Is Buddhism exclusivistic? This question has been puzzling me for some time... So many sutras speak of their self-contained teachings to be the "highest" or "greatest" -- essentially surefire ways to attain enlightenment.
The Buddha himself rejected the other schools as they existed in his time (most relevant is the Jains who aimed for the same goal of cessation of rebirth). If he thought their methods were effective he would have adopted them, but he did not. He rejected them.
To what extent is the notion that there are "84,000 [distinct] ways to the dharma" true? Does this mean that, say, Christianity or Islam or Hinduism are in their own ways one of the 84,000? Do people, regardless of religious affiliation, become pratekyabuddhas or buddhas in their own right?
Christianity and Islam do not have any concept of saṃsāra. The whole goal of both programs is to achieve birth in a postmortem paradise on the good grace of an omnipotent deity. They have no concept of saṃsāra, let alone liberation from it. Various schools classified as Hinduism have an idea of saṃsāra and aim towards liberation from it, though it seems improbable from a Buddhist perspective given their widespread emphasis on ātman
, which constitutes a wrong view which hinders liberation. At best they achieve rebirth in a form or formless realm.
It would seem that enlightenment simply means the full comprehension and experience of no-self and emptiness. Is this limited to Buddhist meditations such as Vipassana or Samatha... or is it the case that when, say, Christian mystics like Eckhart and Joseph the Hesychast engaged in contemplative prayer aiming for "spiritual silence in God" they were close to experiencing something similar to sunyata?
In terms of the earliest Buddhist literature it seems the Buddha himself promoted his meditation system of the dhyānas as the main process by which one could be liberated. It was not a matter of immobilizing the body and mind like the early Jains promoted, but having appropriate mental stamina coupled with right view. Some later people suggested the dhyānas are mundane accomplishments and do not strictly result in liberation; it actually being the wisdom fostered through right view and actualized through dhyāna itself that would result in liberation. From that perspective even mastery of dhyānas is insufficient. One must have right view.
There is one theory that pratyekabuddhas achieve liberation by themselves by recollecting the teachings of past Buddhas. Being well cultivated in their meditative practices already they have only to gain right view to quickly proceed towards ultimate liberation.
Christians possess wrong view and have no sense of saṃsāra to begin with, so how could they achieve liberation? Moreover, emptiness is the idea of dependent origination -- causality where all things arise due to causes and conditions. Monotheists reject this by suggesting all of time and space is traced to the act of Creation by a sole omnipotent god.