Suzan Mazur interviews Massimo Piattelli-Palmarini | Scoop: Friday, 9 May 2008
Piattelli-Palmarini: Ostracism W/out Nat Selection
“[I]nsects had evolved at least ten elaborate forms of mouthpieces, uniquely adapted (one would say) to their feeding upon flowers, one hundred million years before there were any flowers on Earth.” — Massimo Piattelli-Palmarini
I met celebrated philosopher Jerry Fodor for coffee on Charles Darwin’s birthday earlier this year to discuss the book he’s co-writing on evolution without adaptation… Fodor didn’t care that Darwin’s evolution theory couldn’t account for the origin of body plans — what he wanted to argue was that
whatever the story turns out to be, it’s not going to be the selectionist story
and joked that he was in the Witness Protection Program because of his views. Fodor’s co-author, Massimo Piattelli-Palmarini, the distinguished professor of cognitive science at the University of Arizona — who’s handling the biology for the book — is intrigued by origin of form and recently agreed to pick up where Fodor left off…
[Get the scoop on Suzan Mazur and Massimo Piattelli-Palmarini here.]
Suzan Mazur: In the book you’re writing with philosopher Jerry Fodor on evolution without adaptation, do you share his view that we need a new theory of evolution and that the theory of natural selection is “wrong in a way that can’t be fixed”?
Massimo Piattelli-Palmarini: Yes, I do. Of course, there is natural selection all around us (just think of the flu virus, mutating and adapting every year, to our detriment) and inside us (just think of our antibodies and our synapses and the pancreas cells and the epithelial cells). The point is, however, that organisms can be modified and refined by natural selection, but that is NOT the way new species and new classes and new phyla originated.
For that, major changes in regulatory genes and in gene regulatory networks have to occur. All this is perfectly naturalistic and now well documented. Minor changes in the order of activation of master genes can create vast discontinuous morphogenetic changes...
More and more papers, from different quarters (laboratories and researchers still that remain for the most part isolated from one another), show that there are physical principles of optimization, and of optimal compromise, acting on biological forms. For instance, Christopher Cherniak and colleagues at the University of Maryland have computed literally millions of alternatives to the way the nervous system is organized, from the ganglia of the earthworm (the nematode) to the auditory cortex of macaques, and found that none of these can improve to what we have in reality. Nature has found an optimal solution for the density of connections that is better than the most advanced engineered chips we find on the market today.
A few years ago… West, Brown and Enquist discovered that the natural ramifications in all circulatory systems (the sap and lymph circulation in trees; the veins, arteries and capillaries in mammals) follow a maximal fractal law. Best transport with minimal distance. Something that evolution has “rediscovered” over and over. Other instances of optimization are found in other components of biological systems. In phyllotaxis (the geometry of leaves and of flower petals), we see reproduced the Fibonacci perfect spiral, our phalanges have lengths of 1, 2, 3, 5, 8 (the Fibonacci series), and so on.
Now, it just cannot be the result of natural selection that biological forms show the same forms we also witness in spiraling minerals and in spiral galaxies. And when we find a “solution” in living beings that turns out to be optimal with respect to many millions of conceivable (and computable, these days, with fast computers) alternatives, it cannot have been selected out of random trials. There have not been dozens of millions of generations of macaques trying out all sorts of cortical patterns of connections, such that only the best survived. That’s ridiculous.
Suzan Mazur: Why has American science been slow to accept a reduced role for natural selection in evolution? Is it the physics that people just can’t grasp?
Massimo Piattelli-Palmarini: It’s not just American science, but rather Western science, though indeed France has, in this respect, a different story, not quite a noble one… Anyway, even if we take the many, many biologists in many countries who have contributed to the new rich panorama we have today of non-selectionist biological mechanisms (including the masters of the Evo-Devo revolution), they are reluctant, in my opinion, to steer away from natural selection. They declare that the non-selectionist mechanisms they have discovered (and there are many, and very basic) essentially leave the neo-Darwinian paradigm only modified, not subverted.
I think that abandoning Darwinism (or explicitly relegating it where it belongs, in the refinement and tuning of existing forms) sounds anti-scientific. They fear that the tenants of intelligent design and the creationists (people I hate as much as they do) will rejoice and quote them as being on their side. They really fear that, so they are prudent, some in good faith, some for calculated fear of being cast out of the scientific community.
There are, however, also biologists who do not fear to declare, as Gregory C. Gibson (the William Neal Reynolds Distinguished Professor of Genetics, North Carolina State University) wrote in Science (2005), reviewing a book on robustness and evolvability:
[this book] contributes significantly to the emerging view that natural selection is just one, and maybe not even the most fundamental, source of biological order.
Robustness must involve non-additive genetic interactions, but quantitative geneticists have for the better part of a century generally accepted that it is only the additive component of genetic variation that responds to selection. Consequently, we are faced with the observation that biological systems are pervasively robust but find it hard to explain exactly how they evolve to be that way. (G. C. Gibson SYSTEMS BIOLOGY: The Origins of Stability. Science, 310 (5746), p. 237.)
Prudent, but explicit… There are other expressions of discontent with canonical neo-Darwinism, but, all in all, prudence prevails… when Sherman stresses that the sea urchin has, in-expressed, the genes for the eyes and for antibodies (genes that are well known and fully active in later species), how can we not agree with him that canonical neo-Darwinism cannot begin to explain such facts?… Self-organization is of course an important component, but not much has been discovered beyond generalities. The immense amount of intricate detail that geneticists and developmentalists have been discovering over the years dwarfs general metaphors like autoevolution and even self-organization. The challenge now is to integrate, not to substitute these metaphors for hard work over many years…
Suzan Mazur: How long do you estimate it will take for theory of form to be understood and gain credence within the scientific mainstream.
Massimo Piattelli-Palmarini: Well some 20 years for the elite of the scientific community. Maybe 50 before it becomes high-school textbook material…
Suzan Mazur: When do you expect your book will be published?
Massimo Piattelli-Palmarini: Sometime in late 2009. But mind you, it contains some of these ideas, but also other important ideas I did not even mention here. Notably that the strict analogy between Behaviorism and neo-Darwinism is quite fatal to the second, though few seem to have noticed. How can the first be agreed to be defunct but not the second? Also, the ineliminable intensional (mentalistic in some unrecognized way) character of notions such as selected for and ecological niche. But for these, you have to wait to read it.
[Meanwhile you can read Fodor on Adaptationism by Yours Truly.]
Finally, it will be called What Darwin Got Wrong. Not final yet, but probable.
