Iannis Xenakis, the Initiator of a New Phase in 20th Century Music: Aleatorism

Abstract

Observing the deadlock reached by serial music at the beginning of the 50's, especially in the music of Pierre Boulez - of an immense density - but obtained through an extremely exhausting compositional effort in order to respect the serial rules, Iannis Xenakis is realizing that these densities can be obtained through other techniques offered by mathematical approaches such as Markov chains and the calculation of probabilities. The idea itself can be compared to that of Schonberg, 50 years ago, when, noticing the huge coefficient of chromaticism and dissonance in Wagner's music, obtained (also with great effort) on the principle of tonal functionalism, he totally simplified the technique to obtain these chromatic melodies and dissonant chords on the principle of dodecaphonism. Relatively in the same way, Iannis Xenakis opens a new musical historical stage through these techniques by appealing to mathematical science for the calculation of the chances implied by the game of dice (alea). Xenakis's suggestion then inspired other ways for performing the game of chance, to composers who did not master the science of mathematics, unleashing the freedom of imagination, these composers being almost all in the generation 50s-80s till nowadays: John Cage, Krzysztof Penderecki, Gyorgy Ligeti, etc.