It has long been recognized that astronomy was a catalyst of the Scientific Revolution, spurring on deeply consequential speculation about the nature of the cosmos and its physical principles. Yet the history of celestial physics is far richer than was thought a generation ago, and there is much to be learned about the origins of the field, particularly in the sixteenth century, when humanist activity brought forth a dazzling array of philosophical possibility—from reconsiderations of Aristotle and Islamicate commentary to the revival of Platonic, Epicurean, and Stoic worldviews. Celestial physics offered some of the most heated arguments for or against the Aristotelian cosmos, with controversial attempts to account for astronomical observation by integrating various causal innovations. This chapter will focus on a number of themes that mark celestial physics and cosmological speculation in the sixteenth and early seventeenth centuries: the order of the celestial bodies and their nature, the relationship between celestial and terrestrial things, the question of celestial animism or vitalism, and the status of the divine in celestial nature.

In this chapter the reader is introduced to the background to Roman Egypt, starting with Egypt’s experience of foreign rule under the Kushites, Assyrians, Persians, and Greeks. The impact of the three centuries of rule by the dynasty of the Ptolemies, who took over after the death of Alexander the Great, is explored; many traditional Egyptian institutions remained in place, most importantly the great temples. Many Persian administrative innovations were also kept, but the Greeks brought in their own financial practices. Substantial immigration from the Greek world and the Levant changed the population, and Greek largely displaced Egyptian as a language of power, even though Egyptian society was substantially multilingual. Periodic revolts show that foreign rule was not universally accepted, but many Egyptians became part of the Ptolemaic administration and served its economic goals, which depended heavily on exporting wheat. Romans began to settle in Alexandria in the last decades before the Roman conquest.

In 1632, the Italian astronomer Galileo Galilei (1564-642) was placed on trial by the Roman Inquisition for daring to claim that the Earth moved. Since then, many people have interpreted this encounter as a battle between science and religion. The story of how Galileo arrived in front of the Inquisition, however, is both more complicated and more interesting than one of simple conflict. When Nicolaus Copernicus (1473-543) suggested that the Earth moved around the Sun in his De revolutionibus of 1543, he launched a debate about more than the structure of the universe. His work called into question the legitimacy of traditional beliefs, and ultimately led Galileo to argue that he, not the theologians of the Catholic Church, had the right to study and interpret the natural world. It was a far more radical position than those taken by other astronomers, like Tycho Brahe (1546-601) and Johannes Kepler (1571-630), who proposed models of the cosmos inspired by religious faith. More than anything, Galileo’s story centers around a single question: Who should have the authority to proclaim the nature of reality?

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.

After introducing Porphyry’s commentary, this chapter asks how Porphyry saw himself at the time of writing. Was it as a ‘Neoplatonist’ and pupil of Plotinus as usually presumed? Does he write as a mathematician and scientist or as a philosopher? Assuming he sees harmonics as a natural interest of the philosopher, what sort of philosopher does he represent himself as? He could claim to be embarking upon a ‘Pythagorean’ task rather than a ‘Platonist’ one, though the two were hard to distinguish in this era. Either would involve the Timaeus. His persona may have a bearing on the work’s date. The long discussion on logos and sensation is examined for indications of Porphyry’s sources and allegiance. This epistemology is distinctive, and the most distinctive features are independent of Plotinus. The section’s eclecticism and polymathy make it hard to associate with a single school, like Thrasyllus, Porphyry’s only named authority here. Porphyry’s persona is in fact complex, as much Pythagorean as Platonist, with an early dating feasible, allowing for debts to Longinus and to the mathematician Demetrius rather than to Plotinus. A Pythagorean’s interest in harmonics is natural.

The eighth chapter focuses on the thought of Jurjānī to understand later developments in the occasionalist tradition. Jurjānī was one of the most important Ashʿarite theologians who transformed occasionalism from a theory of causality into the central axis of all theological thinking. The notion of possibility made central by Ashʿarite occasionalism became the modus operandi for thinking about questions from prophetology and eschatology to theodicy and free will. More importantly, Jurjānī develops a critical philosophy of science to appropriate and criticize Aristotelian-Ptolemaic-Avicennian natural philosophy/sciences. An examination of this attempt reveals the complex relationship of Ashʿarite occasionalism with medieval natural philosophy and sciences.

Chapter 3 gives an account of the transmission of Islamicate meteorology into Northern and Western Europe. An early phase was the collection and study of the texts known as the Alchandrean Corpus, which provided short introductions to topics within astronomy and mathematics. The chapter then considers twelfth-century translations of more advanced works, and especially of treatises on weather-forecasting. The contributions of Petrus Alfonsi, and the reception of Latin translations of Arabic versions of the works of Ptolemy, are discussed. The chapter argues that it was this period that saw the creation of Latin, Christian forms of astrologically based weather forecasting. Moreover, this was no transitory fashion, and the new, astrometeorology remained dominant until the seventeenth century. Central to this new science was the application of fundamental works by Ptolemy, and this is considered in detail. The final part of the chapter gives an outline of the works of Islamicate astrometeorology that were translated into Latin, and especially of the theories of al-Kindi. The conclusion is that Latin writers and translators searched out works on weather forecasting, and rapidly began to produce their own versions.

This chapter looks at Greek and Roman approaches to climate and weather, showing how geographers, astronomers, and physicians organised and understood geographical differences, and the consequences of those differences for agriculture, navigation, and even human physiology and disease. In some sources, very broad generalisations were made based on latitude alone, and in others variation was handled on a much more local basis. Long-term prediction of local weather was seen as an important task and utilised methods from astronomy, astrology, and folklore alike.

Over the past decade, anthropogenic climate change has encouraged authors and readers to confront new modes of imagining time, selfhood, and narrative and to reassess the relationships among experiential, historical, and climatological time. In Western literary culture, historical and climatological time traditionally have seemed one and the same. Working within the 5000-year time frame of biblical history, writers envisioned a world that, since the sixth day of creation, always has been inhabited and therefore always had been shaped and reshaped by humans. In this worldview, ‘nature’ is always a product of anthropogenic intervention. Beginning around 1800, however, work in geology, planetary astronomy, and palaeontology transformed conceptions of climate by decoupling planetary history from human experience, memory, and myth. In giving narrative form to the collision of experiential and climatological time, Anthropocene fiction explores the problem that science fiction often seems more ‘realistic’ than traditional narrative realism.