David--

Given your emphasis on consulting an author's own commentary, I'm wondering
what your source is for attributing to Clemens the notion that considering a
character's motivations is "mental masturbation."  Since you place that
phrase in quotes, you presumably have a source?  Surely you aren't
speculating?

If he didn't expect readers to consider his characters as representations of
human beings located in particular regions at particular periods in history,
possessing attitudes shaped by their personal and culturally bounded
experiences, what did he expect us to do?

Last, are you suggesting that the only way to read a text is by direction
from the author?   Are you ruling out any meaning that may be derived from
careful research of the cultural context and the language of the text of
which the author may not be fully conscious but may influence his or her
consciousness nevertheless?

--Larry Howe