What is the relationship between Enlightenment and Nirvana? How did Buddhists come to realise Arhatship? What convinced them of their attainment? Is the Enlightenment of an Arhat the same as that of the Buddha? To answer these questions and many others in close connection with them was the task imposed upon various schools of Hinayana and Mahayana Buddhism. While they quarrelled much, they never forgot that they were all Buddhists and whatever interpretations they gave to these problems they were faithful to their Buddhist experience. They were firmly attached to the founder of their religion and only wished to get thoroughly intimate with the faith and teaching as were first promulgated by the Buddha. Some of them were naturally more conservative and wished to submit to the orthodox and traditional way of understanding the Dharma; but there were others as in every field of human life, whose inner experience meant more to them, and to harmonise this with the traditional authority they resorted to metaphysics to its fullest extent. Their efforts, there is no doubt, were honest and sincere, and when they thought they solved the difficulties or contradictions they were satisfied inwardly as well as intellectually. In fact they had no other means of egress from the spiritual impasse in which they found themselves through the natural and inevitable growth of their inmost life. This was the way Buddhism had to develop if it ever had in it any life to grow. While Enlightenment and Nirvana were closely related to the conception of Buddhahood itself, there was another idea of great importance to the development of Buddhism, which however had no direct connection apparently, though not in its ultimate signification, with the personality of the Buddha. This idea naturally proved to be most fruitful in the history of Buddhist dogmatics along with the doctrines of Enlightenment and Nirvana. I mean by this the doctrine of non-Atman which denies the existence of an ego-substance in our psychic life. When the notion of Atman was ruling Indian minds, it was a bold announcement on the part of the Buddha to regard it as the source of ignorance and transmigration. The theory of Origination (_pratītya-samutpāda_) which seems to make up the foundation of the Buddha’s teaching is thus finally resolved into the finding of a mischievous “designer” who works behind all our spiritual restlessness. Whatever interpretation was given to the doctrine of non-Atman in the early days of Buddhism, the idea came to be extended over to things inanimate as well. Not only there was no ego-substance behind our mental life, but there was no ego in the physical world, which meant that we could not separate in reality acting from actor, force from mass, or life from its manifestations. As far as thinking goes, we can establish these two pairs of conception as limiting each other, but in the actuality of things they must all be one, as we cannot impose