This part of Chapter 2 offers two definitions of ‘cosmos’ and then describes the latter as a whole containing the largest stable structures composed of the five elements: aether, fire, air, water and earth. It explains the division of the cosmos into the upper or supralunary part, which is made of aether and where things are incorruptible and in regular circular motion, and the lower or sublunary part, where things are diverse and less regular, composed of the remaining four elements, and subject to constant generation and corruption. The perfect supralunary part forms a system of concentric rotating spheres. While the fixed stars all move ‘on one visible surface of the whole of the heavens’, where they keep their position, the planets are simply said to each move in their own orbit, with no explicit mention of the higher number of moving spheres posited by Eudoxus or Callippus. Below the lowest planetary sphere, that of the Moon, the sublunary part of the cosmos begins. It is also organised in concentric spheres, each one dominated by one of the four elements, starting with fire and ending with earth in the immobile centre of the universe. The author pays special attention to the immutable aether that belongs to the causal chain extending from God to all the motions in the earthly region of the universe. In virtue of its physical perfection, the ether is indispensable for God’s guidance and administration of all heaven and Earth.

In the seventh and last chapter of De mundo, the author discusses the many names of God, which reflect the various effects God produces in the world (401a12–27). In line with the predominantly Aristotelian background of the author, it is claimed that these effects are not caused by God directly, but by his power (dunamis). This approach helps explain various traditional names, epithets and functions assigned to Zeus in Greek religion and mythology, including names which refer to meteorological phenomena and epithets related to cosmology, but also, perhaps more surprisingly, to human affairs. In this respect, as a detailed comparison shows, the chapter is clearly inspired by various Stoic authors. The central place of the chapter is occupied by the famous Orphic hymn to Zeus. A detailed interpretation of the hymn shows that it is in many ways compatible with the philosophical outlook of De mundo. However, the hymn also features parallels with the Orphic theogony commented upon in the Derveni Papyrus and its later version, which was quoted by late Neoplatonists. The comparison reveals various similarities and differences between these three texts and supports a hypothesis according to which the author of De mundo omitted some parts of the original Orphic theogony. Traces of the missing verses, however, can be seen in the subsequent section (401b8–29), where Fate is discussed. This interconnection helps us to better understand both De mundo and the Derveni Papyrus.

In the first sentence of his Harmonics Ptolemy offers a definition of the science to which his work is devoted, and – rather surprisingly – it contains nothing to indicate that Harmonics is concerned, specifically, with matters to do with music. On the contrary, the definition seems to say that it is concerned with sounds of all sorts, insofar as they differ from one another in pitch. We know, of course, that in fact the work does indeed focus almost exclusively on musical issues, but it turns out that Ptolemy does not narrow his perspective in a way that excludes further treatment of non-musical sounds until the closing stages of his fourth chapter. This chapter discusses the way in which he achieves the transition between the broader and narrower fields of investigation, while still holding fast to the definition from which he began.

From the very early treatises, Plotinus highlights that the perception of harmonies and rhythms could lead up to the grasp of intelligible harmony. While Plotinus abandons the link between music and astronomy, distinguishing himself from the general reading of Plato developed in the imperial era, he stresses the psychagogical dimension of music. On the one hand, he simplifies the analyses devoted to music as a preparatory discipline, but on the other, he draws upon examples from the arts of rhythm (namely dance and music) to illustrate key aspects of his cosmology and of causal processes. After reviewing the place of music in Plotinus’ metaphysical organization, this chapter examines the use Plotinus makes of images related to music, dance and rhythm to exemplify different causal relationships. It concludes with an analysis of the meaning of a hapax, the adjective arrhythmistos taken from Aristotelian doxography and initially associated with the primordial indetermination of matter. These considerations lead to the conclusion that, in the Enneads, the concept of rhythmos goes beyond the field of musical arts and denotes the dynamic productivity of intelligible realities.

This chapter explores Plato’s negotiation of friendship, and similar modern considerations, particularly those of Kant and Derrida.It suggests that Plato, far from advocating an abstracting position in opposition to Christian love, prepared the way for the gospel insofar as he tended to show that love and knowledge were inseparable, even at the highest level.

Ficino’s Christian Platonism is characterized by two overriding features. First, it is expressed in works that are elaborated along traditional medieval lines in the form of commentaries either standing alone or incorporated into writings in other genres. Second, the configuration of this Platonism is inseparable from the history of Platonism as a tradition embodying both a continuous progress towards the light and a rhythmic alternation of revelation and concealment. After exploring this material in detail, it will become clearer how Ficino’s Christian Platonism is at the same time a psychology and a theology grounded in a sort of two-directional hermeneutic. Plato the non-Christian writer is prophetic of his own reading by later non-Christian Platonists who acquired the possibility of this reading on the one hand, through their partial illumination by Christian intermediaries and on the other, through their judicious distinction between the literal truth and non-literalness of some of the master’s most important teachings.

This chapter calls into question the longstanding notion that early Franciscans simply systematized or rehearsed ideas from Augustine and highlights instead how they employed Avicenna and Arabic philosophy to forge a completely new understanding of the bishop’s thought. Although this version of Augustinianism was initially passed off as a reading of the Aristotelian tradition as well, it became disassociated with Aristotle as the next generation came to a more authentic understanding of the Greek philosopher’s thought. By contrast, the Augustinianism invented by early Franciscans continued to be widely promulgated and defended for generations and thus impacted conceptions of Christian Platonism that remain influential to this day.

In this chapter I discuss the paradigmatic function which music, as a theoretical science (‘harmonics’), can have in relation to practical philosophy, in particular ethics, for the Platonists of Late Antiquity, going from Iamblichus (end of the 3rd century) and Proclus to Damascius (mid 6th century). Inspired by some passages in Plato’s Republic, in Nicomachus of Gerasa and in Ptolemy’s Harmonics, these Platonists also introduced a hierarchy of types of music and a hierarchy of types of virtue. I will attempt to show the relation between these two hierarchies, starting with the ‘ethical’ and ‘political’ levels of virtue, showing how harmonics provides conceptual paradigms for the description of these virtues, and then moving up to the higher levels of virtue, the ‘purificatory’ and ‘theoretical’ virtues, asking how music, as harmonics, might relate to the higher virtues.

The distinctive features of Plato’s philosophical system are examined, especially his rejection of naturalistic philosophic and scientific approaches and his postulation of an absolutely simple first principle. The Platonists after Plato are then considered, including Aristotle, Alcinous, Numenius, Plotinus, Iamblichus, Proclus. Platonism is conceived as a collaborative project that developed over against opposition – such as Stoicism and, in late antiquity, Christianity – as well through internal debates among its rival schools. The chapter concludes with a discussion of Platonism’s encounter with Christianity after the Edict of Milan.

Philo’s interest in music is as known as it is overlooked in its philosophical implications. This chapter focuses on the importance of the musical paradigm in Philo’s thought and its relation to the other complementary model adopted by the philosopher: the pattern of the scala naturae, inherited from Stoicism. More specifically, Philo’s appeal to the notion of harmony introduces the idea of some orderly discontinuity in nature, implying both the transcendence of God and the limited condition of human rationality: the world is indeed governed by harmony, but only in the very qualified sense that it implies harmonically defined relationships between very distant entities. This ‘vertical’ harmony, however, is combined with a ‘horizontal’ one, for God also exerts his providence through harmony, while, in turn, music is the intellectual means by which man can contemplate the heavens and draw closer to God. These are not mere metaphors, for music represents a proper philosophical model for Philo that he applies to aspects which will prove fundamental in the post-Hellenistic age.

The relation of early Christianity to ancient Platonism has been a conflicted issue in historical scholarship, bringing to the fore latent questions about the nature of philosophy and shape of Christian theology. This chapter is intended to build upon recent advances in the scholarly interpretation of both Platonism and Early Christianity, in order to disentangle some long-standing interpretive issues. It emphasizes the role of Platonism and Christianity in the emergence of monotheism in late antiquity and the importance of Platonism in the development of the philosophical idea of transcendence.

The first chapter of De mundo sets the tone and object of the treatise and aims to capture the reader’s attention with highly polished rhetoric, admittedly worthy of an address to Aristotle’s most famous pupil, Alexander. It advances the claim that philosophy is a divine matter because it deals with eternal, divine truths. Unlike specialised sciences, which study one or more parts of the universe in isolation, philosophy seeks to appreciate the universe as a harmonious, well-ordered whole. However, without understanding God and the way he is related to the world, the essential features of the world – its order, unity, eternity, beauty and goodness – cannot be appreciated. For this reason, the author of De mundo urges his addressee – Alexander, ‘the best of leaders’ – to pursue philosophy, which amounts to studying the universe as an effect of God and, in this sense, to theologise. This is a conception of philosophy that the author of De mundo seeks to ascribe to Aristotle.