Daniel Arant: Questions about Evolution and Design

I just finished watching this discussion with Michael Behe and found myself frustrated that certain points did not receive any follow up. I also found it frustrating that someone who is so close to the ID position in a broad sense would fail to appreciate the force of the arguments that Dr. Behe and others have made.

First I should say that I’m a layperson and I’m well aware that my knowledge is limited. That’s the reason I prefer to learn from watching debates rather than from just reading literature on one side of the debate. Usually it is extremely one-sided in favor of the ID theorist. The evolutionist usually fails to even understand the argument being made, let alone provide compelling counter arguments. This debate was far less one-sided the many of the others I have seen, and for that I think you deserve some commendation.

The first point which I would have liked to hear Dr. Behe press you on is this whole issue of genetic drift as a mechanism for gene fixation, and how that helps explain how certain evolutionary transitions took place in such a short amount of time. This claim actually makes me angry. Anyone who has spent any time talking to evolutionists will be familiar with how pedantic they are about pointing out that “evolution isn’t random” because although mutations are random “natural selection is non-random.” But if most mutations become fixed as a result of genetic drift, which is random, then evolution is actually far more random than evolutionists publicly represent it to be. And if evolution is such a random process, you then have to explain how it just serendipitously forms these systems of mutually-compatible parts that form functional wholes. In other words, to the extent that genetic drift helps explain the problem of fixation rates, it creates an equally big problem on another front. How would you address this issue?

You also glossed over a critical point about exaptation because you were too hung up on definitions. If exaptation means taking existing parts unmodified and repurposing them for use in some other context, then evolutionists need to show either that the individual parts of the flagellar motor each perform some function individually or as part of some other protein complex. On the other hand, if exaptation can also involve modifying existing parts to serve other purposes, then you have to explain how those parts were magically modified so that they all fit together to form the bacterial flagellum. In either case, these challenges don’t prove deductively that the flagellum is unevolvable, but it does mean that the best explanation we currently have is that intelligence was required.

This leads to another question that I wish evolutionists would answer. As ID proponents are fond of pointing out, Darwin said in the origin of species that if it could be shown that any feature of living things could not be explained by reference to a stepwise process, that this would effectively refute evolutionary theory. ID theorists have offered several such examples. I have seen no actual refutations of any of these examples where by “actual” I mean detailed, stepwise accounts based on empirical evidence. Instead, I find evolutionists promising that one day there will be an explanation if we just believe in the power of natural processes! But if scientists always assume that the future will yield some evolutionary explanation, then how on earth is evolution supposed to be falsified? How will they ever know that it is false if their faith is so unassailable that not even decades of failure to find explanations can shake it? Why can’t evolutionists simply admit that intelligent design is the best current explanation we have while continuing to look for other explanations?

Finally, there was another point that I wish Behe had pressed you on. At one point, again talking about rearranging existing parts for other uses, he brought up your example of a bone being repurposed for use in a flipper. He pointed out that there are a lot of intermediate steps that would have to occur to accomplish that repurposing. Your response was that the existence of intermediate steps makes the transition more plausible. But I think you completely missed his point (which is why he subsequently missed yours.) Just because we can imagine intermediate morphologies for a bone like this doesn’t mean that there is a viable molecular and morphological pathway from one to the other, where “viable” means that each step is biochemically possible and not mal-adaptive. Unless such a pathway exists, then our imaginary intermediate steps are pure fantasy, not science. So what evidence is there for such a pathway, particularly in the case of the various structures ID theorists cite of irreducible complexity?

I hope these questions send you on a fruitful investigative trajectory, and one that I, as a layperson, can benefit from.


Welcome to the conversation @Daniel_Arant. Can you tell us a little bit about yourself?

Absolutely! I’m a software developer from the US who has been interested in this topic and in biology more broadly for a very long time. For some reason I still don’t totally understand, I thought I could make the world a better place by getting a degree in Political Science and History, but if I had to do it all over again I would have gone into one of the hard sciences or mathematics. Instead, I content myself with making a hobby out of reading about biology and physics.

I’m also a Christian, so I come to this with a clear bias. I’m sure you picked up on that from my comments. :slightly_smiling_face:


It is difficult to think of a worse approach than trying to educate yourself through watching debates. Debates are in large part theatrics, and much depend on the debating practice and knowledge of the debater rather than what knowledge really exists out there produced by scientific investigation, which can be very difficult to summarize in a way immediately comprehensible to laypeople.
Some times a good response to a claim or argument takes time to first think about and then articulate, and might require ten times longer to really explain than it took to simply invoke the challenge first presented.


I am aware of those problems, which is why I don’t take what I hear in a debate as gospel. It’s just a starting point for further investigation.


That doesn’t follow. There are plenty of Christians who don’t have a bias toward creationism or ID. Perhaps it’s your particular brand of Christian, but you should at least be familiar with others.


Hi @Daniel_Arant, welcome to the discussion. As the parent of a history major, I would greet you with congratulations on your degree, and remind you that its never too late to add to your studies. Formally or otherwise.

You said:

I am not sure you are accurately relating the opinions of “evolutionists”, and certainly not evolutionary biologists. But you do make a good point, that it is wise and useful to ask, of most any perceived adaptation, if there was a random component in its origination. Devising experiments to ask these questions is a great way to challenge students and others interested in the subject.

The answer to this is pretty easy - there is nothing serendipitous (or improbable) about the evolution of complex systems. This perception that runs through the ID community is an illusion, and is not borne out by experiment and measurement.

Once this is understood, the question of random vs selected becomes even more interesting and challenging.

Again, welcome!


I’m quite familiar with others. I did not mean to imply that there are no self-professing Christians who are not biased in favor of creation or intelligent design. Dr. Swamidass was asking me to introduce myself, not the entire spectrum of Christian thought on this subject.

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Quite so. But your post implied that a bias in favor of ID or creationism was inherent to Christianity. That’s what “so” means; same as “therefore”. As long as we can agree that “I’m a Christian” doesn’t mean “therefore I have a bias toward ID/creationism”, no problem. But you should say that sort of thing if you know it isn’t true.


Thank you for taking the time to respond. I’m very excited to encounter a community of actual scientists who are willing to answer my questions. If I’m going to persist in my skepticism of evolutionary theory, I want to make sure I am skeptical of what such theorists actually believe and not just what I think they believe. I fully intend to make as few claims as possible and focus on asking questions, so long as there are other members of this group out there willing to answer them.

I have often said that if I could be a professional student, I would do it in a heartbeat. Unfortunately, higher education costs money or at least not earning money for a long period of time.

So would it be accurate to say, then, that evolutionists (and from here on, just assume that by “evolutionist” I’m talking about someone with relevant scientific credentials) now view evolution as a mostly-random process, where various forms of random genetic variation occasionally become fixed as a result of natural selection, but which are primarily fixed by genetic drift? The distinct impression I got from listening to Dr. Swamidass in this debate with Behe is that most mutations become fixed in a population by genetic drift, which would mean that evolution is little better than an appeal to serendipity.

That, I think, is where the crux of the debate lies. I have yet to hear of an example of a complex system that came about as the result of evolution. If such a thing is not improbable, then I would expect examples to be plentiful. Are they?

On the flip side, it certainly seems like the evolution of complex systems, particularly molecular ones, is improbable if not impossible. (a) because for any given length of DNA, there is an unfathomable number of possible sequences (b) out of those sequences, relatively few result in a viable protein and © out of the set of viable proteins, even fewer would actually be compatible with one another so as to form a functional complex. This is a line of argumentation which I have no yet seen a response to. What is missing from that analysis?

Thanks again for your warm welcome!


Technically, I think calling someone who doesn’t believe that God was intimately involved with the emergence and diversification of life on this planet is stretching the definition of Christian to the breaking point. But I’m not here to discuss religion. I was merely describing what perspective I come from as briefly as possible.


Welcome Daniel A! :slight_smile:
If we get many more “Dan’s” we might have to start assigning numbers. :laughing:

Maybe one of our Evo-Devo experts can give you a better answer in general, but the flipper example is fairly straight forward. A leg is a not-very-good flipper. It functions for swimming, but maybe not very well. Developmental changes, expressing more or less of certain genes during growth leads to intermediate changes. This does not require any new molecular machinery, only changes to regulation. I’m pretty sure these sorts of intermediate changes are well understood among the evolutionary development folks.


In the case of the bacterial flagellum, IIRC all but four of the proteins have homologues elsewhere in the cell, and functional variations (modifications) exist in nature. I won’t belabor this point as it is something we have previously discussed at great length. Many of the details are available in Pallen and Matzke’s 2005 paper. (pdf)


I have to agree, and I think a good example that shows these kinds of morphological changes in limbs shouldn’t be considered at all implausible or a barrier to evolution, consider the morphological changes we see that have resulted from selection on different breeds of dogs, particularly in the changes to the size and shape of the skull. The size and shape of the airways beginning from the nostrils, to the size of and distance between individual teeth, to the relative size and position of the eyes and their position in relation to the snout. All of these changes have been selectable among mutations in dogs in a mere geological blink of an eye.

I just don’t see why it should be considered any more difficult to render a limb wider, longer, and flatter?


I would agree the molecular machines are more difficulty to understand, at least for me (but there my understanding is even less). Behe’s requirement of a NEW molecular machine evolving in a lab seems to be asking an awful lot, since most of those are ancient (someone tell me if I am wrong?).


This one I know! A “detailed, stepwise accounts based on empirical evidence” would not validate evolution over design, because the designer could have used this stepwise process as well. A designer capable of complex design must also be capable of very simple design as well. Long story short, a designer that might do anything can never be falsified.

I usually use this example at the molecular evolution level, but I think it functions at the level Darwin observed too.

That’s why we don’t fall back on design as a default explanation, because that doesn’t offer any scientific explanation at all.


The question is what exactly counts as a molecular machine to Michael Behe. At what point does some protein being present, or binding to another protein, change from just being a variation of an existing structure, to graduating into a fully-fledged molecular machine? If we’re not told beforehand it’s a waste of time even trying to answer that, and we can be sure the rules are going to change as we go along if we don’t agree on definitions to begin with.

So if Michael Behe doesn’t think adding or subtracting a protein, or 2, or 3, counts as a new molecular machine, he’s going to be disappointed, because some things really do take more time to evolve than a few decades in a laboratory. I don’t presume Michael Behe has 125 million years to wait to see plate tectonics create a new mountain range. So I’d just say that if we can see mutations add a handful of components over a few decades, there’s nothing wrong with extrapolating futher such changes into the future to understand how a system could grow in complexity over time.

And in the same way we can infer that really large-scale changes has taken place in Earth’s geological history (just look at the shape of africa and south america, and the mid-atlantic ridge), we can also use comparative methods in biology to see that large-scale evolutionary changes have taken place in life’s history.

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How does that illustrate a stepwise pathway to a flagellum? A couple of dozen proteins that resemble the parts of a flagellum more or less vaguely (how much sequence similarity does there have to be in order for two proteins to be considered homologues? 50%? 75%?) are a very long way from a flagellum. I haven’t had time to read that paper yet, so if the answer is in there, just tell me to shut up and read. :wink:

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Read the paper first. Keep in mind that we don’t expect to be able to retrace every step.

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Better yet, read Matzke’s 2003 article on the flagellum which goes into much more depth:

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