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Managing director, Excel Venture Management; coauthor (with Steve Gullans), Evolving Ourselves: How Unnatural Selection and Nonrandom Mutation Are Changing Life on Earth
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In the pantheon of gruesome medical experiments, few match head transplants. Animal experiments have attempted this procedure in two ways: substituting one head for another or grafting a second head onto the animal. So far, the procedure hasn’t been very successful. But we’re getting far better at vascular surgery—bypassing, stitching, and grafting both big and microscopic vessels. There have been similar advances in rebuilding muscles and damaged vertebrae. Even the reattachment of severed spinal cords in mice and primates is progressing.
Partial brain transplants are likely a long way off. Other than in certain stem-cell procedures, attaching parts of one brain to another is a highly complex undertaking, given the consistency of most brain mass and the trillions of connections. But as extreme operations—reattachment of fingers, limbs, even faces—become commonplace, the question of whether we could, or should, transplant an entire human head looms closer.
Partly reattaching a human head is already a reality. In 2002, a drunk driver hit Arizona teenager Marcos Parra so hard that Parra’s head was almost entirely detached; only the spinal cord and a few blood vessels kept it from coming off. Fortunately, Curtis Dickman, a surgeon at Phoenix’s Barrow Neurological Institute, had been preparing for just this type of emergency. Screws reattached vertebrae to the base of the skull, part of the pelvic bone was redeployed to bring neck and head back together, and within six months Parra was playing basketball.
Successful animal whole-head transplants may not be that far off. And if such procedures are successful and the animal regains consciousness, we can begin to answer pretty fundamental questions, including, Do the donor’s memories and consciousness also transplant?
Similar questions about the emotions, attachments, and loves of the donor were asked during the first heart transplants, though the heart is but a muscle. How about the brain? If mice with new heads recognized mazes previously navigated by the donor mouse, or maintained the donor’s conditioned reactions to certain foods, smells, or stimuli, we’d have to consider the possibility that memory and consciousness do transplant. But if experiment after experiment demonstrates no previous knowledge or emotions, then we’d have to consider that the brain, too, might just be an electrochemical muscle.
Discovering whether or not you can transplant knowledge and emotions from one body to another goes a long way toward answering the question, Could we ever upload and store part of our brains into not just another body but into a chip, into a machine? If this could be done, it would make the path to large-scale AI far easier. We would simply have to copy, merge, and augment existing data—data we would know are transferable, stackable, manipulatable. The remaining question would be, What is the most efficient interface between the biology and the machine?
But if it turns out that all data are erased upon transplant and knowledge is unique to the individual organism—in other words, that consciousness/knowledge/intelligence is something innate and individual—then simply copying the dazzlingly complex connectome of brains into machines would likely not lead to an operative intelligence.
If brain data is not transferable or replicable, then to develop AI would require building a parallel machine-thought system, something quite distinct from animal and human intelligence. Building consciousness from scratch implies following a new and different evolutionary path from that of human intelligence. This new system would doubtless operate under different rules and constraints—in which case, although it would likely be far better at certain tasks, it would be unable to emulate some forms of our intelligence. Were AI to emerge from this kind of evolutionary system, it would represent a new, distinct consciousness, one on a parallel evolutionary track. In this scenario, how machines might think, feel, govern, could have little to do with the billions of years of animal/human intelligence and learning. Nor would such machines be constrained to organize their society and its rules as we do.
