Criticizing neo-Darwinism

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 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.

This is a response to Message 97 by Parasomnium. 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. Agreed so far. 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. 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. 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.

I thought I did that. Apparently Para thought so to, and has responded. I will continue that debate.

Probably correct. However, this debate isn't about evolution. It is about the adequacy of the neo-Darwinian account of evolution. 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. 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.

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. That's one of the over-simplifications made by the model.

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. 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. 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? 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. The problem is that the change is described as optimizing what is already there, rather than as introducing novelty. 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.---------- It predicts punctuated equilibria as a significant mode of speciation. It predicts that novelty will arise.

From my perspective, selection is primarily of individuals. It is a species (or a population) that evolves.

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.

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.

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. 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. 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.

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. Quite right.

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). 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.

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.

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. 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.

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.