aleatory music [Lat. alea=dice game], music in which elements traditionally determined by the composer are determined either by a process of random selection chosen by the composer or by the exercise of choice by the performer(s). At the compositional stage, pitches, durations, dynamics, and so forth are made functions of playing card drawings, dice throwings, or mathematical laws of chance, the latter with the possible aid of a computer. Those elements usually left to the performers' discretion include the order of execution of sections of a work, the possible exclusion of such sections, and subjective interpretation of temporal and spatial pitch relations. Also called "chance music," aleatory music has been produced in abundance since 1945 by several composers, the most notable being John Cage, Pierre Boulez, and Iannis Xenakis.

(from Latin, alea: “dice game”) Any 20th-century music, particularly that of the 1950s and '60s, the composition or performance of which incorporates elements of chance. In aleatory music aspects such as the ordering of a piece's sections, its rhythms, and even its pitches are decided at the moment of performance. When not purely improvising, players follow lists of arbitrary rules or interpreted “graphic” notation that merely suggest the sounds. Charles Ives and Henry Cowell had used such techniques, but John Cage became the principal figure in aleatory; other aleatory composers include Earle Brown (1926–2002), Morton Feldman (1926–87), and Pierre Boulez.

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Aleatory means "pertaining to luck", and derives from the Latin word alea, the rolling of dice. Aleatoric, indeterminate, or chance art is that which exploits the principle of randomness.

Literature

An example of aleatory writing is the automatic writing of the French Surrealists involving dreams, et cetera. The French literary group Oulipo for example saw no merit in aleatory work and its members altogether eliminated chance and randomness from their writing, substituting potentiality as in Raymond Queneau's Cent Mille Milliards de Poèmes (Hundred Thousand Billion Poems).

Luke Rhinehart's novel The Dice Man tells the story of a psychiatrist named Luke Rhinehart who, feeling bored and unfulfilled in life, starts making decisions about what to do based on a roll of a die.

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

Music

Pierre Boulez applied the term aleatoric music to his own pieces to distinguish them from the indeterminate music of John Cage, though both are often described as aleatory. While Boulez purposefully composed his pieces to allow the performer certain liberties with regard to the sequencing and repetition of parts, Cage often composed through the application of chance operations without allowing the performer liberties. Another prolific aleatory music composer is Karlheinz Stockhausen. Qubais Reed Ghazala, founder of the circuit-bending chance-music movement, is an important contemporary chance artist also pioneering aleatoric work in visual media (original techniques in suminagashi, dye migration, aperture shift photography).

Film

In film-making, there are several avant-garde examples; Andy Voda's "Chance Chants" (1979) was created completely using various chance operations (coin flip, choosing words out of a hat, a recorded "telephone game", the vagaries of tracing over drawings) in the decision-making for each creative choice. It was a three part film, the first part being a hand-made computer film, the second a visualization of Allison Knowles' computer poem "House of Dust", and the third a visualization of evolution through a children's telephone game. Fred Camper's SN (1984, first screening 2002) uses coin-flipping to determine which three of 18 possible reels to screen and what order they should go in (4896 permutations). Barry Salt, now better known as a film scholar, is known to have made a film, Permutations, six reels long which takes the word aleatory quite literally by including a customized die for the projectionist to roll to determine the reel order (720 permutations).

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