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Right now
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you have a movie playing inside your head.
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It's an amazing multi-track movie.
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It has 3D vision and surround sound
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for what you're seeing and hearing right now,
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but that's just the start of it.
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Your movie has smell and taste and touch.
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It has a sense of your body,
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pain, hunger, orgasms.
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It has emotions,
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anger and happiness.
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It has memories, like scenes from your childhood
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playing before you.
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And it has this constant voiceover narrative
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in your stream of conscious thinking.
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At the heart of this movie is you
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experiencing all this directly.
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This movie is your stream of consciousness,
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the subject of experience
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of the mind and the world.
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Consciousness is one of the fundamental facts
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of human existence.
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Each of us is conscious.
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We all have our own inner movie,
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you and you and you.
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There's nothing we know about more directly.
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At least, I know about my consciousness directly.
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I can't be certain that you guys are conscious.
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Consciousness also is what makes life worth living.
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If we weren't conscious, nothing in our lives
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would have meaning or value.
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But at the same time, it's the most
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mysterious phenomenon in the universe.
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Why are we conscious?
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Why do we have these inner movies?
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Why aren't we just robots
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who process all this input,
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produce all that output,
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without experiencing the inner movie at all?
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Right now, nobody knows the answers
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to those questions.
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I'm going to suggest that to integrate consciousness
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into science, some radical ideas may be needed.
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Some people say a science of consciousness
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is impossible.
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Science, by its nature, is objective.
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Consciousness, by its nature, is subjective.
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So there can never be a science of consciousness.
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For much of the 20th century, that view held sway.
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Psychologists studied behavior objectively,
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neuroscientists studied the brain objectively,
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and nobody even mentioned consciousness.
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Even 30 years ago, when TED got started,
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there was very little scientific work
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on consciousness.
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Now, about 20 years ago,
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all that began to change.
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Neuroscientists like Francis Crick
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and physicists like Roger Penrose
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said now is the time for science
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to attack consciousness.
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And since then, there's been a real explosion,
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a flowering of scientific work
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on consciousness.
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And this work has been wonderful. It's been great.
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But it also has some fundamental
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limitations so far.
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The centerpiece
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of the science of consciousness in recent years
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has been the search for correlations,
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correlations between certain areas of the brain
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and certain states of consciousness.
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We saw some of this kind of work
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from Nancy Kanwisher and the wonderful work
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she presented just a few minutes ago.
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Now we understand much better, for example,
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the kinds of brain areas that go along with
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the conscious experience of seeing faces
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or of feeling pain
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or of feeling happy.
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But this is still a science of correlations.
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It's not a science of explanations.
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We know that these brain areas
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go along with certain kinds of conscious experience,
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but we don't know why they do.
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I like to put this by saying
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that this kind of work from neuroscience
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is answering some of the questions
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we want answered about consciousness,
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the questions about what certain brain areas do
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and what they correlate with.
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But in a certain sense, those are the easy problems.
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No knock on the neuroscientists.
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There are no truly easy
problems with consciousness.
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But it doesn't address the real mystery
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at the core of this subject:
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why is it that all that physical processing in a brain
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should be accompanied by consciousness at all?
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Why is there this inner subjective movie?
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Right now, we don't really have a bead on that.
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And you might say,
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let's just give neuroscience a few years.
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It'll turn out to be another emergent phenomenon
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like traffic jams, like hurricanes,
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like life, and we'll figure it out.
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The classical cases of emergence
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are all cases of emergent behavior,
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how a traffic jam behaves,
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how a hurricane functions,
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how a living organism reproduces
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and adapts and metabolizes,
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all questions about objective functioning.
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You could apply that to the human brain
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in explaining some of the behaviors
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and the functions of the human brain
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as emergent phenomena:
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how we walk, how we talk, how we play chess,
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all these questions about behavior.
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But when it comes to consciousness,
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questions about behavior
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are among the easy problems.
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When it comes to the hard problem,
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that's the question of why is it
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that all this behavior
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is accompanied by subjective experience?
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And here, the standard paradigm
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of emergence,
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even the standard paradigms of neuroscience,
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don't really, so far, have that much to say.
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Now, I'm a scientific materialist at heart.
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I want a scientific theory of consciousness
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that works,
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and for a long time, I banged my head
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against the wall
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looking for a theory of consciousness
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in purely physical terms
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that would work.
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But I eventually came to the conclusion
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that that just didn't work for systematic reasons.
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It's a long story,
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but the core idea is just that what you get
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from purely reductionist explanations
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in physical terms, in brain-based terms,
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is stories about the functioning of a system,
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its structure, its dynamics,
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the behavior it produces,
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great for solving the easy problems —
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how we behave, how we function —
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but when it comes to subjective experience —
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why does all this feel like
something from the inside? —
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that's something fundamentally new,
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and it's always a further question.
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So I think we're at a kind of impasse here.
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We've got this wonderful, great chain of explanation,
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we're used to it, where physics explains chemistry,
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chemistry explains biology,
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biology explains parts of psychology.
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But consciousness
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doesn't seem to fit into this picture.
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On the one hand, it's a datum
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that we're conscious.
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On the other hand, we don't know how
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to accommodate it into our
scientific view of the world.
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So I think consciousness right now
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is a kind of anomaly,
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one that we need to integrate
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into our view of the world, but we don't yet see how.
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Faced with an anomaly like this,
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radical ideas may be needed,
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and I think that we may need one or two ideas
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that initially seem crazy
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before we can come to grips with consciousness
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scientifically.
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Now, there are a few candidates
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for what those crazy ideas might be.
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My friend Dan Dennett, who's here today, has one.
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His crazy idea is that there is no hard problem
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of consciousness.
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The whole idea of the inner subjective movie
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involves a kind of illusion or confusion.
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Actually, all we've got to do is explain
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the objective functions, the behaviors of the brain,
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and then we've explained everything
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that needs to be explained.
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Well I say, more power to him.
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That's the kind of radical idea
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that we need to explore
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if you want to have a purely reductionist
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brain-based theory of consciousness.
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At the same time, for me and for many other people,
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that view is a bit too close to simply
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denying the datum of consciousness
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to be satisfactory.
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So I go in a different direction.
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In the time remaining,
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I want to explore two crazy ideas
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that I think may have some promise.
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The first crazy idea
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is that consciousness is fundamental.
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Physicists sometimes take
some aspects of the universe
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as fundamental building blocks:
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space and time and mass.
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They postulate fundamental laws governing them,
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like the laws of gravity or of quantum mechanics.
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These fundamental properties and laws
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aren't explained in terms of anything more basic.
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Rather, they're taken as primitive,
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and you build up the world from there.
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Now sometimes, the list of fundamentals expands.
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In the 19th century, Maxwell figured out
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that you can't explain electromagnetic phenomena
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in terms of the existing fundamentals —
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space, time, mass, Newton's laws —
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so he postulated fundamental laws
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of electromagnetism
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and postulated electric charge
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as a fundamental element
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that those laws govern.
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I think that's the situation we're in
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with consciousness.
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If you can't explain consciousness
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in terms of the existing fundamentals —
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space, time, mass, charge —
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then as a matter of logic,
you need to expand the list.
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The natural thing to do is to postulate
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consciousness itself as something fundamental,
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a fundamental building block of nature.
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This doesn't mean you suddenly
can't do science with it.
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This opens up the way for you to do science with it.
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What we then need is to study
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the fundamental laws governing consciousness,
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the laws that connect consciousness
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to other fundamentals: space, time, mass,
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physical processes.
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Physicists sometimes say
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that we want fundamental laws so simple
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that we could write them on the front of a t-shirt.
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Well I think something like that is the situation
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we're in with consciousness.
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We want to find fundamental laws so simple
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we could write them on the front of a t-shirt.
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We don't know what those laws are yet,
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but that's what we're after.
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The second crazy idea
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is that consciousness might be universal.
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Every system might have some degree
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of consciousness.
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This view is sometimes called panpsychism:
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pan for all, psych for mind,
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every system is conscious,
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not just humans, dogs, mice, flies,
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but even Rob Knight's microbes,
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elementary particles.
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Even a photon has some degree of consciousness.
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The idea is not that photons are intelligent
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or thinking.
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It's not that a photon
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is wracked with angst
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because it's thinking, "Aww, I'm always
buzzing around near the speed of light.
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I never get to slow down and smell the roses."
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No, not like that.
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But the thought is maybe photons might have
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some element of raw, subjective feeling,
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some primitive precursor to consciousness.
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This may sound a bit kooky to you.
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I mean, why would anyone think such a crazy thing?
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Some motivation comes from the first crazy idea,
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that consciousness is fundamental.
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If it's fundamental, like space and time and mass,
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it's natural to suppose that it might be universal too,
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the way they are.
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It's also worth noting that although the idea
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seems counterintuitive to us,
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it's much less counterintuitive to people
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from different cultures,
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where the human mind is seen as much more
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continuous with nature.
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A deeper motivation comes from the idea that
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perhaps the most simple and powerful way
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to find fundamental laws connecting consciousness
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to physical processing
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is to link consciousness to information.
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Wherever there's information processing,
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there's consciousness.
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Complex information processing, like in a human,
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complex consciousness.
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Simple information processing,
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simple consciousness.
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A really exciting thing is in recent years
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a neuroscientist, Giulio Tononi,
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has taken this kind of theory
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and developed it rigorously
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with a mathematical theory.
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He has a mathematical measure
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of information integration
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which he calls phi,
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measuring the amount of information
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integrated in a system.
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And he supposes that phi goes along
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with consciousness.
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So in a human brain,
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incredibly large amount of information integration,
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high degree of phi,
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a whole lot of consciousness.
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In a mouse, medium degree
of information integration,
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still pretty significant,
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pretty serious amount of consciousness.
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But as you go down to worms,
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microbes, particles,
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the amount of phi falls off.
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The amount of information integration falls off,
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but it's still non-zero.
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On Tononi's theory,
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there's still going to be a non-zero degree
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of consciousness.
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In effect, he's proposing a fundamental law
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of consciousness: high phi, high consciousness.
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Now, I don't know if this theory is right,
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but it's actually perhaps the leading theory right now
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in the science of consciousness,
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and it's been used to integrate a whole range
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of scientific data,
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and it does have a nice property
that it is in fact simple enough
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you can write it on the front of a t-shirt.
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Another final motivation is that
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panpsychism might help us to integrate
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consciousness into the physical world.
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Physicists and philosophers have often observed
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that physics is curiously abstract.
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It describes the structure of reality
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using a bunch of equations,
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but it doesn't tell us about the reality
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that underlies it.
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As Stephen Hawking puts it,
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what puts the fire into the equations?
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Well, on the panpsychist view,
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you can leave the equations of physics as they are,
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but you can take them to be describing
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the flux of consciousness.
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That's what physics really is ultimately doing,
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describing the flux of consciousness.
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On this view, it's consciousness
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that puts the fire into the equations.
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On that view, consciousness doesn't dangle
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outside the physical world
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as some kind of extra.
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It's there right at its heart.
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This view, I think, the panpsychist view,
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has the potential to transfigure our relationship
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to nature,
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and it may have some pretty serious social
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and ethical consequences.
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Some of these may be counterintuitive.
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I used to think I shouldn't eat anything
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which is conscious,
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so therefore I should be vegetarian.
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Now, if you're a panpsychist and you take that view,
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you're going to go very hungry.
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So I think when you think about it,
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this tends to transfigure your views,
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whereas what matters for ethical purposes
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and moral considerations,
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not so much the fact of consciousness,
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but the degree and the complexity of consciousness.
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It's also natural to ask about consciousness
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in other systems, like computers.
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What about the artificially intelligent system
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in the movie "Her," Samantha?
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Is she conscious?
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Well, if you take the informational,
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panpsychist view,
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she certainly has complicated information processing
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and integration,
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so the answer is very likely yes, she is conscious.
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If that's right, it raises pretty serious
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ethical issues about both the ethics
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of developing intelligent computer systems
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and the ethics of turning them off.
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Finally, you might ask about the consciousness
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of whole groups,
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the planet.
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Does Canada have its own consciousness?
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Or at a more local level,
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does an integrated group
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like the audience at a TED conference,
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are we right now having a
collective TED consciousness,
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an inner movie
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for this collective TED group
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which is distinct from the inner movies
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of each of our parts?
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I don't know the answer to that question,
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but I think it's at least one
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worth taking seriously.
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Okay, so this panpsychist vision,
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it is a radical one,
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and I don't know that it's correct.
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I'm actually more confident about
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the first crazy idea,
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that consciousness is fundamental,
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than about the second one,
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that it's universal.
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I mean, the view raises any number of questions,
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has any number of challenges,
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like how do those little bits
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of consciousness add up
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to the kind of complex consciousness
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we know and love.
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If we can answer those questions,
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then I think we're going to be well on our way
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to a serious theory of consciousness.
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If not, well, this is the hardest problem perhaps
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in science and philosophy.
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We can't expect to solve it overnight.
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But I do think we're going to figure it out eventually.
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Understanding consciousness is a real key, I think,
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both to understanding the universe
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and to understanding ourselves.
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It may just take the right crazy idea.
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Thank you.
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(Applause)