Posted by AF [AF] on November 28, 1999 at 16:56:32 {hcnmikA.Fk1EwaxRomAMdaOt1gg/Zk}:
In Reply to: *Examples of Speciation posted by Liberal Elder on November 28, 1999 at 10:51:44:
: In your analogy of continental drift is there not an assumption that whatever force is presently responsible for 1cm of annual continental drift has been present for each year of the last one billion years so as to produce a shift of 10,000 kilometers?
Not at all. Most geologists certainly assume that the forces that produce continental drift have not substantially changed during that time, but these forces - which are the presumed cause of continental drift - have nothing to do with the many observations that indicate that continental drift has occurred. Jan gave only the barest outline of the evidence, so I'll fill in with some details.
Jan said that it has been observed that continents drift at a certain rate, and that from that rate and the known age of continents geologists can do a simple calculation that shows that today's drift rate is pretty close to the average assumed drift rate over the last several hundred million years. Of course, there are actually many continents and many pieces of ocean floor that drift at rather different rates, ranging from ½ to 10 cm. per year. In each case that has been looked at, the present drift rate is consistent with the average over the lifetime of the drifting.
Since ocean floor generally expands at spreading centers known as mid-ocean ridges, a test of the constancy of drift rate is to measure the age of the rock composing the ocean floor from the mid-ocean ridge to the edge of a continent. Sure enough, such age measurements turn out to be consistent with the average drift rate. This has been done in the Atlantic and Pacific. The farther you get from the ridge, the older the rock.
A fine example is the age of ocean floor and various above-sea-level features from the Hawaiian Islands west-northwest to the island of Midway, and then north-northwest to the Kamchatka Peninsula. Ocean floor gets progressively older, reaching 200 million years (the oldest ocean floor known) at the point where Pacific Ocean floor dives under the Kamchatka Peninsula. The Hawaiian Islands have been built as the ocean floor drifts over a "hotspot", and so these island are progressively older the further west you go. The island chain becomes an underwater mountain chain at the western end of the Hawaiian Isalnds. At about Midway Island, the chain emerges, and then turns more northward. This underwater chain continues all the way to Kamchatka. The entire chain traces the 200 million year history of the Pacific Ocean floor drifting over the Hawaiian hotspot.
The Indian subcontinent began drifting northward towards Asia some 60 million years ago, at a very high rate. It collided with Asia some 20 million years ago and gradually formed the Himalayan Plateau along with huge mountain masses on either side of India, from Persia to China. And guess what? The age of the ocean floor along India's path is consistent with its high drift rate.
There are many other details that are best found by reading the geological literature. I hope that these examples give you a taste for what you can find.
: From my perspective these analogy does not seem particulary useful for the following reasons:
: 1. It would first be necessary to demonstrate that the conditions that are cuurently exerting these forces were present over each of the last one billion years.
The information I presented above, along with massive amounts in geological literature, indicates that continental drift rates are fairly constant. It's a small step to assume that the causes are also fairly constant. Geologists don't know for sure the exact causes, but have a good idea. They're involved with turbulent flow of magma and other internal material in the earth, and such systems are poorly understood theoretically. One needs far more massive supercomputers than now exist to properly model these phenomena in the detail necessary to show the precise mechanisms of continental drift. One also needs much more detailed information on the internal structure of the earth, but instrumentation to obtain this is now in development.
: 2. It would be important to know that counter forces in fact have not exerted themselves in the past.
The fact that intermediate seafloor ages show a progession is pretty good evidence.
: It may well be that geology has already sufficiently answered these issues, I really don't know.
I think it has. Given the above, what do you now think?
: When it comes to applying this kind of analogy to living organisms, I can see some other problems as well. There is nothing particulary stable or one directional about conditions on the earth. They appear to be in a perpetual state of change. The kinds of environmental change that may have prompted a species to adapt at one point in time seldom remain constant as in your analogy of continental drift over the course of one billion years.
It's true that the forces related to evolution are much more complex than those related to continental drift. That's why it has been so difficult to pinpoint cause and effect relationships in evolution. Much is speculative because the basic mechanisms are poorly understood. What is known solidly is that populations of organisms have evolved, and that huge numbers of old organisms have died out and huge numbers of new ones have appeared. It is satisfying for Christians and others to attribute these things to the creative powers of God. Whether this is so, or things have appeared entirely due to the operation of "atheistic evolution", I don't know, and it is not relevant to the facts that we've been discussing here.
: If your hope it to persuade open minded liberal Christians to seriously consider your position, I think that you will have to come up with something better than this.
The very best way for anyone to decide is to educate themselves in the sciences necessary to make their own determination. For a brief but detailed introduction to continental drift, you might look at my Flood writeup on Osarsif's website beginning with the section on plate tectonics.
: P.S. Your examples of speciation are very interesting and thought provoking. I would think that any open minded individual would have to concede that biological organisms have demonstrated the ability to change, perhaps even into new species or sub-species if your examples are in fact true and can be substantiated. This does not, however, prove that living things come from non-living material. That is a much greater leap and one that I would require very conclusive evidence to accept.
I understand your reticence perfectly, and I certainly don't claim to know the answers. However, one thing I have certainly learned in my studies of science: the argument from incredulity usually falls down. If you can accept that there is an all-knowing, all-powerful God that either has always existed, or came from nothing (what came before God?) then philosophically it's not much different from accepting that life came from non-life via mechanisms we do not yet understand.
AF