GUY RAZ, HOST:
So we've been hearing from brain scientists who are asking how a bunch of neurons and synaptic connections in the brain add up to us, to who we are. But it's consciousness, the subjective experience of the mind, that allows us to ask the question in the first place. And where consciousness comes from - that is an entirely separate question.
DAVID CHALMERS: Well, I like to distinguish between the easy problems of consciousness and the hard problem.
RAZ: This is David Chalmers. He's a philosopher who coined this term, the hard problem of consciousness.
CHALMERS: Well, the easy problems are ultimately a matter of explaining behavior - things we do. And I think brain science is great at problems like that. It can isolate a neural circuit and show how it enables you to see a red object, to respondent and say, that's red. But the hard problem of consciousness is subjective experience. Why, when all that happens in this circuit, does it feel like something? How does a bunch of - 86 billion neurons interacting inside the brain, coming together - how does that produce the subjective experience of a mind and of the world?
RAZ: Here's how David Chalmers begins his TED Talk.
(SOUNDBITE OF TED TALK)
CHALMERS: Right now, you have a movie playing inside your head. It has 3-D vision and surround sound for what you're seeing and hearing right now. Your movie has smell and taste and touch. It has a sense of your body, pain, hunger, orgasms. It has emotions, anger and happiness. It has memories, like scenes from your childhood, playing before you. This movie is your stream of consciousness. If we weren't conscious, nothing in our lives would have meaning or value. But at the same time, it's the most mysterious phenomenon in the universe. Why are we conscious?
RAZ: Why is consciousness more than just the sum of the brain's parts?
CHALMERS: Well, the question is, you know, what is the brain? It's this giant complex computer, a bunch of interacting parts with great complexity. What does all that explain? That explains objective mechanism. Consciousness is subjective by its nature. It's a matter of subjective experience. And it seems that we can imagine all of that stuff going on in the brain without consciousness. And the question is, where is the consciousness from there? It's like, if someone could do that, they'd get a Nobel Prize, you know?
CHALMERS: So here's the mapping from this circuit to this state of consciousness. But underneath that is always going be the question, why and how does the brain give you consciousness in the first place?
(SOUNDBITE OF TED TALK)
CHALMERS: Right now, nobody knows the answers to those questions. So we may need one or two ideas that initially seem crazy before we can come to grips with consciousness, scientifically. The first crazy idea is that consciousness is fundamental. Physicists sometimes take some aspects of the universe as fundamental building blocks - space and time and mass - and you build up the world from there. Well, I think that's the situation we're in. If you can't explain consciousness in terms of the existing fundamentals - space, time - the natural thing to do is to postulate consciousness itself as something fundamental - a fundamental building block of nature. The second crazy idea is that consciousness might be universal. This view is sometimes called panpsychism - pan, for all - psych, for mind. Every system is conscious. Not just humans, dogs, mice, flies, but even microbes. Even a photon has some degree of consciousness. The idea is not that photons are intelligent or thinking. You know, it's not that a photon is wracked with angst because it's thinking, oh, I'm always buzzing around near the speed of light. I never get to slow down and smell the roses. No, not like that. But the thought is, maybe photons might have some element of raw subjective feeling, some primitive precursor to consciousness.
RAZ: So this is a pretty big idea - right? - like, that not just flies, but microbes or photons all have consciousness. And I mean we, like, as humans, we want to believe that our consciousness is what makes us special, right - like, different from anything else.
CHALMERS: Well, I would say yes and no. I'd say the fact of consciousness does not make us special. But maybe we've a special type of consciousness 'cause you know, consciousness is not on and off. It comes in all these rich and amazing varieties. There's vision. There's hearing. There's thinking. There's emotion and so on. So our consciousness is far richer, I think, than the consciousness, say, of a mouse or a fly. But if you want to look for what makes us distinct, don't look for just our being conscious, look for the kind of consciousness we have. For example, we're self-conscious. We're conscious of ourselves. That's not something which, probably, an earthworm has.
(SOUNDBITE OF TED TALK)
CHALMERS: It's also natural to ask about consciousness in other systems, like computers. What about the artificially intelligent system in the movie, "Her," Samantha? Is she conscious? Well, if you take the informational panpsychist's view, she certainly has complicated information processing and integration, so the answer is very likely yes, she is conscious. If that's right, it raises pretty serious ethical issues about both the ethics of developing intelligent computer systems and the ethics of turning them off. Finally, you might ask about the consciousness of whole groups. The planet, or at a more local level, there's an integrated group, like the audience at a TED conference. Are we, right now, having a collective consciousness, an inner movie for this TED group, which is distinct from the inner movies of each of our parts? I don't know the answer to that question, but I think it's at least one worth taking seriously.
RAZ: So if consciousness could be collective, I mean, couldn't it mean that it might not live in the brain?
CHALMERS: Yeah, it's a tricky question. I mean, I think you could say that, you know, if consciousness, for example, is a universal - if it attaches to particles - then, you know, when an electron has consciousness, the consciousness is somehow attached to that particle. It's not like it's somewhere else. I sometimes get attracted by the idea that, you know, consciousness is like what the thing is like on the inside.
CHALMERS: Physics studies all this stuff from the outside - their interactions with each other, their relations to each other. But they've got to have an intrinsic nature. It's got to be something, and physics doesn't tell us about that. Maybe that's consciousness, and maybe when we're introspecting our own consciousness, this is actually getting some insight into the intrinsic nature of the matter inside our brains.
RAZ: Is this the biggest mystery of the brain?
CHALMERS: I think it's the biggest mystery in the universe, if you ask me. But it's certainly the biggest mystery of the brain. Where does consciousness come from? Nobody knows. Nobody understands it. You know, I mean, a few hundred years ago, we were there with, like, you know, space and time. What on earth are they? Where do they come from? Now we understand those pretty well. And we're filling in the scientific picture of the world pretty well at some level, but then consciousness just sticks out like a sore thumb. No one's got a good theory of it. It makes you say, you know, is it just the brain, or is there something more?
RAZ: David Chalmers teaches philosophy at New York University. You can hear his entire talk at ted.com.
(SOUNDBITE OF SONG, "MY BRAIN")
MOSE ALLISON: (Singing) My brain is always ticking - my brain. My brain is always ticking - my brain. My brain is always ticking as long as I am alive and kicking. My brain, cool little cluster - that's my brain.
RAZ: Thanks for listening to our show on The Unknown Brain this week. Our production staff at NPR includes Jeff Rogers, Brent Bachman, Megan Cain, Neva Grant and Chris Benderev, with help from Daniel Shuchman (ph). Barton Girdwood is our intern. In the front office, Eric Newsome and Portia Robertson-Migas. Our partners at TED are Chris Anderson, June Cohen, Deron Triff and Janet Lee. I'm Guy Raz, and you've been listening to the TED RADIO HOUR from NPR.
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