The epigenetic landscape in the course of time: Conrad Hal Waddington’s methodological impact on the life sciences
Introduction
Conrad Hal Waddington’s epigenetic landscape (hereafter: EL) model is well-known in the history and philosophy of biology. However, it seems that the reception of his work never really gathered speed in mainstream biology—it remains an exclusive feature of those philosophically and historically informed, yet marginal recent biological debates on possible extensions of the Modern Synthesis (Pigliucci & Müller, 2010) and the role of developmental mechanisms and epigenetic inheritance in evolution (Gilbert and Epel, 2009, Jablonka and Lamb, 2005). Against this view, this paper will offer an analysis that shows when one focuses less on Waddington’s conceptual legacy (see, e.g., Gilbert, 2000, Hall, 1992, Peterson, 2011) and more on his pictorial one, what is revealed is a widespread—yet completely unrecognized—impact of his methodology throughout the life sciences. Until the late 1960s dozens of ‘landscape approaches’ emerged that applied the visual metaphor of the EL (i.e. Waddington’s originals or modified images) to highly diverse phenomena—in stem cell and evolutionary biology, but also in disciplines outside of biology such as topology, developmental psychology, science, technology, and society (STS) studies and cultural anthropology.1
In order to trace and classify these pictorial traditions (and to understand why they emerge) the following issues will be addressed: First, it will be argued that despite the conventional function of visualization, at least three further heuristic roles of EL images can be reconstructed from Waddington’s own work. They can be used (i) as tools to support transdisciplinary research (see Fagan, 2012, Gilbert, 1991), (ii) as tools to stimulate visual thought, and, most important, (iii) as heuristic tools to guide modeling efforts and theory formation. Second, based on a comprehensive evaluation of post-Waddingtonian ‘landscape approaches’ in the life sciences, this paper will show that the versatile methodological roles developed by Waddington for his original images live on in these more recent EL accounts.
Waddington’s friend and colleague Joseph Needham remarked in an obituary for Waddington, that he could “only hope that his writings and his philosophical outlook will still influence younger people for many years to come” (Needham, 1975, p. 372). To the delight of Needham, Waddington‘s legacy not only lived on, it even extended across the borders of biology. However, it is a methodological legacy, not a conceptual one—his visual metaphor has been passed on through the decades, serving as a tool box of methodologies unfolding their heuristic potential in the course of application.
Section snippets
Waddington’s landscape model in a biographical context
The scientific career of Conrad Hal Waddington (1905–1975), the leading British geneticist and embryologist in the post-molecular age, was quite unusual for a scientist whose area of specification lay within experimental biology.2 Throughout his life he was interested in problems that necessitated investigation transcending conventional disciplinary boundaries—problems alluding to philosophy, aesthetics and
The evolution of Waddington’s epigenetic landscape images
Waddington’s “simple visual model” (Waddington, 1969, p. 178) or visual metaphor of the EL, i.e. an EL image, is—similar to a linguistic metaphor—characterized by its double extensionality. That means, an EL image refers to both a primary object (here, a specific phenomenon in cell development) and a secondary object (here, a real-life landscape) at the same time. Based on ostensive reference making the visual metaphor of the EL facilitates analogical reasoning strategies and organization of
The heuristic roles of epigenetic landscape images in scientific practice
The EL images wear many hats in Waddington’s research practice. The following heuristic roles can be distinguished within his work. EL images are used as
- (i)
tools for visualization, in the sense of (symbolic) representation of a phenomenon under study and/or a theoretical concept,
- (ii)
tools for transdisciplinary communication, i.e. unification of distinct disciplines by establishing a consistent tradition of illustration,
- (iii)
creativity tools, i.e. stimulation of visual thought by art, and
- (iv)
modeling tools,
First impact: mathematization of the epigenetic landscape
During his lifetime Waddington was not able to establish a defined school as his legacy. His work did not have a more direct impact on biologists due to at least two reasons (for more, see Peterson, 2011): During the rise of molecular biology his Whiteheadian interest in processes and networks rather than discrete ‘things’, as well as his most famous EL model, were not considered in line with the thinking of the time. In addition, his work does not conform to textbook standards in biology. As
The epigenetic landscape images in the course of time
When interest in catastrophe theory came to an abrupt end in the late 1970s, the use of Waddington’s pictorial tradition seemed to have reached an impasse. However, after around 15 years being buried in oblivion, his visual metaphor was rediscovered and has been widely distributed ever since.
Conclusion
Developmental biologists David R. Newth remarks in an obituary for Waddington: “Waddington was a very unusual man, and if his influence on science was diffuse—he established no defined school as a legacy—it was certainly very widely felt” (Newth, 1975, p. 371). Waddington’s impact in the sciences during his life can certainly be understood to be rather diffuse and his posthumous influence is often considered to look not that different. Peterson (2011) lists several reasons why Waddington’s work
Acknowledgements
I thank Dan Brooks, Fridolin Gross, Jessica Pahl and Helmut Pulte for constructive comments on earlier versions of this paper and Dusa McDuff for sharing translations of Gel’fand & Tsetlin’s papers with me. I also thank the session audiences at the meeting of the International Society for the History of Philosophy of Science in Halifax (Canada) and at the RUB-Workshop in the History and Philosophy of the Life Sciences in Bochum (Germany) for feedback on presentations on this topic. Finally, I
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