Showing posts with label mind-body problem. Show all posts
Showing posts with label mind-body problem. Show all posts

Friday, 15 March 2019

Mind and Body

Rene Descartes 1596-1650
Descartes took it for granted that "mind" or "soul" existed in different universes. He wondered about how these universes communicated. Specifically, he wondered how "spirit" can move "matter".

There are many who still take the idea of the spirit world seriously. They imagine the "soul" can be separated from the body and migrates on to some other universe (heaven) at death or somehow migrate to another body. Let's put this belief system to one side. From here on, I will speak to those who don't take this idea seriously.

These days, those of us who are scientifically inclined imagine the "mind" to be a phenomenon that somehow happens in the Universe that is governed by physical law (and perhaps other laws so far undiscovered). Exactly how this happens is a live debate and a key area of investigation in the new university departments of "Cognitive Studies". These same departments work on another hot subject: machine learning and "artificial intelligence". Naturally, these two issues tend to overlap, producing "computational" theories of "mind". It's quite respectable these days to consider "mind" to be some kind of computation that could, in principle, happen on a computer.

I'm not too impressed by "computational" theories. As far as I can see, they tend to side-step the core question and propose some kind of hypothetical process that bears no obvious relationship to "mind" as we experience it nor, for that matter, much to do with actual brains.

The debate over the mechanism of consciousness draws a lot of attention away from the core issue, whatever the mechanism may be. These debates also tend to assume that consciousness is something that happens in the brain: an assumption that has become so "obvious" that it is rarely questioned. This is partly due to the "computational" theories, which picture the brain as a kind of computer. What else could it be? It is an uphill fight to wrench people away from this metaphor, but the clues are easy to find if you examine what human consciousness is actually like. It also helps to have a few decades of experience with computers. My experience with simulated people like Alexis and Siri reinforces my impression that "there is nobody home".

The more you learn about the brain (and we are just starting to learn about this), the more we learn about how the brain plays a central role in creating "mind", but the picture changes when we ask What the brain is for? What is it doing? No organ in the human body exists for its own sake. The brain is one of the largest and most energetically expensive organs in the body. What is it doing?

Suppose Rip Van Winkle came to life in 2019 after a 40-year sleep. We hand him an iPhone and ask him about it. After a few hours of careful investigation, he might guess that it's a tiny computer operated with a touch screen, which is kinda true. What he might miss is that the essence of the thing is its ability to communicate with the outside world. It's a phone (which Rip may understand) but it's "aware" of its location and its orientation. It's constantly chatting with the owner and the outside world, warning of upcoming radar, suggesting places to eat, keeping the user up to date on the news and assisting the owner to navigate the real world. The essential role of an iPhone is to "know" the status of the owner and to connect relevantly to the outside world. It's like a little "mind". More precisely, it's a tool that extends the power of the mind.  It gives us a clue about what a mind is.

My claim is that an iPhone may be a computer, but this fact hardly describes its role in the world or the role it plays in the owner's life. Similarly, whatever the brain may be doing, and whatever neuroscience may tell you about how it "works", you will not know what it is for, how it works and what benefit it bestows on the owner. In fact, the role of the brain resembles the role of the iPhone. It "knows" about its internal state, the location of the owner. It handles inbound and outbound messages. Unbidden, it alerts the owner to relevant local information and opportunities and so forth. Subjectively, all these things add up to what we call "mind"*. The brain's role in creating mind is undisputed but, like the iPhone, that role makes no sense if we ignore the role of the outside world, the needs of the owner and the interests of the owner in participating in society by personal messages and general information. You may say that the brain creates consciousness but the consciousness is not "in" the brain. The brain strikes a match which lights a fire that joins in the conflagration that is the shared experience of all human society. Participation in this conflagration is what it feels like to be conscious.

The way that all that happens in the brain is still a huge mystery. It may not even make sense to ask why it feels the way it does (the "hard problem"). It is, however, quite clear to me that we will never understand consciousness by ignoring everything that goes on outside our brain. In my view, we can learn a great deal about "mind" by exploring the parts of "mind" that are wide open for investigation, such as language, memory, perception and decision making. I see the mind in two ways: mind in the world and world in the mind. By studying the world itself, we discover the mind that creates and "models" the world. We can also study the "mind" (especially the brain) as an object in the world.

It may turn out that the brain is, after all, doing a kind of "computation". It seems to be doing other things that computers do, such as retaining memory, sensing the body and the world, controlling a "puppet" body and so forth. All this is appropriate to any kind of brain - the brain of a worm, for example. But we don't want to stop there. We are interested in the mind of human beings. Human minds do things like write symphonies and build space ships. That's the part of "mind" that interests us. That's the phenomenon of mind that is interested in itself.

My dog is very smart. She has a brain that follows the same mammalian architecture of my own. Her brain does all the kinds of "brain things" that I mentioned above. The "computational" power of her brain is probably not orders of magnitude different from my own. But she doesn't know she's a dog, nor is she curious about it. It would certainly be interesting to know all about how her brain works and what kind of a "mind" she has. This would certainly tell us a lot about how my own brain works. But it would hardly tell me much about my mind, which seems to participate in all human experience.

It's natural to think of "mind" as something that arises in the brain due to the complex physical connections between neurons. That's kinda like a computer, isn't it? Perhaps we need a different metaphor. Maybe something based on 21st-century computers, not the computers of 1960. The Internet is created by connections between multiple "hosts" - usually computers. These connections need not be physical (think cell phones and WIFI). The way they are connected is irrelevant to the way they work and what they are for. Most of these hosts are in the business of communicating with other hosts, usually for the purpose of sharing information. Similarly, our "minds" are connected to other minds through speech (sound waves and marks on paper) and many other indirect ways. Breaking these non-physical connections produces a serious degradation in the function of "mind", like turning your computer into an old fashioned "stand-alone" machine with no Google, no Email etc. A brain that is never "connected" to the outside world or other minds is a baby without much of a mind at all. You may choose to call it a "mind", but it is hardly the kind of "mind" we wish to know about. Not the kind of mind you and I have.

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* Of course, the "mind" is more than what is hinted here. "Consciousness" is a faculty of mind but the mind is far more than that. In fact, it seems that most of what "mind" does operates on an automatic and unconscious level. When considered in detail, much of this operation slips out of the "computational" model, but that's a topic for another day.

Saturday, 17 November 2018

Roots

I have lately become impressed with the what's going on in the brain. Learning more about the small details, I wind up asking myself about the "big picture" that these details reveal. I'm a visual kind of guy, so I'm thinking about a picture something like this:

Neural network in the brain
That picture is showing main connections only - myelinated "high speed" connections. The actual picture would be a packed tangle of axons and dendrites - for example, the massive wad of connections that make up the "white matter" in the brain, connecting (on average) each neuron in the neocortex with 1,000 other neurons.

White Matter in the Brain is a Wad of Connections

Where else do we see something like that?

Roots in the Forest Floor
There is a tangle of roots under our feet in the forest floor. We usually see the big ones that manage to break the surface and threaten to trip us up, but the network is much more extensive, especially in a thriving "old growth" forest. We have recently found that trees are not just sucking up water and nutrients. They are communicating with each other through their root system.

I'm a sucker for analogy. It's natural for me to ask: what is the brain "sucking up" through its "root" system. Obviously, the nervous system is in the business of conveying information from the world (and inside the organism) to other parts of the organism - especially the central nervous system. Information is also being conveyed in the opposite direction - not only to allow us to wiggle our fingers but also to modify how our eyes "see" the world (roughly helping the eyes see things that "matter").

We, as conscious beings, owe our consciousness to our roots in the real world. Our root system is designed on a very fine level to suck every bit of precious information from that world. To take the example of the ganglia* in the eye, we have 20 different ganglia types, extracting 20 different types of information from the raw information provided by the retina. It's easy to think of a few types of information that might be extracted, such as a 2-dimensional map of 3 different colors plus black and white (that's the 4 different types of photoreceptors--rods and cones--in the eye). We imagine that like the image going from our camera retina to the camera memory. What else? At this point, we can only guess. Maybe something like this:

  • Day and night - time to sleep, time to wake
  • Faces
  • Weather
  • Sun location - where am I? What time is it?
  • Movement - comparison with one image with another a fraction of a second later
  • Repeating shapes 
  • Shapes of known objects
  • Basic "camera" adjustments such as the need to increase or decrease exposure, image sharpness, saturation ...
  • Compensation for the fact that the eyes are always moving 
We are all familiar with the experience that something we are looking for, perhaps our car keys, mysteriously seem to "pop out" from the jumble of other things in our field of view. Just two hops from raw data from the photoreceptors - a few centimeters -- our brains extend neurons that are hungrily extracting "meaning". "Upstream" from the visual system, we find brain systems looking for enemies, mating opportunities and chances to maintain status in the group.

Like a tree, we are sucking up what we need to survive. We have left it to the plants and the animals that eat plants to take care of our nutritional needs. We live or die on our ability to extract information from the world. Being "rooted" in the world is perhaps the best metaphor to help us think of our relationship to the world - the "mind-body problem".

Our "roots" analogy can be applied at another level: DNA and evolution.

We may regard the entire history of evolution as the story of life groping in "reality" to find a niche, a body plan and a pattern of reacting the environment that "works". 

Similarly, we can use the same concept with human languages.


We may think of languages as groping through the world of human experience (E) to find an effective way to share the matrix of experience within a culture. Shared experience is a necessary (but not sufficient) condition for what we might call a scientific apprehension of "reality". In any case, this capability seems to be important enough for nature to devote significant parts of our central nervous system to communicate using language.

Of course, the idea applies to the worlds of imagination such as religion, where an entire culture gropes in vain for some kind of sensible, self-consistent way of speaking about a realm that is entirely fictitious.
The Chaotic Imaginary World of Christianity




* You can learn about ganglia in the visual system from Episode 39 of Rob Reid's "After On" Podcast "Restoring Sight to the Blind"