Hello, Springer.
quote:
Your hypothesis sounds reasonable, but I'm looking for evidence that it's actually possible.
At the risk of being suspended for endlessly repeating myself, I will post my little description of the theory of evolution. Do you want evidence that it is possible? The following is a very brief description of the theory of evolution. The items that I have labelled as fact are observed, verified facts; as long as the items labelled conclusions logically follow, then the items labelled as facts count as evidence that evolution is actually possible:
1. Fact: Most breeding organisms produce more offspring than is necessary to replace themselves.
2. Fact: The population of most species are not increasing.
3. Conclusion: Most individuals must die before reproducing.
4. Fact: Many of the physical traits of individual organisms are hereditary.
5. Fact: Some traits make an organism more likely to survive and reproduce, while others make an organism less likely to survive and reproduce.
6. Conclusion: From 3, 4, and 5 we can conclude that organisms with the traits that make them more likely to survive and reproduce will produce offspring with those traits, while organisms with traits that make them less likely to survive and reproduce will leave few or no offspring with those traits.
7. Conclusion: A corollary of 6 is that as generations pass, the number of organisms with "good" traits will increase, while the number of organisms with "bad" traits will decrease, until eventually all individuals in the species will have the "good" trait and the "bad" trait will disappear altogether.
8. Fact: New heritable traits, usually subtle, occasionally appear.
9. Fact: These new traits do not appear in any predictable pattern; these traits can appear in any body part or instinctual behavior; furthermore, some of these traits are helpful to an organism's survival, and others are detrimental.
10. Conclusion: From 7, 8 and 9 we can conclude that a species will slowly "improve" with time, as new helpful traits appear and as the organisms with these traits are better able to survive and produce offspring with these traits.
11. Fact: There is no mechanism that is known to prevent these small, incremental changes from adding up, over time, to large changes; furthermore, there very few (if any) physical organs and instinctual behaviors in any species that do not appear in simpler versions in other species.
12. Conclusion: From 10 and 11 we conclude that there is nothing that will prevent very simple, primitive living species from producing the complex species that we see around us.
13. Fact: Occassionally separate populations of a species will become physically isolated from one another and cannot interbreed.
14. Conclusion: From 9 and 13 we conclude that these populations will evolve independently; from 12 we conclude that these will become different species.
15. Conclusion: From several interations of 14, we conclude that several species can have a common ancestor.
Now, I have given reasons to believe that evolution is possible. Do you dispute any of the facts that I have stated? Do you disagree with any of the conclusions that I have deduced? If so, which ones and why? If not, then why do you not agree that evolution is possible?
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Now that we see that evolution is possible, let us try to decide whether there is evidence that it has actually occurred. How does science work? We use our theory to make predictions, predictions that should be observed if the theory were true, and then see if we observe the predictions.
If evolution were true, then we should see that the species can be placed in a
nested hierarchical pattern. This is because species that share a recent common ancestor should be very, very similar, species that share a slightly more distant ancestor should be similar but not as similar, species that only share a very, very distant ancestor should exhibit very few significant similarities.
Now, there isn't any other process that would predict this type of pattern. So, if we observe that the species fall into a nested hierarchical pattern that counts as confirmation of evolution; if no nested hierarchy is observed that counts as a falsification. This is not simply a word game; this is how science works, and this is how every single theory in every single field of science is tested.
What do we observe? Linnaeus himself, long before Darwin proposed his theories, noted that the species do fit a hierarchical pattern. Thus, the hierarchical classification confirms the theory of evolution. This is only one piece of evidence, of course, but any evidence counts.
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quote:
It equally fits a model of intellligent design.
I am afraid that you do not understand the point. It is true that an intelligent designer could have created the species with this pattern, but as I pointed out in another thread she need not have. If you try to classify any human-created object, like watches, you would not get a unique nested hierarchy. The actual pattern would depend on which characteristics were used to classify watches, and in which order they were chosen. An intelligent designer could have mixed and matched characteristics, to give snakes with feathers, birds with mammary glands, and so forth. There is no reason to expect
a priori how a designer would have made her designs. If intelligent design were true, there is no reason to expect a nested hierarchy as opposed to any other pattern. On the other hand, if evolution and common descent were true, then there
must be a hierarchical pattern. It cannot be avoided. And we do see a nested hierarchy. So we consider this evidence for evolution; again, this is not sophistry -- this is how any scientific theory is tested.
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Now let us examine the fossil record. The fossil record is not necessary for the theory of evolution; there is plenty of
other evidence for common descent. However, the fossil record has spectacular evidence in favor of evolution; futhermore, the evidence is so spectacular, that it makes an intelligent designer look quite odd.
Take whales. In the hierarchical classification, whales are definitely mammals. Therefore, according the theory of common descent, whales must have evolved from land mammals. Therefore, according to the theory of evolution, there used to exist, at various times, animals that showed characteristics that were in-between those of land mammals and modern whales, the so-called "transitional species". The question is now, did these species actually exist? It turns out that, indeed, there used to be creatures that had characteristics
in between those of ancient land mammals and modern whales.
Now, these species did not have to exist. There is no reason aside from the theory of evolution to expect them. But the theory of evolution states that they must have existed. And, in fact, they did exist! And so, each of these species counts as confirmation of the theory of evolution.
Of course, an intelligent designer might have created these species as well. But why? More to the point, why did she create so many "transitionals" that are predicted by the theory of evolution? Why did she create a series of
bipedal apes that bridge the gap between humans and non-human apes? Why did she create so many creatures that were neither fish nor tetrapod (four legged animal), but instead show
intermediate characteristics between fish and ancient tetrapods?
A more interesting question, is why is there no evidence of creatures that do not fit the evolutionary pattern? According to the theory of evolution, whales
must have evolved from earlier mammals. They
could not have evolved directly from fish. So according to the theory of evolution, there should be no species that are intermediate between fish and whales. Yet the intelligent designer, who created terrestrial mammal/whale "transitionals" could have created fish/whale transitionals. She could have created insect/rat transitionals. She chould have created bird/bat transitionals. Yet we see no evidence that these types of species ever existed. It appears that the intelligent designer only created species that confirm the theory of evolution. Why would she do such a thing?
It is a matter of Occam's Razor here. Why would one prefer to believe that a creator created species that appear to have evolved rather than believe that evolution has actually occurred? That is why the concept of intelligent designer is not accepted in biology; evolution, without a invoking a designer, not only explains what is observed, but correctly [i]predicts[/url] things that are observed. The concept of a designer, on the other hand, that created the appearance of evolution begins to strain credulity. One could believe in it, I suppose, if that is what one wishes; I don't see the point, however. Why not accept the evidence as it stands?
"Intellectually, scientifically, even artistically, fundamentalism -- biblical literalism -- is a road to nowhere, because it insists on fidelity to revealed truths that are not true." -- Katha Pollitt
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