Q&A: Split Brain, Split Soul?
Split Brain, Split Soul?
Question
Hello Rabbi,
I listened to your lecture from the series on free choice. I have a question about your analysis of split-brain syndrome. This syndrome seriously undermines the idea of free choice.
I adapted your diagram of the libertarian position to the case of a split brain.
Let’s take the experiment in which they show:
- to the right hemisphere — a picture of a snowy roof, which the subject associates with a picture of a snow shovel.
- to the left hemisphere — a picture of a chicken leg, which the subject associates with a picture of a chicken head.
The subject cannot explain why he chose the shovel, and says that the shovel is meant for cleaning out the chicken coop.
If your diagram is correct, then at stage 3 the soul receives the information of the picture of the snowy roof.
Why can’t the soul transfer that information to the brain’s left hemisphere?
Why can’t the soul force the left hemisphere to say:
\"I chose the shovel because I saw a snowy roof\"?
Answer
I have no idea how the connection between the soul and the brain works. But you don’t need to get to this special case. In any brain injury, you could ask why the soul doesn’t use another part of the brain to handle the matter instead of the damaged part. The fact is that the different functions are carried out דווקא in specific parts of the brain, meaning that there is a functional division of the brain’s roles among its parts. What you are really wondering about is precisely that itself: why shouldn’t the soul do whatever it wants in whichever part of the brain it chooses, or even without the brain at all.
Discussion on Answer
Honorable Rabbi Michi, I think my question is more subtle. I understand that there are cases of brain injury:
At stage 2: the information transmitted to the brain is incorrect. For example John Nash (in the movie), who sees imaginary people.
At stage 3: the soul decides something, but the instrument (the brain) does not function properly.
But in my question, the brain is functioning properly. There is only a problem in transferring information between the hemispheres. As a libertarian, you need to say that the soul has the correct information (for if it didn’t, on what basis would it decide?) through the right hemisphere — that is, that the person saw the snowy roof — and you also need to say that that same soul decided to say (through the left hemisphere), “I chose the shovel because it was meant to clean out a chicken coop.”
My question: why didn’t the soul decide to say, “I chose the shovel because I saw a snowy roof”?
I wrote that I do not know exactly how the connection between the soul and the brain is conducted. It is certainly possible that the linking between the data in the world is also done by the soul through the brain. You assume that in your diagram the soul at the center is also what makes the connections between the pieces of data and the interpretation of the whole picture. But it may be that this too is done through the brain.
In another way, which seems less likely to me, the problem could also be on the right side of the diagram — that is, in the output. The soul is unable to explain to another person the picture it has (correctly and in full), since the act of explanation itself is done through the brain.
You’re dodging the fact that the soul is not local, and the proof is that each side on its own functions well.
That means 2A and also 2B function properly.
And therefore we would expect, at the very least, some difference between making a decision and stating an explanation.