Martin writes against caste discrimination:

As far as I know, the way of thinking that we
find in the castsystem is something very
human. In every culture you find Gods, humans
that are close to that Gods and kind of
slaves, that do the work. The cast system is
just a manifestation of that. But to make it
that rigid like this castsystem, is obviously
oldfashioned. But traditotional values can't
be pushed away easily