According to a dictionary, “Eschatology” is said to be “the part of theology concerned with death, judgment, and the final destiny of the soul and of humankind.” Etymologically eschatology said to be derived from Greek eschatos/eschatē/eschaton meaning “last” and logia “theory/study.” I would like to tentatively define it as a kind of “theory of the final destiny of the world and its inhabitants,” according to any religious or non-religious ideology or philosophy. Some of us might object to using terms such as eschatology in the Buddhist context with the argument the term and concept are alien to Buddhism. I do not necessary buy this argument. If one writes in Sanskrit, Pāli, Tibetan, or Chinese, one might forgo using such terms but as long as we attempt to express in a European language, I think we cannot avoid employing these terms. Sometimes, such terms might even help us to capture Buddhist ideas (for which there is not fixed technical term) in a precise, pregnant, and crystal-clear manner. As far as I am concerned, we do not seem to have, for example, a Sanskrit or Tibetan term for eschatology. Admittedly, utter care should be taken that the terms we employ are clearly defined so as to minimize wrong associations and ambiguities. Needless to state that terms are like the proverbial finger that points to the moon.
There is a Wikipedia entry on “Buddhist eschatology,” which is, however, pretty poor. “Buddhist eschatology” would be like Buddhology. Every Buddhist system or scripture might have its own ideas of eschatology. The challenge is, therefore, how best can we gain a diachronic and synchronic view of Buddhist eschatology. The kind of eschatology that a Buddhist system proposes or presupposes would depend on the theories of cosmology, cosmogony, soteriology, Buddhology, ontology, epistemology, gnoseology, and what I call “Sentientology” (i.e. theory of sentient beings) that that particular system would presuppose or propose. So we will have to first try to trace, examine and determine eschatological ideas found in the most conservative form of Buddhism and then study how these ideas have developed. This is obviously not an easy task.
Here are some avenues of exploration: (a) What are the ideas of evolution and devolution (and dissolution) of the external and internal world? (b) What forces sustain external and internal world? (c) Can one speak of an individual or personal eschatology and a universal eschatology in Buddhism? (d) Where do the Buddha and his teaching (or more so their disappearance from the world) fit into the broader picture of Buddhist eschatology? (e) How absolute are the Buddhist eschatological ideas? (f) Is an absolute end of the world and its inhabitants at all possible? Is nirvāṇa the eschatological absolute (LS 1969: 159, referring to de la Vallée Poussin)? If so, is nirvāṇa possible on a universal scale, or is it possible only on a personal level? What about the ideas that buddhas never pass away, and dharma would never disappear? Is emptying of saṃsāra possible? What about sems can gsar skye?