When attention thus centres in the person of the Buddha as the author of the Dharma, the question of his inner experience known as Enlightenment becomes the most vital one. Without this experience the Buddha could not be called a Buddha; in fact, the term “Buddha,” the Enlightened One, was his own making. If a man understands what enlightenment is or really experiences it in himself, he knows the whole secret of the Buddha’s superhuman nature and with it the riddle of life and the world. The essence of Buddhism must then lie in the Doctrine of Perfect Enlightenment. In the enlightened mind of the Buddha there were many things which he did not and could not divulge to his disciples. When he refused to answer metaphysical questions, it was not because the minds of the questioners were not developed enough to comprehend the full implications of them. If however the Buddhists really desired to know their master, and his teaching, they had to study the secrets of Enlightenment. As they had no living master now they had to solve the problems by themselves if they could, and they were never tired of exhausting their intellectual ingenuity on them. Various theories were then advanced, and Buddhism grew richer in content, it came to reflect something eternally valid besides mere personal teaching of an individual. It ceased to be a thing merely historical, but a system ever living, growing, and energy-imparting. Various Mahayana Sutras and Shastras were produced to develop various aspects of the content of Enlightenment as realised by the Buddha. Some of them were speculative, others mystical, and still others ethical and practical. In the idea of Enlightenment was thus focussed all Buddhist thought. Nirvana as the ideal of Buddhist life next engaged the serious attention of Buddhist philosophers. Was it an annihilation of existence, or that of passions or desires, or the dispelling of ignorance, or a state of egolessness? Did the Buddha really enter into a state of utter extinction leaving all sentient beings to their own fate? Did the love he showed to his followers vanish with his passing? Would he not come back among them in order to guide them, to enlighten them, to listen to their spiritual anguish? The value of such a grand personality as the Buddha could not perish with his physical existence, it ought to remain with us for ever as a thing of eternal validity. How could this notion be reconciled with the annihilation theory of Nirvana so prevalent among the personal disciples of the Buddha? When history conflicts with our idea of value, can it not be interpreted to the satisfaction of our religious yearnings? What is the objective authority of “facts” if not supported by an inwardly grounded authority? Varieties of interpretation are then set forth in the Mahayana texts as to the implications of Nirvana and other cognate conceptions to be found in the “original” teaching of the Buddha.[f24]