No shades of gray here—in James's mind, everything is either
black or white. He never said he wasn't an extreme dude.
In this book, white often represents something that is clean
and healthy. The first room James is led to, for example, is so white and
bright that he's inspired to declare: "Everything is white" (1.2.48).
The dentist's office is even "cleaner and whiter" (1.7.209).
Sounds good, right? Of course, part of the rehab process
involves suffering through pain in order to get better, which may be why white
also symbolizes pain, for example when James sees the dentist: "There is
white. Everywhere there is white. There is agony" (1.7.319). In this book,
it's no pain, no gain.
Now, when James gets extra crotchety, he starts talking
about black as though he's a high-school goth kid. "In the terror of my
Addicted mind, all is Black" (2.4.229), he says, trying to convince us
that he's comfortable with this tortured addict persona he has created. He's
proud of it, too: "I like Black goddamnit, and I am going to give it its due"
(2.4.229). This is said without any trace of irony or sarcasm.