"The Self-Unseeing" is a poem by Thomas Hardy, and its theme revolves around self-awareness and the passage of time. In the poem, the speaker reflects on a childhood moment captured in a photograph. The theme is about how, as time passes, one's perception of oneself and life changes. It explores the idea that the innocence and unawareness of childhood are lost as people grow older and gain self-awareness. The poem also touches on the idea of nostalgia and the longing to return to a simpler, more innocent time.