Evolution: Still a Theory in Crisis
By Michael Denton, Discovery Institute Press, 2016
(358 pages with index, Kindle edition available)
A review by Will Jones
Michael Denton is a biochemist who has some questions for Darwinian evolution. Many of those who work in the field of evolutionary developmental biology, he notes, have started to question whether Darwin’s theory really does hold all the answers for the traits they are studying. There is no doubt, of course, about natural selection, or common descent over millions of years, or the progressive emergence of higher and more complex forms of life. Those are beyond question. But Darwin’s explanation for how the novel characteristics of organisms emerge – gradually, through numerous slight successive beneficial adaptations – is very specific, and may not provide the best explanation for many of the most important characteristics of biological life.
In particular there are the homologs, says Denton – the traits shared by all the members of a particular biological group which define them as belonging to that group, the “taxa-defining novelties” which underpin the schema of the great tree of life. Examples include hair, feathers, the pentadactyl limb, the diaphragm, and many more.
There are three problems with a classical Darwinian explanation for these traits, says Denton, a British-Australian biochemist and author of the influential 1985 book Evolution: A Theory in Crisis, to which the present book is a follow-up. The first is the lack of transitional forms present in the fossil record to show the development of the traits from more primitive forms – at their first appearance they are already the finished product. This might just be attributable to awful luck with the fossil record, but then there is the second problem: for many of them, such as the pentadactyl limb, which is common to all tetrapods, the precise structure of it (three bones and five digits) serves no specific adaptive purpose, so that it is not even clear why the finished product would be selected, let alone the elusive steps leading up to it. Furthermore, and this is the third problem, these traits have been conserved inviolate, some of them for over 400 million years. Indeed, it is because they have been conserved that they define the taxa and other groups, demarcating remarkably clear boundaries between unchanging subgroups. Some have even appeared multiple times independently over evolutionary history. Where then did they come from, these non-adaptive traits with no natural history – no lead-up to them, and no move away from them, these fixed points in the emerging tableau of life? Darwin’s mechanism, effective though it clearly is for bringing organisms into greater affinity with their environment, offers no hope for an answer here.
Denton is a proponent of Intelligent Design, but he has no interest in exploring ideas of special creation or divine intervention, not least because he describes himself as an agnostic. These are natural phenomena he is studying and he is only interested in a natural solution. He finds his answer in the great Victorian biologist Richard Owen, the founder of London’s Natural History Museum, whose rival structuralist account of biology to Darwin’s functionalist account Denton believes holds out hope for an alternative and more convincing explanation for the remarkable patterns and homologies of nature.
The key to this approach is the concept of natural law coupled with the idea of the fine-tuned cosmos – fine-tuned in both the universal constants and in the operation of the laws of nature. This fine-tuning means that life, and indeed life as we know it, is not just made possible by the way the universe is structured, but all but inevitable and necessary. The homological traits, Denton contends, reflect the operation of the laws of nature on biological matter in a way precisely analogous to the way the ordered array of atoms and crystals reflects the operation of the laws of nature on subatomic and atomic particles. The homologies appear, and they stick around, because of forces internal to matter which predispose them to form and to hold together over vast periods of time. These forces limit in myriad ways the permissible patterns which matter can adopt, and so force its hand towards those which serve to facilitate and constitute life.
That’s why organs know their morphology – their shape isn’t in their genes, as geneticists are now increasingly realising, but overwhelmingly epigenetic. It is also why proteins know how to fold down to their lowest energy state without tying themselves in knots. And it is why so much of biological matter exhibits such a remarkable degree of self-organisation and self-assembly, without any need for external input or evidence of genetic coding. It is, then, not just evolutionary development that would be explained by this structuralist thesis: it would unify ordinary biology with evolutionary biology under a single natural law based framework which would place biological science on the same solid ontological footing as the other natural sciences. This, for Denton, is one of its great attractions.
Where would this leave Darwinism? It wouldn’t invalidate it of course – that is impossible. Darwinian natural selection obviously occurs, for the environmental constraints of fitness will always result in adaptations arising from successive instances of natural variation. What it would do, though, is relegate it to a supporting role – an “adaptive mask” as Denton calls it, citing Owen, over the more fundamental “primal patterns” which undergird the tree of life and hold it together over the aeons.
Denton is helpfully candid in the book about the possible theological implications of the thesis, but is keen to play down their significance and focus on finding the best account of the empirical data – a reflection, perhaps, of his own agnosticism. He isn’t in this to push a particular doctrinal agenda but to follow the facts.
I found this book an accessible explanation of an ambitious, yet undeniably attractive thesis – though it could, I feel, have been made more accessible through being more careful with its use of technical terminology, using warnings and distinguishing technical and non-technical sections, as is common in popular science books these days. Some sections, particularly early on, felt a little close to the polemical, and the whole book would have benefited from some rationalisation to avoid repeating itself too much, and to ensure that key points were made in their clearest and most arresting form. Personally, I would have liked to have seen something on the possible meaning of the thesis for the existence and character of extra-terrestrial life, which seemed to me an obvious big implication. But these are just quibbles.
Overall, this book represents a bold attempt to present the alternative framework to Darwinian evolution that seems so lacking in current biological debate and might well explain the data better. Even if you find yourself disagreeing with Denton’s arguments and conclusions, you will benefit from having read and considered this book, for evolutionary biology is currently a discipline in flux, and this sets out the problems well and takes a decent shot at a solution.
Will Jones is a mathematics graduate with a PhD in philosophy who is involved with two social theology projects in the UK.
Evolution: Still a Theory in Crisis
By Michael Denton, Discovery Institute Press, 2016
First published in Essentials, Autumn 2019
It is 3 am. Unable to sleep, I arose to continue reading Michael Denton’s Evolution: Still a Theory in Crisis (2016). To my surprise I turned a page and found it was the last. Some authors have a lot of footnotes!
Sadly, I have never studied biology, so am unable to assess much of the evidence and argumentation, except in a superficial common sense way. I wish someone better equipped than I would help us here. Having said that, the book reinforces my own growing conviction that the Darwinian model of evolution is too simple by far, and fails to bring us to a right understanding of what one of my childhood books on evolution called ‘the miracle of life’.
Denton does not declare himself as a believer or even a theist; Wikipedia calls him an agnostic. His faith position generally remains hidden. He approaches Darwinism (and Neo-Darwinism) as a molecular biologist and an evolutionist, assessing its evidential basis, finding it lacking, and reaching out for an alternative mechanism for the bewildering variety of life forms.
Variation and adaptation he fully accepts, along with the notion of natural selection. However, he observes that there are many big structures imbedded in nature—he calls them types or homologues—which are the foundations on which this variation operates, and which cannot themselves be accounted for as gradual modifications of an original simple life-form. Examples he explores in detail are the pentadactyl limb (one bone plus two bones plus five digits) ‘conserved in all tetrapods for 400 million years’; also the feather, hair, the insect body plan, the flower, the amniotic membrane, the insect wing (‘every detail of the developmental program is an enigma in terms of adaptive gradualism’; p. 95), the enucleate red blood cell of all mammals (this is Denton’s speciality; he did his Ph. D. on the red blood cell), and the cell itself. The ground-plan of the cell, ‘the basic unit of all life on earth’ is unchanged in 4000 million years (p. 120). He has many more examples; Denton speaks of ‘a universe of non-adaptive forms’ (p. 76). At one point he mentions a million ‘taxon-defining homologues’ (p. 45).
These homologues have no apparent antecedent structure in the fossil record, nor any theoretical pathway by which they might have arisen by small adaptive steps. Writing on the cell, and the developments in biology in the thirty years since he wrote Evolution: A Theory in Crisis (1985) Denton says, ‘Despite a vast increase in knowledge of supra-molecular chemistry and of cell and molecular biology; the unexpected discovery of ribozymes; and an enormous effort, both experimental and hypothetical, devoted to providing a gradualistic functionalist account of the origins of life in terms of a long series of less complex functional replicating systems … leading from chemistry to the cell, no one has provided even the vaguest outlines of a feasible scenario, let alone a convincing one.’ (p. 121) This should be read along with his mind-blowing description of the cell in the 1985 book: pp. 328-330.
In 1989 I read Denton’s first book. It left me in wonder at the complexity of life and life forms—especially the cell—and a growing scepticism regarding the evolutionary model I had grown up with. Mistakenly, I thought Denton was challenging the whole macro-evolutionary paradigm. Reading his latest work makes it clear that he is not. His challenge is to the Darwinian and Neo-Darwinian paradigm. His quest is for an alternative. Recently I re-read, Evolution, A Theory in Crisis. I see now why it impacted on me so powerfully in 1989. As a student in the 60s I accepted Darwin’s notion that the whole of life evolved as a result of small changes, natural selection, and the survival of the fittest. I accommodated it easily to my new faith, reasoning that God’s providence could have guided the whole process to his intended conclusion. I could not see how a structure as complicated as the eye could have arisen without some guidance; age has added to that conviction. However, doubts over Darwin arose when I was still a student. In 1959 Everyman’s Library published a centenary edition of The Origin of Species. The introduction was by a leading Canadian biologist. He summarized the theory and then inquired whether the evidence of one hundred years supported it. He found it did not, and lamented the amount of biological research which was wasted on building imaginary evolutionary trees. From then until 1989 I was an evolution ‘agnostic’. A Theory in Crisis (1985) reviews the evidence for grand evolution and concludes that it not only does not support Darwin’s idea, but conflicts with it at many levels. Denton’s argument is so strong, especially in his own area of molecular biology, that, with my Christian spectacles, I read it as an outright refutation of grand evolution—which it is not.
This becomes clear in his later book, Evolution: Still a Theory in Crisis (2016). Denton thinks the world is old, and that the various forms of life evolved. The question is how. He finds Darwin’s solution unworkable and seeks an alternative in what he calls ‘structuralism’. In this he is going back to some of the great biologists of the nineteenth century, in particular Richard Owen, founder of the Museum of Natural History in London. There are deeply imbedded biological structures, which appear to be part of the nature of things in the physical world. In the inorganic world crystals form under certain conditions, constrained by the forces of nature; so, structures ‘emerge’ in the biological world as a result of physical constraints. Denton illustrates this from an amount of recent research. It was an eye-opener to me that the 20th century notion that everything is determined by what is encoded in our DNA, is being abandoned in the 21st. The shape of the human body, for example, does not seem to be determined genetically, nor does the language ability of humans (which Denton identifies as another ‘homologue’). DNA is not all there is to it! Some other explanation is required, and he finds this in ‘epigenetic’ forces (analogous to crystallization) which emerge in extraordinarily complex protein systems. Admitting that this might be a factor in biological development, I baulk at it as an explanation of, for instance, the pentadactyl limb-structure. It clearly does not work as an explanation of the cell itself, where Denton has himself ruled out intermediate forms.
In his last chapter Denton explores the implications of his work for teleology (he avoids bringing God into the discussion) where he favours the view that the basic forms of life are ‘no less built into nature than the properties of water’ (p. 278). ‘There is the deep hint—arising from the cosmological discovery of the fitness of nature for life—that the life forms on earth may be after all, an integral part of the cosmic order.’ (p. 278f. Denton’s italics.) For those who know God, this has evident interest. This latest book should be read and discussed, though the first is foundational, and is an easier read. Evangelicals who for a long time now have accorded Darwinism almost the status of a doctrine should take note of this authoritative scientific refutation of Darwin’s grand scheme and review their thinking.