It's basically a song about shedding your ego and evolving.
http://www.acs.appstate.edu/~davisct/nt/jung.html#shadow http://www.lcc.ctc.edu/faculty/dmccarthy/engl204/seven-lecture.htm "The very clearest and most articulate discussion of this subject is contained in Johnson’s book Owning Your Own Shadow. The Shadow is not a difficult concept. It is merely the “dark side” of the psyche. It’s everything that doesn’t fit into the Persona. The word “persona” comes from the theater. In the Roman theater, characters would put on a mask that represented who the character was in the drama. The word “persona” literally means “mask.” Johnson says that the persona is how we would like to be seen by the world, a kind of psychological clothing that “mediates between our true elves and our environment” in much the same way that clothing gives an image. The Shadow is what doesn’t fit into this Persona. These “refused and unacceptable” characteristics don’t go away; they are stuffed or repressed and can, if unattended to, begin to take on a life of their own. One Jungian likens the process to that of filling a bag. We learn at a very young age that there are certain ways of thinking, being and relating that are not acceptable in our culture, and so we stuff them into the shadow bag. In our Western culture, particularly in the United States, thoughts about sex are among the most prevalent that are unacceptable and so sex gets stuffed into the bag. The shadow side of sexuality is quite evident in our culture in the form of pornography, prostitution, and topless bars. Psychic energy that is not dealt with in a healthy way takes a dark or shadow form and begins to take on a life of its own. As children our bag is fairly small, but as we get older, it becomes larger and more difficult to drag."