A while back, I highlighted a TEDX talk by Anil Seth where he discussed that cognition is largely a prediction machine. Apparently Seth more recently gave another talk at the full TED conference, which is receiving rave reviews. Unfortunately, that talk doesn’t appear to be online yet.
But one article reviewing the talk focuses on something Seth purportedly said in it, that uploading minds is impossible because the mind and body are tightly bound together.
Seth’s work has shown compelling evidence that consciousness doesn’t just consist of information about the world traveling via our senses as signals into our brains. Instead, he’s found that consciousness is a two-way street, in which the brain constantly uses those incoming signals to make guesses about what is actually out there. The end result of that interplay between reality and the brain, he says, is the conscious experience of perception.
“What we perceive is [the brain’s] best guess of what’s out there in the world,” he said, explaining that these guesses are constantly in flux.
…“We don’t passively see the world,” he said, “we actively generate it.” And because our bodies are complicit in the generation of our conscious experience, it’s impossible to upload consciousness to some external place without somehow taking the body with it.
Everything Seth describes conforms with most of the neuroscience I’ve read. To be clear, the brain is indeed tightly bound with the body. Most of it is tightly focused on interpreting signals sent to it from throughout the peripheral nervous system, and much of the rest is focused on generating movement or hormonal changes. The portions involved in what we like to think of as brainy stuff: mathematics, art, culture, etc, is a relatively tiny portion.
And the brain appears to have very strong expectations about the body it’s supposed to be in. That expected body image may actually be genetic. In his book, The Tell-tale Brain, neuroscientist V.S. Ramachandran describes a neurological condition called apotemnophilia where patients want part of their body removed because they don’t feel like it should be there (to the extent that 50% of people with this condition go on to actually have the body part amputated). It’s as though their expected body image has become damaged in some way, missing a part of their actual physical body.
If apotemnophilia is a standard brain mechanism gone awry, then a normal human mind is going to have very strong expectations of what kind of body it will be in. This makes science fiction scenarios of removing someone’s brain and installing it as the control center of a machine an unlikely prospect, at least without dealing with far more complex issues than successfully wiring the brain into a machine.
But ultimately, I don’t think this makes copying a mind impossible, although it does put constraints on the type of environment the copied mind might function well in. If the mind has strong expectations about its body, then a copied mind will need to have a body. A mind uploaded into a virtual environment would need a virtual body, and a mind installed in a robotic body would need that body to be similar to its original body. (At least initially. For this discussion, I’m ignoring the possibility of later altering the mind to be compatible with alternative bodies.)
But doesn’t the tight integration require that we take the entire body, as Seth implies? We could insist that copying a mind requires that the person’s entire nervous system be copied. This would raise the difficulty, since instead of just copying the brain, the entire body would have to be copied.
Alternatively, a new nervous system could be provided, one that sends signals similar to the original one. This requires that we have an extremely good understanding of the pathways and signalling going to and from the brain. But if we’ve developed enough knowledge and technology to plausibly copy the contents of a human brain, understanding those pathways seems achievable.
The question is, what exactly is needed to copy a person’s mind? If we omit the peripheral nervous system, are we perhaps leaving out something crucial? What about the spinal cord? When pondering this question, it’s worth noting that patients who’ve suffered a complete severing of their upper spinal cord remain, mentally, the same person they were before.
Such patients still have a functioning vagus nerve, the connection between the brain and internal organs. But in the past, patients with severe peptic ulcer conditions would sometimes have vagotomies, where the vagus nerve to the stomach was partially or completely severed, without compromising their mental abilities.
Certainly the severing of these various nerve connections might have an effect on a person’s cognition, but none of them seem to make that cognition impossible. Every body part except the brain has been lost by somebody who continued to mentally be the same person. The human mind appears to be far more resilient than some scientists give it credit for.
Indeed, the fact that a person can remain partially functional despite damage to various regions to the brain demonstrates that this doesn’t stop at the spinal cord. Which raises an interesting question, does the entire brain have to be copied to copy a human mind?
The short answer appears to be no. The lower brain stem seems to be well below the level of consciousness and is very tightly involved in running autonomous functions of the body. In a new body, it could probably be replaced.
The same could be said for the cerebellum, the compact region at the lower back of the brain involved in fine motor coordination. Replace the body, and there’s no reason this particular region would need to be preserved. In fact, patients who have suffered catastrophic damage to their cerebellum are clumsy, but appear to remain mentally complete.
That leaves the mid-brain region and everything above, including the overall cerebrum. Strangely enough, of the 86 billion neurons in the brain, these regions appear to have less than 25 billion of them. (Most of the brain’s neurons are actually in the cerebellum. Apparently fine motor coordination takes a lot of processing capacity.) It’s even conceivable that lower levels of the cerebral sensory processing regions could be replaced to match the new sensory hardware in a new body without destroying human cognition.
Obviously all of this is very speculative, but then people are often content to entertain concepts like faster-than-light spaceships, which would require a new physics, as merely a matter of can-do spirit. All indications are that mind copying wouldn’t require a new physics, only an ability to continue studying the physics of the brain.
Unlike the singularity enthusiasts, I doubt this capability will happen in the next twenty years. It seems more likely to be something much farther in the future, although it’s unlikely to be developed by those who’ve already concluded it’s impossible.
But is there an aspect of this I’m missing? Something (aside from incredulity) that does in fact make mind copying impossible?