leroy wrote:leroy: Selectionism: we know that at least some “benefitial steps” require multiple independent and codependent mutations
Rumraket: No we don't.
leroy: well atleast Behe, Dragan, Morlan and I would disagree with you,
I thought you meant besides the example of chloroquine resistance. You are claiming to have found examples of adaptations that could not have evolved, right? Then showing an example of an adaptation that evolved seems rather self-defeating in my view.
That means adaptations that require multiple specific but necessary mutations where both (or more) of them are neutral, or even deleterious, but only when combined are beneficial,
in species that have too low population sizes to have "found" them.
leroy wrote:we know that at least some “benefitial steps” require multiple independent and codependent mutations, this is an uncontroversial fact,
We know that chloroquine resistance requires at least one neutral mutation, which if present will result in resistance if another particular mutation happens. This second mutation is then beneficial. And chloroquine resistance evolved.
The problem is that Michael Behe
originally declared that it required two simultaneously deleterious mutations, meaning that they would have been selected against individually, but only when in combination would the exhibit synergistic postitive epistasis. Had that been true, he would have had a point.
"Close your eyes and envision a pathway to a malaria parasite that has four mutations. The first mutation is deleterious, the second rescues the first and makes the parasite marginally chloroquine resistant. Subsequent steps are all beneficial by dint of either improving chloroquine resistance or of stabilizing the structure of the mutated PfCRT, which is required for malaria survival. Once a parasite can survive at least marginally in the presence of chloroquine, further mutations can be added one at a time (no longer two at a time) in each cycle of infection because the population size (1012) greatly exceeds the inverse of the mutation rate.
In the argot of chemical kinetics, getting beyond the deleterious mutation is the "rate-limiting step." After that hurdle is passed further mutations can be added singly -- the way Darwinists like -- and comparatively rapidly. Since they would be added rapidly, they would be difficult to detect in the wild." -
Michael Behe"If even one step in a long and relentlessly detailed evolutionary pathway is deleterious, then a Darwinian process is woefully impaired. If several steps in a row are deleterious, you can kiss the Darwinian explanation goodbye." -
Michael BeheHe then later changed the tune to claim that when it was found at least one of the required mutations for strong resistance to chloroquine resistance,
was neutral, this vindicated his prediction. That is just some historical background here that shows Michael Behe's tendency at historical revisionism.
Let me note here that
None of the mutations required for chloroquine resistance are deleterious. Now, it is still true that depending on the genetic background of the parasite (which mutations are already present), some pathways to chloroquine resistance requires two mutations to yield a single beneficial step. And Behe then says that IF a particular adaptation requires such two specific mutations to evolve, one or both of which on their own are neutral(or worse, deleterious), then this is the "edge" of evolution beyond which we should not generally expect Darwinian evolution to be able to move for species with smaller population sizes. Which is true, but a trivial statement. Nobody has claimed otherwise.
The issue is that only a single example of such an adaptation, which required two specific mutations a single of which is neutral, to evolve. But we don't know of any other such examples, and certainly not for any multicellular eukaryote.
And notice, though, that this is supposedly the "edge". Meaning such double-mutants could still evolve in organisms with huge population sizes, like bacteria, viruses and so on. It would become very interesting if an example could be found in multicellular eukaryotes like plants and animals.
leroy wrote:Rumraket wrote:And now your job is to go out in the world and find that there are many many more adaptations or functions in living organism that require multiple (two or more) of such individually useless, or deleterious (but only if combined beneficial), mutations to have evolved, than evolution could ever have been expected to produce.
It is all fine and well to come up with these hypothetical barriers to evolution. Finding actual examples of them in the real world is a different matter. So off you go, find me an adaptation or function that requires multiple specific simultaneous mutations to have evolved.
one wonders, why is it that atheist from this forum never what to carry their burden proof?
Because YOU are the one claiming to be in possesion of an argument that should cause us to doubt the veracity of the evidence that has already been collected. The evidence from the past history of life from comparative genetics, comparative anatomy, chronology of embryological developments, from the fossil record, from observations of molecular change in experiments, to observations of change of wild populations, from change due to domestic breeding and artificial selection and so on and so forth ad infinitum.
This is all evidence that evolution took place, that species share common descent, and that the process has been going on evolving new species, greater diversity, more complexity, more genetic information and so on for hundreds of thousands of independent lineages for billions of years.
Now you come along and say "oh but you see if there are these hypothetical barriers, then something else would have to have caused those particular things to evolve".
Yes, but ARE there these hypothetical barriers? Prove it. The burden is yours.
leroy wrote: you are the one who is affirming that there is a step by step path (each step being positive and achievable with 1 mutation) in the journey to evolve and eye or a flagellum.
No, we are affirming that we don't have reason to think there isn't one
given all the evidence we already have. This goes back to Darwin himself, who when he wrote the Origin of species, also supplied the conditions necessary for it's observational falsification:
"If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case."All it takes is one example of that, and then we would know that something else had to have contributed to the evolution of life, beyond just mutations, drift, selection, and population mechanics.
leroy wrote: You are the one who is making the positive claim, I cant prove the negative.
You're confused again. You don't seem to understand what it means to prove a negative, or at least you don't see how it is you who is demanding of us that we prove a negative in this particular case.
First, some background here: When Michael Behe started making the Irreducible Complexity argument, he was actually trying to meet Charles Darwin's criterion for falsification: Find an example of something your theory says should not exist.
You're not being asked to prove a negative, you're being asked to prove that there IS actual barriers to evolution out there that means (for example) that the eye, or the bacterial flagellum could not have evolved. You're being asked to prove that a particular thing DOES exist, you are not being asked to prove that it does NOT exist.
Rather it is YOU who is demanding of US that we prove a negative to you. All YOU have to do is find a SINGLE example of something that genuinely could not have evolved. Instead, you are demanding that WE prove to you that there are NO such examples. You want of us to prove that no barriers exist out there, an impossible task.
Suppose we did that for the eye and the flagellum, suppose we managed to evolve eyes and flagellums all the way from only a single original protein to the fully formed structure. You could then simply move on and ask "Oh yeah, but you haven't proved it for the nuclear pore complex, or the endoplasmatic reticulum, or the spliceosomal complex, or the mammalian inner ear, or the central nervous system etc. etc. It would never stop, it would be impossible to falsify the claim "there is no single barrier to evolution out there in any species of life that has ever existed".
We then have to "evolve" all these things for you to prove that there are no hidden "barriers" inside them, a completely ridiculous demand. Given the evidence already collected, the null hypothesis is that the diversity and functions of life on Earth evolved. A proper null hypothesis should be one that is easy to falsify, ideally by a single observation, which is why finding just a single example of an actual barrier to evolution could falsify the null hypothesis.
But if we make the null hypothesis to be "there are hidden barriers to evolution, somewhere, in some structure, or in some species, of some function we just don't know about yet", then it is almost impossible to falsify, because we'd have to literally evolve everything ever to show that null hypothesis false.
THAT is why it is you, who claims that there IS a barrier to evolution out there, that has the burden of proof: Because such a burden of proof
can be realistically met. It is like being asked to prove that a particular fossil exists in a particular rock layer. This can be done, it is practically realistic. You just go and look for it. And if you fail to find it, it doesn't mean it doesn't exist, just that you haven't found it.
If the reverse had been the case, if you had been asked to prove that such a fossil does
not exist, then you'd have to dig up all the billions and billions of tonnes of rocks of that particular layer all over the globe, an impossible and unrealistic task.
The neutral mutations required to evolve chloroquine resistance in Plasmodium Falciparum are supposed to be the very limits of what evolution can produce, and if it had required multiple double mutations, any single of which was lethal (for example), that WOULD have been an actual barrier.
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Re: Irreducible complexity and other creationist talking poi
