From what I understand musical isomorphism is the formal way to speak about raising the index of a vector field (refer here). But what I don't understand is why is it called musical isomorphism! In the Wikipage, the following is said:
The exact origin of this notation is not known, but the term musicality in this context would be due to Marcel Berger
Was there any documentation on what exactly was musical in this to Marcel? BTW I am using the word musical in the following sense:
Musical, also called musical comedy, theatrical production that is characteristically sentimental and amusing in nature, with a simple but distinctive plot, and offering music, dancing, and dialogue.