If this simple example is true, it can be understood that one person lives only in the external world, while another lives in two worlds, and a third person may live in many worlds at the same time. When one asks: Where are those worlds? Are they above the sky, or down below the earth? - the answer is: All these worlds are in the same place as we are. As a poet has said: "The heart of man, if once expanded, becomes larger than all the heavens."