Every time a quantum event takes place the universe splits so that all possible outcomes occur but in different universes. With each split whole entire universes are created and in each of these universes is a copy of ourselves, but they are not ordinary copies for they are actually us. It is after this split that differences begin to occur for then each world is on its own, though with an identical past. The many universes theory tells us that there can be no physical contact between the split universes, however because our doppelg ngers inhabit these other worlds we have no need to make physical contact - we are in a sense already there. Visiting ourselves in other worlds When our minds are unlinked from this world in sleep, the way is open for us to experience the other universes through our doppelg ngers.
Dreams are the result.
Like with splitting universes there is no actual cataclysmic sense of being ripped asunder when moving from one world to another. If we visit 10,000 worlds per earth second our doppelg ngers in those 10,000 worlds may not perceive the same thoughts or sensations we perceive. Our stay in any one world may not be long enough for us to experience events in the same context in which our doppelg ngers experience these events. One indication that we are moving from one world to another is the difficulty encountered in reading a piece of text in a dream. Even with the force of will available in lucid dreams it is nearly impossible to stabilize the image and stop the words from changing at every blink of the eye or even before your eyes.