Why I Don’t Think I’m a Darwinian Anymore

Yesterday (4 September 2017), I appeared on the Janet Mefferd Today show, to be interviewed about Purpose and Desire (one week from the official release date, and alas the end of the substantial pre-order discount!). It was a wide-ranging interview, a lot of fun. Toward the end of the interview, Janet asked me what I thought the long-term implications for acceptance of Darwinism were. In response, I told her that, after many years of being a quite staunch Darwinist, as a result of writing this book, I don’t think I’m a Darwinian anymore.

Some immediate disclaimers, in anticipation of the reflexive distortions that are likely to arise. I’m still a staunch evolutionist: I just no longer find the conventional Darwinian explanation for evolution to be plausible. I’m also not coming out in favor of Intelligent Design Theory (IDT). I will have more to say about that topic in future posts, no doubt. Finally, I am not abandoning modern Darwinism in favor of a form of natural theology.

Rather, I just don’t think the modern form of Darwinism—gene selectionism, at the heart of it—explains very much that is important. That we think it does explain much is more a reflection of how modern Darwinism has distorted the power and nature of the gene. Our prevailing assumption has long been the gene as specifier—of form, of function, of behavior, etc.

Rather, our evolving understanding of the relationship between sequence code in DNA and hereditary memory, how the physiology adaptive experience feeds back onto that code and defines new genes on the fly, of the vast array of different types of hereditary memory, has convinced me that sequence code in DNA is the lagging indicator of the evolutionary process, rather than its driver. In short, sequence code memory is more of a participant in the evolutionary process rather than its driver. What drives life forward through time is the striving inherent in homeostasis: life is always seeking new ways to exploit the streams of matter and energy that permeate the world. It is the genes (whatever they are) that fit themselves to that striving rather than the other way round.


Purpose and Desire Book Launch

I am now coming to the end of a wonderful eight month sabbatical in southern Africa, which I divided between Namibia and a resident fellowship at the Stellenbosch Institute for Advanced Study (STIAS). While at STIAS, I put the finishing touches on Purpose and Desire as it made its journey from manuscript to book.

One of the wonderful things that STIAS did for me was to host a book launch / discussion of the book. Prof Hendrik Geyer, Director of STIAS, introduced me, I did a couple of readings, and Prof Jannie Hofmeyr, of the Center for Complex Systems in Transition, led a stimulating discussion.

Below are a few pictures of the event, courtesy of Christoff Pauw, Program Director at STIAS:


Cognition and evolution in social insects

Some articles recently came into my news feed that illustrate nicely the dilemma of cognition, genes and social evolution.

Two articles come from two groups of researchers which were examining the genetics of brain development in ants. They used an advanced gene-editing technique called CRISPR to create a lineage of ants that carried a mutated and non-functional version of the gene orco, which encodes for a receptor for the odorant molecules, called pheromones, that ants and other social insects employ to communicate with one another. In insect societies, these pheromones play an important role in organizing the social life of the colony.

In the ants with the mutated receptors, the social organization of the ant colonies was disastrously disrupted. No surprise there: the mutation effectively blinded the ants to all the signals from their nestmates that allowed them to organize themselves into a superorganism. They also found that the mutated ants suffered degradation of those regions of the ant brain that process those pheromone signals. Again, no real surprise there: it is common for the parts of the brain that process sensory signals to need input from sensors to develop properly. In animals blinded from birth, for example, those parts of the brain that process visual sensory information differ substantially from the brains of animals that have normal eyes.

What was surprising to me is what the researchers conclude. To quote from their abstract: “The development of genetics in [these ants] establishes this ant species as a model organism to study the complexity of eusociality.” Let me translate a bit. “Eusociality” refers to the complex social systems found in the ants, bees and termites. The evolution of eusociality and the superorganism is a big problem in evolutionary biology. These researchers are taking the position that we can understand the evolution of these complex societies as a matter of genetics.

Really? I don’t begrudge them the hope, but what can genetically blinded ants tell us about the evolution of sociality? Color me doubtful, I guess.

Fueling my doubt is an accompanying article (not a paper yet, this is from a news article (link below) about a group of European researchers.) about how the pattern of ant pheromones varies in related lineages of ants. Some background: the chemical communication among ants involves semi-waxy molecules that are secreted onto the ant’s exoskeleton, called cuticular hydrocarbons (CHCs). These CHCs are smelled / tasted by other ants, and serve the ongoing communication amongst nestmates. The chemical communication among ants is extraordinarily rich: ants sense not only individual molecules, but mixtures of molecules. Think of it as a kind of painting. You can make up millions of colors by various combinations of just four primary colors (Cyan, Magenta, Yellow, Black: the CMYK color profile). In the same way, ants can use just a few types of CHC to paint themselves with an extraordinary range of pheromone “colors.”

These researchers were curious how closely related ant species could distinguish themselves from one another, using their different patterns of CHCs. They expected that the diversity of CHC patterns would closely reflect their genetic lineage. In other words, they expected that a species “pheromone color” would mark lineages quite closely, as if species A was red, species B blue, species C yellow and so forth.

What they found instead was a much richer pheromone coloration that reflected adaptive conditions. As if, for example, species A would paint itself red in some situations, orange in other circumstances, mauve in still others. In other words, pheromone coloration communicated both species identity, and adaptation.

Returning then to our mutant ants, what could a mutation that effectively blinded ants to this extraordinarily rich sensory landscape tell us about the evolution of a complex phenomenon like sociality? Again, color me skeptical.

I wrote about this problem in Purpose and Desire, and phrased it this way. The notion of sociality as an expression of “sociality genes” cannot really tell us much about the evolution of these remarkable social systems. What makes more sense is to treat the evolution of complex societies as an expression of cognition, which is what really drives lineages forward in time: evolution.


Trible, W., L. Olivos-Cisneros, et al. Orco Mutagenesis Causes Loss of Antennal Lobe Glomeruli and Impaired Social Behavior in Ants. Cell 170(4): 727-735.e710.

Yan, H., C. Opachaloemphan, et al. An Engineered orco Mutation Produces Aberrant Social Behavior and Defective Neural Development in Ants. Cell 170(4): 736-747.e739.


Extended Evolutionary Synthesis? Or?

The “Modern Synthesis” is what we now call the form of Darwinism that emerged in the aftermath of the “Crisis of Darwinism.” That crisis was precipitated by Thomas Hunt Morgan, of fruit fly genetics fame, that essentially drove a stake through the heart of Darwinism. His theory of evolution, called mutationism, asserted that evolution could only proceed through gene mutations. Natural selection and adaptation could play no role in Morgan’s gene-centered world.

The Modern Synthesis is supposed to have rescued Darwinism from Morgan’s mutationism. Its originators (Ronald Fisher, Sewall Wright and J B S Haldane) showed how natural selection could work in Morgan’s gene-centered world, but they did so in a way that left mutationism intact at its heart. The Modern Synthesis is often called Neodarwinism, but it’s hard to defend that term, because gene mutationism still sits at the heart of it.

What’s missing, as I argue in Purpose and Desire, is a coherent theory of adaptation: the tendency of living systems toward “apt” form. Adaptation has long been a problematic concept for Darwinism. It is the essential link between the living organism and natural selection. Yet, adaptation is a fundamentally a phenomenon of cognition and intentionality, a no-no in the mechanistic presumptions of modern Darwinism. Much of the history of evolutionary thought has been spent in trying to wriggle out of that inconvenient conundrum. I lay it all out in Purpose and Desire if you want to learn more.

Right now, the hot topic is the so-called Extended Evolutionary Synthesis (EES) which is supposed to account for this problem. The motivation is sound: the Modern Synthesis is a genetic theory of evolution, where actual evolution is a story about the evolution of form (dogs look different from wolves, Equus looks different from Eohippus, etc.). This is where adaptation should be coming in, but doesn’t. Look at these two Venn diagrams (from a forthcoming paper by Emanuele Serrelli) showing two different representations of the EES (from the same author, incidentally). The MS is the center set and the EES is everything surrounding it.

EES SerelliTwo impressions:

  • The EES certainly encompasses a lot of things it should, things like epigenetics, niche construction, natural history. So, A for effort. But what’s the relationship between all of them? It’s a bit of a grab-bag.
  • What’s missing from all this is ADAPTATION! Why? Because it’s inconveniently purposeful!

Serrelli E (2017). Metascientific views: Challenge and opportunity for philosophy of biology in practice. Acta Philosophica 26(1): 65-82.


Purpose and Desire is available from 12 September 2017. It is available at a substantial discount for pre-order now. See purposeanddesirebook.com for more detail

Baby fish working out

An interesting paper has just come out in the Proceedings of the Royal Society by Hu and Albertson (Hu, Y. and R. C. Albertson (2017). Baby fish working out: an epigenetic source of adaptive variation in the cichlid jaw. Proceedings of the Royal Society B: Biological Sciences 284). It illustrates in a nice way the point I am trying to make in Purpose and Desire: gene selectionism has failed as a coherent theory of evolution.

The problem they tackle is the diversity of cichlid fishes. These occur in great variety in the Great Lakes of Africa, Lake Malawi in this case, and they have long been a case study in evolutionary diversification. The Great Lakes contain dozens of species that live in a variety of ways. The trouble is there is not sufficient genetic diversity to account for the diversity in form and function among these fishes.

Hu and Albertson focused on the development of the jaw structure, which is quite diverse among the cichlids. Diverse jaw structure indicates diverse ways these fish can feed, and hence the ecological niches they occupy (the problematic concept of the ecological niche will come up at some time soon). The standard way this diversity is explained is genetic diversification. Here’s the logic. Jaw form is specified by the genes that determine jaw form. As competition among fishes drives fish to exploit one habitat or another, natural selection will favor genes that determine apt jaw structure. The logic falls because there is not sufficient diversity in the genes involved in jaw formation to account for the variation in jaw morphology. Let’s not even bring up how a particular sequence of nucleotides translates into a particular jaw structure.

The remarkable thing that Hu and Albertson found was that the fish embryos “train” their jaws to a particular shape. At the stage of embryonic development, where the jaws begin to mineralize—that is transition from cartilage to bone—the embryo begins to exercise its jaws. This puts the developing jaws under mechanical strain, which affects the pattern of jaw mineralization, which ultimately translates into a particular jaw morphology.

As I wrote in The Tinkerer’s Accomplice in 2007, this is a classic example of homeostasis in action. Bones are governed by homeostasis of strain, and are structured to normalize mechanical strain throughout. By exercising the jaws in this way, these fishes are actively shaping their jaws. Indeed, they are shaping them intentionally (I am defining intentionality very broadly, of course. You can read why I think doing so is justified in The Tinkerer’s Accomplice).

And this is the point I have tried to make in Purpose and Desire. Adaptation, in this instance a form of jaw that is apt for a particular style of feeding, is driven more by intentionality than it is by possessing “apt function genes.” And if adaptation is to play any role at all in Darwinian evolution, it has to be solidly grounded in physiology, not genetics.


Welcome to my blog. This is a forum where I can comment on evolution, physiology, adaptation, what we have right, and where I think we’ve gone wrong.

These thoughts come from a long journey through the problem of evolution. I say “problem” not because I disbelieve in evolution, but because there is much about how we think about it that doesn’t make sense. I have worked through this issue in three books:

The Extended Organism. The Physiology of Animal-Built Structures (2000). Harvard University Press. The Extended Organism took a critical look at the phenomenon of adaptation.

The Tinkerer’s Accomplice. How Design Emerges from Life Itself (2007). Harvard University Press. The Tinkerer’s Accomplice explored the phenomenon of design-why do living things conform so often to principles of good design.

Purpose and Desire. What Makes something “Alive” and How Modern Darwinism has Failed to Explain It (2017). HarperOne. Purpose and Desire explores the incoherency that permeates modern Darwinism, and offers my proposal to bring coherency back to evolutionary thought, and to how we think about life. Hint: most biologists won’t like my answer. Purpose and Desire will be released on 12 September 2017.

You can also visit my Author’s Page on amazon.