17. Cosmic Distances: Aëtius 2.31 Diels And Some Related Texts

Abstract

In the Doxographi Graeci the preferred short heading of Aet. 2.31 (Greek text below, p. 28) is 'On Distances', though ps.Plutarch has a long heading. This chapter is about the distances of the sun and moon from each other and from the earth (lemmas 1 to 3, in both ps.Plutarch and Stobaeus), and of the real or apparent shape of the heaven relative to its distance from the earth (lemmas 4 and 5, Stobaeus only). Parallels from Ioann. Lydus and Theodoret for what is in ps.Plutarch are given by Diels in apparatu. To the best of my knowledge it has not been noticed that a version of ps.Plutarch's text is preserved in a scholium on the Almagest, which constitutes our earliest evidence for the text. The correctness of Diels' reconstruction is questionable. Though certainty, naturally, is beyond our reach it is quite possible that these two sets of lemmas represent two distinct Aetian (or proto-Aetian) chapters. These may have been coalesced by Stobaeus (or Aetius), while ps.Plutarch abridged the second (or the two final lemmas) away. These considerations necessitate an inquiry into the parallels that are available, including material from an introduction to Aratus. The vexing question of short versus long(er) chapter headings is also relevant in this context. Furthermore, the contrasting views regarding cosmic distances are not only a feature of the Placita literature with a distant origin in Aristotle, but also, apparently, of the commentary literature on Plato's Timaeus. Arguably in a passage in Plutarch's De facie these two traditions intersect. Finally, a case can be made out for Eudemus not Theophrastus as an intermediary source of Presocratic astronomical data in the Placita.