Ancient philosophers believed that biology and cosmology are two sciences that intersect one another insofar as biological concepts explain crucial features of the cosmos and, conversely, cosmological concepts account for important biological properties and events. ‘Cosmobiology’ is the term that I shall use to refer to this view. The aim of this introduction is to present some central cosmobiological theses in antiquity, to describe how the present volume is organised, and to offer a brief overview of the chapters.

In metaphysics, Avicenna refers to the heaven as animal (ḥayawān), and to its proximate principle of motion as soul (nafs), by using the same terminology used in psychology to refer to sublunary animals and their principle. The strategy behind this approach is to account for a remote phenomenon, i.e. heavenly circular motion, through the account of an analogous but closer and thus more knowable phenonemon, i.e. animal locomotion. Thus, in metaphysics, a sort of continuity between sublunary and celestial ‘animals’ seems to be posited: both are defined by means of the same terminology and share in some distinctive features. However, in psychology, where this terminology is defined, Avicenna explicitly denies that sublunary and celestial ‘animals’ can be referred to in the very same way, except by equivocation. This position rests on the discontinuity between the sublunary and celestial realms that is posited in psychology. Given that Avicenna’s attitude towards this issue is not consistent, the aim of this chapter is to shed some light on the use of the terms animal and soul in psychology and in metaphysics, in order to ascertain whether they have the same meaning when they are applied to celestial and sublunary entities.

The chapter explores how the Stoics account for the totality of movement in the cosmos – in other words, the agency of the world. The Stoics take the world to be a complex and divine living-being. Their physics combines what today we might call physics, biology and theology. The Stoics put forward two premises that appear to be in tension. First, they claim that the active principle is the sole source of movement and cause of everything. Second, they offer a scala naturae according to which kinds of entities differ by the way in which they move and jointly co-cause all movement in the world. This One-Many Problem is the Stoic version of what is later called the problem of free will and determinism, or so I argue. As the Stoics conceive of the problem, the challenge consists in showing how both premises – One Cause and Many Causes – are true. The Stoic approach strikes me as attractive, both because it looks at humans together with animals and other parts of the world and because of its upshot for human agency. Our reasoning, including our decision-making, constitutes some of the causes that co-cause the world’s overall movements. What remains puzzling, however, is that our reasoning is subject to norms. Ultimately, I argue, the puzzle is how norms for practical reasoning fit into the physical world. This reconstruction does justice to the evidence. It recognizes that the Stoics address human movement in the context of a scala naturae. And it predicts what indeed we find: a wide range of texts about the status of human assent, indicative of the awareness that this is not an easy topic.

This article shows how two basic meanings of psukhē – namely ‘breath’ and ‘life’– may have helped Platonising or for that matter Stoicising doxographers to lend to various pre-Platonic philosophers the view that the world is ‘ensouled’. I do not try to systematically reconstruct how these cosmo-philosophers conceived the relationship between the world and what was to become ‘the soul’. I do suggest, however, that framing the problem in terms of ‘breath’ and ‘life’ helps us in getting a more adequate understanding both of the authentic evidence and of the history of its reception. Indeed, to the extent that it is possible, I try to reconstruct the interpretive steps that led, with various degrees of legitimacy, from the original wording to its Platonising or Stoicising deformations, which remain all too often the framework of analysis in modern interpretations. Five case studies are considered: Thales, Anaximenes, Heraclitus, some Pythagoreans and Alcmeon.

This chapter does not directly address the issue of the relations between biology and cosmology as such, although it refers in passing to Galen’s deployment of the microcosm/macroscosm model for the understanding of the nature of the human form and its relation to, indeed its mirroring of, the overall structure of the universe. But it does deal with how and why Galen thought that a proper understanding of the enormous complexity, goal-directedness, economy of animal and pre-eminently human structures demands explanation in terms of a providential, artistic and indeed aesthetically motived designer-god. That is, a proper understanding of the biosphere, and in particular of human physiology, demands a commitment to, and an understanding of, what Galen takes to be a fundamental cosmological fact, namely that the universe is indeed providentially ordered. The bulk of this chapter is devoted to teasing out in detail the nature and working-out of these fundamental commitments.

Plato’s cosmology in the Timaeus can be seen as being framed in biological terms, since it claims the universe as a whole to be a living being, more specifically, a created god. In this chapter, I show that the central assumption that leads Plato to understand the created cosmos as a living being is the idea that the world is as good as possible. In a second step, I want to show that this assumption of the world’s bestness is also responsible for two important twists to the biological framing Plato uses. First, being as good as possible also implies that the world is self-sufficient, which means that many of our common biological notions are of no relevance for an account of the cosmos as a living being. Secondly, I show that while Plato gives an account of all kinds of living beings, his assumption of the bestness of the world leads him to be ultimately interested only in rational living beings. Accordingly, what starts out in biological terms turns into a form of rational psychology and rational theology. This will finally lead to a discussion whether Plato works with a consistent notion of life in the Timaeus.

The theory of recapitulation is best known in its evolutionary form, as it was this form that Ernst Haeckel captured with his famous biogenetisches Grundgesetz (‘ontogeny is nothing other than a succinct recapitulation of phylogeny’). It is a theory that is justifiably associated above all with the natural philosophy of the eighteenth to twentieth centuries. Yet some historians of science have raised questions about its roots in ancient thought, and this chapter aims to explore a selection of natural philosophers in antiquity (especially Empedocles, Aristotle, Plato and Plotinus) in order to determine how close they came to recapitulation theory. Certain Presocratic thinkers appear to have anticipated recapitulation theory in some evolutionary sense, but it is no longer to be found in Aristotle and the Platonic tradition. This is not simply because Aristotle and Plato rejected evolution, since there are also non-evolutionary versions of recapitulation which are founded upon hierarchical theories of transcendental morphology. It is shown that only the Neoplatonists can be credited with a clear commitment to transcendental morphology but that even they develop their transcendental morphology in a way that does not lend itself to recapitulation theory.

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 Platonic cosmogony and zoogony of the Timaeus is distinctive in that the actions of the Demiurge and the lesser gods are modelled on a wide variety of skills, some obeying mathematical principles, some being modelled on more empirical crafts. Focused on Tim. 30c-34a, this chapter examines the reasons provided by Timaeus to account for some key properties attributed to the body of the World Animal (uniqueness, completeness, composition out of four elements, sphericity) and considers in detail Timaeus’ arguments to account for the actual composition of the World Body out of four elements unified by the mathematical bond of analogia. It is suggested that these arguments belong to a broader Platonic reflection on how to bind multiple parts into unified and coherent wholes. This broader Platonic reflection is here labelled ‘desmology’, a word coined on the Greek noun desmos (bond) frequently used in the Timaeus to refer to cosmogonical and zoogonical processes. This chapter also argues that making sense of how Plato uses desmos and other cognate terms in the Timaeus is key to understanding to what extent the cosmo-zoogony of the Timaeus as a whole actually fulfills Socrates’ strong teleological requirement for natural science expressed in the Phaedo (99b-c), as he criticizes earlier Presocratic accounts.

This chapter explores Aristotle’s criticism of the Platonic idea of a cosmic soul as a first principle of motion, in the theory of animal voluntary motion that heoffers in theDe Motu Animalium. According to Aristotle, animal self-motion and the movement of the heavens are alike in that they both depend on an unmoved mover. But it is not immediately clear how this comparison works in detail, since for Aristotle the unmoved mover in animal motion is not directly an external object of desire but the animal’s thinking about an object of desire. Hence, there must, for Aristotle, be some parallel thinking involved in the movement of celestial bodies. Such an account, however, is missing from the De Motu Animalium. To find one, we need to consider the metaphysical cosmology set forth in Lambda, chapters 6–10 of Metaphysics, which posits a soul for each of the moved heavenly bodies, a soul which thinks of the sole absolutely unmoved mover of the universe, indesiring it through a form of rational desire. Thus Aristotle departs sharply from both Plato in the Timaeus and the subsequent Platonic, Stoic and Neoplatonic traditions, according to which celestial motion is not be explained by individual souls in each of the moved celestial bodies but by a single soul of the cosmos as a whole , located at the outermost sphere of the cosmos.

Emphasis on the ‘craftsmanlike’ character of creation in the Timaeus can give the impression that the cosmos is no more an ‘animal’ than Dr Frankenstein’s monster. But Middle Platonists took more seriously the biological implications of the claim that the god is the world’s father as well as its maker, implanting a soul in matter which (as in all animals) brings the cosmos to maturity through its own creative agency. Entailments of the view are that the world soul is first and foremost the ‘nutritive’ soul of the cosmos and that the soul must be a structural feature of the cosmic body rather than a distinct substance.

This chapter offers an account of the state of Roman law and Hellenistic philosophy at the beginning of the period of interaction, for which the Roman embassy of the Athenian philosophers in 155 BCE offers a convenient starting point. In the 2nd century BCE the inegalitarian and expert-guided manner of dispute resolution in Rome is secularised, with case law becoming its main product. In philosophy the most important schools that attract the attention of the Romans are the dogmatic Stoics and their sceptical adversaries, the Academics.