"The first time this became even fleetingly obvious to me was at a sesshin, or intensive Zen retreat. On the fourth day there appeared, so to speak, the state of the witness, the transpersonal witness that steadily, calmly, clearly witnesses all arising events, moment to moment. Even in dreaming, one merely witnesses: One can see the dream start, proceed, and end (what Charles Tart has called "translucent dreams"). Roshi, however, was thoroughly unimpressed with all this "makyo." "The witness," he said, "is the last stand of the ego."
"At that point, the whole stance of the witness absolutely disappeared. There was no subject anywhere in the universe; there was no object anywhere in the universe; there was only the universe. Everything was arising moment to moment, and it was arising in me and as me; yet there was no me. It is very important to realize that this was not a loss of faculties but a peak-enhancement of them, it was no blank trance but perfect clarity; not depersonalized but transpersonalized. No personal faculties--language, logic, concepts, motor skills--were lost or impaired. Rather, they all functioned, for the first time, it seemed to me, in radical openness, free from the defenses thrown up by a separate-self sense. This radically open, undefended, and perfectly nondual state was both incredible and profoundly ordinary, so extraordinarily ordinary that it did not even register. There was nobody there to comprehend it, until I fell out of it (I guess about three hours later)."
From "Odyssey: A Personal Inquiry into humanistic and Transpersonal Psychology" by Ken Wilber, printed in The Simple Feeling of Being, page 40.