Colourful Planets

Abstract In the Myth of Er, Plato describes the ‘Spindle of Necessity’, a contraption presenting the cosmos as guided by Sirens and Fates, and ascribes different colours to the planets (Rep. 616e-617a). This paper argues that Plato probably used astronomical data for that passage, but possibly gave them a metaphorical sense, and discusses the likelihood of his having used Mesopotamian sources. The second half of the paper studies receptions of and allusions to the image, with context-based astronomical, political, and metaphysical features. Cicero adjusted the image to contemporary astronomy, and to the political function of the cosmic structures in the Somnium Scipionis. His commentator Macrobius emphasizes empirical correctness, but possibly with metaphysical undertones. Apuleius’ Metamorphoses alludes to the image in a portrait of Isis, perhaps to refer to her metaphysical role. Finally, Proclus interprets the Platonic passage as primarily metaphysical, and pointing to truths beyond astronomical phenomena.