Our shared condition -- consciousness
-
0:00 - 0:03I'm going to talk about consciousness.
-
0:03 - 0:04Why consciousness?
-
0:04 - 0:07Well, it's a curiously neglected subject,
-
0:07 - 0:10both in our scientific and our philosophical culture.
-
0:10 - 0:12Now why is that curious?
-
0:12 - 0:15Well, it is the most important aspect of our lives
-
0:15 - 0:17for a very simple, logical reason,
-
0:17 - 0:20namely, it's a necessary condition on anything
-
0:20 - 0:22being important in our lives that we're conscious.
-
0:22 - 0:25You care about science, philosophy, music, art, whatever --
-
0:25 - 0:29it's no good if you're a zombie or in a coma, right?
-
0:29 - 0:31So consciousness is number one.
-
0:31 - 0:34The second reason is that when people do
-
0:34 - 0:36get interested in it, as I think they should,
-
0:36 - 0:39they tend to say the most appalling things.
-
0:39 - 0:41And then, even when they're not saying appalling things
-
0:41 - 0:43and they're really trying to do serious research,
-
0:43 - 0:47well, it's been slow. Progress has been slow.
-
0:47 - 0:50When I first got interested in this, I thought, well,
-
0:50 - 0:52it's a straightforward problem in biology.
-
0:52 - 0:55Let's get these brain stabbers to get busy and figure out
-
0:55 - 0:56how it works in the brain.
-
0:56 - 0:57So I went over to UCSF and I talked to all
-
0:57 - 0:59the heavy-duty neurobiologists there,
-
0:59 - 1:01and they showed some impatience,
-
1:01 - 1:04as scientists often do when you ask them embarrassing questions.
-
1:04 - 1:08But the thing that struck me is, one guy said in exasperation,
-
1:08 - 1:10a very famous neurobiologist, he said, "Look,
-
1:10 - 1:14in my discipline it's okay to be interested in consciousness,
-
1:14 - 1:17but get tenure first. Get tenure first."
-
1:17 - 1:20Now I've been working on this for a long time.
-
1:20 - 1:22I think now you might actually get tenure
-
1:22 - 1:23by working on consciousness.
-
1:23 - 1:26If so, that's a real step forward.
-
1:26 - 1:29Okay, now why then is this curious reluctance
-
1:29 - 1:31and curious hostility to consciousness?
-
1:31 - 1:33Well, I think it's a combination of two features
-
1:33 - 1:35of our intellectual culture
-
1:35 - 1:38that like to think they're opposing each other
-
1:38 - 1:41but in fact they share a common set of assumptions.
-
1:41 - 1:45One feature is the tradition of religious dualism:
-
1:45 - 1:49Consciousness is not a part of the physical world.
-
1:49 - 1:51It's a part of the spiritual world.
-
1:51 - 1:52It belongs to the soul,
-
1:52 - 1:55and the soul is not a part of the physical world.
-
1:55 - 1:59That's the tradition of God, the soul and immortality.
-
1:59 - 2:01There's another tradition that thinks it's opposed to this
-
2:01 - 2:03but accepts the worst assumption.
-
2:03 - 2:07That tradition thinks that we are heavy-duty scientific materialists:
-
2:07 - 2:10Consciousness is not a part of the physical world.
-
2:10 - 2:13Either it doesn't exist at all, or it's something else,
-
2:13 - 2:16a computer program or some damn fool thing,
-
2:16 - 2:19but in any case it's not part of science.
-
2:19 - 2:21And I used to get in an argument that really gave me a stomachache.
-
2:21 - 2:23Here's how it went.
-
2:23 - 2:27Science is objective, consciousness is subjective,
-
2:27 - 2:30therefore there cannot be a science of consciousness.
-
2:30 - 2:36Okay, so these twin traditions are paralyzing us.
-
2:36 - 2:39It's very hard to get out of these twin traditions.
-
2:39 - 2:42And I have only one real message in this lecture,
-
2:42 - 2:46and that is, consciousness is a biological phenomenon
-
2:46 - 2:49like photosynthesis, digestion, mitosis --
-
2:49 - 2:53you know all the biological phenomena -- and once you accept that,
-
2:53 - 2:56most, though not all, of the hard problems
-
2:56 - 2:58about consciousness simply evaporate.
-
2:58 - 3:00And I'm going to go through some of them.
-
3:00 - 3:02Okay, now I promised you to tell you some
-
3:02 - 3:05of the outrageous things said about consciousness.
-
3:05 - 3:09One: Consciousness does not exist.
-
3:09 - 3:11It's an illusion, like sunsets.
-
3:11 - 3:16Science has shown sunsets and rainbows are illusions.
-
3:16 - 3:18So consciousness is an illusion.
-
3:18 - 3:21Two: Well, maybe it exists, but it's really something else.
-
3:21 - 3:25It's a computer program running in the brain.
-
3:25 - 3:29Three: No, the only thing that exists is really behavior.
-
3:29 - 3:32It's embarrassing how influential behaviorism was,
-
3:32 - 3:34but I'll get back to that.
-
3:34 - 3:36And four: Maybe consciousness exists,
-
3:36 - 3:38but it can't make any difference to the world.
-
3:38 - 3:41How could spirituality move anything?
-
3:41 - 3:43Now, whenever somebody tells me that, I think,
-
3:43 - 3:45you want to see spirituality move something?
-
3:45 - 3:49Watch. I decide consciously to raise my arm,
-
3:49 - 3:51and the damn thing goes up. (Laughter)
-
3:51 - 3:55Furthermore, notice this:
-
3:55 - 3:59We do not say, "Well, it's a bit like the weather in Geneva.
-
3:59 - 4:02Some days it goes up and some days it doesn't go up."
-
4:02 - 4:04No. It goes up whenever I damn well want it to.
-
4:04 - 4:06Okay. I'm going to tell you how that's possible.
-
4:06 - 4:10Now, I haven't yet given you a definition.
-
4:10 - 4:12You can't do this if you don't give a definition.
-
4:12 - 4:15People always say consciousness is very hard to define.
-
4:15 - 4:17I think it's rather easy to define
-
4:17 - 4:20if you're not trying to give a scientific definition.
-
4:20 - 4:22We're not ready for a scientific definition,
-
4:22 - 4:24but here's a common-sense definition.
-
4:24 - 4:26Consciousness consists of all those states of feeling
-
4:26 - 4:28or sentience or awareness.
-
4:28 - 4:32It begins in the morning when you wake up from a dreamless sleep,
-
4:32 - 4:35and it goes on all day until you fall asleep
-
4:35 - 4:38or die or otherwise become unconscious.
-
4:38 - 4:41Dreams are a form of consciousness on this definition.
-
4:41 - 4:44Now, that's the common-sense definition. That's our target.
-
4:44 - 4:47If you're not talking about that, you're not talking about consciousness.
-
4:47 - 4:51But they think, "Well, if that's it, that's an awful problem.
-
4:51 - 4:55How can such a thing exist as part of the real world?"
-
4:55 - 4:57And this, if you've ever had a philosophy course,
-
4:57 - 5:00this is known as the famous mind-body problem.
-
5:00 - 5:03I think that has a simple solution too. I'm going to give it to you.
-
5:03 - 5:07And here it is: All of our conscious states, without exception,
-
5:07 - 5:13are caused by lower-level neurobiological processes in the brain,
-
5:13 - 5:15and they are realized in the brain
-
5:15 - 5:17as higher-level or system features.
-
5:17 - 5:20It's about as mysterious as the liquidity of water.
-
5:20 - 5:24Right? The liquidity is not an extra juice squirted out
-
5:24 - 5:25by the H2O molecules.
-
5:25 - 5:28It's a condition that the system is in.
-
5:28 - 5:33And just as the jar full of water can go from liquid to solid
-
5:33 - 5:35depending on the behavior of the molecules,
-
5:35 - 5:38so your brain can go from a state of being conscious
-
5:38 - 5:40to a state of being unconscious,
-
5:40 - 5:43depending on the behavior of the molecules.
-
5:43 - 5:47The famous mind-body problem is that simple.
-
5:47 - 5:51All right? But now we get into some harder questions.
-
5:51 - 5:54Let's specify the exact features of consciousness,
-
5:54 - 5:57so that we can then answer those four objections
-
5:57 - 5:58that I made to it.
-
5:58 - 6:02Well, the first feature is, it's real and irreducible.
-
6:02 - 6:04You can't get rid of it.
-
6:04 - 6:08You see, the distinction between reality and illusion
-
6:08 - 6:11is the distinction between how things
-
6:11 - 6:15consciously seem to us and how they really are.
-
6:15 - 6:17It consciously seems like there's --
-
6:17 - 6:18I like the French "arc-en-ciel" —
-
6:18 - 6:21it seems like there's an arch in the sky,
-
6:21 - 6:24or it seems like the sun is setting over the mountains.
-
6:24 - 6:27It consciously seems to us, but that's not really happening.
-
6:27 - 6:29But for that distinction between
-
6:29 - 6:32how things consciously seem and how they really are,
-
6:32 - 6:36you can't make that distinction for the very existence of consciousness,
-
6:36 - 6:40because where the very existence of consciousness is concerned,
-
6:40 - 6:43if it consciously seems to you that you are conscious,
-
6:43 - 6:45you are conscious.
-
6:45 - 6:48I mean, if a bunch of experts come to me and say,
-
6:48 - 6:50"We are heavy-duty neurobiologists and we've done a study
-
6:50 - 6:53of you, Searle, and we're convinced you are not conscious,
-
6:53 - 6:55you are a very cleverly constructed robot,"
-
6:55 - 6:59I don't think, "Well, maybe these guys are right, you know?"
-
6:59 - 7:01I don't think that for a moment, because, I mean,
-
7:01 - 7:04Descartes may have made a lot of mistakes, but he was right about this.
-
7:04 - 7:07You cannot doubt the existence of your own consciousness.
-
7:07 - 7:09Okay, that's the first feature of consciousness.
-
7:09 - 7:11It's real and irreducible.
-
7:11 - 7:15You cannot get rid of it by showing that it's an illusion
-
7:15 - 7:18in a way that you can with other standard illusions.
-
7:18 - 7:20Okay, the second feature is this one
-
7:20 - 7:23that has been such a source of trouble to us,
-
7:23 - 7:25and that is, all of our conscious states
-
7:25 - 7:28have this qualitative character to them.
-
7:28 - 7:30There's something that it feels like to drink beer
-
7:30 - 7:33which is not what it feels like to do your income tax
-
7:33 - 7:36or listen to music, and this qualitative feel
-
7:36 - 7:39automatically generates a third feature,
-
7:39 - 7:43namely, conscious states are by definition subjective
-
7:43 - 7:46in the sense that they only exist as experienced
-
7:46 - 7:48by some human or animal subject,
-
7:48 - 7:50some self that experiences them.
-
7:50 - 7:52Maybe we'll be able to build a conscious machine.
-
7:52 - 7:54Since we don't know how our brains do it,
-
7:54 - 7:58we're not in a position, so far, to build a conscious machine.
-
7:58 - 8:01Okay. Another feature of consciousness
-
8:01 - 8:05is that it comes in unified conscious fields.
-
8:05 - 8:08So I don't just have the sight of the people in front of me
-
8:08 - 8:10and the sound of my voice and the weight of my shoes
-
8:10 - 8:13against the floor, but they occur to me
-
8:13 - 8:16as part of one single great conscious field
-
8:16 - 8:18that stretches forward and backward.
-
8:18 - 8:20That is the key to understanding
-
8:20 - 8:22the enormous power of consciousness.
-
8:22 - 8:25And we have not been able to do that in a robot.
-
8:25 - 8:28The disappointment of robotics derives from the fact
-
8:28 - 8:30that we don't know how to make a conscious robot,
-
8:30 - 8:33so we don't have a machine that can do this kind of thing.
-
8:33 - 8:36Okay, the next feature of consciousness,
-
8:36 - 8:39after this marvelous unified conscious field,
-
8:39 - 8:42is that it functions causally in our behavior.
-
8:42 - 8:45I gave you a scientific demonstration by raising my hand,
-
8:45 - 8:46but how is that possible?
-
8:46 - 8:50How can it be that this thought in my brain
-
8:50 - 8:52can move material objects?
-
8:52 - 8:54Well, I'll tell you the answer.
-
8:54 - 8:56I mean, we don't know the detailed answer,
-
8:56 - 8:59but we know the basic part of the answer, and that is,
-
8:59 - 9:01there is a sequence of neuron firings,
-
9:01 - 9:04and they terminate where the acetylcholine
-
9:04 - 9:07is secreted at the axon end-plates of the motor neurons.
-
9:07 - 9:09Sorry to use philosophical terminology here,
-
9:09 - 9:13but when it's secreted at the axon end-plates of the motor neurons,
-
9:13 - 9:16a whole lot of wonderful things happen in the ion channels
-
9:16 - 9:18and the damned arm goes up.
-
9:18 - 9:20Now, think of what I told you.
-
9:20 - 9:22One and the same event,
-
9:22 - 9:25my conscious decision to raise my arm
-
9:25 - 9:27has a level of description where it has all of these
-
9:27 - 9:30touchy-feely spiritual qualities.
-
9:30 - 9:32It's a thought in my brain, but at the same time,
-
9:32 - 9:34it's busy secreting acetylcholine
-
9:34 - 9:35and doing all sorts of other things
-
9:35 - 9:38as it makes its way from the motor cortex
-
9:38 - 9:41down through the nerve fibers in the arm.
-
9:41 - 9:45Now, what that tells us is that our traditional vocabularies
-
9:45 - 9:48for discussing these issues are totally obsolete.
-
9:48 - 9:51One and the same event has a level of description
-
9:51 - 9:54where it's neurobiological, and another level of description
-
9:54 - 9:57where it's mental, and that's a single event,
-
9:57 - 9:59and that's how nature works. That's how it's possible
-
9:59 - 10:02for consciousness to function causally.
-
10:02 - 10:05Okay, now with that in mind,
-
10:05 - 10:08with going through these various features of consciousness,
-
10:08 - 10:11let's go back and answer some of those early objections.
-
10:11 - 10:14Well, the first one I said was, consciousness doesn't exist,
-
10:14 - 10:16it's an illusion. Well, I've already answered that.
-
10:16 - 10:18I don't think we need to worry about that.
-
10:18 - 10:22But the second one had an incredible influence,
-
10:22 - 10:23and may still be around, and that is,
-
10:23 - 10:27"Well, if consciousness exists, it's really something else.
-
10:27 - 10:30It's really a digital computer program running in your brain
-
10:30 - 10:33and that's what we need to do to create consciousness
-
10:33 - 10:34is get the right program.
-
10:34 - 10:37Yeah, forget about the hardware. Any hardware will do
-
10:37 - 10:40provided it's rich enough and stable enough to carry the program."
-
10:40 - 10:43Now, we know that that's wrong.
-
10:43 - 10:46I mean, anybody who's thought about computers at all
-
10:46 - 10:48can see that that's wrong, because computation
-
10:48 - 10:51is defined as symbol manipulation,
-
10:51 - 10:53usually thought of as zeros as ones, but any symbols will do.
-
10:53 - 10:57You get an algorithm that you can program
-
10:57 - 11:00in a binary code, and that's the defining trait
-
11:00 - 11:02of the computer program.
-
11:02 - 11:06But we know that that's purely syntactical. That's symbolic.
-
11:06 - 11:10We know that actual human consciousness has something more than that.
-
11:10 - 11:13It's got a content in addition to the syntax.
-
11:13 - 11:14It's got a semantics.
-
11:14 - 11:17Now that argument, I made that argument 30 --
-
11:17 - 11:18oh my God, I don't want to think about it —
-
11:18 - 11:19more than 30 years ago,
-
11:19 - 11:22but there's a deeper argument implicit in what I've told you,
-
11:22 - 11:25and I want to tell you that argument briefly, and that is,
-
11:25 - 11:30consciousness creates an observer-independent reality.
-
11:30 - 11:33It creates a reality of money, property, government,
-
11:33 - 11:37marriage, CERN conferences,
-
11:37 - 11:40cocktail parties and summer vacations,
-
11:40 - 11:42and all of those are creations of consciousness.
-
11:42 - 11:45Their existence is observer-relative.
-
11:45 - 11:49It's only relative to conscious agents that a piece of paper
-
11:49 - 11:52is money or that a bunch of buildings is a university.
-
11:52 - 11:55Now, ask yourself about computation.
-
11:55 - 11:59Is that absolute, like force and mass and gravitational attraction?
-
11:59 - 12:01Or is it observer-relative?
-
12:01 - 12:05Well, some computations are intrinsic.
-
12:05 - 12:07I add two plus two to get four.
-
12:07 - 12:09That's going on no matter what anybody thinks.
-
12:09 - 12:12But when I haul out my pocket calculator
-
12:12 - 12:16and do the calculation, the only intrinsic phenomenon
-
12:16 - 12:19is the electronic circuit and its behavior.
-
12:19 - 12:21That's the only absolute phenomenon.
-
12:21 - 12:23All the rest is interpreted by us.
-
12:23 - 12:27Computation only exists relative to consciousness.
-
12:27 - 12:30Either a conscious agent is carrying out the computation,
-
12:30 - 12:33or he's got a piece of machinery that admits of a computational interpretation.
-
12:33 - 12:36Now that doesn't mean computation is arbitrary.
-
12:36 - 12:39I spent a lot of money on this hardware.
-
12:39 - 12:41But we have this persistent confusion
-
12:41 - 12:46between objectivity and subjectivity as features of reality
-
12:46 - 12:49and objectivity and subjectivity as features of claims.
-
12:49 - 12:53And the bottom line of this part of my talk is this:
-
12:53 - 12:56You can have a completely objective science,
-
12:56 - 12:59a science where you make objectively true claims,
-
12:59 - 13:03about a domain whose existence is subjective,
-
13:03 - 13:06whose existence is in the human brain
-
13:06 - 13:08consisting of subjective states of sentience
-
13:08 - 13:10or feeling or awareness.
-
13:10 - 13:14So the objection that you can't have an objective science of consciousness
-
13:14 - 13:18because it's subjective and science is objective, that's a pun.
-
13:18 - 13:21That's a bad pun on objectivity and subjectivity.
-
13:21 - 13:23You can make objective claims
-
13:23 - 13:27about a domain that is subjective in its mode of existence,
-
13:27 - 13:29and indeed that's what neurologists do.
-
13:29 - 13:31I mean, you have patients that actually suffer pains,
-
13:31 - 13:34and you try to get an objective science of that.
-
13:34 - 13:36Okay, I promised to refute all these guys,
-
13:36 - 13:38and I don't have an awful lot of time left,
-
13:38 - 13:40but let me refute a couple more of them.
-
13:40 - 13:42I said that behaviorism ought to be
-
13:42 - 13:45one of the great embarrassments of our intellectual culture,
-
13:45 - 13:48because it's refuted the moment you think about it.
-
13:48 - 13:51Your mental states are identical with your behavior?
-
13:51 - 13:54Well, think about the distinction between feeling a pain
-
13:54 - 13:56and engaging in pain behavior.
-
13:56 - 13:58I won't demonstrate pain behavior, but I can tell you
-
13:58 - 14:00I'm not having any pains right now.
-
14:00 - 14:04So it's an obvious mistake. Why did they make the mistake?
-
14:04 - 14:06The mistake was — and you can go back and read
-
14:06 - 14:08the literature on this, you can see this over and over —
-
14:08 - 14:12they think if you accept the irreducible existence
-
14:12 - 14:15of consciousness, you're giving up on science.
-
14:15 - 14:18You're giving up on 300 years of human progress
-
14:18 - 14:20and human hope and all the rest of it.
-
14:20 - 14:23And the message I want to leave you with is,
-
14:23 - 14:25consciousness has to become accepted
-
14:25 - 14:28as a genuine biological phenomenon,
-
14:28 - 14:30as much subject to scientific analysis
-
14:30 - 14:32as any other phenomenon in biology,
-
14:32 - 14:34or, for that matter, the rest of science.
-
14:34 - 14:36Thank you very much.
-
14:36 - 14:41(Applause)
- Title:
- Our shared condition -- consciousness
- Speaker:
- John Searle
- Description:
-
Philosopher John Searle lays out the case for studying human consciousness -- and systematically shoots down some of the common objections to taking it seriously. As we learn more about the brain processes that cause awareness, accepting that consciousness is a biological phenomenon is an important first step. And no, he says, consciousness is not a massive computer simulation. (Filmed at TEDxCERN.)
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDTalks
- Duration:
- 14:59
Krystian Aparta edited English subtitles for Our shared condition -- consciousness | ||
Thu-Huong Ha edited English subtitles for Our shared condition -- consciousness | ||
Thu-Huong Ha approved English subtitles for Our shared condition -- consciousness | ||
Thu-Huong Ha edited English subtitles for Our shared condition -- consciousness | ||
Thu-Huong Ha edited English subtitles for Our shared condition -- consciousness | ||
Morton Bast accepted English subtitles for Our shared condition -- consciousness | ||
Morton Bast edited English subtitles for Our shared condition -- consciousness | ||
Joseph Geni edited English subtitles for Our shared condition -- consciousness |