Transcript for David Chalmers uncut


Steve Paulson:  You are widely regarded as one of the leading philosophers of the mind. Why do you keep coming back to questions about consciousness, a subject you've now been studying for decades?

David Chalmers:  Well, for me consciousness poses just about the most interesting unsolved problems in the world. I mean I came at this from a background in science and mathematics and there's a sense that okay, although physics and mathematics is still exciting today there was a sense they were more exciting a few hundred years ago when everything was unknown. And it just struck me that the problem right now that stands out as being unknown, unsolved in the way that problems say in the foundations of physics were a few hundred years ago, problems of the mind and in particular the problem of consciousness. How is it that physical processes in a brain give you conscious experience? It's just always fascinated me.

Paulson:  So, you're saying the science of the mind is perhaps the last great unanswered question in science? Maybe in philosophy too?

Chalmers:  Maybe the last great...I mean there's lots of small unanswered questions and even pretty big ones but if you want to go for a place where we really don't have a clue or where there's still just a really enormous mystery at the very heart of the issue, I think it's in the problems of the mind and in particular it's an ancient philosophical problem, the mind/body problem, what's the relationship between mind and body. In its contemporary guise it's really turned into the consciousness brain problem. What's the relationship between the brain and consciousness and we're still just coming to grips with that one.

Paulson:  Now, if you talk to brain scientists, most will say it's just a matter of time before science unlocks the mysteries of the mind and they usually say neuroscience is the path to do this. I mean this is the discipline that will crack the puzzle of consciousness. What do you think?

Chalmers:  Well, I think it's reasonable to think that brain science and neuroscience is going to be a huge component of whatever the ultimate solution is but I think it's also, if you talk to some of those brain scientists, maybe late at night off the record, I think you'll find that there's about as big of diversity of opinion among brain scientists about the problem of consciousness as there is among philosophers. That is almost everyone will recognize that at least right now we're not even close to a solution. And maybe the division is between those who think that, 'well, if we just eventually keep doing it we'll come across something and that will be the key to the solution.' And people who think, 'Well, no we need to be doing something fundamentally different from what we're doing now to get to consciousness.'

I mean the basic worry is that if we're dealing with questions of explaining say behavior, from the third person point of view then it looks like the brain approach is pretty good - treat the mind as a giant computer and see what it gives rise to. But if we're interested in the problems of consciousness from the first person point of view there's just this basic mystery - why does all this processing in the brain give you a first person point of view. I think every now and then an ambitious neuroscientist writes a book claiming to solve the problem but I don't think even most neuroscientists have been too convinced by that so far.

Paulson:  Now, is the big question whether there are certain aspects of consciousness that have no neuro-correlates in the brain?

Chalmers:  Not exactly. I mean it's really taken for granted by most people in this area including me that there will be very strong correlations between the brain and consciousness. So a certain area of your brain lights up, you get some consciousness that goes along with it. What we're looking for though is something more than correlation. I think what we're looking for is explanation, some kind of explanation of how it is that when you put all these bits together in the brain and set up such a complicated circuit and so on why does that give you consciousness? And if we just leave it at the level of correlation, yeah, well this brain process lights up consciousness lights up. That falls very far short of an explanation. It doesn't tell us, for example, whether consciousness just is the brain process or whether consciousness is something completely separate which is correlated with the brain process.

Paulson:  Now you are best known for making the distinction between what you have called the hard and easy problems of consciousness. Can you explain the difference?

Chalmers:  Yeah. So this goes back to a conference, maybe the first really big international conference on consciousness about 16 years ago in Tuscon, Arizona, which I went along to and I thought just for the first few minutes of the...I gave a talk there. For the first few minutes I thought I'll just set up what the problems are because different people when they talk about consciousness at these events, the word consciousness is so ambiguous, it means so many different things to different people, so let's just separate out a few of the problems. The easy problems, as I called them then, were problems roughly speaking tied to objective behavior and to the mechanisms that produce them. So the difference between say being awake and responsive versus being asleep and unresponsive. That's something you can characterize from the third person point of view and maybe there will be a neural brain based solution to that or the problem of how it is that you respond to a given stimulus that you see. And maybe the brain integrates information about it, you produce a verbal report, that's also one of the "easy problems" in the sense that although there's a whole lot about that we don't understand, there's no great mystery about seeing how it is that a brain process could bring about that behavior.

The hard problem has always been the problem of how is it that all this processing in the brain gives rise to first person subjective experience, the feeling of seeing, of hearing, this inner movie that we have in our mind when we perceive, when we think, when we feel, when we remember. I mean there's something it’s like to be us as human beings and the hard problem is basically why does all this processing in the brain give us this bizarre, first person, something it’s like from the inside.

Paulson:  I've always wondered about where our thoughts come from, not that we have the ability to think that seemingly random thoughts pop into our heads. Is this a hard problem or an easy problem?

Chalmers:  It's got elements of both insofar as the thoughts have a conscious aspect. It feels like something to think from the first person point of view but if you're dealing with the question of where did a particular thought come from, why did today you think about some event that happened in your childhood and why tomorrow you're going to think about your mother. I guess I'd put that on the side of the easy problems in the sense that we can imagine there's eventually going to be a brain based or computer based solution to this in terms of hey there are certain memories in your brain and there's certain associations and something triggers the thought about your mother or maybe it's just random and there's random selection of all the memory information you have. So I guess I'd...that's a really interesting and difficult problem but it's not officially on the side of the hard problem of consciousness.

Paulson:  It's interesting because it also gets to the question of what we would associate with creativity. For instance, the novelist who is creating a story and characters out of her imagination or a jazz musician who riffs on a tune to make it his own. Are you saying these are easy problems ultimately?

Chalmers:  Well, I'd say that creativity and creative processes do involve a really distinct and interesting conscious experience. The experience that the jazz musician is getting into while they're being musically creative. At the same time though I think there are complex and simple forms of consciousness and in a way the core of the hard problem of consciousness is posed just as strongly by far simpler states than creativity and complex thought. You can pose the hard problem of consciousness just by thinking about something as simple as feeling a pain. I pinched myself and ow, okay that hurt a bit. Now I can tell a story about how it is that sent a signal up my nerves to the brain, stimulated pain areas of the brain, but why did this have that distinctive first person experience of hurting. There's nothing especially creative or complex about that but it still poses the hard problem.

Of course, the forms of consciousness that come up in creativity or complex thought are all the more strange and mysterious. But I think the core problem even arises from the simple cases.

Paulson:  So why is this hard problem of consciousness so hard? I mean why is it so hard for science, for neuroscience, for cognitive science to explain this subjective experience, this first person experience?

Chalmers:  Well, one way to think about it is that science is set up from the start to be objective and we're only comfortable with things in science when they're full objective. We have objective mechanisms, measurable from the third person point of view, we gather our data inter-subjectively, every scientist can access the phenomena the same, we can all make the same measurements, and that's how science is meant to be. But consciousness...and that works so well in physics, biology, even some areas of the science of the mind. But consciousness by it's nature is subjective. It's all about subjective experience from the first person point of view. It's not something you can directly measure from the outside. I mean I don't even know for sure but I'm talking to you that you're conscious. I believe you are. I take what you say as some kind of evidence for it but I can't measure it directly. We can only get at it indirectly. And the kinds of mechanistic explanation we get to in science in terms of explaining what it is that systems do just don't seem to work so well for this essentially subjective phenomenon. So I think about this - science is basically all about gathering what we might call third person data traditionally, data equally accessible to everyone. Consciousness really involves what we might think of as first person data.

Paulson:  Basically if you want to know about my mind I have to tell you about it?

Chalmers:  Roughly. Yeah, that's basically right. You know for sure about your consciousness. I know for sure about my own consciousness. And then we can communicate it to each other by telling each other in verbal report is in fact a method which is used the most in the science of consciousness. But it still makes people uncomfortable because we're only getting at the phenomenon fairly indirectly and to explain things like the verbal report isn't to actually explain the state of consciousness itself. I mean it's one thing to explain why you say ow. It's another thing to explain that feeling of pain that underlies your saying ow.

Paulson:  Now are these questions about consciousness also related to questions about what the self is, what it means to be me for instance?

Chalmers:  I'd say they're very closely connected. I mean any self that we think of or any system that we think of as deserving the name self or person would have to be a conscious system. I think if it wasn't a first person perspective it didn't feel like something to be a system. That system couldn't have a self. Maybe in the simple forms of consciousness which are...I think maybe flies have a simple form of consciousness. I don't know whether you want to say they have a self. One thing we might say is they're certainly not conscious of themselves.

So one thing that we have as human beings is we have ourself. We have consciousness. We also have this consciousness of ourselves as selves and that maybe something that makes humans, human consciousness, distinctive. But on the other hand consciousness itself and maybe even self itself, maybe flies could be said to have a primitive sort of self and a primitive sort of consciousness. They're just not conscious of themselves.

Paulson:  Are you talking about the limits of materialism? I mean the idea that the mental is nothing more than brain mechanics. Is that part of your critique here?

Chalmers:  It is, yes. One of the big issues in the philosophy of the mind is is the mind just the brain. I mean is a physical process is enough to explain what's in your mind and what's in your consciousness and I've been somewhat reluctantly led to the conclusion by the sorts of considerations we've been talking about that in fact materialism doesn't have the resources to fully explain consciousness. So to fully explain consciousness you have to expand your furniture, your basic furniture of science, from beyond the resources just say physics. I mean the materialist view says basically there's a few fundamental properties in the world - space and time and mass and charge and a few laws that connect them - and everything can ultimately be explained in terms of that physics and chemistry.

Paulson:  Everything in chemistry, biology, ultimately can be reduced to the properties of physics.

Chalmers:  Right. So you've got this great chain of being in a way from physics upward. But my own view is that although this works so well in chemistry and biology and so on for the reasons we've been talking about when it comes to consciousness this reductionist program doesn't succeed and at this point we should just rather than saying...we could just say it's a giant mystery but I think at this point what we should say is what you do in science is...Occam’s Razor don't multiply entities without necessity. But in this case there is necessity. I think it's basically what's happening here is something is telling us we need more primitives in our ontology so to speak. It's not just space, time, mass, and charge.

So my own view is we should take something like consciousness as a primitive element of the world, a fundamental property if you like, in the way that physics takes space and time and mass and charge.

Paulson:  That's fascinating. I mean you're suggesting that consciousness may have its own fundamental property of nature so to speak?

Chalmers:  Basically, yes. Yeah, I mean consciousness, or maybe some other weird property, some other weird new properties, proto-consciousness which could somehow produce consciousness. But we do need to expand the ontology of fundamental properties. That's my view. Physics is made to be a theory of everything, fundamental properties that explain everything. But if it turns out it doesn't explain everything then I think what we have to do as scientists is to expand our primitives.

Paulson: So what would that fundamental property of consciousness be?

Chalmers:  Well, at this point we really don't know. So we're really in the realm of speculation and I get to do the speculation because I'm a philosopher but I can't say where...We're not remotely close yet to the point where we have the details of theory. I mean I'll be happy if we have it in 50 years. It could be 200 years but one thought is just some certain basic aspects of consciousness, some primitive dimensions of consciousness. I mean analogies maybe are, where if you have color it seems like this big complex experience but we can break down color into a few primitive dimensions - hue, saturation, brightness - from which you can get all the properties of color that we seem to experience.

Or maybe it will turn out there are four or five primitive dimensions of consciousness so that we can break down the complex multifaceted multisensory consciousness that we have and see how that could be the property of the result of four or five basic properties of consciousness put together in the right configurations. I mean at the moment this is just speculation but you might...what we basically...just as in physics you've got fundamental laws that connect these fundamental properties to each other, for a fundamental theory of consciousness of my view what you need is the theory that connects these fundamental physical properties like space, time, charge, and so on to consciousness, roughly telling you when you've got a physical system of these properties you'll get a conscious system. With these properties and this is what consciousness will be like. We don't have that theory yet but if we did maybe that would be a theory of consciousness.

Paulson:  I want to push you to speculate a little bit more. You have suggested that maybe information is this fundamental property that's somehow connected to consciousness. And I know there are some scientists out there including some physicists who say that maybe information is maybe the most primary, most fundamental property of all. How far are you willing to run with that?

Chalmers:  Yeah, so in a book I wrote in '96, The Conscious Mind, I speculated a fair amount about information maybe being the key concept and that basically you've got information embodied physically and physics can somehow be seen as a giant informational processing of bits affecting other bits and so on. And then we add the other fundamental postulate that wherever you find information that information basically has two aspects. The other aspect is a conscious aspect. So physical information will correlate then with experience to conscious information and that would kind of have the status of a fundamental law in the system.

So what we do find in our conscious visual experience is it's kind of like's a computer monitor all right. You've got a big pixels, color pixels spread out in space over a visual field. You can see all of that as a giant information structure. Somehow it's a projection of the information structure in your brain. So my thought then was maybe we could use this to build a theory around. I've got to say that I haven't gotten a whole lot further with those ideas about information than I was about 14 years ago and I'm inclined to think maybe it's a bit early to be really building the details of a theory around that. But that's the kind of speculation that points at least towards some interesting ideas for how a theory might eventually go.

Paulson:  I mean let's just play with this for a moment. Wouldn't information have to be made of something or consist of something? You can't just talk about information itself can you?

Chalmers:  That's a really good question. It is certainly if you look at your average computer or phone line or place where information is, it's always realized by something - voltage circuits in a computer or electricity. Some people have suggested that maybe there's a fundamental level of information that isn't realized by anything more primitive than itself. It's just basic bytes - ones and zeros. Just two states which are different from each other and it's not that there's something else that makes that difference. It's not that, you know, it's like red versus blue or on versus off. It's just two different bytes.

The physicist, John Wheeler, called this idea it from bit. Rather than getting bits of information from some underlying level of it, like voltages, the fact that everything in the world is built on this level of pure information. The idea is a bit crazy and it's not totally clear that it makes sense to think of pure information but I at least find that as sort of an attractive speculation.

If you were to have a level of matter or something underlying your information, I think you can have that here as well and then we'll just say the information is embodied in matter. It's also embodied in consciousness.

Paulson:  Now, I know there are a few renegade scientists who think we need quantum physics to explain consciousness. What do you think?

Chalmers:  There are a lot of intriguing connections between quantum physics and consciousness. I mean my first reaction is well it's not obvious how you get from classical physics to consciousness but it's not at all obvious how bringing in quantum mechanics helps. I mean you've got say Roger Penrose and my art colleague Stewart Hemeroff at Arizona, they think that they key to consciousness is all about the collapse of way functions by quantum gravity mechanisms and microtubules inside the brain. But then there's basic natural questions to arise here is well we didn't know how processing neurons will give you consciousness. It's just there was an explanatory gap if you'd like. Well, it looks like there's exactly the same explanatory gap between a way function collapses in microtubules and consciousness.

At this point though some people are led to think that quantum mechanics might have a special role in a theory because there are versions of quantum mechanics that actually take consciousness as fundamental, as primitive, and give it a role. So there's a version of quantum mechanics that says wave functions collapse every now and then. They go from a very spread out state to a determinate state, Schrödinger’s cat goes from being both alive and dead to being say alive. When does this happen? It happens when someone makes a measurement.

What's a measurement? Well, that's basically where a system impacts on someone's consciousness. So there's a version of quantum mechanics that says basically consciousness is what collapses the way function. This takes consciousness as primitive and gives it a role and since one of the big questions around here is if consciousness is this primitive what's it role in the physical world? Does it make a difference? Quantum mechanics at least I think has some interesting speculative thought about what that role could be.

Paulson:  But it seems like the problems with that is if you take it to its absurd conclusion, nothing would happen if someone doesn't think about it.

Chalmers:  It's an interesting question, yeah. So just say you already got consciousness in complex systems and just say those very complex systems took billions of years to evolve as we currently think they did. On this view what happened to the universe for those first few billion years when nobody was conscious? I guess the universe must have evolved at a big giant super position of every possible state on the way function and then at a certain point on one of these branches of the way function evolution got to the point where the first glimmer of consciousness came in there and got affected and then at that point the whole way function collapsed and evolutionary history became determinate.

So, yeah, it is a pretty weird and wild view. But one thing we've learned from quantum mechanics is there's no way to understand quantum mechanics without it being a weird and wild view.

Paulson:  In some ways your views, for instance, your willingness to entertain this connection between consciousness and quantum physics, it would seem to resonate with people with a spiritual or religious bent because they always say that the mind cannot be reduced simply to neural correlates. Is there a spiritual component to your perspective?

Chalmers:  Not for me personally. I mean I'm not a religious person at all. I guess I'm an atheist. I've got my own average watered down academic humanist’s spirituality if you like but nothing more than that. I do find these views do tend to resonate quite often with people with religious backgrounds whether it's say a Christian background or quite often things like Buddhism and their ideas in Buddhism and other eastern religions that some people find resonating with. Consciousness is primitive. Consciousness is the ground of all being. I guess that's okay with me but I'm just very cautious about drawing too direct a connection.

I've been led to these views just by thinking about these things with relatively objective scientific and philosophical perspectives. Some people think the only reason you might want to have views like this is for broadly religious and spiritual reasons. That's not the case at all.

Paulson:  And I think there's a specific reason for that is those people with these religious views would say that there's something about consciousness that goes beyond the individual person. There's some way that my mind can tap into some larger cosmic mind.

Chalmers:  Yeah, maybe that's what they think. Or maybe they're motivated by thoughts of life after death that they could be if consciousness is something separate from the body then maybe that gives some solace to people who think that our consciousness may go on after our bodies are dead. All I can say is I've got no evidence about life after death. The view that I've put forward doesn't make any particular predictions about that. My own view is probably sad but true and when my body dies my consciousness will either die or dissolve or fragment along with it.

But I guess it's the case that certainly is the case that if people want to find...if you do believe...if you are inclined to believe in say non-physical souls, which I'm not, but if you are inclined to believe in something like a soul, you could take elements of the picture I'm putting forward here and graph the soul onto it. I just want to say that's not compulsory. That's going way, way beyond where the science or the philosophy takes you. So I guess although I've got some fairly radical views in some sense I want to be conservative about it and say well this is where the arguments and the evidence take you. Anything beyond that is really speculation.

Paulson:  It sounds like you are describing an impasse here, perhaps an insoluble problem for people who study the mind. I mean this whole business of subjective experience of where it comes from. Is there a future to figuring this out?

Chalmers:  Well, the funny thing is despite everything we've been saying, the science of consciousness has just gone from strength to strength over the last 15, 20 years. When I was a graduate student around 1990, almost nobody was working on consciousness in neuroscience and psychology. Even in philosophy it was a bit of a fringe topic.

Paulson:  Which is fascinating because I mean in some ways you think this is the greatest mystery there is and yet up until fairly recently no one was actually studying it.

Chalmers:  I think people didn't really know how to deal with it. It was just was like the crazy aunt in the attic as someone put it. Well, how do we deal with it? So one thing that changed is that in the 1990s people started figuring out some relatively rigorous ways to study the neural correlates of consciousness. So neuroscientists became interested in consciousness. Even without solving the hard problem, giving a theory of consciousness they could do experiments that taught us this bit of the brain is correlating with your visual experience of consciousness. This one is not. And that's really gotten us places.

Likewise, other things have happened in psychology and in neurology and so it's the science is really getting places. I think it's fair to say okay no one's yet solved the hard problem so I suppose you could say that's remaining an impasse. And I do think like most of the great problems of philosophy, the great problems of philosophy never get completely solved for once and for all. There's probably going to remain arguments about these things even in hundreds of years.

Still, I'm inclined to be an optimist and my own view is there are...we're not that close yet to exploring the space of possible theories and once we've got a whole lot more evidence from brain sciences and a whole lot more philosophical thought and a whole more theory development, then there's room for a whole space of theories that we haven't gotten to yet.

Paulson:  What would that take? I mean how do you get to this next level of somehow cracking the nut of subjective experience?

Chalmers:  Here's my view for what we need to do. It's basically first of all we gather data. We gather third person data about the brain and behavior. That's your average thing from neuroscience. But we also need to get very good at gathering first person data, basically measuring our own conscious experiences from the inside, you know, introspect them, catalog their properties, develop language for representing and systematizing our conscious experiences and then deal with science which consists of sort of roughly speaking bringing the third person data and the first person data together so you can form a hypothesis. When you have this third person state you then get this state of consciousness. I mean this is already happening now in a very basic way with the study of neural correlates of consciousness. But we just need something much more general, powerful, and systematic.

We're not there yet but eventually you can imagine we'll be led to boil down that connection to some really simple and powerful underlying connections between physical process and consciousness. When you have this kind of information physically, you get this kind of conscious state, and ultimately be led to your fundamental laws of consciousness, still taking consciousness as a primitive but connecting it to the other primitives. And for me that would be a theory.

Paulson:  Yeah, but I can see for instance that if you do a lot of MRI studies, I mean functional MRI studies, and have people then report what they've been thinking and match that with brain waves, certainly you can construct a fairly exact science of correlation I would think but can you ever get to the causal mechanism of what actually generates those experiences? I mean is that...can you imagine a way that that could ever happen?

Chalmers:  Well, in my view this parallels an issue which comes up in thinking about physics. Wherever you have a fundamental law in physics, something is kind of taken for granted. So Newton came up with these laws of gravitation and so on and they said okay well you've got this thing here, this action at a distance, things with certain mass attract each other but how does it happen? What's the mechanism? Well, some things just get taken as primitive and in Newton's theory that was the law of gravitation. So that's just how it is with fundamental laws and science.

Now, we're not used to doing that outside of physics. But if I'm right that in this case of consciousness we have to do something a bit like that here too. This is going to be...there are going to be primitives in the physics and primitives in the consciousness and we'll have a fundamental law that connects them, whatever that is, and then that will just have to be taken as a primitive in our theory in the way that the law of gravity is. And they're looking for a mechanism for how does that...why is that could ask why is that a law of nature and that's at the point where we kind of throw up our hands and science just doesn't have very much to say about why we live in a universe with the laws of nature that we have. We just say that's primitive. I mean maybe someone could explain that but that's really getting into the realm of very deep cosmic speculation.

Paulson:  Do you think the computers of the future, presumably far more advanced than the computers of today, will be conscious?

Chalmers:  Yeah, I don't see why not. I don't see what's special about human biology. I mean it's hard to see how silicon chips will give you consciousness but it's also hard to see how neurons will give you consciousness. I don't see a difference in principle; maybe you could replace the neurons in a brain gradually by silicon chips. A quarter of your brain is replaced, half your brain is replaced, we might eventually upload the whole thing. My own view is there is some reason to think that consciousness might be preserved in this process.

One thing we know is if the computer processes are good enough simulations of neurons we'll at least be left with a system which tells us hey I'm conscious. I'm conscious. Because after all that's what we were doing before if it's a good simulation it will say that later. Now so the only question is whether your consciousness gradually disappeared as you underwent this replacement process. I mean we could never rule that out completely but I'm inclined to think that computers can be conscious.

In fact I've been thinking about this a lot in another context lately. I'm thinking about what happens when computers become more intelligent than human beings whether that be sort of super intelligence and super consciousness that goes far beyond our kind of consciousness.

Paulson:  What do you think? Do you think that will happen?

Chalmers:  I think it's a possibility. You know people talk about the singularity—this moment when computers get artificially designed. We design computer that are smarter than we are then they'll be better than us presumably at designing computers. So they'll be able to design computers which are smarter than the best computers we could design and which are therefore smarter than themselves. So you repeat this process. You get computers designing ever smarter computers and before long you're left with something like super intelligence. I don't see why something like this shouldn't happen. The question then is where do we stand in this process? Maybe we should be uploading and upgrading ourselves throughout the whole process so that the super intelligent beings are not so to speak our masters but our us.

There are different paths to artificial intelligence starting from the brain and uploading and upgrading, creating something new. Maybe it's a slightly happier scenario for humans if we start from the brain.

Paulson:  It does raise the question of what it means for a computer to be smarter. Obviously computer has far higher capacity for information processing but is that what smarter really means? I guess are there some qualities of the human brain that will also elude what computers can do?

Chalmers:  Yeah so it's got to be a lot more than just information processing or memory or speed. Those things are at least relevant to intelligence. If I just do something twice as fast that counts we often count that as being in some sense smarter. Things like creativity have to be in there; insight flexibility all the things which current computers are terrible at. Right now computers have very good memory and processing capacity but not much in the way of insight, not much in the way of creativity, not much in the way of flexibility.

So I don't see why those things have to be in principle obstacles forever. I mean presumably if someone could simulate a whole brain and if the brain is what's actually producing the behavior then that could in principle be built into a computer. Now not soon probably. Maybe not for 100 years but the question is, is there something about human information processing that couldn't be built into a computer. At this point what I say about consciousness I don't yet see any reason to think that at least the process...just here we're just talking about the easy problems. Intelligence understanding in behavioral terms. I don't see any reason to think a computer couldn't have that.

Then of course is the further question if it did have all of this intelligent or super intelligent behavior would it be conscious? And of course that's a further question. You might say we'd be left with super intelligent zombie computers wonderful behavioral capacities no consciousness at all.

But my own view is that there's at least this correlation between information processing in physical systems and information processing consciousness. So that probably if you did have this super intelligent information processing you'd most likely have some kind of bizarre super consciousness that went along with it.

Paulson:  Of course there's also a great philosophical question which is could we just be all living in some simulated computer? Could we be living in the matrix?

Chalmers:  Oh yeah well that's a great question which I've thought a fair amount about. You might think that there's actually some reason to take this seriously. After all simulation technology is getting better and better. People we have got Sim Earth, Sim City, Sim Life, the Sims, pretty soon there's going to be Sim Universe. Everyone is going to be running copies of Sim Universe in the background on their desktop. Eventually these simulations will be really good. They'll be...everyone will be running a simulation with thousands or billions of simulated people.

There will be way more simulated people in the universe than original people. Then you have to sit back and think, well what are the odds that I'm one of the ones at level zero one of the people writing the simulations? The others…with so many more simulated people, the chances are maybe you and I are among them.

Paulson:  I mean you consider this as a serious possibility. I mean this is not just something to laugh away?

Chalmers:  I do actually, yeah. I mean I think we'll probably create the simulated universes. We'll be able to see those people going through conversations just like this one and then it's going to make us sit back and think well is this telling us something about ourselves. I don't know that we're in a simulation but I think this does make it a hypothesis we should at least take seriously - worlds within worlds within worlds - simulated worlds within other simulated world. I guess from the movie we know about the matrix within a matrix.

Then the philosopher’s question is if that's true well what does that mean. Some people think that if it turns out we're in a simulation none of this is real, we're just victims of a grand disillusionment all of this is just fake. my own view is no, if we are in a simulation well that's very interesting but it doesn't turn the world around us into an illusion. It just tells us something about the nature of the world around us. If it turns out we're living in the metaphysics there are still tables and there are still chairs and there are still people. It's just there's an underlying metaphysics which is fundamentally computational or informational. So actually it plays quite well into the ideas we were talking about before of a world of information. If we're in a matrix we're in a world of information but it's still in its way perfectly real.

Paulson: That is a perfect place to end it. Thank you so much.

Chalmers:  Thanks. It's been a pleasure.

Comments for this interview

Buddha's theory of consciousness (Greg Slater, 07/15/2013 - 10:38am)

re: "This agrees very well with neurological data that shows impulses arrive in the "conscious" just a moment before they get to the "action center" (I've forgotten the neurological term), and we conclude that we "thought of it" before doing it..."
But this doesn't escape from hypothesizing the 'we' that deludes 'itself' about the nature of 'its' consciousness. Such an argument is still requires the introduction a 'homunculus' that is the observer of its own consciousness, which then demands that we hypothesize a second order homunculus to explain the consciousness of the homunculous, and cetera... We are trapped in an endless recursion of observers. And the 'hard problem of consciousness' escapes from and recedes ahead of our futile attempts to capture it in a closed theory...

consciousness (falk burger, 11/04/2012 - 5:26pm)

I have a very strong intuition that we're overthinking the problem, because our vanities will not let us contemplate our ordinariness. Amebas sense and respond. What if sensing and responding IS consciousness? Gautama Buddha saw consciousness as the spontaneous, "conditioned arising" of sensation and impulse, and the sense of self as nothing more than after-the-fact rationalization, an illusion. This agrees very well with neurological data that shows impulses arrive in the "conscious" just a moment before they get to the "action center" (I've forgotten the neurological term), and we conclude that we "thought of it" before doing it, which in fact is exactly what happened, though we wouldn't find it very flattering to think the explanation is a routing by-product. I think it entirely appropriate to generalize this mechanism to consciousness itself. I believe Steve Paulson is clinging to the notion of an extra-cranial "soul" and though he is very well-informed, perceptive and intellectually wide-ranging, this preconception is a handicap here. It might be a very instructive discipline to conduct, or reframe, an entire series of interviews without recourse to metaphysics, then do the whole thing again without recourse to physics, or positivism.
Let me just add that ignorance is really the prevailing state of affairs in all the sciences. We don't know what THIS is; we don't know WHERE we are; we don't know what life is, really, and so forth. Our reality construct is a meticulously crafted, detailed raft of knowledge floating in a sea of metaphysics. The mistake we make is, we are vain, and impatient, and can't resist the temptation to dive off the raft and go swimming in the sea of metaphysics. The moment we do that, we are almost irretrievably lost. Few return from that swim. One final note: Steve says, "Atheists are all over the map" on this question. Naturally! Atheism isn't a philosophy, it is merely a label to distinguish a great variety of philosophies from another world that requires belief in deities and such. A variety of philosophies produce a variety of interpretations. Nothing strange in that. Stimulating as usual, thanks.