THIS [FOURTH NOBLE] Truth announces that when craving is removed suffering ceases and nirvana is attained. As will be recalled from the story of the Buddha's life, nirvana takes two forms: the first occurs during life and the second at death. The Buddha attained what is known as "nirvana-in-this-life" while sitting under a tree at the age of 35. At the age of 80 he passed away into "final nirvana" from which he would not be reborn.
"Nirvana" literally means "quenching" or "blowing out," in the way that the flame of a candle is blown out. But what is it that is "blown out"? Is it one's soul, one's ego, one's identity? It cannot be the soul that is blown out, since Buddhism denies that any such thing exists. Nor is it the ego or one's sense of identity that disappears, although nirvana certainly involves a radically transformed state of consciousness which is free of the obsession with "me and mine." What is extinguished, in fact, is the triple fire of greed, hatred, and delusion which leads to rebirth. Indeed, the simplest definition of nirvana-in-this-life is "the end of greed, hatred, and delusion" (Samyutta Nikaya, I, 38). It is clear that nirvana-in-this-life is a psychological and ethical reality, a transformed state of personality characterized by peace, deep spiritual joy, compassion, and a refined and subtle awareness. Negative mental states and emotions such as doubt, worry, anxiety, and fear arc absent from the enlightened mind. Saints in many religious traditions exhibit some or all of these qualities, and ordinary people also possess them to some degree, although imperfectly developed. An enlightened person, however, such as a Buddha or an Arhat, possesses them all completely.
What becomes of such a person at death? It is in connection with final nirvana that problems of understanding arise. When the flame of craving is extinguished, rebirth ceases, and an enlightened person is not reborn. So what has happened to him? There is no clear answer to this question in the early sources. The Buddha said that asking about the whereabouts of "an enlightened one" after death is like asking where a flame goes when it is blown out. The flame, of course, has not "gone" anywhere: it is simply the process of combustion that has ceased. Removing craving and ignorance is like taking away the oxygen and fuel which a flame needs to burn. The image of the blowing out of the flame, however, should not be taken as suggesting that final nirvana is annihilation: the sources make quite clear that this would be a mistake, as would the conclusion that nirvana is the eternal existence of a personal soul.
The Buddha discouraged speculation about the nature of nirvana and emphasized instead the need to strive for its attainment. Those who asked speculative questions about nirvana he compared to a man wounded by a poisoned arrow who, rather than pulling the arrow out, persists in asking for irrelevant information about the man who fired it, such as his name and clan, how far away he was standing, and so forth (Majjima Nikaya, I, 426). In keeping with this reluctance on the part of the Buddha to elaborate on the question, the early sources describe nirvana in predominantly negative terms such as "the absence of desire," "the extinction of thirst," "blowing out," and "cessation." A smaller number of positive epithets are also found, including "the auspicious," the good," "purity," peace," "truth," and "the furthur shore." Certain passages seem to suggest that nirvana is a transcendent reality which is "unborn, unoriginated, uncreated and unformed" (Udana, 80), but it is difficult to know what interpretation to place upon such formulations. In the last analysis the nature of final nirvana remains an enigma other than to those who experience it. What we can he sure of, however, is that it means the end of suffering and rebirth.
The Fourth Noble Truth, that of the Path or Way (magga; Sanskrit: marga), explains how the transition from samsara to nirvana is to be made.