In the physical world, you are here, and everything else is without you. You are contained in the space. In the dream, all that you see is contained within you. You may dream that you are in Paris, but if you were really in Paris, the Parisians must know that you are there. If they know nothing of it, then you were not in Paris. Paris and everything else in dream, is within you. In that state, you are so great, but you call it dream, an imagination. Imagination is nothing.