We're each two different people, is why, and we live in two different worlds. Just as we carry our waking bodies and some of our waking thoughts into the world of dreams, so we bring the thoughts and happenings of the world of dreams back with us when we return to the world of daylight. They mingle, they explain each other: we look forward and backward, trying to find a reason for what is happening in this world by remembering something more or less like it that happened in the other. The mix-up comes when we stand between the two, groping in both directions.