Abstract

R.A. Fisher’s The Genetical Theory of Natural Selection, first published by Oxford’s Clarendon Press in 1930, has a mixed legacy. Its opening chapters, analysing various evolutionary scenarios from a combined Darwinian-Mendelian perspective, are widely celebrated today for their role in laying the theoretical foundations of the so-called ‘modern synthesis’. Its closing chapters, meanwhile, are notorious. Across more than one hundred pages, Fisher provides an extended meditation on eugenics, in which he attempts to explain the collapse of ‘great’ civilisations, past and present, in terms of the overzealous breeding of the ‘undesirable’ lower classes. In this talk I will examine how such a book of ‘two halves’ came to be. Drawing upon previously unstudied archival evidence, I will reconstruct the authorship of this now classic scientific text, overturning long-held ideas about the timing and order of the book’s composition. Doing so not only reveals new insights about the writing and reading of evolutionary science between the Wars; it also recasts a decades-long scholarly dispute regarding the relationship between Fisher’s eugenical commitments and his scientific contributions, at a moment when his legacies are being actively debated once more.