David Chalmers is a philosopher and cognitive scientist specializing in philosophy of mind, philosophy of language, and consciousness. He is perhaps best known for formulating the hard problem of consciousness which could be stated as "why does the feeling which accompanies awareness of sensory information exist at all?"

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OUTLINE:
0:00 - Introduction
2:23 - Nature of reality: Are we living in a simulation?
19:19 - Consciousness in virtual reality
27:46 - Music-color synesthesia
31:40 - What is consciousness?
51:25 - Consciousness and the meaning of life
57:33 - Philosophical zombies
1:01:38 - Creating the illusion of consciousness
1:07:03 - Conversation with a clone
1:11:35 - Free will
1:16:35 - Meta-problem of consciousness
1:18:40 - Is reality an illusion?
1:20:53 - Descartes' evil demon
1:23:20 - Does AGI need conscioussness?
1:33:47 - Exciting future
1:35:32 - Immortality

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The following is a conversation with David Chalmers.

He's a philosopher and cognitive scientist specializing in areas of philosophy of mind, philosophy of language, and consciousness.

He's perhaps best known for formulating the hard problem of consciousness, which could be stated as, why does the feeling which accompanies awareness of sensory information exist at all?

Consciousness is almost entirely a mystery.

Many people who worry about AI safety and ethics believe that in some form consciousness can and should be engineered into AI systems of the future.

So while there's much mystery, disagreement, and discoveries yet to be made about consciousness, these conversations, while fundamentally philosophical in nature, may nevertheless be very important for engineers of modern AI systems to engage in.

This is the Artificial Intelligence Podcast.

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And now, here's my conversation with David Chalmers.

Do you think we're living in a simulation?

There's probably gonna be a lot of simulations in the history of the cosmos.

If the simulation is designed well enough, it'll be indistinguishable from a non-simulated reality.

And although we could keep searching for evidence that we're not in a simulation, any of that evidence in principle could be simulated.

But do you think the thought experiment is interesting or useful to calibrate how we think about the nature of reality?

Yeah, I definitely think it's interesting and useful.

In fact, I'm actually writing a book about this right now, all about the simulation idea, using it to shed light on a whole bunch of philosophical questions.

So, you know, the big 1 is how do we know anything about the external world?

Descartes said, you know, maybe you're being fooled by an evil demon who's stimulating your brain into thinking all this stuff is real when in fact it's all made up.

Well, the modern version of that is how do you know you're not in a simulation?

Then the thought is, if you're in a simulation, none of this is real.

So that's teaching you something about knowledge.

How do you know about the external world?

I think there's also really interesting questions about the nature of reality right here.

If we are in a simulation, is all this real?

The standard view would be, no, we don't.

My view is actually that's wrong, and even if we are in a simulation, all of this is real.

New version of reality, different version of reality, still reality.

So what's the difference between quote unquote real world and the world that we perceive?

So we interact with the world by perceiving it.

It only really exists through the window of our perception system and in our mind.

So it's the difference between something that's quote unquote real, that exists perhaps without us being there and the world as you perceive it.

Well, the world as we perceive it is a very simplified and distorted version of what's going on underneath.

We already know that from just thinking about science.

You know, you don't see too many, obviously, quantum mechanical effects in what we perceive, but we still know quantum mechanics is going on under all things.

So I like to think the world we perceive is this very kind of simplified picture of colors and shapes existing in space and so on.

And we know there's a, that's what the philosopher Wilfred Sellers called the manifest image, the world as it seems to us.

We already know underneath all that is a very different scientific image with atoms or quantum wave functions or super strings or whatever the latest thing is.

And that's the ultimate scientific reality.

So I think of the simulation idea as basically another hypothesis about what the ultimate, say quasi-scientific or metaphysical reality is going on underneath the world or the manifest image.

The world of the manifest image is this very simple thing that we interact with that's neutral on the underlying stuff of reality science could help tell us about that.

Maybe philosophy could help tell us about that too.

And if we eventually take the red pill and find out we're in a simulation, my view is that's just another view about what reality is made of.

The philosopher Immanuel Kant said, what is the nature of the thing in itself?

I've got a glass here and it's got all these, it appears to me a certain way, a certain shape, it's liquid, it's clear.

what is the nature of the thing in itself?

You know, I've got a glass here and it's got all these, it appears to me a certain way, a certain shape, it's liquid, it's clear.

Well, I think of the simulation idea, it's a hypothesis about the nature of the thing in itself.

Turns out if we're in a simulation, the thing in itself, nature of this glass, it's okay, it's actually a bunch of data structures running on a computer in the next universe up.

that's what people tend to do when they think about simulation, they think about our modern computers and somehow trivially, crudely just scaled up in some sense.

But do you think the simulation, I mean In order to actually simulate something as complicated as our universe that's made up of molecules and atoms and particles and quarks and maybe even strings, all of that requires something just infinitely many orders of magnitude more of scale and complexity.

Do you think we're even able to even conceptualize what it would take to simulate our universe?

Or does it just slip into this idea that you basically have to build a universe, something so big to simulate it?

Does it get into this fuzzy area that's not useful at all?

Yeah, I mean, our universe is obviously incredibly complicated.

And for us within our universe to build a simulation of a universe as complicated as ours is gonna have obvious problems here.

If the universe is finite, there's just no way that's gonna work.

Maybe there's some cute way to make it work if the universe is infinite.

Maybe an infinite universe could somehow simulate a copy of itself, but that's going to be hard.

Nonetheless, just that we are in a simulation, I think there's no particular reason why we have to think the simulating universe has to be anything like ours.

You've said before that it might be, so you could think of it in turtles all the way down.

You could think of the simulating universe different than ours, but we ourselves could also create another simulating universe.

So you said that there could be these kind of levels of universes, and you've also mentioned this hilarious idea, maybe tongue in cheek, maybe not, that there may be simulations within simulations, arbitrarily stacked levels, and that we may be in level 42.

Along those stacks, referencing Hitchhiker's Guide to the Universe.

If we're indeed in a simulation within a simulation at level 42, what do you think level 0 looks like?

I would expect that level 0 is truly enormous.

I mean, not just, if it's finite, it's extraordinarily large finite capacity.

Maybe it's got some very high set There are 2 cardinalities that enables it to support just any number of any number of simulations.

So high degree of infinity at level 0 slightly slightly smaller degree of infinity at level 1.

So by the time you get down to us at level 42, maybe there's plenty of room for lots of simulations of finite capacity.

If the top universe is only a small finite capacity, then obviously that's going to put very, very serious limits on how many simulations you're going to be able to be able to get running.

So I think we can certainly confidently say that if we're at level 42, then the top level is pretty, pretty damn big.

So it gets more and more constrained as we get down levels, more and more simplified and constrained and limited in resources.

Feynman said, he said, there's plenty of room at the bottom.

We're still a number of levels above the degree where there's room for fundamental computing, physical computing capacity, quantum computing capacity at the bottom level.

So we've got plenty of room to play with and make, we probably have plenty of room for simulations of pretty sophisticated universes, perhaps none as complicated as our universe, unless our universe is infinite, but still at the very least for pretty serious finite universes, but maybe universes somewhat simpler than ours, unless of course, we're prepared to take certain shortcuts in the simulation, which might then increase the capacity significantly.

Do you think the human mind, us people, in terms of the complexity of simulation, is at the height of what the simulation might be able to achieve?

Like if you look at incredible entities that could be created in this universe of ours, do you have an intuition about how incredible human beings are on that scale?

I think we're pretty impressive, but we're not that impressive.

mean, I think kind of human beings are at a certain point in the scale of Intelligence which made many things possible, you know you get through evolution through single-cell Organisms through fish and mammals and primates and something happens once you get to human beings.

We've just reached that level where we get to develop language, we get to develop certain kinds of culture, and we get to develop certain kinds of collective thinking that has enabled all this amazing stuff to happen, science and literature and engineering and culture and, and so on.

So we had just at the beginning of that on the evolutionary threshold.

It's kind of like we just got there, you know, who knows a few thousand or tens of thousands of years ago.

So we're probably just at the very beginning for what's possible there.

So I'm inclined to think among the scale of intelligent beings, we're somewhere very near the bottom.

I would expect that, for example, if we're in a simulation, then the simulators who created us have got the capacity to be far more sophisticated.

If we're at level 42, Who knows what the ones at level 0 are like.

It's also possible that this is the epitome of what is possible to achieve.

So we as human beings see ourselves maybe as flawed, see all the constraints, all the limitations, but Maybe that's the magical, the beautiful thing.

Maybe those limitations are the essential elements for an interesting, sort of that edge of chaos, that interesting existence.

That if you make us much more intelligent, if you make us much more powerful in any kind of dimension of performance, maybe you lose something fundamental that makes life worth living.

So you kind of have this optimistic view that we're this little baby that then there's so much growth and potential.

Maybe what you're saying is consistent with what I'm saying.

I mean, we could still have levels of intelligence far beyond us, but maybe those levels of intelligence on your view would be kind of boring.

And we kind of get so good at everything that life suddenly becomes unidimensional.

So we're just inhabiting this 1 spot of maximal romanticism in the history of evolution.

You get to humans and it's like, yeah, and then years to come, our super intelligent descendants are gonna look back at us and say, those were the days when they just hit the point of inflection and life was interesting.

I am an optimist, so I'd like to think that, you know, If there is super intelligence somewhere in the future, they'll figure out how to make life super interesting and super romantic.

So what they're gonna do is they realize how boring life is when you're super intelligent, so they create a new level of a simulation and sort of live through the things they've created by watching them stumble about in their flawed ways.

So maybe that's, so you create a new level of a simulation and sort of live through the things they've created by watching them stumble about in their flawed ways.

So maybe that's, so you create a new level of a simulation every time you get really bored with how smart and-

This would be kind of sad though, because it would show the peak of their existence would be like watching simulations for entertainment.

It's like saying the peak of our existence now is Netflix.

a flip side of that could be the peak of our existence for many people having children and watching them grow.

Okay, you create a simulation, it's like creating a family.

Creating like, well, any kind of creation is kind of a powerful act.

Do you think it's easier to simulate the mind or the universe?

So I've heard several people, including Nick Blossom, think about ideas of, you know, maybe you don't need to simulate the universe, you can just simulate the human mind.

Or in general, just the distinction between simulating the entirety of it, the entirety of the physical world, or just simulating the mind?

Well, I think in some sense the answer is obvious.

It has to be simpler to simulate the mind than to simulate the universe, because the mind is part of the universe.

And in order to fully simulate the universe, you're gonna have to simulate the mind.

So unless we're talking about partial simulations.

And I guess the question is which comes first?

Does the mind come before the universe or does the universe come before the mind?

So the mind could just be an emergent phenomena in this universe.

It's not like creating a simulation perhaps requires you to program every single thing that happens in it.

It's just defining a set of initial conditions and rules based on which it behaves.

Simulating the mind requires you to have a little bit more, we're now in a little bit of a crazy land, but it requires you to understand the fundamentals of cognition, perhaps of consciousness, of perception of everything like that, that's me, that's not created through some kind of emergence from basic physics laws, but more requires you to actually understand the fundamentals of the mind.

How about if we said to simulate the brain rather than the mind?

To simulate the universe, at the very least, you're gonna have to simulate the brains as well as all the other physical systems within it.

And it's not obvious that the problems are any worse for the brain than for, it's a particularly complex physical system, but if we can simulate arbitrary physical systems, we can simulate brains.

There is this further question of whether when you simulate a brain, will that bring along all the features of the mind with it?

And that's something philosophers have argued over for years.

My own view is if you simulate the brain well enough, that will also simulate the mind.

But yeah, there's plenty of people who would say no.

You'd merely get like a zombie system, a simulation of a brain without any true consciousness.

But for you, you put together a brain, the consciousness comes with it, arise.

My view is roughly that, yeah, what is responsible for consciousness, it's in the patterns of information processing and so on, rather than say the biology that it's made of.

There's certainly plenty of people out there who think consciousness has to be say biological.

So if you merely replicate the patterns of information processing in a non-biological substrate, you'll miss what's crucial for consciousness.

I mean, I just don't think there's any particular reason to think that biology is special here.

You can imagine substituting the biology for non-biological systems, say silicon circuits, that play the same role.

The behavior will continue to be the same.

And I think just thinking about what is the true, when I think about the connection, the isomorphisms between consciousness and the brain, the deepest connections to me seem to connect consciousness to patterns of information processing, not to specific biology.

So I at least adopted as my working hypothesis that basically it's the computation and the information that matters for consciousness.

Same time, we don't understand consciousness, so all this could be wrong.

So the computation, the flow, the processing, manipulation of information, the process is where the consciousness, the software is where the consciousness comes from, not the hardware.

The patterns of information processing, at least in the hardware, which we could view as software.

It may not be something you can just like program and load and erase and so on in the way we can with ordinary software, but it's something at the level of information processing rather than at the level of implementation.

you think of the experience of self, just the experience of the world in a virtual world, in virtual reality?

Is it possible that we can create sort of offsprings of our consciousness by existing in a virtual world long enough?

So yeah, can we be conscious in the same kind of deep way that we are in this real world by hanging out in a virtual world?

Yeah, well the kind of virtual worlds we have now are interesting but limited in certain ways.

In particular, they rely on us having a brain and so on, which is outside the virtual world.

Maybe I'll strap on my VR headset or just hang out in a virtual world on a screen, but my brain and then my physical environment might be simulated if I'm in a virtual world.

But right now, there's no attempt to simulate my brain.

I might, there might be some non-player characters in these virtual worlds that have simulated cognitive systems of certain kinds that dictate their behavior.

But you know, mostly they're pretty simple right now.

I mean, some people are trying to combine, put a bit of AI in their non-player characters to make them smarter.

But for now, inside virtual worlds, the actual thinking is interestingly distinct from the physics of those virtual worlds.

In a way, actually, I like to think this is kind of reminiscent of the way that Descartes thought our physical world was.

There's physics and there's the mind and they're separate.

Now we think the mind is somehow connected to physics pretty deeply, But in these virtual worlds, there's a physics of a virtual world.

And then there's this brain, which is totally outside the virtual world that controls it and interacts it.

When anyone exercises agency in a video game, that's actually somebody outside the virtual world moving a controller, controlling the interaction of things inside the virtual world.

So right now in virtual worlds, the mind is somehow outside the world.

But you could imagine in the future, once we have developed serious AI, artificial general intelligence and so on, then we could come to virtual worlds which have enough sophistication, you could actually simulate a brain or have a genuine AGI, which would then presumably be able to act in equally sophisticated ways, maybe even more sophisticated ways inside the virtual world to how it might in the physical world.

And then the question's gonna come along, that'll be kind of a VR, a virtual world internal intelligence, and then the question is, could they have consciousness, experience, intelligence, free will, all the things that we have?

And again, my view is I don't see why not.

To linger on it a little bit, I find virtual reality really incredibly powerful.

Just even the crude virtual reality we have now.

Perhaps there's psychological effects that make some people more amenable to virtual worlds than others, but I find myself wanting to stay in virtual worlds

Really interesting, because I am totally addicted to using the internet and things on a desktop.

But when it comes to VR for the headset, I don't typically use it for more than 10 or 20 minutes.

There's something just slightly aversive about it I find.

So I don't, right now, even though I have Oculus Rift and Oculus Quest and HTC Vive and Samsung this and that.

The something about it, it's a both a combination of just imagination and considering the possibilities of where this goes in the future.

It feels like I want to almost prepare my brain for it.

I want to explore sort of Disneyland when it's first being built in the early days.

And it feels like I'm walking around almost imagining the possibilities and something through that process allows my mind to really enter into that world.

But you say that the brain's external to that virtual world.

But If you're in VR and you do brain surgery on an avatar, and you're gonna open up that skull, what are you gonna find?

You don't think it's possible to kind of separate them.

And I don't mean in a sense like Descartes, like a hard separation, but basically, do you think it's possible with the brain outside of the virtual, when you're wearing a headset, create a new consciousness for prolonged periods of time.

Really feel, like really experience, like forget that your brain is outside.

So this is, okay, this is gonna be the case where the brain is still outside.

But could living in the VR, I mean, we already find this, right, with video games.

They're completely immersive, and you get taken up by living in those worlds, and

So they're not completely immersive, they're just very immersive.

It's almost possible to really forget the external world, really, really immerse yourself.

You know, We've got pretty good memories.

Maybe you can stop paying attention to the external world, but this already happens a lot.

I go to work and maybe I'm not paying attention to my home life.

I go to a movie and I'm immersed in that.

So that degree of immersion, absolutely, but we still have the capacity to remember it, to completely forget the external world.

I'm thinking that would probably take some, I don't know, some pretty serious drugs or something to make your brain do that.

So, I mean, I guess I'm getting at, is consciousness truly a property that's tied to the physical brain?

Or can you create sort of different offspring copies of consciousnesses based on the worlds that you enter?

Well, the way we're doing it now, at least with a standard VR, there's just 1 brain.

Interacts with the physical world, plays a video game, puts on a video headset, interacts with this virtual world.

And I think we'd typically say there's 1 consciousness here that nonetheless undergoes different environments, takes on different characters, in different environments.

This is already something that happens in the non-virtual world.

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David Chalmers: The Hard Problem of Consciousness | Lex Fridman Podcast #69