Art and the human spirit fuse in this poem as Yeats attempts to find some way to move outside the problems of the human body. Spirituality in this poem is strongly linked to the body: there’s a constant struggle to figure out exactly where the heart belongs. Is it part of the body? Will it die with the body? Or does it have a life and existence of its own? If so, how can the soul best express itself? Through human communication? Through art? Yeats has got loads of questions – and they don’t necessarily all get resolved here. After all, it’s a pretty short poem.
The speaker’s desire to change bodies is a cop-out: he doesn’t want spiritual re-birth, just a new look.
In "Sailing to Byzantium," art becomes a better vessel for spiritual expression than human action.