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


Piattelli-Palmarini: Ostracism W/out Natural Selection

by Suzan Mazur


Massimo Piattelli-Palmarini

“[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. Snow fell over Manhattan that day, an uncanny reminder that Darwin had no theory for how snowflakes form or for humans either. But 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.

Massimo Piattelli-Palmarini has a PhD in physics from the University of Rome. Through the years he’s been a visiting professor at Harvard, MIT, the University of Bologna and the College de France in Paris. He spent eight years as principal research scientist at MIT’s Center for Cognitive Science. It was at MIT that Piattelli-Palmarini first met Jerry Fodor and linguist and beloved activist Noam Chomsky, eventually collaborating with both on books.

He’s also served as Director, Florence Center for the History and Philosophy of Science and Director, Royaumont Center for a Science of Man, Paris.

Piattelli-Palmarini is the author of a half dozen or so books, notably Inevitable Illusions and Ritrattino di Kant ad Uso di Mio Figlio (Portrait Kant to use My Child), for which he received Italy’s Premio Tevere for non-fiction.

He was also awarded the Accademia d’Abruzzo, Premio Il Rosore d’Oro for his work as a public science intellectual. And he’s a regular science contributor to the Italian newspaper Il Corriere della Sera.

In describing Charles Darwin’s theory of natural selection, Piattelli-Palmarini tells the story about a boy asking his father why rocks fall to the ground and his father answering that when the Earth was young some rocks floated away from the planet, some suspended in air and eventually floated away, and some fell to the ground. The remaining ones on the ground fell to the ground.

Our interview follows.

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”?


Jerry Fodor

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. Very similar (in the jargon orthologous) genes in insects and in vertebrates produce an inversion in the development of the nervous system.

In essence, in insects the system is ventral, in vertebrates it’s dorsal. Two opposite gradients of morphogenetic factors (one the mirror image of the other) produce this difference. Huge difference to the eye, but minor in its origin early in the development of the embryo.

There will be one day, decades from now, I am persuaded, hanging on the walls of the schools, some equivalent of the Periodic System (Mendeleev Table) showing how these genetic regulatory switches combine to give the different forms of life (this is just a metaphor, of course, but I bet it will become a detailed plan one day).

Suzan Mazur: Jerry Fodor told me you were handling the biology for the book, but you also have a PhD in physics in addition to being a cognitive scientist. Do you have a hypothesis on origin of form? And would you tell me a little about what you’re teaching your class there at the University of Arizona on form?

Massimo Piattelli-Palmarini: Yes, I have a doctorate in physics, quite rusty now. And yes, I think that there are fundamental physical and chemical principles operating inside all living systems and partially responsible for the forms of living organisms. Only partially, of course, but at a very fundamental level.

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, in Santa Fe (yes, the Institute so dear to you and to
Kauffman) 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.

Some consider Darwinism to be quintessentially “Britannique” and they had Bergson suggesting a different approach to evolution, then the mathematician Rene’ Thom and his school, stressing the role of topological deep invariants. They may have come to anti-Darwinian conclusions for rather idiosyncratic reasons.

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.

And the distinguished evolutionary biologist Massimo Pigliucci, in an excellent book co-authored with the philosopher Jonathan Kaplan, writes:

“It is unwarranted to think that adaptation, diversification and evolution more generally are closely related phenomena that take place via the same mechanisms in the same populations […] Adaptation can, and verifiably does, take place without speciation, as does nonadaptive evolution more generally”.
Massimo Pigliucci & Jonathan Kaplan (2006), Making Sense of Evolution: The Conceptual Foundations of Evolutionary Biology. Chicago: The University of Chicago Press. (Chapter 9, Box 9.2).

There are other expressions of discontent with canonical neo-Darwinism, but, all in all, prudence prevails.

Suzan Mazur: It’s interesting that there’s been a meeting of minds among biologists, philosophers and linguists about language in evolution. Didn’t you, MIT linguist Noam Chomsky and the late paleontologist Steve Gould at one point all share similar thinking that language was due to laws of structure and growth and not natural selection?

Massimo Piattelli-Palmarini: Yes, that’s exact. Gould’s untimely death did not allow him to develop fully this side of the issue, but cogent reasons for not trying to explain cognition and language along neo-Darwinian lines have been iterated by his main co-author, Richard Lewontin.

Steve and I taught twice, several years ago, at Harvard, a course together and we had mighty opponents attending it (notably Steve Pinker and Daniel Dennett) giving life to quite animated discussions.

Chomsky gave a guest lecture in that course, with the Nobelist David Hubel also attending (you see how lucky I have been, a dwarf among such giants) and the debate was intense, though friendly. In essence, at the time Chomsky cogently argued (and I reinforced this in some publications of mine) that the very structure of language has peculiarities that cannot have been shaped by (naturally selected as) sub-products of communication, nor thinking. They appeared then (around 1985) too idiosyncratic to be the result of a functional selection.

Today (ever since, approximately 1995) the message is basically the same, but with a change of emphasis. There appear to be in language, at a suitably high level of abstraction, properties of elegance and maximization that explain those peculiarities as applications. What once were considered to be explanations (the principles of a restricted set of syntactic modules) now are considered themselves data to be explained. This is called the Minimalist Program, something that has fascinated many linguists, who have engaged with Chomsky (though sometimes there are points of technical dissent) in this program very thoroughly, with what I consider to be very interesting new results.

But it has distanced, in some case even repelled, other linguists. Time will tell whether this research program is right or wrong. I think it’s right, though still very preliminary. At any rate, there is no place in this program for any adaptationist, gradualist, neo-Darwinian explanation This much has not changed.

Suzan Mazur: Do you also think that structure, i.e., form is due to a language as Stuart Newman and Ramray Bhat hypothesize in their recent Physical Biology paper Dynamical patterning modules: physico-genetic determinants of morphological development and evolution?

Newman & Bhat describe the role of a pattern language — DPMs (dynamical patterning modules) — in the self-organizing formation of all 35 animal phyla around the time of the Cambrian explosion a half billion years ago.

Would you comment briefly on the Newman & Bhat paper?

Massimo Piattelli-Palmarini: I find this kind of morpho-dynamic approach immensely productive. The term “language” could be left out, but the basic ideas are right and very interesting.

Similar ideas have been expressed, among others, by Eric H. Davidson and collaborators (at Caltech) arguably the leading expert today of genetic regulatory networks.

Modularity and entrenchment in development are mature fields and discoveries towards discontinuous patterned changes in developmental constraints are being published every month (see Psujek, S. and R. D. Beer (2008). “Developmental bias in evolution: evolutionary accessibility of phenotypes in a model evo-devo system.” Evolution & Development 10(3): 375-390. Just published).

A biochemist at Boston University, Michael Sherman, has proposed the idea of a “universal genome”, so akin to Chomsky’s idea of a universal grammar (then unbeknownst to Sherman) that Michael is now reading some minimalist linguistics and tells me he finds that field extremely interesting and congenial.

Symmetrically, Chomsky told me about Sherman’s approach that he thinks decades from now will become “mainstream biology” (his words).

As I said earlier, my way of depicting what will happen decades from now, is a sort of universal chart of morphogenetic pathways that will be displayed like today’s Mendeleev’s table is. I think too that this will be the mainstream biology of the future.

Look, 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?

Suzan Mazur: Who are some other evolutionary thinkers with views along this line you find interesting?

Massimo Piattelli-Palmarini: Well, of course, Stuart Kauffman, whom you have recently interviewed, a pioneer in the search for physical bases of biological morphogenesis (his name and his earlier work were pointed out to me by Steve Gould around 1985). Eric Davidson, mentioned above, Gerd Mueller and Stuart Newman, just mentioned, Gunter P. Wagner and the whole idea of entrenchment and modularity, Massimo Pigliucci, and of course the main authors in Evo-Devo (for instance Sean Carroll, Mary-Jane West-Eberhard and Marc W. Kirschner), though they are sometimes over-prudent in keeping within a neo-Darwinian frame.

Not many of them, with the exception of Kauffman, point towards physical invariants in morphogenesis, but their important data offer the basis that any such approach will have to take into consideration.

Suzan Mazur: Do you consider self-organization or autoevolution, as cytogeneticist Antonio Lima-de-Faria calls it, a kind of self-determination? And if so, why would people resist that idea regarding evolution?

Massimo Piattelli-Palmarini: Well, Lima-de-Faria wants to do without selection altogether, an extreme view.

The difficult issue, as Kauffman had emphasized years ago, is to integrate physical principles, genetics, development and different kinds of selection, acting in different ways at different levels.

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: Do you think the Konrad Lorenz Institute’s July symposium about an “Extended Evolutionary Synthesis” – where theory of form and non-centrality of the gene will be an important part of the discussion – will help to steer the scientific community and the public toward a better understanding of how form arose without selection?

[Stuart Newman will present his paper, co-authored by Ramray Bhat, at the KLI symposium in Altenberg on how all 35 animal phyla self-organized a half billion years ago at the time of the Cambrian explosion, with selection coming into play as a “stabilizer” after the highly plastic multicellular organisms formed.]

Massimo Piattelli-Palmarini: We said [evolution] without adaptation, not without selection.

There is selection, there has to be selection, though not the macroscopic, uni-level selection of classical neo-Darwinism. How genes interact with the physical factors we saw earlier here still remains to be determined How evolution and selections (plural here) “ride” so to speak the narrow channels of what is physically possible is still a mystery.

It does not help to depict the genes as inert stuff, dead material. Of course the whole cell is needed for them to be activated, expressed and so forth. But genes can be transplanted, cut, spliced, duplicated etc.

It’s silly to preach anti-geneticism. The real new synthesis will have to be between all these components, none excluding the others.

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: Developmental biologist Stuart Kauffman, one of the pioneers of self-organization, rejects reductionism in his new book, Reinventing the Sacred, saying that a couple in love walking along the Seine are not just particles in motion. What are your thoughts about this?

Massimo Piattelli-Palmarini: I like him and his work, but this is not a sensible remark. Who ever claimed they are? Perfusing his quest for the basic laws of morphogenesis with this kind of holistic humanism does not help, sorry.

More interesting is to ask whether a chromosome is a giant molecule or a society of interacting modules. We do not know zilch about the meaning of the number of chromosomes in the different species.

That number cannot be altered (chromosomal aberrations in humans, even minor ones, produce well known syndromes, some lethal), but nobody has an explanation on what it means for us to have 46, for the platypus to have 52 (of which 10 are sexual), and for the chimp to have 48.

One day, I bet, these data will be part of the mural table I anticipate, but as of now no one has the faintest idea.

Reductionism is bad when it’s bad, when it destroys what is to be explained. But it’s mighty good when it’s good, when the assembly of the parts does explain the property of the whole.

I resist humanistic anti-reductionism. Without intelligent reductionism we would not have the science we know and like. Mendeleev’s table is also a kind of reductionism, a welcome one.

Suzan Mazur: Of the theories on origin of form out there at the moment that you’ve reviewed – which do you find most plausible?

Massimo Piattelli-Palmarini: Factorial discrete changes in the regulation of master genes, and topological invariants in living forms. A bit of what D’Arcy Thompson and others had in mind, but with close integration of genetic regulatory networks. No simple overarching solution will work. Many factors will have to be integrated.

Suzan Mazur: Have you seen any convincing new illustrations and evolutionary models?

Massimo Piattelli-Palmarini: The idea of a universal genome, a’ la Sherman, is the most interesting I have seen recently. Not a single key, but an important key.

Suzan Mazur: Would you comment on Stuart Pivar’s animations of body parts?

Massimo Piattelli-Palmarini: Very interesting, though his idea that the torus is the mother of all forms is not persuasive. There must be a dozen of such mothers, not just one.

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.

Finally, it will be called What Darwin Got Wrong. Not final yet, but probable.

*************

Suzan Mazur says her interest in evolution began with a Cessna single engine flight into Olduvai Gorge, across a closed Kenyan-Tanzanian border, to interview the late paleoanthropologist Mary Leakey. Their meeting followed discovery of the 3.5 million year old hominid footprints by Leakey and her team at Laetoli http://en.wikipedia.org/wiki/Laetoli. Mazur says Leakey was the only reason the Tanzanian authorities agreed to give landing clearance. Her reports have since appeared in the Financial Times, The Economist, Forbes, Newsday, Philadelphia Inquirer, Archaeology, Connoisseur, Omni and others, as well as on PBS, CBC and MBC. She has been a guest on McLaughlin, Charlie Rose and various Fox Television News programs. Email: sznmzr@aol.com

Content Sourced from scoop.co.nz
Original url

No comments yet.

Write a comment: