Aleatoricism

Aleatoricism (or aleatorism) is a term for musical compositions and other forms of art resulting from "actions made by chance".

The term was first used "in the context of electro-acoustics and information theory" to describe "a course of sound events that is determined in its framework and flexible in detail", by Belgian-German physicist, acoustician, and information theorist Werner Meyer-Eppler. In practical application, in compositions by Mozart and Kirnberger, for instance, the order of the measures of a musical piece were left to be determined by throwing dice, and in performances of music by Pousseur (e.g., Répons pour sept musiciens, 1960), musicians threw dice "for sheets of music and cues". However, more generally in musical contexts, the term has had varying meanings as it was applied by various composers, and so a single, clear definition for aleatory music is defied. The term was popularised by the musical composer Pierre Boulez, but also Witold Lutosławski and Franco Evangelisti.

Its etymology derives from alea, Latin for "dice", and it is the noun associated with the adjectival aleatory and aleatoric.

Aleatory should not be confused with either indeterminacy, or improvisation.

In different fields

Architecture

Sean Keller and Heinrich Jaeger coined the term aleatory architecture to describe "a new approach that explicitly includes stochastic (re-) configuration of individual structural elements — that is to say 'chance.'"

Art

Literature

Charles Hartman discusses several methods of automatic generation of poetry in his book The Virtual Muse.

Music

The term aleatory was coined by Werner Meyer-Eppler in 1955 to describe a course of sound events that is "determined in general but depends on chance in detail". When his article was published in English, the translator mistakenly rendered his German noun Aleatorik as an adjective, and so inadvertently created a new English word, "aleatoric".