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Author Topic:   Anatomical Vestiges -- Evidence of Common Descent
Fallen
Member (Idle past 2046 days)
Posts: 38
Joined: 08-02-2007


Message 23 of 34 (418323)
08-27-2007 2:32 PM


Chiroptera writes:

We're not discussing why, given the existence of this particular organ, it should evolve to have extra lymphoid tissue. The purpose of this thread is to discuss the vestigial nature of the appendix. Creationists claim that the appendix is not vestigial because it has a purpose, and that it's purpose is that it contains lymphoid tissue important for the immune system. The question then becomes why God needed to create a holder for lymphoid tissue that was a blind sac, why a blind sac that looks for all the world similar to an existing, functioning organ in closely related species, and why a blind that can and does kill the person who has it.

The evidence that has been presented here is evidence against a particular version of creationism, not evidence in favor of evolution. The underlying assumption behind the argument is that an Intelligent Designer would never use the same design twice, or would never modify a design for re-use in another organism. I don’t accept that assumption. I, for one, would have a hard time accepting Intelligent Design if no two designs were alike, because that would go against everything we know about clever designs. Smart designers don’t create hundreds of entirely independent concepts. Rather, they use and vary the same design many times. One has only to look at every design from nails to computers to ballistic missiles to see that much. The reason for this principle of engineering is simple – if you only make one kind of a design, you waste a lot of potentially useful similar designs. Likewise, in your example, the designer probably used the appendix design to make a workable addition to the immune system.

Edited by Prodi, : No reason given.

Edited by Prodi, : No reason given.


Replies to this message:
 Message 24 by Coragyps, posted 08-27-2007 2:50 PM Fallen has responded
 Message 26 by Chiroptera, posted 08-27-2007 4:00 PM Fallen has not yet responded

  
Fallen
Member (Idle past 2046 days)
Posts: 38
Joined: 08-02-2007


Message 25 of 34 (418334)
08-27-2007 3:23 PM
Reply to: Message 24 by Coragyps
08-27-2007 2:50 PM


Coragyps writes:

But the human ppendix isn't "a workable addition to the immune system" in any meaningful way at all. It's just a few square centimeters of small intestine with some Peyer's patches on it - like they're on the other square meter or however much of the rest of the small intestine. And it's arranged as a little time bomb that kills 7% or so of (preindustrial) humans at just about the time they're thinking about starting families.
Ill-tempered designer, I'd think.

Regardless, vestigial structures like the appendix are consistent with theories other than evolution. Perhaps it was designed and later corrupted, or we haven’t done enough research yet to uncover its true purpose. In my experience, many supposedly functionless or damaging parts have turned out to be both useful and functional when more research is done. In any case, the appendix (and vestigial structures in general), as promoted by the evolutionists in this thread, are not “proof for evolution.” Rather, they are evidence against the beliefs that the evolutionists here assume – incorrectly – that all of those opposed to evolution hold.


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Fallen
Member (Idle past 2046 days)
Posts: 38
Joined: 08-02-2007


Message 30 of 34 (418627)
08-29-2007 11:45 AM


My apologies to iceage and Coragyps for not addressing your posts specifically. I felt that addressing the ideas and assumptions behind the vestigial organs issue would lead to a cleaner, less time consuming discussion that talking about a lot of individual organs. If you feel that the issues that you brought up are not addressed adequately, please explain how and I will try to respond.

chiroptera writes:

Sure. That's the only way evidence can be used against an idea -- you need particulars in order to figure out what you should see in the world around us, and then to check whether the evidence supports or refutes those particulars. It isn't evidence against something vague like someone, somewhere, did something -- no evidence can refute something so vague. That is why creationism isn't science. Creationists refuse to pin themselves down to definite specifics that can be tested.

While it certainly is true that the mere proposition of an Intelligent Designer pins no details, that isn’t what Intelligent Design is about. Intelligent Design is a scientific research program dedicated to finding and analyzing signs of Intelligence like Behe’s irreducible complexity or Dembski’s complex, specified information. As a result, Intelligent Design is falsifiable/testable, since one has only to demonstrate that the signs of intelligence that Intelligent Design is based on can be explained by natural causes in order to falsify it. Many arguments using scientific evidence have been made against Intelligent Design, although the ones that I have seen are also refuted by scientific evidence.

Also, for the sake of accuracy, please don’t associate me with creationists, creationist theology, or creation science, as I am an Intelligent Design advocate with several beliefs that tend to get me into arguments with creationists when discussions like this come up.

If my understanding is correct, staying on topic is an important issue on this forum. Would you mind moving this discussion to a more appropriate topic so that this thread stays clean and simple?

Oh, but it is. Do you know what evidence is in science? One makes predictions based on one's theory, and then checks to see whether those predictions are observed. If the predicted phenomena are observed, then that counts as evidence in favor of the theory. If the predicted phenomena aren't observed, then we have a potential falsification.

Once common descent is recognized and once the phylogenic tree is more or less worked out to some degree, then one can make definite predictions about vestigial organs and see if one observes the predicted phenomena.

The problem is that evolution makes predictions in both directions and anywhere in between. Any number of vestigials (or complete lack of vestigials) can be explained as being due to the randomness of mutation and uncertainties about what selective pressures were at work. As result, nothing is really proved since the evidence would be accommodated regardless of what is actually found.

Also, these vestigial organs should be similar to organs that had a function in a recent ancestor. We shouldn't, for example, see frogs with vestigial wings -- frog ancestors didn't have wings. It is possible that some birds would have vestigial wings (and they do!), it is possible that some bats would have vestigial wings (which none do, as far as I know), but no frog should have vestigial wings. If a frog with vestigial wings were found in nature, that would be a problem for evolution.

If we found a frog with vestigial wings, people would see it as an organ “on its way in” rather than “on its way out,” and possibly even use it as further evidence for evolution. For example, flying fish have wings, but that isn’t considered to be evidence against evolution, in spite of the fact that they clearly have no ancestors with better wings.

This makes no sense for God creating the world ex nihilo unless we postulate that God wasn't so smart, and that he was forced to work within a budget. But most creationists assume that God is omnipotent and omniscient, so these limitations wouldn't apply. God is omniscient, so he already knows all the possible designs that he could use; he's omnipotent so he can make them come into being. It wouldn't be dumb for an omniscient, omnipotent God to make every creature with radically different designs. That fact that the number of designs is limited seems to be evidence that God isn't as omniscient or as omnipotent as his followers would have us believe…

This is why the argument is fundamentally a theological attack on creationism, not a scientific proof of evolution or evaluation of Intelligent Design. When the rubber hits the road, your argument is made up of your theological beliefs about how a designer would design things and using them when arguing against what you assume I have to believe if I accept an all-powerful designer. In other words, this piece of evidence is only counted in favor of evolution if you have a very specific set of theological beliefs. That is negative theology, not science, no matter how good a reason you have for your beliefs.

Setting that issue aside, I happen to disagree with your beliefs about how an all-powerful designer would go about doing things. However, at this point I come to an interesting puzzle. If I point out that the reasons that similarities are explained by design, you can respond by pointing out what you view as lack of functionality. Alternately, if I point out why I think functionality isn’t an issue for ID, you can come back by talking about the similarity. As a result, I think there are really two arguments here, functionality and similarity. In order to avoid this paradox, I think its best to address them both at once in the same place and explain all at once why dysfunctional similarities is not a good argument against ID. Here goes:

1. Functionality.
The first thing you need to realize is that most designers have more than one goal and that different designers have different goals. Basically, designing something is all about trade-offs (constrained optimalization) so that you can meet conflicting goals as well as possible. For example, making a car that can two hundred miles an hour probably isn’t a good idea if that means having a fuel efficiency measured in gallons per mile. In this case, efficiency would be balanced with speed. The problem with your argument is that you are assuming that an all-powerful designer would have only one goal for all of his designs: maximum fitness (defined in the evolutionary way).

First, we have no way of knowing the goals and intentions of the designer of life on earth, so any assumption about them is just that: an assumption. There is simply no evidence on this point, which is why ID theory doesn’t comment on it. That part of your argument is a version of the logical fallacy of begging the question – assuming a point within your argument that you are trying to demonstrate with your argument.

Second, maximum fitness makes no sense in the real world. Ecosystems can exist only because different organisms have different levels of fitness in different circumstances. For example, my favorite ecosystem is the intertidal zone. (the area between high tide and low tide) Different organisms do better when exposed to different amounts of air, sunlight, etc. and, in some places, are lined up according to their fitness in a particular area of the tidal zone. This creates a complex, fascinating ecosystem. But what if there was one organism did the best in all areas of the tidal zone? Simply put, it would dominate and then die out from lack of resources once all of the other organisms died off. Although the individual organism would have a much better design by your definition, the overall ecosystem design would suffer greatly from the imbalance. It would be like a baseball team that always hit home runs. Although it might be interesting for a little while, in the end the game would be a lot more fun with balanced competition.

The above points assume that the original design had at least some functionality. This is a reasonable assumption even if we don’t know of a function currently simply because we have often found functions for apparently functionless designs, and we also know that designs often become corrupted and lose function after being designed.

2. Similarities
I explained in my first post that all of the available evidence that we have about designers seems to indicate that they often use the same designs twice, or modify them for re-use. The main argument Chiroptera seems to have is that the current evidence is corrupted because it all comes from designers that have restraints (humans). Essentially, because engineers have limits to their time, money, and creativity, Chiroptera thinks they cannot be compared with an all-powerful designer, like the God of the Christian tradition, which his argument attacks. According to him, an all powerful being would by default have to create a more radically diverse array of designs than what scientists observe in our world.

The two key assumptions in this argument are 1) the “default” is complete diversity of designs without any similarities and 2) nothing other than lack of creativity or resources prevents designers from reaching the default.

I disagree with both assumptions. We know for a fact that designers, when possible, use the design that best meets their goals. Well, what happens when the designer has similar sets of goals in two different organisms? Simply put, the only logical thing to do within the parameters of good design, even when the designer is all powerful, is to use a similar design when you have a similar set of goals. This concept is well documented among almost all human made designs as well. The design that best meets the requirements is the one that is accepted, not the one that is most different from other designs.

There is also the fact that there isn’t an infinite number of “best” designs, or even designs period. Its possible that lack of total available designs rather than lack creativity could be a reason for not using completely different designs in all circumstances. Adding to this is the fact designs outside of our observation are possible, thus potentially increasing the total size of the pool of designs used.

Edited by Prodi, : typos/headings


Replies to this message:
 Message 31 by PaulK, posted 08-29-2007 12:15 PM Fallen has not yet responded
 Message 32 by molbiogirl, posted 08-29-2007 3:08 PM Fallen has not yet responded
 Message 33 by Chiroptera, posted 08-29-2007 4:15 PM Fallen has not yet responded
 Message 34 by iceage, posted 08-29-2007 4:55 PM Fallen has not yet responded

  
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