Indeterminacy

Indeterminacy is a compositional approach in which some elements of a work — pitches, durations, ordering, instrumentation or the sounds themselves — are left undecided by the composer and determined instead by chance operations or by performers at the moment of performance. Codified by *John Cage* in the 1950s through the use of the I Ching, coin tosses and star charts, it rejects the idea of the score as a fixed object: two performances of the same piece may share almost nothing. It overlaps with aleatoric music, graphic scores, text scores and free improvisation, and remains a foundational technique of experimental music.