 The concept of a world in the MWI is based on the layman’s conception of a world; however, several features are different. Obviously, the definition of the world as everything that exists does not hold in the MWI. “Everything that exists” is the Universe, and there is only one Universe. The Universe incorporates many worlds similar to the one the layman is familiar with. A layman believes that our present world has a unique past and future. According to the MWI, a world defined at some moment of time corresponds to a unique world at a time in the past, but to a multitude of worlds at a time in the future.