ALEATORY MUSIC

The term “aleatory music”—first coined by composer Pierre Boulez, and synonymous with “chance music” and “indeterminacy”—describes the random or chance processes used by composers and performers beginning in the mid-20th century. As early as the 18th century, however, several composers had toyed with a form of chance composition. For example, in his Musikalisches Würfelspiel (”Musical dice game,” 1787), Mozart used dice and number tables to determine the order in which bars of music were performed.

What was considered an innocent parlour game in the 18th century became a cause célèbre in the 20th. At the beginning of the 20th century, many composers began to search for alternatives to what they considered the exhausted tonal tradition—alternatives that included impressionism, folk music, and serialism. By the middle of the century, some composers, and particularly American composers, found even these vocabularies to be at best uninspiring and at worst stifling. One reaction to this crisis was a renewed interest in using chance procedures.

Charles IVES was the first modern composer to experiment with aleatory techniques. His scores gave an unprecedented degree of freedom to the performer, offering wide-ranging alternatives and unrealisable notations. Henry COWELL took Ives’s ideas further, working with several types of indeterminacy, including flexible (or “elastic”) forms and graphic notation—where symbols, spatial distance, or linear diagrams are used instead of traditional notes and staves. An early example of graphic notation is used in Cowell’s piano piece The Tides of Manaunaun (1912), while his String Quartet No. 3 (1934) uses a structural device that allows performers the freedom to assemble their own versions of the work.

The most influential composer, however, to advocate the use of chance techniques was Cowell’s student John CAGE. In Music of Changes (1951), Cage used the Chinese book of divination, the I Ching, to determine the piece’s compositional parameters. He also explored graphic notation. In Aria (1958), for example, he drew coloured wavy lines for the vocalist to interpret, while for Fontana Mix (1958) he created a score out of a series of transparencies laid one on top of another.

Several of Cage’s close associates in the so-called “New York School” also explored indeterminacy. In the “Projection” series (1950-51), Morton Feldman provided his performers with scores notated as graphs wherein pitches and rhythms were given general terms; while Earle Brown’s December 1952 (1952) was notated as an arrangement of black rectangles.

In Europe, one composer who incorporated fully the use of controlled aleatory techniques, especially to effect complexity without causing undue difficulty for the players, was Witold LUTOSLAWSKI. Karlheinz STOCKHAUSEN’S Aus den sieben Tagen (1968), however, uses a type of graphic score that consists only of verbal directions on how the piece is to be performed. Exploiting new technology, Iannis XENAKIS began to use a mathematical process that incorporated probability formulas together with the computer language FORTRAN to write the piece Metastasis (1954).

Behind such experiments was a philosophical aesthetic that continues to be practiced by contemporary composers. John Cage summed up this philosophy well when, in 1973, he wrote: “When I make a piece of music I try not to interrupt in principle the silence that already takes place…. That’s why I employ chance operations: to free sounds from my intentions, my memory, my likes and dislikes.”

Timothy Kloth