In Margaret Atwood's "Marrying the Hangman," the speaker states,

To live in prison is to live without mirrors.

This line in the poem suggests that living without oneself, represented by one's reflection, is not living. Atwood uses the mirror as a metaphor for one's own presence in one's life and suggests that, without it, one is necessarily lost or captive.

If the rest of the poem is examined, however, the meaning becomes much deeper. As the poem continues, we find that the speaker uses a hole in a stone wall in place of a mirror. From the hole comes a voice, and "This voice / becomes her mirror." The voice then becomes a receptacle for her creation of identity.

Overall, Atwood is stating that people cannot exist freely without a clear sense of themselves.