He was speaking of the central set piece of the film, the song "The Origin of Love" (video after the jump - be warned there's non-pornographic cartoons of nekkid people). Hedwig, a transsexual German rocker who tells the story of her life through her music, uses the song to share a parable from Plato's Symposium, a philosophical work that seeks to explain the very nature and purpose of love. Mitchell/Hedwig's tale is taken from a satirical speech by Aristophanes.
Aristophanes posited that romantic love is a desire for wholeness; that long ago, people had two heads, four arms and four legs, but then the god Zeus split them all in two, and we must now spend our days searching for our other missing half.
Hedwig, the lovelorn victim of a botched sex-reassignment operation, is missing vital parts of herself in a number of ways, and Mitchell's musical exploration of the myth -- accompanied by a delightful animated sequence -- is both comforting and sad:
Last time I saw you, we had just split in twoIf you haven't seen Hedwig and the Angry Inch, don't shy away because of its campier elements -- along with a lot of raucous, raunchy humor there's a deep, complicated heart at its center, and messages about love that speak to everyone.
You were looking at me, I was looking at you
You had a way so familiar, but I could not recognize,
'Cause you had blood on your face, I had blood in my eyes
But I could swear by your expression
That the pain down in your soul
Was the same as the one down in mine
That's the pain, cuts a straight line
Down through the heart; we called it love
And if you have seen Hedwig ... well, pull it out and watch it again. Reaquaint yourself with the origin of love.