Pablo Massa replies to me:

>>I'm always wary of blanket statements about entire genres of music,
>>particularly railing against specific techniques.Technique is neutral,
>>I should think.
>
>Right, but chance is not a technique.  Sounds strange, but please remember
>the classical meaning of the word "technique".

You're confusing performance realization with the technique of composition.
An aleatoric composer builds (thus satisfying the meaning of the word
"technique") a frame in which something can be realized.  After all, no
aleatoric composition is completely random.  That is, as far as I know, no
aleatoric score says "anything and everything may happen." Instead, there
are certain fixed elements - at the very least, the instrumentation; often,
cells of actual notes and rhythms.

As for the "can you tell one composer from the other" objection, no.
But then again, I often confuse Haydn, Mozart, and early Beethoven.
Furthermore, it's an objection that ignores the essence of aleatoric
composition.  You're asking me to decide on the basis of listening to
a realization, not on the basis of the composed elements.

Steve Schwartz