected from empirical disconfimation. I've pointed out that we "evolutionists" would toss aside common descent if the patterns it predicts didn't show up. You agree with me! So now we can hopefully move beyond the bogus claim that the status of common descent is impervious to empirical evidence. The fact that there may be other explanations besides common descent (whether natural or supernatural) is completely irrelevant. The question is whether we would stick to common descent no matter what the empirical evidence showed. As you have agreed, the answer is "no".
And you know, a theory is supposed to be made to fit the data. That would include, for example, adding on additional mechanisms as they're found to increase the theory's scope and explanatory power.
quote:
Given such incredible flexibility, what would cause evolutionists to abandon common descent?
If the empirical evidence didn't favor it, I would abandon it.
A better question is, what would cause you to accept common descent? What empirical evidence would you find convincing?
quote:
* Rabbits/trilobites in the Cambrian, (and other organisms in the Cambrian Explosion).
I still have no idea why you think trilobites in the Cambrian are problematic. They don't defy the expected phylogenetic tree, so I'd say they fit right in. A rabbit on the other hand would be a severe anomaly that would cause us to seriously question evolutionary theory. Why do you think creationists have peddled fake human and dinosaur footprints next to each other? It's because they know that such an occurance would be a major problem for evolutionary theory.
quote:
[b]* The systematic absence of clear-cut lineages over large-scales. (This was a key motive force in the rise of punk ek theory, and the diminution of classical Darwinism.)
I'm not sure what you mean here, but Punk Eek was meant to explain speciation; in other words, small-scale differences between species.
quote:
* The systematic absence of gradualism over large-scales, (as measured by what we can experimentally demonstrate today).
Again, this is confusing. If by "gradualism" you mean relatively small changes in a lineage over time, then we observe just that. Some common examples include fossil hominids, whales, reptile-mammals, and dino-birds. Even better examples exist for marine fauna.
quote:
* The existence of a risky, scientifically testable, ID theory that explains the major patterns of life (including life's substantial hierarchical patterns, life's profound biochemical unity, the abundance of so-called "convergence," and many others).
Even if such a thing ever emerged (and I'm not holding my breath) then it wouldn't necessarily cause anyone to abandon common descent. (Again, I think this is false dichotomy thinking.) Only once the ID theory in question proved to be better at explaining the evidence and passing empirical tests would it be preferred. But I have yet to see one that isn't entirely ad hoc and could possibly be addressed with empirical evidence (and that includes your so-called "message theory"). This makes your claims about common descent pretty ironic.
[ 11. September 2003, 16:40: Message edited by: Grape Ape ]
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Nel
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Member # 614
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posted 11. September 2003 16:37
Charlie writes:
quote:
If every tree looked different from every other tree, all you could conclude is that there is no evidence of vertical transmission, without which speaking of "horizontal" is meaningless. Basically, you'd say that all species are genetic mosaics, and all mechanistic hypotheses (massive transfer of genes between lineages, whimsical designer, completely independent evolution of every lineage, etc etc) would be equivalent in the absence of other data
Why would you say that ”horizontal” is meaningless in the absence of vertical transmission? After all vertical is certainly not meaningless in the absence of horizontal. We should be able to detect massive horizontal transfer through the complete jumble that would result for species relationships, if you could even talk about species in this limit. If all species were genetic mosaics, would that not also say that massive transfers are common and vertical evolution obscured? I can't see any reason whatsoever why all mechanistic hypotheses would become equivalent in this case.
[ 11. September 2003, 16:38: Message edited by: Nelson-Alonso ]
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