Nibbāna is the goal of the Buddha's path: the extinguishing of greed, hatred, and delusion; the end of craving and the cycle of rebirth. The image is a fire gone out because its fuel is exhausted. Nibbāna should not be reduced to a calm mood, a pleasant meditation, ethical goodness, or disappearance into a creator. These may support or resemble aspects of the path, but the canonical claim is unconditioned liberation.
Udāna 8.3 speaks of an unborn, unbecome, unmade, unconditioned; because it exists, escape from what is born and conditioned can be discerned. Other passages define Nibbāna in experiential terms as the ending of lust, hatred, and delusion. The texts deliberately approach it through both negation and freedom because conditioned categories cannot turn it into an ordinary object.
Early Buddhist traditions describe four stages. A stream-enterer abandons identity view, paralyzing doubt, and clinging to rules and observances as sufficient; liberation is assured within a limited number of lives. A once-returner further weakens sensual desire and ill will. A non-returner abandons them. An arahant uproots the remaining fetters, including craving for refined existence, conceit, restlessness, and ignorance.
These stages are not personality awards. A stream-enterer may still experience anger and desire, though the roots binding them to lower rebirth are transformed. Claims of attainment are treated cautiously in monastic discipline. Extraordinary experiences, visions, energy, or peace do not by themselves prove a stage. The practical question is which fetters have actually ended and whether greed, hatred, and delusion continue to govern conduct.
At an arahant's death, the texts use parinibbāna. The Buddha refuses the four alternatives that a liberated one exists, does not exist, both exists and does not exist, or neither after death, because each applies categories tied to the aggregates. The course should preserve that refusal rather than inventing a simpler metaphysical picture.
Koṇḍañña first gains the Dhamma eye during the Four Noble Truths teaching. Over subsequent instruction, all five enter the stream. When the Buddha teaches the aggregates as not-self, their minds are freed from the defilements without clinging.
The wanderer Vacchagotta asks whether an awakened one exists after death, does not exist, both, or neither. The Buddha sets all four aside and uses the image of a fire that can no longer be designated by direction after its fuel is gone.