Conrad H. Waddington: Towards a Theoretical Biology

A founding member of the Theoretical Biology Club, Conrad Hal Waddington was a pioneering theoretical biologist who was, in his own words, inspired by the philosophy espoused by the philosopher and metaphysician Alfred North Whitehead: “Thus my particular slant on evolution—a most unfashionable emphasis on the importance of the developing phenotype—is a fairly direct derivative from Whiteheadian-type metaphysics” (cited in Robertson 1977: 597). As a consequence, the phenotype was, for Waddington, a process—a concept that has more recently, with the advent of the present-day version of evolutionary developmental biology, gathered much attention. Waddington’s interest in theoretical biology, first fostered in the Theoretical Biology Club—whose members included embryologist Joseph Needham and his wife the biochemist Dorothy Needham, the biologist turned philosopher Joseph Woodger, the physicist (and some say “father of molecular biology”) John D. Bernal, the cell biologist E. Neville Willmer (long-time editor of Biological Reviews and author of the first book to comprehensively discuss the evolution of cells [Willmer 1970]), and the future Nobel Laureate Peter B. Medawar—found its most pronounced manifestation in his editorship of a four-volume series entitled Towards a Theoretical Biology (1968–1972, hereinafter, TTB). These volumes were the proceedings of four International Union of Biological Sciences (IUBS) meetings Waddington organized in the late 1960s and early 1970s at the Villa Serbelloni in Bellagio, Italy. Chance attendance at the IUBS general assembly in Amsterdam in July 1961 had resulted in Waddington being asked by the internationally renowned developmental biologist Paul Weiss to stand for President of the Union, an office that Waddington put to good use in advancing an in-depth and wide-ranging discussion on the theoretical and conceptual foundations of biology. We use this introduction to place into a conceptual context four of Waddington’s papers from TTB. The four papers, along with commentary on one of them (from TTB, Vol. 4) are reproduced in this issue. In addition, we also briefly discuss two papers published by Waddington in the journal Nature in 1941 and 1942. These are not reproduced here, but are readily available online in the digital archive of Nature or in Waddington’s collection of essays, The Evolution of an Evolutionist (Waddington 1975). These two papers together with Waddington’s seminal book Organisers and Genes (Waddington 1940) mark the beginning of Waddington’s theoretical and conceptual work on a causal theory of both development and evolution focused on the organism as, to use a current concept, a complex dynamical system. One of these papers lays out his thoughts on how developmental systems evolve, a topic that has come into considerable prominence and importance over the past decade. The second is a short but seminal paper on Waddington’s concept of canalization. The four papers reproduced here represent the core themes of TTB that are most connected to current conceptual discussions in evolutionary developmental biology. Our intention in making these papers available to a wider audience of theoretical biologists and by juxtaposing them with papers discussed at the Altenberg workshop is to stimulate discussions that take full advantage from the encounter of current problems with historical antecedents.