Question Marks

[barleydog at earthlink.net]

Does anyone have an idea what we are to make of the frequent question
marks at the ends of dialogues that are not interrogative in M & D? It's
kind of unsettling.  But maybe that's exactly the point!  Is Pynchon
trying to convey a certain tone of voice, or something about the
character (I believe they mostly occur when M or D are speaking.

Any ideas/help would be appreciated.

David