“What is that?” – You might ask.
Well! The tonal system, which is capable of transmitting a range of human feelings (from sadness to nostalgia; from despair to heroism), is only recognized as such due to a hierarchy and organization present between the tones.
Why? Because once tone one is played, it cannot be repeated until all others have been played – thus, all twelve chromatic tones of a scale are equal to each other in importance.
In short, what results from Serialism is a cacophony of unbound “musical” horrors!
Screeches and moans; disjointed “melodies” that make no sense....
It's like someone vomited on sheet music!
Worthy of mention: Serialism emerged alongside the modernist movement in all arts at the turn of the 20th century.
Here's a link from Schoenberg's music.