"Rick Rubin has a larger looming presence on this album than his 'thank you' deserves. He asked 'Why can't more people cover U2 songs?' And it's because, with all the great sounds and arrangements, you can forget that there isn't a song there."
- Bono on Rubin's influence on Songs of Innocence
The song 'Two Hearts Beat As One' is a love song from Bono to Ali and refers to a baby when it is in it's mother's womb.