Palmieri and Vesel on Symmetry and Harmony in Copernicus' Cosmology

Bernard Goldstein, Giora Hon
In his review [Aestimatio 11 (2014) 188-190] of Matjaž Vesel's book, 1 Paolo Palmieri focuses on the question 'What does Vesel mean by "Platonism" and can it be neatly defined in the context of European culture of the 16th century?' According to Vesel, as reported by Palmieri, harmonia and sym-metria are two key concepts whose applications in De revolutionibus (1543) show Copernicus to be a follower of Plato. In this brief note, we seek to clarify Copernicus' explicit invocations of symmetry
more » ... ions of symmetry and harmony in his De revolutionibus. Palmieri paraphrases part of the author's argument: His [Copernicus'] central argument for the Earth's motion is, therefore, the firm symmetria of the universe, that is, the commensurability of its parts.... It is true that 'symmetria' in Euclid's Elements means commensurability but the context of Copernicus' usages indicates that the references in De revolutionibus are to the Vitruvian sense of well-proportioned as an aesthetic category rather than to a mathematical category [Hon and Goldstein 2004]. Both meanings of 'symmetria' are well attested from Antiquity to the 16th century-and even later. 2 1 M. Vesel, Copernicus: Platonist Astronomer-Philosopher. Cosmic Order, the Movement of the Earth, and the Scientific Revolution. Frankfurt am Main: Peter Lang, 2015. 2 Indeed, both meanings of 'symmetria' can be found in the works of Plato: see Hon and Goldstein 2008, 70 and 94-95.