After considering On Breaths’ “Gorgianic” style and the disputed attribution of this text to Hippocrates, this chapter argues that the author’s attribution of all diseases to pneuma is not as revolutionary as it initially appears. By relying on widely attested views about what pneuma tends to do within the body, this author is in fact remarkably conservative when constructing his own theories of pathogenesis. This chapter then turns to the more important question of why this author felt compelled to identify a single cause of all diseases. On the one hand, we can point to the same interest in remote and proximate causes that we see in On the Nature of the Human Being. At the same time, this author seems to be driven by a separate “cosmological impulse,” the belief that high-level commonalities, whatever their applicability, are inherently desirable and directly relevant to the medical art.

The chapter focuses on the role of the heart and the image of the world as a cardiovascular system in the post-Chrysippean tradition. Within this picture, then, it will be shown that in later Stoicism, not only the heart but the blood first and foremost was used in explaining the essence and features of the soul and eventually employed as a model to explain the universe. The existence of a ‘hematic’ variation within cardiocentrism will thus be highlighted, which allows some Stoics to better justify the spreading and the action of the soul within the body, and that of god throughout the cosmos. By doing so, the post-Chrysippean tradition recalls Empedocles’ position. This topic will be first of all studied in Diogenes of Babylon, who stresses the importance of the heart in the wake of his master Chrysippus, yet apparently providing a different definition of the soul as (made of) blood. The chapter examines then Posidonius, whose cardiocentrism – though not strictly ‘hematic’ – differs from that of both Aristotle and Chrysippus and is crucial for his understanding of living beings and natural phenomena. Lastly, the contribution considers Seneca and Manilius, who often represent the universe as a cardiovascular system enlivened by a network of blood vessels.

The chapter presents an investigation into the Presocratic background of soul theories, more specifically, the relationship between fire and soul in Empedocles. Trépanier argues that Empedocles fragment B 9 does not give us a positive account of fire as soul, but targets a rival Presocratic account of fire as soul.

Thein provides a detailed analysis of Aristotle’s analogy between “the phusis in the pneuma” and “the element of the stars” in Aristotle’s GA (736b29–737a7). With the help of several passages in GA which discuss the role of pneuma in the generation of living beings, as well as passages of De caelo, where the first body is presented as an animate, self-moving but soulless entity, Thein makes the case that the key to the analogy lies in the shared link between motion and animation, a link which, in these two cases only, does not require the actual presence of the soul.

Reece discusses Diogenes of Apollonia’s claim that “all existing things are differentiated from the same thing and are the same thing” (DK 64B2, Simp. Phys. 151.31–32), namely air. He examines Diogenes’ principle that causal interaction and change require some sort of uniformity among the relata, and considers the questions which this principle raises.

Gelber focuses on passages in GA where Aristotle treats heat and cold as agents which are said to be making (poiei), fabricating (dêmiourgei), solidifying (pêgnutai), putting together (sunistatai), or working (ergazetai) to accomplish something, and thereby playing a role in the formation of a living organism. Gelber s aim is to explain how heat and cold do this, and the significance, for Aristotle, of calling heat and cold the tools of soul in his explanation of animal reproduction.

Macfarlane highlights Aristotle’s use of the concept of pathological pneuma, which reveals Aristotle’s connections with the medical ideas current in his time. Macfarlane’s analysis casts new light on this connection, the difference between respired and connate pneuma, and on the relation between connate pneuma and blood.

This chapter concerns the medical background of Aristotle’s accounts of heat, pneuma, and the vegetative soul. Bartoš discusses four Hippocratic texts (namely On Flesh, On Regimen, On Sevens, and On Winds) in which heat/fire plays a prominent role. He illustrates the relation of the notion to soul and pneuma in these texts and suggests several remarkable details of special importance to Aristotle’s zoology.

King explores the reflection in both Plato and Aristotle on styles of causal explanation in the explanation of nature, and examines several texts in which they react to theories of natural necessity in this context. He also reviews the influence of Werner Jaeger’s scholarship on the question of Aristotle’s relation to authors in the Hippocratic Corpus.

Roreitner scrutinizes Aristotle’s physiological description of perceptual processes, for which two alternative interpretations have been advocated in the past: it is either pneuma or blood which secures the communication between the peripheral organs of distal senses and the central organ. Roreitner assesses both these traditional interpretations and provides a third alternative according to which it is the body of blood-vessels rather than their content which provides this communication.

Lewis suggests an interpretation of the text which aims to identify the author’s views on the role of heat in animals and to answer question such as (i) What are the roles of heat in the composition and functions of the animal body? (ii) By what means and with the aid of which substances or structures does heat perform its roles? (iii) What is the relation between heat and the soul and heat and pneuma? (iv) Is there an “innate heat” in the body?

This chapter traces a genealogy of pneumatic cosmology, covering the Pythagoreans of the fifth century BCE, the Stoics of the third and second centuries BCE, the Jews writing in Alexandria in the first century BCE and the Christians of the first century CE. Starting from the early Pythagoreans, ‘breath’ and ‘breathing’ function to draw analogies between cosmogony and anthropogony – a notion ultimately rejected by Plato in the Timaeus and Aristotle in his cosmological works, but taken up by the Posidonius and expanded into a rich and challenging corporeal metaphysics. Similarly, the Post-Hellenistic philosopher and biblical exegete Philo of Alexandria approaches the cosmogony and anthropogony described in Genesis (1:1-3 and 1:7) through Platonist-Stoic philosophy, in his attempt to provide a philosophically rigorous explanation for why Moses employed certain terms or phrases when writing his book of creation. Finally, the chapter sees a determined shift in the direction of rejecting pneumatic cosmology for a revised pneumatic anthropogony in the writings of the New Testament: by appeal to the ‘Holy Spirit’ (πνεῦμα ἅγιον), early Christians effectively adapted the Stoic metaphysics of ‘breath’, with its notions of divine intelligence and bonding, to the ecclesiastical project of building a Christian community conceived of as the ‘body of Christ’.