“Here I Go Again”—will Waddington’s hopes finally be fulfilled? Part I
2 April 2018
Recently, a group of biologists gathered in picturesque accommodations on the side of a mountain to discuss the Extended Evolutionary Synthesis (EES). It was a motley crew. The group included theoreticians and experimentalists, population geneticists and organismal biologists. They brought in a few participants from the humanities and social sciences to boot. Some wore ties; others, sneakers. Eating and drinking abounded. There were lively and productive side conversations. There were equations. There was even snow.
All of these things just happened at the Santa Fe Institute in February 2018. But I’m speaking instead of the International Union of Biological Scientists (IUBS) meetings that took place in the Rockefeller Foundation’s mountain-hugging Villa Serbelloni in Bellagio, Italy, a half-century ago (“recently” by any historian’s estimation). British embryologist/geneticist C. H. Waddington (1905–1975) organized those meetings because he was disappointed that the existing evolutionary theory—then called the Modern Synthesis or neo-Darwinism—seemed not to account for the most important problems in biology. Chiefly, he wondered how one accounts for organismal complexity in the face of initial simplicity. Development and evolution were the obvious answers. But what did these terms really mean and how were they connected? Were they just the unrolling of preformed genetic instructions, as the 1960s narrative specified? From 1966 to 1969, Waddington gathered dozens of biologists and allied scholars at Villa Serbelloni to discuss how to extend the evolutionary synthesis by more closely examining these issues.
Waddington ensured the IUBS meetings had a balanced tone. Invited speakers included several, including Francis Crick and John Maynard Smith, who were not sympathetic to the argument that the evolutionary synthesis needed to be extended. Other meetings held at the same time weren’t as even keeled. Hungarian-Austrian-British intellectual Arthur Koestler (1905–1983) convened another conference focused on extending the evolutionary synthesis at Alpach, Austria, in 1968. Waddington joined Koestler’s circle of luminaries, including Jean Piaget, Ludwig von Bertalanffy, Frederich A. Hayek, Paul Weiss, and Viktor Frankl, among others. But here, unlike at the IUBS meetings, Waddington found the whole of Darwinism and genetics under attack. He regarded an extended evolutionary synthesis as due in the immediate future, already underway, in fact. The question Waddington pondered was how to keep the baby of evolutionary biology while throwing out the bathwater of metaphysical reductionism?
I am keenly interested in how the social structure, intellectual concepts, traditions, and methods in the discipline of biology functioned a half-century ago to create or undercut consensus around an issue as vast and important as our explanations of development and evolution. I also wonder how they are operating today. Studying the broad contours of this history of evolutionary, developmental, and ‘inheritance’ biology has led me to a set of five questions. I’ll briefly attempt to synthesize a miniscule portion of the fifty years of work in the history and philosophy of biology that separates us from Waddington’s era to try to address several of these questions.
Question 1: How did the split between development and inheritance come about?
Answer 1: Genetics & embryology fell naturally into an existing mechanism-vitalism dichotomy.
The mechanism-vitalism debate has a centuries-long history that mainly took place within the confines of embryology. But by the mid-19th century, the terms of that dispute changed. The Berlin Physical Society founded by Hermann von Helmholtz and Emil du Bois-Reymond, among others, committed to scrub vitalism out of the life sciences. They inspired the work of Wilhelm Roux known as Entwicklungsmechanik or developmental mechanics. And it was out of Roux’s school that Hans Driesch emerged with his sea urchin work.
Driesch (1867–1941) used these developmental mechanics experiments as evidence in his call for the renewal of vitalism. It just so happened that his campaign for vitalism—which was picked up by other major theorists including Henri Bergson, Oscar Hertwig, and William MacDougall (inspirations to Koestler, incidentally)—coincided with the rediscovery of Mendel’s work and the birth of genetics. Early Mendelians, even those originally trained in embryology, saw their new research as more in line with the principles outlined by the Helmholtz program rather than that of Driesch. As one of them, William Bateson described it, he left research on development in the 1890s because he felt his embryology professors operated as craftsmen or artists preoccupied with aesthetically pleasing depictions of properly mounted and stained embryos and were still fighting old battles about common descent. His new generation of geneticists wanted to explore universal laws using quantitative data, like physics. Genetics was new and exciting. Embryology was just uncool—it belonged to the peculiar and stuffy natural history tradition of the 19th century. And it countenanced vitalism. So, these first geneticists elected to bypass embryology to study inheritance indirectly through population genetics. Once Walter Sutton and Theodor Boveri independently observed the correlation between the segregation of Mendel’s units of inheritance and the behavior of chromosomes at meiosis—thereby inferring that genes were discrete particles strung on chromosomes—Mendelism achieved a new kind of caché. More and more features in biology seemed able to be explained in terms of the actions of genes.
There is more to it than just trendiness, of course. As historians Gar Allen, Bob Kohler, Jane Maienschein, Evelyn Fox Keller, and others have emphasized, genetics just moved faster. The model organisms bred faster. And the rules that applied to one organism were applicable to other organisms. So, the split between developmental biology and genetics was messy from the beginning—it was socio-cultural and methodological, and it also mapped easily onto an existing philosophical dispute about the nature of life.
It’s easy to overlook just how important and long lasting that philosophical piece was to this story, to believe that once the methodological hurdles were cleared that the divisions between the studies of development and inheritance would fall away. But even as major figures worked to close the divide between embryology and genetics in the late-1920s and early-’30s, the old philosophical fractures remained. We can see them even in the major first attempt to pull the two subfields together.
This is a three-part miniseries:
Part I (this post): How did the split between development and inheritance come about?
Part II: How did biologists attempt to mend the split between development and inheritance in the past?
Part III: Why didn’t Waddington’s attempts to fix the division between development and inheritance work?