The fundamental topic of "Because I Couldn't Stop for Death" is the interpretation of mortal experience through the lens of immortality. The concept of eternity as timelessness is a topic that stems from this. The poet translates these abstractions—mortality, immortality, and eternity—into a series of pictures. By doing so, he gives substance to ideas that would otherwise remain merely concepts. Eternity means forever in any sense other than a limited period. In this poem, the speaker refers only to human life, but the idea behind the phrase is applicable to all existence. Human experience is always limited by time, but beyond the limits of time is infinity. Infinity can be understood as having no end or boundary. It is impossible to reach an end when extending forward in time. As you look back over your life, you will never reach a point where time stops because there is always more history to cover. Infinity also has no beginning; it was here always. Mortality means the state of being mortal or human. It is the condition of being alive right now but knowing that we will one day die. Our lives are characterized by growth and change as we go through life experiences, some good and others bad. The moment we are born, we begin our journey as individuals. We will continue to evolve as people, and at some point we will die.