"There is no meta-theory in psychopathology. Also, same thing is valid on other sciences and perceptions. Whatever you read or watch please be careful about explanations which is whether meta theory or not" Prof. Dr. Levent Kuey
I would like to add another word to this; if it is so, there is no one answer of one question. The point is that what do you want to learn?
So, just listen to music;