In the poem, the earth has a cyclical relationship with humankind. When we are alive, the earth supplies us with nourishment and emotional stability, echoing back our good moods and ameliorating our bad ones. When we die, we return to place where we came from: “Earth, that nourished thee, shall claim / Thy growth, to be resolved to earth again” (Lines 23-24). Dead bodies rot and dissolve into their constituent parts “To mix for ever with the elements, / To be brother to the insensible rock” (Lines 27-28), which means the flesh of each person breaks down into the building blocks that make up new future living things, continuing the cycle of sustenance and reclaiming.

Another symbol in “Thanatopsis” is the “mighty sepulchre” (Line 38) that contains all the dead people from all of human history. This metaphorical tomb is the eternal resting place for everyone, housing “patriarchs […] kings, / The powerful of the earth—the wise, the good” (Lines 35-36), alongside regular people like the poet and his readers. This tomb is a place where human divisions no longer matter, as people who held status, power, and wealth will be with those who had none, and people of many different “tribes” (Line 50) will now have no national distinctions between them.