Don Page - Physics of Consciousness

We're here at another FQXI conference and in dealing with some of the fundamental questions of quantum physics and cosmology, people are also talking about consciousness, the physics of consciousness. To me, trained in neuroscience, that is kind of astonishing that people who deal with the most fundamental parts of physics, many orders of magnitude below what's happening in the brain, are making creative contributions to what the nature of consciousness is. Now, neuroscience hasn't been able to really explain consciousness, so maybe we need to deal with the underlying physics? Well, because quantum theory is the fundamental description we have in physics, I would like to express the relationship between consciousness and physics in terms of this fundamental description of physics. I'm not denying that it might not be a very good approximation to use the approximation of classical physics to describe consciousness, but I would like to understand the relation between consciousness and the fundamental level of physics. So therefore, I've formulated something that I sometimes call sensible quantum mechanics, because it has to do with sensations, really sentient experiences or conscious perceptions, all at once, aware of at once. And then once I did write something for lay people, I called it mindless sensationalism, because in this, what was fundamental was the sentient experiences and not sequences of them that might be called minds. So I have a framework. It's not a theory, and I'll explain why it's not a theory in the terms. And that says that there's something called the quantum state of the universe. This is what we would get from quantum physics. But then it would say for each sentient experience, each possible total experience of first-person awareness, there is a corresponding positive quantum operator. And a quantum operator is something that the quantum state assigns a number to. So if it's a positive quantum operator, it would assign a positive number to this thing. And the idea is that this positive number would represent what we call the measure or would be to what extent does this sentient experience exist. So if you had the operator for, say, getting 1,000 coins, fair coins, all heads, then the measure for that would be very tiny, because it's extremely improbable to get all 1,000 coins thrown as heads. On the other hand, if you ask for, say, 500 heads, then the probability is 500 heads, 500 tails, the probability is much higher. So I would think that the measure of the corresponding sentient experience of experiencing that you got that result would also be much higher. So it's a framework for saying that the measures for sentient experiences are given by the expectation values of corresponding positive operators in the quantum state of the universe. The reason it's not a theory is that I do not know what these operators are. So to flesh it out, you would have to know what the operators are. Well, you'd also have to know what the quantum state of the universe is. But if you knew the quantum state and you knew the operators, and of course, if this framework were right, then at least it would tell you how much of each sentient experience occurs. Now, how does this help us to understand the phenomenal internal subjective nature of consciousness more than a neuroscientist sitting here who would say that it's the corticothalamic system in the brain firing those X number of neurons at a certain pattern, which is huge numbers of orders of magnitude higher than what's working in the quantum system in all of those neurons? How does it help us? I think, of course, if you could then translate these conditions in the brain into quantum terms, then what the neuroscientists find, that could be information about what these operators are. See, I'm leaving what the operators are as I'm just putting a framework. And so they would be doing the nitty gritty work, which is much harder than my tiny contribution as to just what the framework is. I understand that. But at the end of the day, you have to, if the project is understood, to explain the internal phenomenal experience, not explaining how I'm moving my arm or seeing red, but how I'm feeling it inside. And so I just don't understand how any physical system as we know it today, be it at the quantum level or be it at the neuronal level, can literally be this phenomenal experience. Yeah, that's a mystery I think that David Chalmers has called the hard problem. And I'm not sure that this would, at some level you might say it doesn't really explain it, but if it does describe, if it says exactly what does happen in a situation, it's at least a partial explanation. I mean, of course, one could say a similar thing. You could say, how could a particle ever have an electric field associated with it? And I don't know that physics really explains that, but it does say we have the equations that imply that for each charged particle, there's an associated electric field coming out of it. An electron has electric field coming out of it. And so we have a description of how strong this electric field is. It depends on the charge of the particles. And I guess it's a little bit of an open question is, does that really explain why the field is there? It gives a good description. And that's at least the first stage that we would want. And I think David Chalmers was telling me today that, you know, he would be happy with that if we had a good description that we were able to predict the sentient experiences from the quantum state, then that might be all that you could expect science to answer. Now when you're doing that, you're using the quantum state in all of these neurons, however it's working, to give us a framework to think better about it. So my question is, that same quantum analysis is occurring in this chair, my pants, the floor, everything in the world. What's so special about the quantum states and operators occurring in the brain? Is it something special in the brain that's helping it, or it's the same quantum activity that's going on everywhere? Well, these operators, of course, in some sense, they're looking for particular situations. I mean, in some crude sense, this measure that you get out from the operator, in some sense, says how nearly is the brain state to that described by the operator. So if the operator is looking for a brain in some particular configuration, or well, it's looking for some matter that's in a particular configuration that would be, say, what a normal conscious human brain would have. OK, so we're saying that if then it finds that matter in the brain, but it doesn't find it in your knee. It looks, it looks, it looks all over your knee and your toe and everywhere else to see is there some structure that would produce the consciousness. And if what produces the consciousness is like some particular structure in a normal human brain, then it's, of course, extremely unlikely to find that same structure in the knee, which just has a different structure. When you say it's looking, what's the it? Well, the it would be, I'm sort of anthropomorphizing this operator. I'm trying to describe the expectation by this operator. Is it in some, it's as if this operator is trying to look for situations that correspond to particular configurations. And if it's, if consciousness is produced by brain, certain brain configurations, it's looking for those brain configurations. And I'm sort of, I'm saying that in some sense, it doesn't matter where these configurations are. But of course, in reality, we find them, we find them inside human brains and we, and we're extremely, well, for all practical purposes, we don't find them, you know, in other parts of the human body or, or, you know, or in inanimate objects and so on. Now, it's an open question whether different configurations corresponding to perhaps sufficiently intelligent computers might also be sufficient to produce consciousness. That would be a different, it would maybe be a different operator that was looking for some particular computer thing. And I'm agnostic as to, you know, to what extent any present computers, whether any of these operators might find consciousness within, you know, any present, I'm rather skeptical that in present computers, it would find very much consciousness.