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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 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

This message is a reply to:
 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

  
Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 78 of 86 (198528)
04-12-2005 9:44 AM
Reply to: Message 77 by mark24
04-12-2005 5:38 AM


Re: OK Faith, so how about it?
mark24 writes:
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.
Can you describe how this simplified cladogram example correlates with stratigraphic evidence to provide supporting evidence for evolution?
--Percy

This message is a reply to:
 Message 77 by mark24, posted 04-12-2005 5:38 AM mark24 has replied

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 Message 80 by mark24, posted 04-12-2005 10:36 AM Percy has not replied

  
Admin
Director
Posts: 12998
From: EvC Forum
Joined: 06-14-2002
Member Rating: 2.3


Message 79 of 86 (198541)
04-12-2005 10:24 AM
Reply to: Message 64 by Faith
04-11-2005 1:47 PM


Re: OK Faith, so how about it?
Hi Faith,
I could use some help over at [forum=-25]. New member ptolemy is trying to propose a new thread, and what he's saying makes little sense to me and even appears contradictory. Can you take a peek at Is the Bible supported by Science?. If I'm just not understanding what he's saying could you explain it to me? And if he's actually not being clear, could you help guide him along? I've given you posting privileges in [forum=-25] so you'll be able to post replies there.

--Percy
EvC Forum Director

This message is a reply to:
 Message 64 by Faith, posted 04-11-2005 1:47 PM Faith has replied

Replies to this message:
 Message 81 by Faith, posted 04-12-2005 2:22 PM Admin 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

  
Faith 
Suspended Member (Idle past 1444 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 81 of 86 (198671)
04-12-2005 2:22 PM
Reply to: Message 79 by Admin
04-12-2005 10:24 AM


Re: OK Faith, so how about it?
Thanks for the trust, Percy, I much appreciate it, but having read through Ptolemy's exchange with you I'm afraid I can't make much sense out of it, not even enough to venture to help him sort it out at this point.

This message is a reply to:
 Message 79 by Admin, posted 04-12-2005 10:24 AM Admin has replied

Replies to this message:
 Message 82 by Admin, posted 04-12-2005 2:29 PM Faith has replied

  
Admin
Director
Posts: 12998
From: EvC Forum
Joined: 06-14-2002
Member Rating: 2.3


Message 82 of 86 (198676)
04-12-2005 2:29 PM
Reply to: Message 81 by Faith
04-12-2005 2:22 PM


Re: OK Faith, so how about it?
Okay, thanks for trying!

--Percy
EvC Forum Director

This message is a reply to:
 Message 81 by Faith, posted 04-12-2005 2:22 PM Faith has replied

Replies to this message:
 Message 83 by Faith, posted 04-14-2005 2:00 AM Admin has replied

  
Faith 
Suspended Member (Idle past 1444 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 83 of 86 (199132)
04-14-2005 2:00 AM
Reply to: Message 82 by Admin
04-12-2005 2:29 PM


Re: OK Faith, so how about it?
Um, how did I get to be "Moderator" and what does it mean?

This message is a reply to:
 Message 82 by Admin, posted 04-12-2005 2:29 PM Admin has replied

Replies to this message:
 Message 84 by Admin, posted 04-14-2005 8:59 AM Faith has not replied

  
Admin
Director
Posts: 12998
From: EvC Forum
Joined: 06-14-2002
Member Rating: 2.3


Message 84 of 86 (199194)
04-14-2005 8:59 AM
Reply to: Message 83 by Faith
04-14-2005 2:00 AM


Re: OK Faith, so how about it?
Whoops - accidental side effect of giving you posting privileges in PNT. Fixed now.
Interesting that this came up, though. I think you'd make an excellent moderator. Adminnemooseus is in charge of moderator recruitment, I wonder if he agrees.

--Percy
EvC Forum Director

This message is a reply to:
 Message 83 by Faith, posted 04-14-2005 2:00 AM Faith has not replied

  
sfs
Member (Idle past 2533 days)
Posts: 464
From: Cambridge, MA USA
Joined: 08-27-2003


Message 85 of 86 (199555)
04-15-2005 10:08 AM
Reply to: Message 44 by Faith
04-10-2005 2:10 AM


quote:
But there's no way to test/verify/falsify that the rate of decay is constant for all spans of time and all conditions and the only way this could be verified is with a sample whose date is known. YOu are in the position of simply trusting that it holds up, but you can't know that.
No, that's not true. There are a number of steps physicists can take (and have taken) to determine whether radioactive decay rates change. First, you can understand why decay takes place, i.e. develop a good nuclear theory, and then predict based on the theory how decay rates would change for various conditions. Physicists have done that. Based on their theories, they predict that most decay rates would change not at all in any kind of environment relevant to dating rocks (e.g. we don't have to ask what would happen to decay rates at the center of a supernova or in a neutron star -- the fact that the rocks are sitting in an intact Earth sets constraints on what conditions they might have experienced). One kind of decay (electron capture) can change slightly as pressure increases, but this would involve no more than a small correction factor, and does not apply to most dating techniques.
Second, they can test their predictions: measure decay rates under increasing pressure, for example, or at different temperatures. The predictions turn out to be quite accurate.
Third, they can test lots of other predictions made based on the same nuclear theory. The same theory predicts, for example, how stars behave, and how nuclei interact when you slam them together in accelerators. Again, the theory appears to be quite sound. (Lots of details can't be calculated from existing theory; that's why physicists do experiments. But none of the uncertainty, and none of the experimental results, has given any hint that the basic conclusions about the constancy of decay rates are wrong.)
Fourth, they can use astronomy to see if nuclear reactions behaved differently in the past. Looking at stars that are different distances away, for example, shows that nuclear reactions (which power stars) behaved identically over a vast range of times, from a few years to many millions of years. (This is because light takes a long time to reach us from distant stars, so the light we're seeing now was produced millions or billions of years ago.)
Fifth, they can compare different dating methods for the same samples. It's hard to imagine any mechanism for decay rates to change, but it's much harder to imagine a mechanism that would have only the effect of speeding up all known decay rates (and without introducing any new unstable isotopes). Different dating techniques give consistent answers in the vast majority of cases.
Sixth, they can look at specific events that occurred in the past. Specifically, they can study the Oklo reactor, which was a natural fission reactor that occurred in uranium ore deposits in what is now Gabon a couple of billion years ago (according to conventional dating, that is). The particular mix of reactor products produced turns out to be a very sensitive test of whether nuclear reactions have changed at all since the reactor operated, and the conclusion is that they haven't.
You see, physicists don't just assume that physics, and decay rates, haven't changed. They have investigated the possibility of change as an interesting scientific hypothesis, and have used a variety of techniques to set very stringent limits on how much change can have occurred. There's an entire little subfield of physics that tests things like this.

This message is a reply to:
 Message 44 by Faith, posted 04-10-2005 2:10 AM Faith has not replied

Replies to this message:
 Message 86 by Loudmouth, posted 04-15-2005 4:40 PM sfs has not replied

  
Loudmouth
Inactive Member


Message 86 of 86 (199621)
04-15-2005 4:40 PM
Reply to: Message 85 by sfs
04-15-2005 10:08 AM


My two cents on the constancy of decay rates.
The first is nuclear power plants. If decay rates can vary for no reason and vary drastically this would mean that nuclear power plants will either blow up or stop working. Physicists and engineers would not have built these facilities, and continue to build them, if decay rates were not understood.
Secondly, the decay rate of an unstable isotope is as much a characteristic of that element as density, reactivity, etc. You might as well argue that water used to have the formula of H4O, or that it's density at sealevel used to be 0.1 g/ml. Of course, we all know why creationists want varying decay rates. They want a young earth and decay rates get in the way. They do not claim that decay rates vary because of evidence but because of the conclusions it leads to.

This message is a reply to:
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