There are at least two things you should know about William James’s philosophical views. The first concerns his so-called “thoroughgoing dualism” in the Principles of Psychology. At times James is an epistemological dualist, with the aim of psychology to explain the cognitive relation between a knower and what it knows. But at other times James appears to be a metaphysical dualist, with psychology aiming to explain the causal relation between physical things and mental (brain) states. The Stream of Thought chapter from the Principles, the best example of how contrary James’s observations of consciousness run against positivism, makes much more sense in the context of epistemological, and not metaphysical, dualism. To understand the Principles you need to understand how psychology-as-epistemology differs from psychology-as-metaphysics.
Secondly, does James regard psychology as an exclusively “person-centered” science? Now it’s only in maybe the past fifty years that philosophers began to widen their view of consciousness beyond its purely “cognitive” content by recognizing emotions, desires, etc. James, quite purposely I think, blurred the usual distinctions between thoughts and feelings, so that we might not identify “thought” solely with the cognitive, or “feeling” with the noncognitive, aspects of conscious awareness. We have cognitive feelings, too – feelings of ‘if,’ of ‘and,’ of ‘with’ – not unlike our sensory awareness of, say, a patch of blue. So it’s important to not misconstrue James’s term “feeling” in an exclusively emotive way. Consider what sort of notion of person is at work in the Principles. Clearly, any adequate science must be “subjective” or “personal” to believe in its hypotheses, at least enough if for no other reason than to be able to test them. But to what extent? The “cure,” if you will, is not simply to give ourselves over to the subjective pole of experience once and for all, but to provide an account that accommodates both subject and object poles of experience. James’s radical empiricism sets out to do precisely this. If the intent of a “person-centered” science is only to discard one pole of experience for the other, then it makes the same mistake positivism makes – just in the opposite direction.