Buddhist and non-Buddhist religions, lay stress on scriptural authority, that is holy books, writings, and doctrine. But Zen denounces all this on the grounds that words or characters can never adequately express religious truth, which can only be realized from within. Consequently Zen claims that the Enlightenment of Buddha has been handed down neither by word of mouth, nor by the letters of scriptures, but from teacher's heart to disciple's heart, through a line of personal transmission until the present day. Zen is an isolated instance of this heart-to-heart transmission in the whole history of the worlds religions. by Kaiten Nukariya, The Religion of the Samurai.