Being Human After Darwin 2 (RJS)

I posted last week on the first part of an essay by Francisco Ayala entitled Being Human After Darwin. Today I am going to discuss the second part of this essay, but first I would like to point to an issue of Perspectives on Science and Christian Faith, the journal of the American Scientific Affiliation (The ASA is a network of Christians in the sciences). The recent issue of PSCF (v. 62 no. 3 2010) is a theme issue: Reading Genesis: The Historicity of Adam and Eve, Genomics, and Evolutionary Science. According to the website the print version is sold out; but several of the articles are available for download on the ASA PSCF Discussion blog. The topics here mesh very well with the book I am currently blogging through “Theology After Darwin (available from of search on author = Berry and title = Theology After Darwin).  I am going to intersperse discussion of the essays in the book and discussion of the articles in the Journal.

The article Genesis and the Genome by Dennis Venema (pp.166-178, access the pdf of the article by clicking on the reference below the abstract) puts more “flesh” on some of the argument that I was making in last Tuesday’s post. In his article Dr. Venema outlines several arguments for common descent, arguments based on gene homology using the gene coding for insulin as an example,  arguments based on spatial organization, including the chromosome 2 example I used in the last post, and arguments based on pseudogenes. Dr. Venema also puts some more detail into the discussion of population size and the question of mitochondrial Eve and Y-chromosomal Adam.  Ancestral population estimates using large data sets and a variety of methods return a size of something like 10,000 individuals for the interbreeding population which became human (homo sapiens). I may come back and post on his paper later in this series – especially if there are questions worth discussion.

Common descent and the discussion of the science of human origins opens the door to the more significant question: If mankind is not the pinnacle and purpose of all creation, what are we? If we evolved in continuity with the animals what makes humans distinctive creatures?

Dr. Ayala’s essay centers in on these questions. To search for answers he considers specifically three transformations, the egg-to-adult transformation, the brain-to-mind transformation, and the ape-to-human transformation. These three transformations according to Dr. Ayala, “define the humanum, that which makes us specifically human.” He suggests that a consideration of these transformations “provide[s] a valid foundation for a religious view of humans as special creatures of God.” (p. 90) He concludes his essay looking at a fourth connection from biology to culture arising from the first three transformations.

The egg-to-adult transformation.The significance of the egg-to-adult transformation lies in the elaborate set of control mechanisms that turn genes on and off allowing differentiation and function. Dr. Ayala outlines some of the complexity involved in this transformation:

A human being consists of one trillion cells of some 300 different kinds, all derived by sequential division from the fertilized egg, a single cell 0.1 millimeters in diameter. The first few cell divisions yield a spherical mass of amorphous cells. Successive divisions are accompanied by the appearance of folds and ridges in the mass of cells and, later on, of the variety of tissues, organs, and limbs characteristic of the human individual. (p. 96-97)

In mammals, insects, and other complex organisms there are control circuits that operate at higher levels than the control circuits that activate and deactivate individual genes. These higher level circuits (such as the so-called homeobox genes) act on sets rather than individual genes. The details of how these sets are controlled, how many control systems there are and how they interact, as well as many other related questions, are what needs to be resolved to elucidate the egg-to-adult transformation. (p. 97)

The key point here is the layered complexity that leads from the information content in a simple cell to the complex functionality of an adult animal – be it a fly or a mammal. It isn’t simply a matter of the gene alone – or even the regulation of individual genes, but the regulation of groups of genes at different times and in different places. To consider the significance of humans we start with the transformation from information to organism. But we need more.

The brain-to-mind transformation. The brain is, Dr. Ayala claims, the most complex and distinctive human organ. Cell differentiation gets us to the brain – but what transforms a brain into a mind? Here Dr. Ayala opens up.

Humans have a very large brain relative to their body size, and a cerebral cortex that is disproportionately large even for their brain size. Abstract thinking, symbolic language, complex social organizations, values and ethics are manifestations of the wondrous capacity of the human brain to gather information about the external world and to integrate that information and react flexibly to what is perceived. (p. 99)

The significance here is that the DNA sequence, according to Dr. Ayala, is not large enough to specify the connections of a human brain. Again there must be a hierarchy of instruction and control. The brain – like the more rudimentary precursors, from light sensitive spots to the response of Paramecium to chemical change – allows information and response.  But it does so much more – allowing creative synthesis.

Human beings have developed the ability to transcend natural selection – the means by which most organisms adapt to changes in the environment. The mind enables a new mode of evolution and development. “Humans, and humans alone, have developed the capacity to adapt to hostile environments by modifying the environments according to the needs of their genes.” (p. 99). The mind, while presumably explicable by scientific means, transcends the chemistry and physics in some significant ways – with a hierarchy leading to curiosity and the ability to understand and control. Rudimentary abilities are seen in animals, from insects to primates, but human flexibility, control, and abstraction is unparalleled.  Humans study the genome and the universe, look for ways to heal and explore.

The ape-to-human transformation. Here we see what Dr. Ayala views as another instance of the human distinctive.  Humans are not “gene machines” contra Dawkins.

In humans, the ‘environment’ takes a new dimension, and becomes the dominant one. Humans manipulate the natural environment so that it fits the nees of their biological make-up; for example, making clothing and houses to live in cold climates. Moreover, the products of human technology – art, science, political institutions, and the like – are dominant features of human environments. (p. 101)

The ape-to-human transformation is centered in the development of the brain. Dr. Ayala notes that genes active in the brain have changed more in humans than chimps, that the fastest evolving genes encode for transcription factors (proteins operating to control gene expression), genes (eg FOXP2) involved in speech. “In an important sense, the most distinctive human features are those expressed in the brain, those that account for the human mind and for human identity.” (p. 103)

From Biology to culture. The three transformations outlined lead, as intimated above, to a fourth transformation – the transformation from biology to culture. What makes us human is not the simple biology and biochemistry – but the development of the brain to the extent that it allows and enables culture. Development and heredity now include a ‘superorganic’ component.

Cultural inheritance makes possible for people what no other organism can accomplish – the cumulative transmission of experience from generation to generation. Animals can learn from experience, but they do not transmit their experiences, their ‘discoveries’ (at least not to any large extent) to the following generations. Animals have individual memory, but they do not have a ‘social memory’. Humans, on the other hand, have developed a culture because they can transmit cumulatively their experiences from generation to generation. (p. 104)

Cultural adaptation has prevailed in mankind over biological adaptation because it is a more rapid mode of adaptation and because it can be directed. A favorable genetic mutation newly arisen in an individual can be transmitted to a sizable part of the human species only through innumerable generations. However, a new scientific discovery or technical achievement can be transmitted to the whole of mankind, potentially at least, in less than one generation. Moreover, whenever a need arises, culture can directly pursue the appropriate changes to meet the challenge.  On the contrary, biological adaptation depends on the accidental availability of a favorable mutation, or of a combination of several mutations, at the time and place where the need arises. (p. 104-105)

Humans are not distinctive because of biology or origin – but because of mind and culture.  We stand on the shoulders of those who came before, not simply in our biological composition, but more importantly and more profoundly in our knowledge, our understanding, and our culture, in the knowledge of good and evil, in the awareness that things could be better. There is a thread in this essay that treads a bit close to a progressive gospel – the idea that we are, of our own making, getting better and better. But I don’t think that this is really the important take-home message. Humans are human collectively and in the context of culture.

What do you think, is Dr. Ayala on to something here? What impact does this, or might this, have on theology?

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  • scotmcknight

    I read a study once on “happiness” that anchored happiness in the frontal lobe’s capacity to ponder the future, to raise levels of expectations (and frustrations when not met), and to live in light of that future. Faith in God in some ways is connected to hope … and that study, after reading yours, makes me wonder if that kind of thinking is a key element in what makes human human.

  • Jason Lee

    This reminds me of something Peter Berger talks about in THE SACRED CANOPY … that we as humans rely to a significantly lesser degree on instincts to guide our behavior; we rely heavily on cultural institutions. These institutions (eg, family rules, polity, religion) vary across place and time, and this variation can explain a large part of the variation in human behavior. This seems to dovetail with the above notion of institutions taking a more dominant role for humans in comparison with the dominant role of instincts for other animals.

    This conversation also seems to dovetail with Christian Smith’s MORAL BELIEVING ANIMALS. Moral culture is a large part of what sets humans apart from other animals. Humans have a strong need to believe big cultural narratives and designate things as right and wrong. Even the non-religious are believers in their own kinds of sacred narratives.

  • Tim


    I completely agree. What differentiates humans from the other animals is not consciousness or altruism, but rather our highly creative and capable mind and culture. This is what allowed us to beat out the far more physically robust Neanderthals and, of course, now dominate this planet. Some people peg this change in our cognitive ability as early as 35,000 years ago, others to 100,000 years back or more. But that change is what made us what we are as a species.

  • John I.

    Evolution assumes the complete plasticity of genetic material in an organism. Hence, by successive gradual modification (losing, gaining, or changing physically expressed attributes) any organism can become anything. It further entails that we could manipulate any other organism until it develops consciousness and morality. Indeed, we could do that far more rapidly than natural evolution because we can dispense with the genetic material removing effects of natural selection. That is, we can preserve any modification in an organism that we want by ensuring that it survives. Finally, it entails that we should modify our own genetic material further; perhaps we should want a brain with a larger frontal lobe, or perhaps we can develop better regulatory systems for our hormones, etc.

    John I.

  • Randy Gabrielse

    If “order of creation” matters at all, I look at Genesis and see a creation that was doing just fine, thank you, without humans until the “sixth day” and I look now and see us exterminating spieces and destroying the planet. I cannot think that we are the “pinnacle” in any way that creation itself “needs” us. I also look to Psalm 104, where humans seem marginal at best to the creation, which makes a nice balanced contrast with the more popular Psalm 8.

    I believe that humans’ role in creation is based in our being made in his image, which has much more to do with our relating to God than our relating to animals, although in almost every way we are one of them.

  • dopderbeck

    Great post. One possible problem with Ayala’s reliance on “mind” and “culture” is that the reductive materialist view of evolution elides these concepts. Neurobiologists claim that their discipline, in conjunction with evolutionary biology, is doing away with the “mind” as anything other than an epiphenomenon. So, I worry that strong reliance on “mind” is just another version of a “God of the gaps” (or “humanity of the gaps”) sort of argument.

  • DRT

    This is one of the best articulations of the difference between man and animal I have read. Thanks.

    But it works both ways. We have the ability to advance our species (and other species) as well as retard. We can create and destroy. We can look to the future and have hope, or look to the future and say, “the rapture will come and it won’t matter”. We have the ability to make the world a better place for man and animal but it does not seem to be the case that we make it that way. At least not yet.

    I still have my theory that “in god’s image” is that we have the ability to create. Implicit in that is also the ability to destroy.

    Given the future of humanity and all of life on earth is at stake here, the last one I want to be in charge is all the men. So from a theology standpoint we should have all the women in charge so that the world may actually get to be a better place.

  • Justin Topp

    Good post. So much to comment on but I’ve got labs to get started. Will comment later…

  • nick gill

    From Josh Graves:

    Humans take center stage in this story. We are the only element of creation which causes God not to say “good” but “very good.” God is most pleased with what God has done by forming man and woman. The word “image”, which in Hebrew is “selem”, is usually understood in terms of essence. That is, humans are like God, in that, we love, care, feel, etc. But, there’s more going on these texts than we acknowledge. It’s probably better to translate the word “image” as “eikon.” The word “humankind” should probably be translated “The Adam” since it refers, in chapter 1, to both male and female. Thus, we might understand the power of Genesis 1 if we read the text in this way (see Scot McKnight’s chart on p. 69 in Blue Parakeet): God creates The Adam. God splits the lonely The Adam into Ish (man) and Ishah (woman). God then brings Ish (man) and Ishah (woman) back together again as one complete flesh. Because just as God is complete in community, so too are humans.

    Mr. and Mrs. Eikon bear God’s image to the rest of the world in mysterious ways. In Ancient Near Eastern creation narratives, “eikon” was royal or kingship language. In the Ancient Near East it was widely believed that a god’s spirit lived in any statue of image of that god, with the result that the image could function as a kind of representative of or substitute for the god wherever it was placed. In the ANE, the king often “stood in the place of” the gods. Therefore Genesis is saying that humans exercise dominion and authority over creation simply because they are human. There’s not one king but many kings who have a high calling to live in shalom with the rest of creation. Kingship gets democratized. Every person who inhabits Planet Earth bears the stamp of royalty. Regardless of race (black, white, yellow, brown, or purple), ethnicity (white, black, Latino, Laotian, or Kurdish) or religion (Christian, Jewish, Buddhist, Muslim, Hindu or Baha’i)—Genesis declares that God’s image is stamped upon every person.

  • pds

    John I. #4,

    Excellent comment. If we accept that Darwinian evolution fully explains our humanity, then there was a point in the past when “humans” were only 85% human, 60% human before that and 45% human before that. In the future some of us will become 105% human, then 120% human. Others may go in the other direction. There is also no basis for concluding that all humans are currently 100% human.

    We have seen this logic play out before . . .

  • pds


    Any comment on the paper discussed over at Telic Thoughts on a very related topic?

    Unfortunately, it has become increasingly clear that most of the mutation load is associated with mutations with very small effects distributed at unpredictable locations over the entire genome, rendering the prospects for long-term management of the human gene pool by genetic counseling highly unlikely for all but perhaps a few hundred key loci underlying debilitating monogenic genetic disorders (such as those focused on in the present study).

    Thus, the preceding observations paint a rather stark picture. At least in highly industrialized societies, the impact of deleterious mutations is accumulating on a time scale that is approximately the same as that for scenarios associated with global warming—perhaps not of great concern over a span of one or two generations, but with very considerable consequences on time scales of tens of generations. Without a reduction in the germline transmission of deleterious mutations, the mean phenotypes of the residents of industrialized nations are likely to be rather different in just two or three centuries, with significant incapacitation at the morphological, physiological, and neurobiological levels.

  • Ray Ingles

    John I – Actually, evolution does not require or assume “the complete plasticity of genetic material in an organism”. I suggest you take a look at “Evolution For Everyone” by David Sloan Wilson where he devotes a chapter or two to that very issue.

    PDS – The boundaries between types aren’t measured in percentages. Is there something that’s 20% sofa and 80% chair? (Can it be 10% loveseat?)

  • rjs


    Predicting forward, especially on something so poorly understood, is precarious. Another inaugural article in PNAS was the one on free will I posted on a while back claiming mankind has no more free will than a bowl of sugar. I’d have to go read the article to have anything more substantive to say though.

    With respect to John I’s point – evolution does not require or assume the complete plasticity of genetic material. Evolution functions within the realm of that which is chemically and physically possible. With respect to what makes us human … this is really a social and metaphysical question – not a biological one. And, I think the root answer is social and religious, not biological. The biology only provides the structure.

    Eugenics was not rooted in chemistry, physics, or evolutionary biology – it was rooted in the social and cultural aspirations of humans for self aggrandizement. And then we get to sin.

  • pds

    RJS #13,

    You said,

    “Eugenics was not rooted in . . . evolutionary biology.”

    You may be a great scientist, but you are simply wrong on this point of history.

    “With respect to what makes us human … this is really a social and metaphysical question – not a biological one.”

    You are parting company with many, many mainstream scientists here. Why?

  • rjs


    I think that those who supported eugenics, like those who supported many forms of racism and ethnocentrism, used science to defend an idea with roots in human nature – in, I think, sinful human nature.

    Christians have also used religion and scripture to defend ideas (including racism and slavery) with roots in sinful human nature.

    Christianity itself is not responsible for the abusive ways in which it has been used, nor is evolutionary biology responsible for the abusive ways in which it has been used.

    We need the gospel for a reason.

  • Justin Topp

    The first transformation, to me, is irrelevant to what it means to be human as it doesn’t speak of our uniqueness in any way. The second and third transformations are relevant, but we must consider that biologically speaking, we’re different in a matter of quantity, not quality. Mind and culture are observed in other animals, just not to the degrees that we see them in humans.

    As to Ayala’s position (or RJS’s summary) on the brain-mind transformation specifically, it doesn’t make sense that the DNA sequence would not be complex enough to specify a mind, again biologically speaking. What else is there? The complexities of our brains arise from the DNA sequence which codes for the RNA and proteins that make us up. Even if we allow for top-down causation (which I absolutely do), that causation will be absolutely dependent upon our DNA.

    Wonderful topic, and one that should give rise to a great discussion. And it shows me that we clearly need a book for the Christian audience on what it means to be human…

  • Barb

    Today is my birthday. I’ve traveled pretty far from the “egg” and hopefully I’m “adult” most of the time. This concept that we remember/count our birthdays seems to be a human trait. (I know some cultures don’t–but I bet they know the stages of development. :).

  • rjs

    Barb, Happy Birthday.


    Ayala says that the DNA isn’t long enough to specify each and every connection and junction – thus the brain must work through a structure of hierarchical controls. This structure of hierarchical control is significant. So – there is enough DNA, but it must function in a complex fashion. (My rough summary without the essay in front of me.)

  • DRT

    Justin @16,

    I too thought there was mainly a difference of quantity, not quality as you said. But I feel the differentiating factor in this exposition is the willful ability for humans to change their future at every level outside of god. They can change their genes, their heredity, the environment for their descendents, virtually everything. That is a difference in quality to me.

    I also started hearing a statistic a couple of years ago where they are saying that the first person to live to 200 (extra-biblical) has probably already been born. My oldest son is saying that he is preparing for a more or less indefinite existance using artificial means of support (mind meld into the computer or whatever).

    Wait a second. Am I on the E.T. thread…..

  • Dennis Venema

    Thanks for the link to that article, RJS. I’ll look forward to your thoughts on it if you decide to blog on it (or to comments from your readers).



  • johnfouadhanna

    I recently read “What Makes Us Human,” which is an anthology on the subject. In this collection, the most common characteristics identified as unique to our humanity are our larger and more complex brains and capacity for language, both of which are cited by Ayala.

    While these and other characteristics are highly relevant and interesting, I would say, as others have on this thread, that our uniqueness and essential humanness is that we are image of God. I would further say that image of God is not based on any particular capability or function. Thus, our humanity is not a function of any thing we possess in and of ourselves but is wholly derived from the one who made and sustains us. To put it in theological terms, we are most basically covenantal beings. In saying this I’m not locating image of God in an immaterial soul or spirit at the expense of the material/physical.

    Tying our humanity to image of God allows for something that the merely descriptive accounts don’t consider. It accounts for the intuitive sense that there’s a way to be human we don’t live up to. This sense is demonstrated in our reflexive reaction to conduct we deem immoral or repulsive: “how could a human being do such a thing?”; “he behaved like an animal”, etc.

  • rjs

    Dennis #20,

    If I’d known about your article when I wrote the first post in this series I would have referenced it heavily. I am sure that the topic will come up again – and I am glad to have this as a resource.

    johnfouadhanna #21,

    To say that we are most basically covenantal beings seems to me to agree that community, social interaction, relationship, culture are key defining characteristics. The biology merely enables.

    But this requires attaching some reality beyond utilitarian chemistry and physics to concepts like good and beauty and purpose. This is where image of God and mission of God and purpose of God all come into the picture. Our humanity is derived solely from God who made and sustains us.

  • pds

    RJS #13,

    You said,

    “With respect to what makes us human … this is really a social and metaphysical question – not a biological one.”

    But your post is all about “Being Human After Darwin.” Ayala seems to disagree with you.

    If “what makes us human” is not a biological question, why would it change “after Darwin”?

  • Ray Ingles

    Note that quantitative differences can engender qualitative differences. While riding in a car, stick your hand out flat, parallel to the ground. Now, slowly change the angle of your hand – you’ll find there’s a transition where the airflow around it goes from more-or-less smooth to turbulent and messy. But all you changed was the angle of your hand.

    Or, you can slowly raise the temperature of ice, and suddenly you have water. Raise it more, and suddenly you get steam. Even though you’ve just smoothly, gradually raised the temperature, at some points the properties changed rapidly and drastically. That’s called a ‘phase transition’.

    Looked at one way, humans are ‘just’ smarter animals. On the other hand, it sure seems to me that a ‘phase transition’ or two happened as intelligence increased… and RJS lists a few of them above.

    You can add souls to this if you like. But it’s possible for people who don’t believe in souls to still think humans are pretty distinct and special.