John Searle on Consciousness and the Brain at TEDxCERN (Transcript)

I think now you might actually get tenure by working on consciousness, and if so, that’s a real step forward.

Now why then, is this curious reluctance and curious hostility to consciousness? Well, I think it’s a combination of two features of our intellectual culture that like to think they are opposing each other but in fact they share a common set of assumptions. Consciousness is not a part of the physical world, it’s part of the spiritual world, it belongs to the soul, and the soul is not a part of the physical world. That’s the tradition of God, the soul, and immortality.

There is another tradition that I think is opposed to this but accepts the worst assumption. That tradition thinks we are heavy-duty scientific materialists, consciousness is not a part of the physical world, either it doesn’t exist at all or it is something else, a computer program or some damn fool thing. But in any case, it’s not part of science. And I used to get in an argument that really gave me a stomachache. Here is how it went: “Science is objective, consciousness is subjective, therefore, there cannot be a science of consciousness.” I love that argument because it has got a wonderful fallacy of ambiguity over the concept of objectivity. And I have already used up too much time just to clearing my breath, sort of speak, but I want to get to that.

OK, so these twin traditions are paralyzing us, and it’s very hard to get out of these twin traditions, and I have only one real message in this lecture, and that is consciousness is a biological phenomenon, like photosynthesis, digestion, mitosis, you know all that biological phenomena. And once you accept that, most, though not all, of the hard problems about consciousness simply evaporate. And I am going to go through some of them.

OK, now I promised you to tell you some of the outrageous things said about consciousness, and just because of shortage of time, I am only going to mention four of the worst.

One: “Consciousness does not exist. It is an illusion, like sunsets.” Science has shown sunsets and rainbows are illusions, so consciousness is an illusion.

Two: “Maybe it exists, but it is really something else, it’s a computer program running in the brain.”

Three: “No, the only thing that exists is really behavior!” It’s embarrassing how influential behaviorism was, but I will get back to that.

And four: “Maybe consciousness exists, but it can’t make any difference to the world. How could spirituality move anything?” And whenever somebody tells me that, I think: “You want to see if spirituality moves something? Watch!” I decide consciously to raise my arm and the damn thing goes up.

Furthermore, notice this — we do not say: “Well, it’s a bit like the weather in Geneva, some days it goes up and some days it doesn’t go up.” No! It goes up when I right damn well want it to. OK, I am going to tell you how that is possible.

Now, I haven’t yet given you a definition, you can’t do this if you don’t give a definition. People always say: “Consciousness is very hard to define.” I think it is rather easy to define if you are not trying to give a scientific definition. We are not ready for a scientific definition, but here is the common sense definition: consciousness consists of all those states of feelings, or sensations, or awareness; it begins in the morning when you wake up from a dreamless sleep, and it goes on all day, until you fall asleep, or die, or otherwise become unconscious. Dreams are a form of consciousness on this definition. Now that’s the common sense definition, that’s our target; if you are not talking about that, you are not talking about consciousness.

But they think:”Well, that’s it. That’s an awful problem. How can such a thing exist as part of the real world?” And this, if you have ever had a philosophy course, this is known as the famous “mind-body problem.” I think that has a simple solution to it and I am going to give it to you. And here it is: all of our conscious states, without exception, are caused by lower-level neurobiological processes in the brain. And they are realized in the brain as higher-level or system features. It is about as mysterious as the liquidity of water, right? The liquidity is not an extra juice squirted out by the H2O molecules, it’s a condition that the system is in. And just as the jar full of water can go from liquid to solid, depending on the behavior of the molecules, so your brain can go from a state of being conscious to a state of being unconscious, depending on the behavior of the molecules. The famous “mind-body problem” is that simple.

All right. But now, we get into some harder questions. Let’s specify the exact features of consciousness so that we can then answer those four objections that I made to it.

Well, the first feature is it is real and irreducible. You can’t get rid of it. You see, the distinction between reality and illusion is the distinction between how things consciously seem to us and how they really are. If consciousness seems like… I like the French “arch”, it seems like there’s an arch in the sky, or it seems like the sun is setting over the mountains, it consciously seems to us but that’s not really happening. But for that distinction, between how things consciously seem and how they really are, you can’t make that distinction for the very existence of consciousness. Because where the very existence of consciousness is concerned, if it consciously seems to you, that you are conscious, you are conscious. I mean if a bunch of experts come to me and say: “We are heavy-duty neurobiologists and we’ve done a study on you Searle,” and we are convinced you are not conscious. You’re a very cleverly constructed robot.”

I don’t think: “Well, maybe these guys are right.” I don’t think that for a moment. Because, I mean, Descartes may have made a lot of mistakes but he was right about this: you cannot doubt the existence of your own consciousness. That’s the first feature of consciousness. It is real and irreducible. You cannot get rid of it by showing that it’s an illusion, in a way that you can with other standard illusions.

The second feature is this one that has been such a source of trouble to us. And that is all of our conscious states have this qualitative character to them; there is something that it feels like to drink beer, which is not what feels like to do your income tax, or listen to music.

And this qualitative field automatically generates a third feature, namely, conscious states are by definition subjective, in the sense that they only exist as experienced by some human or animal subjects, some self that experiences them. Maybe we will be able to build a conscious machine. Since we don’t know how our brains do it, we are not in the position so far to build a conscious machine.

Okay, another feature of consciousness is that it comes in unified conscious fields. So I don’t just have the sight of people in front of me, and the sound of my voice, and the weight of my shoes against the floor, but they occur to me as part of one single great conscious field that stretches forward and backward. That is the key to understanding the enormous power of consciousness. And we have not been able to do that in a robot. The disappointment of robotics derives from the fact that we don’t know how to make a conscious robot, so we don’t have a machine that can do this kind of thing.

The next feature of consciousness after this marvelous, unified conscious field is that it functions causally in our behavior. I gave you a scientific demonstration by raising my hand, but how is that possible? How can it be that this thought in my brain can move material objects? Well, I will tell you the answer. I mean we don’t know the detailed answer, but we know the basic part of the answer — and that is, there are sequences of neuron firings and they terminate where the acetylcholine is secreted at the axon end-plates of the motor neurons, sorry to use philosophical terminology here. But when it is secreted at the axon end-plates of the motor neurons, a whole lot of wonderful things happen in the ion channels and the damned arm goes up.

Now think of what I have told you. One and the same event, my conscious decision to raise my arm has a level of description where it has all of these touchy-feely, spiritual qualities, it’s a thought in my brain but at the same time, it’s busy secreting acetylcholine and doing all sorts of other things as it makes its way from the motor cortex down through the nerves fibers and the arm.

Now, what that tells us is that our traditional vocabularies for discussing these issues, are totally obsolete. One and the same event, has a level of description where it’s neurobiological, and another level of description where it’s mental, and that’s a single event and that’s how nature works, that’s how it’s possible for consciousness to function causally.

Now, with that in mind, with going through these various features of consciousness, let’s go back and answer some of those early objections.

Well, the first one I said, was consciousness doesn’t exist, it’s an illusion. Well, I’ve already answered that, I don’t think we need to worry about that.

But the second one, had an incredible influence and may still be around, and that is if consciousness exists, it’s really something else; it’s really a digital computer program running in your brain, and that’s what we need to do to create consciousness, is get the right program. Forget about the hardware, any hardware will do, provided it’s rich enough and stable enough to carry the program.

Now, we know that that’s wrong. I mean, anybody who’s thought about computers at all can see that that’s wrong. Because computation is defined as symbol manipulation, usually thought of as 0s and 1s, but any symbols will do. You get an algorithm that you can program in a binary code and that’s the defining trait of the computer program. But we know that’s purely syntactical, that’s symbolic, we know that actual human consciousness has something more than that, it’s got a content, in addition to the syntax, it’s got a semantics.

Now, I made that argument, — oh, my god, I don’t want to think about it — more than 30 years ago, but there is a deeper argument implicit in what I’ve told you. And I want to tell you that argument briefly, and that is: consciousness creates an observer independent reality. It creates a reality of money, property, government, marriage, CERN, conferences, cocktail parties, and summer vacations. And all of those are creations of consciousness. Their existence is observer-relative. It’s only relative to conscious agents; that a piece of paper is a money, or a bunch of buildings is a university.

Now, ask yourselves about computation. Is that absolute? Like force, and mass, and gravitational attraction? Or is it observer-relative? Well, some computations are intrinsic. I add two plus two to get four, that’s going on no matter what anybody thinks. But when I hold out my pocket calculator and do the calculation, the only intrinsic phenomenon is the electronic circuit and its behavior. That’s the only absolute phenomenon. All the rest is interpreted by us.

Computation only exists relative to consciousness. Either a conscious agent is carrying out the computation or it has got a piece of machinery that admits of a computational interpretation. Now that doesn’t mean computation is arbitrary, I spent a lot of money on this hardware, but we have this persistent confusion between objectivity and subjectivity as features of reality, and objectivity and subjectivity as features of claims.

And the bottom line of this part of my talk, is this: you can have a completely objective science, a science where you make objectively true claims about a domain whose existence is subjective, whose existence is in the human brain, consisting of subjective states or sensations, or feeling, or awareness. So the objection, that you can’t have an objective science of consciousness because it’s subjective, and science is objective, that’s a pun, that’s a bad pun on objectivity and subjectivity. You can make objective claims about a domain that is subjective in its mode of existence, and indeed, that’s what neurologists do. You have patients that actually suffered pains and you are trying to get an objective science of that.

OK, I promised to refute all these guys, but I don’t have an awful lot of time left, but let me refute a couple more of them.

I said that behaviorism ought to be one of the great embarrassments of our intellectual culture, because it’s refuted the moment you think about it. Your mental states are identical with your behavior? Well, think about the distinction between feeling a pain, and engaging in pain behavior. I mean, I won’t demonstrate pain behavior but I can tell you I am not having any pains right now. So it’s an obvious mistake.

Why did they make the mistake? The mistake was, and you go back and ready the literature on this, you can see this over and over, they think, if you accept the irreducible existence of consciousness, you’re giving up on science, you’re giving up on 300 years of human progress and human hope and all the rest of it.

And the message I want to leave you with is consciousness has to become accepted as a genuine biological phenomenon, as much subject to scientific analysis as any other phenomena in biology, or, for that matter, the rest of science.

Thank you very much.

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