The atmosphere in Palais des Congrès in Versailles, France, was electrifying, not to say euphoric: On 16 November 2018, the 26^th General Conference on Weights and Measures (CGPM) issued a new definition of the kilogram. This replaced the orientation to the Parisian prototype, the “last remnant” of the old metric system. Since that day, all measures are based on universal natural constants. The scientists from 54 different nations unanimously passed the resolution. Here, they jointly put their faith in procedures and instruments that only a very few of them could actually replicate or use. In this way, they realized the dream of unity that had previously failed to come about on repeated occasions in the history of science. Prof. Lorraine Daston explores this dream. Her new publication is the extended version of a lecture that the historian of science gave last September on the occasion of being awarded the Gerda Henkel Prize. (Lorraine Daston, The Dream of the Unity of Science, Gerda Henkel Lecture, Münster, 2023).

In her piece, Director emerita of the Berlin Max Planck Institute for the History of Science describes three historical attempts to realize the dream of the unity of science. She shows that different versions of this dream are involved. The publication also includes a discussion between Prof. Daston and art historian Prof. Peter Geimer (Paris) that took place as part of the prize-giving ceremony. The topic is the colourful history of scientific illustrations – from artistically imbued illustrations through to the immense project of creating a high-tech representation of a Black Hole. Because people need images. Humans are the species, Lorraine Daston comments, “that think with images”.