There are certain intervals of consciousness between two thoughts--such as those between waking and sleep and those between sleep and waking--which normally pass unobserved because of the rapidity and brevity associated with them. Between one moment and another there is the timeless consciousness; between one thought and another there is a thought-free consciousness. It is upon this fact that a certain exercise was included in The Wisdom of the Overself which had not previously been published in any Western book. But it is not a modern discovery. It was known to the ancient Egyptians, it was known to the Tibetan occultists, and in modern times it was probably known to Krishnamurti. The Egyptians, preoccupied as they were with the subject of death and the next world, based their celebrated Book of the Dead upon it. The Tibetan Book of the Dead contained the same theme. Between the passing out of the invisible vital-forces body at the end of each incarnation and its entry into that state of consciousness which is death, the same interval reappears. If the dying man can lift himself up to it, seize upon it, and not let it escape him, he will then enter into heaven--the true heaven. And it was to remind him of this fact and to help him achieve this feat that the ancient priests attended his last moments and chanted the pertinent passages from these books. This mysterious interval makes its appearance throughout life and even at death, and yet men notice it not and miss an opportunity. It happens not only at the entry into death but also in between two breaths. It is possible to go even further and say that the interval reappears for a longer period between two incarnations for there is then the blocking out of all impressions of the past prior to taking on a new body. Plato must have known it.
-- Notebooks Category 23: Advanced Contemplation > Chapter 6: Advanced Meditation > # 81