In Buddhism, we have the fundamental concept called "Samadhi," which suggests the state of Buddhist enlightenment. But before the 20th Century it was not so clear what was the real contents of Samadhi. But in the 20th Century because of the enormous development of mental and physical sciences, the scientific knowledge has grasped that "The Buddhist Samadhi is just the balanced state of the Autonomic Nervous System."
As in my first Buddhist Book in Japanese, which is entitled "Bukkyo : Daisan no Sekaikan, or Buddhism : the Ultinate World View," I have insisted that "The Buddhist Samadhi is just the balanced state of the Autonomic Nervous System." But at that time such an insistence has been only a kind of hypothesis, therefore it was not so relyable, but since then the time has been past for 50 years, and during that time there were so many affirmative scientific researches that the state of human body and mind in Zazen practice have been governed by the balanced state of ANS. And such kind of scientific researches have been continuing even today, and so I think that when we research the fundamental basis of Samadhi, we can suppose that it might become much more clear that the balanced state of our body and mind in Zazen might be the balanced state of human Autonomic Nervous System decisively.
Therefore I think that the scientific researches of Zazen practice has arrived at its ultimate conclusion in the 20th Century. Human beings have found that the Samadhi in Buddhist practice is inevitably the balanced Autonomic Nervous System of Human body and mind absolutely. And if someone would doubt this conclusion, he can never understand the total philosophical system of Budhism at all. Therefore we can think that the Gautama Buddha's buddhist philosophy has changed from some kind of religion, which has been relying upon a religious belief, into the philosophy, which has been interpreted in the 20th Century, and the meaning of words that Buddhism has changed from religion into philosophy, because the Buddhist religious system has become philosophy, relying upon the facts that the religious charactoristic of Buddhism, which has been believed relying upon religious belief, has arrived at the theoretical conclusion, which has been solved by the theory of the Autonomic Nervous System.
Therefore we can think that Buddhism has become from religion to philosophy at last. Without the theory of ANS, the theory of Buddhism can never be the ultimate philosophy, but relying upon the theory of ANS, Buddhism can become the ultimate philosophy, because the total theory of Buddhism can become the very exact theoretical system, which can be understood by the theory of SNS, PNS, and the balance of ANS. Therefore we can think that Buddhism has become the ultimate philosophy of Realism, which can be interpreted as the present Action of human being, or the whole Universe itself, or all Buddhist theoretical system on the basis of Human Action, or the Reality itself at the present moment.