Christian Platonism is a catch-all phrase. It recognizes that Plato and his successors, including the whole of ancient pagan thought, formed part of the complex background to the emergence of a new religion. Both pagans and Christians were mutually transformed by their prolonged encounter on many issues, but especially on the questions of creation, desire, and return. The chapter begins with Judaeo-Christian influence upon major features of the Platonic tradition and then articulates a hidden conversation that lies behind Christian thinking about the Trinity, the structure of reality, and the creation of the human being.

The last part of Chapter 2 and the first part of Chapter 3 of De mundo (392a31–393a8) describe the cosmic layers further below the sphere of the moon, leading down to the very centre of the universe. This section provides a brief overview of the sublunary layers of the four elements (fire, air, water and earth), some of which will be discussed in more detail later in the text. The two main theses that constitute the reasoning behind this section are (i) continuity throughout the entire cosmos and (ii) the great variety of phenomena and processes within the sublunary domain. The layers are organised from the most active one at the top down to the most passive one at the centre of the universe. The continuity among the layers is demonstrated on each and every level. There is, however, no suggestion that each lower, less active substance gains all its characteristics from the more active substance above. For our author’s purpose it is sufficient to demonstrate that there is some relation, some communication among the layers which can later be used by the divine dunamis permeating the entire cosmos. The final part of the present section concerns the claim that the continents are large islands surrounded by an ocean.

This chapter explores the protean character of Christian Platonism in the Romantic Age. If the Enlightenment was frequently shaped by a critique of dogma, tradition and superstition, the Romantics were concerned with the loss of culture, the exaltation of abstract reason, and a longing for the transcendent. Platonism offered a means for revitalizing Christianity, caught between the cultured despisers of religion in the Enlightenment, and the annexation of creation to the mechanistic thought of the emergent natural sciences.

This essay treats of the (Neo)platonic influences in the thought of Thomas Aquinas, in particular the notion of participation. It describes Aquinas’ doctrine of participation in being as developed from his principal Neoplatonic sources, to wit, Boethius’ De hebdomadibus, Dionysius’ De divinis nominibus, and the Liber de causis. It argues that the doctrine of creation in terms of participation the Christian conditions of creation.

Christian Platonism has the capacity to serve as a resource for addressing the present-day environmental crisis. Drawing upon a diverse range of thinkers, including Augustine, Aquinas, Hildegard, Traherne, Coleridge, and Novalis, the chapter illustrates how the tradition envisions a non-anthropocentric conceptualisation of nature.

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.