Monday, January 17, 2011

The Woodstock of Evolution? The Extended Evolutionary Synthesis

On March 4, 2008, journalist Suzan Mazur published an online article entitled "Altenberg! The Woodstock of Evolution?, which began with this paragraph:

It's not Yasgur's Farm, but what happens at the Konrad Lorenz Institute in Altenberg, Austria this July promises to be far more transforming for the world than Woodstock. What it amounts to is a gathering of 16 biologists and philosophers of rock star stature--let's call them "the Altenberg 16"--who recognize that the theory of evolution which most practicing biologists accept and which is taught in classrooms today, is inadequate in explaining our existence. It's pre the discovery of DNA, lacks a theory for body form and does not accommodate "other" new phenomena. So the theory Charles Darwin gave us, which was dusted off and repackaged 70 years ago, seems about to be reborn as the "Extended Evolutionary Synthesis."

Proponents of intelligent-design creationism such as Paul Nelson and Casey Luskin used Mazur's reports about the "Altenberg 16" as evidence that Darwin's theory of evolution was a "theory in crisis," because it was being attacked by leading scientists. Defenders of evolution against creationism--like Nick Matzke--responded by arguing that the scientists at the Altenberg conference were not denying but deepening the foundations of evolutionary theory. This controversy over the significance of the Altenberg conference for the future of evolutionary science eventually reached the pages of the two most prominent science journals in the world, with an article by Elizabeth Pennisi in Science (July 11, 2008) and an article by John Whitfield in Nature (September 18, 2008).

Two books published in 2010 give us a clearer view of this controversy. Massimo Pigliucci and Gerd B. Muller, the organizers of the Altenberg conference, edited a book based on the papers coming out of the conference--Evolution--The Extended Synthesis (MIT Press). And Mazur published her book on the controversy--The Altenberg 16: An Expose of the Evolution Industry (North Atlantic Books, Berkeley, California).

Mazur's hysterical hatred of evolution is evident in the first paragraph of her book, where she writes that her book "looks at the rivalry in science today surrounding attempts to discover the elusive process of evolution, as rethinking evolution is pushed to the political front burner in hopes that 'survival of the fittest' ideology can be replaced with a more humane explanation for our existence and stave off further wars, economic crises and destruction of the Earth." Nevertheless, despite the vulgar journalism of her book, Mazur's interviews in the book do help to clarify the controversy.

From Mazur's book and from the more serious statement of the controversy in the book edited by Pigliucci and Muller, I draw two general conclusions. First, the "extended evolutionary synthesis" is not a denial of evolutionary theory, but is rather, as the term suggests, an extension of Darwin's theory and of the "Modern Synthesis" of evolutionary theory as stated in books like Julian Huxley's Evolution: The Modern Synthesis (first published in 1942 and now reprinted in 2010 by MIT press).

My second conclusion is that this "extended synthesis" of evolution needs to include sociobiology and evolutionary psychology. The title of Edward Wilson's 1975 book--Sociobiology: The New Synthesis--evokes Huxley's title, because, as Wilson argues in the book, he was expanding the Darwinian evolutionary synthesis to include the biological study of social behavior, which would include the cultural and moral evolution of human beings. Although most biologists have refrained from such a biological explanation of the whole of human life, Wilson realized that this was required to fulfill the expansive vision of Darwin himself, particularly in The Descent of Man. Although the evolutionary psychologists have adopted much of Wilson's project, it has been only in recent years that they have seen that an extended evolutionary account of life must include human morality and culture.

The Modern Synthesis of Huxley and others has dominated evolutionary science for almost 70 years. The synthesis is a combination of the Darwinian theory of natural selection, the Mendelian theory of genetic inheritance, and the mathematical models of population genetics. The core idea is that evolution occurs when random genetic mutations are selectively passed on to future generations because they enhance the survival and reproduction of organisms, and as a result, the changes in gene frequencies in a population eventuate in changes in phenotypic traits.

In their Introduction to their book ("Elements of an Extended Evolutionary Synthesis"), Pigliucci and Muller identify three restrictions imposed by the Modern Synthesis that are set aside by the Extended Synthesis: gradualism, externalism, and gene centrism.

The Modern Synthesis assumed that evolutionary change occurred through continuous and incremental genetic variation, so that discontinuous or abrupt changes were excluded. By contrast, in the Extended Synthesis, "various kinds of mechanisms for discontinuous change are now known from the domains of genome evolution, phenotypic plasticity, epigenetic development, and nongenetic inheritance" (13).

The externalism of the Modern Synthesis was the assumption that adaptation occurred primarily through the selective forces of external factors in the environment of organisms. By contrast, the Extended Synthesis shifts the weight of the evolutionary process from the external conditions of selection to the internal properties of organisms. "On this view, natural selection becomes a constantly operating background condition, but the specificity of its phenotypic outcome is provided by the developmental system it operates on" (13).

The Modern Synthesis is gene centric, because it assumes that all variation and inheritance is through genes. Although the Extended Synthesis does accept the importance of genes in evolution, it supports

the view of "genes as followers" in the evolutionary process, ensuring the routinization of developmental interactions, the faithfulness of their inheritance, and the progressive fixation of phenotypic traits that were initially mobilized through plastic responses of adaptive developmental systems to changing environmental conditions. In this way, evolution progresses through the capture of emergent interactions into genetic-epigenetic circuits, which are passed to and elaborated on in subsequent generations. (14)

Pigliucci and Muller sketch a conceptual framework for the Extended Synthesis as embracing three steps in "the continuous expansion of evolutionary theory."

The first step is Darwinism, which includes the ideas of variation, inheritance, and natural selection.

The second step is the Modern Synthesis, which includes the ideas of Darwinism but also the ideas of gene mutation, Mendelian inheritance, population genetics, contingency, and speciation.

The third step includes the ideas of Darwinism and the Modern Synthesis but also the new ideas of evo-devo theory (evolutionary developmental biology), plasticity and accommodation, niche construction, epigenetic inheritance, replicator theory, evolvability, multilevel selection (including group selection), and genomic evolution.

By thus presenting their Extended Theory as an expansion of evolutionary theory that includes Darwinism and the Modern Synthesis, Pigliucci and Muller make it clear that Mazur and the intelligent-design creationists were wrong to depict the Altenberg conference as overthrowing the Darwinian and Neo-Darwinian views of evolution. Even the most radical of the "Altenberg 16"--such as Stuart Newman--do not deny the fact of evolution or the importance of natural selection or the importance of genes. Rather, they embrace all of this, even as they argue that genetic mutation and natural selection are not the only factors governing evolution. So, for example, Stuart Kauffman and Stuart Newman argue that we need to see the evolutionary importance of the form-giving processes of self-assembly and self-organization as governed by the laws of physics and chemistry.

There is nothing here to support the claims of scientific creationism or intelligent design theory. Creationism and intelligent design require belief in what Darwin called "the theory of independent acts of creation"--the theory that the Creator had to intervene miraculously in natural history to specially create every form of life. Darwin wrote: "Authors of the highest eminence seem to be fully satisfied with the view that each species has been independently created. To my mind it accords better with what we know of the laws impressed on matter by the Creator, that the production and extinction of the past and present inhabitants of the world should have been due to secondary causes, like those determining the birth and death of the individual." Thus, Darwin was open to the thought that the laws of nature were originally the work of the Creator as First Cause, but that once those laws were in place, the natural history of the universe was governed by purely natural causes. When the proponents of the Extended Synthesis argue for expanding evolutionary theory to include various causal mechanisms of evolution that are not given enough weight in Darwinism or the Modern Synthesis, they are appealing not to "independent acts of creation," but to purely natural causes arising from the laws of physics, chemistry, and biology, which Darwin called the "secondary causes."

And yet, I see two defects in the way Pigliucci and Muller present their conceptual framework. The first is that they don't recognize that many of the ideas that they put outside of Darwinism were actually stated by Darwin himself. Darwin accepted the importance of what is today called epigenetic inheritance, because he accepted Lamarckian evolution. Although he believed that natural selection was the chief agent of change, he saw it as "largely aided by the inherited effects of habit, and slightly by the direct action of the surrounding conditions." Darwin also recognized the importance of multilevel selection. In fact, in David Sloan Wilson's chapter, he quotes Darwin as stating the idea of multilevel selection (82).

The second defect in the conceptual scheme of Pigliucci and Muller is that they don't include moral and cultural evolution and evolutionary psychology as part of the Extended Synthesis. Although this is not emphasized in their book, some of the authors do say that evolutionary explanations of human morality, culture, and psychology need to be part of the Extended Synthesis of evolutionary theory (68-71, 81-82, 91-92, 161-63, 175, 202, 209-10, 237-42, 469-70). After all, the emergence of human culture, human morality, and human intellect must be recognized as a major evolutionary transition that must be part of any evolutionary synthesis.

But, once again, I must point out that Darwin was there first! Darwin's Descent of Man presents an evolutionary account of human culture, morality, and psychology. It is remarkable that so many biologists have been so reluctant to accept Darwin's insight that any complete evolutionary science must include a science of human nature and culture.

This would also respond to Mazur's hysterical fear of evolution's corruption of morality by showing how evolutionary science can support the idea of a natural moral sense.

Some related posts can be found here, here, here, and here.


Empedocles said...

What is "non-genetic inheritance"?

Troy Camplin said...

Here's my tiny contribution to evolutionary theory:

Larry Arnhart said...


"Non-genetic inheritance" includes levels of inheritance such as epigenetic inheritance, behavioral inheritance, and symbolic inheritance. This is well covered in Eva Jablonka's account of the "four dimensions of evolution," which is the subject of a post in February, 2010.

Troy Camplin said...

And an excellent book I got sidetracked from to finish paper on Hayek's The Sensory Order and on spatial economics. Meaning I might get back to it next Fall.

Anonymous said...

"sociobiology and evolutionary psychology."

I would disagree with you, as many would. Such disciplines, as well as others like evolutionary anthropology, produced theoretical and positivist analyses based on the Modern Synthesis, on topics which we very well know that cannot be reduced to genetic inheritance. The Extended Synthesis challenges the Modern Synthesis approach, and necessarily challenges the foundations of Sociological and evolutionary psychological research.

Coming from the social sciences but keeping in touch with developments in biology, I have to say that the Modern Synthesis has been used to produce some really poor and pseudo-scientific nonsense that have real social and political implications. Much of what biologists, psychologists, physical anthropologists and psychiatrists have produced using the modern synthesis needs to be rethought from scratch, and research be reevaluated to be able to determine what significance genes actually have in relation to behavior, social structures, crime, mental disorders, sexuality and so on.