At first, it refers to the knowledge about music, and later it has the meaning of discipline. It is a learning realm that enjoys it. There are three different realms of learning: knowing-liking-enjoying. "Knowledge" emphasizes rationality. You are you and I am me. I just learn knowledge passively, and I can't master it freely. "Like" touches emotions, generates interest, likes learning, gives up if you don't like it, and can't last long; "Enjoy" is the realm of "people who enjoy". Learning is "devoted" and almost "intoxicated", and such people are never tired of learning.