full transcript

From the Ted Talk by John Searle: Our shared condition -- consciousness

Unscramble the Blue Letters

I'm going to talk about consciousness. Why consciousness? Well, it's a curiously nelcegted subject, both in our scientific and our philosophical culture. Now why is that ciruous? Well, it is the most important aspect of our lives for a very simple, logical reason, namely, it's a necessary condition on anything being important in our lievs that we're conscious. You care about science, phipslhooy, music, art, whatever — it's no good if you're a zombie or in a coma, right? So consciousness is number one. The second raseon is that when people do get interested in it, as I think they should, they tend to say the most appalling things. And then, even when they're not saying appalling things and they're really trying to do serious research, well, it's been slow. Progress has been slow. When I first got interested in this, I thought, well, it's a straightforward problem in biology. Let's get these brain stabbers to get busy and figure out how it works in the brain. So I went over to UCSF and I talked to all the heavy-duty neurobiologists there, and they showed some impatience, as scientists often do when you ask them esirmsaabnrg questions. But the thing that struck me is, one guy said in erosapatiexn, a very famous nriobiloseuogt, he said, "Look, in my discipline it's okay to be irtenseted in consciousness, but get tenure first. Get tenure first." Now I've been working on this for a long time. I think now you might actually get tenure by working on consciousness. If so, that's a real step forward. Okay, 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're opposing each other but in fact they share a common set of assumptions. One futreae is the tradition of religious dualism: Consciousness is not a part of the physical wrlod. It's a 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's another tradition that thinks it's opposed to this but accepts the worst aipumosstn. That tradition thinks that we are heavy-duty scientific materialists: cnuosoesicsns is not a part of the physical world. Either it doesn't esixt at all, or it's something else, a cuopemtr 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 sahaccmhtoe. Here's how it went. Science is objective, consciousness is subjective, therefore there cannot be a scecine of consciousness. Okay, so these twin traditions are plnrizaayg us. It's very hard to get out of these twin traditions. And I have only one real mgssaee in this lecture, and that is, consciousness is a biological ponnehemon like photosynthesis, digestion, mitosis — you know all the biological phenomena — and once you accept that, most, though not all, of the hard problems about consciousness simply evaporate. And I'm going to go through some of them. Okay, now I promised you to tell you some of the outrageous things said about consciousness. One: Consciousness does not exist. It's an illusion, like sunsets. Science has shown sunsets and rainbows are illusions. So consciousness is an illusion. Two: Well, maybe it exists, but it's 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 iulnnieaftl behaviorism was, but I'll get back to that. And four: Maybe consciousness exists, but it can't make any drceinfefe to the world. How could spirituality move anything? Now, whenever somebody tells me that, I think, you want to see sapiutilrity move something? Watch. I decide consciously to rsaie my arm, and the damn thing goes up. (Laughter) 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 whenever I damn well want it to. Okay. I'm going to tell you how that's 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's rather easy to deifne if you're not trying to give a scientific definition. We're not ready for a scientific definition, but here's a common-sense definition. Consciousness consists of all those states of feeling or sentience or awareness. It begins in the mnoirng when you wake up from a dreamless selep, 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 dioietnfin. That's our target. If you're not tilnakg about that, you're not talking about consciousness. But they think, "Well, if that's it, that's an awful problem. How can such a thing exist as part of the real world?" And this, if you've ever had a philosophy course, this is known as the famous mind-body problem. I think that has a simple solution too. I'm going to give it to you. And here it is: All of our conscious states, without etixcpeon, are caused by lower-level neurobiological pceoessrs in the brain, and they are realized in the biran as higher-level or system features. It's about as mysterious as the liquidity of waetr. 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 sloid depending on the behavior of the molecules, so your brain can go from a state of being conscious to a state of being uniosnocucs, depending on the behavior of the molecules. The famous mind-body problem is that simple. All right? But now we get into some harder qsuentois. Let's specify the eaxct features of consciousness, so that we can then answer those four objections that I made to it. Well, the first feature is, it's 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. It consciously seems like there's — I like the French "arc-en-ciel" — it seems like there's an arch in the sky, or it seems like the sun is setting over the mountains. It cinosusocly 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 dnttsoiciin 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 erxepts come to me and say, "We are heavy-duty nroeoisiutoglbs and we've done a study of you, Searle, and we're convinced you are not conscious, you are a very cleverly cutrtencosd robot," I don't think, "Well, maybe these guys are right, you know?" I don't think that for a menmot, because, I mean, Descartes may have made a lot of mkeasits, but he was right about this. You cannot doubt the existence of your own consciousness. Okay, that's the first feature of consciousness. It's real and irreducible. You cannot get rid of it by showing that it's an ilioslun in a way that you can with other standard illusions. Okay, the second feature is this one that has been such a source of trouble to us, and that is, all of our cscoionus settas have this qualitative character to them. There's something that it feels like to drink beer which is not what it feels like to do your income tax or listen to music, and this qualitative feel 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 subject, some self that experiences them. Maybe we'll be able to build a conscious machine. Since we don't know how our brains do it, we're not in a 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 the people in front of me and the sonud of my voice and the weight of my shoes against the floor, but they occur to me as part of one sglnie great conscious field that stretches forward and backward. That is the key to understanding the enurooms 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 rboot, so we don't have a machine that can do this kind of thing. Okay, the next feature of consciousness, after this mervolaus 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 mtareail ojebtcs? Well, I'll tell you the answer. I mean, we don't know the deeltaid answer, but we know the basic part of the answer, and that is, there is a sequence of nuoern fiingrs, and they terminate where the acetylcholine is secreted at the axon end-plates of the motor neurons. Sorry to use phpclioosahil tnooimrelgy here, but when it's sctreeed at the axon end-plates of the mtoor neurons, a whole lot of wonderful things happen in the ion cahnenls and the damned arm goes up. Now, think of what I told you. One and the same envet, 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 coretx down through the nerve fibers in the arm. Now, what that tells us is that our triitaaodnl vocabularies for discussing these isesus 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 fonuitcn causally. Okay, now with that in mind, with going through these various features of consciousness, let's go back and aswner some of those early ooncteijbs. 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 wrroy about that. But the second one had an incredible influence, and may still be around, and that is, "Well, 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. Yeah, forget about the hardware. Any hardware will do provided it's rich enough and sblate enough to carry the pgarrom." 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 symobl manipulation, usually thought of as zeros as ones, 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 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 that argument, I made that argument 30 — oh my God, I don't want to think about it — more than 30 years ago, but there's a deeper argument implicit in what I've told you, and I want to tell you that aegnurmt briefly, and that is, consciousness cetares an observer-independent reality. It creates a reality of money, prpetroy, government, marriage, CERN cencfreoens, cctkioal 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 mneoy or that a bunch of buildings is a usieintrvy. Now, ask yourself 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 haul out my pocket calculator and do the calculation, the only intrinsic phenomenon is the electronic circuit and its behavior. That's the only atusbole phenomenon. All the rest is iererentptd by us. Computation only exists relative to consciousness. Either a conscious agent is carrying out the computation, or he's got a piece of machinery that admits of a caoiautmtnpol interpretation. Now that doesn't mean computation is arbitrary. I spent a lot of money on this hardware. But we have this persistent counfison between objectivity and subjectivity as features of reality and objectivity and subjectivity as fauetres 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 ecixenste is in the human brain cnstosinig of subjective states of sentience or feeling or awareness. So the objection that you can't have an ojbecvite 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 netoolisugrs do. I mean, you have patients that actually suffer pains, and you try to get an objective science of that. Okay, I promised to refute all these guys, and I don't have an awful lot of time left, but let me rutefe a couple more of them. I said that behaviorism ought to be one of the great erbamsertmnass of our intellectual culture, because it's refuted the moment you think about it. Your mental states are identical with your beavohir? Well, think about the distinction between feeling a pain and engaging in pain behavior. I won't doaenstrmte pain behavior, but I can tell you I'm not having any pains right now. So it's an obvious mistake. Why did they make the mistake? The mistake was — and you can go back and read the literature on this, you can see this over and over — they think if you aepcct the ieidrclubre existence of consciousness, you're giving up on science. You're giving up on 300 years of human progress and huamn hope and all the rest of it. And the message I want to leave you with is, consciousness has to become acepetcd as a genuine biological phenomenon, as much subject to scientific analysis as any other phenomenon in biology, or, for that matter, the rest of science. Thank you very much. (Applause)

Open Cloze

I'm going to talk about consciousness. Why consciousness? Well, it's a curiously _________ subject, both in our scientific and our philosophical culture. Now why is that _______? Well, it is the most important aspect of our lives for a very simple, logical reason, namely, it's a necessary condition on anything being important in our _____ that we're conscious. You care about science, __________, music, art, whatever — it's no good if you're a zombie or in a coma, right? So consciousness is number one. The second ______ is that when people do get interested in it, as I think they should, they tend to say the most appalling things. And then, even when they're not saying appalling things and they're really trying to do serious research, well, it's been slow. Progress has been slow. When I first got interested in this, I thought, well, it's a straightforward problem in biology. Let's get these brain stabbers to get busy and figure out how it works in the brain. So I went over to UCSF and I talked to all the heavy-duty neurobiologists there, and they showed some impatience, as scientists often do when you ask them ____________ questions. But the thing that struck me is, one guy said in ____________, a very famous ______________, he said, "Look, in my discipline it's okay to be __________ in consciousness, but get tenure first. Get tenure first." Now I've been working on this for a long time. I think now you might actually get tenure by working on consciousness. If so, that's a real step forward. Okay, 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're opposing each other but in fact they share a common set of assumptions. One _______ is the tradition of religious dualism: Consciousness is not a part of the physical _____. It's a 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's another tradition that thinks it's opposed to this but accepts the worst __________. That tradition thinks that we are heavy-duty scientific materialists: _____________ is not a part of the physical world. Either it doesn't _____ at all, or it's something else, a ________ 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 ___________. Here's how it went. Science is objective, consciousness is subjective, therefore there cannot be a _______ of consciousness. Okay, so these twin traditions are __________ us. It's very hard to get out of these twin traditions. And I have only one real _______ in this lecture, and that is, consciousness is a biological __________ like photosynthesis, digestion, mitosis — you know all the biological phenomena — and once you accept that, most, though not all, of the hard problems about consciousness simply evaporate. And I'm going to go through some of them. Okay, now I promised you to tell you some of the outrageous things said about consciousness. One: Consciousness does not exist. It's an illusion, like sunsets. Science has shown sunsets and rainbows are illusions. So consciousness is an illusion. Two: Well, maybe it exists, but it's 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 ___________ behaviorism was, but I'll get back to that. And four: Maybe consciousness exists, but it can't make any __________ to the world. How could spirituality move anything? Now, whenever somebody tells me that, I think, you want to see ____________ move something? Watch. I decide consciously to _____ my arm, and the damn thing goes up. (Laughter) 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 whenever I damn well want it to. Okay. I'm going to tell you how that's 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's rather easy to ______ if you're not trying to give a scientific definition. We're not ready for a scientific definition, but here's a common-sense definition. Consciousness consists of all those states of feeling or sentience or awareness. It begins in the _______ when you wake up from a dreamless _____, 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 __________. That's our target. If you're not _______ about that, you're not talking about consciousness. But they think, "Well, if that's it, that's an awful problem. How can such a thing exist as part of the real world?" And this, if you've ever had a philosophy course, this is known as the famous mind-body problem. I think that has a simple solution too. I'm going to give it to you. And here it is: All of our conscious states, without _________, are caused by lower-level neurobiological _________ in the brain, and they are realized in the _____ as higher-level or system features. It's about as mysterious as the liquidity of _____. 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 _____ depending on the behavior of the molecules, so your brain can go from a state of being conscious to a state of being ___________, depending on the behavior of the molecules. The famous mind-body problem is that simple. All right? But now we get into some harder _________. Let's specify the _____ features of consciousness, so that we can then answer those four objections that I made to it. Well, the first feature is, it's 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. It consciously seems like there's — I like the French "arc-en-ciel" — it seems like there's an arch in the sky, or it seems like the sun is setting over the mountains. It ___________ 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 ___________ 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 _______ come to me and say, "We are heavy-duty _______________ and we've done a study of you, Searle, and we're convinced you are not conscious, you are a very cleverly ___________ robot," I don't think, "Well, maybe these guys are right, you know?" I don't think that for a ______, because, I mean, Descartes may have made a lot of ________, but he was right about this. You cannot doubt the existence of your own consciousness. Okay, that's the first feature of consciousness. It's real and irreducible. You cannot get rid of it by showing that it's an ________ in a way that you can with other standard illusions. Okay, the second feature is this one that has been such a source of trouble to us, and that is, all of our _________ ______ have this qualitative character to them. There's something that it feels like to drink beer which is not what it feels like to do your income tax or listen to music, and this qualitative feel 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 subject, some self that experiences them. Maybe we'll be able to build a conscious machine. Since we don't know how our brains do it, we're not in a 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 the people in front of me and the _____ of my voice and the weight of my shoes against the floor, but they occur to me as part of one ______ great conscious field that stretches forward and backward. That is the key to understanding the ________ 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 _____, so we don't have a machine that can do this kind of thing. Okay, the next feature of consciousness, after this _________ 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 ________ _______? Well, I'll tell you the answer. I mean, we don't know the ________ answer, but we know the basic part of the answer, and that is, there is a sequence of ______ _______, and they terminate where the acetylcholine is secreted at the axon end-plates of the motor neurons. Sorry to use _____________ ___________ here, but when it's ________ at the axon end-plates of the _____ neurons, a whole lot of wonderful things happen in the ion ________ and the damned arm goes up. Now, think of what I told you. One and the same _____, 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 ______ down through the nerve fibers in the arm. Now, what that tells us is that our ___________ vocabularies for discussing these ______ 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 ________ causally. Okay, now with that in mind, with going through these various features of consciousness, let's go back and ______ some of those early __________. 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 _____ about that. But the second one had an incredible influence, and may still be around, and that is, "Well, 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. Yeah, forget about the hardware. Any hardware will do provided it's rich enough and ______ enough to carry the _______." 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 ______ manipulation, usually thought of as zeros as ones, 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 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 that argument, I made that argument 30 — oh my God, I don't want to think about it — more than 30 years ago, but there's a deeper argument implicit in what I've told you, and I want to tell you that ________ briefly, and that is, consciousness _______ an observer-independent reality. It creates a reality of money, ________, government, marriage, CERN ___________, ________ 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 _____ or that a bunch of buildings is a __________. Now, ask yourself 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 haul out my pocket calculator and do the calculation, the only intrinsic phenomenon is the electronic circuit and its behavior. That's the only ________ phenomenon. All the rest is ___________ by us. Computation only exists relative to consciousness. Either a conscious agent is carrying out the computation, or he's got a piece of machinery that admits of a _____________ interpretation. Now that doesn't mean computation is arbitrary. I spent a lot of money on this hardware. But we have this persistent _________ between objectivity and subjectivity as features of reality and objectivity and subjectivity as ________ 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 _________ is in the human brain __________ of subjective states of sentience or feeling or awareness. So the objection that you can't have an _________ 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 ____________ do. I mean, you have patients that actually suffer pains, and you try to get an objective science of that. Okay, I promised to refute all these guys, and I don't have an awful lot of time left, but let me ______ a couple more of them. I said that behaviorism ought to be one of the great ______________ of our intellectual culture, because it's refuted the moment you think about it. Your mental states are identical with your ________? Well, think about the distinction between feeling a pain and engaging in pain behavior. I won't ___________ pain behavior, but I can tell you I'm not having any pains right now. So it's an obvious mistake. Why did they make the mistake? The mistake was — and you can go back and read the literature on this, you can see this over and over — they think if you ______ the ___________ existence of consciousness, you're giving up on science. You're giving up on 300 years of human progress and _____ hope and all the rest of it. And the message I want to leave you with is, consciousness has to become ________ as a genuine biological phenomenon, as much subject to scientific analysis as any other phenomenon in biology, or, for that matter, the rest of science. Thank you very much. (Applause)

Solution

  1. stable
  2. event
  3. marvelous
  4. neurobiologist
  5. objections
  6. answer
  7. traditional
  8. difference
  9. features
  10. money
  11. sound
  12. philosophical
  13. distinction
  14. exasperation
  15. human
  16. neuron
  17. robot
  18. consciousness
  19. spirituality
  20. conferences
  21. consisting
  22. brain
  23. definition
  24. solid
  25. neglected
  26. detailed
  27. refute
  28. enormous
  29. channels
  30. firings
  31. influential
  32. cortex
  33. single
  34. sleep
  35. argument
  36. program
  37. objective
  38. accept
  39. symbol
  40. constructed
  41. mistakes
  42. secreted
  43. interested
  44. neurobiologists
  45. stomachache
  46. lives
  47. issues
  48. embarrassing
  49. morning
  50. raise
  51. terminology
  52. embarrassments
  53. computational
  54. curious
  55. absolute
  56. consciously
  57. conscious
  58. interpreted
  59. function
  60. reason
  61. behavior
  62. science
  63. paralyzing
  64. cocktail
  65. philosophy
  66. processes
  67. world
  68. property
  69. message
  70. confusion
  71. material
  72. talking
  73. neurologists
  74. computer
  75. exception
  76. phenomenon
  77. water
  78. moment
  79. states
  80. accepted
  81. unconscious
  82. assumption
  83. exact
  84. define
  85. motor
  86. university
  87. exist
  88. creates
  89. irreducible
  90. demonstrate
  91. experts
  92. worry
  93. objects
  94. feature
  95. questions
  96. illusion
  97. existence

Original Text

I'm going to talk about consciousness. Why consciousness? Well, it's a curiously neglected subject, both in our scientific and our philosophical culture. Now why is that curious? Well, it is the most important aspect of our lives for a very simple, logical reason, namely, it's a necessary condition on anything being important in our lives that we're conscious. You care about science, philosophy, music, art, whatever — it's no good if you're a zombie or in a coma, right? So consciousness is number one. The second reason is that when people do get interested in it, as I think they should, they tend to say the most appalling things. And then, even when they're not saying appalling things and they're really trying to do serious research, well, it's been slow. Progress has been slow. When I first got interested in this, I thought, well, it's a straightforward problem in biology. Let's get these brain stabbers to get busy and figure out how it works in the brain. So I went over to UCSF and I talked to all the heavy-duty neurobiologists there, and they showed some impatience, as scientists often do when you ask them embarrassing questions. But the thing that struck me is, one guy said in exasperation, a very famous neurobiologist, he said, "Look, in my discipline it's okay to be interested in consciousness, but get tenure first. Get tenure first." Now I've been working on this for a long time. I think now you might actually get tenure by working on consciousness. If so, that's a real step forward. Okay, 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're opposing each other but in fact they share a common set of assumptions. One feature is the tradition of religious dualism: Consciousness is not a part of the physical world. It's a 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's another tradition that thinks it's opposed to this but accepts the worst assumption. That tradition thinks that we are heavy-duty scientific materialists: Consciousness is not a part of the physical world. Either it doesn't exist at all, or it's 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's how it went. Science is objective, consciousness is subjective, therefore there cannot be a science of consciousness. Okay, so these twin traditions are paralyzing us. 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 the biological phenomena — and once you accept that, most, though not all, of the hard problems about consciousness simply evaporate. And I'm going to go through some of them. Okay, now I promised you to tell you some of the outrageous things said about consciousness. One: Consciousness does not exist. It's an illusion, like sunsets. Science has shown sunsets and rainbows are illusions. So consciousness is an illusion. Two: Well, maybe it exists, but it's 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'll get back to that. And four: Maybe consciousness exists, but it can't make any difference to the world. How could spirituality move anything? Now, whenever somebody tells me that, I think, you want to see spirituality move something? Watch. I decide consciously to raise my arm, and the damn thing goes up. (Laughter) 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 whenever I damn well want it to. Okay. I'm going to tell you how that's 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's rather easy to define if you're not trying to give a scientific definition. We're not ready for a scientific definition, but here's a common-sense definition. Consciousness consists of all those states of feeling or sentience 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're not talking about that, you're not talking about consciousness. But they think, "Well, if that's it, that's an awful problem. How can such a thing exist as part of the real world?" And this, if you've ever had a philosophy course, this is known as the famous mind-body problem. I think that has a simple solution too. I'm 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's 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's 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. It consciously seems like there's — I like the French "arc-en-ciel" — 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 of you, Searle, and we're convinced you are not conscious, you are a very cleverly constructed robot," I don't think, "Well, maybe these guys are right, you know?" 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. Okay, that's the first feature of consciousness. It's 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. Okay, 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's something that it feels like to drink beer which is not what it feels like to do your income tax or listen to music, and this qualitative feel 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 subject, some self that experiences them. Maybe we'll be able to build a conscious machine. Since we don't know how our brains do it, we're not in a 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 the 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. Okay, 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'll 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 is a sequence 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's 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 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 nerve fibers in 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. Okay, 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, "Well, 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. Yeah, 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 zeros as ones, 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 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 that argument, I made that argument 30 — oh my God, I don't want to think about it — more than 30 years ago, but there's 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 money or that a bunch of buildings is a university. Now, ask yourself 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 haul 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 he's 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 of sentience 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. I mean, you have patients that actually suffer pains, and you try to get an objective science of that. Okay, I promised to refute all these guys, and 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 won't demonstrate pain behavior, but I can tell you I'm not having any pains right now. So it's an obvious mistake. Why did they make the mistake? The mistake was — and you can go back and read 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 phenomenon in biology, or, for that matter, the rest of science. Thank you very much. (Applause)

Frequently Occurring Word Combinations

ngrams of length 2

collocation frequency
computer program 4
physical world 3
twin traditions 2
program running 2
spirituality move 2
conscious states 2
conscious machine 2
unified conscious 2
objective science 2

ngrams of length 3

collocation frequency
computer program running 2

Important Words

  1. absolute
  2. accept
  3. accepted
  4. accepts
  5. acetylcholine
  6. actual
  7. add
  8. addition
  9. admits
  10. agent
  11. agents
  12. algorithm
  13. analysis
  14. animal
  15. answer
  16. answered
  17. appalling
  18. applause
  19. arbitrary
  20. arch
  21. argument
  22. arm
  23. art
  24. asleep
  25. aspect
  26. assumption
  27. assumptions
  28. attraction
  29. automatically
  30. awareness
  31. awful
  32. axon
  33. bad
  34. basic
  35. beer
  36. begins
  37. behavior
  38. behaviorism
  39. belongs
  40. binary
  41. biological
  42. biology
  43. bit
  44. bottom
  45. brain
  46. brains
  47. briefly
  48. build
  49. buildings
  50. bunch
  51. busy
  52. calculation
  53. calculator
  54. care
  55. carry
  56. carrying
  57. case
  58. causally
  59. caused
  60. cern
  61. channels
  62. character
  63. circuit
  64. claims
  65. cleverly
  66. cocktail
  67. code
  68. coma
  69. combination
  70. common
  71. completely
  72. computation
  73. computational
  74. computations
  75. computer
  76. computers
  77. concerned
  78. condition
  79. conferences
  80. confusion
  81. conscious
  82. consciously
  83. consciousness
  84. consisting
  85. consists
  86. constructed
  87. content
  88. convinced
  89. cortex
  90. couple
  91. create
  92. creates
  93. creations
  94. culture
  95. curious
  96. curiously
  97. damn
  98. damned
  99. day
  100. days
  101. decide
  102. decision
  103. deeper
  104. define
  105. defined
  106. defining
  107. definition
  108. demonstrate
  109. demonstration
  110. depending
  111. derives
  112. descartes
  113. description
  114. detailed
  115. die
  116. difference
  117. digestion
  118. digital
  119. disappointment
  120. discipline
  121. discussing
  122. distinction
  123. domain
  124. doubt
  125. dreamless
  126. dreams
  127. drink
  128. early
  129. easy
  130. electronic
  131. embarrassing
  132. embarrassments
  133. engaging
  134. enormous
  135. evaporate
  136. event
  137. exact
  138. exasperation
  139. exception
  140. exist
  141. existence
  142. exists
  143. experienced
  144. experiences
  145. experts
  146. extra
  147. fact
  148. fall
  149. famous
  150. feature
  151. features
  152. feel
  153. feeling
  154. feels
  155. fibers
  156. field
  157. fields
  158. figure
  159. firings
  160. floor
  161. fool
  162. force
  163. forget
  164. form
  165. french
  166. front
  167. full
  168. function
  169. functions
  170. gave
  171. generates
  172. geneva
  173. genuine
  174. give
  175. giving
  176. god
  177. good
  178. government
  179. gravitational
  180. great
  181. guy
  182. guys
  183. hand
  184. happen
  185. happening
  186. hard
  187. harder
  188. hardware
  189. haul
  190. hope
  191. hostility
  192. human
  193. identical
  194. illusion
  195. illusions
  196. immortality
  197. impatience
  198. implicit
  199. important
  200. income
  201. incredible
  202. influence
  203. influential
  204. intellectual
  205. interested
  206. interpretation
  207. interpreted
  208. intrinsic
  209. ion
  210. irreducible
  211. issues
  212. jar
  213. juice
  214. key
  215. kind
  216. laughter
  217. leave
  218. lecture
  219. left
  220. level
  221. line
  222. liquid
  223. liquidity
  224. listen
  225. literature
  226. lives
  227. logical
  228. long
  229. lot
  230. machine
  231. machinery
  232. manipulation
  233. marriage
  234. marvelous
  235. mass
  236. material
  237. matter
  238. mental
  239. message
  240. mind
  241. mistake
  242. mistakes
  243. mitosis
  244. mode
  245. molecules
  246. moment
  247. money
  248. morning
  249. motor
  250. mountains
  251. move
  252. music
  253. mysterious
  254. nature
  255. neglected
  256. nerve
  257. neurobiological
  258. neurobiologist
  259. neurobiologists
  260. neurologists
  261. neuron
  262. neurons
  263. notice
  264. number
  265. objection
  266. objections
  267. objective
  268. objectively
  269. objectivity
  270. objects
  271. obsolete
  272. obvious
  273. occur
  274. opposed
  275. opposing
  276. outrageous
  277. pain
  278. pains
  279. paper
  280. paralyzing
  281. part
  282. parties
  283. patients
  284. people
  285. persistent
  286. phenomena
  287. phenomenon
  288. philosophical
  289. philosophy
  290. photosynthesis
  291. physical
  292. piece
  293. pocket
  294. position
  295. power
  296. problem
  297. problems
  298. processes
  299. program
  300. progress
  301. promised
  302. property
  303. pun
  304. purely
  305. qualitative
  306. qualities
  307. questions
  308. rainbows
  309. raise
  310. raising
  311. read
  312. ready
  313. real
  314. reality
  315. realized
  316. reason
  317. refute
  318. refuted
  319. relative
  320. religious
  321. reluctance
  322. research
  323. rest
  324. rich
  325. rid
  326. robot
  327. robotics
  328. running
  329. science
  330. scientific
  331. scientists
  332. searle
  333. secreted
  334. secreting
  335. semantics
  336. sense
  337. sentience
  338. sequence
  339. set
  340. setting
  341. share
  342. shoes
  343. showed
  344. showing
  345. shown
  346. sight
  347. simple
  348. simply
  349. single
  350. sky
  351. sleep
  352. slow
  353. solid
  354. solution
  355. sorts
  356. soul
  357. sound
  358. source
  359. spent
  360. spiritual
  361. spirituality
  362. squirted
  363. stabbers
  364. stable
  365. standard
  366. state
  367. states
  368. step
  369. stomachache
  370. straightforward
  371. stretches
  372. struck
  373. study
  374. subject
  375. subjective
  376. subjectivity
  377. suffer
  378. summer
  379. sun
  380. sunsets
  381. symbol
  382. symbolic
  383. symbols
  384. syntactical
  385. syntax
  386. system
  387. talk
  388. talked
  389. talking
  390. target
  391. tax
  392. tells
  393. tend
  394. tenure
  395. terminate
  396. terminology
  397. thinks
  398. thought
  399. time
  400. told
  401. totally
  402. tradition
  403. traditional
  404. traditions
  405. trait
  406. trouble
  407. true
  408. twin
  409. ucsf
  410. unconscious
  411. understanding
  412. unified
  413. university
  414. vacations
  415. vocabularies
  416. voice
  417. wake
  418. watch
  419. water
  420. weather
  421. weight
  422. wonderful
  423. working
  424. works
  425. world
  426. worry
  427. worst
  428. wrong
  429. yeah
  430. years
  431. zeros
  432. zombie