Chapter Five was devoted to the metaphysics that underpins the Stoic theories of everlasting recurrence. The present chapter focusses on three of these theories in some detail. At least two of them, as I explain in section 6, are early Stoic. As we shall see, one is stronger than the other two, and the two weaker theories are revisions of it. A central component of this chapter is the thesis of Identity, according to which there must be a full type-identity between the events of any two cosmic cycles. Why should this thesis be true? Why could not the events be slightly, or even completely, different? Thus, sections 1 and 2 describe the three theories and how exactly they differ from one another. In sections 3 and 4 are devoted to the argument for Identity. The argument is based on the nature of the Stoic god. It is his full rationality that requires that the token-events of each new cosmos be fully type identical to those of the previous one. I close the chapter in Sections 5-6 with a discussion of the two weaker theories. What are their philosophical motivations? And in what order did they emerge in the history of Stoicism?

By way of conclusion, this chapter deals with two issues that are deeply connected to the argument of the book but that I shall leave open. The first one is Chrysippus’ own answer to question of why the Stoic god would want the conflagration if the new cosmos is identical to the old one and no improvement is possible. The second issue is when the Stoic god designs the cosmos if the series of cosmic cycle is beginningless and changeless. This second issue is related to the larger topic of cosmic creation and the link between the Stoic and the Christian god. Thus, it is of more general interest and may help to put the argument of the book in a wider historical perspective.

The chapter studies this mechanism in detail and focusses on the following questions. First, what are these ‘exhalations’ (ἀναθυμιάσεις) and why do they rise up in the sky? Secondly, why does the desiccation of the sublunary region cause celestial fire to descend to this region? More particularly, why does not celestial fire consume the sublunary region before it totally dries out, as an ordinary wildfire would consume a forest that is still relatively green and full of life? Thirdly, how does celestial fire consume the exhalations and the substances that it finds in the sublunary region? And, more generally, how do the Stoics conceive of the physical process by which a mass of fire consumes another body? In other words, how do they envision the phenomenon of combustion? Fourthly, what is the place of the concept of combustion in their elemental theory? And, finally, how long does the conflagration last?

The early Stoic cosmos is sharply different from that of Plato and Aristotle. But it is also unique compared to that of the Presocratics. In this chapter, I seek to prove that this is so by concentrating upon the Stoic theory of conflagration we just examined. The issue requires an in-depth discussion because Stoic cosmology owes enormously to the Presocratics, and the theory of conflagration is clearly the part of Stoic cosmology that has deeper roots in these early thinkers, much more so than the theories of cosmogony and everlasting recurrence

The conflagration is followed by a cosmony that restores the cosmos. In fact, a permanent end would be impossible given the rationality of the early Stoic god. In this chapter, I limit myself to asking what is the structure of the cosmogony. How, exactly, is the large mass of fire left by the conflagration transformed in the cosmogony into the differentiated masses of air, fire, water and earth that constitute the present cosmos? I shall argue that the cosmogony, which sets off as soon as the conflagration is over, divides into at least three basic stages: (a) the formation of the four elements and of the sublunary and supralunary regions as two differentiated parts of the cosmos, (b) the formation of composite homogeneous substances (gold, flesh, wood, etc.) out of the four elements; and (c) the formation of composite heterogeneous substances (animals and plants) out of homogeneous ones.

This chapter and the next build upon the previous chapters by addressing a vital question that they leave open. What is the relation between the cosmos issued from the cosmogony and the cosmos previously destroyed at the conflagration? Is it the same cosmos? Or is it different? The issue of identity drove a great deal of dispute within the school. In fact, as I explain in Chapter Six, there were three clearly different Stoic theories of everlasting recurrence that opposed one another on this question. In the present chapter, I concentrate upon two broader and more basic metaphysical problems presupposed in the dispute over identity. The two problems, concisely put, are the following. (a) Why is the present cosmos present as opposed to past or future? In general, how is the present distinct from the past and the future? (b) Supposing that the present cosmos is type-identical to the previous one and the next how can they really occupy different places in time? And how can the times themselves be distinct if the events are type-identical?

In this introduction, I start with a brief description of the structure of the Stoic cosmos that explains how it differs from other cosmic systems in Antiquity. I then describe the main goal of the book and some of the general methodological principles that I follow. Finally, I offer a synopsis of the argument that unifies it.

This chapter brings together the theory of conflagration and the theories of everlasting recurrence that embrace Identity, and draws a paradox from their combination: the ‘paradox of destruction and restoration’. If the new cosmos is wholly type-identical to the old one, would it not be more rational for the Stoic god not to destroy the latter in the first place? The idea of a conflagration followed by the restoration of a type-identical cosmos seems to threaten the rationality of the Stoic god. In this chapter, I explain how, on my view, the Stoic god is immune to this objection.

To present some of the basic notions that will be used throughout the book, this chapter offers an analysis of the Stoic cosmos that complements the brief description given in the Introduction. I start by looking at its internal structure and composition, the distinction between the sublunary and the supralunary regions, the way in which they interact with each other, and the distribution of the four elements in the sublunary region and their reciprocal change. Subsequently, I discuss the place of god in the cosmos and, in particular, the pantheistic idea that god is one of the two basic cosmic principles as well as the thesis that the cosmos is a living being whose ‘seminal reason’ (σπερματικὸς λόγος) is god. Finally, I present ‘theological determinism’, the deterministic conception of the cosmos that the early Stoics advocate and that is prevalent in their theory of everlasting recurrence.

Vitruvius’ De architectura (c. 35–23 BCE) offers an ideal lens through which to view the emergence of the Imperial artes. In the introduction to his work, Vitruvius develops an elaborate theory of architectural knowledge that connects the discipline with other branches of specialized knowledge and gives pride of place to causal explanations of architectural method via natural first principles. Vitruvius’ theory is tailored to architecture but is of wider importance in that it establishes a general notion of ars predicated on the scientific premises sketched in Chapter 2. True to his expansive conception of the discipline, throughout his treatise Vitruvius carefully explains his methods in terms of natural first principles, demonstrating their fundamental soundness. His advice for orienting city streets and walls (Book I) and for choosing building materials (Book II) exemplifies his characteristic interest in connecting architecture with a broader understanding of nature.

The first and most important step into the Peripatetic study of living beings is the observation that life takes many forms. In the sublunary world, it takes the form of plant and animal life (with human life as a special kind of animal life). When Aristotle and Theophrastus speak of animals and plants, they never assume that they are a single form of life. This is confirmed by what we read at the outset of the Meteorology, where Aristotle outlines an ambitious research program that ends with separate yet coordinated studies of “animals and plants.” Whether there is unity, and how much unity there is, in these two studies remains an open question at the outset of the Meteorology. But when we look at the two corpora of writings that Aristotle and Theophrastus have left on the topic of animals and plants, we see that the unity they are able secure is limited. Last but not least, this chapter shows that the study of the nutritive soul advanced in Aristotle’s De anima cannot secure unity within the study of animals and plants.

This chapter presents a new, annotated translation of the philosophical treatise Peri kosmou (often known by the Latin title De mundo), written in approximately the 1st century AD (a much-disputed date) and preserved among the works of Aristotle. The chapter introduction emphasizes the literary polish of the work, and the remarkable way in which it draws accurately upon a late hellenistic understanding of geography, the earth sciences, and cosmology in order to sustain its open-minded, but fundamentally Aristotelian and anti-Stoic, theological position and stimulate readers to immerse themselves more deeply in its philosophy.

This chapter presents new, annotated translations of the testimonia and fragments of Timosthenes of Rhodes (active 282–246 BC), arranged as 37 extracts. An appendix contains a new translation of Aristotle’s discussion of the winds at Meteorologika, 2. 6. The chapter introduction addresses the difficulty of linking references to Timosthenes to the various book titles of which we have reports, but argues that we should not automatically divorce him from the Timosthenes who wrote about the Pythian Melody of Delphi. His distinctive contribution to geography was in assembling detailed navigational data, particularly specific local topography useful to ship-captains. Typically of literary writers, however, he enlivened his technical material with information about local cultures. His legacy was considerable, probably visible, for example, in the Roman-period Stadiasmos (Chapter 31 of this volume).