It's a confusing time to study Enlightenment musical culture. In addition to the common fear that institutional and popular support for what we do is on the wane, the humanities in general have also recently witnessed a dizzying proliferation of new intellectual trends: there is the digital turn, of course (prompting questions about its connection to Enlightenment projects of knowledge compilation and taxonomy), but also the affective turn, the global turn, the postcritical turn and, indeed, even a posthuman turn. With this maddening choreography of constant revolution, have the humanities finally spun out of control, becoming ‘post-’ themselves?

Not quite. The advent of posthumanism isn't a signal that the humanities are over or have collapsed, but rather that they will have to evolve as human and machine life become ever more closely entwined. Advances in biomedical technology and machine learning make it increasingly difficult to tell where the human ends and its prostheses begin, so the humanities will have to refine for themselves their own understandings of what it means to be human. In addition to acknowledging this contemporary situation, posthumanism also provides a critical method that seeks to decentre radically the place of the human in the world, preferring to interpret human life as one node in a vital network of technologies, animals, ecosystems and natural forces. In the words of the prominent posthumanist Pramod K. Nayar, critical posthumanism demonstrates ‘how the human is always already evolving with, constituted by and constitutive of multiple forms of life and machines’ (Posthumanism (Cambridge: Polity, 2014), 11). Our instruments fashion us as we fashion them, and we learn to be who we are because of them.

This insight will be familiar to many scholars of eighteenth-century music. We understand that musical style transformed as instrument design evolved during the course of the century; information constantly moved back and forth between inanimate instruments, the people who made them and the creative work that others did with them. Emily I. Dolan chronicles this story brilliantly in The Orchestral Revolution (Cambridge: Cambridge University Press, 2013), demonstrating how instruments helped to shape the aesthetics of timbre and form. And readers of period thinkers like Johann Joachim Quantz, for instance, will know that the quality of a flute player's music is dependent as much on the material from which the flute is made as it is on the work of the performer's fingers or lips. So even if it hasn't gone by this name, posthumanism is already at home in eighteenth-century music studies.

Unfortunately, this isn't where the confusions end. Taken to its furthest logical extensions, posthumanism entails a thorough critique of Enlightenment humanism and the cultural products that represent it. Indeed, it is a trope of posthumanist scholarship to call up Enlightenment culture in order quickly to dismiss it, arguing that the eighteenth century amplified and consolidated the humanism it had inherited from the Renaissance. Enlightenment thought, in much of this scholarship, is identified with the belief in a rational, autonomous human subject fully in control of its environment. Worse, this era is said to be responsible for our own faulty, inflated notion of the human and the broad culture of anthropocentrism that has propped it up since then. According to this more extreme view, Enlightenment musical culture would seem to have helped construct the kind of worldview from which posthumanism seeks urgently to escape.

It's this confusion that I hope to address here, demonstrating how the musical cultures of the Enlightenment can and often do show us a decentred picture of humanity. Eighteenth-century music tells us a story of how ‘we have always been posthuman’, in the words of N. Katherine Hayles (in How We Became Posthuman (Chicago: University of Chicago Press, 1999), 291), much in the same way that Bruno Latour suggests in his influential monograph that We Have Never Been Modern (trans. Catherine Porter (Cambridge, MA: Harvard University Press, 1993)). To find anthropocentrism in the Enlightenment's aesthetic cultures, then, is really only one narrow way of reading and understanding its artefacts. I hope to offer some others.

To start, it's important to recognize the scholarship that has already begun this work even while not in explicit dialogue with posthumanist critiques of the Enlightenment. In countless publications, Arthur W. J. G. Ord-Hume has chronicled the early history of mechanically produced music, highlighting the importance of eighteenth-century automated instruments for our understanding of performance practice (see in particular ‘Ornamentation in Mechanical Music’, Early Music 11/2 (1983), 185–193). The tunes that Handel set for mechanical organs and musical clocks, for example, differ significantly from their notated originals. Ord-Hume recounts how audiences of Handel's machine music were shocked and surprisingly moved by the delicacy and effectiveness of the mechanical instruments, which would seem to have captured the performing nuances of human musicians. What's more, Handel's automated organs and clocks were not limited to original or arranged instrumental music – they also played versions of his opera arias. There was something of a sensitive voice in these machines.

Consider also the work of Jessica Riskin, whose recent book The Restless Clock (Chicago: University of Chicago Press, 2016) locates the origin of artificial life in Jacques de Vaucanson's musical androids, which were first displayed in 1738 at the Foire Saint-Germain in Paris. One was a flute player that performed on a real flute using forced wind, an automated embouchure and moving fingers. The other was a piper, also playing a real set of pipes with wind pressure and, additionally, accompanying itself on a drum. Unlike the devices for which Handel wrote music, these were machines that actually performed on instruments the way humans did. They therefore further encouraged their audiences to wonder whether the rational human skill of music-making could be fully automated. In this sense they are pendants to more recent feats of automation, such as the victory of the Deep Blue chess computer over longstanding champion Garry Kasparov in 1997.

Another way that musicology has narrated this history is through the phenomenon we now call the Affektenlehre: an unstable consensus among theorists that certain manipulations of music's formal parameters could evoke specific affects in the listener. When Johann Mattheson tried his hand at a speculative taxonomy of musical affects in Der vollkommene Capellmeister (Hamburg: Christian Herold, 1739), it was in the context of a chapter entitled ‘On Sound in Itself, and the Natural Theory of Music’ (‘Vom Klange an sich selbst, und von der musicalischen Natur-Lehre’). In this chapter Mattheson is most concerned with the efficacy of musical tones, here conceptualized as the material reality of their sound vibrations. Mattheson wonders how it is that sound has automatic, physiological effects on the human body. He builds explicitly on Descartes, who in turn had theorized the affects as the ‘motions of the animal spirits’ within us. Although it is true that no coherent programme of musical affect theory ever emerged from the Affektenlehre, it is also the case that documents like Mattheson's indicate an awareness that human feeling is deeply corporeal and entangled with the effects of the exterior environment.

But it's not just in quirky sideshow machines and the dusty corners of historical music theory that we can discover alternatives to anthropocentrism. They are also to be found in musical works that have, until now, been tightly identified with Enlightenment rationality and that have come to epitomize the classical style. There are many posthuman classics, but I'll briefly discuss three.

Consider Mozart's Magic Flute, an opera set in no specific place at no specific time concerned mostly with the agency of non-human and semi-human actors. When Tamino first meets Papageno, early in Act 1, he enquires about who – really, what – the latter is. Papageno responds: ‘Who I am? Stupid question! A man like you!’. He protests a bit too much. As Carolyn Abbate has demonstrated in In Search of Opera (Princeton: Princeton University Press, 2001), Papageno can and has been read as a man–bird hybrid, a not quite human character with endless corporeal desires to be satisfied. In this way he sets into contrast our protagonist Tamino – a human prince – who takes very little action of his own accord in the drama and mostly has things done for or to him.

The entire plot of The Magic Flute revolves around three inanimate but profoundly agentive instruments. The first two of these are magical: Tamino's magic flute and Papageno's magic bells. The third instrument is Papageno's set of pipes, which are something of a prosthetic extension of his quasi-avian nature. Papageno's possession of this instrument draws his bird-like character closer to the figure of the flute-playing automaton, comingling human, animal and machine. In two parallel scenes that bring the action of Act 1 to a close, these three inanimate instruments take centre stage. First we hear the magic flute, which Tamino plays and which then subsequently charms the animals of the forest. Tamino next uses the magic flute as something like a bird call in order to find Papageno. He is answered by Papageno's pipes: ‘Ah! That is Papageno's tone!’. The pipes, which are not magical, effect the first connection between Tamino and Pamina, since each knows the other is present through the traded calls. Then, in a distorted repetition of the animal-taming scene, Papageno uses his magic bells to arrest and manipulate Monostatos and his slaves, saving the day.

With these two scenes, The Magic Flute takes up a question that will occupy it for the remainder of the opera. Are musical tones – in and of themselves – intrinsically powerful? Does opera's aesthetic force derive from them? In one sense, this is the question that all opera has been asking since its inception, obsessed as the tradition is with Orphic myth (another thesis set forth in Abbate's In Search of Opera and also in Gary Tomlinson's Metaphysical Song (Princeton: Princeton University Press, 1999)). But The Magic Flute asks a different version of this question, one that attempts to separate the power of instrumental tones from the power of song. The magic flute and the magic bells are not Orphic singers (neither are Tamino or Papageno). Instead, these instruments are the material placeholders for a disembodied and more abstract force of music itself. In this way, the opera asks a question about music that is not so different from our question about Papageno: human, or partially human?

A similar set of considerations is at play in Haydn's oratorio The Creation. Here is a work that shows us a world without human agency, since for the majority of it there are no humans present. While it's true that Gottfried van Swieten's libretto (published as Die Schoepfung: ein Oratorium; The Creation: an oratorio (Vienna: Joseph Haydn, 1799 and Leipzig: Breitkopf & Härtel, 1803)) describes Adam as the ‘Lord and King of nature all’ (‘ein Mann, und König der Natur’) once he is created, the rest of the oratorio could be read as undermining that sort of offhand anthropocentrism. Most of the cast in this drama are non-human, inanimate and natural characters that team up to create the universe. Haydn and van Swieten partially solve the problem of narration with a host of angels: Raphael, Gabriel, Uriel and the choir of heavenly voices that comment on the action. But the real star of the show is the orchestra, which Haydn expertly deploys in order to depict the agency of natural phenomena.

In the accompanied recitative ‘And God made the firmament’ (‘Und Gott machte das Firmament’) the angel Raphael narrates the second day of creation, when God divides the firmament into above and below. Upon this pronouncement the orchestra rips and rolls in an energetic storm topic, as ‘tempestuous rage’ erupts. Natural and supernatural forces all act as agents in concert. Winds impel clouds, fire inflames the sky, and from the floods come rain, hail and snow, each of which receives its own distinctive treatment in the orchestra.

This closes the second day, and Gabriel leads the choir of angels into a chorus of praise, ‘The marv'lous work behold amazed’ (‘Mit Staunen sieht das Wunderwerk’). The question of the addressee of the choruses of praise in The Creation later became a facet of the work's reception history; it is difficult to know who the angels are exhorting to look on amazed, and some reviewers were confused by this. Certainly it's not God. Perhaps they are exiting the temporality of the creation drama in order to speak to us, in the present day. Another possibility, I think, is that they are singing to nature itself in a musical communication that is shared between supernatural and inanimate characters.

Raphael continues the narration of the third day in his much-remarked-upon aria ‘Rolling in foaming billows’ (‘Rollend in schäumenden Wellen’). Mountains and rocks emerge from the sea in this number, and the geography of the Earth begins to take shape. Midway through the aria we come to a pause. Haydn thins out the texture and slows the pace of events, providing Raphael with a lyrical vocal line that gently droops and ascends. ‘Softly purling glides on through silent vales the limpid brook’ (‘Leise rauschend gleitet fort im stillen Thal der helle Bach’), he sings. The contours of the line suggest the gentle curves of the stream, and the reduced texture and pace allows us to hear the tranquillity of the setting. In a register above all of this, the violins quietly play an active line in triplets – as though in 12/8 – a classic pastoral technique associated with rivers and streams. This surface activity is the moving, rippling water at the top. It's the babbling of the brook.

Moments like this babbling are precisely what The Creation is famous for. Many of them can be said to work something like the literary device of prosopopoeia, in which abstract or inanimate objects are made to act, perform or speak. The brook is only one such expressive character in a drama where we hear the roar of the sea, the footsteps of the sun and praise for the Earth's fabulous clothing. And it is important to remember that not all of this was received with unequivocal celebration. The reception history of The Creation is full of writings that reflect a basic anxiety about musical painting, or imitation in music more generally. According to the nineteenth-century critic Thomas Busby, Haydn ‘attempted imitations of many things inimitable by music . . . [in] the absence of true taste and dignity’ (General History of Music (London: G. & B. Whittaker and Simpkin & Marshall, 1819), two volumes, volume 2, 400). Perhaps the tenor of anxiety in these sorts of writings actually stems less from Haydn's mode of depiction and more from the things he depicted. Prosopopoeia can sometimes come off as silly or merely fantastical (as when the plate runs away with the spoon, for example). But another disquieting facet of prosopopoeia is that it shows us something we know but don't generally like to admit, which is that humans and non-humans can exchange information. Humans are not the only ones who communicate. This could be what provoked some to laugh nervously at The Creation’s musical depictions.

Haydn wasn't alone in letting brooks babble, of course. The comparatively short river scene in The Creation could have been a model for Beethoven's ‘Szene am Bach’, the second movement of his Symphony No. 6, ‘The Pastoral’. Beethoven's river texture is an inversion of Haydn's, with the first violins initially carrying the lyrical melody on top. The murmuring triplets, written out in 12/8 time, are heard below in the second violins, violas and two solo cellos. After four short bars the violin melody broadens in register and the triplets give way to semiquavers, though we still hear tripled subdivisions in the background. This is an altogether larger, perhaps deeper, and louder river. Like Haydn's, this brook is also embedded in an ecosystem. Flutes, oboes and clarinets are featured in the texture over the course of the movement, and at the close they provide for us, respectively, the birdcalls of a nightingale, quail and cuckoo.

One tradition of this symphony's reception history places Beethoven on the edge of the brook. In this vision, what we hear is something like his recording of the soundscape or a transcription of its impression on him. But this seems to be a way of getting around the less comfortable but plausible scenario that the ‘Szene am Bach’ paints a conversation among non-human actors. Beethoven accomplishes this at least in part through the imitation of naturally occurring sounds, giving voice and animation to nature.

Prosopopoeia is the figure that best joins posthuman ideas of distributed information and agency to eighteenth-century aesthetics. In it, we witness performances of and conversations among the natural, the supernatural, the mechanical and the fantastical. Sometimes a human is there, too, participating in the fun, but this human often plays a secondary role to the non-human actors. It is no wonder that the three works discussed here have all had mixed reception histories. These works lavish care and attention onto inanimate objects as though they were people. In so doing, they provide an uncomfortable reminder of the power the inanimate can have over us. And in dramatizing that agency, these works also concern themselves with a question about the agency of musical tones. How do the inanimate vibrations of musical sound hold such power over our human lives? Enlightenment musical culture staged this question again and again, proleptically anticipating the quandaries at the heart of posthuman theory.

Mozart's Magic Flute, Haydn's Creation and Beethoven's ‘Pastoral’ Symphony may once have been employed to shore up narratives about the triumph of human rationality. There are many ways of reading them that would continue to reinforce this view. But to do so is to miss the radically decentred vision of humanity that each offers up in its own way. The human is ostensibly there at the focus of all of them, but this is a human that takes to the stage alongside singing, flute-playing half-birds, enchanted instruments and babbling streams. It is our own anxiety about non-human agency that surfaces in aesthetic disagreements about these pieces. So long as we continue to get to have those disagreements, perhaps we should consider what these posthuman classics have to teach our confused present.