Interesting conversation last night with a Haverford undergraduate seminar group on "Fashioning the Self" that helped me think more about the bipartite brain and its relation to internal experiences, particularly the internal experience of "self identity."
The challenge offered me was the possibility of seeing "all of our our conscious experience as physically grounded and therefore causally determined" and some issues with that - "If our experiences and therefore our identities are tied to our bodies, what happens to our "souls"? How do we explain interpersonal difference? Is faith a creation to assuage the fear of a reducible individuality?"
And the responses I went in with were basically
"I'm inclined to think that "conscious experience" is indeed "physically grounded" but NOT "causally determined," that "interpersonal difference" derives easily enough from physical difference, that "souls"/minds are contained within brains/bodies (a given soul/mind typically exists in varying forms in several brains/bodies rather than being tied to only to a single body/brain), that "faith" is indeed a "creation" (I prefer the term "construction") but that it (like "science," "reality," and other human concepts) originates not in a "fear of a reducible individuality" (individuality in my way of thinking is "emergent" rather than "reducible") but rather as a tool for advancing human exploration of as yet unexperienced possibilities."
Yes, we're in our brains, both consciousness and the experience of self-identity, and there's plenty of physical difference to assure "interpersonal difference." But the architecture of the brain is such that any given function, including a sense of personal identity, is not "causally determined;" there are elements of randomness at various steps in the processing so that a complete knowledge of all inputs and of the system state at any given time would would not suffice to predict the outcome. Hence, material yes, but "reducible" no.
The particularly interesting part of the conversation, for me at least, had to do with the role of choice in personal identity, and in behavior generally. "Elements of randomness" in nervous system function not only make its products "non-reducible" (in the sense just described) but also make it possible for parts of the nervous system ("consciousness" or the story teller) to archive and store several candidate outputs and then choose among them. This in turn provides a foundation for "free will," an ability of the nervous system to exercise some level of control over its own function. An intriguing question that arose is "who" is exercising that control. If one asserts that is being being exercised by a "personal identity" or "self," then one has a homonculus problem, there is a self within the brain that in turn requires explanation. Perhaps a better answer to the question of "who" is exercising self-control is that such exercise is a function of the architecture of the brain generally, and it is because of such exercise that the concept of personal identity is created by the brain, after the fact so to speak. "Personal identity" isn't what makes choices but is instead the brain's way of accounting for the existence of the phenomenon of making choices. And so "personal identity" (along with "free will") is enhanced by increased experience with entertaining possibilities and making choices among them. "I" and "personal identity" are an evolving consequence of making choices rather than that which makes them? One exists and evolves as an individual by virtue of being aware of and choosing among alternatives?
Several years ago, I wrote  "what I originally thought of as the "I-function" I now usually write/talk about as the "story teller" ...
In part, this is to give increased emphasis to the point that the interpretation [of any given arrays of inputs and states] "might in principle always be ... other", ie that there is an arbitrariness, and potentially a creative/discretionary element, inherent in the process that produces what we are aware of. In addition, it has become clear to me that not all awarenesses are centered around "I"; the story may be one not of "self", as it often is for many of us in modern western culture, but can also be about ... communities or other less individualized, egocentric actors ..."
Last night's discussion about who is choosing further strengthens my sense that the "story teller" is a much better term than "I-function" for the internal experience ("conscious") part of brain function. It not only need not be centered on the concept of "I" but ought to be thought of not as the locus of a "self-identity" involved in choosing but rather as an element of choosing that in turn contributes to the elaboration of the concept of self-identity itself.
All this in turn led to the thought that "faith" (in whatever, something outside or inside) can't be "a creation to assuage the fear of a reducible individuality." "Fear of a reducible individuality" is a quite contemporary phenomenon, and "faith," the ability/inclination to accept something not yet shown to be so, is much older. Moreover, the point of the brain's activity is to explore possibilities rather than to achieve definitive answers. From this perspective, "faith" can be thought of not negatively but rather, as William James did, as positive: it opens new directions for exploration.
We didn't actually get in the conversation to one of the starting questions, but my thinking was advanced by having it posed to me in the form it was, and my suggested response to it seems, to me at least, to round out the set of issues on the table in a satisfying way.
"if our experiences and therefore our identities are tied to our bodies, what happens to our 'souls'"?
"a given soul/mind typically exists in varying forms in several brains/bodies rather than being tied to only to a single body/brain"
Perhaps one can think of "soul" as a concept ("construction") created to acknowledge a sense of self-identity that seems indeed to transcend the body in at least two senses interestingly related to one another. One is that other people recognize/acknowledge/relate to it and the other is that it persists after the death of a particular body. I am, of course, not in general the only one involved in my "self-identity," it is to varying degrees co-created with other people and carried and further evolved by them as well as by me, not in identical but in closely related forms. To put it differently, the fact that "self-identity" is material needn't be understood to mean that it ceases to exist with the dissolution of a particular material entity.
I've been reading a wonderful biography of William James recently (William James: In the Maelstrom of American Modernism by Robert Richardson). My suspicion that James is no longer personally involved in evolving his own self identity in no way whatsoever detracts from my appreciation for his continuing existence and the contributions of that to the ongoing evolution of my own. Nor from my strong sense of being a useful participant in the continuing evolution of his.