I have a hard time squaring this with split brain research and alien hand syndrome.
For those who are not aware of this research it involves the severing (either because of disease or on purpose to treat disease) of the communication pathway between the two hemispheres of the brain. Reportedly, the symptoms are profound in some patients. What occurs in some patients is reportedly nothing less than the splitting of the mind into two separate entities with each mind controlling distinct portions of the body and its resources. The two minds can reportedly be at cross purposes.
Problems of an even more severe nature have plagued patients following complete (surgical) destruction of the corpus callosum and thus the neural pathways linking the two medial motor areas of the frontal lobes (Joseph, 1988ab). These independent "alien" behaviors usually involve the left hand and the half of the body, and were purposeful, intentional, complex and obviously directed by an awareness maintained by the disconnected right hemisphere (which controls the left hand). These alien actions were often completely against the "will" of the consciousness maintained in the left hemisphere.
These "alien" disturbances were so purposeful, and often so well thought out, it was as if these "split-brain" patients had developed two independent "free wills" maintained by independent minds housed in the right and left half of the brain (Joseph, 1986b, 1988a,b); two free wills and two minds which were unable to communicate, and each of which had a "mind of its own."
As originally described by Nobel Lauriate Roger Sperry (1966, p. 299), "Everything we have seen indicates that the surgery has left these people with two separate minds, that is, two separate spheres of consciousness. What is experienced in the right hemisphere seems to lie entirely outside the realm of awareness of the left hemisphere. This mental division has been demonstrated in regard to perception, cognition, volition, learning and memory."
For example, one patient's left hand would not allow him to smoke and would pluck lit cigarrettes from his mouth. He reported that he had been trying to quit, unsuccessfully, for years, but it was only after the surgery that he found he couldn't smoke, because the left hand wouldn't let him (Joseph, 1988a).
Link for the above.
Reading more from the link above and you'll see that other examples include a patient who could not get dressed because, "she would be putting on clothes with her right and pulling them off with her left." Another divorced man literally had one half of his body pulling him to reunite with his ex and the other half refusing. The examples go on and on and are quite compelling. For instance, there is even reports of one person with two minds of a different persuasion when it comes to the question of faith in god:
Two minds in the same body... one is atheist and the other theist
I find these accounts, if true and valid, to be a clear challenge to the idea that the mind and brain are substantively different. If physically splitting one necessarily splits the other, isn't this evidence that the two are of the same 'substance'?
Moreover, in Buddhism we are taught that the mind is one continuous stream. I've never heard that this stream can be divided into two. Which stream would inherit which karma? It seems to me that split brain research, if true and valid, presents a real challenge to the Buddhist conception of the mind and brain and the differences between the two.
You'll probably note that I've qualified this research a few times and I do so because I am aware that there is some contention about whether this research really is true and valid. However, while I am certainly interested to hear more about this contention and think it worthwhile to discuss whether this research is valid I am hoping that this thread will assume for the sake of argument that it is valid and that the examples above are true. Given this assumption, are my questions and qualms a necessary reaction or is there any way to square this research with the Buddhist conception of mind and brain?
I'd love to hear opinions. Thanks!