what is the difference between good and bad music


my friend says rap is bad music. another friend says mahler is a terrible composer.

is it all subjective, i.e., a matter of opinion ? or are there standards which can distinguish good from bad music, however one defines these terms ?

if there are standards, can one specify them or refer me to a source ?
mrtennis
Hello Redkiwi, Good to see you adding a thread or two. I thoroughly enjoyed your dissertation on component shelf experimentation several years back. It helped me out toward hearing “good music” from “bad music”. Happy Listening!
There is no 'good' or 'bad' music, there IS 'music'. One either likes it or one doesn't.