I had originally started my last post wanting to talk about what I think about the mind/body problem, but got derailed with what I (maybe narcissistically) thought was an interesting story about how I got where I am. With that out of the way, I'd like to discuss how I think the mind/body problem arises and what can be done about it. This is largely a rephrasing of what David Chalmers had to say about consciousness in The Conscious Mind (1998), but I hope it's helpful anyway.
Chalmers spends a long portion in the beginning of his book discussing Philisophical Zombies (or p-zombies, see Wikipedia and the Stanford Encyclopedia). The idea behind a p-zombie is that unlike regular zombies it behaves externally just like a person: eats just like a person, laughs just like a person, etc. but internally it is devoid of consciousness. If you were to take this idea way too seriously, you might wonder whether other people in your life are actually conscious or just p-zombies, but please don't do that.
So if we don't think they really exist, why talk about p-zombies at all? The reason is that given the current scientific perspective, everyone looks more like a p-zombie than an actually conscious person. Science so far has done wonderfully with reductionist explanations of things we observe. Why is the sky blue? Because the air in the atmosphere diffracts light in a certain way. Why does it diffract light in that particular way? Because of the mixture and arrangement of its atoms. Why do atoms behave that way? Because they are made of electrons protons and neutrons that behave a certain way. I'm not sure I could keep going with this too much longer, but at some point you get to quantum physics, which is ludicrously accurate at predicting the behavior of very small objects, and we don't have anything at a smaller scale than that. So given that very low-level theory, we should be able to put together pieces and get a human. Start with quantum stuff, work your way up to atoms, build up atoms to proteins and other complex chemicals. Those chemicals sit an a lump called a cell. Some cells that we particularly care about (neurons) have excitable membranes that change voltage very suddenly. That voltage change gets transmitted along the neuron until it gets to another cell and either transmits current directly into that cell or releases neurotransmitters. Then the next cell gets excited and the process continues. Getting into the neuroscience side of things now, we know that the spiking of some neurons are modified by inputs to a human (sensory stuff like touch, taste, sight, hearing, etc.) and that other neurons spiking causes our muscles to undertake the actions we humans take as well as controlling a bunch of stuff in the rest of our body. Combine all that with the fact that we can prove that a large network of simplified neurons can compute anything (yes, anything, so long as the network is big enough) and that means that baring working out the (ludicrously complicated but not metaphysically mysterious) details we have a really good theory to explain human behavior entirely.
But hold on, we now have a model that is a bunch of entirely unthinking unconscious particles following basic laws in an certain way to produce actions that mimic thoughts and consciousness. That sounds like... a p-zombie! One solution that you might hear a lot is that mimicking consciousness IS consciousness. I think the phrases "We're just a bag of chemicals", or "love is just a hormone in your brain" are both sentiments that reflect this idea. Another solution is to say that your brain makes you believe you are conscious but you really aren't. This seems like a cop out, since it denies one of your most basic direct experiences. These explanations don't explain why it is different to actually be you instead of being an external observer.
The correct approach when you see this kind of a contradiction between your model of the physical world (which is essentially a p-zombie) and reality (the fact that you do in fact have conscious experiences that aren't just a behavioral or computational trick), is to first recognize that your model is incomplete and then look for ways to get data to guide you in improving your model. Chalmers suggests trying to correlate what people report themselves as being conscious of as a start for getting data, which I think is a good place to start. Then, after figuring out many of those ludicrously complicated but not metaphysically mysterious details I mentioned earlier, we might be able to see what physical reactions or computations correspond to conscious experience and go from there.
I love having this framework in my head to remind myself why all the intricate details of the physics of the brain are guiding the human race towards an understanding of something that has mystified us for so long. It's an awesome project to be part of.
Wednesday, January 18, 2017
Wednesday, January 4, 2017
What I Like About the Brain
Before I got to grad school, I knew I was interested in the brain, but I'm not sure I really knew why. The brain is an amazing piece of hardware that is able to compute pretty much anything using much less power than your average computer with more memory and processing power. It is more creative than any existing computer. It can process visual and audio input better than any computer (baring weird optical and audio illusions). Robots have just developed walking in the last few years while each human can figure it out in about a year along with a host of other motor behaviors. I was surprised to find out over the course of my studies that I don't care a ton about all of this. It certainly isn't what gets me up in the morning.
There is lots of really cool technology associated with the brain that is really interesting. I still don't know the math behind how fMRI works and some day I'd like to read up on it. I know it uses a time-varying magnetic field (which is why you don't want to wear conductive metal anything in there, especially loops of metal), and I know it does some transformation from a frequency domain representation of the blood-oxygen signal into a spatial representation, but I don't know a number of important details to figure out how it does those things, and I have to admit it would be fun to learn. I even worked in an fMRI lab one summer in undergrad, but was surprised that I didn't enjoy the field very much. Why? At the time I couldn't really say. Some of it was that I thought the interpretation of experiments was a little overblown, but I don't think that captured all of my internal issues.
There is also the incredibly sexy technology known as Brain-Machine Interfaces (BMIs), which connect a computer (or a robot arm, or whatever) to the brain or the nervous system by a set of electrodes (wires) measuring the activity of neurons. I originally went to graduate school to study and hopefully improve on BMIs, but after the initial wow factor wore off I once again found myself frustrated with work. While the idea of making cyborgs sounds amazing (who wouldn't want to say they build cyborgs for a living?), the practice was difficult, as all research is, and rather than push through that difficulty I found myself asking why I cared. The other problem was that I found very little reason to choose between any given change in how BMIs already work. Though we know a fair bit about the brain, we don't really know a lot about how to hook up electrodes in a useful way to the brain. We mostly just place the wires and then let the brain figure out what to do with them. It usually does an okay job, but we don't know what the brain is doing so its difficult (or a very long research program) to try to figure out how to make things better.
So between working on fMRI and BMIs I had read books and articles about the brain for non-neuroscientists that had grabbed my attention. I liked some portion of A Universe of Consciousness that discussed the idea of "The World Knot", which was their way of describing the interlinking between personal experience and the rest of the world, though I found it unsatisfactory. I had also liked The Brain that Changes Itself as an introduction to some of the complexity of neuroscience and changes in the scientific perspective since I was younger.
Finally, the biggest personal reason that I thought "of course the brain is interesting" is that it is a big complicated puzzle. Generally speaking, I love puzzles. I play lots of puzzle games in my spare time and fiddle with a Rubik's Cube every now and then, refusing to look up how to do them because I want to figure it out myself. But what is the puzzle of the brain that is interesting? When I was looking for labs in neuroscience, many of them studied one aspect of the brain or another. They would pick an area of the brain that they thought was interesting, or a topic like visual input, motor control, memory, or attention. Each of these sound like fields with lots of hard questions but again I didn't find myself terribly attached to any of them.
In the summer of 2015, after I had already settled in my current lab, I watched TED talk by David Chalmers, which gave me the rare experience of feeling like someone else is explaining my own unconscious thoughts to me. I usually don't love TED talks because they tend to oversimplify things, but I thought Chalmers did a really good job.
The brain is interesting because it is the only thing that we are really sure has experiences. Experiences are so fundamental to our existence that we have to learn that other things don't have them. By the time you're an adult, you think of a rock as something that doesn't move unless something pushes it, and when it does move it doesn't care in the least. If someone said "What is it like to be a rock?" you'd laugh at them because rocks don't have experiences. But you do! Why? I don't know, but that's what's so interesting! With this perspective, suddenly the fields of sensation, motor control, memory, attention, and bits of computer science all seem really interesting in how they relate to this more fundamental question. So these days I study attention with the hope that as we improve our understanding of how the pieces of the brain work together, we will be able to work out how the computations performed by the brain allow it to be conscious and have experiences instead of just being like a wet rock.
I'll end this with some suggested reading: The Conscious Mind by David Chalmers, and Consciousness Explained by Dan Dennett. Both books are dense but interesting. I only read the last few chapters of Consciousness Explained because the rest was only tangentially related to my interests, but I read nearly all of The Conscious Mind. Dennett argues that anything that acts like it has a mind must be conscious (I disagree), but reading both sides of this argument helps keep an open mind and helps me try to avoid mental pitfalls that are easy to fall into when reading philosophy. Chalmers argues that we need to add mental properties to our understanding of the universe to explain consciousness because modern physics does not predict the existence of an internal mental experience (I agree).
PS - Happy 2017!
There is lots of really cool technology associated with the brain that is really interesting. I still don't know the math behind how fMRI works and some day I'd like to read up on it. I know it uses a time-varying magnetic field (which is why you don't want to wear conductive metal anything in there, especially loops of metal), and I know it does some transformation from a frequency domain representation of the blood-oxygen signal into a spatial representation, but I don't know a number of important details to figure out how it does those things, and I have to admit it would be fun to learn. I even worked in an fMRI lab one summer in undergrad, but was surprised that I didn't enjoy the field very much. Why? At the time I couldn't really say. Some of it was that I thought the interpretation of experiments was a little overblown, but I don't think that captured all of my internal issues.
There is also the incredibly sexy technology known as Brain-Machine Interfaces (BMIs), which connect a computer (or a robot arm, or whatever) to the brain or the nervous system by a set of electrodes (wires) measuring the activity of neurons. I originally went to graduate school to study and hopefully improve on BMIs, but after the initial wow factor wore off I once again found myself frustrated with work. While the idea of making cyborgs sounds amazing (who wouldn't want to say they build cyborgs for a living?), the practice was difficult, as all research is, and rather than push through that difficulty I found myself asking why I cared. The other problem was that I found very little reason to choose between any given change in how BMIs already work. Though we know a fair bit about the brain, we don't really know a lot about how to hook up electrodes in a useful way to the brain. We mostly just place the wires and then let the brain figure out what to do with them. It usually does an okay job, but we don't know what the brain is doing so its difficult (or a very long research program) to try to figure out how to make things better.
So between working on fMRI and BMIs I had read books and articles about the brain for non-neuroscientists that had grabbed my attention. I liked some portion of A Universe of Consciousness that discussed the idea of "The World Knot", which was their way of describing the interlinking between personal experience and the rest of the world, though I found it unsatisfactory. I had also liked The Brain that Changes Itself as an introduction to some of the complexity of neuroscience and changes in the scientific perspective since I was younger.
Finally, the biggest personal reason that I thought "of course the brain is interesting" is that it is a big complicated puzzle. Generally speaking, I love puzzles. I play lots of puzzle games in my spare time and fiddle with a Rubik's Cube every now and then, refusing to look up how to do them because I want to figure it out myself. But what is the puzzle of the brain that is interesting? When I was looking for labs in neuroscience, many of them studied one aspect of the brain or another. They would pick an area of the brain that they thought was interesting, or a topic like visual input, motor control, memory, or attention. Each of these sound like fields with lots of hard questions but again I didn't find myself terribly attached to any of them.
In the summer of 2015, after I had already settled in my current lab, I watched TED talk by David Chalmers, which gave me the rare experience of feeling like someone else is explaining my own unconscious thoughts to me. I usually don't love TED talks because they tend to oversimplify things, but I thought Chalmers did a really good job.
The brain is interesting because it is the only thing that we are really sure has experiences. Experiences are so fundamental to our existence that we have to learn that other things don't have them. By the time you're an adult, you think of a rock as something that doesn't move unless something pushes it, and when it does move it doesn't care in the least. If someone said "What is it like to be a rock?" you'd laugh at them because rocks don't have experiences. But you do! Why? I don't know, but that's what's so interesting! With this perspective, suddenly the fields of sensation, motor control, memory, attention, and bits of computer science all seem really interesting in how they relate to this more fundamental question. So these days I study attention with the hope that as we improve our understanding of how the pieces of the brain work together, we will be able to work out how the computations performed by the brain allow it to be conscious and have experiences instead of just being like a wet rock.
I'll end this with some suggested reading: The Conscious Mind by David Chalmers, and Consciousness Explained by Dan Dennett. Both books are dense but interesting. I only read the last few chapters of Consciousness Explained because the rest was only tangentially related to my interests, but I read nearly all of The Conscious Mind. Dennett argues that anything that acts like it has a mind must be conscious (I disagree), but reading both sides of this argument helps keep an open mind and helps me try to avoid mental pitfalls that are easy to fall into when reading philosophy. Chalmers argues that we need to add mental properties to our understanding of the universe to explain consciousness because modern physics does not predict the existence of an internal mental experience (I agree).
PS - Happy 2017!
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