Aleatoric music began in Darmstadt in 1957 when serialists embraced chance

Evidence

In Darmstadt in 1957, two of the most resolute supporters of serial music, Karlheinz Stockhausen and Pierre Boulez, marked the beginning of a new phase in contemporary music: Stockhausen with his new Piece for Piano XI, and Boulez with a lecture entitled Alea' (dice’). The new phase was called aleatoric music. Aleatorics signified involving chance elements in both composition and interpretation: for example, certain parts of a composition could be interchangeable, or parts which the composer had only recorded in sketch form could be open to free interpretation in performance. Aleatorics involved elements of Dadaism and Zen Buddhism, introduced mainly by John Cage and Mauricio Kagel. In 1958 Cage launched a decisive assault on serial orthodoxy with the performance of his Imaginary Landscapes No. 4 for twelve radios, played like normal musical instruments in four-four time, creating an `ordered chaos’. — Rolf Wiggershaus, The Frankfurt School, 2197

Categorization

• XREF: Connects to Adorno’s critique of musical rationality and the ‘administered world’ discussed throughout the book — Cage’s ‘ordered chaos’ is the aesthetic revolt that follows.
• SEED: Angle for an essay: aleatoric chance as a musical analog of democracy — the audience becomes co-author, mirroring debates about participation within structured systems.