"The Edge of Evolution" by Michael Behe

I found "The Edge of Evolution" to contain rigorous arguments to show why Darwinian evolution is not the means by which species were created. His main argument draws on our knowledge gained from the fight between humans and malaria. I found this book to be carefully and thoughtfully written, and particularly like the way his arguments rely heavily on calculations performed on the available data. I have been unable to find any counter argument, so I have begun this discussion.

Okay no problem, I will write a summary of the main points this week and get back to you.Thanks, Colin.

Consider the Malarial parasite as a real life case study for evolution. since an anti malarial drug "chloroquine" was first mass produced sometime during WW2, it is thought that malaria developed resistance to the drug about 4 times independently. Behe is happy to call this less than 10, to be safe. All of the known resistant malarial strains have common changes in 2 amino acids, located in a section of DNA which encodes for a protein pump.Other later drugs, put up much less of a fight, and became ineffective much quicker, sometimes just weeks. These drugs could be overcome by a mutation of just one of several amino acids.By taking the estimated number of chloroquine resistant strains (10) over the past half century, the approximate number of malarial parasites in each infected host (1 trillion), and the estimated number of infected hosts in the same time 10 million, the chances of malaria developing a resistance to chloroquine is approximately 1 in 10^20.Malaria has not yet managed to overcome the problem of the sickle gene in humans, despite having a much longer time to work with than with the drug chloroquine.Keeping in mind that only 2 essential amino acid changes were required, if 4 were needed for example, that number would be 1 in 10^40, which he says is less than the estimated total number of bacteria that have ever lived on Earth.Now, the total number of humans to have ever lived is easily less than
10^20 (even generously allowing for unknown ups and downs in population). How then, if the mind boggling numbers of malaria take so long to overcome a problem requiring just 2 changes in amino acids, can the piddling number of humans be expected to have achieved a transition from ape-like creatures with less population? (for example)Edited by Colin, : No reason given.Edited by Colin, : No reason given.

Hi, thanks for replying!You are correct about the 1 protein change conferring a partial resistance, and I have no reason to doubt you about the plasmodium achieving 4, but neither of these effect the argument because the amino acid changes do not feature in the calculations. It serves only to better understand the changes taking place, and perhaps rule out the possibility of the changes requiring a major overhaul of the organism.The probability calculations are taken directly from observable outcomes. Namely, population levels and frequency of resistant strains. The four hypothetical changes i proposed are specific to this example, and are in light of the probability calculated from observed occurrences. Other cases could of course achieve larger changes for reasons such as having more possible changes to choose from (as you suggest). I stress that the calculations are not reliant on the number of changes taking place. For example, say there are many more sets of possible changes malaria had to choose from. we would expect this to alter the observed instances of resistance developing.Getting back to the real life example. Malaria was free to find all and any possible changes to gain resistance, and at the end of the day we judge its ability to do so based on observed facts.Lastly, for Malaria this is a case of extreme selective pressure. A do or die situation. Not a general search for some advantage. Therefore it is not unreasonable to use this as a demonstration of how evolution acts to develop a species and overcome hurdles (I realize evolution does not "care" about hurdles - never the less this is what it does). If we deny ourselves permission to suggest evolution has any direction or trend from which to make predictions, It becomes a fit-all theory, with all the consistency of a piece of play dough.

As i mentioned in the last post (only posted literally 1 min ago - you probably missed it), Malaria was open to all possible solutions, yet took many trillions of organisms to find it. Even then, the solutions found always included the same two common changes, suggesting that any other possible solutions are even harder to find.

A friend of mine who does research into leukemia was talking about the robustness of cells sometime ago, but in favor of creation. I watched most of this video but i must have missed how it shows many solutions to evolutionary pathways are available. Perhaps you can summarize the calculations you are referring to. The calculations I referred to from Behe are from observed events, not simulations. There is not a lot of room to move. X number of malarial cells, Y number of solutions.

Hi Modulus, this is a good response, and i do have thoughts about this. I have been away from home since yesterday, so will reply to your post (and any others tonight - about 8 hours from now).Thanks, Colin.

Hello again, your are right when you say I am citing a specific and asking about a general. Let me discuss for a moment what I think Behe is getting at.Actually before this, let me discuss the issue of setting targets for evoluiton. I understand the fallacy of such comments like, the probability of humans turning out exactly like we see is x, which is very small, therefore evolution could not have occurred. I have heared this going around, but I do not believe this is the type of argument Behe is making. He has defined a unit of probablility which he calls a CCC, or chloroquine complexity cluster, which is the probability of an oraganism achieving a step with the difficulty of that faced by malaria, in regards to developing a resistance. This is a loaded statement and alone is enough to spark fierce debate. So let me read between the lines and lay it down the way I see it. As I have stated, this unit of probability is referring to observed events. In the thoretical world it is very hard to define. Imagine if we were to try to define this probability theoretically, before the outcome was observed. What is the chances that Darwinian evolution will find a solution in malaria for chloroquine? Well, we have no idea how many solutions there are, or how complex they are. We could call the answer a guess at best. But having ran the experiment we can see what actually does happen in the given time. Remember, malaria was free to try all and any mutations available for any solution, no matter how simple or grand. Including avoiding the problem all together by sourcing a different living. Is this setting a target for evolution? Yes. Absolutely. But is it wrong of me to say that evolution is said to be able to cause a species to survive due to the process of mutation and natural selection? No specifics were applied to this hindisghted test, other than to survive. And survive they did. Had they become extinct, this still would not be a problem for evoluiton. Since evoluton assumes extinction to be a relatively common event.The question is, can this specific example be used at all to make judgements on evolution in general? It depends on the assumptions we make, and what we believe to be reasonable. We are dealing with probability after all. If you assume that this is a special case, and normally the process of evoluiton would have found many solutions much sooner, then the discussion can not really go much further. If however, the step from suseptible to resistant, is typical in likelyhood to other problems, then evolution has a real problem.Let me discuss the problems bit, form above. Again, evoluiton has no foresight, no ambition, no plans. But we do believe it tends to develop a species into other species, correct? For example, given a primitave Earth with little variation in species, can we expect evolution to create diverse eco systems? Or is what happened here on Earth just a lucky lottety ticket? Given what we see around us, and assuming evolution to be true, can we conclude that evolution acts not only to develop a species so that at least a small number of brances will continue to reproduce, but that the trend will be upwards evolution, to more complex organisms. If we assume that life on Earth started with simple celled organisms, it cannot exactly go backwards. Like I said, the option of concluding that Earth is just the lucky planet is always available, which, i'll change my mind, will probaly lead to completely different topic of debate rather than end it. So by problem, I mean, from a particular state, a species has many steps set out before it. Some lead to death or deformity, some are neutral, some impede the creature, others benefit the creature. Where I believe we may disagree, is on the issue of how many options are open that will benefit the species? And how likely are they? I dont think the available options are plentiful. If a structure for something or other is partially complete (I know, targets!) there is a limmited number of useful, beneficial ways in which to improve this structure for the species sake. But this is talking about hypothetical machines. A shark didnt need to develop long range sensors, it could have developed a signal generator that lured fish right into its mouth! For example. But how can we possibly imagine all possible scenarios and then decide how likely they are? Maybe some day, but not now.That is where Behes unit of probability comes in. If, developing an advantage in an environment is on par with the difficulty of malaria developing an advantage in its environment, then we can estimate the likelyhood of it happening. If more solutions are available from that point, the species is more likely to prosper. If the solutions are also more simple, the species is again more likely to prosper. (I know there is much more on this to be said)The question is, in all the possibilities open before an organism, how many are there that even create a working thing? And how many of these are beneficial to the creature? And how do these options remaining, compare to the task of developing ANY soluiton to a poisonous drug to trillions upon trillions of malaria?Edited by Colin, : No reason given.

Hi, "targets" is a big topic in its self, and i know iv'e left myself open. I have responded a little about this to modulus's comment. But i am not avoiding the issue. I will go into more detail a bit later.

Yes, this place is definitely growing on me! About the big "if." It is a big if, but not totally necessary. I don't think for a moment he is suggesting that all advantages are as complex, he is just making an arbitrary benchmark for comparison. But i think he is assuming it is not all that special either, in terms of developing new body plans in general, in one of MANY directions.There surely must be a limited number of the potential advantageous mutations in mammals for example, that you refer to. In trying to compare this situation with malaria, you are correct in saying that firstly malaria had a very specific problem and the solution was highly selective. This is true, but necessary in order to be able to make any reasonably defined calculations on the observations. It would be very hard to judge or even keep track of general advantageous changes. But also keep in mind that the type of solution or mutations were not limited for the example. So, getting back to comparing this example to the potential mammal examples you talk about. Under no specific selective pressure, a whole new diverse range of options are open, making the event more likely. However, the number of trials are greatly reduced, even considering our macro bodies, to the comparative number of malaria, reducing the probability. Also, I believe Behe would have probably had in mind the fact that if an advantage requires a string of changes, even accounting for the range of multiple possible paths along the way, the event of finding any advantage becomes more unlikely. Again, I think we have different perceptions or expectations about how many legitimate paths of advantage are actually open. Dawkin's if i remember rightly, refers to this as "animal space" or something similar. It could be imagined as three dimensions, but in fact would have many dimensions. Legitimate paths would consist of small beneficial steps, connected by reasonable possibility of achieving those steps, leading to more complex structures that also give advantage. From an engineering perspective, i imagine these paths would be very tight. In the last comments, i realize i am again attributing goals of some sort to the process of evolution, but only in the light of observing our world, and assuming that this must be the trend.

I must admit, I had misunderstood your first argument. The section where Behe is talking about this, he mentions things such as the time taken for the first resistant strain to show, the fact that when the drug is removed the resistant strains decrease, and uses the words "spontaneous resistance" to describe new cases of resistance. Reading between the lines, I suspect that the sources he cites for this information were able to tell the difference between inherited resistance and spontaneous resistance, and would have the common sense to not include malaria carriers of resistant strains in a region as "trials" to find an already present resistance. Of course this is an assumption, i wonder if Behe himself would be willing to comment on this by email. It's worth a try. It is clear that the history of chloroquine use is not as simple as assuming continued widespread use in regions despite a known resistance being present. Will have to do some research and come back to this. (in the interest of thoroughness)--- Major New Line of Argument --- No sidestep intendedI had forgotten, but another post reminded me that Behe makes a point about another resistance that has yet to be overcome at all, based on our current knowledge. And that is the sickle gene. Apparently thousands of years old, the trait gives a person resistance to malaria, and to date, malaria has found no solution. This is highlighted by Behe as an example of something evolution cannot seem do (at least yet). Again considering the vast numbers of malaria available to crunch the numbers, such a case suggests that if a step of similar complexity stood between our ancestors and a particular beneficial mutation, it would not happen. Even giving that at any one time, not one, but many such opportunities for developing an advantage may exist. The number of potential (and theoretical) paths to advantage, could not reasonably offset the population size of malaria.Again, the obsession with malaria here, is that it is a real example of evolution causing an organism to adapt to its environment, and the efficiency at which it does so. You may suggest that with such deep time on our hands efficiency is not really an issue. But if organisms are said to crack the code to successful body plans with "brute force," then even with deep time, efficiency remains an issue.

Hi Modulus, just a quick question, how do you put my quotes in the blue highlighted boxes? It would be easier for me to respond to people using this. Is this a feature of the site or do you just cut and paste?Since the number of potential evolutionary paths is unknown, let me work backwards. Behe puts the probability of chloroquine resistance at 1 in 10^20. Although he he himself claims to have been very conservative, lets say he was way too pessimistic by a thousand fold, and put it at 1 in 10^17. You suggested 36 x billion for human ancestry, lets make it a trillion. The easiest way to proceed from here is to set up an "even odds" situation, (a 1 in 10 chance gets 10 trials). Not the most mathematical approach, but it is just an illustration. I will leave the unknown value of potential pathways with the "loose change" from the even odds.Referring back to the "big if" you mention. This comparison draws again on the benchmark of chloroquine resistance. A step of similar difficulty for other species could be anything, and without the specific nature of this step. It could be an adaptation that improves the eye, or memory, or gives resistance to cancerous cells forming, anything. In using the Malaria example, Behe seems to have assumed that a step of this complexity would not be remarkable in nature, assuming evolution to be true.This part is important. In achieving this step, although malaria had a very specific problem, it was not restricted to any specific solution. Indeed how could we, it is a real example. We can assume that any genetic stage setting, drifting, duplicating, inserting, deletions of any type, were open for use.Getting back to the numbers, 1 in 10^17 chances with 10^12 trials, leaves 10^5 in change. In other words, if all 1 trillion creatures on the line to humans each had 100000 feasible steps to gaining an advantage of similar complexity to the step of developing chloroquine resistance, there would be even odds of such an event happening once in all of history on our branch. Note: This example does not limit the changes to those which lead to "human." Feasible steps refers to any advantage, including growing gills, wings, six legs, anything. Consider also, we are not just looking for one occurrence, we are looking for many, many steps of change.BUT, nothing is special about our branch on the evolutionary tree! It could have just dropped off and who would care? If ours perished, another would prosper. No, this example does not discriminate on where a branch should lead, and does not assume any necessity for the human line to survive. It deals with the difficulty of a branch propagating anywhere, since each of the proposed 100000 options represent a potential "off shoot" from the branch. The existence of other species shows only that this is not a unique event, and that many "off shoots" also continue to propagate.

Okay, thanks.About the feasible steps. Imagine "animal space" with some details of my own added in, and without referring directly to genes. Imagine the trillion creatures directly preceding living humans. Extended back as far as necessary until a trillion is reached. I imagine this will go back several million years, and may include some of our cousins. When we reach one trillion, we may have stopped on a small community of some primate looking things. Lets say that every one of these creatures, right up to all modern day humans, each have 10000 opportunities to pass on some mutation comparable in complexity to that needed to cause chloroquine resistance in malaria. In referring back to your query, a feasible step here means any number of possible mutation clusters that will lead to some advantage in some way. I suggest 10000, which I arrived at arbitrarily in order to produce an "even odds" example at the end. I have no idea what this number actually would be - we are talking about hypothetical biological machinery. So, if each of these trillion creatures, each had 10000 such beneficial evolutionary steps open to them, there would be even odds of just one of these steps being taken in the whole trillion creatures. (Please note: I am again using the step to chloroquine resistance as an ball park estimate of the difficulty of taking a modestly complex, beneficial evolutionary step.)PS. Its been a long day, if this still doesn't make any sense i will come back to it.

Hi Dr Adequate,Ive just been rereading your posts. Have you read the first part of message 23, and does this apply to the argument you made about Behe's probability argument? If not, could you remind me.Thanks.

Indeed, in an exercise of playing with variables this is an equally legitimate calculation. My interest in considering different types of changes comes from a desire to consider the nuts and bolts of how mutations can actually produce new features, and what sort of gaps are in place between even the small steps. If we consider the evolution of the eye, it would be good to know what specifics are involved in making a group of skin cells distinguishably more photo sensitive than the others. And then, what further genetic changes are required to produce some sort of cavity, to gain some directional perspective from those photosensitive cells, and so on. Whether Behe's calculation is common or not, it would of course not be unique. We always expect for sure that some mutations would be less likely and others more likely. The purpose of looking for any such estimate is similar to say, the necessity to find the probability of flipping a head on a coin toss, in order to find the probability of flipping several in a row. The difference of course is that we don't have a standard "head" in this case, but many different possibilities with different probabilities. So any ball park estimate is by no means a rule, and if Behe's estimate is indeed not typical in terms of the steps available, then I would expect the argument to break down. His assertion is though, is that life is full of features requiring many such steps to be taken. Of course, we would still need to account for how many similar steps are available at the same time, just as holding several lottery tickets is different to holding just one. we don't really care which ticket wins. Indeed, we would expect steps of lower complexity to be achieved more often. I would agree with half of this. "Complex," here i would imagine refers strongly to the probability of a specific adaptation occurring from the creatures current position. The more solutions there are, the less complex the adaptation. The less amount of changes necessary, the less complex the adaptation. So a specific 10^8 would not be more complex than a specific 10^20, but a specific 10^8 could be more complex than a more general 10^20. In this particular I do not think his calculations are off, because the resistance was not restricted to a specific mutation, but to any. what I would not agree with is the first sentence. I think the ease or difficulty of acquiring a characteristic could by definition be called the complexity. Whether it is a measure of evolution in general is another question. For that we need to consider how typical that level of complexity is, and the number of alternate paths.