Since the early days of its professionalization, in the aftermath of the Second World War, the history of science has been seen as a bridge between the natural sciences and the humanities. However, only one aspect of this triadic nexus, the relations between the history of science and the natural sciences, has been extensively discussed. The other aspect, the relations between the history of science and the humanities, has been less commented upon. With this paper I hope to make a small step towards redressing this imbalance, by discussing the relationships between the history of science and two other humanistic disciplines that have been historically and institutionally associated with it: the philosophy of science and general history. I argue that both of these relationships are marked by the characteristics of an unrequited friendship: on the one hand, historians of science have ignored, for the most part, calls for collaboration from their philosopher colleagues; and, on the other hand, historians specializing in other branches of history have been rather indifferent, again for the most part, to the efforts of historians of science to understand science as a historical phenomenon. I attempt to offer a diagnosis of this regrettable situation and a suggestion for overcoming it.

Theory and experiment went hand in hand in the work of Lord Rayleigh, in which the quest for rigor was a ubiquitous theme. To Rayleigh’s mind, though, and in contrast to mathematicians, physicists could proceed in their investigations without seeking absolute rigor. In his experimental practice, pursuing rigor involved the application of control strategies, which pervaded his work at various levels. Moreover, experimental control had various aims, such as standardizing measurement units in determining the ohm and validating experimental results in the discovery of argon. In the former case, Rayleigh and his team varied the design of their apparatus to control the experimental conditions. Dealing with errors was the main aim of their control practices and lay at the heart of their methodology. In the latter case, control was present in every step of the discovery process: the detection of discrepancies between the densities of atmospheric and “chemical” nitrogen, the identification of argon as a constituent of the atmosphere, and the subsequent exploration of its properties. The aim of this paper is to investigate and contrast the strategies of control employed in those two cases and to clarify their various purposes.