Michael Denton has a new book, “Evolution: still a theory in crisis“. So I picked up a copy, and will review it in this post. I actually purchased the Kindle version of the book.
Structuralism vs functionalism
Denton outlines the main gist of his argument in chapter 1, where he explains that he is a structuralist rather than a functionalist. He expands on that in later chapters.
Denton seems to be using “functionalism” to describe what I would call “pan-selectionism” or “pan-adaptationism”. So he would see Dawkins, and probably Jerry Coyne, as functionalists. Denton himself prefers structuralism, which is an emphasis on the forms or body plans (he uses the term “bauplan”) of organisms (or groups or organisms).
I’m inclined to say “a pox on both of their houses”. I am not a pan-selectionist. I usually say that I am not a Darwinist, for I see Darwinism as an over-emphasis on natural selection. To me, Denton’s preference for structuralism seems strange. Surely the structural features are their because of their functional role.
In section 1.1, Denton writes:
It is hard to imagine two scientific frameworks as diametrically opposed as structuralism and functionalism. Whereas functionalism suggests that function is prior and determines structure, structuralism suggests that structure is prior and constrains function.
To me, this just looks strange. Why need it be an either/or? I tend to look think of a population as acting in an apparently pragmatic way. It takes whatever structure it can come up with, provided that this serves the survival needs of the population. I expect that the structures used will be vastly under determined by the functional requirements for survival. It is the extent of that under-determination that seems to bother Denton.
What crisis?
In this book, as in a previous book, Denton suggests that the theory of evolution is in crisis. But he never clearly identifies what that crisis is. Having read the book, I am unable to see any crisis.
In section 1.4, Denton writes:
In preparing the final draft of this book, I came across a revealing quotation that illustrates the profound bias in modern biological thought against Owen and nineteenth-century typology. In a paper published in 2009, leading evolutionary biologist Massimo Pigliucci claimed that starting with Darwin evolutionary biology “moved from natural theology to empirical science… Rather suddenly, the concept of evolution moved firmly away from being a quasi-mystical notion, and biology left Paley’s (1802) natural theology forever behind to enter the realm of respectable science, just like physics had done two centuries before.”
But how can a framework like Owens, which posits natural law as the explanation for the Types and the evolution of life, be unscientific? And how can the Darwinian story, which is an historical narrative describing a series of contingent events, be “just like physics”?
It seems that Denton is looking at the theory as “an historical narrative”. To me, this is strange. I see the theory of evolution as an account of ongoing processes of change. And I see the role of examing fossils as one of checking whether the processes were about the same in earlier eras that they are now. I don’t see the theory as aimed at being an historical narrative.
It’s pretty much the nature of history, as a field of study, that it has to make do with a sparse collection of facts, and attempt to interpolate between them. This seems to be a particular concern of Denton. He has several chapters where he looks at what he sees as gaps in the history record. Chapter 7 is on cells and proteins, chapter 8 on flowering plants, chapter 9 is on limbs, feathers, etc, and chapter 10 is on human language. Denton presumably sees these gaps as the crisis. I don’t see the gaps as nearly as large as Denton thinks they are.
For example, consider human language. Denton sees a huge gap that needs to be explained to cover “universal grammar” and “deep structure” of language. He calls for a saltational explanation (an explanation involving leaps).
I’ll agree with Denton that there is a leap involved in universal grammar and in deep structure. I see that leap as having occurred around 1956, when Chomsky published his account of syntactic structures. Chomsky is a structuralist about language. I see Chomsky’s structural account as a poor fit for describing human language. And I see “universal grammar” and “deep structure” as fudge factors that Chomsky had to introduce in order to explain away how poorly his account of language fits. But I guess it is not surprising that Denton, as a structuralist about biology, would side with a structuralist account of language.
Readability
It should be obvious that I disagree with Denton’s thesis. His book is, however, quite readable. Denton presents his case well, even though I did not find it persuasive.
And I think I did learn something. The book suggested to me that the structuralist approach, and seeing the theory as an account of historical events rather than as an account of ongoing processes, might be a significant part of what drives creationist criticism of evolution.
The Heretical Philosopher 