Buddhism grew up in the context of Hinduism, but as it spread to lands outside that territory, it saw a corresponding decrease in popularity within India itself. It was as if it was granted residence there only so long as it took for it to stand and walk away, and this is why it’s appearance and disappearance should be seen, for India, as but a historical episode. It is wrong, then, to mark out some sort of dividing line between pre- and post-Buddhist Hinduism, as if that doctrine permanently altered the tradition which fostered it. This being that case, we should inquire into the true significance of Buddhism. If it was not a heresy to be rejected, and yet not a re-adaptation of Hindu doctrine to be embraced by it and allowed to supersede it, then what was it? If we take into account its susceptibility to re-adaptation, of which Zen Buddhism is an excellent example, it would not be far from the truth to suggest that while it was necessary for Buddhism to have its roots in Hinduism, it was never made for Hinduism, but was rather a mobilized re-adaptation capable of carrying its doctrine across the face of the Earth. By analogy, taking into account the necessary differences between the religious and non-religious contexts, we can say that Buddhism was to Hinduism what Christianity was for Judaism; for Judaism, by its nature, was never capable of being adopted elsewhere while Christianity is much more susceptible to application in various contexts.
Buddhism’s various adaptations in the Middle and Far East, namely Zen and Tibetan Lamaism, will be discussed when the Buddhist doctrines are taken up as a special subject.