"The sages became absorbed in the discovery that as concentration deepens, the mind actually passes through the states of consciousness being inquired about. And in concentrating on consciousness itself - "Who is the knower?" ...If Freud's limited glimpses of the unconscious can have had such an impact on civilization, the sages who mapped the mind three thousand years earlier must rank with the greatest explorers in history....In dreaming, the Upanishad observes, we leave one world and enter another. " In that dream world there are no chariots, no animals to draw them, no roads to ride on, but one makes chariots and animals and roads oneself from the impressions of past experience." " Eknath Easwaran from 'The Upanishads'