Memory in “Theories of Time and Space” is given symbolic significance in reference to its weight and definition. Although the speaker is clearly convinced of the truth of their assertion that “there’s no going home” (Line 2), there is also a sense within the poem that memory is powerful enough to exist outside of the constraints of time and space. Although people and places cannot help but change over time, human memory just as powerfully continues to draw people back to specific places in the hopes of finding a home or loved one somehow unchanged by time and circumstance. Near the end of the poem, Trethewey writes, “Bring only / what you must carry—tome of memory / its random blank pages” (Lines 14-16), turning memory into something that is weighted and heavy—a “tome” or large book that is impossible to lose and also impossible to ever completely fill up.

Similar to the “tome of memory” (Line 15), still photography as an instrument used to capture a moment in “time and space” is symbolically significant within Trethewey’s “Theories of Time and Space.” The poem concludes with the image of a photograph: “someone will take your picture: / the photograph—who you were— / will be waiting when you return” (Lines 18-20).