It's generally seen as a form of relativism, but that's an unfair way to write off James's philosophy. James also invented psychology, making him a badass and worthy of reading.
I just had this suggested to me. It sounded compelling enough that I put in an order on amazon. Reading the Google BOok preview. To those interested in philosophy of consciousness, this is basically a critique of the neuroscientific view of consciousness as something "inside" the brain
If it revolves around qualia, I'm not interested. The physicalist above all else wants to make the following claims:
1) Conscious mental states are realized by brain states. 2) A particular conscious mental state exists only if a particular brain state exists.
It is difficult for a philosopher to give a complete account of the mind without hypothesizing far beyond these two claims. Opponents of physicalism, usually motivated by traditional dualist inklings, attack the weakest of these further claims and provide these weaknesses as proof against physicalism.
However, I do not believe in magic. Our minds are very clearly the product of our brains. To deny this is to affirm some sort of hocus pocus mental substance that exists independently of matter and the laws of physics.
I can affirm that it isn't asserting any kind of mystical bull**** about a soul or something. I would not bother reading it if it was. It was suggested to me proxy an Objectivist mailing list, by Harry Binswanger who gave a pretty long review of it.
It takes only a bit of technical knowledge on the brain, one you might have even gleamed from philosophy, to understand the book. A portion of it is available on google books which will probably give you a good understanding of the book's thrust.
Actually, I find nothing objectionable about that thesis. It sounds like he's saying consciousness arises not just from the brain itself, but from the operation of the system consisting of (at least) the brain and its perceptual inputs. That's an important technical point, but it does not change the central theses of physicalism, which denies any non-physical explanation of the mind. I do have reservations about his claim that "the world" is an important part of this system that excludes components outside the brain. I'm not sure what he means by that, but I think it's well-established that our conscious minds do not have direct experiential access to the world and one can trigger conscious experiences without their conventional external correlates.
Anyway, the book doesn't sound as bad as I thought. I was thinking you were reading something by a Chalmers-ish philosopher.