ABSTRACT
The Concert for Piano and Orchestra by John Cage was composed in 1957–58. At that time, Cage was involved with the concept of indeterminacy, making what he called “a work indeterminate of its performance.” As a composing means, he was already using chance operations since 1951, first in the Concerto for Prepared Piano and Chamber Orchestra, next in Music of Changes, and then in other subsequent pieces. However, there is a difference between the use of chance procedures as a means of composition and indeterminacy. Chance procedures imply the way the composer works, and indeterminacy is more related to the perception of a piece. With the I Ching (Book of Changes), an ancient Chinese book of oracles, Cage used the sixty-four hexagrams on which it is based in order to find unpredictable answers to previously devised questions. In fact, the answers were also previously devised, but there was more than one answer for one question. The tossing of coins required by the I Ching consultation was used in order to decide which answer should be kept for a specific question, after having related each answer to a number or a group of numbers of the hexagrams of the I Ching. The questions used would be of different kinds, affecting different aspects of the composition, from the overall format to specific ways of articulating a note for the performer. In indeterminacy, the score leads to a completion by the performer, making the result unique but open and allowing for many possible realizations. Each one is then complete in itself but not definitive, that is to say, without using all the manifold possibilities given by the score.
