At its best, and perhaps most romantic, interpretation, music is the attempt to leave more than some ephemeral mark upon the Universe. Our passing through this life - it can be meaningless, violent, short.
Or, we can do some thing, some dark matter that cannot be defined, cannot even be named, yet makes its presence known through what it does. Even as we pass, that moment, that transcendent point, declares "I am I know". And it can last forever.