Our shared condition -- consciousness
-
0:00 - 0:03I'm going to talk about consciousness.
-
0:03 - 0:05Why consciousness?
-
0:05 - 0:07Well, it's a curiously neglected subject,
-
0:07 - 0:11both in our scientific
and our philosophical culture. -
0:11 - 0:12Now why is that curious?
-
0:12 - 0:16Well, it is the most important
aspect of our lives -
0:16 - 0:18for a very simple, logical reason,
-
0:18 - 0:20namely, it's a necessary
condition on anything -
0:20 - 0:23being important in our lives
that we're conscious. -
0:23 - 0:26You care about science, philosophy,
music, art, whatever -- -
0:26 - 0:29it's no good if you're
a zombie or in a coma, right? -
0:29 - 0:32So consciousness is number one.
-
0:32 - 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 - 0:42And then, even when they're
not saying appalling things -
0:42 - 0:44and they're really trying
to do serious research, -
0:44 - 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 - 0:53it's a straightforward problem in biology.
-
0:53 - 0:55Let's get these brain stabbers
to get busy and figure out -
0:55 - 0:56how it works in the brain.
-
0:56 - 0:58So I went over to UCSF and I talked to all
-
0:58 - 1:00the heavy-duty neurobiologists there,
-
1:00 - 1:01and they showed some impatience,
-
1:01 - 1:05as scientists often do when you
ask them embarrassing questions. -
1:05 - 1:09But the thing that struck me is,
one guy said in exasperation, -
1:09 - 1:11a very famous neurobiologist,
he said, "Look, -
1:11 - 1:14in my discipline it's okay to be
interested in consciousness, -
1:14 - 1:18but get tenure first. Get tenure first."
-
1:18 - 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 - 1:24by working on consciousness.
-
1:24 - 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 - 1:34Well, I think it's a combination
of two features -
1:34 - 1:36of our intellectual culture
-
1:36 - 1:38that like to think they're
opposing each other -
1:38 - 1:42but in fact they share
a common set of assumptions. -
1:42 - 1:46One feature is the tradition
of religious dualism: -
1:46 - 1:49Consciousness is not a part
of the physical world. -
1:49 - 1:51It's a part of the spiritual world.
-
1:51 - 1:53It belongs to the soul,
-
1:53 - 1:56and the soul is not a part
of the physical world. -
1:56 - 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 - 2:11Consciousness is not a part
of the physical world. -
2:11 - 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 - 2:37Okay, so these twin
traditions are paralyzing us. -
2:37 - 2:40It's very hard to get
out of these twin traditions. -
2:40 - 2:43And I have only one real
message in this lecture, -
2:43 - 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 - 3:03Okay, now I promised you to tell you some
-
3:03 - 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 - 3:22Two: Well, maybe it exists,
but it's really something else. -
3:22 - 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 - 3:33It's embarrassing how influential
behaviorism was, -
3:33 - 3:34but I'll get back to that.
-
3:34 - 3:37And four: Maybe consciousness exists,
-
3:37 - 3:39but it can't make
any difference to the world. -
3:39 - 3:42How could spirituality move anything?
-
3:42 - 3:44Now, whenever somebody
tells me that, I think, -
3:44 - 3:46you want to see spirituality
move something? -
3:46 - 3:49Watch. I decide consciously
to raise my arm, -
3:49 - 3:52and the damn thing goes up. (Laughter)
-
3:52 - 3:55Furthermore, notice this:
-
3:56 - 3:59We do not say, "Well, it's a bit
like the weather in Geneva. -
4:00 - 4:02Some days it goes up and some days
it doesn't go up." -
4:02 - 4:05No. It goes up whenever
I damn well want it to. -
4:05 - 4:07Okay. I'm going to tell
you how that's possible. -
4:07 - 4:11Now, I haven't yet given you a definition.
-
4:11 - 4:13You can't do this if you
don't give a definition. -
4:13 - 4:16People always say consciousness
is very hard to define. -
4:16 - 4:18I think it's rather easy to define
-
4:18 - 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 - 4:27Consciousness consists
of all those states of feeling -
4:27 - 4:29or sentience or awareness.
-
4:29 - 4:33It begins in the morning when you
wake up from a dreamless sleep, -
4:33 - 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 - 4:48If you're not talking about that,
you're not talking about consciousness. -
4:48 - 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 - 4:58And this, if you've ever
had a philosophy course, -
4:58 - 5:00this is known as the famous
mind-body problem. -
5:00 - 5:04I think that has a simple solution too.
I'm going to give it to you. -
5:04 - 5:08And here it is: All of our conscious
states, without exception, -
5:08 - 5:13are caused by lower-level
neurobiological processes in the brain, -
5:13 - 5:15and they are realized in the brain
-
5:15 - 5:18as higher-level or system features.
-
5:18 - 5:21It's about as mysterious
as the liquidity of water. -
5:21 - 5:24Right? The liquidity is not
an extra juice squirted out -
5:24 - 5:26by the H2O molecules.
-
5:26 - 5:29It's a condition that the system is in.
-
5:29 - 5:34And just as the jar full of water
can go from liquid to solid -
5:34 - 5:36depending on the behavior
of the molecules, -
5:36 - 5:39so your brain can go
from a state of being conscious -
5:39 - 5:41to a state of being unconscious,
-
5:41 - 5:44depending on the behavior
of the molecules. -
5:44 - 5:48The famous mind-body
problem is that simple. -
5:48 - 5:51All right? But now we get
into some harder questions. -
5:51 - 5:55Let's specify the exact
features of consciousness, -
5:55 - 5:57so that we can then answer
those four objections -
5:57 - 5:58that I made to it.
-
5:58 - 6:03Well, the first feature is,
it's real and irreducible. -
6:03 - 6:05You can't get rid of it.
-
6:05 - 6:09You see, the distinction
between reality and illusion -
6:09 - 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 - 6:19I like the French "arc-en-ciel" —
-
6:19 - 6:21it seems like there's an arch in the sky,
-
6:21 - 6:25or it seems like the sun
is setting over the mountains. -
6:25 - 6:28It consciously seems to us,
but that's not really happening. -
6:28 - 6:30But for that distinction between
-
6:30 - 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 - 6:51"We are heavy-duty neurobiologists
and we've done a study -
6:51 - 6:54of you, Searle, and we're
convinced you are not conscious, -
6:54 - 6:56you are a very cleverly
constructed robot," -
6:56 - 6:59I don't think, "Well, maybe these
guys are right, you know?" -
6:59 - 7:02I don't think that for a moment,
because, I mean, -
7:02 - 7:05Descartes may have made a lot
of mistakes, but he was right about this. -
7:05 - 7:08You cannot doubt the existence
of your own consciousness. -
7:08 - 7:10Okay, that's the first
feature of consciousness. -
7:10 - 7:12It's real and irreducible.
-
7:12 - 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 - 7:21Okay, the second feature is this one
-
7:21 - 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 - 7:31There's something that it
feels like to drink beer -
7:31 - 7:34which is not what it feels
like to do your income tax -
7:34 - 7:37or listen to music,
and this qualitative feel -
7:37 - 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 - 7:53Maybe we'll be able to build
a conscious machine. -
7:53 - 7:55Since we don't know how our brains do it,
-
7:55 - 7:59we're not in a position, so far,
to build a conscious machine. -
7:59 - 8:02Okay. Another feature of consciousness
-
8:02 - 8:06is that it comes in unified
conscious fields. -
8:06 - 8:08So I don't just have the sight
of the people in front of me -
8:08 - 8:11and the sound of my voice
and the weight of my shoes -
8:11 - 8:13against the floor, but they occur to me
-
8:13 - 8:17as part of one single
great conscious field -
8:17 - 8:19that stretches forward and backward.
-
8:19 - 8:20That is the key to understanding
-
8:20 - 8:23the enormous power of consciousness.
-
8:23 - 8:26And we have not been able
to do that in a robot. -
8:26 - 8:28The disappointment of robotics
derives from the fact -
8:28 - 8:31that we don't know how to make
a conscious robot, -
8:31 - 8:34so we don't have a machine
that can do this kind of thing. -
8:34 - 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 - 8:47but how is that possible?
-
8:47 - 8:51How can it be that this
thought in my brain -
8:51 - 8:53can move material objects?
-
8:53 - 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 - 9:05and they terminate where the acetylcholine
-
9:05 - 9:07is secreted at the axon
end-plates of the motor neurons. -
9:07 - 9:09Sorry to use philosophical
terminology here, -
9:10 - 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 - 9:28has a level of description
where it has all of these -
9:28 - 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 - 9:36and doing all sorts of other things
-
9:36 - 9:39as it makes its way from the motor cortex
-
9:39 - 9:41down through the nerve fibers in the arm.
-
9:41 - 9:45Now, what that tells us
is that our traditional vocabularies -
9:45 - 9:49for discussing these issues
are totally obsolete. -
9:49 - 9:52One and the same event has
a level of description -
9:52 - 9:55where it's neurobiological,
and another level of description -
9:55 - 9:57where it's mental,
and that's a single event, -
9:57 - 10:00and that's how nature works.
That's how it's possible -
10:00 - 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 - 10:15Well, the first one I said was,
consciousness doesn't exist, -
10:15 - 10:17it's an illusion. Well,
I've already answered that. -
10:17 - 10:19I don't think we need to worry about that.
-
10:19 - 10:22But the second one had
an incredible influence, -
10:22 - 10:24and may still be around, and that is,
-
10:24 - 10:27"Well, if consciousness exists,
it's really something else. -
10:27 - 10:31It's really a digital computer
program running in your brain -
10:31 - 10:33and that's what we need to do
to create consciousness -
10:33 - 10:35is get the right program.
-
10:35 - 10:37Yeah, forget about the hardware.
Any hardware will do -
10:37 - 10:41provided it's rich enough and stable
enough to carry the program." -
10:41 - 10:43Now, we know that that's wrong.
-
10:43 - 10:46I mean, anybody who's thought
about computers at all -
10:46 - 10:49can see that that's wrong,
because computation -
10:49 - 10:51is defined as symbol manipulation,
-
10:51 - 10:54usually thought of as zeros
as ones, but any symbols will do. -
10:54 - 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 - 11:15It's got a semantics.
-
11:15 - 11:17Now that argument, I made
that argument 30 -- -
11:17 - 11:19oh my God, I don't want
to think about it — -
11:19 - 11:20more than 30 years ago,
-
11:20 - 11:23but there's a deeper argument
implicit in what I've told you, -
11:23 - 11:26and I want to tell you that argument
briefly, and that is, -
11:26 - 11:30consciousness creates
an observer-independent reality. -
11:30 - 11:34It creates a reality of money,
property, government, -
11:34 - 11:38marriage, CERN conferences,
-
11:38 - 11:40cocktail parties and summer vacations,
-
11:40 - 11:43and all of those are creations
of consciousness. -
11:43 - 11:46Their existence is observer-relative.
-
11:46 - 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 - 11:56Now, ask yourself about computation.
-
11:56 - 12:00Is that absolute, like force and mass
and gravitational attraction? -
12:00 - 12:02Or is it observer-relative?
-
12:02 - 12:05Well, some computations are intrinsic.
-
12:05 - 12:07I add two plus two to get four.
-
12:07 - 12:10That's going on no matter
what anybody thinks. -
12:10 - 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 - 12:34or he's got a piece of machinery that admits
of a computational interpretation. -
12:34 - 12:37Now that doesn't mean
computation is arbitrary. -
12:37 - 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 - 12:50and objectivity and subjectivity
as features of claims. -
12:50 - 12:53And the bottom line of this
part of my talk is this: -
12:53 - 12:57You can have a completely
objective science, -
12:57 - 13:00a science where you make
objectively true claims, -
13:00 - 13:03about a domain whose existence
is subjective, -
13:03 - 13:06whose existence is in the human brain
-
13:06 - 13:09consisting of subjective
states of sentience -
13:09 - 13:10or feeling or awareness.
-
13:10 - 13:15So the objection that you can't have
an objective science of consciousness -
13:15 - 13:19because it's subjective and science
is objective, that's a pun. -
13:19 - 13:21That's a bad pun on objectivity
and subjectivity. -
13:21 - 13:24You can make objective claims
-
13:24 - 13:28about a domain that is subjective
in its mode of existence, -
13:28 - 13:29and indeed that's what neurologists do.
-
13:29 - 13:32I mean, you have patients
that actually suffer pains, -
13:32 - 13:35and you try to get
an objective science of that. -
13:35 - 13:37Okay, I promised to refute all these guys,
-
13:37 - 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 - 13:46one of the great embarrassments
of our intellectual culture, -
13:46 - 13:49because it's refuted
the moment you think about it. -
13:49 - 13:51Your mental states are identical
with your behavior? -
13:51 - 13:55Well, think about the distinction
between feeling a pain -
13:55 - 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 - 14:09the literature on this, you
can see this over and over — -
14:09 - 14:13they think if you accept
the irreducible existence -
14:13 - 14:15of consciousness, you're
giving up on science. -
14:16 - 14:19You're giving up on 300
years of human progress -
14:19 - 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 - 14:26consciousness has to become accepted
-
14:26 - 14:28as a genuine biological phenomenon,
-
14:28 - 14:31as much subject to scientific analysis
-
14:31 - 14:33as any other phenomenon in biology,
-
14:33 - 14:35or, for that matter, the rest of science.
-
14:35 - 14:36Thank you very much.
-
14:36 - 14:42(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 |