The postmortal refers to the cure for aging administered to most adults in the novel. The few who reject the cure are referred to as “organics” and are often looked down upon for their stance. The world Magary creates underscores both the positive and negative effects of aging, filtered through the lens of those suddenly trapped to witness the passing of time. Over the course of five decades, Magary exposes the way aging impacts society and the world, creating a clear argument in favor of aging despite its apparent ramifications.

John pursues the cure because of the negative consequences of aging. He equates age with dying and thus seeks the cure to remove one potential cause of death. Aging is, from the novel’s onset, linked to dying in a way that is meant to compel the reader into thinking about the negative consequences of aging. Many of the novel’s “organic” characters are discussed in connection with diseases or conditions linked to age—an anarchist who is dying of cancer vehemently rejects the antiaging cure, while Solara’s sister regrets receiving the cure and is ultimately put in a home for people with dementia. Some characters showcase how agelessness lets them interact with their families in a more intergenerational way, such as the nurse who helps John’s father.