One of Peter Saunders' principal research interests is explaining the properties of complex nonlinear systems, and he's long been a critic of the Modern Synthesis. But Saunders, Emeritus Professor of Mathematics at King's College London, thinks that at least some of the current angst in the neo-Darwinist camp in response to challenges regarding its theory of evolution simply has to do with confusion over the term "epigenetics."
A paper on epigenetics that Saunders and his wife, geneticist Mae-Wan Ho co-authored decades ago was cited earlier this year by Denis Noble as inspiring, in part, his JEB paper about replacing the Modern Synthesis. I reached Peter Saunders recently for comment about all of this at his home in London. In our interview that follows, Saunders -- to be fair -- reserved a bit of his criticism for developmental biologists.
Peter Saunders serves as co-director of ISIS, the British organization whose mission is "to reclaim science for the public good." His PhD is in theoretical astrophysics from the University of London, his BA in applied mathematics from the University of Toronto. He is the author of An Introduction to Catastrophe Theory; co-editor of the books Beyond neo-Darwinism (with Mae-Wan Ho) and of Theoretical Biology (with the late Brian Goodwin).
Suzan Mazur: Would you comment on the angst and denials of the neo-Darwinists regarding epigenetics?
Peter Saunders: The confusion is the word epigenetics. When we wrote that paper in 1979 and I still say so now [noting "a proper study of evolution consists in the working out of the dynamics of the epigenetic system and its response to environmental stimuli as well as the mechanisms whereby novel developmental responses are canalized."] -- we were using the word epigenetic in the sense that it had been used by Conrad Waddington from 30 years before that. And basically to him epigenetics was effectively a synonym for development. The concept of developmental biology.
The word is now used in an almost totally different sense, which has got to do with changes in the DNA that are not due to random mutations. They're due to environmental influences on genetic systems -- something the neo-Darwinists have also denied happening until recently. . . . That wasn't what we meant by epigenetics, and it still isn't what we mean when we're talking about rethinking evolution.
For instance, with a phenocopy [a phenotype that mimics the expression of a mutation] -- the best known example outside science is probably in butterflies. If you take an ordinary species of butterfly, it comes in different varieties, in different patterns. If you're a butterfly collector, you want to get every one of those varieties.
The idea is these different varieties are normally caused by chance mutations, and collectors try to collect them all. But sometimes it's hard to find one. So what they've learned is that if you put the pupae in the freezer for a while, you can get a butterfly that is genetically normal but which has the same markings as a mutant would have.
We would say that is a proof of the influence of what we call epigenetics. Because if it isn't the developmental system that does it, if it isn't a case of either an environmental perturbation or mutation simply kicking the developmental system into another pathway which already exists, how could you possibly explain the fact that the two -- that is to say a bit of chilling or a mutation -- have precisely the same effect on the organism? It makes no sense.
One other example is the babies born to mothers who took Thalidomide. You know the disadvantages they have, distortions of development. There is a rare mutation that does the same thing. That's what we meant when we talked about epigenetics. . . .
Suzan Mazur: Can you give a more concise definition of epigenetics?
Peter Saunders: I would define it as having to do with the developmental system.
Suzan Mazur: Isn't development now considered part of evolution since the 'evo-devo revolution' -- as Noam Chomsky describes it?
Peter Saunders: It is not. No.
The neo-Darwinists talk about the evolution of development but they do not talk about the process of development having anything to do with evolution. They can't, because it upsets the theory if they do.
This all goes back to the old days of the theory of the homunculus. There were two theories at the time. One was the homunculus, where everything was thought to be already in the egg before the start, the thinking was that everything is determined at the start -- "preformed."
Epigenetics was the opposite of preformation, rather than things being preformed, the idea was that things develop as you go along. Essentially, the genetic theory that underlies neo-Darwinism is a preformationist theory. Everything that matters is there at the start. That's why the neo-Darwinists talk about a blueprint.
Suzan Mazur: I've interviewed so many scientists about natural selection and they all describe it differently.
Peter Saunders: Which says something about its status as a theory. . . .
A lot of the Modern Synthesis is irrelevant now, or at least secondary to what's going on. If you look back at the origin of the Modern Synthesis -- before that you just had ordinary, classical Darwinism. And you actually had neo-Darwinism, which meant something different in those days than what it means now. And there was a terrible problem, because without genetics, without knowing anything at all about how the traits are transmitted, and without knowing what happens within the body when the thing is developing -- Darwinism is going nowhere.
I remember once chatting with Ernst Mayr, and he admitted to me: " Look up until about 1920 I was a Lamarckian."
I was a bit surprised by Mayr's statement. He continued to say that it was the only theory at the time that made any sense. . . . But what they did was change the direction to concentrate on genetics. . . . The Modern Synthesis came about when people realized that if you applied genetics in a more appropriate way to evolution you could explain a lot more. But by now the geneticists have told us almost everything important they have to say, and the real advances are going to come from other disciplines, above all developmental biology.
Suzan Mazur: So what happens to the Modern Synthesis?
Peter Saunders: What do I think will happen to the Modern Synthesis? You have to think of it not as a theory, which can be modified or superseded, but as a paradigm, in the sense of Kuhn's Structure of Scientific Revolutions. It's a body of shared knowledge, understanding and experience, generally with some theory at its core. One of Kuhn's points is that work within a paradigm is judged in terms of its contribution to the paradigm, not in some difficult to define sense of contribution to science.
Thus for example, I've often heard neo-Darwinists say how important Bill Hamilton was because of his theory of kin selection. Kin selection is very important within neo-Darwinism because they see it as a solution to what I have called the "problem of good" (by analogy with the "problem of evil" in Christian theology). If you believe that the only significant force in evolution is natural selection, this is a serious problem, possibly even a threat to the whole theory of evolution. So finding a solution was a major advance. To anyone outside the paradigm, it's an interesting idea but not all that important.
There won't be a crucial test, like the 1919 observations that supported General Relativity over Newtonian gravitation. There can't be, because neo-Darwinism isn't falsifiable, which is one of the ways we can tell it's a paradigm rather than a theory. But in all sorts of different ways, the paradigm is gradually losing its dominance.
I think it will be one of those cases that it dies because its supporters die. The thing that would make the biggest difference would be if developmental biologists suddenly decided they had something to contribute to evolution and started doing the work. . . .