How emergence relates to music.

Musical Precedents

Throughout recent history, mankind's approach to music has been consistent. Time is taken as the canvas upon which music is written, it is divided and subdivided into increasingly smaller periods (usually by dividing in two or some small integer), and sounds--notes, percussive sounds, etc --are placed upon this canvas. The frequencies, tones, scales, and timbral qualities of the music vary between cultures, but underneath it all lies the paradigm of placing sounds (or more commonly musical phrases) in a structured stream of time. Music is constructed by taking these notes or phrases and layering them atop one another. Harmony (where it exists) arises from the simultaneity of multiple sounds. Melody is a transformation in time of a musical phrase or of a construction built up from multiple musical phrases.

The aesthetics of the process varies, but the process is fundamentally one of synthetic construction and elaboration of a musical idea, goal, or intention.

In the mid 20th century some musicians and composers started to focus less on the musical intention and more on the generative process. John Cage, for example, started exploring the implications of aleatory processes. He would take some random or statistical process -- say, ink falling upon a blank sheet of music or the random tuning and re-tuning of radio receivers -- and devise a way of translating those processes into music. The results were often interesting, but they also often resulted in difficult musics.

In his seminal work In C, Terry Riley approached music in an aleatory way, but one in which the aesthetic preferences of the musicians tempered the strict stochastic processes of John Cage. This work used 53 short musical phrases that were given to a group of musicians along with some guidance upon how they should order and choose these phrases, but the actual decisions were left to the musicians to make in order to fulfill the aesthetic qualities of the piece as it was performed.

Both Cage and Riley can be thought of as composes working in the field of process music, which is a term used by musicologist to describe musical compositions that focus on the generative process more than on the aestheic intention of the composer. The terms was coined in the late 1960's by the minimalist composer Steve Reich, but elements of process music can be seen much earlier, beginning probably in the 1940's. Like with Cage and Riley, process music often makes use of statistical or aleatory processes so that the strict aesthetic desires of the composer can be somewhat transcended, brining process to more emphasis.

Within the "process" composers and musicians began making liberal use of modern technologies. Brian Eno and Robert Fripp, for example, used long-delay tape looping to construct musical compositions.

The move towards process was also a move towards musical emergence, and it was concomitant with a subtle shift in world-view that was taking place in the mid 20th century. This shift, powered by the conceptual shifts taking place in 20th century science and thinking, was towards something new for modernity, although in can in some ways be seen as a recapitulation of views that existed in previous times.

Time and Space

From the time of Issac Newton onward, the view that was coalescing into what we now consider modern thought was one of absolutes. Time was seen as absolute. Space was seen as absolute. And while some distinguished scientist and thinkers took exception to this (notably Leibniz and Mach), it more or less held as the dominant paradigm until the proposals of Special Relativity.

And this view is reflected in the dominant musics. Like in the sciences, time and space are seen as absolute. Time is divided and subdivided, and notes are placed within that continuum. Furthermore time as seen as linear and infinite, or at least very long. Space as seen also as a linear continuum. This is perhaps reflected in our attitudes towards frequency and pitch. Absolute, defined pitches are established. In previous times scale intervals were complex and nuanced, but in the 16th century the process of reducing all intervals to equivalence began, so that by the 18th century almost all music used intervals which were precisely, mathematically defined to be equivalent. Whereas before different scales were different in interval, by this time scales became the same, shifted only in frequency. By the time the Industrial Revolution was in force the transformation was complete. Notes (like people, perhaps), were seen as equivalent and interchangeable. People become "the public," goods become products, and all musical intervals become factors of a precisely defined mathematical constant (the 12th root of 2).

But with the advent of new musical styles such as minimalism and process music the west started to reexamine this. Composers became more aware and interested in the interactions that could arise between sounds, and they started to think of time in new ways. They also regained an interest in micro-, non-standard, and nuanced tunings. Musician and composers rediscovered the musics of cultures not their own.

By now, in the sciences absolute time and space have given way to relative spaces and times. Not surprisingly, the formalisms I've developed for this work mirror these changes in many ways, as did the work of some of the more creative composers begining in the mid 20th centruy.

Music and Emergence

The specific formulation of musical emergence used in this work is examined elsewhere; here I wanted to say a few words about music and emergence in general.

In some ways parts of all music are emergent. Harmony, for example, is a perceptual property that arises from a simultaneity of notes. Note sound and we hear them, but we also hear the relationship between the notes--the harmony--as a thing in itself.

Scientists tell us that dogs' sense of smell, in addition to being more acute than ours, also works differently. When we are presented with a smell we tend to experience the gestalt of it. A dog will smell the components of a smell individually. It takes great training and experience in cooking to discern the ingredients of a dish be smell alone. Dogs do this naturally. It is not too much or a stretch of the imagination to imagine a nervous system that can hear sounds and notes clearly but doesn't perceive the harmony. But that wouldn't be our nervous system, for harmony is something we perceive and understand at a very deep level. Even very small infants with no real cultural exposure respond strongly to harmony, scientists (and parents) also tell us.

In a similar way, the perception of melody is hard-wired into our brains through our pattern-matching abilities. Composers and musicians often work hard to construct a good or memorable melody, and listeners have the innate ability to perceive it, even if they are untrained and don't understand what's happening in an intellectual way.

Any exploration of musical emergence will make use of these human propensities, and unless the desire is to create difficult, academic music, the explorations should be structured in such a way to allow some perception of harmony and melody to arise.

Next, emergence arises from the local interaction of component parts, not hierarchical imposition of design. Thus serious consideration should be given to the avoidance of absolute quantities in deference to local ones. Systems that allow notes to be placed in absolute frequency, for example, are perhaps more likely to grow through design than those in which pitches are relative. It is perhaps best that any logic embodied in the system not have access to absolute information. Notes (or transformative rules or sub-processes or any other entity) should not "know" where they are, beyond knowing where they are in relationship to other entities.

The properties and processes that have shown strong emergence in other domains--such as iteration and self-similarity--should be considered potentially fruitful avenues of exploration for musical emergence (and are fact used in the specific formalisms I developed for this work).

These comments may sound abstract (or perhaps even hard to understand), but they should become clearer when given concrete form and examined with a specific formalism for the creation of emergent musics.

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For information on the specific theory of musical emergence used in this work, see A Theory of Emergent Music.