"Assumptions" is a magic word

juvenissun said:

For example, a species of E. Coli is trained to eat plastics ONLY. Now take the plastics away from that E. Coli, would it still remember how to eat plastics over a few (tens of ?) generations? Would the plastics-starved E.Coli start to search for a new diet or would it go back to the old diet?

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Just came across this recent study of why evolution does not reverse itself.


http://www.nytimes.com/2009/09/29/science/29evol.html?_r=1&scp=2&sq=evolution&st=cse

gluadys said:

Just came across this recent study of why evolution does not reverse itself.


http://www.nytimes.com/2009/09/29/science/29evol.html?_r=1&scp=2&sq=evolution&st=cse

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Thanks.

I am sort of busy. But I will tell you what I think at later time.

philadiddle said:

Ok, it's a later time now.

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I understand that a life form is not likely to change "back" to what it was because the environment could never reverse back to what it was in 100%. (if it could, then I do not see the reason why not.). There are many variables work in the environment. It is unlikely for all of them to change back at the same time and on the same pace.

But, The change of variables in the environment has a limited range within the given time (so we do not compare paleocene with pleistocene). We may call the range of change as the "normal" environment. A life changes in a normal environment, then it should also have a limited range of the change. Let's say it is called a "normal" change. An example could be like trilobite A changed to trilobite B.

But, the exciting thing in the evolution account is that life form may change in any way but "normal". For example, the environment might change "normally" during the time when fish changed to amphibian. That means the life made an abnormal change in a normal environment. This kind of change is very unlikely.

If you stop feeding the plastic-eating e-coli plastics but normal food, then there are three options: it dies, it goes back to what it was, and it changed to a third type of e-coli. If the environment is tightly controlled so that only one variable is changed back and forth, I believe the life form will either die or change back and forth. The third option will not happen.

The newly isolated population will not revert to earlier forms; those genes have been bred out of the pool. Those that cannot survive will die off. Those that can survive will tend to survive and pass on those beneficial genes to succeeding generations. A new, restricted gene pool will arise out of the survivors and it may look significantly different from its ancestors. There are no new genes, but fewer genes. This is how variations in population come to look like evolution, but are really devolution.

"Survival of the fittest" is a tautology. Populations seek stasis, not change.

jackmt said:

The newly isolated population will not revert to earlier forms; those genes have been bred out of the pool. Those that cannot survive will die off. Those that can survive will tend to survive and pass on those beneficial genes to succeeding generations. A new, restricted gene pool will arise out of the survivors and it may look significantly different from its ancestors. There are no new genes, but fewer genes.

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Strictly speaking there are fewer alleles, not fewer genes. The new isolated population doesn't really lose genes, but where the gene pool of the ancestral population may have contained 10 variations of a particular gene, the isolated population has just 1 or 2 and not necessarily the alleles that were most common in the ancestral gene pool.

But this is also a temporary situation as new alleles will also emerge in the new population. So there is no true restriction on the new gene pool. It is just as free to develop variations as the ancestral gene pool was. And in its new ecological niche, the variations that survive will be different from those that were favored in the ancestral gene pool thus reinforcing the difference between the older and newer populations.

My key idea is this: The change of environment is limited in range. So the change of life form should also be limited as long as the new form is good enough to deal with the new environment (forward or backward). Any excess degree of change is NOT NEEDED.

So, an obvious example is that some of the dinosaurs have no reason to become so large. And fish had no reason to come up to land.

philadiddle said:

Creationists say "Assumptions" like how magicians say "Abracadabra." When a lot of research, experiments, and empirical evidence are presented, the creationists say "assumptions" to magically make it all go away. Why argue the actual data when you can convince your audience it is wrong with one simple word? I've been noticing this more and more as I discuss science and Christianity on other forums and read some creationist literature. It's always "they are basing it on assumptions" or "take away their assumptions and it all falls apart".

"Presuppositions" is another one.

So annoying.

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A prior (without prior) assumptions are an attempt to identify the substantive element that transcends all reality. A creationist by the name of Aristotle examined this in his book on Metaphysics and another Creationist by the name of St. Thomas Aquinas elaborated on this in his metaphysics of Genesis. Immanuel Kant described these a priori assumptions in the opening lines of his, 'The Critique of Pure Reason':


I don't want you to take this wrong since you have made such a determined effort to be civil but you really shouldn't be throwing words around like this so carelessly. These are not Creationist words from some bird bath, knee jerk rationalization, it's pure, undiluted philosophical epistemology, which by the way, is the essence of scientific thought.

Don't play around with things you don't understand, or at least, take a cursory glance at the meaning behind them.

Grace and peace,
Mark

gluadys said:

Thinking through the basics of evolutionary theory, I am finding it remarkably difficult to come up with any assumptions. The one I can think of is not an assumption of evolutionary theory, but of all science; namely, that if the observations our theory predicts we should be able to make are in fact observed, it is likely that our theory provides a correct model of nature.

Darwin began with a couple of observations and a couple of inferences and came to a conclusion. Most of evolutionary theory would seem to consist of the same ingredients.

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the theory of evolution has NEVER been observed. the excuse of course is it takes to long. though its been happening for ever in their thinking. So why would there not be a species on the brink of changing classes. like going from being a reptile to being a amphibian for which there only needs to be like one or two mutations to change it over to a amphibian. the only predictions involved are of evolution and dont actualy show the thoery except when assumption is added.

gluadys said:

Thinking through the basics of evolutionary theory, I am finding it remarkably difficult to come up with any assumptions. The one I can think of is not an assumption of evolutionary theory, but of all science; namely, that if the observations our theory predicts we should be able to make are in fact observed, it is likely that our theory provides a correct model of nature.

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Define 'evolution theory' without reference to Darwinian naturalistic assumptions and you might have something there.

Darwin began with a couple of observations and a couple of inferences and came to a conclusion. Most of evolutionary theory would seem to consist of the same ingredients.

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Darwin made his case clear in the preface of On the Origin of Species, he was agruing against special creation in favor of natural selection. Most of evolutionary theory is the same transcendent naturalistic assumption applied to natural history in all its forms and features. There is no other way of describing it except as an 'a priori' assumption, unless you want to dismiss it as an untested hypothesis.