Aleatoric music

Aleatoric music uses chance procedures or controlled indeterminacy to shape composition or performance. Its outcomes may vary between performances while remaining guided by a composer’s framework.

Indeterminacy (music): A musical practice in which some compositional or performance outcomes are left unspecified. It names the deliberate openness that distinguishes many aleatoric works.
Music of Changes: A piano composition by John Cage, completed in 1951, whose materials were selected using the I Ching. Cage used chance procedures to determine many details while composing this fixed score.
John Cage: An American composer whose experiments with chance and indeterminacy reshaped postwar music. His chance compositions became central models for aleatoric practice.
Serialism: A compositional method that organizes musical parameters through ordered series of values. Its systematic control of musical choices contrasts with chance-based selection.
I Ching: A Chinese classic used for divination through the interpretation of hexagrams. Cage used its chance-based consultations to make compositional decisions.
Chance operation: A procedure that uses random or arbitrary selection to make a decision. Composers use such procedures to generate or choose musical material.
4′33″: A 1952 work by John Cage in which performers make no intentional sounds during its three movements. Its variable environmental sounds expose how a performance frame can leave musical content open.
Pierre Boulez: A French composer and conductor known for modernist music and rigorous serial techniques. Boulez criticized unrestricted chance and advocated tightly controlled forms of musical choice.
Indeterminacy in music: The condition in which aspects of a musical work or performance are not fully specified. The term overlaps with aleatoric music but can emphasize openness rather than chance procedures.
Dadaism: An early twentieth-century avant-garde movement that rejected conventional artistic logic and embraced chance. Dada experiments helped establish chance as an artistic procedure before its musical use.

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