[00:00:04] Speaker A: ID the Future, a podcast about evolution and intelligent design.
[00:00:12] Speaker B: Welcome to ID the future. I'm your host, Andrew McDermott. Today, I'm pleased to welcome back Dr. Jonathan McClatchey, fellow and resident biologist at the Discovery Institute's Center for Science and Culture. Jonathan was previously an assistant professor at Sattler College in Boston, where he lectured biology for four years. He holds a Bachelor's degree in forensic Biology, a Master's degree in Evolutionary biology, a second Master's degree in medical and molecular bioscience, and a PhD in evolutionary biology. His research interests include the scientific evidence of design and nature, arguments for the existence of God, and New Testament scholarship. Jonathan is also founder and director of Talkaboutdoubts.com. Jonathan, welcome back.
[00:00:56] Speaker C: Great to be here. Thanks for having me on. It's been a long time.
[00:01:00] Speaker B: Yeah, well, we're enjoying the interaction here, and we're in person, folks. This isn't remote, which is a nice, refreshing
[email protected]. Our flagship site for news and commentary on evolution and intelligent design. You'll find a host of articles about the difficulties inherent in the popular RNA world scenario that's envisioned for primitive life. Now, Jonathan, you write there recently about another key problem for the RNA world hypothesis, the problem of minimal self replication fidelity. You say it poses a conundrum for materialists, so I thought we could delve into that a bit first. Let's start with the basics as we normally do. What is the RNA world, and why has it become so popular among origin of life theorists?
[00:01:46] Speaker C: So the RNA world is a scenario envisioned by origins of Life researchers. So try to circumvent one of the key problems in explaining the modern DNA protein system, right? So DNA codes for proteins, as we know, and proteins are needed in order to replicate and indeed to transcribe DNA into messenger RNA. And so this gives rise to a significant problem because if the DNA is needed to code for proteins and the proteins are needed to replicate DNA, well, which came first? And this is what we might call a causal circularity problem. It's more popularly known as a chicken and egg paradox. So the RNA world scenario comes along and it proposes a solution to this causal circularity problem, and that is to postulate that once upon a time, the chicken actually was the egg and that the RNA can serve as an information storage medium just like DNA can. And RNA, by virtue of its single strandedness, can actually fold to form complementary basebirds with itself and form three dimensional structures that could perform a limited subset of the enzymatic capabilities of proteins. And so the hypothesis is that RNA can actually serve both as information storage medium and also perform chemistry like enzymes. And so this has made the RNA world scenario attractive to origins of life researchers.
[00:03:20] Speaker B: Okay, so it builds as sort of a precursor to the DNA world. But as we'll see, RNA has limitations, right? I mean, you're not the first one to talk about the RNA world. I mean, Stephen Meyer in his book Signature in the Cell has talked about it. I believe it's chapter 14, a whole chapter on the RNA world. You also mentioned that Bill Dempsky and Jonathan Wells have written about it. Can you tell us a few problems with the RNA world? What are the limitations of RNA?
[00:03:48] Speaker C: Sure so there's a number I won't go into nitty gritty detail here. If you want a detailed treatment, then I recommend Stephen Meyer's book Signature in the Cell, in particular chapter 14 that deals with this in detail. You can also pick up a copy of Signature of Controversy, which is a collection of essays responding to critics of Signature in the Cell as well. I also recommend, of course, William Demsky and Jonathan Wells's book how to Be an Intellectually Fulfilled Atheist. Or not. And there's a whole section there, whole chapter there on the RNA world theory as well. Briefly though, so some of the key problems are number one, ribosomes can only perform a small subset of the chemistry that can be performed by protein based enzymes. Number two, RNA is significantly less stable than DNA. And there's a couple of reasons for this. In particular, the fact that RNA is single stranded, unlike DNA which is double stranded. And also RNA contains an extra two prime hydroxyl groups. That's a hydroxyl group at the two prime carbon and DNA. At the two prime carbon there is a hydrogen, hence it's called deoxyribonucleic acid because it lacks that oxygen that's found in RNA. Whereas in RNA you have instead of just the hydrogen, you have an oh which is called a hydroxyl group. And that hydroxyl group renders the RNA more prone to hydrolysis and that results in it being less stable than DNA. And in fact, RNA is notoriously difficult to work with in the lab by virtue of its instability. And this is why researchers actually reverse transcribe RNA into DNA. It's called cDNA in order to work with because it's much easier to work with DNA than with RNA because DNA is more stable. So it seems unlikely that RNA could survive in an early Earth environment. And of course, postulating the RNA world scenario doesn't explain the sequence specificity that is needed for life and so that has to be explained independently as well. So there's just a number of the problems and as I said, there's a lot more detail that one could discuss there. And I recommend the books that I mentioned previously for more detail on that.
[00:06:05] Speaker B: Sure, yeah. Okay, well, that gives us some of the basics on the problems. Now let's zoom into what this particular article is about that you've written. Why must the earliest genetic material have had a minimal replication fidelity?
[00:06:20] Speaker C: Sure so a minimal replication fidelity, that is, the accuracy with which the genetic material is copied, is needed to sustain life and for evolution to work. In fact, when the replication fidelity falls below a particular threshold. Modern organisms undergo what we call an Eric catastrophe from which they're not able to recover. And this has been shown in the cases of viruses, et cetera. So, for instance, viruses, especially RNA viruses, they actually sit close to that critical threshold. They have approximately one mutation per replication. And increasing the rate of mutations to result in an error catastrophe has actually been proposed in the literature as an antiviral strategy. And so the first life must have had a minimal replication fidelity in order for life and evolution to even work.
[00:07:15] Speaker B: Okay, and can you tell us the specific values that would need to be there in order to sustain life?
[00:07:21] Speaker C: Sure. So in the literature, the minimal replication fidelity needed to sustain life has been given as approximately equal to one minus one over l, where l is the length of the information molecule polymer. So the smallest ribosomes that have been documented are in the ballpark of around 50 ribonucleotides. And so for a string of ribonucleotides of this length, we might estimate that the minimal replication fidelity is going to be less than approximately 2% at each position, or a 98% replication fidelity. And if it falls below that, you're going to result in an error catastrophe. Now, what is the average error rate during RNA copying? Well, according to one study, this was estimated to be around 17%, which is a lot higher than 2%.
And I mean, you might be able to reduce that somewhat. So for example, with optimized nucleotide ratios, you might reduce that to something like 10%, and you might even be able to reduce that to 5% on GRC rich templates because U residues are known to be the biggest contributor to error rate because they result in a gu mismatch formation. And so you might be able to reduce that considerably. But even so, I mean, 5% is going to be a lot higher than 2% still. And even so, this, of course, assumes fine tuning and optimization of the sequence of the RNA.
[00:08:52] Speaker B: And when you say we can reduce it, you're clearly talking about intelligent design in the laboratory, right, not an early Earth scenario.
[00:09:00] Speaker C: Yeah, it seems quite unlikely that there's chemical researchers working in the early Earth environment to provide the sequence specificity needed to achieve that minimal replication fidelity.
[00:09:13] Speaker B: Okay. Now, at one point in your article, you say that natural selection is impotent to produce the high replication fidelity needed for life to thrive and for evolution itself to take place. Now, that's a powerful idea there to say that a natural selective process would be impotent, it wouldn't be able to do this. So is this the central challenge then, that it poses to theories of evolution?
[00:09:36] Speaker C: Yeah, totally. So in order to achieve this minimal replication fidelity, you cannot really appeal to natural selection without assuming the existence of the very thing you're trying to explain because the minimal replication fidelity is required for evolution to even work. That seems to require input of information specificity in order to attain that minimal replication fidelity. And you couldn't achieve it through a trial and error type of process because you need to have already arrived at it before the trial and error process can even kick in.
[00:10:14] Speaker B: Okay, that makes sense. Well, what about the folks that would say, hey, you're putting forward a god of the gaps argument. Just give us time, we'll find something that works. What positive reason then, could there be for inferring design is the best explanation in this case.
[00:10:29] Speaker C: Yeah, good question. So I'm a Bayesian. So I think about evidence in terms of a likelihood ratio, the probability of the evidence existing, given the hypothesis being true, against the probability of that same evidence existing given the hypothesis being false. So if you think about it in terms of a court scene where you have, say, the detective or the forensic expert comes forward and he demonstrates the presence of the accused fingerprints on the handle of a murder weapon, well, that is evidence for a guilt hypothesis over a non guilt hypothesis. It doesn't necessarily prove the guilt hypothesis, but it is evidence for that by virtue of the fact that it's a lot more surprising that the defendant's fingerprints would be on the murder weapon if he's innocent than it would if he's guilty. Or put another way, it's more probable that his fingerprints would be there if he's guilty than if he's innocent. And so that tends to confirm the guilt hypothesis. So that's how I think about evidence as abesian. Now, when it comes to biological systems and origins of life studies, et cetera, I would contend that the sorts of features that we observe in life are not particularly surprising if we suppose that a mind is involved, we habitually associate information content, information rich systems, and fine tuning and engineering with minds. And so if we suppose that a mind is involved, the source of features that we observe in biological systems, including this minimal replication fidelity, are not particularly surprising. Whereas on the falsity of a design hypothesis, in other words, on a naturalistic hypothesis, these observations become wildly surprising. And so in view of that top heavy likelihood ratio, I think that this strongly confirms design perspective over a nondesign perspective. And so this is why I'm an intelligent design proponent and of course, there are so many examples throughout the history of life and evolution and origins of life and so forth, where chance has to be appealed to that these examples are epistemically independent of one another, right? And so the Bayes factors, that is, the ratios of the probability of the evidence existing, given the hypothesis being true, versus the falsity of the hypothesis, when we work out that ratio, it comes out as what we call a Bayes factor. And these Bayes factors multiply together. To the extent that overall Bayes factor is top heavy, that's the extent to which we have evidence for our hypothesis. And in the case of biological systems, there's just so many examples where you have that top heavy likelihood ratio that, in my judgment, it puts the question of design essentially beyond question.
[00:13:11] Speaker B: I like the way you put that. Yeah, you can't really be looking for 100% proof, but you can look at where the likelihood of the evidence is leaning and as you say, which of your proposals is top heavy. And whichever one it is, that's the one that is likely going to be inferred as the best explanation. Great examples, by the way. Well, folks, as usual, this is a flyover of the topic. Jonathan, if listeners want to dig deeper into this issue, where can they go?
[00:13:41] Speaker C: Sure. So they can go to Stephen Meyer's book. As I mentioned earlier, signature in the cell DNA and the evidence for intelligent design. They might also want to check out William Demsk and Jonathan Wells book titled how to Be an Intellectually Fulfilled Atheist. Or not. I'd also recommend checking out the Discovery Science YouTube Channel and Evolutionnews.org. They can also go to my own personal website, Jonathanmcclatchy.com, and click on Latest Writing, which will take you to my articles. You can also find links to my videos at my YouTube channel there as well. And my articles contain information relating to intelligent design, science, faith issues, as well as New Testament scholarship and other interests of mine relating to worldview, et cetera. So check out these resources for more on this and much more.
[00:14:29] Speaker B: Okay, so lots of resources, lots of ways to dig deeper into some of these key issues as we look at the case for intelligent Design, but also the case against Darwinism, looking at the limitations of Darwinism when it comes to life's. Origins well, Jonathan, thanks so much for joining me and sharing your expertise. Thank you for Idthuture. I'm Andrew McDermott. Thanks for listening.
[00:14:55] Speaker A: Visit
[email protected] and intelligentdesign.org. This program is copyright Discovery Institute and recorded by its center for Science and Culture.
