How, then, is an audience to follow a 12‑tone composition on first, second, or third listening? The answer: with a level of engagement, focus, and sympathy that must go far beyond the level of engagement, focus, and sympathy brought to tonally centric music. Whether this is good news or bad news depends on the individual listener, though for the general musical audience, it is bad news.
Certainly, the best 12‑tone works are among the best and most important music composed during the 20th century. But it is still difficult music, and much of that difficulty stems from the intrinsically self‑referential nature of its pitches.
How's pitch set "self-referential", but not M3 or P5, the building blocks of functional tonal harmony? Anyone with a B.Mus. will accept the two quotes beneath on the importance of the "perfect fifth".
The musical language itself became contextual, subject to the taste and expressive whims of the individual composer. For the first time since the 15th century, the perfect fifth—a musical interval spanning seven semitones—no longer governed the harmonic language of cutting‑edge Western concert music.
Schoenberg believed in melody more than anything else. As the first years of the 20th century progressed, he ceased to believe in the tonal harmonic system. By 1908, Schoenberg had come to the conclusion that functional harmony stifled and constrained melody by forcing it to adhere to what he believed were “artificial” constructs: chords built by stacking thirds and chord progressions based on harmonic motion by perfect fifths.
Greenberg uses "self-referential" on p. 49 too - see screenshot beneath.