ABSTRACT
In aleatory music, some of the final decisions as to the exact materials used in a composition or the way they are used are often left to the performer, who makes the decision at the moment of the actual performance. By the end of the 1950s, both general trends (control and chance) merged in the works of some composers, and various styles, including various types of sound-mass composition, resulted from the combination of partial control and partially aleatory procedures. The term “chance,” in the context of Cage’s music, refers to the use of compositional procedures that involve randomness in the choice of musical events. The term “indeterminacy,” on the other hand, refers to a process in which a piece allows the performer a variety of choices (left indeterminate by the composer). In the case of Lutoslawski’s music, form is usually predetermined, and so is the general, overall harmonic result, while exact simultaneities are not.
