Non-Cagean
This is a weird one, because it’s an invented form of the name of John Cage, who was an experimental composer in the 20th century. Cage was known for using strange and unique musical instruments and styles.
He might be most known for 4′33″, which is a 1952 musical “composition” consisting of four minutes and 33 seconds of silence. He advised that it was for any instrument or combination of instruments, and consisted of three acts. During this “performance,” the orchestra literally sits and does nothing (often while the audience nervously giggles, then erupts in ironic applause – here’s an example).
It was either a joke or a biting commentary on the state of music and attention, depending on who you asked.
Why I Looked It Up
In an article about Spotify music royalties:
They likely will point to examples of bad faith uploads (30 seconds of non-Cagean silence, and so on)
This clearly means “silence not intended as art” … but what does that even mean? That there are different forms of silence, and some can be art while others are just, well, silence?
Weirdly, I did find “non-Cagean” in reference to some other situations:
The daring element of the venture was that the conductor had never attempted a fully notated (non-Cagean) score in public.
The same applies to music of a non-Cagean kind (some of Cage’s works are, characteristically, recordings – rather than representations – of everyday sounds), literature, poetry, theater, sculpture, and dance.
What this actually means is anyone’s guess.
Postscript
Added on
There’s an interesting point about 4’33” made in 100 Essential Things You Didn't Know You Didn't Know about Math and the Arts.
Four minutes and 33 seconds is 273 seconds. -273C is temperature of absolute zero. Was Cage proposing that his musical piece represented the “absolute zero” of sound?
Postscript
Added on
Interestingly, John Cage is also known for “As Slow as Possible,” which is a musical composition where the notes are meant to be held (on organ) for as long as possible. One performance, currently underway, will last 624 years.