Krisi, I wasn't aware of this interesting thread. I guess I have some ready, fluid, mental access to your descriptions.
Besides the entire mammalian cerebrum (and certain 'naked neurons' in primitive organisms), the corpus callosum has always caught my attention, especially in many odd cases.
For those who are not yet familiar with the term: the corpus callosum is a bundle of nerves connecting the right and left cerebral hemispheres of the brain. Easily speaking, it normally functions to impart the same amount of information to the two halves of the brain.
Now, in split-brain patients -- as you already know -- there can supposedly be no communication between the left hemisphere (particularly related to speech-controlling) and the non-verbal right cerebral hemisphere. Hence, in such a case, one cannot verbally, laterally express what one feels or thinks. (At times, I can't help but consider my own dyspraxia, or, worse, what seems to be gradual aphasia in the real sense of Wernicke.)
Let's consider the following generic case. It's about how 'rationality may be (apparently entirely) lost while the mind persists on rationality'.
In one experiment (of Broca, if I'm not mistaken) with a split-brained, epileptic patient, different images were shown to the two hemispheres of the brain, which is possible due to the basic fact that the right and left sections of the retina are connected only to the left side and the right side, respectively, of the brain.
The right, non-verbal hemisphere was shown a winter scene. From among four pictorial choices available -- a snow shovel, a chicken, a leaf, and a pen -- the patient's left hand, controlled by the right half of the brain, pointed to a snow shovel. Then, the left, verbal hemisphere was shown a picture of a chicken's claw. The right hand, controlled by the left half of the brain, chose, from among exactly the same four choices, a picture of a chicken.
So, one may conclude that each half of the patient's brain was intelligent. It is somewhat tempting to generalize it further to all brains, of course.
Why did the split-brained patient -- without the corpus callosum functioning -- point to a snow shovel via the verbal (left) hemisphere, which supposedly was not aware of the winter scene sent to the non-verbal (right) hemisphere, but was still aware of the 'non-verbal' hand pointing to the snow shovel? When asked, "Why the snow shovel?" the patient answered, "Just to shovel out the chicken coop." This shows that an association was dodgily manufactured by the verbal (left) hemisphere just to preserve the appearance (emergence) of rationality (causality), although the chicken coop was not previously mentioned at all in the experiment. It appears that it was a pre-cognitive utter fabrication of the patient's mind.
The question, Krisi, is:
"Despite the presence of the corpus callosum, how much of people's (NT's and non-NT's) daily thinking (or every daily modality) involves such spurious mental associations?"
That (from neuroscience) is not all, though. Instead, now let's ramblingly give ourselves some background as to why reality (particularly physical existence) is roughly the way (we think) it is. Actually, essential things of the brain can conveniently be exposed in terms of quantum mechanics (excepting the 'wave function collapse' paradigm and Bohm's formalism of a hidden (deterministic) potential), without the help of neuroscience. That is, without anatomy at all (though verbally it doesn't necessarily mean refraining from mentioning the brain at all).
Let me emphasize that regular cognitive processing operates on an infinitesimal, unitary time scale. Any physical, isolated system evolves unitarily according to the wave equation of quantum mechanics. Thanks to the unitary character of the Hamiltonian in the evolution equation of Schrödinger. That is, the energy-momentum operator transforms unitarily (unimodularly) with respect to infinitesimal coordinate transformations of space and time (translations and rotations). (This is still similar to the Euclidean background of classical, deterministic 'billiard-ball mechanics', it's the embedded processes that are different -- those include fractal neural networks.) Roughly speaking, this is why we are able to be continuously aware of, say, exactly the same spatial event in a given span of time -- that the conscious event is globally invariant. We can be sure that an (ongoing) event now is indeed the same as the same event a few seconds later (to be more precise, a few split seconds later). That, most probably (due to the stochastic nature of quantum mechanics), Krisi now is the same Krisi a few seconds later, with the brain-mind (the prototypical phenomenal mind) converging an ensemble of superposition states (related to Krisi's being-in-existence) in just a couple of seconds. And since, prior to common (objective) observation, there can be many states, especially brain states, of just one entity, Krisi's being-here is no longer single-valued, it (she) is now a canonical multiverse. Schizophrenia exists-in-itself, without the participation of external observers.
Then, it follows from considering just a (temporarily) isolated part of existence (any isolated system, such as the brain), that the entire Universe evolves according to the Schrödinger equation, since it is by definition an isolated system; and so we are aware of the same Universe as long as we exist. That's basically the holographic principle. Let's say, you sleep at night, in this world, and when you wake up the next morning, you almost take it for granted (though rather correctly, as it need not be verified) that you're still experiencing the same world as before.
Upon sense-perception, in just a couple of seconds, (most) phenomenal things (that are otherwise diffusive) get cognitively regularized in the corpus callosum, making sure the brain has a great number of potential directions to the flow of a certain chain of thoughts. (As you already know, normal grown-ups have more amount of white matter in the corpus callosum, which determines their (crystallized) mindsets. And females, since the prenatal stage, are known to have significantly more white matter there than testosterone-laden males. So the majority of girls are supposedly more present, balanced, mature, and predictably regular (neurotypical, non-schizotypal), with respect to both spheres, and to reality. Related to this issue, it is interesting to discover/pinpoint potential differences between a male Aspie and a female Aspie.)
Then, how does something become the content of one's ordinary consciousness?
Well, what if, after all, the brain is just a super-computer -- a universe of automata in itself -- without any operator, with nothing behind it; what if there is just the computer?
Quantum mechanically, the mind (roughly just a mathematical, non-physical, abstract functional (functor), not yet a material brain) perceives all the branches of the wave function associated with a phenomenal event. Only then it freely chooses, before the firing of associated neurons, which branch to focus on. Only then (the notion of) the physical, diamagnetic, cameral brain comes into the picture. Having reflexively received a particular ongoing process from external physical reality, the mind freely chooses from the brain's internal events. This way, the mind plays the role of a puppeteer, and the brain is just like a puppet.
If I were the Universal Programmer, I'd be interested in finding a type of mathematics ('psychogenetic algorithm') for the somatosensoric material brain that would give both order and freedom, increasing complexity (diversity) while avoiding chaos (though not always). Too much order would only systematically determine the whole future of the brain's existence and functioning.
Hence, as a cognitive automaton, the phenomenal mind has no creativity. Creativity requires the presence of cosmic (intrinsic) schizophrenia (a multiverse), other than just the usual reality. Thus, a purely physical, neurological mind (and brain for that matter) cannot possibly undergo (conceive) creativity, for it has 'too much order' in the first place. For this reason, the creative human mind (to me) is necessarily non-physical, as the phenomenal Universe is continuously being self-created (recreated) at every moment (and for seemingly solid objects, it happens through quantum mechanical creation and annihilation of elementary particles).
The mathematical-biological evolution would then allow choices (most especially unique choices) for the thoughts of the mind. From the choices, the mind could freely choose the actions of the physical brain. It is the freely choosing mind, in isomorphic association with the brain's complex neurological arrangements, that makes one conscious.
In quantum mechanics, despite its daily application to particle physics and spintronics (superconductor technology), one may indeed assume (or, rather, perceive) that there are no (material) particles at all; they may exist only as (generally non-conserved) information -- and hence no neurons, axons, synapses, etc., and no brain at all -- and that existence consists solely of the wave function of the non-physical mind. The Universe-in-Itself need not an underlying physical substance (just as the truth of the axioms of geometry (Euclidean and non-Euclidean) does not depend on the existence of solid, material objects at all).
Yet, cognitively knowing this does not necessarily enable one to successfully -- especially mechanistically -- guide one's thoughts, no matter how much one is interested in how things (of the mind and brain) really are. No matter how much one is less concerned about things going one's way as well.
We know that modern neuroscience is not more than 200 years old; it still has little experience and a lot of possibility (most of which is foreseeable by quantum mechanics).
