How does symbolism establish the theme or conflict in "By the Waters of Babylon?"

I am not actually sure that symbolism has much to do with
establishing the theme of this short story - far more valid and important to working out
the theme is the setting, so in my response I will focus on
this.

This masterful dystopian short story is used a lot in
English teaching to give an excellent example of 1st person narration, where a character
is telling you the story directly, and you can only see the action through their eyes,
contrasted with an omniscient narrator who is god-like and all-seeing and can tell the
reader what every character is thinking and feeling. This form of limited narration is
used to great effect by the author as we literally go on the journey with John, seeing
and feeling what he sees and feels, and we gradually piece together like a jigsaw puzzle
what is going on, where we are and what has happened.

This
narrative technique greatly serves to emphasise the message or theme of this story. We
slowly begin to work out the many clues that there are (such as the names John gives
things like "god roads" and what the sign "ASHING" rally said) and realise that this
story is set in a post-nuclear war world which has been decimated, and the inhabitants
have sunk back into the dark ages. John and his tribe describe a primitive world with
many threats and mysteries that they do not fully understand. However, during the course
of his journey and the vision that he has in "the high towers of the gods" John reflects
the moral of the story: "Perhaps, in the old days, they ate knowledge too
fast."

This then is the brutal warning that the story
gives: we live in an era of unprecedented scientific discovery, yet we risk discovering
too much truth too quickly, and opening some terrible Pandora's Box or using scientific
advances before we fully understand their consequences. One only has to look at the
press today and issues such as stem cell research, the human genome research project and
cloning to see that the danger is still here and Benet's short story is still just as
applicable in today's society. Whether we take heed or not is another
matter...

Thus it is the setting far more than the
symbolism that to my mind plays a vital part in establishing the disturbing theme of
this story. Whilst of course there are examples of symbolism, these are secondary when
it comes to the theme.