Rousseau's case has some interesting parallels with that of another French philosopher with a strong affinity for Plato: Alain Badiou. Badiou has a weighty theory of political change derived from a formidably rigorous set-theoretical ontology. A self-confessed Wagnerite, he has also penned a few dilettantish forays into musical aesthetics, the most substantial of which is a book-length defence of the founder of Bayreuth (Five Lessons on Wagner, translated by Susan Spitzer (New York: Verso, 2010)). Badiou's musical knowledge bears no comparison with Rousseau's. None the less, what unites these two giants of political philosophy is a suspicion that their thinking about music somehow shapes or even drives their conception of political categories. Badiou does not only think the political through the lens of musical examples, but, moreover, attributes to Wagner in particular a bringing-together of ontology and phenomenology which, by his own admission, he has yet to accomplish fully in his philosophical thinking. There is something to be gained, in other words, from thinking musically about the political. Julia Simon makes a similar and highly persuasive case for Rousseau, arguing that his lifelong engagement with music conditioned his thinking in a number of areas stretching beyond the horizon of aesthetics and, furthermore, that looking at his work on music can shed new light on the familiar foundational concepts of his social and political thought, such as the general will, democracy and the relations between individual and community.

The strength of this ambitious book is that it does not simply situate Rousseau's music-theoretical writings alongside his social and political philosophy. Rather, it seems that Simon aspires to an altogether more provocative claim: that Rousseau's music theory and aesthetics itself constitutes a mode of thinking about the political. In articulating this rapprochement between Rousseau's musical and political thought Simon offers a welcome rejoinder both to the relegation of his musical writings to a mere footnote among philosophical scholarship, and also to the corresponding tendency in music studies to view these writings solely within the context of contemporaneous musical debates or the history of musical aesthetics, separate from his highly influential political conceptions of community. The idea that music might embody social relations is, of course, far from new for a discipline so steeped in Adorno that it keeps rediscovering its saturation point anew. But Adorno himself did most of the work towards joining the dots, connecting an analysis of form and style to a Marxist critique of social relations via a theory of subject–object relations. Rousseau, by contrast, is scarcely concerned with bringing the two dimensions into dialogue, except perhaps in so far as he thinks about the role of music in society. This overdue task falls instead to a versatile scholar like Simon, who is able to flesh out a context in which a dialogue between music and politics comes to the fore.

This book is more than an invitation to think broadly and across disciplinary divides, although it is also that. If, as Simon contends, Rousseau thinks the political musically, then a close examination of the musical texts does not merely reveal an analogical connection, but, on that basis, promises to revise or even overturn philosophical interpretations of Rousseau. In a bold opening salvo Simon mobilizes various reflections on music against Jacques Derrida's deconstruction of Rousseau in De la grammatologie (Paris: Les Éditions de Minuit, 1967; translated by Gayatri Chakravorty Spivak as Of Grammatology (Baltimore, Johns Hopkins University Press, 1976)). Here both the strengths and shortcomings of Simon's approach come into focus. Simon argues that Rousseau's strong commitment to musical performance over the written score should not be confused for the privileging of speech over writing that Derrida finds in Rousseau's ideas about language. Rousseau's preference for live musical performance should not, she claims, be read as a metaphysics of presence. The reasons Simon offers for this merit careful consideration because they get at the interface constructed between musical and political-philosophical thought upon which her enterprise hinges. Ultimately, Simon argues that Rousseau privileges a certain kind of presence, but one that is unstable, ephemeral and marked by potentiality rather than metaphysical self-identity. It is hard to imagine that Derrida would have been persuaded by this counter-argument. There is, I think, an argument to be made here about the deconstructive potential of the temporality of musical listening, conceived in all its complexity, torn between ephemeral sounding and the activity of mental representation, but this is not something that Simon explores in any meaningful way.

At one point Simon appears to claim that, at least within the eighteenth-century context, before the advent of mediating recording technologies, music is simply resistant to deconstruction: caught in a neat binary opposition between performance and score, music somehow lies outside of the Derridean logic of supplementarity. Just before this, however, Simon has allowed a certain credence to Derrida's critique by attempting to ward it off: music in Rousseau's conception does not succumb to a critique of presence because its ‘sequential nature resides in a temporal economy that is both present and absent’ (12). On the one hand, music's rigorous division between performance and text leaves no scope for deconstruction, none of the loose threads by which Derrida might customarily unravel phonocentrism. On the other hand, music as live performance already deconstructs itself on account of its temporality. If this idea that Rousseau's music theory rebuts deconstructive readings of his thought were to be rigorously pursued, one can imagine focusing on the seeming contradiction whereby music-as-performance is at once before and after – always out of joint with – deconstruction: both not-yet and always already deconstructed, musical performance thus conceived refuses to be apportioned between presence and absence. As it stands, though, Simon's analysis feels somewhat under-theorized; as with other philosophical confrontations staged throughout the book, especially in the discussion of Kant in chapter 5, there is a danger of insufficient attention to detail when arguing against the grain to withstand the critical power she aspires to challenge.

Temporality again motivates the argument in chapter 1, where Simon revisits the theme of individual and community via the common experience of time in musical listening. The argument risks overreaching itself when she goes so far as to claim that the shared emotional response to music constitutes the general will, an assertion she subsequently backs away from to some extent. This is undoubtedly an inspired reading, which attributes considerable potency to the theory of musical listening developed in Rousseau's writings and to the political potential of listening more widely, a theme which resonates with a thread of philosophical thought running from Martin Heidegger through Derrida to Jean-Luc Nancy. When the stakes are so high, however, the interdisciplinary method reveals both its explanatory power and its weaknesses: this reader yearned both for a more critical discussion of Rousseau's collective voluntarism and also for a more rigorous analysis of his theory of musical listening, bolstered by close engagement with recent philosophical work on Rousseau and a greater familiarity with the ways in which musicology has begun to approach performing and listening in recent years. Simon is neither a musicologist nor a philosopher, but a scholar of eighteenth-century French literature and culture, moulded by the rise of theory in the American academy. As such, she is well positioned and one of very few scholars able to take on this ambitious interdisciplinary endeavour and bring together the two strands. And yet the rewards of such an approach are matched by the risk of disappointing specialists in either field. Simon's thoughts on temporality, for example, wander in various directions over the course of the book; both music theorists and philosophers, preoccupied in different ways with such questions, might wish for a command of both disciplines able to identify clearly and confront head-on the issues in common. Notwithstanding these reservations, Simon opens up a valuable space in which to develop a coherent account of how the temporal becomes the decisive link between the musical and the political.

Later in the book, in chapter 3, it is musical tuning which provides a model for democracy. At other times, it is Rousseau's concerns about communicability that link his musical aesthetics to social and political concerns. This raises an interesting question for music scholars: if Rousseau thinks the political musically and hence music is deemed to be capable of ‘thinking’ politically, at what level and by what means does music become a vehicle for political thought? Simon seems to suggest that music is capable of manifesting what are essentially social relations in a number of different dimensions: within pitch structures, in listening practices, as a form of moral pedagogy and so forth. In this way, Simon's ambitious and often provocative book lays down the gauntlet for future scholarship to examine in closer detail how music offers new ways to conceive of social relations not simply in the (ab)uses to which it is put, but far more subtly in its sounding materiality, and in the relations it creates with and among listeners in live performance.