This book is the first in a new series devoted to Critical Conjunctures in Music and Sound, one of the series’ aims being to question the relationship of music studies with other forms of knowledge production. Andrew Hicks's monograph constitutes a splendid start to the series as he introduces it with the strong claim that (musical) sound has always been an integral part of the history of studying the cosmos, the hope being to attract a wide readership from diverse fields, including sound studies, music studies, medieval studies and also the history of science. This interdisciplinary work overturns the commonly held belief that music theory was essentially absent from the ‘twelfth-century Renaissance’ that is familiar to intellectual historians and historians of science.

As part of rewriting this chapter of medieval history, Hicks has synthesized material from domains usually treated separately (e.g. music theory, philosophy, cosmology) in order to create a new history of the fundamental role of harmony in twelfth-century cosmological discourse. Specifically, he has looked at the reception and development of ancient Platonism by twelfth-century philosophers such as Bernard of Chartres and William of Conches, who engaged in dialogue with a core set of texts mostly dating from the late fifth and early sixth centuries. These include Plato's Timaeus, Macrobius’ Commentary on the Dream of Scipio, and Boethius’ Fundamentals of Music. Modern scholars have studied these sources and their fortunes independently from each other, rather than looking at them together over a given period. The synchronic approach favoured by Hicks reveals music theory's ‘foundational and often normative role within the development of medieval cosmological models’ (p. 5).

The book is in two main parts: the first two chapters offer a ‘Framework’, the second three chapters deal with ‘Particulars’, but to finish there are also a couple of appendices containing material from two highly relevant but little-known Latin sources that Hicks has edited. (For those whose Latin is rusty or non-existent there is a website from which it is possible to download English translations.) Whereas most texts dealing with cosmic harmony look to Pythagoras first, the opening chapter does not start with the mathematics of music, but instead begins with physics, demonstrating the idea of nature ‘as a carefully ordered and harmonized set of principles governing the created world’ (p. 32). Chapter 2 maps out the divisions of philosophy that supported this idea, an exercise that reveals how Boethius’ influential scheme making music a branch of theoretical mathematics (the quadrivium) further divided into musica mundana, humana and instrumentalis was not found in one place but was rather a synthesis based on several texts. In fact there were other divisions in circulation to which twelfth-century readers had access, allowing for the creation of new taxonomies, as shown, for example, in the fourfold division of philosophy by Hugo of St Victor (c.1120).

Moving into the second part of the book, Hicks has organized its three chapters to deal successively with the harmonies of the microcosm, particularly focusing on the soul being or having a harmony; with the materiality of the voice and hearing and the nature of sound; and with the harmony of the spheres. This chapter in particular demonstrates Hicks's mission to show that, far from being the final end of musical speculation, the planetary strains ‘are a symptom, not a cause, of the broader commitment to a well-composed world’ (p. 191). Moreover, instead of offering a unified and unchanging view, the twelfth-century accounts of cosmic harmony differed strongly from each other and also changed over time, a complexity that is well captured in Hicks's nuanced interpretation of his chosen texts. Here, as in other chapters, there are plentiful occasions where the sources are allowed to ‘speak for themselves’ in the form of extracts presented both in the original Latin (sometimes Greek) and in English translations beneath. The picture that emerges is one where the music of the spheres ultimately falls silent, but this is in dialogue with the Platonic sources that had hitherto grounded its reality rather than with reference to Aristotle's rejection of its existence.

This ambitious book opens a new window onto twelfth-century philosophical thought, and successfully shows how deeply Platonic conceptions of harmony were embedded within it. As well as becoming essential reading for medievalists who want to develop their knowledge of speculative music theory, it is also worth the attention of early modernists and scholars who focus on present-day philosophical and scientific thought. For while it enriches our understanding of twelfth-century philosophy, it also raises the question of what happens to the doctrine of the harmony of the spheres in later centuries. For example, we find Marsilio Ficino in the late fifteenth century believing cosmic harmony to be real, his goal being to make this Pythagorean music come alive again. With reference to Kepler in the seventeenth century, and to Gilles Deleuze in the twentieth, Hicks points to the enduring legacy of cosmic music, ‘which has continually changed its tune to harmonize with the prevailing musical aesthetics of its aspirational auditors’ (p. 253). As it says on the cover, his book encourages us to rethink the role of music and sound within our greater understanding of the universe.