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« on: August 28, 2006, 09:35:15 AM »
There seem to be a number of Creationists/IDists around here, so I thought maybe we could have a debate on evolution to distract from the much-less-relevant-in-the-modern-world debate on RE vs. FE.
As you all probably know, I am an atheist and thoroughly believe in common descent via evolution. The evidence supporting it is vast;
-Despite Creationist claims, there are thousands upon thousands of transitional fossils. In 1972, there were 4,000 hominid fossils alone, nevermind all the other transitions; and the number has certainly vastly increased in the last 34 years. Creationists attempt to explain away these fossils by claiming that they are not truly transitional- for example, Archaeopteryx is really either fully bird or fully dinosaur, not in-between; yet if Archaeopteyx is so clearly one or the other, why can Creationists not agree on which group it belongs to? The same goes for all other transitionals; Creationists completely disagree with each other about which group these supposedly 'clearly one or the other' fossils belong to.
-Most of the so-called bars to evolution are based on misunderstandings of how evolution actually works. Creationists will say, "A fish never gives birth to a dog, so evolution doesn't work" (no, that's not a strawman example; I have had people honestly say that to me). What such arguments fail to realize is that evolution is very, very gradual, and that there are not such distinct lines between taxa. If a fish gave birth to dog, it would be evidence of some very strange phenomenon that had nothing to do with evolution. Evolution does not require any more change per generation than the difference between you and your parents. Over three billion years, such small changes add up to a very large amount of change; much more change than the difference between a fish and a dog. Of course a fish will never give birth to a dog; but a fish will give birth to something slightly different, over many generations, until you have something that is distinctly not a fish. The lines between taxa are blurry. Though a fish will never give birth to a dog, there was a time when something just-barely not a dog gave birth to something that was a dog; but that just-barely not a dog would be the same species as its offspring- as I said, the lines between taxa are fluid.
-Another supposed block to evolution is Michael Behe's concept of "irreducible complexity", which states that some living systems need all of their parts to be present to work at all, meaning they could not have evolved gradually. However, while these systems could not have evolved piece-by-piece, as all the pieces are needed for the system to convey selectable benefit, there are other ways for such systems to evolve. The first is co-option, where already-working systems are incorporated into a new system, and then their function is changed. The second is 'scaffolding': imagine you are building an arch out of stone blocks. Stone arches hold themselves up, but if you remove any piece the whole structure falls down. So to build one, you would make a scaffold underneath the arch to hold it up until construction is complete. Similarly, evolution might create a system with lots of unnecessary, redundant parts- such a system would not be irreducibly complex- then once the system was 'built', natural selection would remove the redundant parts so that every part left was necessary for the system to work at all- rendering the system irreducibly complex.
-Another block is supposedly a result of the Second Law of Thermodynamics. A common misconception is that the 2nd Law states that order cannot arise from disorder, therefore evolution could not have happened. However, order arises from disorder all the time. Complex, ordered weather patterns such as hurricanes arise from chaotic winds; snowflakes arise from chaotic frozen water droplets. All that is required is the input of new energy- and the sun provides lots of new energy. I have heard Creationists (notably Duane Gish) state that the input of new energy is not enough, that there must be energy-converting-and-directing mechanisms; yet that is exactly what the chemical synthesis engines (photosynthesis, for example) inside living cells are: energy-converting-and-directing mechanisms! Apparently Duane Gish has never heard of photosynthesis.
Now, anyone want to argue this?