http://faculty.washington.edu/smcohen/320/cave.htm
*** If you have not seen the new film, do not read below as I speculate on some plot themes. ***
I think most of you will know what I speak of (The Republic by Plato).
That, to me, seems to be the theme of The Matrix (parts 1 and 2). The Cave is the Matrix and prisoners are the "plugged in" humans. (Though after seeing the second movie, I'm wondering if even the unplugged people aren't plugged in) Also from this it is easy to draw a conclusion about what Matrix: Reloaded was all about and what's real and what's precieved to be a shadow of the real.
Perhaps the "Real World" of The Matrix is a shadow of a true world, but we are only looking at a shadow of a n dimensional world in (n-1) dimensions. Therefore the "Real" is just an distorted manifestation of the "True Real".