Joe Quirk and I were editing each other’s books yesterday over his dinner table. I have a passage in mine musing what life might be like if brains could be interconnected the way laptops are today. Joe made all the obligatory noises about the invasiveness of it, the loss of privacy, etc. But then he said, “You know, the only reason we think we’re separate is because our brains can’t exchange much information.”
What’s that mean? The human brain is composed of organs that evolved at different times to do different things, and they often don’t get along. The right brain and the left brain frequently disagree. Split-brain patients — that is, ones who have had the corpus callosum connecting their right and left brains surgically cut — become, in effect, two people sharing space in the same skull. Michael Gazzaniga and Roger Sperry showed that each hand of split-brain patients would follow instructions from the opposite hemisphere regardless of whether the instructions conflicted. (See Pinker, The Blank Slate: The Modern Denial of Human Nature, p. 43.) To use Marvin Minksy’s phrase, the brain is a “society of mind” – a collection of organs that squabble with each other. When the neural connections betwen them are damaged, the truth of their differing agendas — their separateness — emerges.
But in undamaged brains, the conflicts are worked out because the various parts are well-connected. The user — the person, the mind, whatever — feels unified, more or less.
Human beings do exchange a lot of information, of course, but not as much as the subcomponents of each individual brain do. Many neurons in the brain connect to ten thousand other neurons. If, someday, brain implants could let people communicate with that kind of bandwidth, the assumption that human beings are (and should be) separate might diminish, and it might not be missed.
That’s the sort of talk you get when two science writers get together over a kitchen table.