Gospel of Immortality
The Buddha preached the Gospel of Immortality to the world for forty long years. The mortal body, which was depersonalized by the Bodhisatta, in the process of waking up to Buddhahood, was visible to the public, as the body of the Buddha, and the public identified the Buddha with it. Though this body was not Buddha strictly, the Buddha appeared to the world, through this body, and preached the Gospel. When this mortal body died, however, no one could identify the Buddha as before. The Buddha seemed to disappear from the world, when this so called body of the Buddha died, even though the Buddha was still visible to one who saw the Dhamma.
This apparent disappearance of the Buddha is called, Parinirvana, meaning “Complete Nirvana,” by Theravada Buddhists today. This term, however, is misleading because it implies that the “Nirvana” that the Bodhisatta achieved at the time of “waking” was incomplete. A more meaningful term is “Anupadisesa Nirvana,” which means, Nirvana without the depersonalized remains. In contrast, the Nirvana at the time of “waking” is called “Sopadisesa Nirvana,” which means, Nirvana with the depersonalized remains. This usage of terms is preferable to the use of the term Parinirvana as “Complete Nirvana.”
Even this usage of terms Sopadisesa and Anupadisesa is strictly speaking incorrect because in the Itivuttaka the Buddha points out that these terms mean something else. According to this Sutta the Sopadisesa and Anupadisesa are experiences to be realized here and now, instead of one being something to be experienced in this life and the other to be experienced after death. Sopadisesa is the experience of the Arahat in the normal life, for example, when going on pindapata or when communicating with others. Anupadisesa is the experience of the Arahat when experiencing Nirodha Samapatti.
The Bodhisatta “ceased to be” in becoming a Buddha, but once a Buddha, He is really “absent.” We use the higher “H” to indicate that He has transcended the “self-centered existence,” and He does not exist as a “self” any more. This is because the Buddha is not an entity, or body, or even a mind or a soul and He has no identity, no personality; “He” never “is,” nor “was,” nor “will be.” If so, how could “He die?” Therefore, Parinirvana is not a glorified term for “death.” It is the complete cessation of “being,” which occurred when the Bodhisatta became a Buddha.