Impermanence is a key characteristic of Buddhist philosophy. It is difficult to imagine Buddhist philosophy without the concept of impermanence. Where Western religions and Brahmanical religion assert the reality of an enduring, immortal soul (or self), the Buddha dispensed with the notion of eternity, including the possibility of beings that are bound to persist forever.
In Buddhist thought, the concept of impermanence is illustrative of the way things are. Further, if impermanence is understood by a practitioner, then the practitioner has gained therapeutic benefit. Craving, borne from delusion, is at the root of the Second Noble Truth. Craving for something (anything!) to exist forever conflicts with the basic truth of impermanence.
Buddhists do not embrace the idea of an eternal afterparty in which souls reunite for a blissful eternity. The therapeutic benefit is found when the practitioner is faced with actual loss. Loss is inevitable. Even the heavenly realms of rebirth have a time limit imposed on its residents’ lives. This truth is foundational to Buddhist philosophy and practice.