[00:00:04] Speaker A: ID the Future, a podcast about evolution and intelligent design.
[00:00:12] Speaker B: Science is a very human enterprise, and very human problems can color scientific research as well as the narratives cast around evidence and findings.
So how do we separate fact from hype? Welcome to I Do the Future. I'm your host, Andrew McDermott.
Today we're sharing the first half of a conversation with Dr. Casey Luskin that originally aired on the Come Let Us Reason Together podcast hosted by Lenny Esposito.
Casey discusses the growing controversy surrounding Sahelanthropus tchadensis, a fossil often described as one of the earliest human ancestors.
But what began as a celebrated evolutionary discovery has now sparked open disagreement among evolutionary scientists themselves.
In this segment, Casey reviews the history of paleoanthropology, what the field is trying to prove about human origins, and how language bias, politics, prestige, and funding pressure all play a part in how discoveries are framed and evidences weighed.
Now here's Casey Luskin and his host, Lenny Esposito.
[00:01:20] Speaker C: Good day, everyone. Welcome again to Come Let Us Reason Together. I'm Lenny Esposito, and as I said, we are going to be exploring the interesting and sometimes controversial aspects of doing anthropology, paleoanthropology as it is, where we're trying to understand where we came from and what the fossil evidence actually shows. Now, in order to help me with this, I've asked Dr. Casey Luskin to join in. Casey is a senior fellow for the Center Science and Culture at the Discovery Institute, and he's written a couple of really interesting articles on this new discovery and the blowback that's happened within even different factions of the evolutionary community trying to get a handle on this. So, first of all, Casey, welcome. I'm glad to have you here. Glad to see you, and thanks for, you know, having this article come out. I think it's really an interesting topic that we want to cover.
[00:02:22] Speaker A: Oh, thanks for having me, Lenny. It's great to be back with you.
[00:02:26] Speaker C: Okay, so let me just ask you a couple of things. First of all, I've used this kind of scientifically technical term, right? We. We've. They found this fossil. Now, this was found about six or seven years ago, if I'm correct.
[00:02:42] Speaker A: Well, the first fossils from the species Satelanthropus tudensis, which, by the way, is just about impossible to pronounce. So, I mean, these taxonomic nomenclature is infamous for being very difficult to pronounce. So if anybo mispronounces, it will have nothing but grace. But the fossil was first found, I believe, in the early 2000s in the country of Chad.
At that time, they found at the very least a skull. But over the years there were rumors that maybe they had also found a femur.
We can get into that, or at
[00:03:12] Speaker C: least a partial part of the femur.
[00:03:14] Speaker A: A partial femur. And they wanted this species to be an upright walking. So a bipedal early hominid that might have represented one of the first species that kind of was one of the human ancestors that had branched off from the supposed most recent common ancestor we shared from chimps. So basically the idea is that this fossil, according to some evolutionists, would have been sort of at the dawn of the human lineage after our supposed split from chimps, one of the first upright walking species that was on that line that ultimately led to humans. And, and the supposed ability of this fossil to walk upright was one of the main lines of evidence that they would cite to say this is a human ancestor.
[00:03:55] Speaker C: Okay, so yeah, when we talk about the great apes, because it's commonly referred to as our quote, closest ancestor in the evolutionary tree, the great apes are either knuckle walkers, like the gorillas, right. They don't necessarily just stand up and are bipedal chimpanzees while from time to time move that way. But it's awkward for them and they don't do it on a recurrent basis really. They're, they're much more.
They plant their forearms and then swing their hips in their rear section forward and kind of move that way. That's their locomotion. So this is. So bipedalism is something that would be kind of unique in the line of hominids.
[00:04:43] Speaker A: Right.
[00:04:43] Speaker C: And it's supposedly one of the primary centering point or primary separations between hominins and other hominids. Is that, is that a fair way to say it?
[00:04:55] Speaker A: It's pretty fair, yeah. I mean all the great apes are quadrupeds, okay. They all walk on all fours. Gorillas, chimps, bonobos, they all engage in a lot of knuckle walking.
Orangutans, they also walk on all fours, but they might not use their knuckles, they may use their palms. And they also, orangutans spend a lot more time in trees. And then some of the other apes, like gibbons, they also spend a lot of time in trees. But all of them do engage in some kind of knuckle walking, quadrupedal locomotion when they're on the ground. And obviously humans don't. At least you don't after the age of like two, and we don't even knuckle walk, we, we crawl on all fours. So it's not. The human mode of locomotion is very different from that of the great apes and the other apes.
[00:05:41] Speaker C: So there's, and then when we, when we talk about this, what they're looking for, what they're hoping to find, is to find a new discovery, or at least to a catalog an, a fossil that would show there is some distinct intermediate form between, say, an ancient ape and modern humans or modern hominins even. Even if that's, you know, Australopithecus or something of that nature. Right. Australopithecus is a biped, if I, if I remember right.
[00:06:19] Speaker A: Yeah, so, so even that can be somewhat controversial. But yeah, the idea would be that this would have been a very early human ancestor. The australopithecines would have been descended from this species, potentially Sahelanthropus tchadensis. And the Australopithecines, that's a whole other conversation. They also spent a lot of time in trees.
They probably were capable of some upright walking, but there's good evidence that they also engaged in knuckle walking as well. So it's a mixed bag there. It's actually not that different in some ways from the species we're going to talk about today. It's not a human mode of locomotion. At the very least you can say that much.
[00:06:59] Speaker C: Yeah, so we're looking for that central ancestor, that, and in the popular parlance you use the term missing link. Now I know that that's a lot of folks consider that a loaded term, missing link, because it's, it's non scientific, it's really used more generally within the, brought the untrained community, so to speak. So a lot of people will, will push you away or, or dismiss you if you use the term missing link. Unless of course, you're someone like say the New York Times.
Whereas the New York Times just recently published a story about another fossil and they used the term missing link even in the headline because they wanted to make that.
It's a, it's a quick phrase that people kind of grab onto and understand.
And so while it may not be used in the scientific community, it is used in popular media quite a bit. Is that, is that a fair assessment?
[00:08:00] Speaker A: That's very fair, Lenny. I mean, if, if we were to use the term missing link, then our friends from the evolutionist community would immediately say, oh, you backwards creationist. Don't you know that scientists don't use the term missing link? And this is not really A real term used in scientific literature. And they're somewhat correct to say that. I mean, you can find the term missing link occasionally in the scientific literature, but it's not the case that when scientists are talking about these fossils in a technical paper, they're going to say, oh, this fossil is a missing link. However, in the popular conversation and certainly in the mainstream media, as you just correctly pointed out, Lenny, I mean, New York Times just had a story a couple weeks ago that said that there was a hominid fossil that was a quote unquote, missing link. So it's a term that's out there in the real world. I don't use that term very much, but if other people are using it, certainly it's fair game to talk about it. The term that is probably more commonly used in the scientific literature would be for them to say this is an intermediate, or this might be some kind of a transitional stage between this and that.
But yeah, and whatever. They all kind of mean similar, similar concepts.
So.
[00:09:08] Speaker C: Yeah, so the term intermediate form or would be basically it's synonym. And, and, and I think folks are backing away from the missing link phraseology because it has a lot of baggage behind it.
[00:09:21] Speaker A: Right?
[00:09:22] Speaker C: I mean, when we talk about this and we look at the history of supposed finds that point to the missing link, well, what's interesting and what's kind of germane to our discussion is in the 19th and 20th centuries, just how much outright fraud was going on within the scientific community in order trying to find a missing link. Right. Piltdown man, Nebraska man.
There are these are some very famous cases where, where they were actual deceptions that were being proffered as, as, you know, amazing finds in order to bridge this missing link.
And it really falls out of the Darwinian model of evolutionary development. Right. The idea that the slow, successive, gradual changes what I would call the Richard Dawkins blind watchmaker hypothesis, that slow success of gradual changes based upon, because of random genetic mutations have produced the diversity of body plans and species we see today. That's, that's how we see it for. And because of that, that means there has to be some kind of intermediate state. There has to be some link between a small proto, you know, hominin and what you and I are today as, as fully fledged human beings developed with all of our characteristics and all of our biological traits. There has to be something in between there.
Just simply because you go from, from, you know, parent to child, right. You have progeny, and that progeny slowly and successively changes. This is the model And I'm going to leave out some of the changes of Evo, Devo and all of that stuff too. But there's still, there's still a progression that has to take place. And so using the term missing link, I think got tainted, perhaps because of all the bad press. So we talk about intermediate forms, but I don't know that there's a difference. I don't know how you can distinguish what an intermediate form is and what a missing link is. If there's, you know, I don't know how you make a distinction between it's an intermediate form, but it's not a missing link. I can't understand where that difference may fall.
[00:11:51] Speaker A: Yeah, I mean, I think that the term missing link is commonly referred, being used to refer to a specific aspect of evolutionary history that deals with human origins. And the missing link, quote unquote, is supposed to refer to some human ancestry that we didn't know about that finally shows that we are descended from ape like ancestors. Now, we're not allowed to use the term missing link, but the New York Times is, okay, so there's definitely this disparate and unfair treatment. And you know, who's allowed to say what in this society, however that is when people use the term missing link, that's what they're referring to. That it says, supposed to be a fossil, that finally it's been found demonstrating our connection to ape like hominid ancestors.
[00:12:35] Speaker C: It's interesting, Casey, because, you know, even when I talk about things like evolution, evolution can take on the meaning that the objector wants it to take on, given whatever circumstance you're talking about. Right. So, so I just gave a description of again, that blind watchmaker hypothesis that gradual change through, through random mutations that cause new body types to appear. Okay. And, and we would say that's, that's evolution. But they would also say, well, evolution simply means change through time. Or when I talk about the origin of life, abiogenesis. Right.
You know, and I say, well, evolution fails there. And they say, well, you can't use evolution. Evolution doesn't apply here because evolution has to have living organisms in order for that to evolve. Yet when I pull out, you know, the National Academy of Sciences paper and they have an entire chapter on chemical, chemical evolution, and so they use evolution in. Are you saying the National Academy of Sciences isn't doing science? What are we saying?
[00:13:44] Speaker A: Absolutely.
[00:13:45] Speaker C: So again, there's a lot of, even here, even before we get started with, with digging into the actual find, even in terms of language, there is a lot of ground that people are trying to stake in order to save face it, it should at least caution us that this entire enterprise is rife with dangers, with political motivations, with motivations other than simply just trying to understand what it is we've found and having no preconceptions or no biases being flavoring our examination of the evidence.
[00:14:30] Speaker A: You're making great points, Lenny. And I think anytime that we see these double standards that certain people, certain favored groups are allowed to use certain terms, but certain disfavored groups are not allowed to use certain terms. When you see those kinds of rhetorical double standards, the red flag that should go up in your mind is that people are trying to silence certain groups or certain viewpoints through rhetoric, not through evidence. And that's exactly what's going on here. The whole chemical evolution thing is a classic example. I remember when Stephen Meyer went on the Joe Rogan show a few years ago and he was talking about chemical evolution and people said, well that's not. Some of his critics say well that's not evolution. Well, the term chemical evolution is all throughout the literature, textbooks, mainstream scientific papers. It's commonly referred to as a class of evolution. Now it's different from Darwinian evolution where after you get self replication then you can start to have natural selection taking over. And that's a different type of evolution. But chemical evolution is absolutely a form of evolution that's supposed to get you from basically non living chemicals to, to the first self replicator. And once you have that, then according to the theory, you know, natural selection, Darwinian evolution can take you the rest of the way. But they're both forms of evolution. So anyway, we get these double standards all the time being used against us. But look, I don't care, I don't need to use the term missing link. We can talk about, you know, these intermediates and whether there really is good evidence that humans are evolved from ape like ancestors.
[00:15:57] Speaker C: Sure, sure. And I'm not. Again, this may seem like a, you know, a red herring or something like that, but all we're trying to say is the, the field of evolutionary biology has political biases kind of built into it, even from the point of view of language. So to, to assume that the majority of scientists hold to evolutionary theory because they simply follow the evidence wherever it led to is a little naive. Especially when those who are presenting the evidence have biases of their own and have motivations of their own that may or may not help in uncovering the truth. And this Sahelanthropus is, is a Perfect example of this. So you wrote a couple of articles on this. Casey, why don't we first talk about what the find was and what the initial announcement was for this find and why it caused such a stir.
[00:17:04] Speaker A: Okay, so, yeah, so when this fossil was first reported in the early 2000s, they basically reported a skull from the species Sahelanthropus tradensis. But there were rumors for, you know, almost two decades that there was also a part of a femur that had been discovered along with the skull. And if that's the case, that would be a very important bone for understanding whether this fossil really was an upright walking bipedal human ancestor. I mean, the skull can tell you a little bit, but really, you know, bones like the pelvis, the femur, those are the crucial bones. You know, you can learn about the knee joint and the hips that will tell you whether or not this was an upright walking organism.
But what was weird, and we can get into this, is that although there had been rumors that there was a femur associated with Sahelanthropus, nobody had ever published about it. And then finally, I think in the year 2020, there was an article in the Journal of Human Evolution that came out that did finally discuss the femur of Sahelanthropus chinensis. And that paper said, okay, this femur is actually not the femur of an upright walking bipedal organism. It's from a quadruped, a chimp like body plan with a chimp like quadruped knuckle walking mode of locomotion.
And that was in 2020. But that then led to a number of other articles that went back and forth in the Journal of Human Evolution and other journals about this femur. Some researchers were saying it was bipedal, others were saying it was not. And this paper that just came out in Science Advances is kind of like the latest foray or latest volley in this back and forth.
And this article is saying that it was in fact a bipedal. And they're saying that on the basis of a couple of features, they say that there is something called a femoral tubercle, which is sort of like a little bump that is on the femur that is only found, they claim, at least in bipedal hominins. And that basically there was also part of the hip that indicated that there was probably in the knee function that was probably only found in bipedal organisms. So that is what this paper in Science Advances is arguing. And of course, a lot of people came back and had responses to that, but that's the claim being made in this paper.
[00:19:23] Speaker C: Okay.
And I want to be careful because there's an evolution to the story as much as anything else.
For example, a paleoanthropologist at New York University who authored the study, Scott Williams, he said in a news release, cellular Anthropus chadensis was essentially a bipedal ape that possessed a chimpanzee sized brain and likely spent a significant portion of its time in trees forging and seeking safety. That's, that's the way the, the quote said in the news release. And he goes on to say, despite its superficial appearance, appearance seller Helenthropus was adapted to using bipedal posture and movement on the ground.
So, but it's not that they found a full skeleton. This is, you know, normally you hear this kind of thing, you think, oh well, let's rebuild the whole thing. They don't know how much of this body plan resembled humans or resembled apes or resembled anything in between.
What was it that they actually found and what was it that they initially released to the broader scientific community so that others could either verify or challenge the initial findings?
[00:20:39] Speaker A: Yeah, so initially they just found a skull, or at least that's what they claimed. But there are rumors that there was also a femur, but that femur, the proponents of the view that this fossil was bipedal, they never published on the femur. The first group to actually publish on the femur, as far as I'm aware, was actually critics of the view that this fossil was bipedal. That's an interesting point we'll come back to later that maybe they sort of forced them to talk about the femur by having the critics of the bipedal view published first. And by the way, even the proponents of the view that Sahelanthropus chinensis is bipedal, they're not saying that this was a full time bipedal organism, it was not an obligate biped. They're saying that it was a quote, early form of habitual bipedalism, which means that sometimes it walked on two legs, but it was also probably engaged still in some form of quadrupedalism. Also as you noted, spent a lot of time in trees, so there was a lot of tree climbing going on. So this was not something that even the proponents of the bipedal view believe that this ape like species was walking around on two legs just like a human being. But if it was doing that, you know, at that time period, it's thought that would have been an intermediate, not a missing link. But an intermediate stage in the evolution of bipedalism. So that's the hope. But yeah, so what they released, they've now released to the public both the analysis of the skull and of this femur. So I think it's fair to say that as far as what bones we think are associated with this fossil, it's all been published at this point, but five or six years ago, say in early 2020 or 2019, only the skull had been published. And the question remains, sort of, why did it take them so long to publish on this femur? And that's the interesting part of the story that gets into the politics, which I'm sure we'll talk about.
[00:22:37] Speaker C: Well, this is kind of part of my point because again, when we talk about science and we talk about how science proceeds, how it grows, how it discovers things, we talk about publishing in journals, and those journals are peer reviewed journals. But peer review can only work if all of the data is supplied so that peers who may be skeptical or at least want to honestly review the data can do so in an objective way. They need to have all the data in order to review it with these published papers. If you're just talking about the skull, I don't know, first of all, how you can claim bipedalism from just a skull, that's. So if you don't release the femur, you know, it seems like you're just kind of grasping out of nowhere. And I'm not quite sure how they made the justification to say that this was a bipedal organ.
[00:23:35] Speaker A: Well, I can, I can speak to that really quick. Okay, yeah, you're right. There's not a lot to go on with the skull.
But one of the things that they do have to go on is the hole at the base of the skull where the spinal cord exits the skull is called the foramen magnum, okay? It's a hole, everybody. Every thing with a brain and a skull has a foramen magnum, okay?
And the angle at which the spinal cord exits the skull can kind of tell you are you walking on all fours where you're kind of hunched over like this, or are you upright where the skull just, you know, the spinal cord exits straight down below.
And so that was one of the arguments that was made. But even that was controversial. I mean, even when the skull was first published, there were researchers who said, no, this was not bipedal. So the initial finders of the fossil, I believe a scientist from France named Brunet.
Brunet was saying, yes, this is a bipedal organism based upon the skull. But even at that time, there were critics who said, no, this organism is more like a chimp or a gorilla just based upon the skull. So there's been debates back and forth over whether this was a bipedal organism from the very beginning. And even now that they've analyzed the femur, there are major critics of the view that the femur indicates that this was an upright bipedal organism.
One paleoanthropologist named Roberto Macchiarelli said that the body proportions in Sahelanthropus are 100% ape like, certainly not ape, hominin intermediate, unquote. So, you know, talking about the size of the femur and its length and other properties, he's basically saying this is a totally ape like, quadrupedal type organism.
Another scientist named Zanoli, who was a co author with Machiavelli on a paper critiquing the bipedal view, said that most of, not all of the results point towards similarities with the African great apes. And so, you know, these scientists are very skeptical of this claim. Other people criticized the claim that that tubercule on the femur, which is supposed to be indicative of bipedal locomotion, that that's actually found in other primates that don't walk upright. So it's really not that convincing. And I guess the femur is in such bad condition to begin with that it's not entirely clear how important or how prominent this tubercule was. Okay, Was it really this bump that they really think that it should have been in order to indicate upright walking? It may have been damaged and it may not really even be there to the extent that's being claimed. So there's a lot of questions about whether the evidence shows that this species is upright, even based upon the femur.
[00:26:18] Speaker C: Well, let's, let's talk a little bit about exactly how the femur got into, involved in the discussion, because you brought up Machiavelli, and if I remember in your article, you had said it was actually a student who was working with the original discoverers who had seen the femur or the portion of the femur. I'm not quite sure how much of the femur was actually uncovered, but and had questions and she was studying, getting her PhD, right.
And said, came up to Macarelli, who's an expert in the field, he is a, he is a significant name in paleoanthropology, and then brought this to his attention and somehow that upset the apple cart a little bit. And now they had to deal with it. So can you tell that story?
[00:27:15] Speaker A: Yeah. So let me say first of all that the newspaper in the uk, the Guardian, has done some really fascinating reporting on this fossil. Even with this latest paper in Science Advances, Macarelli was quoted saying that paleoanthropology is deeply affected by competition and politics.
And I think what that came from is there was an article in the Guardian that came out the previous year in 2025, titled the Curse of Tomai. That's another name for this fossil, the Curse of Tomai. An ancient skull, a disputed femur, and a bitter feud over humanity's origins.
And this article told the story of the supposed origin story of this femur. Okay? And the story goes, as you said, Lenny kind of goes like this.
Initially, everybody thought there was only a skull associated with this fossil. But then there was a graduate student who was on the team from Michael Brunette in France, who was studying a bunch of hominid bones. She was a master's degree student. I guess her advisor was out of town, and she asked Roberto Macchiarelli, who was another researcher there, to help her with some identification of the bones. And, you know, I remember being a graduate student, and if your advisor's out of town and you need help, where do you go? You go to other faculty around, you ask them, you know, can you help me figure out how to do this? You know, you're learning, you're trying to get it right and make sure you don't make mistakes. And it's great to get assistance and learn from the researchers and the experts that are around you. That's part of what being a graduate student is. You struggle with it, you learn, blah, blah, blah. So she asked this researcher, Roberto Macchiarelli, to help her identify this bone, which apparently was found with the other Tomai skull, with these other Sahelanthropus fossils. And he looked at this bone and he said, okay, this looks like a femur.
And this immediately, in his mind, made him wonder, well, why hasn't this been reported? Okay, because the discovery of a femur in the field of paleoanthropology is a very, very big deal. Okay? Most.
Most bones, most specimens of fossils that you find in the hominid fossil record, they're going to be scraps of jawbones or teeth or little vertebrae here and there. Rarely do you get complete. Very, very rarely do you get complete skeletons, even more, you know, and also very rarely do you get crucial bones like a femur or a pelvis or something like that. The bones that really help you understand whether the organism walked upright or not.
So basically, after this graduate student told Roberto Macchiarelli about this femur, when she was just trying to get help identifying the bone, according to the Guardian article, she got in big trouble by her advisors. Okay? And I'll read a quote from this article.
One of her advisors appeared with a femur in his hand. And this piece, he warned, holding it before her, you forget you ever saw it. Okay? And the idea was kind of that she had leaked information about this very important bone to somebody outside of Michael Brunei's team. And according to the Guardian story, it said the laboratory seemed to close ranks against her. She said, and after her master's, she was made to understand that there was no support for her to take a doctorate. So she kind of got forced out of the lab, okay? So it seemed like people wanted to forget about the femur because years went by and nothing was published about the bone. I mean, it was not until 2020, almost 20 years after this fossil was first reported, that finally there was a paper about the femur. And it was published by critics, people who are on the outside of this team that originally discovered the fossil.
And Machiavelli, in this Guardian article, he basically expresses concerns that Michael Brunet, the original discoverer or the lead of that team that discovered it, that he had hid the femur of this fossil from other researchers because it did not support claims of bipedalism in this species. Now, whether Brunet actually did that or not, I can't say. But I can say that this is what Machiavelli is saying. This is what he believes might be true. And that is why, you know, first of all, he tried to squelch this poor graduate student who leaked information about the femur to another researcher and then took so many years, basically sitting on this bone, not publishing about it, which is very odd. You know, if it's such a great, important bone, you can get some really good papers out of that. You want to publish that.
That is the kind of thing that could potentially go into top scientific journals. But they didn't publish it, so why not? Why were all the secrecy? Why all the controversy? It should just be, okay, there's a femur, let's report it. Shouldn't be a big deal, but, you know, they made a big stink about it. And, you know, methinks thou dost protest too much. That was kind of what was going on here.
[00:32:05] Speaker B: That was Dr. Casey Luskin giving some important background on the field of paleoanthropology and the controversy surrounding the Sahelanthropus tchadensis fossil find.
Don't miss the conclusion to this conversation in a separate episode where Casey will discuss the telling researcher to specimen imbalance that is in the field, the nuance between error and deception in human origins narratives, and the broader implications of the controversy around the Sahelanthropus fossil.
We're grateful to Lenny Esposito and Come Reason Ministries for allowing us to share this conversation here for ID the Future. I'm Andrew McDermott. Thanks for joining us.
[00:32:47] Speaker A: Visit
[email protected] and intelligent design.org this program is Copyright Discovery Institute and recorded by its center for Science and Culture.
