  So far, Dasein's existence has been understood as thrown projection plus falling. The projective aspect of this phenomenon means that, at each moment of its life, Dasein is Being-ahead-of-itself, oriented towards the realm of its possibilities, and is thus incomplete. Death completes Dasein's existence. Therefore, an understanding of Dasein's relation to death would make an essential contribution to our understanding of Dasein as a whole. But now a problem immediately presents itself: since one cannot experience one's own death, it seems that the kind of phenomenological analysis that has hitherto driven the argument of Being and Time breaks down, right at the crucial moment. One possible response to this worry, canvassed explicitly by Heidegger, is to suggest that Dasein understands death through experiencing the death of others. However, the sense in which we experience the death of others falls short of what is needed. We mourn departed others and miss their presence in the world. But that is to experience Being-with them as dead, which is a mode of our continued existence. As Heidegger explains: