Brain in a Vat — Making Philosophy Manifest I have […]

Brain in a Vat — Making Philosophy Manifest
I have been talking with a fascinating scientist who’s working on genetically-modified neurons to innervate the brain from a silicon substrate. The goal — connect prosthetics to the cranial nerves and eventually, replace all sensory input to the brain with a computer interface. Well… how complicated would this be? While the human brain has 86 billion neurons, he estimates that there are only 4 million cranial nerves to connect, and 3 million of them come from the retina (the color-coded photoreceptors).

Who might volunteer to have their head and spinal cord cut out of their body and their skull removed, to be reborn as a cyborg, fed by an ECMO machine? Many terminally ill cancer patients have not suffered a neurodegenerative disease. Their body will die while the mind is still ripe.

I do not believe we will be able to upload our consciousness to a silicon substate, as Ray Kurzweil has long predicted, at least not any time earlier than we will grow an AI that exceeds human intelligence. The brain in a vat is very different. A prosthetic hijacking of the interface to the sensory cortex is a much simpler task. The inscrutable complexity of the cortex remains just that. We just need to couple to the extant external interface to the body.

He makes it sound… imminent. While the sensory cortex is notable for its neuroplasticity, (the ability to remodel sensory input), can it be this dramatic — from body to borg?

I thought of the adage from Hunter S. Thompson that arose while watching a boxing match on an ether binger: “Kill the body and the head will die.”

Thanks to Genevieve being an MIT alumnus, I can get behind the paywall of the MIT Technology Review October issue on the Mind. Professor Lisa Feldman of Northeastern postulates a problem: “Your brain did not evolve to think, feel, and see. It evolved to regulate your body. Your thoughts, feelings, senses, and other mental capacities are consequences of that regulation. Since allostasis [regulation of body systems] is fundamental to everything you do and sense, consider what would happen if you didn’t have a body. A brain born in a vat would have no bodily systems to regulate. It would have no bodily sensations to make sense of. It could not construct value or affect. A disembodied brain would therefore not have a mind. I’m not saying that a mind requires an actual flesh-and-blood body, but I am suggesting that it requires something like a body, full of systems to coordinate efficiently in an ever-changing world. Your body is part of your mind—not in some gauzy, metaphorical way, but in a very real brain-wiring way.

Your thoughts and dreams, your emotions, even your experience right now as you read these words, are consequences of a central mission to keep you alive, regulating your body by constructing ad hoc categories. Most likely, you don’t experience your mind in this way, but under the hood (inside the skull), that’s what is happening.”

She elaborates, as you might assume: “When your brain remembers, it re-creates bits and pieces of the past and seamlessly combines them. We call this process ‘remembering,’ but it’s really assembling. In fact, your brain may construct the same memory (or, more accurately, what you experience as the same memory) in different ways each time. I’m not speaking here of the conscious experience of remembering something, like recalling your best friend’s face or yesterday’s dinner. I’m speaking of the automatic, unconscious process of looking at an object or a word and instantly knowing what it is. Every act of recognition is a construction. You don’t see with your eyes; you see with your brain. Likewise for all your other senses. Just as your memory is a construction, so are your senses. Everything you see, hear, smell, taste, and feel is the result of some combination of stuff outside and inside your head. Affect is just a quick summary of your brain’s beliefs about the metabolic state of your body, like a barometer reading of sorts.

Brains evolved to control bodies. Over evolutionary time, many animals evolved larger bodies with complex internal systems that needed coordination and control. A brain is sort of like a command center to integrate and coordinate those systems. It shuttles necessary resources like water, salt, glucose, and oxygen where and when they are needed. This regulation is called allostasis; it involves anticipating the body’s needs and attempting to meet them before they arise. If your brain does its job well, then through allostasis, the systems of your body get what they need most of the time.

To accomplish this critical metabolic balancing act, your brain maintains a model of your body in the world. The model includes conscious stuff, like what you see, think, and feel; actions you perform without thought, like walking; and unconscious stuff outside your awareness. For example, your brain models your body temperature. This model governs your awareness of being warm or cold, automatic acts like wandering into the shade, and unconscious processes like changing your blood flow and opening your pores. In every moment, your brain guesses (on the basis of past experience and sense data) what might happen next inside and outside your body, moves resources around, launches your actions, creates your sensations, and updates its model. This model is your mind, and allostasis is at its core.” — From: https://www.technologyreview.com/2021/08/25/1031432/what-is-mind-brain-body-connection/

Anil Seth from the University of Sussex phrases it more strongly: “The brain is always constructing models of the world to explain and predict incoming information; it updates these models when prediction and the experience we get from our sensory inputs diverge.

The entirety of perceptual experience is a neuronal fantasy that remains yoked to the world through a continuous making and remaking of perceptual best guesses, of controlled hallucinations. You could even say that we’re all hallucinating all the time. It’s just that when we agree about our hallucinations, that’s what we call reality.”
— From: https://www.technologyreview.com/2021/08/25/1032121/brains-controlled-hallucination/