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Author Topic:   Criticizing neo-Darwinism
nwr
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Posts: 6445
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.0


Message 1 of 309 (296949)
03-20-2006 8:58 PM


In Message 92 I expressed my opinion that the traditional neo-Darwinist account of evolution is one that many people, not just creationists, find implausible. Parasomnium has answered this in Message 97 (same thread). This current topic is intended to provide a place where I can continue this debate with Parasomnium and others, since it would take the earlier thread off topic if continued there.
Parasomnium nicely summarized the neo-Darwinian position I was criticizing, with
Not wishing to blow my own horn, I must say I find nothing more plausible than the fact that, if hereditary information randomly changes, which is a fact, and if the environment can only sustain the better adapted, which is also a fact, then the adaptive changes are preserved at the expense of the less well adapted. A long cumulation of these changes naturally leads to extremely well adapted, very complex structures.
That's the account I find problematic. It is roughly the same as the "Selfish Gene" account popularized by Dawkins. While I find that account problematic, I do not question that evolution occurred. I just want a better formulation than that of traditional neo-Darwinism.
This topic is for discussing the problems with that particular neo-Darwinian account. It is not for arguing whether evolution happened or is happening.

Replies to this message:
 Message 4 by crashfrog, posted 03-20-2006 10:13 PM nwr has replied
 Message 6 by RAZD, posted 03-20-2006 10:48 PM nwr has replied
 Message 19 by Brad McFall, posted 03-21-2006 10:28 PM nwr has seen this message but not replied
 Message 101 by MartinV, posted 08-29-2006 4:25 AM nwr has seen this message but not replied
 Message 182 by RAZD, posted 06-05-2007 4:50 PM nwr has seen this message but not replied
 Message 209 by Elmer, posted 11-14-2007 3:55 PM nwr has seen this message but not replied

  
nwr
Member
Posts: 6445
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.0


Message 3 of 309 (296964)
03-20-2006 10:08 PM


This is a response to Message 97 by Parasomnium.
Parasomnium writes:
The mathematics of evolution, especially the mathematics of the probabilities involved, are often misunderstood.
I agree. However, mathematicians tend to understand the mathematics better than non-mathematicians. Fred Hoyle was no slouch at mathematics, and he found fault with the neo-Darwinist account.
Not wishing to blow my own horn, I must say I find nothing more plausible than the fact that, if hereditary information randomly changes, which is a fact, ...
Agreed so far.
..., and if the environment can only sustain the better adapted, which is also a fact, then the adaptive changes are preserved at the expense of the less well adapted.
That's where the argument begins to run into problems. The expression "better adapted" is itself a little vague.
There is a saying "The early bird gets the worm." But it wasn't a matter of being less well adapted that caused the worm to be eaten. It was just bad luck that the bird happened to be around at that time. There are many contingencies of life that affect whether an individual survives to reproduce. Differences in how well adapted are only part of the story. Sure, there might be a statistical filtering effect. But for small differences in how well adapted, this filtering is a weak effect in a sea of contingencies. Any filtering would be very slow, and in my opinion it would be too slow to account for biological diversity.
It could be that a slightly deleterious gene occurs on the same chromosome as a slighly beneficial gene. Since they are on the same chromosome, they tend to be inherited together. The disadvantages of the one are offset by the benefits of the other, so there is no net filtering effect. Agreed, the two genes can be separated during a crossover. But if they are close together on the same chromosome, then the probability that a crossover will divide them is relatively small. To consider the filtering in this case, you have to look not at the time between generations, but at the time between crossover events that divide between the two genes. The rate of filtering would be extremely slow.
A long cumulation of these changes naturally leads to extremely well adapted, very complex structures.
That's where it becomes downright implausible. The neo-Darwinistic account is one of gradual change. The arguments about irreducible complexity arise because gradual change does not plausibly lead to very complex structures. The biology shows how complex structures can arise, but the gradualism of the neo-Darwinist model seems to argue against it.
I'll toss in another problem. According to neo-Darwinism, evolution advances by adaptation. However, it seems to me that a species cannot exist unless it is already adapted. And becoming over-adapted would only result in exponential growth of a species until it destroyed its own habitat. The only way I can see a species being mal-adapted, is when some environmental change destroys the environment to which a species was previously adapted. Granted, such changes can and do occur, some caused by other evolutionary changes in the biosphere (what Dawkins refers to as an arms race). But I am skeptical that such environmental change can account for all of the adaptation that would be needed to explain the degree of biological diversity and complexity that we find.
Being science-minded, they will certainly not resist your theory if it stands up to rigorous scientific tests and explains things better than the theory of evolution does.
My theory doesn't change the biology at all, so it should stand up to the biological testing. And it would still be a theory of evolution, just not the neo-Darwinist version. But I think you underestimate the resistance to change.

Replies to this message:
 Message 5 by NosyNed, posted 03-20-2006 10:36 PM nwr has replied
 Message 7 by Parasomnium, posted 03-21-2006 5:45 AM nwr has replied
 Message 8 by Chiroptera, posted 03-21-2006 9:09 AM nwr has seen this message but not replied
 Message 130 by Allopatrik, posted 03-05-2007 2:02 PM nwr has seen this message but not replied
 Message 279 by Bolder-dash, posted 11-30-2010 11:37 AM nwr has replied
 Message 306 by herebedragons, posted 12-20-2010 11:01 AM nwr has replied

  
nwr
Member
Posts: 6445
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.0


Message 10 of 309 (297078)
03-21-2006 1:22 PM
Reply to: Message 4 by crashfrog
03-20-2006 10:13 PM


Perhaps it would help if you were to elucidate the ways that you find Para's account, which is marvelously simple and obviously correct, to be uncompelling to you.
I thought I did that. Apparently Para thought so to, and has responded. I will continue that debate.

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nwr
Member
Posts: 6445
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.0


Message 11 of 309 (297083)
03-21-2006 2:00 PM
Reply to: Message 5 by NosyNed
03-20-2006 10:36 PM


Re: Gradualism
I'm not sure that there as ever been utter gradualism.
Probably correct. However, this debate isn't about evolution. It is about the adequacy of the neo-Darwinian account of evolution.
The problems introduced by IC have NOTHING to do with gradualism as far as pace goes. They do have to do with "step size". However, they do not deal with pathways through evolutionary space.
They have to do with whether a sequence of steps is required, such that intermediate steps should be impossible or very unlikely due to negative selection against them. To me, this does seem to be a problem in the neo-Darwinian account, although I don't see a problem in the biology. If I'm right, that would argue that there is a problem with neo-Darwinism.
The question is: Why are you skeptical?
Remember that my comment was in the context of an assumed neo-Darwinian model.
As is often the case with mathematical modelling, the model doesn't fully match reality. IMO the mismatch is serious, and the model is not adequate for the job.

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Replies to this message:
 Message 17 by Wounded King, posted 03-21-2006 5:40 PM nwr has replied

  
nwr
Member
Posts: 6445
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.0


Message 12 of 309 (297085)
03-21-2006 2:06 PM
Reply to: Message 6 by RAZD
03-20-2006 10:48 PM


Re: muddled thoughts.
No amount of genetic "selfishness" allowed large dinosaurs to survive the KT extinction event.
In my opinion, neodarwinism explain extinction rather well. But it doesn't do so well at accounting for novelty. You can account for the novelty by appealing to the biology. But if neodarwinism were a good model, then you should not have to keep appealing to the biology to help the model over its weak points.
The problem I have is that genes don't get selected on their own, that they are necessarily {groups\sets\associations\clubs}.
That's one of the over-simplifications made by the model.

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 Message 6 by RAZD, posted 03-20-2006 10:48 PM RAZD has replied

Replies to this message:
 Message 15 by crashfrog, posted 03-21-2006 3:47 PM nwr has replied
 Message 62 by RAZD, posted 03-26-2006 8:10 PM nwr has replied

  
nwr
Member
Posts: 6445
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.0


Message 13 of 309 (297090)
03-21-2006 2:54 PM
Reply to: Message 7 by Parasomnium
03-21-2006 5:45 AM


Re: Defending neo-Darwinism
Well, apart from stating the obvious about mathematicians, your mentioning Fred Hoyle doesn't do your argument much good either.
I'm well aware that he is not very popular among evolutionists. Still, he did go to some effort to work out the implications of neo-Darwinist assumptions.
His equally fervent opposition against chemical evolution, culminating in his comparison of the random emergence of even the simplest cell to the likelihood that "a tornado sweeping through a junk-yard might assemble a Boeing 747 from the materials therein", is a prime example of the misunderstanding of the probabilities involved, which I mentioned earlier.
Hoyle did have a way with rhetoric. As far as I know, that comment was based on the neo-Darwinian model, rather than on what is observed biologically. To show he misunderstood the probabilities, you would have to show that his mathematical analysis was wrong. An appeal to empirically observed probabilities would tend to support Hoyle's conclusion that neo-Darwinism provides a poor account.
Any net filtering effect will inevitably lead to diversification, it just remains to be seen how fast it proceeds.
This is what is not obvious to me (assuming the neo-Darwinian model).
The model is usually described as one of optimizing the degree of adaptation. Supposedly the early earth was inhabited only by algae. So why are we here? Why does the biosphere not consist only of optimally adapted algae?
Since you question the adequacy of the speed with which it takes place, it's up to you to show that it's too slow if you do not wish to be accused of personal incredulity.
Perhaps my wording was a bit confusing. I don't see that speeding up the filtering would help. The model still does not adequately explain novelty.
You will have to explain this in more detail to convince me. How does gradual change not plausibly lead to very complex structures, and how does the gradualism of the neo-Darwinist model seem to argue against it?
The problem is that the change is described as optimizing what is already there, rather than as introducing novelty.
You seem to assume that being adapted is an all-or-nothing quality. Although I am sure you don't mean it that way, you might want to reassure me.
Sloppy wording. In my preferred alternative theory, I think of degree of adaptation as a numeric value. Roughly, it is the ratio of the expected population size of the next generation to the population size of the current generation (where "expected" is in the probabalistic sense).
In practical terms, a degree of adaptation significantly less than 1 would indicate a species on the path to extinction. A degree of adaptivity greater than 1 would lead to exponential growth, so could not be long sustained. Thus a degree of adaptation that hovers around 1 is what would be needed for a species to be considered well adapted.
----------
If your theory is a theory of evolution, it should not just stand "biological testing", whatever that means, but it should stand evolutionary testing, i.e. it should make evolutionary predictions that could be verified.
It predicts punctuated equilibria as a significant mode of speciation. It predicts that novelty will arise.

This message is a reply to:
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nwr
Member
Posts: 6445
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.0


Message 14 of 309 (297093)
03-21-2006 2:59 PM
Reply to: Message 9 by EZscience
03-21-2006 10:13 AM


Re: Units of selection and units of evolution
I think this discussion might benefit from everyone specifying the units of evolution they are referring to when they talk about evolutionary process.
From my perspective, selection is primarily of individuals. It is a species (or a population) that evolves.

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nwr
Member
Posts: 6445
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.0


Message 16 of 309 (297097)
03-21-2006 4:09 PM
Reply to: Message 15 by crashfrog
03-21-2006 3:47 PM


Re: muddled thoughts.
What would be the basis of an evolutionary theory besides the biology of the organisms that are evolving?
This isn't a discussion of the biological basis for evolution. It is a discussion of whether the neoDarwinian account, as quoted in Message 1 (from a post by Parasomnium) is an adequate model for ToE.
In case it wasn't already clear, let me restate that I am on the pro-evolution side of the house.

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Replies to this message:
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nwr
Member
Posts: 6445
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.0


Message 20 of 309 (297428)
03-22-2006 7:56 PM
Reply to: Message 17 by Wounded King
03-21-2006 5:40 PM


Re: Gradualism
Do you have any evidence that non-functional or detrimental intermediates are the standard pathway in neo-darwinian 'accounts'?
I don't know that there is such a "standard pathway". It is pretty much the definition of IC (irreducible complexity), that such a problem would exist for IC systems (see Message 102).
If such systems can evolve, but the neo-Darwinian account does not provide a plausible explanation, then there is a problem with that account.

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Replies to this message:
 Message 21 by Belfry, posted 03-22-2006 8:10 PM nwr has replied

  
nwr
Member
Posts: 6445
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.0


Message 22 of 309 (297445)
03-22-2006 8:58 PM
Reply to: Message 21 by Belfry
03-22-2006 8:10 PM


Re: Gradualism
Can you give any examples where this scenario exists?
I'm not a biologist, so I can only go on what I read.
As best I can tell, biologists have not denied that there are IC systems. However, they have shown that IC system can evolve.
Does neo-Darwinism really pose a problem for such system? Or am I misunderstanding it? You will have to decide that for yourself. It seems to me that neo-Darwinism is a bit too vague. It doesn't really give enough details on how the evolving would proceed. But excessive vagueness can also be a problem.
This "detrimental intermediate" thing is a classic creationist strawman, as you must know.
Yes, I'm aware of that. But creationists are not making this argument out of whole cloth. They are getting the idea from what seems to be the neo-Darwinist account as to how an IC system would have to evolve.
Also, are you being sincere with this thread, or are you messing with us?
I'm being sincere. But, to repeat, I am not arguing against evolution. I am arguing that neo-Darwinism is part of the problem. It describes evolution in a way that many non-scientific folk find implausible. If you had a better theory, one that made it more obvious to non-scientists that evolution is a near certainty, then creationism and ID would not be getting the support that it has.

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Replies to this message:
 Message 23 by Belfry, posted 03-22-2006 9:10 PM nwr has replied
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nwr
Member
Posts: 6445
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.0


Message 30 of 309 (297586)
03-23-2006 1:19 PM
Reply to: Message 29 by Brad McFall
03-23-2006 8:47 AM


Re: background reading?
I think it is CLEAR AND OBVIOUS what NWR means.
Thanks, Brad. However, reading the other responses in this thread, is is apparent that what I mean is neither clear nor obvious to most of the responders.
Dawkins is a neoDarwinist in the "contrary" sense.
Quite right.

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nwr
Member
Posts: 6445
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.0


Message 31 of 309 (297592)
03-23-2006 1:37 PM
Reply to: Message 28 by Brad McFall
03-23-2006 8:46 AM


Re: my muddled mind
Message 28, to which I am responding, might be one of the clearest posts that Brad has made (not counting really short ones such as Message 29).
The problem (in biology (keeping all CvE out for the moment, etc.)) is that bean bag Neo-Darwinisms do have all of this 'biology' that is not simply a version of Dawkinsoniansims as "heritibility." But as Waddington remarks (see the first thumbnail provided above) this is a "fudge factor."
Very well stated. And Waddington is clear on what "neo-Darwinism" ought to mean in his first paragraph (what he calls its strict sense). I'm not sure why this is confusing to other participants in the thread. This repeated need to call on biology for a fudge factor should be the indication that neo-Darwinism (strict sense) is not an adequate account of evolution.

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nwr
Member
Posts: 6445
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.0


Message 32 of 309 (297593)
03-23-2006 1:43 PM
Reply to: Message 23 by Belfry
03-22-2006 9:10 PM


Re: Gradualism
I am not aware of any "neo-Darwinist" account such as this. I think you need to show that such an account actually exists (other than as a creationist strawman) before you present it as a problem.
I am referring to what is summarized in the quote box of Message 1, as quoted from Parasomnium. This can be put into a mathematical form, allowing one to describe and and deductively analyze the evolving of the gene pool over time.

This message is a reply to:
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Replies to this message:
 Message 34 by Belfry, posted 03-23-2006 2:08 PM nwr has replied

  
nwr
Member
Posts: 6445
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.0


Message 33 of 309 (297594)
03-23-2006 1:54 PM
Reply to: Message 26 by Modulous
03-23-2006 8:22 AM


Re: my muddled mind
I'm still confused - Parasomnium was discussing a biological basis for evolution. He talked about heredity.
Heredity isn't the problem. That's included as part of the neo-Darwinian theory, in the form of the stochastic process whereby one derives the gene distribution of the next generation from the gene distribution of the current generation.
It doesn't make a lick of sense to me. Neodarwinism is an explanation for biological change. How does 'appealing to biology' present a problem for a biological theory, surely that is precisely what it should do?
In the strict sense, neo-Darwinism is an explanation for changes in the gene pool.
The general idea of using mathematical models in science, is that you feed data into the model. Then you make deductions purely from the model, without reference back to the real world source. This leads to predictions from the model. Finally, you interpret those predictions, in terms of how the model represents real world data.

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nwr
Member
Posts: 6445
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 5.0


Message 35 of 309 (297599)
03-23-2006 2:08 PM
Reply to: Message 27 by Belfry
03-23-2006 8:33 AM


Re: There is no "better" question, it was already in thread
For example, at one point (in Message 13) nwr suggests that his "preferred alternative theory" (apparently in contrast to neo-Darwinism) "predicts punctuated equilibria as a significant mode of speciation. It predicts that novelty will arise.". If neo-Darwinism, in nwr's thinking, excludes these concepts, then I don't know of any modern biologists who are neo-Darwinists. It is a concept built of straw.
This is an example of what randman might call "total evo dishonesty".
I'm sure it wasn't intentionally dishonest. But there is a huge flaw in the reasoning.
I used "predicts punctuated equilibria". You used "excludes" as the alternative to predicts. Those are not alternatives. A theory can fail to predict X, while also not excluding X. In fact it seems to me that neo-Darwinism neither predicts nor excludes punk-eek. It explains punk-eek only by means of appealing to reproductive isolation. That's an example of an appeal to the biology as a fudge factor. The statement of neo-Darwinism in Message 1 nowhere mentions reproductive isolation as a necessary or important requirement for evolution.

This message is a reply to:
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Replies to this message:
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