Survival and Myth
In the story By The Waters of Babylon there were a lot of references to myth and survival.  John's father told him quite often about the gods and what he should do to please them.  Never to go to the God's temple becuase it was forbidden.  Never to go to the god's road because it was forbidden.  John's father and himself were faced by one common idea,  Man against Myth.  Some of the common myths in human history are set in place for simple reasons.  Sometimes to keep others out and to keep curiousity away.