Well, the young man agreed with the concept and looked forward to its execution. And a mere month after he had first heard the thing proposed to him, his brain was floating in the warm nutrient bath. His scientist friends kept busy researching, by means of paid subjects, which patterns of neuron firings were like the natural neural responses to very pleasant situations; and, through the use of a complex electrode machine, they kept inducing only these neural activities in their dear friend’s brain.
Then there was trouble. One night the watchman had been drinking, and, tipsily wandering into the room where the bath lay, he careened forward so his right arm entered the bath and actually split the poor brain into its two hemispheres.
The brain’s scientist friends were very upset the next morning. They had been all ready to feed into the brain a marvelous new batch of experiences whose neural patterns they had just recently discovered.
“If we let our friend’s brain mend after bringing the parted hemispheres together,” said Fred, “we must wait a good two months before it will be healed well enough so that we can get the fun of feeding him these new experiences. Of course, he won’t know about the waiting; but we sure will! And unfortunately, as we all know, two separated halves of a brain can’t entertain the same neural patterns that they can when they’re together. For all those impulses which cross from one hemisphere to another during a whole-brain experience just can’t make it across the gap that has been opened between them.”
The end of this speech gave someone else an idea. Why not do the following? Develop tiny electrochemical wires whose ends could be fitted to the synapses of neurons to receive or discharge their neural impulses. These wires could then be strung from each neuron whose connection had been broken in the split to that neuron of the other hemisphere to which it had formerly been connected. “In this way,” finished Bert, the proposer of this idea, “all those impulses that were supposed to cross over from one hemisphere to the other could do just that—carried over the wires.”
This suggestion was greeted with enthusiasm, since the construction of the wire system, it was felt, could easily be completed within a week. But one grave fellow named Cassander had worries. “We all agree that our friend has been having the experiences we’ve tried to give him. That is, we all accept in some form or other the neural theory of experience. Now, according to this theory as we all accept it, it is quite permissible to alter as one likes the context of a functioning brain, just so long as one maintains the pattern of its activity. We might look at what we’re saying this way. There are various conditions that make for the usual having of an experience—an experience, for instance, like that pond-hole experience we believe we gave our friend three weeks ago. Usually these conditions are the brain being in an actual body on an actual pond stimulated to such neural activity as we did indeed give our friend. We gave our friend the neural activity without those other conditions of its context because our friend has no body and because we believe that what is essential and decisive for the existence and character of an experience anyway is not such context but rather only the neural activity that it can stimulate. The contextual conditions, we believe, are truly inessential to the bare fact of a man having an experience—even if they are essential conditions in the normal having of that experience. If one has the wherewithal, as we do, to get around the normal necessity of these external conditions of an experience of a pond hole, then such conditions are no longer necessary. And this demonstrates that within our concept of experience they never were necessary in principle to the bare fact of having the experience.
“Now, what you men are proposing to do with these wires amounts to regarding as inessential just one more normal condition of our friend’s having his experience. That is, you are saying something like what I just said about the context of neural activity—but you’re saying it about the condition of the proximity of the hemispheres of the brain to one another. You’re saying that the two hemispheres being attached to one another in the whole-brain experiences may be necessary to the coming about of those experiences in the usual case, but if one can get around a breach of this proximity in some, indeed, unusual case, as you fellows would with your wires, there’d still be brought about just the same bare fact of the same experience being had! You’re saying that proximity isn’t a necessary condition to this bare fact of an experience. But isn’t it possible that even reproducing precisely the whole-brain neural patterns in a sundered brain would, to the contrary, not constitute the bringing about of the whole-brain experience? Couldn’t proximity be not just something to get around in creating a particular whole-brain experience but somehow an absolute condition and principle of the having of a whole-brain experience?”
Cassander got little sympathy for his worries. Typical replies ran something like this: “Would the damn hemispheres know they were connected by wires instead of attached in the usual way? That is, would the fact get encoded in any of the brain structures responsible for speech, thought or any other feature of awareness? How could this fact about how his brain looks to external observers concern our dear friend in his pleasures at all—any more than being a naked brain sitting in a warm nutrient bath does? As long as the neural activity in the hemispheres—together or apart—matches precisely that which would have been the activity in the hemispheres lumped together in the head of a person walking around having fun, then the person himself is having that fun. Why, if we hooked up a mouth to these brain parts, he’d be telling us through it about his fun.” In reply to such answers, which were getting shorter and angrier, Cassander could only mutter about the possible disruption of some experiential field “or some such.”
But after the men had been working on the wires for a while someone else came up with an objection to their project that did stop them. He pointed out that it took practically no time for an impulse from one hemisphere to enter into the other when a brain was together and functioning normally. But the travel of these impulses over wires must impose a tiny increase on the time taken in such crossovers. Since the impulses in the rest of the brain in each hemisphere would be taking their normal time, wouldn’t the overall pattern get garbled, operating as if there were a slowdown in only one region? Certainly it would be impossible to get precisely the normal sort of pattern going—you’d have something strange, disturbed.
When this successful objection was raised, a man with very little training in physics suggested that somehow the wire be replaced by radio signals. This could be done by outfitting the raw face—of the split—of each hemisphere with an “impulse cartridge” that would be capable of sending any pattern of impulses into the hitherto exposed and unconnected neurons of that hemisphere, as well as of receiving from those neurons any pattern of impulses that that hemisphere might be trying to communicate to the other hemisphere. Then each cartridge could be plugged into a special radio transmitter and receiver. When a cartridge received an impulse from a neuron in one hemisphere intended for a neuron of the other, the impulse could then be radioed over and properly administered by the other cartridge. The fellow who suggested this even mused that then each half of the brain could be kept in a separate bath and yet the whole still be engaged in a single whole-brain experience.