back to index

Sean Carroll: The Nature of the Universe, Life, and Intelligence | Lex Fridman Podcast #26


small model | large model

link |
00:00:00.000
The following is a conversation with Sean Carroll.
link |
00:00:02.700
He's a theoretical physicist at Caltech
link |
00:00:04.900
specializing in quantum mechanics, gravity, and cosmology.
link |
00:00:08.780
He's the author of several popular books,
link |
00:00:11.620
one on the arrow of time called From Eternity to Here,
link |
00:00:15.340
one on the Higgs boson called Particle
link |
00:00:17.820
at the End of the Universe,
link |
00:00:19.140
and one on science and philosophy called The Big Picture
link |
00:00:22.540
on the Origins of Life, Meaning, and the Universe Itself.
link |
00:00:26.340
He has an upcoming book on quantum mechanics
link |
00:00:28.700
that you can preorder now called Something Deeply Hidden.
link |
00:00:32.660
He writes one of my favorite blogs on his website,
link |
00:00:36.060
preposterousuniverse.com.
link |
00:00:37.980
I recommend clicking on the Greatest Hits link
link |
00:00:40.460
that lists accessible, interesting posts
link |
00:00:43.340
on the arrow of time, dark matter, dark energy,
link |
00:00:45.660
the Big Bang, general relativity,
link |
00:00:47.620
string theory, quantum mechanics,
link |
00:00:49.580
and the big meta questions about the philosophy of science,
link |
00:00:53.180
God, ethics, politics, academia, and much, much more.
link |
00:00:57.620
Finally, and perhaps most famously,
link |
00:01:00.300
he's the host of a podcast called Mindscape
link |
00:01:03.660
that you should subscribe to and support on Patreon.
link |
00:01:06.940
Along with the Joe Rogan experience,
link |
00:01:08.820
Sam Harris's Making Sense,
link |
00:01:10.500
and Dan Carlin's Hardcore History,
link |
00:01:13.100
Sean's Mindscape podcast is one of my favorite ways
link |
00:01:15.860
to learn new ideas or explore different perspectives
link |
00:01:18.820
and ideas that I thought I understood.
link |
00:01:22.140
It was truly an honor to meet
link |
00:01:24.660
and spend a couple hours with Sean.
link |
00:01:27.240
It's a bit heartbreaking to say
link |
00:01:28.980
that for the first time ever,
link |
00:01:30.540
the audio recorder for this podcast
link |
00:01:32.500
died in the middle of our conversation.
link |
00:01:34.940
There's technical reasons for this,
link |
00:01:36.320
having to do with phantom power
link |
00:01:38.380
that I now understand and will avoid.
link |
00:01:41.060
It took me one hour to notice and fix the problem.
link |
00:01:44.220
So, much like the universe is 68% dark energy,
link |
00:01:48.340
roughly the same amount from this conversation was lost,
link |
00:01:51.340
except in the memories of the two people involved
link |
00:01:54.220
and in my notes.
link |
00:01:56.320
I'm sure we'll talk again and continue this conversation
link |
00:01:59.940
on this podcast or on Sean's.
link |
00:02:02.420
And of course, I look forward to it.
link |
00:02:05.300
This is the Artificial Intelligence podcast.
link |
00:02:07.820
If you enjoy it, subscribe on YouTube, iTunes,
link |
00:02:11.060
support it on Patreon,
link |
00:02:12.520
or simply connect with me on Twitter at Lex Friedman.
link |
00:02:16.660
And now, here's my conversation with Sean Carroll.
link |
00:02:21.380
What do you think is more interesting and impactful,
link |
00:02:23.540
understanding how the universe works at a fundamental level
link |
00:02:26.860
or understanding how the human mind works?
link |
00:02:29.180
You know, of course this is a crazy,
link |
00:02:31.960
meaningless, unanswerable question in some sense,
link |
00:02:33.940
because they're both very interesting
link |
00:02:35.140
and there's no absolute scale of interestingness
link |
00:02:37.500
that we can rate them on.
link |
00:02:39.180
There's a glib answer that says the human brain
link |
00:02:41.140
is part of the universe, right?
link |
00:02:43.060
And therefore, understanding the universe
link |
00:02:44.420
is more fundamental than understanding the human brain.
link |
00:02:47.020
But do you really believe that once we understand
link |
00:02:49.580
the fundamental way the universe works
link |
00:02:51.500
at the particle level, the forces,
link |
00:02:53.740
we would be able to understand how the mind works?
link |
00:02:55.820
No, certainly not.
link |
00:02:56.660
We cannot understand how ice cream works
link |
00:02:58.740
just from understanding how particles work, right?
link |
00:03:01.060
So I'm a big believer in emergence.
link |
00:03:02.740
I'm a big believer that there are different ways
link |
00:03:05.300
of talking about the world
link |
00:03:07.900
beyond just the most fundamental microscopic one.
link |
00:03:11.180
You know, when we talk about tables and chairs
link |
00:03:13.860
and planets and people,
link |
00:03:15.120
we're not talking the language of particle physics
link |
00:03:17.300
and cosmology.
link |
00:03:18.380
So, but understanding the universe,
link |
00:03:20.860
you didn't say just at the most fundamental level, right?
link |
00:03:24.060
So understanding the universe at all levels
link |
00:03:26.740
is part of that.
link |
00:03:28.200
I do think, you know, to be a little bit more fair
link |
00:03:29.940
to the question, there probably are general principles
link |
00:03:33.980
of complexity, biology, information processing,
link |
00:03:38.500
memory, knowledge, creativity
link |
00:03:41.820
that go beyond just the human brain, right?
link |
00:03:45.620
And maybe one could count understanding those
link |
00:03:47.800
as part of understanding the universe.
link |
00:03:49.140
The human brain, as far as we know,
link |
00:03:50.480
is the most complex thing in the universe.
link |
00:03:54.300
So there's, it's certainly absurd to think
link |
00:03:57.420
that by understanding the fundamental laws
link |
00:03:58.860
of particle physics,
link |
00:04:00.340
you get any direct insight on how the brain works.
link |
00:04:02.860
But then there's this step from the fundamentals
link |
00:04:05.940
of particle physics to information processing,
link |
00:04:08.700
which a lot of physicists and philosophers
link |
00:04:10.820
may be a little bit carelessly take
link |
00:04:12.460
when they talk about artificial intelligence.
link |
00:04:14.620
Do you think of the universe
link |
00:04:18.020
as a kind of a computational device?
link |
00:04:21.300
No, to be like, the honest answer there is no.
link |
00:04:24.140
There's a sense in which the universe
link |
00:04:26.300
processes information, clearly.
link |
00:04:29.140
There's a sense in which the universe
link |
00:04:30.700
is like a computer, clearly.
link |
00:04:33.880
But in some sense, I think,
link |
00:04:36.500
I tried to say this once on my blog
link |
00:04:38.540
and no one agreed with me,
link |
00:04:39.360
but the universe is more like a computation
link |
00:04:42.360
than a computer because the universe happens once.
link |
00:04:45.060
A computer is a general purpose machine, right?
link |
00:04:46.900
That you can ask it different questions,
link |
00:04:48.700
even a pocket calculator, right?
link |
00:04:50.140
And it's set up to answer certain kinds of questions.
link |
00:04:52.980
The universe isn't that.
link |
00:04:54.340
So information processing happens in the universe,
link |
00:04:57.360
but it's not what the universe is.
link |
00:04:59.220
And I know your MIT colleague, Seth Lloyd,
link |
00:05:01.580
feels very differently about this, right?
link |
00:05:03.820
Well, you're thinking of the universe as a closed system.
link |
00:05:07.220
I am.
link |
00:05:08.060
So what makes a computer more like a PC,
link |
00:05:12.980
like a computing machine is that there's a human
link |
00:05:15.500
that every once comes up to it and moves the mouse around.
link |
00:05:19.100
So input.
link |
00:05:19.940
Gives it input.
link |
00:05:20.760
Gives it input.
link |
00:05:23.500
And that's why you're saying it's just a computation,
link |
00:05:26.300
a deterministic thing that's just unrolling.
link |
00:05:29.260
But the immense complexity of it
link |
00:05:32.220
is nevertheless like processing.
link |
00:05:34.420
There's a state and then it changes with good rules.
link |
00:05:40.140
And there's a sense for a lot of people
link |
00:05:41.660
that if the brain operates,
link |
00:05:44.420
the human brain operates within that world,
link |
00:05:46.460
then it's simply just a small subset of that.
link |
00:05:49.340
And so there's no reason we can't build
link |
00:05:52.500
arbitrarily great intelligences.
link |
00:05:55.560
Yeah.
link |
00:05:56.400
Do you think of intelligence in this way?
link |
00:05:58.660
Intelligence is tricky.
link |
00:05:59.580
I don't have a definition of it offhand.
link |
00:06:01.660
So I remember this panel discussion that I saw on YouTube.
link |
00:06:05.460
I wasn't there, but Seth Lloyd was on the panel.
link |
00:06:07.620
And so was Martin Rees, the famous astrophysicist.
link |
00:06:10.540
And Seth gave his shtick for why the universe is a computer
link |
00:06:13.780
and explained this.
link |
00:06:14.820
And Martin Rees said, so what is not a computer?
link |
00:06:19.140
And Seth was like, oh, that's a good question.
link |
00:06:22.000
I'm not sure.
link |
00:06:22.840
Because if you have a sufficiently broad definition
link |
00:06:24.960
of what a computer is, then everything is, right?
link |
00:06:28.360
And the simile or the analogy gains force
link |
00:06:32.140
when it excludes some things.
link |
00:06:34.380
You know, is the moon going around the earth
link |
00:06:36.260
performing a computation?
link |
00:06:38.620
I can come up with definitions in which the answer is yes,
link |
00:06:41.320
but it's not a very useful computation.
link |
00:06:43.820
I think that it's absolutely helpful
link |
00:06:46.140
to think about the universe in certain situations,
link |
00:06:49.620
certain contexts, as an information processing device.
link |
00:06:53.020
I'm even guilty of writing a paper
link |
00:06:54.860
called Quantum Circuit Cosmology,
link |
00:06:56.820
where we modeled the whole universe as a quantum circuit.
link |
00:06:59.260
As a circuit.
link |
00:07:00.100
As a circuit, yeah.
link |
00:07:01.340
With qubits kind of thing?
link |
00:07:02.860
With qubits basically, right, yeah.
link |
00:07:05.040
So, and qubits becoming more and more entangled.
link |
00:07:07.440
So do we wanna digress a little bit?
link |
00:07:09.660
Let's do it.
link |
00:07:10.500
It's kind of fun.
link |
00:07:11.340
So here's a mystery about the universe
link |
00:07:13.700
that is so deep and profound that nobody talks about it.
link |
00:07:16.880
Space expands, right?
link |
00:07:19.080
And we talk about, in a certain region of space,
link |
00:07:21.940
a certain number of degrees of freedom,
link |
00:07:23.620
a certain number of ways that the quantum fields
link |
00:07:25.540
and the particles in that region can arrange themselves.
link |
00:07:28.800
That number of degrees of freedom in a region of space
link |
00:07:32.220
is arguably finite.
link |
00:07:33.820
We actually don't know how many there are,
link |
00:07:36.660
but there's a very good argument
link |
00:07:37.820
that says it's a finite number.
link |
00:07:39.420
So as the universe expands and space gets bigger,
link |
00:07:44.900
are there more degrees of freedom?
link |
00:07:46.780
If it's an infinite number, it doesn't really matter.
link |
00:07:48.540
Infinity times two is still infinity.
link |
00:07:49.980
But if it's a finite number, then there's more space,
link |
00:07:53.480
so there's more degrees of freedom.
link |
00:07:54.420
So where did they come from?
link |
00:07:55.740
That would mean the universe is not a closed system.
link |
00:07:58.020
There's more degrees of freedom popping into existence.
link |
00:08:01.500
So what we suggested was
link |
00:08:03.460
that there are more degrees of freedom,
link |
00:08:05.340
and it's not that they're not there to start,
link |
00:08:07.980
but they're not entangled to start.
link |
00:08:10.860
So the universe that you and I know of,
link |
00:08:12.820
the three dimensions around us that we see,
link |
00:08:15.440
we said those are the entangled degrees of freedom
link |
00:08:18.100
making up space time.
link |
00:08:19.620
And as the universe expands,
link |
00:08:20.920
there are a whole bunch of qubits in their zero state
link |
00:08:25.180
that become entangled with the rest of space time
link |
00:08:28.140
through the action of these quantum circuits.
link |
00:08:31.180
So what does it mean that there's now more
link |
00:08:35.580
degrees of freedom as they become more entangled?
link |
00:08:39.300
Yeah, so.
link |
00:08:40.300
As the universe expands.
link |
00:08:41.660
That's right, so there's more and more degrees of freedom
link |
00:08:43.300
that are entangled, that are playing part,
link |
00:08:46.420
playing the role of part
link |
00:08:47.360
of the entangled space time structure.
link |
00:08:49.600
So the basic, the underlying philosophy is
link |
00:08:51.980
that space time itself arises from the entanglement
link |
00:08:54.620
of some fundamental quantum degrees of freedom.
link |
00:08:57.560
Wow, okay, so at which point
link |
00:09:00.820
is most of the entanglement happening?
link |
00:09:05.260
Are we talking about close to the Big Bang?
link |
00:09:07.460
Are we talking about throughout the time of the life?
link |
00:09:11.820
Throughout history, yeah.
link |
00:09:12.660
So the idea is that at the Big Bang,
link |
00:09:15.140
almost all the degrees of freedom
link |
00:09:16.780
that the universe could have were there,
link |
00:09:19.700
but they were unentangled with anything else.
link |
00:09:22.420
And that's a reflection of the fact
link |
00:09:23.900
that the Big Bang had a low entropy.
link |
00:09:25.620
It was a very simple, very small place.
link |
00:09:28.020
And as space expands, more and more degrees of freedom
link |
00:09:31.420
become entangled with the rest of the world.
link |
00:09:34.300
Well, I have to ask John Carroll,
link |
00:09:35.940
what do you think of the thought experiment
link |
00:09:37.880
from Nick Bostrom that we're living in a simulation?
link |
00:09:41.580
So I think, let me contextualize that a little bit more.
link |
00:09:44.980
I think people don't actually take this thought experiments.
link |
00:09:48.340
I think it's quite interesting.
link |
00:09:50.460
It's not very useful, but it's quite interesting.
link |
00:09:52.900
From the perspective of AI,
link |
00:09:54.500
a lot of the learning that can be done usually happens
link |
00:09:58.020
in simulation from artificial examples.
link |
00:10:00.580
And so it's a constructive question to ask,
link |
00:10:04.900
how difficult is our real world to simulate?
link |
00:10:08.240
Right.
link |
00:10:09.360
Which is kind of a dual part of,
link |
00:10:12.180
if we're living in a simulation
link |
00:10:14.100
and somebody built that simulation,
link |
00:10:16.420
if you were to try to do it yourself, how hard would it be?
link |
00:10:18.860
So obviously we could be living in a simulation.
link |
00:10:21.100
If you just want the physical possibility,
link |
00:10:23.000
then I completely agree that it's physically possible.
link |
00:10:25.420
I don't think that we actually are.
link |
00:10:27.380
So take this one piece of data into consideration.
link |
00:10:30.300
You know, we live in a big universe, okay?
link |
00:10:35.140
There's two trillion galaxies in our observable universe
link |
00:10:38.500
with 200 billion stars in each galaxy, et cetera.
link |
00:10:41.660
It would seem to be a waste of resources
link |
00:10:44.940
to have a universe that big going on
link |
00:10:46.540
just to do a simulation.
link |
00:10:47.540
So in other words, I want to be a good Bayesian.
link |
00:10:50.140
I want to ask under this hypothesis,
link |
00:10:52.940
what do I expect to see?
link |
00:10:54.960
So the first thing I would say is I wouldn't expect
link |
00:10:56.780
to see a universe that was that big, okay?
link |
00:11:00.340
The second thing is I wouldn't expect the resolution
link |
00:11:02.540
of the universe to be as good as it is.
link |
00:11:05.020
So it's always possible that if our superhuman simulators
link |
00:11:08.740
only have finite resources,
link |
00:11:09.900
that they don't render the entire universe, right?
link |
00:11:12.420
That the part that is out there,
link |
00:11:14.340
the two trillion galaxies,
link |
00:11:16.300
isn't actually being simulated fully, okay?
link |
00:11:19.640
But then the obvious extrapolation of that
link |
00:11:22.740
is that only I am being simulated fully.
link |
00:11:25.500
Like the rest of you are just non player characters, right?
link |
00:11:29.220
I'm the only thing that is real.
link |
00:11:30.520
The rest of you are just chat bots.
link |
00:11:32.780
Beyond this wall, I see the wall,
link |
00:11:34.320
but there is literally nothing
link |
00:11:36.020
on the other side of the wall.
link |
00:11:37.360
That is sort of the Bayesian prediction.
link |
00:11:39.300
That's what it would be like
link |
00:11:40.180
to do an efficient simulation of me.
link |
00:11:42.240
So like none of that seems quite realistic.
link |
00:11:45.700
I don't see, I hear the argument that it's just possible
link |
00:11:50.900
and easy to simulate lots of things.
link |
00:11:53.300
I don't see any evidence from what we know
link |
00:11:55.780
about our universe that we look like a simulated universe.
link |
00:11:59.340
Now, maybe you can say,
link |
00:12:00.180
well, we don't know what it would look like,
link |
00:12:01.980
but that's just abandoning your Bayesian responsibilities.
link |
00:12:04.520
Like your job is to say under this theory,
link |
00:12:07.660
here's what you would expect to see.
link |
00:12:09.500
Yeah, so certainly if you think about simulation
link |
00:12:11.660
as a thing that's like a video game
link |
00:12:14.340
where only a small subset is being rendered.
link |
00:12:17.740
But say the entire, all the laws of physics,
link |
00:12:22.740
the entire closed system of the quote unquote universe,
link |
00:12:26.540
it had a creator.
link |
00:12:27.780
Yeah, it's always possible.
link |
00:12:29.320
Right, so that's not useful to think about
link |
00:12:32.280
when you're thinking about physics.
link |
00:12:34.020
The way Nick Bostrom phrases it,
link |
00:12:36.220
if it's possible to simulate a universe,
link |
00:12:39.100
eventually we'll do it.
link |
00:12:40.500
Right.
link |
00:12:42.700
You can use that by the way for a lot of things.
link |
00:12:44.860
Well, yeah.
link |
00:12:45.700
But I guess the question is,
link |
00:12:48.540
how hard is it to create a universe?
link |
00:12:52.340
I wrote a little blog post about this
link |
00:12:53.820
and maybe I'm missing something,
link |
00:12:55.460
but there's an argument that says not only
link |
00:12:57.680
that it might be possible to simulate a universe,
link |
00:13:00.500
but probably if you imagine that you actually attribute
link |
00:13:05.980
consciousness and agency to the little things
link |
00:13:08.860
that we're simulating, to our little artificial beings,
link |
00:13:12.020
there's probably a lot more of them
link |
00:13:13.420
than there are ordinary organic beings in the universe
link |
00:13:15.500
or there will be in the future, right?
link |
00:13:17.420
So there's an argument that not only
link |
00:13:18.500
is being a simulation possible,
link |
00:13:20.760
it's probable because in the space
link |
00:13:23.560
of all living consciousnesses,
link |
00:13:24.960
most of them are being simulated, right?
link |
00:13:26.620
Most of them are not at the top level.
link |
00:13:28.860
I think that argument must be wrong
link |
00:13:30.540
because it follows from that argument that,
link |
00:13:33.100
if we're simulated, but we can also simulate other things,
link |
00:13:36.920
well, but if we can simulate other things,
link |
00:13:38.840
they can simulate other things, right?
link |
00:13:41.840
If we give them enough power and resolution
link |
00:13:44.320
and ultimately we'll reach a bottom
link |
00:13:45.980
because the laws of physics in our universe have a bottom,
link |
00:13:49.140
we're made of atoms and so forth,
link |
00:13:51.000
so there will be the cheapest possible simulations.
link |
00:13:55.100
And if you believe the original argument,
link |
00:13:57.700
you should conclude that we should be
link |
00:13:59.340
in the cheapest possible simulation
link |
00:14:00.940
because that's where most people are.
link |
00:14:02.660
But we don't look like that.
link |
00:14:03.620
It doesn't look at all like we're at the edge of resolution,
link |
00:14:06.860
that we're 16 bit things.
link |
00:14:09.540
It seems much easier to make much lower level things
link |
00:14:13.020
than we are.
link |
00:14:14.980
And also, I questioned the whole approach
link |
00:14:18.220
to the anthropic principle
link |
00:14:19.460
that says we are typical observers in the universe.
link |
00:14:22.340
I think that that's not actually,
link |
00:14:23.660
I think that there's a lot of selection that we can do
link |
00:14:27.340
that we're typical within things we already know,
link |
00:14:30.180
but not typical within all of the universe.
link |
00:14:32.280
So do you think there's intelligent life,
link |
00:14:35.800
however you would like to define intelligent life,
link |
00:14:37.860
out there in the universe?
link |
00:14:39.940
My guess is that there is not intelligent life
link |
00:14:44.660
in the observable universe other than us, simply
link |
00:14:48.820
on the basis of the fact that the likely number
link |
00:14:52.540
of other intelligent species in the observable universe,
link |
00:14:56.340
there's two likely numbers, zero or billions.
link |
00:15:01.500
And if there had been billions,
link |
00:15:02.580
you would have noticed already.
link |
00:15:05.300
For there to be literally like a small number,
link |
00:15:07.340
like, you know, Star Trek,
link |
00:15:09.380
there's a dozen intelligent civilizations in our galaxy,
link |
00:15:13.300
but not a billion, that's weird.
link |
00:15:17.340
That's sort of bizarre to me.
link |
00:15:18.500
It's easy for me to imagine that there are zero others
link |
00:15:21.020
because there's just a big bottleneck
link |
00:15:22.620
to making multicellular life
link |
00:15:24.980
or technological life or whatever.
link |
00:15:27.020
It's very hard for me to imagine
link |
00:15:28.580
that there's a whole bunch out there
link |
00:15:30.140
that have somehow remained hidden from us.
link |
00:15:32.300
The question I'd like to ask
link |
00:15:34.700
is what would intelligent life look like?
link |
00:15:38.140
What I mean by that question and where it's going
link |
00:15:40.500
is what if intelligent life is just in some very big ways
link |
00:15:47.260
different than the one that has on Earth?
link |
00:15:51.500
That there's all kinds of intelligent life
link |
00:15:53.900
that operates at different scales
link |
00:15:55.420
of both size and temporal.
link |
00:15:57.300
Right, that's a great possibility
link |
00:15:59.300
because I think we should be humble
link |
00:16:00.800
about what intelligence is, what life is.
link |
00:16:02.640
We don't even agree on what life is,
link |
00:16:04.020
much less what intelligent life is, right?
link |
00:16:07.020
So that's an argument for humility,
link |
00:16:08.980
saying there could be intelligent life
link |
00:16:10.860
of a very different character, right?
link |
00:16:13.620
Like you could imagine the dolphins are intelligent
link |
00:16:18.060
but never invent space travel
link |
00:16:20.500
because they live in the ocean
link |
00:16:21.460
and they don't have thumbs, right?
link |
00:16:24.180
So they never invent technology, they never invent smelting.
link |
00:16:27.860
Maybe the universe is full of intelligent species
link |
00:16:32.020
that just don't make technology, right?
link |
00:16:34.060
That's compatible with the data, I think.
link |
00:16:36.320
And I think maybe what you're pointing at
link |
00:16:39.840
is even more out there versions of intelligence,
link |
00:16:44.440
intelligence in intermolecular clouds
link |
00:16:47.560
or on the surface of a neutron star
link |
00:16:49.440
or in between the galaxies in giant things
link |
00:16:51.760
where the equivalent of a heartbeat is 100 million years.
link |
00:16:56.440
On the one hand, yes,
link |
00:16:58.080
we should be very open minded about those things.
link |
00:16:59.860
On the other hand, all of us share the same laws of physics.
link |
00:17:04.860
There might be something about the laws of physics,
link |
00:17:08.240
even though we don't currently know
link |
00:17:09.400
exactly what that thing would be,
link |
00:17:10.920
that makes meters and years
link |
00:17:16.160
the right length and timescales for intelligent life.
link |
00:17:19.880
Maybe not, but we're made of atoms,
link |
00:17:22.240
atoms have a certain size,
link |
00:17:23.780
we orbit stars or stars have a certain lifetime.
link |
00:17:27.280
It's not impossible to me that there's a sweet spot
link |
00:17:30.300
for intelligent life that we find ourselves in.
link |
00:17:32.200
So I'm open minded either way,
link |
00:17:33.800
I'm open minded either being humble
link |
00:17:35.280
and there's all sorts of different kinds of life
link |
00:17:37.080
or no, there's a reason we just don't know it yet
link |
00:17:39.280
why life like ours is the kind of life that's out there.
link |
00:17:42.080
Yeah, I'm of two minds too,
link |
00:17:43.320
but I often wonder if our brains is just designed
link |
00:17:47.200
to quite obviously to operate and see the world
link |
00:17:52.720
in these timescales and we're almost blind
link |
00:17:56.360
and the tools we've created for detecting things are blind
link |
00:18:01.200
to the kind of observation needed
link |
00:18:02.760
to see intelligent life at other scales.
link |
00:18:04.920
Well, I'm totally open to that,
link |
00:18:07.040
but so here's another argument I would make,
link |
00:18:09.240
we have looked for intelligent life,
link |
00:18:11.520
but we've looked at for it in the dumbest way we can,
link |
00:18:14.120
by turning radio telescopes to the sky.
link |
00:18:16.600
And why in the world would a super advanced civilization
link |
00:18:21.040
randomly beam out radio signals wastefully
link |
00:18:24.040
in all directions into the universe?
link |
00:18:25.440
That just doesn't make any sense,
link |
00:18:27.280
especially because in order to think
link |
00:18:29.100
that you would actually contact another civilization,
link |
00:18:32.020
you would have to do it forever,
link |
00:18:33.840
you have to keep doing it for millions of years,
link |
00:18:35.840
that sounds like a waste of resources.
link |
00:18:38.280
If you thought that there were other solar systems
link |
00:18:43.120
with planets around them,
link |
00:18:44.520
where maybe intelligent life didn't yet exist,
link |
00:18:47.000
but might someday,
link |
00:18:48.600
you wouldn't try to talk to it with radio waves,
link |
00:18:51.380
you would send a spacecraft out there
link |
00:18:53.600
and you would park it around there
link |
00:18:55.560
and it would be like, from our point of view,
link |
00:18:57.360
it'd be like 2001, where there was a monolith.
link |
00:19:00.700
Monolith.
link |
00:19:01.540
There could be an artifact,
link |
00:19:02.380
in fact, the other way works also, right?
link |
00:19:04.520
There could be artifacts in our solar system
link |
00:19:08.440
that have been put there
link |
00:19:10.480
by other technologically advanced civilizations
link |
00:19:12.280
and that's how we will eventually contact them.
link |
00:19:14.640
We just haven't explored the solar system well enough yet
link |
00:19:16.840
to find them.
link |
00:19:18.580
The reason why we don't think about that
link |
00:19:20.000
is because we're young and impatient, right?
link |
00:19:21.520
Like, it would take more than my lifetime
link |
00:19:24.000
to actually send something to another star system
link |
00:19:26.080
and wait for it and then come back.
link |
00:19:27.800
So, but if we start thinking on hundreds of thousands
link |
00:19:30.800
of years or million year time scales,
link |
00:19:32.720
that's clearly the right thing to do.
link |
00:19:34.600
Are you excited by the thing
link |
00:19:36.800
that Elon Musk is doing with SpaceX in general?
link |
00:19:39.360
Space, but the idea of space exploration,
link |
00:19:41.620
even though your, or your species is young and impatient?
link |
00:19:45.360
Yeah.
link |
00:19:46.200
No, I do think that space travel is crucially important,
link |
00:19:49.200
long term.
link |
00:19:50.800
Even to other star systems.
link |
00:19:52.500
And I think that many people overestimate the difficulty
link |
00:19:57.500
because they say, look, if you travel 1% the speed of light
link |
00:20:00.940
to another star system,
link |
00:20:02.020
we'll be dead before we get there, right?
link |
00:20:04.060
And I think that it's much easier.
link |
00:20:06.180
And therefore, when they write their science fiction stories,
link |
00:20:08.120
they imagine we'd go faster than the speed of light
link |
00:20:09.580
because otherwise they're too impatient, right?
link |
00:20:11.700
We're not gonna go faster than the speed of light,
link |
00:20:13.600
but we could easily imagine that the human lifespan
link |
00:20:16.020
gets extended to thousands of years.
link |
00:20:18.100
And once you do that,
link |
00:20:19.140
then the stars are much closer effectively, right?
link |
00:20:21.180
And then what's a hundred year trip, right?
link |
00:20:23.260
So I think that that's gonna be the future,
link |
00:20:25.820
the far future, not my lifetime once again,
link |
00:20:28.700
but baby steps.
link |
00:20:30.380
Unless your lifetime gets extended.
link |
00:20:32.420
Well, it's in a race against time, right?
link |
00:20:34.740
A friend of mine who actually thinks about these things
link |
00:20:37.340
said, you know, you and I are gonna die,
link |
00:20:40.460
but I don't know about our grandchildren.
link |
00:20:43.060
That's, I don't know, predicting the future is hard,
link |
00:20:45.940
but that's at least a plausible scenario.
link |
00:20:47.900
And so, yeah, no, I think that as we discussed earlier,
link |
00:20:51.820
there are threats to the earth, known and unknown, right?
link |
00:20:56.780
Having spread humanity and biology elsewhere
link |
00:21:02.580
is a really important longterm goal.
link |
00:21:04.940
What kind of questions can science not currently answer,
link |
00:21:08.900
but might soon?
link |
00:21:11.480
When you think about the problems and the mysteries
link |
00:21:13.860
before us that may be within reach of science.
link |
00:21:17.840
I think an obvious one is the origin of life.
link |
00:21:20.300
We don't know how that happened.
link |
00:21:22.780
There's a difficulty in knowing how it happened historically
link |
00:21:25.300
actually, you know, literally on earth,
link |
00:21:27.240
but starting life from non life is something
link |
00:21:30.500
I kind of think we're close to, right?
link |
00:21:32.420
We're really.
link |
00:21:33.240
You really think so?
link |
00:21:34.080
Like how difficult is it to start life?
link |
00:21:36.740
Well, I've talked to people,
link |
00:21:39.260
including on the podcast about this.
link |
00:21:41.780
You know, life requires three things.
link |
00:21:43.340
Life as we know it.
link |
00:21:44.220
So there's a difference with life,
link |
00:21:45.500
which who knows what it is,
link |
00:21:47.060
and life as we know it,
link |
00:21:48.140
which we can talk about with some intelligence.
link |
00:21:50.780
So life as we know it requires compartmentalization.
link |
00:21:53.840
You need like a little membrane around your cell.
link |
00:21:56.660
Metabolism, you need to take in food and eat it
link |
00:21:58.980
and let that make you do things.
link |
00:22:01.020
And then replication, okay?
link |
00:22:02.620
So you need to have some information about who you are
link |
00:22:04.620
that you pass down to future generations.
link |
00:22:07.880
In the lab, compartmentalization seems pretty easy.
link |
00:22:11.780
Not hard to make lipid bilayers
link |
00:22:13.780
that come into little cellular walls pretty easily.
link |
00:22:16.760
Metabolism and replication are hard,
link |
00:22:20.160
but replication we're close to.
link |
00:22:21.900
People have made RNA like molecules in the lab
link |
00:22:24.960
that I think the state of the art is,
link |
00:22:28.840
they're not able to make one molecule
link |
00:22:30.660
that reproduces itself,
link |
00:22:32.060
but they're able to make two molecules
link |
00:22:33.600
that reproduce each other.
link |
00:22:35.260
So that's okay.
link |
00:22:36.100
That's pretty close.
link |
00:22:38.060
Metabolism is harder, believe it or not,
link |
00:22:41.060
even though it's sort of the most obvious thing,
link |
00:22:42.900
but you want some sort of controlled metabolism
link |
00:22:44.940
and the actual cellular machinery in our bodies
link |
00:22:47.500
is quite complicated.
link |
00:22:48.660
It's hard to see it just popping into existence
link |
00:22:50.940
all by itself.
link |
00:22:51.780
It probably took a while,
link |
00:22:53.740
but we're making progress.
link |
00:22:56.100
And in fact, I don't think we're spending
link |
00:22:57.240
nearly enough money on it.
link |
00:22:58.580
If I were the NSF, I would flood this area with money
link |
00:23:01.780
because it would change our view of the world
link |
00:23:05.220
if we could actually make life in the lab
link |
00:23:06.780
and understand how it was made originally here on earth.
link |
00:23:09.420
And I'm sure it'd have some ripple effects
link |
00:23:11.160
that help cure disease and so on.
link |
00:23:12.940
I mean, just that understanding.
link |
00:23:14.380
So synthetic biology is a wonderful big frontier
link |
00:23:16.700
where we're making cells.
link |
00:23:18.940
Right now, the best way to do that
link |
00:23:21.100
is to borrow heavily from existing biology, right?
link |
00:23:23.620
Well, Craig Venter several years ago
link |
00:23:25.380
created an artificial cell, but all he did was,
link |
00:23:28.220
not all he did, it was a tremendous accomplishment,
link |
00:23:29.860
but all he did was take out the DNA from a cell
link |
00:23:33.180
and put in entirely new DNA and let it boot up and go.
link |
00:23:37.200
What about the leap to creating intelligent life on earth?
link |
00:23:43.420
Yeah.
link |
00:23:44.260
Again, we define intelligence, of course,
link |
00:23:45.860
but let's just even say Homo sapiens,
link |
00:23:49.860
the modern intelligence in our human brain.
link |
00:23:55.340
Do you have a sense of what's involved in that leap
link |
00:23:58.660
and how big of a leap that is?
link |
00:24:00.420
So AI would count in this, or do you really want life?
link |
00:24:03.300
Do you want really an organism in some sense?
link |
00:24:06.420
AI would count, I think.
link |
00:24:07.540
Okay.
link |
00:24:08.980
Yeah, of course, of course AI would count.
link |
00:24:11.020
Well, let's say artificial consciousness, right?
link |
00:24:13.460
So I do not think we are on the threshold
link |
00:24:15.500
of creating artificial consciousness.
link |
00:24:16.760
I think it's possible.
link |
00:24:18.180
I'm not, again, very educated about how close we are,
link |
00:24:20.300
but my impression is not that we're really close
link |
00:24:22.100
because we understand how little we understand
link |
00:24:24.820
of consciousness and what it is.
link |
00:24:26.460
So if we don't have any idea what it is,
link |
00:24:28.440
it's hard to imagine we're on the threshold
link |
00:24:29.780
of making it ourselves.
link |
00:24:32.500
But it's doable, it's possible.
link |
00:24:34.500
I don't see any obstacles in principle.
link |
00:24:35.960
So yeah, I would hold out some interest
link |
00:24:38.160
in that happening eventually.
link |
00:24:40.220
I think in general, consciousness,
link |
00:24:42.700
I think we would be just surprised
link |
00:24:44.420
how easy consciousness is once we create intelligence.
link |
00:24:49.060
I think consciousness is a thing
link |
00:24:50.540
that's just something we all fake.
link |
00:24:55.540
Well, good.
link |
00:24:56.380
No, actually, I like this idea that in fact,
link |
00:24:57.680
consciousness is way less mysterious than we think
link |
00:25:00.500
because we're all at every time, at every moment,
link |
00:25:02.620
less conscious than we think we are, right?
link |
00:25:04.500
We can fool things.
link |
00:25:05.460
And I think that plus the idea
link |
00:25:07.780
that you not only have artificial intelligent systems,
link |
00:25:11.180
but you put them in a body, right,
link |
00:25:12.980
give them a robot body,
link |
00:25:15.620
that will help the faking a lot.
link |
00:25:18.460
Yeah, I think creating consciousness
link |
00:25:20.980
in artificial consciousness is as simple
link |
00:25:25.140
as asking a Roomba to say, I'm conscious,
link |
00:25:30.020
and refusing to be talked out of it.
link |
00:25:32.780
Could be, it could be.
link |
00:25:33.820
And I mean, I'm almost being silly,
link |
00:25:36.740
but that's what we do.
link |
00:25:39.660
That's what we do with each other.
link |
00:25:40.940
This is the kind of,
link |
00:25:42.020
that consciousness is also a social construct.
link |
00:25:44.500
And a lot of our ideas of intelligence is a social construct.
link |
00:25:47.860
And so reaching that bar involves something that's beyond,
link |
00:25:52.820
that doesn't necessarily involve
link |
00:25:54.940
the fundamental understanding of how you go
link |
00:25:57.720
from electrons to neurons to cognition.
link |
00:26:02.500
No, actually, I think that is an extremely good point.
link |
00:26:05.060
And in fact, what it suggests is,
link |
00:26:08.660
so yeah, you referred to Kate Darling,
link |
00:26:10.540
who I had on the podcast,
link |
00:26:11.940
and who does these experiments with very simple robots,
link |
00:26:16.440
but they look like animals,
link |
00:26:18.060
and they can look like they're experiencing pain,
link |
00:26:20.740
and we human beings react very negatively
link |
00:26:23.380
to these little robots
link |
00:26:24.400
looking like they're experiencing pain.
link |
00:26:26.300
And what you wanna say is, yeah, but they're just robots.
link |
00:26:29.980
It's not really pain, right?
link |
00:26:31.700
It's just some electrons going around.
link |
00:26:33.080
But then you realize, you and I are just electrons
link |
00:26:36.300
going around, and that's what pain is also.
link |
00:26:38.380
And so what I would have an easy time imagining
link |
00:26:43.060
is that there is a spectrum
link |
00:26:44.740
between these simple little robots that Kate works with
link |
00:26:47.420
and a human being,
link |
00:26:49.420
where there are things that sort of
link |
00:26:50.940
by some strict definition,
link |
00:26:52.840
Turing test level thing are not conscious,
link |
00:26:55.460
but nevertheless walk and talk like they're conscious.
link |
00:26:58.580
And it could be that the future is,
link |
00:27:00.220
I mean, Siri is close, right?
link |
00:27:02.460
And so it might be the future
link |
00:27:04.540
has a lot more agents like that.
link |
00:27:07.100
And in fact, rather than someday going,
link |
00:27:08.860
aha, we have consciousness,
link |
00:27:10.700
we'll just creep up on it with more and more
link |
00:27:13.180
accurate reflections of what we expect.
link |
00:27:15.220
And in the future, maybe the present,
link |
00:27:18.320
for example, we haven't met before,
link |
00:27:20.800
and you're basically assuming that I'm human as it's a high
link |
00:27:25.300
probability at this time because the yeah,
link |
00:27:28.560
but in the future,
link |
00:27:30.200
there might be question marks around that, right?
link |
00:27:32.000
Yeah, no, absolutely.
link |
00:27:33.340
Certainly videos are almost to the point
link |
00:27:35.740
where you shouldn't trust them already.
link |
00:27:36.740
Photos you can't trust, right?
link |
00:27:39.060
Videos is easier to trust,
link |
00:27:41.700
but we're getting worse that,
link |
00:27:44.020
we're getting better at faking them, right?
link |
00:27:46.540
Yeah, so physical embodied people,
link |
00:27:48.780
what's so hard about faking that?
link |
00:27:51.020
So this is very depressing,
link |
00:27:51.980
this conversation we're having right now.
link |
00:27:53.420
So I mean,
link |
00:27:54.340
To me, it's exciting.
link |
00:27:55.180
To me, you're doing it.
link |
00:27:56.300
So it's exciting to you,
link |
00:27:57.780
but it's a sobering thought.
link |
00:27:59.060
We're very bad, right?
link |
00:28:00.420
At imagining what the next 50 years are gonna be like
link |
00:28:02.820
when we're in the middle of a phase transition
link |
00:28:04.220
as we are right now.
link |
00:28:05.260
Yeah, and I, in general,
link |
00:28:06.740
I'm not blind to all the threats.
link |
00:28:09.220
I am excited by the power of technology to solve,
link |
00:28:14.540
to protect us against the threats as they evolve.
link |
00:28:18.060
I'm not as much as Steven Pinker optimistic about the world,
link |
00:28:22.340
but in everything I've seen,
link |
00:28:23.740
all of the brilliant people in the world that I've met
link |
00:28:27.300
are good people.
link |
00:28:29.160
So the army of the good
link |
00:28:30.800
in terms of the development of technology is large.
link |
00:28:33.400
Okay, you're way more optimistic than I am.
link |
00:28:37.820
I think that goodness and badness
link |
00:28:39.060
are equally distributed among intelligent
link |
00:28:40.900
and unintelligent people.
link |
00:28:42.700
I don't see much of a correlation there.
link |
00:28:44.660
Interesting.
link |
00:28:46.060
Neither of us have proof.
link |
00:28:47.300
Yeah, exactly.
link |
00:28:48.420
Again, opinions are free, right?
link |
00:28:50.660
Nor definitions of good and evil.
link |
00:28:52.540
We come without definitions or without data opinions.
link |
00:28:57.460
So what kind of questions can science not currently answer
link |
00:29:01.980
and may never be able to answer in your view?
link |
00:29:04.380
Well, the obvious one is what is good and bad?
link |
00:29:06.940
What is right and wrong?
link |
00:29:07.860
I think that there are questions that,
link |
00:29:09.460
science tells us what happens,
link |
00:29:11.300
what the world is and what it does.
link |
00:29:13.260
It doesn't say what the world should do
link |
00:29:14.740
or what we should do,
link |
00:29:15.580
because we're part of the world.
link |
00:29:17.800
But we are part of the world
link |
00:29:19.200
and we have the ability to feel like something's right,
link |
00:29:21.460
something's wrong.
link |
00:29:22.740
And to make a very long story very short,
link |
00:29:25.660
I think that the idea of moral philosophy
link |
00:29:28.000
is systematizing our intuitions
link |
00:29:30.100
of what is right and what is wrong.
link |
00:29:31.700
And science might be able to predict ahead of time
link |
00:29:34.580
what we will do,
link |
00:29:36.180
but it won't ever be able to judge
link |
00:29:38.000
whether we should have done it or not.
link |
00:29:39.600
So, you're kind of unique in terms of scientists.
link |
00:29:43.620
Listen, it doesn't have to do with podcasts,
link |
00:29:45.520
but even just reaching out,
link |
00:29:47.660
I think you referred to as sort of
link |
00:29:49.080
doing interdisciplinary science.
link |
00:29:51.300
So you reach out and talk to people
link |
00:29:54.100
that are outside of your discipline,
link |
00:29:55.980
which I always hope that's what science was for.
link |
00:30:00.140
In fact, I was a little disillusioned
link |
00:30:02.300
when I realized that academia is very siloed.
link |
00:30:06.420
Yeah.
link |
00:30:07.260
And so the question is,
link |
00:30:10.700
how, at your own level,
link |
00:30:13.020
how do you prepare for these conversations?
link |
00:30:15.380
How do you think about these conversations?
link |
00:30:16.900
How do you open your mind enough
link |
00:30:18.300
to have these conversations?
link |
00:30:20.220
And it may be a little bit broader,
link |
00:30:21.940
how can you advise other scientists
link |
00:30:24.380
to have these kinds of conversations?
link |
00:30:26.260
Not at the podcast,
link |
00:30:28.180
the fact that you're doing a podcast is awesome,
link |
00:30:29.860
other people get to hear them,
link |
00:30:31.380
but it's also good to have it without mics in general.
link |
00:30:34.700
It's a good question, but a tough one to answer.
link |
00:30:37.460
I think about a guy I know who's a personal trainer,
link |
00:30:40.980
and he was asked on a podcast,
link |
00:30:43.240
how do we psych ourselves up to do a workout?
link |
00:30:45.700
How do we make that discipline to go and work out?
link |
00:30:48.340
And he's like, why are you asking me?
link |
00:30:50.300
I can't stop working out.
link |
00:30:52.340
I don't need to psych myself up.
link |
00:30:54.380
So, and likewise, he asked me,
link |
00:30:57.340
how do you get to have interdisciplinary conversations
link |
00:30:59.740
on all sorts of different things,
link |
00:31:00.700
all sorts of different people?
link |
00:31:01.660
I'm like, that's what makes me go, right?
link |
00:31:04.860
Like that's, I couldn't stop doing that.
link |
00:31:07.380
I did that long before any of them were recorded.
link |
00:31:09.660
In fact, a lot of the motivation for starting recording it
link |
00:31:12.380
was making sure I would read all these books
link |
00:31:14.420
that I had purchased, right?
link |
00:31:15.460
Like all these books I wanted to read,
link |
00:31:17.700
not enough time to read them.
link |
00:31:18.900
And now if I have the motivation,
link |
00:31:20.700
cause I'm gonna interview Pat Churchland,
link |
00:31:23.220
I'm gonna finally read her book.
link |
00:31:25.180
You know, and it's absolutely true
link |
00:31:29.460
that academia is extraordinarily siloed, right?
link |
00:31:31.700
We don't talk to people.
link |
00:31:32.780
We rarely do.
link |
00:31:34.260
And in fact, when we do, it's punished.
link |
00:31:36.460
You know, like the people who do it successfully
link |
00:31:38.820
generally first became very successful
link |
00:31:41.420
within their little siloed discipline.
link |
00:31:43.100
And only then did they start expanding out.
link |
00:31:46.380
If you're a young person, you know,
link |
00:31:47.660
I have graduate students.
link |
00:31:48.940
I try to be very, very candid with them about this,
link |
00:31:52.980
that it's, you know, most graduate students
link |
00:31:55.580
are to not become faculty members, right?
link |
00:31:57.420
It's a tough road.
link |
00:31:59.020
And so live the life you wanna live,
link |
00:32:03.140
but do it with your eyes open
link |
00:32:04.620
about what it does to your job chances.
link |
00:32:06.900
And the more broad you are
link |
00:32:09.580
and the less time you spend hyper specializing
link |
00:32:12.900
in your field, the lower your job chances are.
link |
00:32:15.780
That's just an academic reality.
link |
00:32:17.060
It's terrible, I don't like it, but it's a reality.
link |
00:32:20.060
And for some people, that's fine.
link |
00:32:22.540
Like there's plenty of people who are wonderful scientists
link |
00:32:24.660
who have zero interest in branching out
link |
00:32:27.140
and talking to things, to anyone outside their field.
link |
00:32:30.740
But it is disillusioning to me.
link |
00:32:33.740
Some of the, you know, romantic notion I had
link |
00:32:36.180
of the intellectual academic life
link |
00:32:38.220
is belied by the reality of it.
link |
00:32:39.940
The idea that we should reach out beyond our discipline
link |
00:32:43.500
and that is a positive good is just so rare
link |
00:32:48.500
in universities that it may as well not exist at all.
link |
00:32:53.900
But that said, even though you're saying you're doing it
link |
00:32:57.660
like the personal trainer, because you just can't help it,
link |
00:33:00.300
you're also an inspiration to others.
link |
00:33:02.940
Like I could speak for myself.
link |
00:33:05.780
You know, I also have a career I'm thinking about, right?
link |
00:33:09.540
And without your podcast,
link |
00:33:12.060
I may have not have been doing this at all, right?
link |
00:33:15.060
So it makes me realize that these kinds of conversations
link |
00:33:19.540
is kind of what science is about in many ways.
link |
00:33:23.340
The reason we write papers, this exchange of ideas,
link |
00:33:27.460
is it's much harder to do interdisciplinary papers,
link |
00:33:30.540
I would say.
link |
00:33:31.380
And conversations are easier.
link |
00:33:35.140
So conversations is the beginning.
link |
00:33:36.820
And in the field of AI, it's obvious
link |
00:33:41.180
that we should think outside of pure computer vision
link |
00:33:45.580
competitions on a particular data sets.
link |
00:33:47.540
We should think about the broader impact
link |
00:33:49.660
of how this can be, you know, reaching out to physics,
link |
00:33:53.740
to psychology, to neuroscience and having these
link |
00:33:57.220
conversations so that you're an inspiration.
link |
00:34:00.580
And so never know how the world changes.
link |
00:34:05.220
I mean, the fact that this stuff is out there
link |
00:34:08.540
and I've a huge number of people come up to me,
link |
00:34:12.300
grad students, really loving the podcast, inspired by it.
link |
00:34:16.100
And they will probably have that,
link |
00:34:18.660
they'll be ripple effects when they become faculty
link |
00:34:20.740
and so on and so on.
link |
00:34:21.580
We can end on a balance between pessimism and optimism.
link |
00:34:25.300
And Sean, thank you so much for talking to me, it was awesome.
link |
00:34:27.780
No, Lex, thank you very much for this conversation.
link |
00:34:29.460
It was great.