StarTalk Radio - The Hard Problem of Consciousness with David Chalmers
Episode Date: November 1, 2024What exactly is consciousness, and why is it such a hard problem to solve? Neil deGrasse Tyson and co-hosts Chuck Nice and Gary O’Reilly take you deep into the mysteries of consciousness and objecti...ve reality, David Chalmers, a philosopher and cognitive scientist. NOTE: StarTalk+ Patrons can listen to this entire episode commercial-free here: https://startalkmedia.com/show/the-hard-problem-of-consciousness-with-david-chalmersThanks to our Patrons Jay, Gregory Aronoff, Tom B. Night, Barnsley, Glenn, Hibachi Flamethrower, Crescencio Maximilian joseph Martinez, Micheal Gomez, Matthew Deane, James, Joe Chillemi, Thomas van Cleave, Kelsey Plugge, Jeff Jones, William Hamilton, and Kevin Cosg. for supporting us this week. Subscribe to SiriusXM Podcasts+ on Apple Podcasts to listen to new episodes ad-free and a whole week early.
Transcript
Discussion (0)
Welcome to StarTalk, your place in the universe where science and pop culture collide.
StarTalk begins right now.
This is StarTalk Special Edition.
Neil deGrasse Tyson, your personal astrophysicist.
I got with me Chuck Knight. Chuck, baby.
Hey, what's happening?
All right, all right. How you doing, sir? I'm good, thank you. Gary O'Re Chuck Knight. Chuck, baby. Hey, what's happening? All right. All right.
How you doing, sir? I'm good. Thank you. Gary O'Reilly. Yeah. Thank you. Thank you. Love to
have you as my co-host here. It's a pleasure. Yeah. We're doing yet another episode on consciousness.
Yeah. When will we be done? When we know what we need to know. Okay. And so this could be going on
for a while. I mean, it's not just consciousness. It's know. Okay. And so this could be going on for a while.
I mean, it's not just consciousness.
It's consciousness and reality.
And our understanding and interpretation of reality. Exactly.
Filtered through our consciousness.
Totally.
So what show did you cook up today?
All right.
So we're heading for inner space rather than outer space.
Inner space.
I love it.
And consciousness, as we've just discussed.
We continually think of it as, I suppose, a precious entity.
We feel like we're above others on the planet, other beings.
Yes.
Say that to your cat.
I was going to say.
Don't start me on catitude.
Please don't go there.
Yeah, we think we're in charge of the cats.
It's the opposite.
I mean, for hundreds and thousands of years,
the greatest thinkers have grappled with it.
They've grappled with each other as regards to explaining it.
There are a handful of theories in existence,
but apparently it's a hard problem, which is a clue.
So what is consciousness?
What makes it?
Once we've conquered that particular mountain,
we will dive down a rabbit hole of simulation, theory, singularity,
and virtual reality. It's going to be fun. And to join us, we have Professor of Philosophy and
Neuroscience at NYU. He is an Australian philosopher and cognitive scientist, also an author,
Reality Plus and The Conscious Mind are two of his many books. He gave us phrases,
the hard problem of consciousness
and philosophical zombies along the way.
Please, David Chalmers.
David, welcome back to StarTalk.
And you're just down the street at NYU,
New York University.
Just right up here on the C train.
There you go.
Simplicity.
Welcome.
Now, why do we need you to say that consciousness is a hard problem?
Isn't that just obvious?
So why do we need a decorated professor of the field to assert that?
Totally obvious.
And when I first said this, I just said, okay, well okay I was just giving the thing a labels that everybody knows but who was to guess that the the
label would would catch on sometimes it's just a helpful to to say the
obvious actually you know the idea that consciousness pose poses a hard problem
we were talking about Newton before the show. You can actually find it in Newton.
At one point he says, the way that colors mix optically and produce a certain experience is not so easy.
He says it's not so easy, E-A-S-I-E.
And he says, you know, the way that all we understand this stuff objectively and say how the brain processes visual inputs,
but then it gives you the experience of a color.
That amazing pink shirt.
Yeah, go coral.
Magenta.
Yeah.
Where does that experience of pink come from?
As Newton said, not so easy.
King salmon.
Not farm raised.
King salmon. You reduce me to this kind of king salmon. Right, right. not so easy. King salmon. Not farm-raised. King salmon.
You reduce me to this kind of king salmon.
Right, right.
Good for you.
Wild caught.
Yeah, wild caught.
Reduce me to food stock.
Where does the experience of king salmon come from?
Envision, that is what Newton said, not so easy.
Okay, so David, had you instead called it
the easy problem of consciousness,
maybe we would have all figured it out by now.
Well, the easy problems were the problems of things you do, like how people respond, what they say.
So what is consciousness? Put it on the table.
Subjective experience.
Consciousness is anything you experience directly from the first-person point of view.
I think of it like the inner movie of the mind.
It's a movie, but it's got images and sounds like a regular movie,
but it's got sensations of your body.
It's got smell. It's got taste.
It's got emotions. It's got thinking,
all running through this inner soundtrack of your mind.
And that allows your consciousness to be distinct and unique from others
because the world as you receive it
Will could be very different from how someone else receives that very same world sounds like a problem
Is this where biases come in in the terms of how you
Receive and accept any information that comes to we all experience it subjectively in a different way.
Some things may be in common.
Maybe when we look at an image, the shape,
maybe our experience of that rectangle might be the same,
but the emotions that it brings on
may be totally different for me and for you.
Now, suppose we're running that same input
through a measurement device,
and then the device comes up with a conclusion.
And no matter how you put the information through, it reaches the same conclusion.
Yet somehow when we look at it, we see something different.
Who do you trust then?
The person or the device?
Yes.
I don't know if the device is like specialized.
It's a thermometer.
Right.
Let's say it's a thermometer.
It says 79 degrees. I'm going with the device. I'm going with the device is like specialized, it's a thermometer. It says 79 degrees.
I'm going with the device.
I'm going with the device too.
We're sitting together here.
I get this.
But I'm going with the device.
Me too.
It's like, you tell me it's 79 degrees.
No, I'm going to trust the thermometer.
There's a famous quote.
No science achieves maturity without a system of measurement.
And we do not have the measurement system for consciousness, actually.
Which renders it immature scientifically relative to other fields, where we have petri dishes
and methods and tools.
So you have a hard problem.
How about that?
Oh my God.
That was just proud that it was hard.
Oh my God.
I walked into that, didn't I?
You know, years ago, I went along to a conference and told everyone that I'd invented a measuring device for consciousness,
the consciousness meter, made with a combination of neuromorphic engineering, transpersonal psychology, and quantum gravity.
And then I pulled out my consciousness meter, and it looked kind of like a hairdryer
Back in the 90s, I would have called I would have called bullshit on your second half of that first sentence
So whereabouts in the brain do you think we are
Fermenting this consciousness. Well, this is one of the big debates which is going on.
What are the neural correlates of consciousness,
which is the bit of the brain which is active in a way
which is most directly connected to your consciousness.
And there's actually, even among neuroscientists,
there's a very lively debate between people who think it's in the,
say, for visual consciousness, people who think it's in the sensory areas.
Like the visual cortex.
Exactly, visual cortex back there.
Or prefrontal cortex, front of the brain, the areas associated more with thinking and judgment.
Just a question.
What's the difference between your prefrontal cortex and your frontal cortex?
Frontal cortex is a little bit more...
It's a little less front than the prefrontal cortex.
See? It's a little less front than the prefrontal cortex.
Okay. When we look at brain structures compared among other animals,
let's say mammals, to keep it in the family, presumably we have a bigger frontal cortex than other mammals,
and we can see what's going on in that,
and thereby decide that we have certain capacity for thought
that other animals do not.
Is that a fair way of saying it?
People who put consciousness in prefrontal cortex
are probably going to say that consciousness
is not so widespread
in the animal kingdom.
In the animal kingdom.
Whereas people who think
it's in the sensory cortices,
we get those throughout
the animal kingdom.
So maybe much,
you know,
like is a fish conscious?
Well, you know,
fish don't have any kind
of developed prefrontal cortex.
Yeah.
I'm going to say,
judging from the look
in their eyes,
I'm going to go out
on a limb and say no.
They know when a shulk's around.
Well, that's true.
I have a question.
Can you tell me what creates consciousness?
Is it emergent in the evo-bio sense, where you have an organism that has certain properties, but
only either en masse with other animals, like flocking of birds, or some other feature that
was not really intended. It just emerged from other features that were necessary for survival.
So is consciousness emergent, or do you think it specifically evolved?
Ooh.
It's in some sense emergent.
I mean, this word emergence gets used in so many different ways.
And sometimes it's like magic word.
It's like, I don't really understand it.
Anything we don't know.
I'll say it's emergent.
I like magic words.
Give me my magic word for the day.
In some sense, consciousness clearly emerges from the brain.
You get a brain that develops and consciousness comes along.
As the brain develops, consciousness gets more and more complex.
So there's some kind of connection there.
But can we tell a story about how consciousness was selected for in evolution?
No one has a good answer to that right now.
There are ideas out there.
Yeah, we needed consciousness for control,
for decision-making, for reflection.
But so far, no one has told a good story
about why you need to have consciousness to do those things.
Why couldn't a big, complicated computer do that without consciousness?
Is it really consciousness,
or are we talking about levels of consciousness?
Because I think that there are
definitely animals that have consciousness. I mean, a dog, for instance, you see it has emotion.
You see that it has a reaction to sensory data, just like we do. You see that it responds to
commands and pain and everything. But you look at a baby and if you didn't know any,
thing but you look at a baby and if you didn't know any if you never saw a baby before and you saw this thing this glob of human thing just sitting there like making these crazy faces
has no control of its limbs or you wouldn't necessarily say well that's a conscious thing
it's actually thinking about anything you you know you are totally right there are levels of
consciousness in in babies
and we're still arguing
about what they are.
I mean,
a long time ago,
people used to not give
anesthetics to babies
when they were
getting circumcised
because they thought
they couldn't feel pain.
Tell me about it.
No,
I'm joking.
I remember that day well,
sir.
These days,
we think babies feel pain
and we think they can
have some basic
visual experience
especially my wife who works on this stuff claudia passos is a leading expert on consciousness and
infants there's still an argument like can a baby have the experience of thinking right of deciding
of agency the general moral from what i can tell for the last few years is babies are a whole lot
more sophisticated than we thought they were david isn't that true for every single animal that we've studied in more depth than in the
past?
We are recovering greater levels of neurocomplexity in their conduct behavior than any previous
generation thought.
Is that true for every animal?
Yeah, this is absolutely the trend to say over the years, we have thought more and more
animals are more and more cognitively complex.
As to the question of whether they're conscious, we used to think, okay, humans, a few primates, monkeys, apes.
These days, it's like pretty much every mammal, probably birds, probably reptiles, are arguing about fish and octopuses.
It sounds like we're clawing our way out of our own ego.
Exactly.
How about that?
But the singularity of our presence in the animal kingdom is being challenged by further research into the conduct of animals. You've seen that YouTube video of the magpie bird where it's got the container of water that's filled up to the top,
and it drinks the water until the beak can't reach the water anymore.
It walks away, comes back with a pebble,
drops the pebble in,
raises the level,
and then it drinks.
And it does that three or four times.
So it has a clear understanding of volume displacement.
It has a clear understanding of Archimedean principles.
Okay.
Hello, I'm Vicki Brooke Allen, and I support StarTalk on Patreon.
This is StarTalk with Nailed Grass Tyson. But go back to Chuck's point about levels of consciousness.
When we sleep, when we're unconscious, when we're in a coma,
and if you put us under general anaesthetic,
do we not have varying levels of consciousness at different times?
The idea behind the anaesthetic is to wipe out consciousness completely.
And does it?
Very hard to test whether it absolutely does this.
At one point in the 1970s, for example, people put some kind of a rubber band around the
arm so the anesthetic didn't make it that far.
And then they said, if you hear me, please move your hand.
And what do you know?
The hand could move.
So then it's like that kind of anesthetic was maybe working partly just to paralyze you.
These days, okay, they work a lot harder to knock out
not just action, not just pain and awareness,
but it's hard to know that it's gone for sure.
Even when we're asleep, when we're dreaming,
there's certainly a level of consciousness there.
Isn't our consciousness altered in our dreams?
It's a different state of consciousness, for sure.
Psychedelics, they alter your consciousness.
Meditation, it alters your consciousness.
Yeah.
I'm so glad we have science to obtain an objective reality of the world.
If it all depended on the human brain, forget it.
We'd still be in the caves.
Did I just insult your entire field?
No, it's okay. Okay. But we can study what's different in the brain, in it. We'd still be in the caves. Did I just insult your entire field? No, it's okay.
Okay.
But, you know, we can study what's different in the brain
in these different states of consciousness,
and that is one of the most exciting advances
over the last 30 years.
I mean, psychedelics used to just be,
oh, my God, it's all just, you know, mystical wondrousness.
Right, I'm just, look at the colors and all that.
Now we can actually see what's happening in the brain
when you take a psychedelic.
So, David, you published a paper recently on AI and consciousness.
What was that?
Yeah, I got invited to give a talk, actually, to all the AI people at their big annual conference
on this controversial issue of whether current AI systems could be conscious.
I called it, Could a Large Language Model Be Conscious?
Large Language Model, like ChatChamp.
Exactly.
And I argued, probably they it- Large language model like chat chat. Exactly. Yeah.
And I argued probably they're not conscious right now,
but give it 10 years and they may well be.
Yeah.
Or they're conscious right now
and they're just not letting us know.
Yeah.
Just waiting to take over the world.
Just waiting to take it over, babe.
What are we if we don't have consciousness,
but we're still doing and being, what you've coined the frame philosophical zombies.
Is that what that's kind of leading to?
Yeah, I think therefore I brains.
This is a philosophical thought experiment about a creature which is as much like us as possible but lacks consciousness entirely.
Not quite like the zombies in the Hollywood movies,
because they behave quite unlike us,
and maybe they even have some conscious experiences
when they eat their victims' brains.
I love the taste of those brains.
But so the philosophical zombie,
one way to think about this is just say
you had a computer simulation of your brain in your body,
and maybe behaving just like you,
would it be conscious?
It's not obvious.
Many people think that such a creature would have no conscious experience at all.
And then that kind of is a way to, it's a hypothetical thought experiment.
But what it does is raises the question, why aren't we zombies?
Evolution produced us based on all the smart and sophisticated things we can do.
Why couldn't evolution just have produced philosophical zombies that act like us?
Well, we actually have produced the zombies the way you're talking about in AI.
You can speak to an AI now via computer.
So you don't know you're talking to an actual computer,
and it will speak to you as if it were a person.
You would not know that the thing you're talking to
doesn't have...
Well, it's the Turing test.
Right.
It is precisely the Turing test.
AI systems are getting very, very close
to passing the Turing test.
By the way, 50 years ago,
they already said it passed the Turing test
and then moved the goal lines.
So the goal lines have been systematically
getting moved to greater and greater complexity
before anyone decides that AI has achieved consciousness.
But it would have blown away Alan Turing,
even the first round.
Because I'm old, and we're maybe the same age-ish.
Eliza.
Remember, Eliza was one of the first computer programs
that understood language.
Simulated a psychotherapist.
Yes, yeah, basically a therapist.
You type in the commands.
There was no audio back then, so you just type it in.
Say, hi, Eliza.
How are you?
I'm fine.
Tell me about yourself.
Well, you know, I left home, you know, five years ago.
Tell me about your parents.
So Eliza would come back to you with these questions to get you to loosen up and talk about your psychological
state.
Like a real therapist.
Like a real therapist.
Joseph Weizenbaum, who invented ELIZA, the story goes that his secretary talked to ELIZA
over her lunch break and at the end of it said, this is the first person who's ever
really understood me.
Wow.
Oh no.
She needed more friends.
You're on record as saying the language AI will probably gain consciousness within 10 years.
Is that shrinking that timeline?
It is, as they're doing more and more impressive things.
What is it about it that does not count as consciousness today,
that you're waiting for it to do in the future?
Again, I'm tracking the goal lines that are continually moved forward.
So tell me. It's very close at least to passing the Turing test.
They've done some actual versions of the Turing test, just five minute versions, and people
take some versions of GPT-4 to be human more than 50% of the time.
So getting close to passing a Turing test.
That's behavior.
I think we're still looking for a couple of things in the internal dynamics of these systems.
Oh, whether it can beat us at Jeopardy and Go and chess?
Oh, it already did that.
We do move the goalpost.
You're constantly moving the goalpost.
Admit it.
I did my PhD in an AI lab 30 years ago.
If you'd told us then that we would have systems
that can carry on a conversation like this,
we'd say, conscious for sure.
That's what I'm saying.
Please don't hit the goalpost.
He's just letting me know that I'm conscious.
Tell me about these goalposts.
What new goal line is not yet reached?
I think people look at the internal processes
in these current AI systems,
and they say, do they have what goes along
with consciousness in a human?
For humans, we think, for example,
feedback processing is super important
for consciousness to get some kind of reflection
on your earlier states and so on.
Right now, in these language models,
it's all feed-forward.
Introspection, for example, is one.
Memory, even any form of memory,
would require, basically, feedback. These form of memory would require basically feedback.
These language models are essentially feed-forward systems.
Information gets passed from input to output.
It doesn't circulate back very much.
It doesn't need to circulate because it has access to all knowledge.
So it has bypassed even that as a need.
So now you can't fault it for not needing what you need,
what we need to declare ourselves
Conscious when it doesn't even need that but people say that at least opens up the possibility now that since it's doing it in a way
Which is unlike the way that we do it and that we are the one case
We know of humans are the one case we know of that are conscious
Then maybe this could be doing in a sufficiently different way that it's a philosophical zombie
We have right now the benchmark for consciousness
because humans are the only system we know.
Okay, so you can call it a philosophical zombie
rather than a higher consciousness entity.
And where does perception come into this?
Because that's where we kind of started.
Computers don't perceive, they actually observe.
So even if we did have all the knowledge in the world capable of running through our brains, each one of us would experience that differently based on the perceptions that we have of who we are, our relationship to the world, and our relationship to the information that we're receiving.
I declare that we think of, I don't want to speak for you, but typically we speak of consciousness as a feature,
not a bug of human existence, a feature. And so something to be praised that other animals do not
have. And in the example you're giving, AI is not susceptible to perception.
Correct.
Why do we now deny it a yet higher level of consciousness and say, yeah, it's got us beat?
You're saying that that's a benefit, to be in a position where you're still not conscious
because you're not susceptible to errors of interpretation as we are.
Back in my office here, I have a replica of Van Gogh's Starry Night.
Yes.
So if Van Gogh himself had been AI,
it would have been an exact representation
of the scene in front of him in 1889.
Right.
Okay, and it's not.
Right.
It's what that scene felt like to him.
Right.
So I'll give you that.
AI is not going to do that unless we tell it.
Right.
That's my point.
We can train it on Van Gogh
and it can give you all the Van Gogh paintings
you like.
But then it is an exact
representation of Van Gogh.
He wouldn't have made that
out of whole cloth.
Yeah.
Can we infer
consciousness on AI
until we absolutely know
how to define
consciousness itself?
Thank you.
And to have some kind
of operational criteria.
The funny thing is
our best operational criterion for consciousness in humans humans at least, is verbal report.
To know whether someone's conscious, you ask them.
To know what they're conscious of, you ask them.
I think, therefore, I am.
But in an AI system, the current AI systems, unfortunately, this has become useless as a criterion.
Because, yeah, sure, they will tell you that for a while they were all going around saying they were conscious,
and then for a while the tech companies made sure they didn't say that.
They taught them to lie.
I am merely a language model for open AI.
But anyway, this is now just a function of how they're trained.
So Neil tells us everything is mathematics.
So are we going to find ourselves with a t-shirt equation that can solve consciousness?
I mean, for a lot of people, this is one of the potential holy grails here.
Finding laws of consciousness so simple, we could write them on the front of a t-shirt,
and maybe with some beautiful mathematical expression.
Okay, so we've had Einstein give us the theory of relativity and change the way we see the universe, right, and things within it.
Penrose has gone into quantum mechanics with this ORC, O-R theory of his.
How was Roger Penrose a theoretical astrophysicist?
How was he received in your community when he published his book on consciousness, linking it to the quantum?
Well, it was very helpful in some ways. It got a lot of very smart people interested
in consciousness. Because it went to anchor it in laws of physics.
Yeah. His approach was to bring in quantum mechanics and furthermore,
non-standard quantum mechanics, non-algorithmic versions of quantum mechanics that went
way beyond what was
consensus even in physics. Then he combined it with some complicated biology, like the biology
of microtubules in the cell walls of neurons, very controversial in neuroscience. So I would say,
look, it's creative, it's brilliant because it's Penrose, but it's totally speculative,
totally controversial, and ultimately not well-received by neuroscientists.
Not just because he's an outsider,
but because they actually did a legitimate analysis.
They said that microtubules, your average neuroscientist...
I don't know what a microtubule is.
It's something inside the cell wall of a neuron...
It's a microtube.
...that Roger Penrose...
Dude, even I know this.
So quantum computing in the brain, basically.
Oh, okay.
And this was going to be wave function collapse and microtubules was going to be responsible
for the conscious.
Plus, I think the fundamental feature of quantum physics is the probabilistic nature of the
reality that it underpins.
And so it would allow you even possibly to have a perception of free
will because there's a probabilistic firing of neurons, right, triggered by
this quantum wave function. Okay, so that's as I understood it. I hope I didn't...
Is that the brain is kind of a prediction machine or is that just really...
For Penrose, the biggest thing was he thought the human mathematicians
can do things that no computer
could ever do and he used
Gödel's theorem that
no formal system can ever be
complete and consistent to argue
for that point and he made
a philosophical argument for why we have
to do these special and then he said
therefore we need new physics
that goes beyond anything computable. And he said, let's look to a theory of quantum gravity. And now we're getting
to Neil's territory. Right. So, Gertl studied the system of definitions that comprise math.
Okay. Okay. Okay. It turns out it applies to much more than math,
if you really think about it.
It also applies to keeping your belly nice and flat.
Sorry.
That's a different hurdle.
So we know that one plus one is two,
and two plus two is four.
Right.
And there are rules that get you there, okay?
So you can ask,
can mathematics be constructed
as a completely self-consistent set of rules okay where any rule
has a rule before it that is consistent with the other rules can you do this and he concluded
it's not just because he pulled it out of his ass he can show that at some point in mathematics
you just have to make something up and declare it to be true.
And you have no ability to prove that it's true.
Okay.
You have to assert it.
And out of that comes the rest of everything else.
Oh, wow.
And so this was shocking.
Because something with the logic of mathematics.
Right.
Yeah, this proves that.
And this is only true because I can prove it.
You keep doing that
all the way down,
you reach a point
where somebody's just
sitting there up on a throne
saying,
this is so.
So let it be written.
So let it be done.
Exactly.
That has to happen
at some point
for all the rest.
You know who also did this?
You must know this.
The colored people.
Okay.
What colored people?
No, I didn't say colored people.
No day on the end.
Oh, I'm sorry. I was going was gonna say what black mathematician did this oh so we can say what color is the gentleman's shirt okay as we've
decided and i said it's it's the color of king salmon king salmon well what color is the color
of king salmon the king salmon no then you're gonna say it's kind of like let's say it was It's the color of King Salmon. King Salmon. Well, what color is the color of King Salmon? The King Salmon.
No, then you're going to say it's kind of like, let's say it was blue.
As you say, it was kind of violet.
Well, what color is violet?
And then you can go to like the flower that's violet.
That's a violet.
Okay, that's a violet.
Well, what color is that?
Right?
You keep doing this and you reach a point where somebody just has to declare it.
At some point, you cannot reduce it any further.
You cannot reduce it.
You just have to declare.
You got to just say this is it.
We agree that this is red and then you take it any further. You cannot reduce it. You just have to declare. You gotta just say, this is it. We agree that this is red,
and then you take it from there.
And both Penrose
and the color people
think that the people
who study color.
Pronounce that more cleanly.
Because we got,
I'm like,
Chuck will come upside your ass.
So, you know,
Penrose and the Negro.
Colored people.
They're beside.
The vision scientists
who study color.
And
the mathematicians who think
about consistency and
completeness, both
sometimes end up at this point where they argue there is
something special about
human consciousness.
Humans can have insights
into seeing that some mathematical
theorem is true.
Penrose thought in a way that no machine could know.
The people who study color say,
through studying the visual processes in the brain that process colors,
you can study all that,
and it still won't tell you what the experience of the color of King Salmon is like.
That is something you have to know subjectively. Oh. The feeling of the color of King Simon is like. That is something you have to know subjectively.
Oh.
The feeling of the color. That's what they're saying because the color affects you.
Yeah.
And that effect will be different.
You cannot know that unless you actually experience it yourself.
The subjective experience.
The subjective.
You have to have had the experience.
I'm affected by the blues and the greens in Van Gogh's Starry Night.
Okay.
I feel those colors. I feel those colors.
You feel those colors.
And if you just read a book about it or if you just read.
Wouldn't do anything.
You looked at an image of your brain processing all this,
that would not give you the experience of Starry Night. If it's going to take different thinking,
because we've spent thousands of years thinking in a certain way,
and if you want an analogue, linear manner,
what theories are out there right now that are thinking differently
and are looking like they might challenge this hard problem?
You know, there's no consensus on this,
but one radical view on the reductionist side of the equation
is to say there actually is no such thing as consciousness.
It's all an illusion generated by the brain.
Our brain makes us think that we have
these special properties and nothing
actually has them.
I'm in that camp for no reason.
I'm just thinking maybe we're all dancing around
something that doesn't really exist.
And then maybe it's just we want to believe
there's this special thing to make
us seem special.
So what's driving that? Is that the sort of thousand brains theory that Hawkins has?
What is that?
What is that, thousand brains?
Please, you're more- I don't know the thousand brains.
Oh, it's kind of like a cognitive mechanism.
Hawkins came up, Jeff Hawkins, apparently.
Oh, Jeff Hawkins, okay, yeah.
Came up with the thousand brains where it's not just one singular brain
that's doing this, but these are the compartments within the brain
and might be doing a disservice to his theory here. Probably am.
Are you talking about the construction of the brain itself?
So, like, inside your brain are just these
multiple layers of brain
and
somehow they all come together
is what gives you the consciousness. Models
within models. The brain has models
of the brain and it may be a misleading
model of the brain. I mean, is it just dark space
that's occupying up there and we shine a a misleading model of the brain. I mean, is it just dark space that's occupying
up there, and we shine a light because that's the thing
we need to look at right now, because it's not a Rolodex.
I know that for sure.
So where is it, and how is it?
So does it then
exist as we're thinking?
The brain builds very simple models of the
world. Maybe it models physics
of the world with a folk physics, which is
way simpler and different from
actual physics. You say folk physics?
Yeah, like common sense physics. It's like
Aristotle's physics. Things like
impetus and so on.
That may not actually exist.
Heavy things fall faster than lighter things because they're heavier.
I was about to say, some of that is wrong.
Aristotle was kind of stupid.
Very, very smart.
He's a smart guy.
Aristotle got hardly any physics correct. No one I'm joking. He's a smart guy. Aristotle got hardly
any physics correct.
No one was going to get it right
the first time.
In physics,
if someone makes a measurement
and gets a result,
and then someone else makes
the same measurement,
but gets a different result,
and someone gets
a different machine
to try to measure
the same phenomenon,
and they yet get
a different result,
but everybody thinks
there's a result, but none of the results agree.
That's usually evidence of no phenomenon at all.
And people are pulling things out of the noise of the data.
When there's no agreement.
And so what leads me to think maybe consciousness doesn't really exist in any way anyone thinks is because everybody's idea about
consciousness is different and does not comport and does not blend into a greater edifice
of an understanding of consciousness which leads me in this example of physics to possibly think
that there's no such thing as consciousness and we're just dancing around a maypole
and the pole is is not even there well i said it's early, and we're just dancing around a maypole, and the pole is not even there.
Well, I said it's early days,
but I also think there is a core of phenomena
on which people agree, on which we have data.
That's good to know.
Coming out of the neuroscience,
there's phenomena like blindsight,
where people can identify an object without consciousness,
forms of contrast between conscious and unconscious perception,
experiments on neural correlates of consciousness.
The trouble is the agreement is not yet on the wild fundamental theory.
Maybe that's not happening for another 50 years or 100 years.
Who's to say?
But there's the beginnings of a science there.
There are things we can agree on.
And the neuroscientists tend to be conservative
about this stuff.
Mostly, they're not the ones writing the book
that says, here is my solution to the problem.
Let's build it up a piece at a time
and we'll eventually get there.
And in all fairness, you're in a very new field
compared to other branches of science.
We have the benefit of six centuries
of births of smart people,
which includes Galileo, who died the same year Newton was born.
And so we had Newton, we had Einstein.
We had the benefit of smart people.
Platforms upon which to build.
Over the centuries.
And if you're just all coming at it now.
Yeah, let's do our conservative science,
and let's also build some speculation on top of it.
But let's realize that right now it is speculation.
Good. Thank you.
Okay.
We'll speculate that if there is quantum mechanics in the consciousness that we're connected to the universe with our consciousness.
With our wave functions.
That is totally a speculation.
But these speculations are great to think about.
I'm a philosopher.
I get paid to speculate.
So it's like…
Good for you.
Really?
I get paid for this? Yeah,'s like... Good for you. Really?
All I have is ideas.
Yeah, they do.
I don't need to perform any experiments, except for thought experiments.
That's so cool.
They pay me for thought experiments.
Wait, did your parents say, he wants to be a philosopher?
How's he going to pay his rent?
Thought experiments.
I'm a philosopher.
Did you bullshit today?
Did you think about bullshitting today?
There's the old joke about the dean who said, you know, bullshitting today?
There's the old joke about the dean who said, you know,
why the physics department?
Why are you more like the math department?
All they need is pens, papers, and trash cans.
Or it could be like the philosophy department.
All they need is pens and paper.
Really good.
That's a great joke.
I love that.
So if we detach from consciousness just for the moment,
I go back to Descartes, almost 1650,
where he's questioning the reality outside of himself
and throw it into the future and ask,
if reality is reality, is not virtual reality real,
whatever real may be?
People often use the latest technology of the day to raise questions about reality.
Descartes put these questions in terms of dreaming.
How can I know that I'm not dreaming right now?
And then he built the thought experiment of an evil demon.
How can I know that an evil demon isn't producing all these perceptions of the world?
As he would at that time.
Even though none of it is real.
These days, we ask exactly that same question by saying, basically,
how do you know you're not in a virtual reality right now?
Might you be in the Matrix?
Could we be in a computer simulation?
And suddenly that question is just kind of a contemporary way of expressing
Descartes' old question about reality.
Except, I mean,
let's be honest, you can put a mathematical value
on every single thing in the universe.
Even particles have, we
learned, I learned, they have a, what do you
call, half up or half down? Spin.
Spin up, spin. A charge, a mass.
A charge, a mass. So you could put a mathematical,
if you could put a mathematical value on every
single thing, you can make a
simulation of every single thing.
For sure.
Right.
And in virtual reality right now,
in the actual virtual reality systems we have right now,
they have complex simulations and models inside them
with bits that have values.
Let me pull some philosophy on you.
If we can represent reality on a computer,
because we can mathematically map everything that's going on,
then
philosophically,
does the question even matter?
Ooh! Because
at that point, the virtual
reality is the reality.
So what difference does it make?
Reality is reality.
Reality is reality no matter what.
I'm sympathetic with your point,
but there is a traditional philosopher's response
which goes something like this.
Just say your spouse was cheating on you
and you never discover it.
So you never know the difference.
First of all, I knew it.
I'm sneaky.
No, go ahead.
You never know, so it doesn't affect you
at all
but a lot of people
want to say
man that would suck
that would be really bad
even though
I don't know
and they have the same attitude
towards virtual reality
even though it seems
the same to me
my beliefs
about the world
are totally shattered
in the same way
they would be
by my spouse
cheating on me
so for those dumpster divers on our podcast, we actually interviewed Nick Bostrom, one
of the early advancers of the idea that we might be living in a simulation.
He's one of your people, right?
Yeah, he's a philosopher, wrote a classic article in 2003, basically giving a mathematical
argument that we should take this idea that we're in a simulation seriously.
So that was four years after the movie The Matrix came out.
Yeah.
I wonder if that inspired him.
Is that allowed?
Will a philosopher admit
that pop culture influenced their deepest thoughts?
I wrote an article on this stuff
called The Matrix as Metaphysics,
trying to,
they asked me to write an article
for The Matrix website back in the day.
Nice.
I wrote something,
and I just think it's one of my greatest philosophical ideas.
Good.
I published a book later on. Reality Plus.
Pop culture influencing everything.
And the key idea was if we're in the matrix, that doesn't mean everything we believe is wrong.
Rather, we're living in an it-from-bit universe.
Can you write that down?
We're living in a universe where the its, the tables, the chairs, the plants, the planets,
are all made of bits. Bits.
Processes in a computational system. If we're in a simulation, all of the its are made of bits,
which connects to John Wheeler's famous idea that in physics,
the basic its are all bits.
The difference is, not the difference, the further clarification is,
in the matrix, there is a layered reality because their consciousness
is contained within them just like it is within us but then it's connected to the matrix yeah so
what you're saying is if this were a virtual reality when all of the it's would be bits would
just mean that they're all constructed. There is no outside.
Yeah, well, there's the pure it from bit where the bits are the basic level.
And then there's also what I call the it from bit from it,
which is underneath the bits. Wait, wait, wait.
Okay.
Where exactly do I get green eggs and ham in this virtual reality?
You go up to the matrix.
You find a computer which is running this simulation,
and it's got some bits, and all of its bits are made of voltages in a circuit board,
so it's it from bit from it.
So what is the probability that we are in a simulation?
And if we are, are we nothing more than some super sophisticated ant farm
for a young being somewhere?
From a mischievous alien in his parents' basement programming us up.
We're a school project.
We're a school project
at a science fair
in some distant galaxy.
More likely,
it's a high-powered scientist
who set up a billion
simulations overnight.
It just left him running.
He's going to come back
in the morning,
gather up the statistics.
Oh my gosh.
And time dilation.
It would make more sense.
I don't want to know that. I didn't even say that. You just ruined it. Oh my gosh. You time dilation. That makes more sense. I don't want to know that.
You just ruined it.
You ruined it because guess what?
Don't shut it down. And that would explain the
multiverse and everything.
Oh my god.
That's awful. Maybe
Hegel once said that the end of history is when
the universe becomes conscious of itself.
So in this simulation idea, the moment we
realize we're in a simulation, that's
when they shut us down.
Don't shut us down.
Just like the Truman Show.
Oh my God! That's one of my
favorite episodes of Rick and Morty.
Where you saw that where he goes
to the microverse and then the microverse
they find the teenyverse.
But the microverse
actually powers his car. Yes, I remember this. Inside the battery. actually powers his car.
Yes, I bet it's inside the battery.
He is their god.
Just for a spaceship.
Yes, yes, yes.
So we spend how much of our life in virtual reality right now as people?
Some people spend half their time there, at least in video games.
That's one kind of virtual reality.
Are we not leap walking into a continuous virtual reality for some of us?
I think it's coming.
This is what Mark Zuckerberg wants, right?
The metaverse.
Rename his whole company after this.
By the way, in the metaverse, it's not just a matter of entertainment.
In the metaverse, you go to work in the metaverse.
You meet your friends in the metaverse.
You literally live your life.
Your entertainment, your entertainment.
Right now, the sensory experience in a virtual reality
isn't 100% complete as we know it.
How long before we can taste, we can smell,
we can have all these other sensory developments in VR?
Reaction.
I think it's probably getting there in coming decades.
I mean, right now, the vision and the
hearing are actually pretty good.
Not 100%, but I've got an Apple
Vision Pro, and the visual quality
is very, very, very, very
high. They're now developing augmented reality
glasses like the Orion ones
just announced by Meta. We're not going to be walking around with
big old headsets on like that in the future.
Surely they'll just... We've resisted that.
Hopefully in the end, contact lenses,
brain computer interfaces
to get taste and smell and touch working.
It's probably going to require
some direct brain computer interface
to stimulate the body representations directly,
the smell areas directly.
So basically the irony will be
that we're in a simulation
and we'll end up being in,
going into a simulation in a simulation
yeah we could be uh we may already be at level 42 and that will take us down to level 43 so david
you got to take us out of here so where what should we look forward to well i think on the
reality side we're going to be getting more and more immersive detailed detailed forms of reality.
And the question is going to arise for us,
are those technological realities, genuine realities?
I want to say eventually, yes. And there's also, we got exactly the same question about consciousness.
Our first topic, we're going to have AI systems,
artificial brains, artificial intelligences.
And the question is, will those be genuine, real consciousnesses?
And where they meet is the notion, which has been featured in multiple films,
where you upload your consciousness to a jar.
If we are going to be able to upload our consciousness,
is it going to be better to upload it into a synthetic biological intelligence
or into a silicon-based intelligence?
Or does that even matter?
Does that even, who cares?
Maybe it doesn't.
I mean, right now, the best, most efficient artificial digital technologies we have
is the silicon kind.
Biology, we just don't have the same kind of control over.
So I would predict that we'll probably, at least in the short term,
if we're uploaded, we'll probably, at least in the short term,
if we're uploaded,
we'll be uploaded onto digital processors in silicon.
If we're in a virtual reality,
that will also be a reality running on digital processors in silicon.
But yeah, what ultimately matters
is not what it's made of.
It's the computation.
It's what it can capable of.
It's the bits.
Yeah, why should that even matter?
I mean, if you told someone 30 years ago,
we have people walking around with two knees and hips, and they'd say, well, It's the bits. Yeah, why should that even matter? I mean, if you told someone 30 years ago, we have people walking around with two knees and hips,
and they'd say, well, it's not biological.
No, it's metal, right?
They would, who cares?
You can still run.
No, it's just the thinking that you can't replicate the brain.
Well, they're starting to find that they can take themselves in that direction.
Yeah, replicate the brain.
One philosopher wrote a paper on this years ago called,
it's not the meat, it's the motion. Nice. It's not the biology, it's not the flesh. I used wrote a paper on this years ago called it's not the meat it's the motion.
Nice.
It's not the biology
I used to say a similar saying
I'm not
not too unlike that.
It's a 1950s
We don't need to know
your version of it, Chuck.
Your phone's ringing.
All right, David
thanks for coming back
on StarTalk.
This has been yet another edition
of StarTalk Special Edition,
this time with Professor David Chalmers.
And your latest book, tell me.
Reality Plus, all about those questions about reality and consciousness.
Reality Plus.
Reality Plus.
What's with the plus?
There's Paramount Plus, Disney Plus.
You know, I was originally going to call it Reality 2.0,
and everyone was like, that's too naughty and naughty.
2.0.
So Reality Plus, okay, well okay it's a cliche the plus
yeah but at least it's a 2020s cliche and regular people can read this yeah
it's for anybody okay it's about an introduction to the great problems of
philosophy through the lens of technology nice nice one of you why do
you read the book solve theve the Problems, please.
Yeah.
There you go.
All right, Chuck,
good to have you.
Always a pleasure. Gary.
Pleasure, Neil.
We're doing it here.
All right,
Neil deGrasse Tyson here
for StarTalk.
As always,
I bid you
to keep looking up.