Q&A: The Questions Raised by Split-Brain Experiments
The Questions Raised by Split-Brain Experiments.
Question
Good afternoon, Rabbi,
Recently I happened to read about the experiments neuroscientists carried out in the 1960s and 70s on epilepsy patients who were treated by cutting the "bridge" that connects brain activity between the right and left sides of the brain. I assume you’ve heard about this as well. In any case, in the experiments the patients continued living their lives as usual, but there was a strange phenomenon: they discovered that each side of the brain has its own character and a kind of independent consciousness. For example, when they ask the patient whether he believes in God, he answers no (the left side is responsible for speech, so the left side is the one answering). But when they show the patient that same question on a sheet of paper in the visual field of the right eye (so that the right side answers by marking yes or no on the page, because again the right side cannot speak), the patient answered yes. There were also cases where patients wanted to put on a certain shirt with one hand and the other hand would throw it away from them.
My question is this: what reckoning does that person receive? It seems as though inside that person there are two consciousnesses with different opinions and different decisions. We can take it even further: does one side of the brain go to heaven and the other side to hell? And in general, what does this whole separation of consciousness mean, and does it contradict the existence of a soul?
(The series of experiments is called the split-brain experiment.)
Answer
I discussed this in detail in my book The Science of Freedom, in the chapter on split-brain experiments. It’s hard for me to go into detail here. In short, the two parts of the brain express different considerations, right-brain and left-brain ones, both of which are valid. A person’s final view is the balancing of all the considerations together and arriving at a conclusion on the basis of all of them. So this does not necessarily mean there are two consciousnesses here. In each of us there are considerations for and against belief, or for and against Republicans or Democrats.
Discussion on Answer
What exactly do you want to be scientifically supported here? This is an interpretation of scientific findings, not a scientific claim.
The Talmud in Sanhedrin gives a parable of a lame man and a blind man: the blind man carried the lame man on his shoulders, and the lame man told him where to turn, and together they stole from the king’s orchard. When the king came, he punished them when they were together. So too, body and soul are rewarded in the future.
Maybe the two parts of the brain, together with the final conclusion, are judged in the future.
Well, if each half-brain carries out a different consideration, as you claim (I’d be glad to know whether that’s scientifically supported), then that would mean that every time we asked each half-brain for its opinion, their views would have to differ from one another, because each of them is carrying out a different consideration. But that isn’t the case… there weren’t always disagreements between the brain hemispheres, so I didn’t really understand your claim.