Scientific Realism and the Divide et Impera Strategy: The Ether Saga Revisited

Using the optical ether as a case study, this article advances four lines of consideration to show why synchronic versions of the divide et impera strategy of scientific realism are unlikely to work. The considerations draw from (a) the nineteenth-century theories of light, (b) the rise of surprising implication as an epistemic value from the time of Fresnel on, (c) assessments of the ether in end-of-century reports around 1900, and (d) the roots of ether theorizing in now superseded metaphysical assumptions. The typicality of the case and its impact on diachronic versions of the strategy are briefly discussed.