If you say, There was nobody on the bus, or, I had the bus to myself, or as now, The bus was empty, nobody thinks spirits were driving. At a play rehearsal, you can notice that the theater is empty. Sometimes people leave a party because there's nobody there. When the housekeeper answers your knock, if her employer's away, she may say, Nobody's home. Nobody doesn't mean no body.
Empty space is empty like that.
Empty fields are empty like that. Columbus discovered that kind on uninhabited land. But the bus was also empty in the way only buses can be empty. Every new world is empty because we who are us haven't discovered ourselves in it yet. A house can be empty the way a body can be, because no one's ever really at home inside.