The speaker looks hard at what we are made of and finds it both thrilling and frightening. The poem begins with a decaying corpse and a hallucinogenic trip, two ways of watching the human body come apart. Matter, the speaker says, holds together despite having no feeling for our longing or loneliness. The real horror isn't gore but "cold necessity," like learning in school that we are made of cells and atoms, mostly empty space, with the clock mocking any sense of turning time.
In the last stanza the tone softens into a kind of wistful regret. The speaker imagines teachers telling a different story: that matter is rare, and that a lover's touch is somehow sustained by invisible forces. Even a dead body, they suggest, might have been a comfort, leaving traces for millions of years. The closing image of footprints ending at a fossilized beach holds joy and disaster together. The mood is curious, unsettled, and strangely tender.