Reilly explains that the center of Schoenberg’s revolt was his rejection of tonality. He denied tonality existed in nature as the property of sound itself, a view of music held from ancient Pythagoras right up until his day. His revolutionary view was developed not from scientific advances in acoustics but from Schoenberg’s desire to escape all of the ancient restrictions on sound, saying “I am conscious of having removed all traces of a past aesthetic.” As Reilly clarifies:

Schoenberg took the twelve equal semitones from the chromatic scale and commanded that music be written in such a way that each of these twelve semitones be used before any one of them is repeated. If one of the semitones is repeated before all eleven others are sounded it might create an anchor for the ear, which could then recognize what was going on in the music harmonically. The twelve tone system guarantees the listener’s disorientation. Schoenberg proposed to erase the distinction between tonality and atonality by immersing man in atonal music until, through habituation it became the new convention. Then discords would be heard as concords. As he wrote, ‘The emancipation of dissonance is at present accomplished and twelve-tone music in the near future will no longer be rejected because of discords.’

Schoenberg was not exaggerating. He overcame 2,000-year-old conceptions of tonality, concord, and harmony to set discordance as the new standard for modern music. But once beauty in the classical sense was upended, why stop there? His disciple, French conductor and composer Pierre Boulez, took it further and applied the same principle of tone row pitch to all the elements of music—pitch, duration, tone production, intensity, and timbre. Another French disciple, Edgar Varese, asked why even 12-tone at all? Even he could not abandon all order, though. The American composer John Cage went the whole way and simply “created noise through chance operations.” Now you know why it sounds so ugly. That is its point.