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Part Two in the Uniquely unique mini-series. When we look for what makes humans unique on this planet, looking at our biology is an obvious first step.


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Part Two in the Uniquely unique mini-series. When we look for what makes humans unique on this planet, looking at our biology is an obvious first step.

Description

When looking for the thing that makes humans unique on this planet, looking at our biology is an obvious first step. In this episode four experts—an anatomist, a geneticist, a paleo-anthropologist and a neurologist—help us look for something about us, in our bodies, cells, or brains, that make us what we are. In the search we end up finding as much continuity with the animal world as we find uniqueness. 

In this new Language of God mini series—Uniquely Unique—Jim is joined by our producer Colin for a deep dive into these questions and more. The quest? To try to come to a better understanding of what it means to be human, to bear the image of God. Along the way, you’ll hear from a variety of experts from a wide range of disciplines, drawing on biology, history, anthropology, philosophy, theology and more to try to make sense of our human identity.

Transcript

Stump: 

Welcome to Language of God. I’m Jim Stump

Hoogerwerf: 

And I’m Colin Hoogerwerf

Stump: 

This is the second episode in our series we’re calling, “Uniquely unique.”

Hoogerwerf: 

And in this episode: 

Various Voices: 

Biology. 

Stump: 

Like last time, Colin and I will be trying to work out some issues related to the question, What does it mean to be human? And in doing so we talk to a number of experts. 

Hoogerwerf: 

And this time we’re leaning into the biologists, and we have a whole new cast of characters. So let’s start by hearing from them. 

Bebej: 

I certainly think that there are aspects of human biology that have contributed to our ways of relating to one another, given us some capacities as a species that God must have seen and said,” okay, that there’s one of my creatures that’s ready.”

Sethupathy: 

To what extent are those features encoded in our biology? I think there’s no doubt that they’re going to be encoded in our biology to some extent. But I think we’re going to find it quite challenging to explain it fully by biology alone. And so I think that this does leave room for us to then question and think about and wrestle with what it means that we were uniquely called to represent and reflect God as image bearers that might be interwoven with our biology, but not sufficiently explained by our biology.

Wall-Scheffler: 

Paleo-anthropologists obviously go back and forth between what it means to be human based on what we can see in the paleontological and archaeological record, and what it means to be human based on our own intuitions about life on earth.

Branco: 

The human brain is particularly good at a few things: language, social relationships, emotional processing, and emotional restraint, goal setting, imagination—the idea that you can picture yourself in the future, or in the past, or in some theoretical setting that would never actually exist, those seem to be particular strengths of the human nervous system that we don’t see anything comparable to it in other species.

Stump: 

We’ll introduce each of these speakers as we go through this tour of the biological human. But first let’s go back to the last episode where we launched this question that we’re asking throughout the series, what does it mean to be human. We came to the conclusion there— Did we come to a conclusion?

Hoogerwerf: 

Maybe provisionally?

Stump: 

Okay, we provisionally concluded contingent on further investigation, that there does seem to be something about humans that is not only unique the way every other creature is unique, but that we are uniquely unique among God’s creatures.

Hoogerwerf: 

We also decided there are two really different ways of looking at this question. One way looks at the human and what it is made of, looking to see if we can identify that uniqueness by distinguishing its composition and abilities. This approach relies heavily on the sciences. The second way does not look to particular traits but looks at the purpose and role of humans in the world. We’ve decided to use David’s Lahti’s language here and call these approaches “earth-up” and “heavens-down.”

Stump:

We discussed some other important concepts in that first episode, like just what a species is and the difference between human and Homo sapiens. We suggest going back and giving that a listen if you haven’t. This episode is really going to dive into the “earth-up” approach and what we know about ourselves biologically. What is a human made of? Is there something in our DNA, in our cells, in the structure of our bodies, in the workings of our brains that makes us who we are, a uniquely unique creature? 

Hoogerwerf: 

Let’s start with our bodies. This seems to be one of the most obvious ways we distinguish ourselves from everything else. It’s what we first see about another organism. If we go back to the zoo example from our last episode, bodies are the first clue when we look around and pick out the human standing in front of the gorilla exhibit or peering through the glass at a Burmese python.

Stump: 

But from the scientists’ point of view, though we look different superficially, our bodies are actually very similar to other creatures. This fact is borne out by how scientists classify us.

Hoogerwerf: 

Ryan Bebej is a professor of anatomy and physiology at Calvin University. Ryan was a guest on our Fossils episode way back in Episode 16. We recently asked him about our place in the animal kingdom.

Bebej: 

Well, I think it’s important to kind of note where humans sit, systematically, compared to other animals. I mean, so we’ve talked about this as being Homo sapiens, for sure, but we belong within this nested set of more inclusive groups, right? So not only are we humans, but we’re hominins as well, that includes chimpanzees, bonobos, and gorillas. Then zooming out a little bit more, we’re hominids, which includes the great apes, that would include orangutans as well. And then we’re primates. That includes monkeys and tarsiers and lemurs and things like that. And we’re mammals, which would include your cat and dog, your horse, and cow, all that good stuff. We’re amniotes. That includes birds and reptiles. We’re tetrapods, which is all four-limbed creatures. And we’re vertebrates, we’re animals with a backbone, and on and on, we can keep doing that. 

Stump: 

This reminds me of a conversation I had with a very earnest student once. I had said something about humans and other animals, and she quickly interjected, “Other? Humans are not animals.” And I said something like, “Uh, we’re not plants!” which may not have been the most helpful response at the time.

Hoogerwerf:  

Yeah, It seems like somewhere along the way we’ve all forgotten that we are animals. It seems like that’s a way we have of trying to emphasize that we’re something more, that we want to be not animal.

Stump:  

Yes, and I think certain theologies have conditioned us to think that we’re something totally different, that we don’t fit onto the animal-vegetable-mineral typology. But I’m afraid we can’t escape our biology.

Hoogerwerf: 

Which means, of course, that we can’t escape the fact that we are animals. 

Stump: 

So Ryan shows that there are different levels of relationships and that our body plans do a pretty good job of showing which creatures we are more closely related to. We look a lot more like primates than we do like the rest of the mammals, and more like squirrels than we do robins. 

Hoogerwerf: 

So we remember Linnaeus from the last episode.

Stump: 

Kingdom, phylum, class, order, family, genus, species?

Hoogerwerf: 

So in this classification, which we just heard about from Ryan, we’re in the animal kingdom. We know this because of similarities we have with the other creatures in the animal kingdom. But you have to have differences too, to be able to separate groups from each other. So what are the characteristics that distinguish us from other creatures?

Bebej: 

When I think of the things that really distinguish humans anatomically from our closest relatives it is mostly in the brain, right, our brain size, different aspects of brain anatomy, which lobes have become elaborated for different things. And even there, we share a lot of traits in our brain with our closest primate kin. And then looking at different aspects of our limbs, right? So we’re bipedal and so you’ve got some primates that would maybe have a semi-erect posture, or one where they can walk on two legs for a reasonable period of time. But nowhere near the level of adaptation that we have for walking on just one pair of limbs. And that frees up our hands, right? That frees up our hands for doing other things. And so I think that many people think that that move to bipedality is what really enabled humans to become very efficient with using tools and things like that as well. I suspect that there are some key differences probably related to our larynx as well. We vocalize in a way that’s different from other primates. But beyond those things, I mean, I think of more— I see a lot of these vestigial features in humans, these sort of carry overs that don’t seem to serve too much of an important function in our body that speak more to common ancestry than they do to human uniqueness at all.

Stump: 

Let’s talk about vestigial traits

Hoogerwerf: 

So these are physical traits we used to have but no longer need. They’re our clues that our ancient ancestors had somewhat different bodies.

Stump: 

Right, things like our wisdom teeth, the appendix, and muscles that move our ears. And even if some of these have taken on other functions for us, they clearly are not doing what they originally did in our ancient ancestors. 

Hoogerwerf: 

Ryan told us about another of these that we’re all familiar with.

Bebej:

Have you ever thought about what goosebumps do? Goosebumps are not particularly important or effective in our bodies compared to what they might be doing in other mammals. So almost every hair on your body has a little band of smooth muscle in the hair follicle that can be stimulated to contract to cause that hair to stand on end. And you think about when goosebumps happen in human life, I think of being cold first. You know, what in the world are goosebumps doing for my body when I’m cold? Well, in another mammal whose body is completely covered in body hair, that hair standing on end actually thickens the insolatory layer, it traps a lot more air between those hairs, which is going to help keep that body heat in. No human I know has enough body hair for that to be effective. Thinking about other times when you get goose bumps, when you’re scared. Why in the world would that happen? Well, again, that’s the sympathetic nervous system kicking in. If you’ve ever seen a cat get startled before you get a sense for how effective this is—the cat looks a little bit bigger, its tail gets bigger, its body gets bigger. And the thought is that when an animal’s frightened, and it gets goosebumps, then it might appear larger and potentially scare off a predator or something like that. And as far as I can tell, none of those are adaptive for human life. Yet, we still respond that same way, even with so little body hair.

Hoogerwerf: 

Ryan isn’t helping us too much in finding some anatomical distinctive that really sets us apart, is he?

Stump: 

More the opposite. It seems to be making the case even stronger for the continuity that humans have with the rest of life on earth, at least from a purely anatomical perspective.

Bebej: 

I mean, when you look at the human skeleton compared to the skeleton of a gorilla or a chimpanzee, I mean, it’s so similar. I mean it’s crazy. I even think how strange it is that in most of the human anatomy courses I’ve taught, we use cats as our model, right? I mean, we use these mammals that aren’t even particularly closely related to primates. But they are still so similar anatomically, that we can learn the same organs, the same tissues, the same bones, the same muscles, and I can highlight, well, here’s how it would look a little bit different in your body but still, the anatomy is just so similar, that really, what sets us apart is hard to sort of pin down if we’re only looking at the anatomy.

Stump: 

We should point out that there really are some anatomical features that only humans have. For instance the arch in our feet (for at least most of us), was a pretty recent innovation evolutionarily, to make bipedality more efficient, as is the curvature in our spines. And our hands do some pretty unique things compared to the other primates.

Hoogerwerf: 

Yeah, but a lot of other species have traits that are unique to their kind. Cuttlefish have chromatophores in their skin that allow them to change color in a fraction of a second and there are lizards who have channels in their skin that allow them to use capillary action to absorb water from tiny ponds in the desert. 

Stump: 

So I guess these anatomical distinctives only point toward the uniqueness of humans, and the uniqueness of everything else. We’re looking for how we might be uniquely unique. And if we’re not going to find it in anatomy, then let’s zoom in a little further.

Hoogerwerf: 

How deep are we going here? Down to the cellular level?

Sethupathy: 

Yeah, it’s not a bad place to start. 

Stump: 

This is Praveen Sethupathy. 

Sethupathy: 

Associate Professor of Biomedical Sciences

Stump: 

Praveen is at Cornell University, and he’s been on the podcast several times before. 

Sethupathy: 

There have been observations for decades and decades, that we and perhaps a few other species, have certain kinds of cells that a lot of other species don’t even have. An example is a specialized cell in the intestine called the Paneth cell, named after the gentleman who identified them.

Stump: 

And it turns out a lot of other mammals like dogs and cats don’t have these kinds of cells at all. 

Hoogerwerf: 

But many other mammals do have them. Monkeys, mice, hamsters, bats, guinea pigs…

Stump: 

Ok, ok. How about another one.

Sethupathy: 

The place where we may end up finding more success is in the brain, unsurprisingly. It has long been known that neurons in the human brain are quite a bit different than neurons in other species that have been studied, not just mice and rats that as you may know, are frequently used for studies of behavior and brain biology. But even monkeys and chimps. In particular, there are these arborous kinds of structures that come out of the main body of a neuron. They’re referred to as dendrites. And they’re substantially longer in humans. And it hasn’t been known for some time whether that really matters whether that is linked in any way to our cognitive capabilities.

Hoogerwerf: 

Ok, so maybe we have some differences in our cells. So then can you say that what it means to be human is to have long dendrites?

Sethupathy: 

So there is this natural tendency to want to look to human cells as a way to, you know, define what it means to be human. But, you know, one of the most, I think, kind of stunning discoveries in the field of human biology, in the last couple of decades, is that our bodies, as we think of them, are home to actually tens of trillions of microorganisms. Most of them are bacteria, but there are other kinds of tiny organisms in there as well. And this is really a profound number if you stop and think about it. Because what this means is that slightly more—and this is the best estimate we have at the moment—slightly more than half of the cells in the human body aren’t human at all. Right? They’re actually bacterial.

Stump: 

OK, this is wild. When we look at the cellular level of our bodies, what we find is that most of the cells we thought were us, aren’t even human?

Hoogerwerf: 

Yeah, this really stretches my idea of what I am. How do we even define what is us? I want to look at myself as if I’m all human, but here I learn that inside of me is a whole ecosystem of creatures, interacting. 

Stump: 

And it’s not like they’re just along for the ride. I couldn’t function without them. They are a necessary part of me.

Hoogerwerf: 

Right. What we are includes all those other creatures. 

Stump: 

So can we find anything to help us at an even deeper level? Let’s zoom in further.

Sethupathy: 

Yeah, the DNA has actually been again, it’s a very sensible place to start and to ask this question. But what has been remarkable to most biologists studying DNA is just how similar the DNA is, with respect to other species, and not just chimp and monkey or even mouse. But according to some measures of calculation, you know, we share 20% of our DNA with a certain kind of plant.

Stump: 

DNA is the basic building block for all living things. And we often hear people talking about this issue of just how much we share with chimps or dogs or oak trees, as though that specific number says something really important about our identity.

Hoogerwerf: 

So when I type into google “how much DNA do humans share with…” the first thing that pops up is bananas. And it suggests that we share a significant amount of our DNA. But it looks like that number varies widely on whether you’re looking at genes we share or individual sequences of nucleotides.

Stump: 

We asked Praveen about these numbers and found out that it really hinges on what objects you’re counting, but that this doesn’t take away from the more important point, which is that very small differences in DNA can lead to remarkable changes.

Sethupathy: 

So I’ll points one out, and that is the identification of what are known as HARs or H-A-Rs. And these refer to human accelerated regions. These are regions of our genome—they’re the minority of our genome, a very small portion—however, if you look at those portions, these HARs, what you’ll find is that there’s been a rapid kind of change, and a selection for certain of those changes in these HARs that make them look quite different at the sequence level than even chimps, our closest relative, and certainly gorillas and monkeys, too. There’s something about those regions where there’s been a rapid evolution, if you will, compared to most of the rest of the genome when you compare to our close cousins.

Stump: 

These Human Accelerated Regions are pretty recent discoveries, and it will be interesting to see where that research goes. But I’m not sure they will ultimately show a human uniqueness to our DNA of the kind we’re looking for.

Hoogerwerf: 

Right. There are sections of our DNA that are unique to us, but we have a similar problem as we did at the cellular level, where there is a bunch of our DNA that is littered with viral fragments. So when we try to define ourselves by our genetic code, we are going to find that we are partially virus.

Sethupathy: 

The further and further we dig into biology to try to define human uniqueness, the murkier and murkier it becomes because we realize that there is a profound kind of symbiosis at the DNA level, at the cellular level, that we have with all kinds of other species that we tend to think are completely unlike us, right? So you mentioned viruses and bacteria, but even you know, fungi and other archaea. It’s really, really profound to note that our physiology and our biology are not just intermingled with those of other organisms, but often depend on the proper functioning of those other organisms living inside us, right? And so I do think that that is one of the most powerful things to consider when using biology alone to try to define human uniqueness. 

[musical interlude]

BioLogos:

Hi Language of God listeners. Here at BioLogos we think that asking questions is a worthwhile part of any faith journey. We hope this podcast helps you to think through long held questions and consider new ones but you probably have other questions we haven’t covered yet. That’s why we want to take this quick break to tell you about the common questions page on our website. You’ll find questions like “How could humans have evolved and still be in the image of god,” “how should we interpret the Genesis flood account?” and “What created God?” Each with thoughtful and in depth answers written in collaboration by scientists, biblical scholars and other experts. Just go to biologos.org and click the common questions tab at the top of the page. Back to the show!

Stump: 

We’ve so far been looking at humans as they are today—which is homo sapiens. But we Homo sapiens have not always looked like we do now. Let’s go back in time, around 10 million years ago, when our ancestor pool was also the ancestor pool of today’s chimpanzees. Can we find something in their bodies and in their biology which might give us a clue to what changed along the way to allow us to become the kind of creatures we are today?

Hoogerwerf: 

Do we even know what those common ancestors looked like? 

Wall-Scheffler: 

I think right now, our assessment of the last common ancestor is an arboreal biped, so a creature that spends a lot of time on two feet, but in the trees, not anything like what a living chimpanzee looks like, and not what a living human looks like. And one of the things that we think is quite important for our own lineage is taking that bipedality and coming down to the ground.

Hoogerwerf: 

Can you say your name and your title for us?

Wall-Scheffler: 

Yeah, absolutely. I am Cara Wall Scheffler, and I am Professor and Chair of the Department of Biology at Seattle Pacific University.

Stump: 

Ok, so we’ve got these ancestors who aren’t particularly human yet, but we have to remember they aren’t what today’s apes are either. So what happens next?

Wall-Scheffler: 

So most people would say that one of the really key things that happens at this transition is our foot. The best skeletal remains of something last common ancestor-like continued to have an opposable big toe. And we don’t do a lot of grasping with our feet, unless you don’t have arms and you really need to develop that sort of dexterity, some humans can do that. But as a general rule, we have a big toe, a hallux, in line with the rest of our foot. And it’s quite robust and strong, and we use our foot as propulsion against the ground. And so that’s a pretty major difference as we move from being more arboreal to being more terrestrial.

Hoogerwerf: 

So I have to say, I really love this idea that maybe what makes us human is the ground itself. We come down from the trees and we now have to become a creature that is familiar with the soil. That same soil from Genesis, right, which in the biblical account is what we are made of. 

Stump: 

And being on the ground really does some important things. Cara’s speciality is in the development of walking and load carrying. Being on the ground means that now we are walking between places with patchy resources and we have to carry our things in a different way. And carry our children.  

Wall-Scheffler: 

So now we very quickly start thinking about tool use, we very quickly start thinking about carrying kids and goods and tools, food resources and tools. We very quickly start thinking about whether or not you need any other individuals to walk with you between patchy resources. And here are some of the data involved, right? We have footprints of individuals walking together, we have footprints of little little bipeds hopping in the steps of the big bipeds and then being potentially picked up.

Hoogerwerf: 

There are a lot of other changes happening at this time too. Changes to the structure of the knee and changes to the pelvis. 

Stump: 

And as Ryan mentioned earlier, our hands are now free, and so the hands start to change and adapt, from being suited to swinging on branches to grasping and manipulating objects.

Hoogerwerf: 

This is an interesting transition to think about, then, from the anatomical changes to what behaviors came about as a result of them. We talked in the first episode a bit about the difference between anatomically modern and behaviorally modern humans. And there has been a traditional school of thought that there was a long gap—a couple of hundred thousand years—from when our ancestors were anatomically modern, until they became behaviorally modern.

Stump: 

But Cara sounds like she’s part of the newer perspective on this that doesn’t think there was much of a delay.

Wall-Scheffler: 

I think, at the moment, 2021, there is a stronger group of evidence that once you get anatomically modern humans you also have behaviorally modern humans, and that we see modernity emerge simultaneously, with body and brain.

Stump: 

The thinking now is that we’ve simply been the victims of a sampling error, and that the kinds of evidence that we discover in Europe from 60k years ago, just didn’t survive in the hot, wet climates of Africa 250 thousand years ago. But now we are starting to find hints of that kind of evidence.

Hoogerwerf: 

The thought is, that once you find anatomically modern skeletons, you should find evidence of modern behavior, provided that that kind of evidence would survive as fossils. And paleoanthropologists have a really specific definition of what an anatomically modern human skeleton looks like.

Wall-Scheffler: 

So paleontological record, what makes us human: we have a chin, we have a bowl shaped pelvis. And we have a large frontal lobe. That’s the skeletal evidence of anatomically modern humans. 

Hoogerwerf: 

We have all these traits. A chin. A bowl shaped pelvis. But what we really want to know is, once you have a chin, then are you going to get imagination and creativity and large societies and computers? If you have those traits do you get the rest of what makes us human?

Stump: 

I think the answer to that is, no. There is something else going on, at a level above the anatomy itself. There is language and other kinds of symbolism, and culture and morality that are so important for our lives today.

Wall-Scheffler: 

It sort of pushes what makes, anatomically, humans so remarkable, all the more into their own space, because the sort of the domino effect is not only related to resources, it can’t be because Neanderthals have sort of the masterful ability to acquire resources, but they don’t then develop the communities and the symbolism that we develop. And so there has to be something else that’s happening in our particular species and the emergence of us that still needs to be explained.

Hoogerwerf: 

We’ll talk about those things in more detail in the next episode. But we have to say, don’t we, that our brains are pretty important for facilitating those?

Bebej: 

I think that the ability of humans to relate to one another, to the world around them, and to God is something that it probably is necessary for humans to be able to fulfill this calling that we have. Where that comes from biologically, I think is probably more related to what’s happening in our brain than probably anything else.

Hoogerwerf: 

That was Ryan again, the anatomist. We’ve also talked to a microbiologist and a paleoanthropologist, and all of them have mentioned the brain. 

Stump: 

Sounds like this is an important part of us to explore a bit more. What can we say about the brain?

Branco:

Around three pounds exists between our ears, has two big lobes, kind of lumpy and wrinkly.

Hoogerwerf: 

This must be our brain expert. 

Branco: 

My name is Dr. Rachel Branco.

Stump: 

Rachel is a professor at the University of Notre Dame.

Branco: 

So my particular focus is on the chemistry and biochemistry of the nervous system. 

Stump: 

And one of the first things she pointed out to us is that the brain is not just that three pounds between our ears. The brain is a part of a much larger system, the nervous system. 

Branco: 

At its most basic function, the nervous system exists to take in information, to integrate and process that information, and to produce an appropriate response.

Hoogerwerf: 

But the brain is quite a bit more complicated than this and it might make sense to give just a quick refresher on what’s actually going on inside our heads. 

Branco:

So the basic unit of the nervous system is a neuron. It’s a specialized type of cell that is really good at passing information, which makes sense, because the whole point of the nervous system is an information processing system, organ. 

Hoogerwerf: 

Basically, a neuron will receive a signal from the outside and that signal is passed down the length of a neuron and then to another neuron. So take sight for example. The signal received from the outside is a wavelength of light. 

Branco: 

So this signal is going in one neuron and another neuron in one neuron out another neuron, but the way in which those neurons are communicating with each other, and literally spatially arranged—so which neurons are connected to which other neurons—produces a higher level understanding than the simple wavelength of light. And that’s happening as this information is bouncing literally between one neuron and then it fans out to multiple other neurons that are picking up this signal.

Hoogerwerf: 

As you zoom out from the individual neurons, you start to see a neural network take shape. 

Branco: 

We can add complexity not just by spatial arrangement of neurons connecting one neuron to many neurons, but also what type of chemical signal is being carried between the two neurons. So that chemical signal is called a neurotransmitter. And you very quickly get into different types of neurotransmitters being able to add nuance or another layer of complexity to the way that the signal is processed to the brain.

Hoogerwerf: 

One of the big brain discoveries in the last century is that different parts of our brains are specialized for specific functions. 

Stump: 

It is our brain that allows us to understand and interact with the world. That’s true of every creature. But when we’re looking for what it is that makes us distinctive or unique creatures, it seems like looking to the brain might be a good place to find whatever it is that we have. 

Hoogerwerf: 

So what is different about our brains, than other brains? 

Branco: 

So the areas related to language, emotional processing, reason, and goal setting are particularly developed in humans. So, and what I mean by that is, we’re talking about something called the neocortex, which is the outermost layer of the brain. It’s called cortex, that’s the, I think, Greek word for bark, because it’s literally like a layer of neurons that is on the outermost part of the brain. And it’s called the neocortex because evolutionarily, it’s one of the most recently developed parts of the brain. And our cortex in humans in the areas of language, memory, social functioning, emotional functioning, is overdeveloped compared to other animals.

Stump: 

So certain areas of our brains have really taken off, and many of these areas are related to some of the behaviors we have which seem to be distinctive — having a developed neocortex. It might be tempting to point to these as our uniquely unique characteristics.

Hoogerwerf: 

But… having one or more areas of the brain that really takes off is not unique to humans. Other animals have parts of their brains that are more developed than ours.

Branco:  

So for example, mice have a whole part of the cortex that we don’t have called the barrel cortex, which is devoted to sensory information from their whiskers. Birds have a more complex cerebellum, which helps them orient themselves in three dimensional space during flight. So it’s not like, oh, humans are the only species that took a particular skill and really ran with it in terms of the nervous system, anatomy and function. So, yeah, you asked this question, how are our brains similar or different to other species and overwhelming our brains are really similar to other nervous systems.

Hoogerwerf: 

But is there something else besides our brains? There’s a long tradition of thinking that our thinking is not a function of the three pounds between our ears. 

Branco: 

So different people have tried to, you know, pin this down in the brain for centuries. So, looking at the seed of consciousness, Originally, it was taught the pineal gland, which was the seed of consciousness, we know pineal glands, mostly related to hormone stuff, it’s not, it’s not that glowing, orb we’re looking for in the human brain.

Hoogerwerf: 

So this search for something besides our brains comes from the idea that our minds are totally separate from our bodies, that our minds might actually exist outside of or distinct from our bodies.

Stump: 

Philosophers have called this mind-body dualism. It has had its extreme forms in people like Descartes, and there’s an obvious theological motivation for this, because as Christians we believe that I—this same person, Jim Stump—can exist even after my body (including my brain) has died and decomposed. And it’s not entirely clear that a bodily resurrection solves this problem. It’s easier in some respects to just say there is something else, something immaterial thing that accounts for my continued existence.

Hoogerwerf: 

That mind-body dualism has fallen on pretty difficult times in the last century. Brain science has shown the correlations between different areas of our brains and the kinds of thinking that had once been assumed to be what an immaterial mind does.

Stump: 

Of course it needs to be said that neuroscientists have not remotely been able to explain how consciousness arises from brains, and some people think that we’ll never be able to do that. But in this episode we’re looking at biology, and it remains that biologically speaking our brains are very, very similar to other animals’ brains.

Branco:

If you, you know, cut out a cubic inch of human brain and a cubic inch of sheep brain. No one would be able to say which one is which, just by…

Stump:  

Seriously?

Branco: 

No, I mean, unless you picked a part of the brain that has a particular gross neuroanatomy, that’s, you know, visually recognizable, or if you could do genetic tests, but in terms of how the neurons work, the general areas of the brain, overwhelmingly similar, overwhelmingly similar.

 [musical interlude]

Hoogerwerf: 

So where do things stand with our quest?

Stump: 

Well, there’s no denying that to answer the question, What does it mean to be human, we have to take into account our biology. It is part of what we are, it gives us certain abilities.

Hoogerwerf: 

And of course that is true of all creatures. The bigger question is whether biology points to something more about humans that really sets us apart.

Stump: 

Doesn’t seem like biology alone is going to do that for us.

Hoogerwerf: 

And that’s depressing to you?

Stump: 

Kinda… I mean I’ve been hugely shaped by the theological tradition that recognizes humans as something special among all the creatures—not just different in the way that everything is different and unique, but more than that.

Hoogerwerf: 

Uniquely unique?

Stump: 

Yes!

Hoogerwerf: 

But you’re still not sure what that is?

Stump: 

No, it continues to be just a placeholder, I guess, for that middle ground attempting to hold in tension the insights between recognizing our continuity with other creatures on the one side, and the discontinuity and exceptionalism of humans as set apart on the other side. 

Hoogerwerf: 

Scripture itself seems to reflect that tension doesn’t it?

Stump: 

Yes. The human authors of Scripture span more than 1000 years, and different cultures, so you can expect some range of views there. And of course there is the point about humans being something special, created in God’s image for a special role. But to be fair, there are other voices in the Bible about the nature of humans that sound more like what we’ve found from the biologists in this episode. Ecclesiastes is kind of like the problem child of Scripture in some respects, and it’s not exactly an upper. But there it is in the canon, and we shouldn’t ignore it. The main voice of the book is called the teacher, and in chapter 3 he says, “I said in my heart with regard to human beings that God is testing them to show that they are but animals. For the fate of humans and the fate of animals is the same; as one dies, so dies the other. They all have the same breath, and humans have no advantage over the animals; for all is vanity. All go to one place; all are from the dust and all turn to dust again” (3:18-20).

Hoogerwerf: 

Hmm. “We are but animals.” It sure seems like we’re more drawn to the verses that tell us about how special we are.

Stump: 

Yes, not a lot of sermons taken from that passage. We’ll hear from other voices in Scripture in future episodes in this series.

Hoogerwerf: 

But let’s end this episode with hearing one more time from each of our experts.

Branco: 

What we know is that you can’t crack open a human brain, there will not be like a glowing orb of human reason inside of a human brain. You know, there’s not like, some magical part of the brain that is conferring, you know, a soul or something. So, we can debate about whether this is a problem of degrees, or a problem of a completely new thing, because humans are extraordinarily different from our animal counterparts even though we share much of the same neuroanatomy.

Wall-Scheffler: 

I think that the similarities that we see, for example, between Neanderthals and Homo sapiens, that those similarities make the differences all the more striking, because you can have a mental picture of the tool you want to create, which is a pretty big step. And you can have some amount of observations of nature, so that you can hunt and acquire very difficult to catch organisms. But that does not then necessitate the move towards imagination. It definitely does not necessitate the move towards complex family structures and long distance transport of ideas. It definitely does not translate to cultural distinctives that are consistent across both time and space.

Bebej: 

And so I think part of what makes us human certainly arises from our biology but it’s not all of it. I mean, they’re there. I think getting that image from God is something that goes well beyond our biology. And I think that that’s really for me what it means to be human. But it’s, I also recognize that there’s aspects of our biology that made us ready for that, in some sense.

Sethupathy: 

I think we have a tendency to think that we’re kind of, we’re kind of the end all be all, but then when we consider that our very breath may be dependent on bacteria—bacteria inside us, and by the way, bacteria outside of us too—that I think it is extraordinarily humbling and makes us realize that we are part of an ecosystem where, biologically speaking, one is not given, one sort of species or organism is not really given the edge over another. Right? We see this in the germ war between bacteria and viruses, but we see it also in the cooperation between all kinds of different species, such as bacteria and our own human cells. So there’s this interdependence that we can’t get away from that I think actually prompts us to look outside of biology, ultimately, for where this uniqueness that we still feel like we might have comes from.

Hoogerwerf: 

On the next episode, we will take Praveen’s advice here and begin to look outside of biology, specifically at some of our behaviors and some of the other things that we do, which seem to be distinct to our species. 

Stump: 

Well I think I’m sensing that all of the bacterial cells in me are anxious to hear whether they’ve attached themselves to something uniquely unique! So we’d better get to it.

Hoogerwerf: 

See you in a week.

[musical interlude]

Hoogerwerf:

Language of God is produced by BioLogos. It has been funded in part by the John Templeton Foundation and more than 300 individuals who donated to our crowdfunding campaign. Language of God is produced and mixed by Colin Hoogerwerf. That’s me. Our theme song is by Breakmaster Cylinder. We are produced out of the remote workspaces and homes of BioLogos staff in Grand Rapids, Michigan.

If you have questions or want to join in a conversation about this episode find a link in the show notes for the BioLogos forum. Find more episodes of Language of God on your favorite podcast app or at our website, biologos.org, where you will also find tons of great articles and resources on faith and science. Thanks for listening. 


Featured guests

Ryan Bebej

Ryan Bebej

Ryan Bebej is a professor in the Department of Biology at Calvin University, where he was selected as professor of the year in 2017. He earned his Ph.D. in ecology and evolutionary biology with a focus in paleontology from the University of Michigan. His research focuses on the evolution of aquatic mammals from terrestrial ancestors, including cetaceans (whales, dolphins, and porpoises) and pinnipeds (seals, sea lions, and walruses). He is especially interested in the earliest stages of these large-scale evolutionary transitions and the anatomical modifications that facilitate changes in swimming mode. He has excavated skeletons of fossil whales at Wadi Al-Hitan, a UNESCO World Heritage Site in Egypt’s western desert, and he routinely spends time working in collections at world-renowned museums. Ryan is also deeply interested in the relationship between science and Christian faith. In addition to being a member of BioLogos Voices since 2016, he has been a Scholarship and Christianity in Oxford (SCIO) visiting scholar in science and religion and a participant in SCIO's Bridging the Two Cultures of Science and the Humanities II program. When he isn’t working, he loves spending time with his wife and two sons, playing German tabletop games, and rooting for the Michigan Wolverines and St. Louis Cardinals.
Praveen Sethupathy

Praveen Sethupathy

Praveen is a Professor of Biomedical Sciences and Director of the Center for Vertebrate Genomics at Cornell University, where he directs a research lab focused on genome-scale and molecular approaches to understand human health and disease. He received his BA degree from Cornell University and his PhD in Genomics from the University of Pennsylvania. After completing a post-doctoral fellowship at the National Human Genome Research Institute under the mentorship of Dr. Francis Collins, he moved in 2011 to the University of North Carolina at Chapel Hill as an Assistant Professor in the Department of Genetics. The same year he was selected by Genome Technology as one of the nation’s top 25 rising young investigators in genomics. In 2017, he returned to Cornell University as an Associate Professor and was promoted to Full Professor in 2022. Praveen has authored over 125 peer-reviewed publications and has served as a reviewer for 50 different scientific journals. Recent honors include the prestigious American Diabetes Association Pathway To Stop Diabetes Research Accelerator and the Boehringer Ingelheim Research Mentor Award. Praveen has been an invited speaker for the Veritas Forum, has served on the advisory board for the AAAS Dialogue on Science, Ethics, and Religion, and serves on the Board of Directors for BioLogos. He lives in Brooktondale, NY with his wife and three children.
wall scheffler cara

Cara Wall-Scheffler

Cara Wall-Scheffler is Professor and Co-Chair of Biology at Seattle Pacific. Her research focuses on the evolution of human sexual dimorphism, particularly in the context of balancing the pressures of thermoregulation and long-distance locomotion. Her work shows very clearly that different selection pressures have acted on men and women, and that women in particular have a rare (among mammals) ability to work both efficiently and economically when carrying loads.

rachel branco

Rachel Branco

Rachel Branco is an Assistant Teaching Professor at University of Notre Dame in the Department of Chemistry and Biochemistry. She studied synaptic mechanisms of addiction during a Fulbright Scholarship in the Netherlands, then went on to earn a PhD in Neuroscience from Emory University, where she studied how presynaptic monoamine signaling influences risk of psychiatric disease. Now, she is an advisor and instructor for the Neuroscience and Behavior program at Notre Dame, where she teaches courses on the biochemistry of the nervous system. Rachel is a passionate educator who believes that an understanding of neuroscience helps teach empathy, understanding, and hope.


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