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Author Topic:   The Nature of Scientific Inquiry; Is Evolution Science?
mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 12 of 86 (195514)
03-30-2005 4:26 PM
Reply to: Message 6 by Faith
03-30-2005 11:47 AM


Re: OK Faith, so how about it?
Hi Faith,
I have generally followed threads you have been involved in, but decided not to post, too many of us piling it on wouldn't really help you deal with the points raised. But since this is a new thread I'll wade right in. I'd like to tackle two points, the "what is science" bit, then evidence of macroevolution if I may.
Science is simply a logical methodological construct that allows hypotheses to be supported or falsified. Data that becomes available that supports a hypothesis is by definition evidence for it, & vice versa.
You cannot prove anything that happened in the past
Science doesn't "prove" anything, it simply piles on the evidence to such a point that it would be foolish to deny the theories veracity. In order to be scientific, a theory must be open to revision in the face of new data, yes? Not even creationists deny that. If this is the case then it therefore obvious that one cannot prove a theory to the point where you can state it with absolute 100% certainty. If you do, then you are stating that no new data could possibly be considered, which is of course contradictory, & no scientific theory would or could be held in this regard & still be considered scientific.
If a theory hypothesises that something happened in such a way in the past, & data supports that theory, then that data is evidence of it, by definition. It matters not one iota whether that data supports a real-time experiment in a lab, or a hypothesis that Egyptians preserved their nobility for an alleged afterlife by embalming them. Nowhere, & I mean nowhere, in any scientific or philosophical literature does it state that past events cannot be inferred. This notion is simply an illogical tactic invoked by creationists so they don't have to consider data. It is of course ridiculous that creationists insist that data in support of a theory isn't evidence of it, but there you go!
Now, on to the juicy stuff. This is technical, but I hope I've done a reasonable job in simplifying the concepts.
Cladistics is a method by which we look at as many characters as possible in a given species, & compare them to other species. In such a way we can assess similarities between species & more easily classify them. The result is a diagram like this...
You may note that the most similar organisms are likely to be the most related, according to evolutionary theory. Therefore, the resulting cladogram, as well as being an objective method of classification, also shows us relationships between taxa if evolution is indicative of reality. If so, we can think of a cladogram as being akin to an evolutionary tree.
A very big "if", I hear you say! How can we test the assumption that relationships between organisms on a cladogram are evolutionary in origin? Two ways, take different data sets & see if the cladograms broadly match (they do), or test the cladograms order of divergence (the point where lineages diverge are called "nodes" on a cladogram) & see how well it matches the rocks. This is the beautiful bit, at a stroke it shows the geologic column to be indicative of reality, as well as evolutionary principles. The matches aren't perfect by any stretch, but when taken en mass, they show a correlation that far, far exceeds what would be expected by chance alone.
We have our data that supports evolution.
Take a deep breath for more detail, showing the extent & quality of the evidence......Here goes.....
Given that the cladograms under study are independent of stratigraphy, it is possible to compare the two to see how well they match. There are two main reasons for disagreement. 1/ The cladogram is wrong, & 2/ the fossil record is so poor that the daughter species is found in older rock than the parent. Given that this is the case, we should expect a very low SCI (SCI is the ratio of stratigraphic consistent to inconsistent nodes in a cladogram) value if evolution were not indicative of reality. ie. Nodes (in complex cladograms) match by chance rather than signal. In other words, the null hypothesis is that the SCI value will be a low value.
Assessing Congruence Between Cladistic and Stratigraphic Data
Stratigraphic Consistency Index
"The SCI metric may also be summarized either as a mean value for each taxonomic group or as a proportion of cladograms that score SCI values of 0.500 or more, an indication that half, or more, of the branches are consistent with stratigraphic evidence. By both measures, fishes and echinoderms score better than tetrapods. Mean SCI values are: echinoderms (0.773), fishes (0.757), and tetrapods (0.701). Proportions of cladograms with SCI values $0.500 are tetrapods (100%), echinoderms (94%), and fishes (93%). For both measures, values for all three groups are indistinguishable according to binomial error bars (Fig. 3).
Within the sample of echinoderm cladograms, nonechinoids show somewhat better results than echinoids but not significantly so (Fig. 3). The mean SCI value for echinoids is 0.724, and for nonechinoids 0.849; moreover, 90%of echinoid cladograms have SCI values $ 0.500,compared with 100% for nonechinoids.
SCI values for fish groups are variable but not significantly different (Fig. 3). For mean SCI values, the order is as follows: sarcopterygians (0.904), teleosts (0.744), placoderms(0.741), agnathans (0.733), and actinopterygians (0.722). In all cases, all sampled cladograms show SCI values > 0.500. The rankings of tetrapod groups by both aspects of the SCI metric are comparable. Mean SCI values give this sequence: mammals (0.837), mammallike reptiles (0.729), lepidosauromorphs (0.714), dinosaurs (0.698), archosauromorphs (0.660), and turtles (0.586). The low value for turtles is significantly lower than the high values for synapsids, mammals, and mammallike reptiles. Proportions of cladograms with SCI values $ 0.500 give this sequence: mammals (100%), mammallike reptiles (100%), lepidosauromorphs (100%), turtles (100%), dinosaurs (86%), and archosauromorphs (78%)."
Why is the SCI so high? Why do cladograms & stratigraphy match on the whole if evolution is not indicative of reality? Given that cladograms & stratigraphy match relatively well, how do you explain this significant correlation?"
Given there is a clear signal of "evolution" in the rock stratigraphy & morphology combined, it therefore stands to reason that where these phylogenies would infer large scale morphological change (Cetaceans, basal tetrapoda, & basal amniotes, for example), evolution can be reliably inferred. Even more reliably than phylogenetic analyses, cladistics & stratigraphy on their own, that is.
(Thanks to Rrhain for the maths help.)
The average cladogram has six taxa, meaning five nodes. Giving you the benefit of the doubt for ease of calculation we’ll assume only 60% (average) nodes (rather than ~75%) corroborate.
C(n,k) * r! * {1 - [1 - 1/2! + 1/3! - 1/4! + ... + (-1)^(r+1)*1/r!]} / n!
n= total no. of nodes
K= correct nodes
r= n-k= incorrect no. of nodes
C(5,3) * 2! * [1 - (1 - 1/2!)] / 5!
10 * 2 * (1/2) / 120
10/120
1/12
There is a 12:1 chance of getting the average cladogram to match stratigraphy as well as it does. There is therefore a 12^300:1 chance of getting 300 cladograms to match stratigraphy in this way.
5.68*10^323:1
568,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 : 1 chance of 300 cladograms enjoying a 60% corroboration with stratigraphy.
As can be seen, the evidence piles up when more & more cladograms are considered.
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 6 by Faith, posted 03-30-2005 11:47 AM Faith has replied

Replies to this message:
 Message 46 by Faith, posted 04-10-2005 3:46 AM mark24 has replied

  
mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 25 of 86 (195961)
04-01-2005 4:33 AM
Reply to: Message 6 by Faith
03-30-2005 11:47 AM


Re: OK Faith, so how about it?
Hi Faith,
Would it be possible to respond to at least the first four paragraphs in post 12, please?
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 6 by Faith, posted 03-30-2005 11:47 AM Faith has replied

Replies to this message:
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mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 28 of 86 (195980)
04-01-2005 7:08 AM
Reply to: Message 27 by Faith
04-01-2005 4:51 AM


Faith,
Yes, you can prove/disprove some things for the recent past, but what you have for a starting point is something you KNOW happened in the past that you are investigating, the rape murder -- you must have a witness or clear known event from the past for this method to work.
I'm sorry, Faith, but this is pure nonsense. The "must have a witness" rule is clearly a device invoked so that you can ignore evidence of things unpalateable to you.
A hypothetical scenario.
The facts. A womans dead body is found in a wood, she has multiple deep lacerations over her naked body that match the size of the bloody axe laying next to her. She has other cuts & lacerations as well. The axe is covered with person X's fingerprints. The woman has person X's semen inside her, & person X's skin is under her fingernails & in the smaller lacerations on her body. There are no witnesses.
Clearly a case of death by natural causes, right?
The inferences; a woman was raped, there was a struggle, & she was murdered with an axe. She fought person X, which is how she got his skin under her fingernails & in her cuts, she was raped by person X, which is how she got his semen inside here, & person X killed here with the axe, which is why it has his fingerprints on it.
Eyewitness evidence is the very worst, most unreliable evidence it is possible to have. Hard, physical evidence is preferable every time. It is obviously a reasonable inference that the woman was murdered by X. We did that with no witness. The inference that the woman was 1/ murdered, & 2/ was murdered by X, was not a "clear known event", it was inferred purely from physical evidence.
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 27 by Faith, posted 04-01-2005 4:51 AM Faith has replied

Replies to this message:
 Message 32 by Faith, posted 04-01-2005 3:00 PM mark24 has replied

  
mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 37 of 86 (196077)
04-01-2005 4:17 PM
Reply to: Message 32 by Faith
04-01-2005 3:00 PM


Faith,
You missed the point. The point is that you must have SOMETHING in the past that is known, which includes witnesses if there are any.
And my point is that you don't. We have a body with deep cuts all over it that couldn't have been self inflicted. We don't know in advance that there was a murder, we infer it from the evidence; that there were signs of a struggle, & fatal wounds that the victim could not possibly of inflicted on herself. Ergo, we infer a murder occurred without a witness. What do you think was the most likely explanation? What hypothesis does the data best explain?
In a crime scene in recent time you are STARTING from knowns: you have the dead body and can figure out when it happened, and there's other evidence to work from to get at what may have happened. Try to follow the argument here. Are you going to send a man up for murder on nothing but your inferences from the physical evidence?
Yes, I am going to send a man up for murder on inferences from physical evidence, & it happens all the time. I AM figuring out what happened, it is you that refuse to send a murderer to prison, not I. If you think there is mitigating evidence, then you need to show it. Otherwise the evidence easily supports the hypothesis that X murdered the victim.
Are you seriously suggesting that we cannot 1/ determine a murder occurred, & 2/ determine that X committed the murder?
Now, I'll agree that DNA is pretty definitive if you have it, depending on where it is found and whatever is known about a possible relationship between the deceased and the suspect, but the rest could have been planted.
Yeah, but without an eyewitness you can't infer that evidence was planted, right? Seriously, you can hypothesise that the evidence was planted (I'd love to know how you think X's spunk got inside the witness, how his fingerprints got on the murder weapon, & how bits of X's skin got under the fingernails of the victim without him realising he was being set up), but unless your hypothesis has evidence in its support, it must be rejected.
In any case you have MUCH evidence of many kinds that may eventually solve the crime for you. And witnesses would be a BIG help.
Not necessarily, they may be lying, mistaken, &/or have alterior motives of their own. This is why eyewitness evidence is so inferior. Physical evidence does not lie.
What, based on the evidence, is the most likely explanation of the facts?
A response message 12 would be appreciated, thanks.
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
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mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 40 of 86 (196107)
04-01-2005 6:26 PM
Reply to: Message 39 by Nighttrain
04-01-2005 6:13 PM


No, death by natural causes, maybe suicide, without a witness, you can't infer murder, remember!

This message is a reply to:
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mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 41 of 86 (196849)
04-05-2005 4:43 AM
Reply to: Message 37 by mark24
04-01-2005 4:17 PM


bump

This message is a reply to:
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mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 50 of 86 (198038)
04-10-2005 10:27 AM
Reply to: Message 46 by Faith
04-10-2005 3:46 AM


Re: OK Faith, so how about it?
Hi Faith,
OK, Mark, I'm finally getting back to your Post #12. Sorry I've kept you waiting so long.
Not a problem, I understand that you are replying to lots of people.
Science doesn't "prove" anything, it simply piles on the evidence to such a point that it would be foolish to deny the theories veracity.
Well, then, tell everyone to stop claiming that science requires falsifiability, testability, replicability, etc., all the methods of old-fashioned laboratory science.
Your comment doesn't follow from mine. How did you get from the tentativity of scientific conclusions, which you accept, to the non-requirement of testability, falsifiability, & replicability? What I said does not require that testability et al be surrendered.
Nor did I say they cannot. I said that all one CAN come up with is plausible inferences for past events. I said the theory of evolution, and the Geo Timeframe or Old Earth Theory, both THEORIES about what happened in the past, are what cannot be tested, falsified, replicated and so on.
But I have shown you a study that does exactly what you say cannot be done. The ToE is objectively tested with cladisics against stratigraphy.
But of course many things can be inferred, and then the question is how good is the inference and can the inference --- which, come to think of it, is really a theory or hypothesis, isn't it? ---- be proved or corroborated? An inference about, say, some details in a crime scene, and even the solution to the crime itself, CAN sometimes be pretty much proved if there's lots of data, lots of evidence to check out. But an inference about the distant past cannot be proved, or an inference about any event for which there is no independent evidence.
And the odds of evolutionary expectations being due to chance being 5.68*10^323:1 doesn't constitute high quality evidence to you?
I studied the diagrams and they appear to be four identical diagrams slightly differently drawn, with one rotated 90 degrees, so I don't see why four were needed and that starts me off wondering what's going on.
That's just an example so you can visualise what a cladogram is. The actual study conducted by Benton correlates 300 (now over a thousand) cladograms against stratigraphy. Just to clarify, I'm not attempting to show you the tree of life, just that individual, independant cladograms match stratigraphy against the odds, & that it is therefore statistically significant.
In the end I'm not really sure you've proved anything more than is already inferred from the appearance of the fossil record itself --that is, the appearance of a hierarchy of morphologies represented there, which is what suggested the idea of evolution in the first place. What the cladogram does is refine this basic inference. I'm really not sure it's added anything new. Maybe I'm just not understanding it well enough, and it is suggestive, even interesting.
I'm not sure how you can come to such a dismissive conclusion. I really don't think that you understand the significance of the evidence. If I can pick up on the notion that the evidence only restates an original premise of evolution, that is that there is a heirarchy of morphologies. This is false, the original observation was that there were specific biotas associated with specific relative age groups. The inference being that biota A got to biota B via evolution. What I have presented to you confirms that a morphological ordering occurs in the rocks consistent with evolution. It does so by noting that the stratigraphic ordering is actually what is expected by evolution, by studying the grade of morphological dis/similarities, objectively determined by cladistic methods. This is extremely unlikely to be the case unless evolution occurred (5.68*10^323:1). In other words, if evolution hadn't occurred, then we wouldn't expect the specific stratigraphic locations of fossils to correlate with cladograms.
But they do correlate, & overall, they do so spectacularly. And as I noted above, this is statistically significant evidence of evolution in general, & where the cladograms test taxa that are significantly different morphologically, is significant evidence of macroevolution.
Mark
This message has been edited by mark24, 04-10-2005 09:30 AM

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 46 by Faith, posted 04-10-2005 3:46 AM Faith has replied

Replies to this message:
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 Message 57 by Faith, posted 04-10-2005 9:44 PM mark24 has replied

  
mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 60 of 86 (198295)
04-11-2005 12:13 PM
Reply to: Message 57 by Faith
04-10-2005 9:44 PM


Re: OK Faith, so how about it?
Hi Faith,
At first when I read it, it did appear to be saying something significant as you claim, but after thinking about it twice now I don't see that. We ALREADY acknowledge that a morphological ordering occurs in the rocks that is interpreted to be consistent with evolution. Seems to me you have only confirmed that the apparent morphological ordering that appears in the rocks is also reflected in detailed morphological comparisons between the species represented there.
If you acknowledge that a correlation exists, then why are you saying there is no evidence of macroevolution? This is extremely puzzling. If data that supports a theory is by definition evidence of it, which you admit in post 46, then by making the above admission you are implicitly admitting that evidence of evolution exists.
My job is done. If you accepted the correlation anyway, all I have done is to show you that this correlation pervades all levels & resolutions of the fossil record, micro to macro, at colossal odds of it existing by chance. It is not a trivial discovery.
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 57 by Faith, posted 04-10-2005 9:44 PM Faith has replied

Replies to this message:
 Message 61 by Faith, posted 04-11-2005 12:27 PM mark24 has replied

  
mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 63 of 86 (198308)
04-11-2005 12:58 PM
Reply to: Message 61 by Faith
04-11-2005 12:27 PM


Re: OK Faith, so how about it?
Faith,
You are being evasive, I have carefully defined terms & gained agreement from you in earlier posts. I have made a perfectly reasonable, logical, & evidentially supported case.
You agree that data that supports a theory is evidence of it, & you accept that a correlation between stratigraphy & morphology exists as expected by evolutionary theory. Moreover, I have presented evidence that is expected by evolutionary theory, & where taxa of relatively large scale morphological differences are involved, is expected of macroevolution. Ergo there IS evidence of macroevolution.
It is therefore hypocritical for you to say that there is no evidence of macroevolution when data is presented that is expected by, & therefore supporting of, macroevolution.
Evidence & proof are not the same thing.
you can't prove evolution by the ordering of the fossils no matter how refined.
I am not attempting to prove anything, I am attempting to show you evidence of something. You agreed in message 46 that scientific theories MUST be open to revision, & therefore cannot ever be considered proven. Having done so, it is simply dishonest to continue to use the word "proven" when alluding to scientific theories in general, & particularly when no-one is attempting to prove anything to you anyway.
Mark
This message has been edited by mark24, 04-11-2005 12:23 PM

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 61 by Faith, posted 04-11-2005 12:27 PM Faith has replied

Replies to this message:
 Message 64 by Faith, posted 04-11-2005 1:47 PM mark24 has replied
 Message 67 by Percy, posted 04-11-2005 2:45 PM mark24 has replied
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mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 69 of 86 (198364)
04-11-2005 4:43 PM
Reply to: Message 64 by Faith
04-11-2005 1:47 PM


Re: OK Faith, so how about it?
Hi Faith,
Some of this is just semantic, Mark. So OK you prefer "evidence of macroevolution" to "proof of macroevolution" and that's probably more accurate, but I still read this evidence as not evidence of macroevolution at all but circular reasoning or even tautology that confirms only what it already assumes.
There is no circularity. For an argument to be circular it has to assume the conclusion in order to accept the premise, since post 12 does not do this your objection is moot. It is a perfectly legitimate, logically sound argument.
Nor is it semantics. The purpose of agreeing terms is so that a rational discussion can take place within agreed parameters, & no semantic bullpuckey can take place. You agreed terms & are now backpedalling as fast as you can. This is simply dishonest.
If you are going to maintain that I commit the logical fallacy of circular argumentation, then you had better show exactly where I am forced to accept my conclusion before I can accept my premise.
Given that you can't, you may wish accept that I have presented data that supports evolution, & that it is evidence of it.
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 64 by Faith, posted 04-11-2005 1:47 PM Faith has not replied

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mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 70 of 86 (198365)
04-11-2005 4:53 PM
Reply to: Message 67 by Percy
04-11-2005 2:45 PM


Re: OK Faith, so how about it?
Hi Percy,
It might be helpful if you provided an example or two of specific morphological characteristics and how cladistics organizes them to find correlations with the fossil record.
I disagree, that there is a morphological vs. stratigraphic correlation is accepted by Faith, the problem is her logic in denying that it is evidence of evolution. It would involve a lot of work demonstrating something that isn't being contested anyway.
Perhaps an example of the characters used in constructing a phylogeny might prove useful?
Mark
This message has been edited by mark24, 04-11-2005 03:55 PM

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 67 by Percy, posted 04-11-2005 2:45 PM Percy has replied

Replies to this message:
 Message 72 by Percy, posted 04-11-2005 5:02 PM mark24 has replied

  
mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 73 of 86 (198371)
04-11-2005 5:26 PM
Reply to: Message 72 by Percy
04-11-2005 5:02 PM


Re: OK Faith, so how about it?
Hi Percy,
Well, yes, but as Linear pointed out, it isn't clear she understands the evidence derives from independent sources.
It is for anyone who read post 12.
Plus it was a question she specifically asked. Why wouldn't you answer it? If cladistics is your thing, then why wouldn't you take every opportunity to tell anyone who expressed an interest anything they wanted to know?
Because it simply wasn't directly relevant to the differences currently under discussion. Faith accepts that morphology/stratigraphy show a correlation, in fact she hand waves the evidence away because of it (!). What's the point in waxing lyrical about something that is accepted & isn't going to move the discussion on? It was simply more time efficient to focus on the area of difference between us, which is now of a purely logical rather than physical or methodological nature.
Mark

This message is a reply to:
 Message 72 by Percy, posted 04-11-2005 5:02 PM Percy has replied

Replies to this message:
 Message 74 by Percy, posted 04-11-2005 8:52 PM mark24 has replied
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mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 76 of 86 (198454)
04-12-2005 5:10 AM
Reply to: Message 74 by Percy
04-11-2005 8:52 PM


Re: OK Faith, so how about it?
Percy,
Not to get into a meta-discussion, but I just don't follow your logic. And if I who accept your cladistics argument don't follow your logic for not providing more information and explanation, then Faith who rejects your argument certainly doesn't follow it.
Faith does accept the cladistic argument per se, her grasp may be simplistic, but then that is all that's reqired. I am attempting to show that evolutionary expectations are borne out in the fossil record, Faith accepts this. Job done, move on. What she doesn't accept is that this is evidence of evolution. In other words, her argument is about what-evidence-is, rather than a non-acceptance that "morphological grades" predicted by evolution actually exist in the fossil record.
In post 57 Faith states:
We ALREADY acknowledge that a morphological ordering occurs in the rocks that is interpreted to be consistent with evolution.
I repeat, because it's a point I don't think you are getting, this is all that I am attempting to show (that & the sheer unlikelihood of it occurring over & over). Once this was admitted, I can dispense with the cladistic/stratigraphic argument & delve into the unfathomable rationale of why data supporting a theory somehow isn't evidence of it.
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 74 by Percy, posted 04-11-2005 8:52 PM Percy has not replied

  
mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 77 of 86 (198464)
04-12-2005 5:38 AM
Reply to: Message 75 by LinearAq
04-12-2005 4:53 AM


Re: OK Faith, so how about it?
LinearAq,
Unless one understands how they are independent, this seems like a poorly supported assertion. Even the paper in the link you provided assumes that the reader knows the two are independently derived. Faith never acknowledges this statement. In fact, in post 46, she states:
Actually, on reading post again I can see how I may have been equivocal. When I gave my little intro on cladistics I described how "characters" were used in constructing cladograms. What I should have said was that "morphological characters" were used. This is an important distinction because some cladograms are contructed where statigraphic positioning is considered informative (although none of the ones under study), & the cladogram & stratigraphy are not independent. Had I had made the distinction I would have avoided any confusion. Thanks for bringing this to my attention.
However, my message to you is the same as to Percy...
faith writes:
In the end I'm not really sure you've proved anything more than is already inferred from the appearance of the fossil record itself -- that is, the appearance of a hierarchy of morphologies represented there, which is what suggested the idea of evolution in the first place. What the cladogram does is refine this basic inference
This paragraph could be taken two ways, firstly that she understands that different biotas exist at different times, but are not linked in any evolutionary way, or that she agrees that an evolutionary trend exists.
In post 57 Faith states:
faith writes:
We ALREADY acknowledge that a morphological ordering occurs in the rocks that is interpreted to be consistent with evolution.
This shows that she accepts that the ordering is consistent with evolution. Given this is what I am attempting to show, my job regarding that is done. The argument is now one of logic/what-evidence-is, rather than her denial that evolutionary trends exist. Apparently lots of fossils packed into the rocks as expected by evolution isn't evidence of evolution?!
In other words, there is no point elaborating over something that is no longer contested.
One question I have is, how are the nodal points determined on the cladogram?
A node is generated by the method when it determines the pattern of similarities & places a taxon into a more inclusive group. For example, in a three taxa cladogram with a bird, a dog, & a jellyfish, we might include such characters as posession of nematocysts, posession of a skeleton, posession of a pumped vascular sytem, diploblastic, triploblastic etc. This example would show a root node (all the cladograms under discussion are rooted), from which two lines originate, one goes to the jellyfish, one to another node that includes the dog & bird. This node splits into two branches, one with the dog, one with the bird. The reason the bird/dog node is placed where it is, is because the bird & dog possess more similarities with each other than the jellyfish, so they are connected.
Mark
This message has been edited by mark24, 04-12-2005 06:53 AM

There are 10 kinds of people in this world; those that understand binary, & those that don't

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 Message 75 by LinearAq, posted 04-12-2005 4:53 AM LinearAq has not replied

Replies to this message:
 Message 78 by Percy, posted 04-12-2005 9:44 AM mark24 has replied

  
mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 80 of 86 (198546)
04-12-2005 10:36 AM
Reply to: Message 78 by Percy
04-12-2005 9:44 AM


Re: OK Faith, so how about it?
Percy,
Can you describe how this simplified cladogram example correlates with stratigraphic evidence to provide supporting evidence for evolution?
Yes, to put it into perspective & make it relevant, assume that the bird, dog, & jellyfish are fossils that are the earliest examples of their taxon. The earliest cnidarians (jellyfish) appear in the late Precambrian to the lower Cambrian, the clade that contains both birds & dogs appears later in the fossil record. The cladogram is therefore consistent with stratigraphy because the nodes that separate the respective taxa in the cladogram, are in the same ascending order that they are found stratigraphically in the geologic column.
This isn't a particularly good example, due to the low number of taxa. Evolution expects a gradual (he says advisedly) change in characters from form A to form B. So when a cladogram shows us a rooted node with one branch going off to troodontids & dromaeosaurs, & the other immediately hitting Archeopteryx, followed by Rahonavis, the confuciornithidae, the Eunantiorthines, Ornithuromorpha, Ornithurae, Carinatae. We may note that the order that these taxa split off from the cladogram is a function of the spectrum of morphological characters. We start with Archaeopteryx, which is as different from the Carinatae as it is possible to be, & climb up the cladogram getting less like Archeopteryx & more like the Carinatae as we go, exactly as if evolution had occurred. We may also note that this transition is mirrored stratigraphically, we find Archaeopteryx in the geologic column, climbing up the virtual rock face & coming across the taxa in the same order. The ordering of the fossils in the rocks is the same as in the cladogram, & this has no business happening unless evolution were indicative of reality.
The cladogram is derived without reference to stratigraphy, & is therefore entirely independent of it.
Hope that's better.
The reality is that due to a raft of reasons, it rarely happens 100% like this, yet there is a clear signal that far exceeds what you would expect by chance of this correlation.
Mark
This message has been edited by mark24, 04-12-2005 09:39 AM

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 78 by Percy, posted 04-12-2005 9:44 AM Percy has not replied

  
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