Who would you say is being separated from whom-the civilized world from the savage world, or the savage world from the civilized world? Why?

In Brave New World, John is alienated
in and exiled from both worlds.  He has no home.

Remember,
there's two kinds of civilizations in Brave New World, the
technological and the primitive, both of which are
dystopias.

Brave New World is a novel
of ideas: it's not about plot or character.  There's no realism in either.  It's a novel
of extremes.  Like Shakespeare's tragic heroes, who cannot live with or without love,
John is a romantic who cannot reconcile either extreme world.  In other words, John
loves them both.  And hates them both.  Through satire, Huxley is saying, therefore, he
(and we) should avoid them both.

John is segregated from
the Brave New World as a child.  He grows up on the Savage Reservation.  He hates it
there.  There's no law, no family, no education.  His mother prostitutes herself, and
John lives in shame.  His problems there are just like the his problems will be in the
Utopia, only without the technology.

John becomes a Byronic
Hero is the Brave New World: he is the misunderstood problem-child of the primitive and
the technological.  At first, the Alphas are mesmerised by his Christ-like virtues.  But
then, after he is corrupted, they abandon him, just like his father did as a child.
 Technology is a red herring, according to Huxley.  It doesn't solve problems: it only
distracts us from them.

So, Huxley is saying that we should
avoid both extremes, both dystopias.  I think he wants his readers to live with a
healthy balance of technology, pleasure, sports, and pharmaceuticals--if that can be
done.  Regardless, we cannot exile ourselves, like John, in either world because it only
leads to tragedy.  We need family, monogamous relationships, education, and religion to
ground us.