If we say a potentiality is actualized, by necessity the actualization is not a homogeneous process. An actualizing thing is actualized on successive levels, and sometimes to short-circuit a particular level. For example, in fact, let’s take the example of a musical piece: so how does that begin? What could one call the kernel, even before the piece exists? What is it? I’d say what there is — but here I proceed from my own understanding – I would say, you know, at the base of everything in music, there is the ritornello/refrain. The basis is a little refrain. You might say: where is this little refrain? It could be in the air. It’s not human; it could be cosmic. It might be a little refrain over there, in a distant galaxy. So a little refrain, everything starts with that.
Let’s suppose that this little refrain gets seized… — Ah, shit, I no longer have any memory, it’s very odd: each time that I want a precise proper name, it slips away. That’s aging; it’s terrible. Mahler’s “The Song of the Earth,” that’s it. — It gets seized by Mahler. I insist on this because he really is a captor of refrains, but finally he’s not the only one. Already nothing other than his prehension of the eternal object. You see, prehension is no longer prehension of prehension, it’s prehension of an eternal object. The prehension of an eternal object [is] when it’s Mahler who prehends the little refrain; it’s not the same thing when it’s you or me. Why? Because, without speaking about his particular genius, he apprehends already through an entire technical armature that, in some cases, some among you have, but me, I don’t have it. Already these prehensions are different. [There’s a] popular tune, at a Hungarian corner café; I’m having an aperitif with, — ah, there’s another name – next to Bartok, it’s obvious that in the little Hungarian tune that we hear, Bartok’s prehension is different. But I say a little refrain, that could initially be non-sound (non sonore), and the musician grasps it as a sound refrain. For example, a movement: you see two children walking along in a certain way. They don’t need to sing in order for this to be a little refrain.
So there you have it. The eternal object, if you tried to define its kernel, it’s the little refrain. And then what happens? Prehension is a first level of actualization, prehension not of the prehension, but of the eternal object. You see, then, each time it is forking: my prehension of the little refrain connects to other prehensions, and that’s the actual occasion aspect. And on the other hand, it’s prehension of the eternal object, of the little refrain bouncing along in the air. But you say to me: but where does it come from? I wouldn’t tell you. No one wants to ask that! There are philosophies in which there are reasons to ask that, but not here. There is no reason to ask where the little refrain comes from. At that moment, one would answer with insults, a blow from a stick. A blow from a stick is also a little refrain. So we will have answered as was required.
Fine, so, it’s Mahler who gives it obviously — there, prehending, prehending his eternal object, this kind of pure potentiality — who gives it a level of actualization. He goes back home and writes; he takes his music paper and he writes, he writes something. It’s a new level of actualization. He’s really going to compose; he notes down the little phrase there like Vintueil no doubt noted his little phrase. He could have done it on … on his shirt sleeve, [Pause] and he truly composes, a new level of actualization. And nonetheless, it’s still potentiality. It will have to be performed. What is music that hasn’t been performed? It’s already at a high level of actuality, but there you will have to perform it. Yes, that’s enough.
So, for all the examples you have, as long as it hasn’t been performed, to some extent, it must be performed as if the process of actualization demanded this final thing. Specifically the ingression will not be definitive as long as it isn’t created in an occasion that unites all the characteristics of the event. For I could perhaps show that, at each level, there are only certain characteristics of the actual occasion that are realized. But only the performance in concert will yield for music, what, what they called in the Middle Ages the ultimate act, the ultimate act of the form, the ultimate element of actuality. And then, for other disciplines, that doesn’t seem to be the same thing. I don’t have a feeling, for example, that exhibiting in a painting exhibition has the same meaning in pictorial actualization as performing for musical actualization. It’s something else. It’s not… Writing is something else again. What is the ending, what is the ultimate act of writing? There are many authors who thought, in the end, [that] the reading act was required, that is, one had to read. Fortunately, it’s an idea that has disappeared because… because… yes, ok. Fine, you see? All these are problems that we have to ask ourselves.
https://deleuze.cla.purdue.edu/seminars/leibniz-and-baroque/lecture-14#_edn7
The wondrous music of becoming 