Tim Morton stages a post on Ontolojazz in the following way:
These are ephemeral objects indeed, these jams. It's quite precious to have records of them. Anyone can download an mp3 of some “live” performance, with an ease that smoothes over the strangeness and difficulty of playing together, let alone of simply coexisting.
Trying to figure out why jamming is different from classical playing will take me some time. There are obvious reasons. You're not reading music, you're “reading” your inner state and your instrument and the people in the room, and a tune that you may be working on, perhaps a standard that you're reworking. This leads me to the inescapable conclusion, which I hinted at below, that the configuration space of jazz includes “classical” music as a much smaller, rather oddly stabilized and crystallized island within it.
I want to speak to the difference between ‘jamming’ and performing music notated in the Western classical tradition.
Let’s start with the obvious: No matter how complete the notation, the music’s not there on the page. There is a difference between playing the notes and playing the music. The notation requires interpretation if it is to be realized in an authentic performance, a moving one, a charismatic one. Interpretation requires intuitive knowledge of the inner life of music. And so does jamming. But jamming can be just as empty as a classical performance that gets the notes but misses the music.
One of the things that needs to be understood, then, is how that could be so. What are the mechanisms in play? We don’t know.
So, let’s put that aside and talk about neumes, which are the roots of Western musical notation. According to the Wikipedia the word itself is a Middle English corruption of the Ancient Greek word for breath (πνεῦμα pneuma). As the Wikipedia says, “the earliest neumes were inflective marks which indicated the general shape but not necessarily the exact notes or rhythms to be sung.” These inflective marks were placed above the words for plainsong. Because the neumes only indicated the shape of the melody they would have been useless for someone who didn’t already know a given chant. For any number of different melodies can share the same general shape.
Rather, neumes are mnemonic aids. If you were already familiar with a chant, then the neumes would help you to remember what you’d sung the previous time, and the time before that, and so on. Think of them as the graphic hooks on which you catch the melodic fish that are already swimming about in your mind.
On the improvisation side of the ledger, think of “your inner state and your instrument and the people in the room, and a tune that you may be working on . . .” as the environmental hooks (yes, your inner state is part of the musical environment) on which you catch the melodic fish that have been swimming about in your mind since forever. The parallel’s not quite exact, not quite a parallel, more like an oblique if you will. But it’s enough to get some thinking going.