The waking self is a nexus of motives and orientations which belong as much to the system of its world as to that of its self. That you can so easily slip into dreaming when the tension is relaxed and the weave loosened shows how fragile and contingent this apparent continuity is. It is as if other stories are going on in hundreds of adjacent rooms and you suddenly open your eyes in a different one without any sense of disjunction, there is no pop, but there you are in the middle of a different tale, with a different world about you just as familiar as this one. The point is how easy the transition is made - the same self contains each world as naturally as any other - what makes it yours has nothing to do with the ongoing story. As if what is you is something like a tape-head regardless of what tape it happens to be reading. The stories differ only in their qualities of realism, in the degree to which they can convince the dreamed protagonist that where he finds himself is the only world, the reference world against which all others are to be measured, the power of its metaphors for dreaming. Everything is subject to fiction, that is what you learn from fiction, without ever quite believing it.