The Intelligent Design Creationists are promoting Michael Denton's new book Evolution: Still a Theory in Crisis. The new buzzword is "structuralism" and it's guaranteed to impress the creationist crowd because nobody understands what it means but it sounds very "sciency" and philosophical. Also, it's an attack on "Darwinism" and anything that refutes evolution has to be good.

You can watch Michael Denton explain structuralism ... it only takes a few minutes of your time.

As Denton says, the basic idea is that the form (structure) of modern organisms is a property of the laws of physics and chemistry and not something that evolution discovered. He would argue that if you replay the tape of life you will always get species that look pretty much like the species we see today because the basic forms (Baupläne) are the inevitable consequences of the underlying physics.

To someone like Denton, this is confirmation of his view that God created the universe and endowed it with all the properties (laws of physics and chemistry) that would inevitably produce humans.

This is an old idea. Denton talks about Richard Owen (1804-1892) but there are many other famous structuralists from the 19th and 20th centuries. It's not a kooky creationist invention.

We should be learn about the modern versions of structuralism since the arguments take into account our current understanding of biology and evolution. One of the modern proponents was Brian Goodwin (1931 - 2009) a biologist at the Open University (UK) who was associated with the Santa Fe Institute in New Mexico (USA).

Goodwin wrote How the Leopard Changed Its Spots where he outlined his structuralist views. I read this book when it first came out in 1994 and I couldn't figure out what he was talking about back then. I have a better understanding now.

Here's an explanation from Goodwin himself published on John Brockman's Edge website: Biology is just a dance.

To introduce the problem: I like to compare morphogenesis with hydrodynamics. Suppose you have a fluid, and you want to understand why it takes certain shapes and forms: wind passes over it and it goes into waves, or you get whirlpools at the bottom of waterfalls. Why do liquids take these forms? What you need is a physical theory of fluids, which are a state of organization of matter. It's the same type of problem with organisms. Organisms are states of organization of matter. There are certain principles of spatial order in organisms, in cells, in the way cells interact with one another, and these can be written down as rules or equations, and then you can solve the equations on a computer and find out what shapes emerge, exactly the same way you can with liquids.

The hypothesis here is that life is a particular state of organization, a physical and chemical system. The problem is to find out what the rules are that apply to this state of organization of living systems.

So I see myself more as a physicist than an engineer, involved in a new synthesis of physics and biology. It's been attempted before, most notably by the Scottish zoologist D'Arcy Thompson, in his book On Growth and Form, in 1917 — an amazing achievement. He single-handedly defined the problem of biological form in mathematical terms. It's changed now, because we have new mathematical tools and a lot of new knowledge about organisms.

I want to emphasize that most structuralists do not connect their ideas to gods or creationism. Structuralism is anti-evolution but only in the sense that it requires something ("form") that has to be added to evolutionary theory ("functionalism") in order to explain the history of life.

The Edge published comments on the Goodwin article. People like Richard Dawkins, Stephen Jay Gould, Lynn Margulis, Dan Dennett, Steve Jones, and Murray Gell-mann all express their skepticism.

I particularly like the comment from Steve Jones ...

I've read some of Brian Goodwin's stuff, and I find it extremely hard to follow. That could be because I'm stupid. But I did embryology, I did development, I read molecular biology; that isn't so difficult to follow. Goodwin makes it hard. It's not an approach I like. I think he's a mystic. Anybody who goes to Santa Fe — there's something in the air there that's catching. Complexity is catching, that's the trouble.

I've been to Santa Fe and I spent a month at nearby Los Alamos. It's not the air that turns you into a fan of complexity and mysticism, it's the people at the Santa Fe Institute.

Denton has a paper on structuralism published in Bio-complexity a few years ago (Denton, 2013). The abstract does a good job of explaining the structuralist position.

Here I first review the structuralist or typological world view of pre-1859 biology, and the concept that the basic forms of the natural world--the Types--are immanent in nature, and determined by a set of special natural biological laws, the so called ‘laws of form’. I show that this conception was not based, as Darwinists often claim, on a priori philosophical belief in Platonic concepts, but rather upon the empirical finding that a vast amount of biological complexity, including the deep homologies which define the taxa of the natural system, appears to be of an abstract, non-adaptive nature that is sometimes of a strikingly numerical and geometric character. In addition, these Types exhibit an extraordinary robustness and stability, having in many instances remained invariant in diverse lineages for hundreds of millions of years. Second, I show that neither Darwinism nor any subsequent functionalist theory has ever provided a convincing adaptive or functionalist explanation for the Types or deep homologies. Third, I discuss how recent advances have provided new support for the structuralist notion that the basic forms of life are immanent in nature. These include the discovery of the cosmic fine-tuning of the laws of nature for life as it exists on earth, and advances in areas of molecular and cellular biology, where it is apparent that a considerable amount of biological complexity is clearly determined by the self-organizing properties of particular categories of matter, rather than being specified in detail in a genetic blueprint as functionalism demands.

One of the problems with structuralist explanations is that they are very animal-centric. They deal almost exclusively with examples from that tiny little circle (right) on the tree of life.

It's easy to think of deterministic forms when your view is limited to vertebrates and other animals but it's much harder to defend structuralism when you're comparing bumblebees and mushrooms.

There are plenty of good critiques of structuralism in the scientific literature. One of the best is by Paul Griffiths, an Australian philosopher of science and colleague of John Wilkins (Griffiths, 1994). Structuralism is a challenge to classification and definitions of species. I'm hoping that John will help us understand structuralism.

Here's what Paul Griffiths says,

The generic forms divide the overall space of biological possibility into discrete regions available to each particular type of organism. The process structuralists view this structuring of the space of biological possibility as part of the fundamental physical structure of nature. But the phenomena of phylogenetic inertia and developmental constraint do not support this interpretation. These phenomena show that the evolutionary pathways available to an organism are a function of the developmental structure of the organism. However, nothing in the phenomena suggests the sort of manageable periodic table of organismic forms that would be necessary to make the structural explanations of form envisaged by Goodwin (1994) genuinely explanatory. The generic forms that exist in nature may be a tiny subset of the possible generic forms that could have been created by the historical design of alternative developmental systems. In that case, an explanation of the organism's form in terms of which developmental system it possesses would in no way displace the Darwinian explanation of form in terms of descent with modification. The developmental system could have been any one of a number of ways depending on the particulars of evolutionary history.

There's nothing in science that supports the views of the structuralists. We have perfectly good explanations for why bumblebees are different than mushrooms and why all vertebrates have vertebrae and not exoskeletons. There's no evidence to support the idea that if you replay the tape of life it will come out looking anything like what we see today.

You can be confident that when you visit another planet you will not find vertebrates.¹ Denton is wrong.

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1. Or God.

Denton, M.J. (2013) The Types: A Persistent Structuralist Challenge to Darwinian Pan_Selectionism. Bio-Complexity 3: 1- 17 [doi: 10.5048/BIO-C.2013.3]

Griffiths, P.E. (1996) Darwinism, process structuralism, and natural kinds. Philosophy of Science, S1-S9. [PDF]