My niece has a theory about ghosts. When the first people came into being, there were no clouds, just clear skies everywhere. Then when the first human being died, a cloud appeared in the sky. When the next one died, another cloud appeared in the sky. Then another, and another. On and on it went, this coming into being and passing away into sky. Sometimes a cloud will miss its former life and return to the earth. We call it a ghost. A whole bunch of them returning at once is called “fog”, which is easier and less scary to say than “a posse of ghosties.” Thank heaven there is also the wind. It moves the ghosties along to where they need to go. And we the living get to enjoy the occasional clear sky, just like they did in the old days.