aleatory (n) — depending on contingency, relying on chance or accident. In particular, “aleatoric music,” for example, the music of John Cage often has aleatoric elements. Random, often overlooked contingency.
Aleatoric music is often invisible to the ear, and usually only heard by icontrast to its sudden absence. It can be manufactured, for example:
The fun of such music arises from the recognition of beauty and music in what would otherwise be ignored as noise — it is something like an exercise of auditory alchemy, turning noise into music, chaos into order. The “tree falls in the forest” paradox becomes more meaningful: unperceived, ignored, overlooked the makes no sound at all; sampled from the aleatory, it becomes not just noise, but music. To rephrase the question in aleatoric terms: if a tree falls in the forest, does it make music?
The Books, another favorite band of mine, depends on aleatoric sound to compose their music, sampling and organizing the random sound from just about everywhere, and even explicitly referencing the word itself.
Etymology – from Latin āleātōrius, from āleātor gambler, from ālea game of chance, dice, of uncertain origin.
(More Books, if you please).