How Not to Fight About Theory: The Debate Between Biometry and Mendelism in Nature, 1890–1915

Pence, Charles H. [UCL]

Evolutionary theory in the late nineteenth century was marked by controversy over the way in which Darwin’s insights could be reconciled with theories of heredity, particularly following the rediscovery of the work of Mendel. Darwin’s proposal of common descent was quickly accepted, but natural selection’s adoption was delayed as a result of this debate. Two schools of thought rapidly developed: one (the “biometricians”) using statistics to describe patterns of inheritance, and the other (the “Batesonians,” later the “Mendelians”) using morphological study and searching for discontinuous variation. The traditional history of this debate has focused on its key players (most notably William Bateson, Karl Pearson, and W.F.R. Weldon). Sociologists of science have helpfully expanded this picture to include a wider array of biologists and emphasize the role of the “conversion” of lesser-known biologists from biometry to Mendelism. In this chapter, I will expand our picture further, by considering the structure of the debate as it developed in the articles and correspondence of Nature. The “network of discourse” in this literature, as revealed by digital tools, shows us surprising features of the way this argument unfolded. Far from being a central topic in the biology literature of the day, as historians often have assumed, those arguing over theories of heredity recede into the background, engaging with fewer other members of their fields. While this digital analysis is not the end of the story, it offers us a variety of suggestive questions for future historical, philosophical, and sociological work on this crucial period in the development of evolution.