I have heard very few songs with such a gorgeous
melancholy as "I've Seen It All." Ostensibly about a woman coming to terms with and accepting her
blindness, it goes deeper than that. Selma is singing about her
satisfaction of getting all that she ever wants, not only out of
eyesight, but also out of life itself. It was a
sad life, and there isn't really much reason to live longer and see more. It is in this song that we understand that Selma is ready to die - it is spookily
foreshadowing the rest of the film.
The tempo of the song is that of a death march, which is why I classify this song as a suicide anthem.