The Music of the Spheres from Plato to Boethius: on the Audibility and Inaudibility of Music

The theory of the harmony of the spheres has a Pythagorean origin: an askousma reported by Iamblichus seems to refer to it (VP 81 = DK 58 C 4, 19-20), and both Porphyry (VP 30) and Iamblichus (VP 65) speak of ‘the universal harmony of the spheres and the stars that move with these’. This theory is discussed at length in Plato’s myth of Er (Republic 10. 616b–617d), but rejected by Aristotle (On the Heavens 2.9.12). Proclus discusses Plato’s myth of Er, dwelling on the musical implications of the myth of Er (Commentary on Plato’s Republic, 242–243). Boethius (On the Principles of Music, 1.187-188) lays out the relations between the music of the spheres which is inaudible to human ears (musica mundana), the harmonies of a correspondingly well-ordered human life (musica humana), and the music of instruments (musica instrumenta constituta): humans mediate between the perfect harmonies of the heavenly spheres and the chaos and disorder of the lower worlds. In my paper, I will focus on how the music of the spheres is described as audible by Plato and as inaudible by Proclus and Boethius, and on the philosophical and cosmological implications entailed by this fundamental difference. In Plato’s myth of Er, the afterworld is described as a landscape characterized by loud acoustic allurements: it is shaken by the rumble of the Tartar and enchanted by the heavenly melodies of the Sirens and the Fates. The heavenly harmony depicted by Plato derives from the encounter between the Sirens’ harmonia and the Fates’ songs. The Sirens’ and the Fates’ concert is so captivating that it generates a strong temptation to grasp it by ‘listening to it’ with human ears. The text makes it clear that harmony is a sonorous music and not a sort of conceptual arrangement of the heavens based on abstract music theory. The movements of the heavenly bodies are meant to produce audible effects, and this audible music is conceived of as pleasant (see also Timaeus 35a–36d, a passage which shares numerous astronomical and musical analogies with the system described in Republic 10). In his Commentary on Plato’s Republic, Proclus claims that the Fates sing ‘intellectually’, and that this song, though in itself inaudible, produces a perceptive act. Thus, the soundless movement turns into sound, and Er hears what he has previously grasped through the intellect. Proclus clearly identifies the essence of the heavenly harmony as a pure intellectual reality; nonetheless, he recognizes that it has a sensible expression: it is the way in which the intellective activity of the Fates becomes perceptible. In On the Principles of Music, Boethius asserts that man possesses music as an innate quality that reverberates within our body and spirit; by devoting himself entirely to the theoretical study of music (musica mundana), man eliminates the possibility of a demoralizing influence of music. The music of the spheres is the type of music that ‘is discernible especially in those things which are observed in heaven itself or in the combination of elements or the diversity of seasons’. It is an inaudible music, which results from the proportion and harmony of the celestial bodies. At the core of this idea stands ‘a fixed sequence of modulation that cannot be separated from this celestial revolution’. According to Boethius, musical and cosmic structures express the same mathematical ratios, as each of the planets produces an inaudible sound in its revolution and the combination of these sounds themselves forms a well-defined musical scale. The paper will provide a close reading of the relevant passages by Plato, Proclus, and Boethius. I will focus on the analogies and the differences between their different accounts, and show how a comparative reading of them enables to gain significant insights into the ancient (Pythagorean, as well as Platonic and Neoplatonic) idea of the music of the spheres.