A world of immortality is inherently inconceivable, if not downright unpleasant to think about. Sustaining life (or postponing death, depending on your point of view) is what makes life worth living. Eating, sleeping, working, playing, procreating… this is all the process of sustaining our lives; of avoiding death. Having a life without death would be like having a bicycle without pedals. It just wouldn’t go anywhere or do anything. There would be no reason for it.