Sara Walker: Physics of Life, Time, Complexity, and Aliens | Lex Fridman Podcast #433
- So you have an original life event. It evolves for 4 billion
years, at least on our planet. It evolves a technosphere. The technologies themselves start having this property we call life, which is the phase we're undergoing now. It solves the origin of itself, and then it figures out
how that process all works, understands how to make more life and then can copy itself
onto another planet, so the whole structure
can reproduce itself. - The following is a
conversation with Sara Walker, her third time in this podcast. She is an astrobiologist
and theoretical physicist, interested in the origin of life and in discovering alien
life on other worlds. She has written an amazing
new upcoming book titled, "Life as No One Knows It: The
Physics of Life's Emergence." This book is coming out on August 6th, so please go pre-order it now. It will blow your mind. This is a Lex Fridman podcast, to support it, please check out our
sponsors in the description. And now, dear friends, here's Sara Walker. You open the book, "Life
as No One Knows It: The Physics of Life's Emergence," with the distinction
between the materialists and the vitalists. So what's the difference?
Can you maybe define the two? - I think the question there is about whether life can be
described in terms of matter and you know, physical things, or whether there is some other feature, that's not physical, that
actually animates living things. So for a long time people
maybe have called that a soul. It's been really hard to
pin down what that is. So I think the vitalist
idea is really that, it's kind of a dualistic interpretation, that there's sort of
the material properties, but there's something
else that animates life that is there when you're alive and it's not there when you're dead. And materialists kind of don't think that there's anything really special about the matter of life and the material substrates
that life is made out of. So they disagree on some
really fundamental points. - Is there a gray area between the two? Like maybe all there is is matter, but there's so much we don't know that it might as well be magic? (Sara laughs) That like whatever that
magic that the vitalists see. Meaning like-
- Yeah. - There's just so much mystery that it's really unfair
to say that it's boring and understood, and as simple
as quote unquote "physics." - Yeah, I think the entire
universe is just a giant mystery. I guess that's what
motivates me as a scientist. And so oftentimes when
I look at open problems like the nature of life or consciousness, or you know, what is intelligence? Or are there souls? Or whatever question that we have, that we feel like we aren't even on the tip of answering yet. I think, you know, we
have a lot more work to do to really understand the
answers to these questions. So it's not magic, it's just the unknown. And I think a lot of the history of humans coming to understand the world around us has been taking ideas that
we once thought were magic or supernatural, and really understanding
them in a much deeper way, that we learn what those things are, and they still have an air of mystery even when we understand them. There's no sort of bottom
to our understanding. - So do you think the
vitalists have a point, that they're more eager and able to notice the magic of life? - I think that no tradition,
vitalists included, is ever fully wrong about the nature of the things
that they're describing. So a lot of times when
I look at different ways that people have described
things across human history, across different cultures, there's always a seed of truth in them, and I think it's really important
to try to look for those, because if there are narratives that humans have been telling ourselves for thousands of years, for
thousands of generations, there must be some truth to them. You know, we've been
learning about reality for a really long time, and we recognize the patterns
that reality presents us, we don't always understand
what those patterns are. And so I think it's really important to pay attention to that. So I don't think the
vitalists were actually wrong, and a lot of what I
talk about in the book, but also I think about a
lot just professionally, is the nature of our
definitions of what's material, and how science has come to
invent the concept of matter. And that some of those things
actually really are inventions that happened in a particular time, in a particular technology that could learn about certain patterns and help us understand them, and that there are some patterns
we still don't understand. And if we knew how to measure those things or we knew how to describe
them in a more rigorous way, we would realize that the
material world, matter, has more properties than
we thought that it did. And one of those might be associated with the thing that we call life. Life could be a material property and still have a lot of the features that the vitalists
thought were mysterious. - So we may still expand our understanding what is incorporated in
the category of matter that will eventually
incorporate such magical things that the vitalists have noticed- - Yeah-
- Like life. - Yeah, so I think about... I always like to use
examples from physics, so I'll probably do that to, (laughs) Like it's my go-to place. But you know, in the history
of gravitational physics, for example, in the history of motion, you know like when Aristotle came up with his theories of motion, he did it by the material
properties he thought things had. So there was a concept of
things falling to Earth because they were solid-like, and things raising to the
heavens 'cause they were airlike, and things moving around the planet 'cause they were celestial-like. But then we came to realize
that thousands of years later and after the invention
of many technologies that allowed us to actually measure time in a mechanistic way and
track planetary motion, and we could, you know, roll
balls down inclined planes and track that progress. We realized that if we
just talked about mass and acceleration, we could
unify all motion in the universe in a really simple description. So we didn't really have
to worry about the fact that my cup is heavy and the air is light, like the same laws describe them, if we have the right material
properties to talk about what those laws are
actually interacting with. And so I think the issue with life is, we don't know how to
think about information in a material way. And so we haven't been able
to build a unified description of what life is or the kind of things
that evolution builds, because we haven't really invented the right material concept yet. - So when talking about motion, the laws of physics appear to be the same everywhere out in the universe. You think the same is true
for other kinds of matter that we might eventually include life in? - I think life obeys universal principles. I think there is some deep
underlying exploratory framework that will tell us about the
nature of life in the universe and will allow us to identify life that we can't yet recognize
because it's too different. - You write about the
paradox of defining life. Why does this seem to be so easy and so complicated at the same time? - You know, all the sort
of classic definitions people want to use just don't work. They don't work in all cases. So Carl Sagan had this wonderful essay on definitions of life, where I think he talks about aliens coming from another planet, If they saw Earth, they might think that cars
were the dominant life form because there's so many
of them on our planet, and like humans are inside them, and you might wanna exclude machines, but any definition, you know, like classic biology textbook definitions would also include them. And so, you know, he
wanted to draw a boundary between these kind of things
by trying to exclude them, but they were naturally included by the definitions people wanna give. And in fact, what he ended up pointing out is that all of the definitions
of life that we have, whether it's, life is a
self reproducing system, or life eats to survive, or life requires
compartments, whatever it is, there's always a counter example that challenges that definition. This is why viruses are so
hard or why fire is so hard. And so we've had a really hard time trying to pin down, from a
definitional perspective, exactly what life is. - Yeah, you actually bring
up the zombie-ant fungus. I enjoyed looking at this thing, (Sara laughs)
as an example of one of the challenges. You mentioned viruses,
but this is a parasite. Look at that. - Did you see this in jungle?
- In fact, ants... Actually one of the interesting
things about the jungle, that everything is ephemeral. Like everything eats
everything really quickly. So if an organism dies,
that organism disappears. - Yeah.
- It's a machine that doesn't have... I wanted to say it doesn't
have a memory or a history, which is interesting
given your work on history in defining a living being. The jungle forgets very quickly. It wants to erase the fact
that you existed very quickly. - Yeah, but it can't erase it,
it's just restructuring it. And I think the other thing
that is really, you know, vivid to me about this
example that you're giving is, how much death is necessary for life. So I worry a bit about
notions of immortality and whether immortality
is a good thing or not. So I have sort of a broad conception that life is the only thing
the universe generates that actually has even the
potential to be immortal. But that's as like the sort of process that you're describing, where life is about memory
and historical contingency, and construction of new possibilities. But when you look at any instance of life, especially one as dynamic
as what you're describing, it's a constant birth and death process. But that birth and death process is like, the way that the universe can explore what possibilities can exist, and not everything, not
every possible human or every possible ant or
every possible zombie ant or every possible tree will ever live. So it's, you know, it's
an incredibly dynamic and creative place
because of all that death. - So does this thing... This is a parasite that needs the ant. So is this a living thing or is this not a living thing? So this is- - Yeah, so-
- It just pierces the ant. I mean it-
- Right. - And I've seen a lot of this by the way, organisms working together in the jungle, like ants protecting a
delicious piece of fruit. So they need the fruit. But like if you touch that fruit, they're going to like... The forces emerge. - Yeah.
- They're fighting you, they're defending that fruit. - Right.
- To the death. Nature seems to find
mutual benefits, right? - Yeah, it does. I think the thing that's perplexing for me about these kind of examples is, you know, effectively the ant's dead
but it's staying alive now 'cause it's piloted by this fungus. And so that gets back to this, you know, thing that we're talking
about a few minutes ago about how the boundary of
life is really hard to define. So you know, anytime that
you wanna draw a boundary around something and you say, "This feature is the thing
that makes this alive," or "This thing is alive on its own," there's not ever really a clear boundary, and these kind of examples are
really good at showing that, because it's like the thing
that you would've thought is the living organism is now dead, except that it has another living organism that's piloting it. So the two of them together
are alive in some sense, but they're, you know, now in this kind of weird
symbiotic relationship that's taking this ant to its death. - So what do you do with that in terms of when you try to define life? - I think we have to get rid of the notion of an individual as being relevant. And this is really difficult because you know, a lot of the ways that we think about life, like the fundamental
unit of life is the cell, individuals are alive, but we don't think about how
gray that distinction is. So for example, you might consider, you know, self reproduction to be the most defining feature
of life, a lot of people do. Actually like it's, you know, one of these standard
different definitions that a lot of people
in my field like to use in astrobiology is, life is a self-sustaining chemical system capable of Darwinian evolution. Which I was once quoted as agreeing with, and I was really offended,
because I hate that definition. I think it's terrible, and I think it's terrible
that people use it. I think like every word in that definition is actually wrong as a descriptor of life. - Life is a self-sustaining
chemical system capable of Darwinian evolution. Why is that... That seems like a pretty good definition. - Yeah, I know. If you wanna make me angry
you can pretend I said that, (Sara laughs) and believed it. - So self-sustaining chemical system, Darwinian evolution. What is self-sustaining?
What's so frustrating? I mean which aspect is frustrating to you, but it's also, those are
very interesting words. - Yeah, they're all interesting words and you know, together
they sound really smart and they sound like they
box in what life is. But you can use any of
the words individually and you can come up with counter examples that don't fulfill that property. The self-sustaining one
is really interesting, thinking about humans, right? Like we're not self-sustaining, we're dependent on societies. And so, you know, I find
it paradoxical that, you know, it might be that societies, because they are self-sustaining units, are now more alive than individuals are. And that could be the case. But I still think we have some property associated with life. I mean that's the thing that
we're trying to describe. So that one's quite hard. And in general, you know, no organism is really self-sustaining. They always require an environment. So being self-sustaining
is coupled, in some sense, to the world around you. We don't live in a vacuum, so that part's already challenging, and then you can go to chemical system. I don't think that's good either. I think there's a confusion because life emerges in
chemistry, that life is chemical. I don't think life is chemical. I think life emerges in chemistry because chemistry is the first
thing the universe builds where it cannot exhaust
all the possibilities, because the combinatorial space
of chemistry is too large. - Well but is it possible to have a life that is not a chemical system? - Yes. - Well, there's a guy I
know named Lee Cronin, he's been on the podcast a couple times. He just got really pissed off-
- I know that guy too- - Listening to this. (laughs)
- What a coincidence. He probably just got really
pissed off hearing that. For people who somehow
don't know, he's a chemist. - Yeah, but he would
agree with that statement. - Would he? I don't think he would. I don't think he would. He would broaden the
definition of chemistry until it'll include everything. - Oh sure.
- Okay, so you're- - Or maybe, I don't know,
- But wait, but you said that universe, the first thing it creates is chemistry. - Very precisely, it's not the first thing it creates, obviously like, it has
to make atoms first, but it's the first thing, like if you think about, you know, the universe originated, atoms were made in, you know,
Big Bang nucleosynthesis, and then later in stars,
and then planets formed, and planets become engines of chemistry. They start exploring what
kind of chemistry is possible. And the combinatorial space
of chemistry is so large that even on every planet
in the entire universe, you will never express
every possible molecule. I like this example
actually that Lee gave me, which is to think about Taxol, it has a molecular weight of about 853. It's got, you know, a lot of atoms but it's not astronomically large. And if you try to make one molecule with that molecular formula in every three dimensional
shape you could make with that molecular formula, it would fill 1.5 universes in volume. So with one unique molecule,
that's just one molecule. So chemical space is huge, and I think it's really
important to recognize that, because if you wanna ask a question of, why does life emerge in chemistry? Well life emerges in chemistry because life is the physics
of how the universe selects what gets to exist. And those things get created along historically contingent
pathways and memory and all the other stuff
that we can talk about. But the universe has to actually make historically contingent
choices in chemistry, 'cause it can't exhaust
all possible molecules. - What kind of things can you create that's outside the combinatorial
space of chemistry? That's what I'm trying to understand- - Oh, if it's not chemical. So I think some of the things that have evolved on our biosphere, I would call as much alive
as chemistry, as a cell, but they seem much more abstract. So for example, I think language is alive. I think, or at least life. I think memes are. I think-
- You're saying language is life? - Yes.
- Language is alive. Oh boy, I'm gonna have
to explore that one. (Sara laughs) Okay, but-
- Life, maybe not alive, but I don't... Actually, I don't know where
I stand exactly on that. I've been thinking about that
a little bit more lately. But mathematics too, and it's interesting, 'cause people think that math
has this platonic reality that exists outside of our universe. And I think it's a
feature of our biosphere, and it's telling us something about the structure of ourselves. And I find that really interesting, 'cause when you would sort of internalize all of these things that
we noticed about the world and you start asking, "Well,
what do these look like if I was, you know,
something outside of myself, observing these systems
that all embedded in, what would that structure look like?" And I think we look really different than the way that we talk about what we look like to each other. - What do you think a
living organism in math is? Is it one axiomatic system or is it individual theorems or is it- - I think it's the fact that
it's open-ended in some sense. It's another open-ended
combinatorial space. And the recursive properties of it allow creativity to happen. Which is what you see with, you know, like the revolution in the last century with Godel's theorem
and Turing and you know, there's clear places where mathematics notices
holes in the universe. - So it seems like you're sneaking up on a different kind of definition of life. Open-ended, large combinatorial space. - Yeah.
- Room for creativity. - Definitely not chemical. I mean chemistry is one substrate.
- Restrict to chemical. - Yeah.
- Chemical. Okay, what about the third thing, which I think would be the hardest, 'cause you probably like
it the most, is evolution or selection. - Well, specifically
it's Darwinian evolution. - Darwinian, okay.
- And I think Darwinian evolution is a problem. But the reason that that
definition is a problem is not because evolution
is in the definition, but because the implication
is that, you know, that most people would wanna make is that an individual is alive. And the evolutionary process, at least the Darwinian
evolutionary process and most evolutionary processes, they don't happen at the
level of individuals, they happen at the level of population. So again, you would be saying something, like what we saw with the
self-sustaining definition, which is that populations are alive, but individuals aren't, because populations evolve
and individuals don't. And obviously like maybe you are alive because you know, your gut
microbiome is evolving. But Lex as an entity
right now is not evolving by canonical theories of evolution. In assembly theory, which is attempting to explain life, evolution is a much broader thing, so- - So an individual organism can evolve under assembly theory. - Yes, you're constructing
yourself all the time. Assembly theory is about construction and how the universe
selects for things to exist. - What if you reformulate everything? Like a population is
a living organism, so- - That's fine too.
- Right. - But this again gets back to... So I think what all of the... You know, like we can
nitpick at definitions. I don't think it's like
incredibly helpful to do it. But the reason for me-
- It's fun. - Yeah, it is fun. It is really fun. And actually I do think it's useful, in the sense that when you see the ways that they all break down, you either have to keep forcing in, your like sort of conception
of life you want to have, or you have to say, "All these definitions are
breaking down for a reason. Maybe I should adopt a
more expansive definition that encompasses all the things
that I think and our life." And so for me, I think life is the process of how information structures
matter over time and space, and an example of life is
what emerges on a planet and yields an open-ended cascade
of generation of structure and increasing complexity, and this is the thing that life is. And any individual is
just a particular instance of these lineages that are, you know, structured across time. And so we focus so much
on these individuals that are these short temporal moments in this larger causal structure that actually is the life on our planet. And I think that's why these
definitions break down, because they're not general enough, they're not universal enough,
they're not deep enough, they're not abstract enough to actually capture that regularity. - Because we're focused on
that little ephemeral thing. - Yeah, it's like-
- That we call human life? - Aristotle focusing on, you know, heavy things falling
because they're earth-like, and you know, things floating
'cause they're airlike, it's the wrong thing to focus on. - So what exactly are we missing by focusing on such a short span of time? - I think we're missing
most of what we are. So one of the issues, I've been thinking about this like really viscerally lately, it's weird when you do
theoretical physics, because I think it like literally changes the structure of your brain, (laughs) and you see the world differently, especially when you're trying
to build new abstractions. - Do you think it's possible, if you're a theoretical physicist, that like it's easy to fall off the cliff and go descend into madness? - I mean I think you're
always on the edge of it, but I think what is amazing
about being a scientist and trying to do things rigorously,
is it keeps your sanity. So I think if I wasn't
a theoretical physicist, I would be probably not sane, but what it forces you
to do is hold the... Like you have to hold
yourself to the fire of like, these abstractions in my mind have to really correspond to reality, and I have to really
test that all the time. And so I love building new abstractions and I love going to those
like incredibly creative, you know, spaces that people don't see as part of the way that we
understand the world now. But ultimately, I have to make sure that whatever I'm pulling from that space is something that's really usable and really like relates to
the world outside of me. That's what science is. - So we were talking about what we're missing when we
look at a small stretch of time in a small stretch of space. - Yeah. So the issue is, we evolve perception to see reality a certain way, right? So for us, space is really important and time feels fleeting and I, you know, I had a really wonderful
mentor, Paul Davies, most of my career. And Paul's amazing because
he gives these like little seed thought
experiments all the time. Like, you know, something
he used to ask me all the time when I was a postdoc, this is kind of a random tangent, but was like, you know,
how much of the universe could be converted into technology? If you were thinking about like, you know, long-term futures and stuff like that. And it's like a weird thought experiment but like, there's a lot
of deep things there. But I do think a lot about the fact that, we're really limited in our
interactions with reality by the particular
architectures that we evolved, and so we're not seeing everything. And in fact our technology
tells us this all the time because it allows us to
see the world in new ways by basically allowing
us to perceive the world in ways that we couldn't otherwise. And so what I'm getting at with this is, I think that living
objects are actually huge. Like there're some of
the biggest structures in the universe, but they
are not big in space, they're big in time. And we actually can't
resolve that feature. We don't interact with
it on a regular basis. So we see them as these fleeting things that have this really
short temporal clock time without seeing how large they are. When I'm saying time here, I really like the way that
people could picture it is in terms of causal structure. So if you think about the
history of the universe to get to you, and you imagine that that
entire history is you, that is the picture I have in my mind when I look at every living thing. - So you have a tweet for everything. (Sara laughs)
You tweeted- - Doesn't everyone? - You have a lot of
poetic, profound tweets. Sometimes-
- Thank you. - They're puzzles that take
a long time to figure out. - Well you know what the trick is, the reason they're hard to write is because it's compressing
a very deep idea into a short amount of space, and I really like doing
that intellectual exercise, 'cause I find it productive for me. - Yeah, it's a very
interesting kind of compression algorithm though. - Yeah, I like language. I think it's really fun to play with. - Yeah, I wonder if AI can decompress it. That'd be interesting- - I would like to try this, but I think I use language in certain ways that are non-canonical, and
I do it very purposefully, and it would be interesting to
me how AI would interpret it. - Yeah, your tweets would
be a good Turing test. - There you go.
- For a super intelligence. Anyway, you tweeted that,
"Things only look emergent because we can't see time. So if we could see time, what
would the world look like?" You're saying you would
be able to see everything that an object has been, every step of the way that
led to this current moment, and all the interactions that are required to make that evolution happen. You would see this gigantic tale. - The universe is far larger
in time than it is in space. - Yeah.
- And this planet is one of the biggest
things in the universe. - Oh, so the more complexity, the bigger- - Yeah, so like the technosphere, I think the modern technosphere is the largest object in time in the universe that we know about. - And when you say
technosphere, what do you mean? - I mean the global integration of life and technology on this planet. - So all the things, all the technological
things we've created? - Mm-hmm, but I don't
think of them as separate. They're like very integrated with the structure that generated them. So you can almost imagine it, like time is constantly bifurcating, and it's generating new structures, and these new structures are, you know, locally constructing the future. And so things like you and I are very close together in time, 'cause we didn't diverge like very early in the history of
universe, it's very recent. And I think this is one of the reasons that we can understand each other so well and we can communicate effectively. And I might have some sense of
what it feels like to be you, but you know, other
organisms bifurcated from us in time earlier, this is just the concept
of phylogeny, right? But if you take that deeper and you really think about that as the structure of the
physics that generates life, and you take that very seriously, all of that causation is still bundled up in the objects we observe today. And so you and I are are close
in this temporal structure, but we're also... And we're so close
because we're really big, and we only are very different in sort of like the most
recent moments in the time that's like embedded in us. It's hard to use words to visualize what's in minds. (laughs) I have such a hard time
with this sometimes. I'm like, I like... I actually was thinking
on the way over here, I was like, you know, you
have pictures in your brain and then they're hard to put into words, but I realized I always
say I have a visual, but it's not actually I have a visual. It's, I have a feeling, 'cause oftentimes I cannot
actually draw a picture in my mind for the things that I say, but sometimes they go through a picture before they get to words, but I like experimenting with words because I think they help paint pictures. - Yeah, it's again, some
kind of compressed feeling that you can query to get a sense of the bigger visualization that you have in mind. - Yeah.
- It's just like a really nice compression. But I think the idea of this object that in it contains all the
information about the history of an entity that you see now, just trying to visualize
that is pretty cool. - Yeah.
- I mean obviously the mind breaks down
quickly as you step seconds and minutes back in time.
- Yeah, for sure - I guess it's just a gigantic object- - Yeah.
- What you're supposed to be thinking about. - Yeah, I think so, and I think this is one of the reasons that we have such an ability
to abstract as humans, because we are so gigantic, that like the space
that we can go back into is really large. So like the more abstract you're going, like the deeper you're
going in that space. - But in that sense, aren't we
fundamentally all connected? - Yes, and this is why
the definition of life cannot be the individual, it has to be these lineages, because they're all
connected, they're interwoven, and they're exchanging parts all the time. - Yeah, so maybe there's certain
aspects of those lineages that can be lifelike, they
can be characteristics, they can be measured like with
assembly theory that have- - Yeah.
- More or less life, but they're all just fingertips of a- - Yeah.
- Of a much bigger object. - Yeah, I think life is
very high dimensional. And in fact I think you can
be alive in some dimensions and not in others. Like if you could
project all the causation that's in you in some
features of you, you know, very little causation is required,
like very little history, and in some features a lot is. So it's quite difficult to take this really high
dimensional, very deep structure, and project it into things
that we really can understand and say like, "This is the
one thing that we're seeing," because it's not one thing. - It's funny, we're talking about this now and I'm slowly starting to realize, one of the things I saw
when I took ayahuasca, afterwards actually, so the actual ceremony
is four or five hours, but afterwards you're still riding whatever the thing that you're riding. And I got a chance to, afterwards, hang out with some friends and just shoot the shit in
the, you know, in the forest. And I get to see their faces. And what was happening with their faces and their hair is, I would
get this interesting effect. First of all, everything was beautiful and I just had so much love for everybody. But I could see their past
selves like behind them. It was this effect where... I guess it's a blurring effect? Of where like if I move like this, the faces that were just
there are still there and it would just float like this, behind them, which will
create this incredible effect. But it's also another way
to think about that is, I'm visualizing a little
bit of that object, of the thing they were
just a few seconds ago. - Yeah.
- It's a cool little effect. - That's very cool. - And now it's like giving
it a bit more profundity to the effect that was just
beautiful aesthetically, but it's also beautiful
from a physics perspective, because that is a past self. I get a little glimpse at the past selves that they were, but then you take that to its natural conclusion,
not just a few seconds ago, but just to the beginning of the universe, and you can probably get to that-
- Yeah, billions of years, yeah.
- Get down that lineage. - It's crazy that
there's billions of years inside all of us. - All of us.
- Yeah. - And then we connect obviously. - Yeah.
- Not too long ago. - Yeah. - You mentioned just the technosphere and you also wrote that, "The most alive thing on this planet is our technosphere." - Yeah.
- Why is the technology we create a kind of life form? Why are you seeing it as life? - Because it's creative, but with us obviously, like
not independently of us, and also because of this
sort of lineage view of life, and I think about life often as a planetary scale phenomena, 'cause that's sort of the natural boundary for all of this causation that's bundled in every object in our biosphere. And so for me, it's just
sort of the current boundary of how far life on our planet has pushed into the things that our
universe can generate. And so it's the furthest
thing, it's the biggest thing. And I think a lot about the nature of life across different scales. And so, you know, we have cells
inside of us that are alive and we feel like we're alive, but we don't often think
about the societies that we're embedded in as alive or a global scale organization of us and our technology on the planet as alive. But I think if you have this deeper view into the nature of life, which I think is necessary also
to solve the origin of life, then you have to include those things. - All of them. So you have to simultaneously think about- - Every scale
- Life at every single scale. - Yeah.
- The planetary and the bacteria level. - Yeah, this is the hard thing about solving the problem of life, I think, is how many things you have to integrate into building a sort of a unified picture of this thing that we wanna call life, and a lot of our theories of physics are built on building deep regularities that explain a really
broad class of phenomenon. And I think we haven't
really traditionally thought about life that
way, but I think to get at some of these hardest questions, like looking for life on other planets or the origin of life, you really have to
think about it that way. And so most of like my professional work is just trying to understand
like every single thing on this planet that might
be an example of life, which is pretty much everything, and then trying to figure out like, what's the deeper
structure underlying that. - Yeah, Schrodinger wrote that, "Living matter, while not
eluding the laws of physics as established up to date, is likely to involve other laws of physics hitherto unknown." So to him- - I love that quote. - There was a sense that, at the bottom of this
are new laws of physics that could explain this
thing that we call life. - Yeah, Schrodinger really tried to do what physicists try to do, which is explain things, and his attempt was to try to explain life in terms of non-equilibrium physics, because he thought that
was the best description that we could generate at the time. And so he did come up with
something really insightful, which was to predict the structure of DNA as an aperiodic crystal. And that was for a very
precise reason that, you know, that was the only kind
of physical structure that could encode enough information to actually specify a cell. We knew some things about
genes, but not about DNA and its actual structure
when he proposed that. But in the book he tried to explain, life is kind of going against entropy. And so some people talked about it as like Schrodinger's paradox, how can life persist when the second law of
thermodynamics is there? But in open systems
that's not so problematic. And really, the question is, why can life generate so much order? And we don't have a
physics to describe that. And it's interesting, you know, generations of physicists have
thought about this problem. Oftentimes it's like
when people are retiring, they're like, "Oh, now
I can work on life." Or they're like more
senior in their career and they worked on other
more traditional problems. And there's still a lot of
impetus in the physics community to think that non-equilibrium
physics will explain life, but I think that's not the right approach. I don't think ultimately the solution to what life is is there, and I don't really think
entropy has much to do with it unless it's entirely reformulated. - Well, because you have to
explain how interesting order, how complexity emerges from the soup. - Yes, from randomness. - From randomness. Physics currently can't do that. - No, Physics hardly even acknowledges that the universe is random
at its base. (laughs) We like to think we live
in a deterministic universe and everything's deterministic. But I think that's probably, you know, an artifact of the way
that we've written down laws of physics since Newton
invented modern physics and his conception of motion
and gravity, which, you know, he formulated laws that
had initial conditions and fixed dynamical laws, and that's sort of
become the standard canon of how people think the universe works and how we need to describe
any physical system, is with an initial condition
and a law of motion. And I think that's not actually the way the universe really works. I think it's a good approximation
for the kind of systems that physicists have studied so far. And I think it will radically fail in the long term at describing reality at its more basal levels, but I'm not saying there's a base, I don't think that reality has a ground and I don't think there's
a theory of everything, but I think there are better theories, and I think there are
more explanatory theories, and I think we can get to something that explains much more than
the current laws of physics do. - When you say theory of everything, you mean like everything, everything. - Yeah, you know, like
in physics right now, it's really popular to talk
about theories of everything. So string theory is supposed
to be a theory of everything because it unifies quantum
mechanics and gravity, and you know, people have their different
pet theories of everything, and the challenge with
a theory of everything, I really love this quote
quote from David Krakauer, which is, "A theory of everything is a theory of everything except those things that theorize." - Oh, you mean removing the
observer from the thing? - Yeah, but it's also weird because if a theory of
everything explained everything, it should also explain the theory. So the theory has to be recursive, and none of our theories
of physics are recursive. So it's a weird concept. - Yeah, but it's very difficult to integrate the observer into a theory. - I don't think so. I think you can build
a theory acknowledging that you're an observer
inside the universe, - But doesn't it become
recursive in that way? And you're saying it's
possible to make a theory that's okay with that? - I think so. I mean, I don't think... There's always gonna be the paradox of another meta level you could build on the meta level, right? So like if you assume
this is your universe and you're the observer outside of it, you have some meta
description of that universe, but then you need a meta description of you describing that universe, right? So, you know, this is one
of the biggest challenges that we face being observers
inside our universe. And also, you know, why the paradoxes and the foundations of mathematics and any place that we try to
have observers in the system or a system describing itself show up. But I think it is possible
to build a physics that builds in those things intrinsically, without having them be paradoxical or have holes in the descriptions. And so one place I think
about this quite a lot, which I think can give you sort
of a more concrete example, is the nature of like
what we call fundamental. So we typically define
fundamental right now in terms of the smallest
indivisible units of matter. So again, you have to have a definition of what you think material
is, and matter is, but right now the, you know, what's fundamental are
elementary particles, and we think they're fundamental, because we can't break them apart further, and obviously we have
theories like string theory that if they're right, would
replace the current description of what's the most fundamental
thing in our universe by replacing it with something smaller, but we can't get to those theories, because we're technologically limited. And so if you look at this
from a historical perspective and you think about explanations changing as physical systems like us learn more about the
reality in which they live, we once considered atoms to
be the most fundamental thing. And you know, it literally
comes from the word indivisible. And then we realized
atoms had substructure because we built better technology, which allowed us to quote
unquote, "see the world better," and resolve smaller features of it. And then we built even better technology, which allowed us to see
even smaller structure and get down to the
standard model particles. And we think that there might
be structure below that, but we can't get there
yet with our technology. So what's fundamental, the way we talk about
it in current physics is not actually fundamental. It's the boundaries of what we
can observe in our universe, what we can see with our technology. And so if you wanna build
a theory that's about us and about what's inside the universe that we can observe, not
what's at the boundary of it, you need to talk about objects
that are in the universe, that you can actually break
apart to smaller things. So I think the things that are fundamental are actually the constructed objects. They're the ones that really exist and you really understand
their properties, because you know how the
universe constructed them, because you can actually take them apart. You can understand the
intrinsic laws that built them, but the things at the boundary
are just at the boundary, they're evolving with us, and we'll learn more about
that structure as we go along. But really, if we wanna talk
about what's fundamental inside our universe, we have to talk about all these things that are traditionally
considered emergent, but are really just structures in time that have causal histories
that constructed them, and you know, are really actually what our universe is about. - So we should focus on the construction methodology
as the fundamental thing. But do you think there's a bottom to the smallest possible thing
that makes up the universe? - I don't see one. - And it'll take way too long. It'll take longer to find that, than it will to understand the
mechanism that created life. - I think so, yeah. I think for me, the
frontier in modern physics, where the new physics lies, is not in high energy particle physics, it's not in quantum gravity, it's not in any of these
sort of traditionally sold, "This is gonna be the
newest, deepest insight we have into the nature of reality." It is going to be in studying
the problems of life, and intelligence, and the
things that are sort of also our current existential
crises as a civilization or a culture that's
going through, you know, an existential trauma of
inventing technologies that we don't understand right now. - The existential trauma, and the terror we feel
that that technology might somehow destroy us, us meaning living,
intelligent living organisms- - Right.
- And yet we don't understand what that even means. - Well, humans have always been afraid of our technologies though, right? So it's kind of a fascinating thing that every time we invent
something we don't understand, it takes us a little
while to catch up with it. - I think also in part, humans
kind of love being afraid. - Yeah, we love being traumatized. - It's weird, the drama.
- We wanna learn more, and then when we learn more
it traumatizes us. (laughs) (Lex laughs) You know, I never thought
about this before, but I think this is one of
the reasons I love what I do is because it traumatizes
me all the time. (laughs) That sounds really bad, but what I mean is like, I love
the shock of like realizing that like coming to understand something in a way that you never
understood it before. I think it seems to me, when I see a lot of the ways other people react to new ideas, that they don't feel
that way intrinsically. But for me that's like... That's why I do what I do. I love that feeling. - But you're also working on a topic where it's fundamentally ego destroying, because you're talking about like life. It's humbling to think that we're not... The individual human is not special. - Yeah.
- And you're like very viscerally exploring that. - Yeah, I'm trying to embody that. I think you have to live the
physics to understand it. But there's a great quote about Einstein, I don't know if this is true or not, that he once said that
he could feel light beam in his belly. And I think...
(both chuckle) But I think like, you gotta
think about it though, right? Like if you're a really deep thinker, and you're really thinking
about reality that deeply, and you are part of the reality that you're trying to describe, like you feel it, you really feel it. - That's what I was saying about, you're always like
walking along the cliff, and if you fall off, you're
falling into madness. - Yes, it's a constant,
constant descent into madness. - The fascinating thing about physicists and madness is that you don't know if you've fallen off the cliff. - Yeah, I know. You don't know. - That's the cool thing about that.
- I rely on other people to tell me. Actually this is very funny, 'cause like I have these conversations with my students often, like they're worried about
going crazy, (laughs) and I have to like reassure them that like one of the
reasons they'll stay sane is by trying to work on concrete problems. - Going crazy or waking up? I don't know which one it is.
- Yeah. - So what do you think is
the origin of life on Earth, and how can we talk about
it in a productive way? - The origin of life is like this boundary that the universe can only cross if a structure that emerges can
reinforce its own existence, which is self reproduction,
auto catalysis, things people traditionally talk about. But it has to be able to maintain its own existence against this sort of randomness
that happens in chemistry, and this randomness that
happens in the quantum world. And like it's in some sense, the emergence of like a
deterministic structure that says, you know, "I'm gonna exist and
I'm gonna keep going." But you know, pinning
that down is really hard. We have ways of thinking
about it in assembly theory that I think are pretty rigorous, and one of the things
I'm really excited about is trying to actually quantify in an assembly theoretic way when the origin of life happens. But the basic process I have in mind is like a system that has no causal contingency,
no constraints of objects, basically constraining the
existence of other objects or allowing the existence
of other objects. And so that sounds very abstract, but like you can just think
of like a chemical reaction can't happen if there's not
a catalyst, for example. Or a baby can't be born
if there wasn't a parent. So there's a lot of causal contingency that's necessary for
certain things to happen. So you think about this sort
of unconstrained random system, there's nothing that reinforces the existence of other things. So the sort of resources
just get washed out in all of these different structures, and none of them exist again. Or they just, you know... They're not very complicated
if they're in high abundance, and some random events allow some things to start reinforcing the existence of a small subset of objects. And if they can do that, you know, like just molecules basically
recognizing each other and being able to catalyze
certain reactions. There's this kind of
transition point that happens, where unless you get a
self-reinforcing structure, something that can
maintain its own existence, it actually can't cross this boundary to make any objects in high abundance without having this sort of past history that it's carrying with us, and maintaining the existence
of that past history, and that boundary point
where objects can't exist unless they have the
selection and history in them, is what we call the origin of life. And pretty much everything
beyond that boundary, is holding on for dear life
to all of the causation and causal structure that's
basically put it there, and it's carving its way
through this possibility space into generating more and more structure, and that's when you get the
open-ended cascade of evolution. But that boundary point
is really hard to cross, and then what happens when
you cross that boundary point and the way objects come into existence is also like really fascinating dynamics, because you know, like as
things become more complex, the assembly index increases. I can explain all these things, sorry. You can tell me what you want explained. (Sara laughs) Or what people will wanna hear. Sorry, I have like a very
vivid visual in my brain and it's really hard to articulate it. - Gotta convert it to language. - I know, it's so hard.
(Sara laughs) It's like, it's going from like a feeling, to a visual, to language,
is so stifling sometimes. - And then I have to convert it- - Yeah.
- From language to a visual. - Yeah.
- To a feeling. - Yeah.
- I think it's working. - I hope so.
- I really like the self-reinforcing objects. I mean, just so-
- Yeah. - Just so I understand, one way to create a lot
of the same kind of object is make them self reinforcing. - Yes, so self reproduction
has its property, right? Like if that system can make itself, then it can persist in time, right? Because all objects decay, they
all have a finite lifetime. So if you're able to make a
copy of yourself before you die, before the second law eats you or whatever people think happens, then that structure can persist in time. - So that's a way to sort of
emerge out of a random soup. Outta the randomness of soup.
- Yes. Right, but things that can
copy themselves are very rare. - Yeah.
- And so what ends up happening is that you get structures that enable the existence of other things, and then somehow, only
for some sets of objects, you get closed structures
that are self-reinforcing, and allow that entire
structure to persist. - Right, so the one... Object A reinforces the
existence of object B, but you know, object A can die. - Yeah.
- So you have to like close that loop. - [Sara] Right, so this is the classic- - And it's just all very
unlikely statistically, but you know, that's-
- Right. - Sufficiently... So you're saying there's a chance. - There is a chance.
- It's low probability but once you solve that,
once you close the loop, you can create a lot of those objects. - And that's what we're
trying to figure out, is what are the causal
constraints that close the loop. So there is this idea that's
been in the literature for a really long time, that was originally
proposed by Stuart Kauffman as really critical to the origin life called autocatalytic sets. So autocatalytic set is
exactly this property. We have A makes B, B makes C, C makes A, and you get a closed system. But the problem with the
theory of autocatalytic sets is incredibly brittle as a theory and it requires a lot
of ad hoc assumptions. Like you have to assume function, you have to say, "This thing makes B," it's not an emergent property, the association between A and B. And so the way I think about
it is much more general, if you think about these
histories that make objects, it's kind of like the structure
of the histories becomes... Collapses in such a way that these things are all in the same sort of causal structure, and that causal structure
actually loops back on itself to be able to generate some of the things that make the higher level structures. Lee has a beautiful example of
this actually in molybdenum. It's like the first
non-organic autocatalytic set. It's a self reproducing molybdenum ring, but it's like molybdenum and basically like if you
look at the molybdenum, it makes a huge molybdenum ring. I don't remember exactly how big it is, it might be like 150
molybdenum atoms or something. But if you think about
the configuration space of that object, you know,
it's exponentially large, how many possible molecules? So like why does the
entire system collapse on just making that one structure? If you start from like,
you know, molybdenum atoms that are maybe just like a
couple of them stuck together. And so what they see in this system is there's a few intermediate stages. So there's like some random events where the chemistry comes
together, makes these structures, and then once you get
to this very large one, it becomes a template
for the smaller ones, and then the whole system just reinforces its own production. - How did Lee find this molybdenum (both chuckle) closed loop. - If I knew how Lee's brain worked, I think I would understand
more about the universe, but I- - [Lex] This is not an algorithmic
discovery, it's a like- - No, but I think it goes to
the deepest roots of like, when he started thinking
about origins of life. So I like, I mean I don't
know all his history, but like what he's told me is, he started out in crystallography, and you know, there's some
things that he would just... You know, like people
would just take for granted about chemical structures that he was like deeply perplexed about. Like just like why are
these like really intricate, really complex structures forming so easily under these conditions? And he was really interested in life, but he started in that field. So he's just carried with him these sort of deep
insights from these systems that seem like they're totally not alive, and just like these metallic chemistries, into actually thinking about
the deep principles of life. So I think he already knew a lot about that chemistry. And he also, you know... Assembly theory came from him thinking about how these systems work. So he had some intuition
about what was going on with this molybdenum ring. - The molybdenum might
be able to be the thing that makes a ring. - They knew about them for a long time, but they didn't know that the mechanism of why that particular structural form was autocatalytic feedback. And so that's what they
figured out in this paper. And I actually think that paper is revealing some of the mechanism of the origin of life transition, 'cause really what you see, like the origin of life is basically like, you should have a combinatorial explosion of this space of possible structures that are too large to exhaust. And yet you see it
collapse on this, you know, really small space of possibilities, that's mutually reinforcing
itself to keep existing. That is the origin of life. - There's some set of structures that result in this
autocatalytic feedback. - Yeah.
- What is that? Some tiny, tiny, tiny, tiny percent? - I think it's a small space, but chemistry is very large, so- - And so like-
- There might be a lot of them out there,
but we don't know. - And one of them is the thing that probably started life on Earth. - That's right.
- Or many, many starts. - Yes.
- And it keeps starting maybe. - Yeah. I mean there's also all kinds
of other weird properties that happen around this
kind of phase boundary. So this other project that I have in my lab is focused
on the origin of chirality, which is, you know, thinking about... So chirality is this property of molecules that they can come in mirror image forms. So like just like... Chiral literally means hand, so your left and right hand are what's called non-super imposable, because if you try to
lay one on the other, you can't actually lay them
directly on top of each other, and that's the property
being a mirror image. So there's this sort
of perplexing property of the chemistry life that no one's been able to
really adequately explain that all of the amino acids
in proteins are left-handed, and all of the bases in RNA
and DNA are right-handed. And yet the chemistry of
these building block units, the amino acids and nucleobases is the same for left and right-handed. So you have to have like some
kind of symmetry breaking, where you go from these chemistries that seem entirely equivalent to only having one chemistry
take over as the dominant form. And for a long time, I had been really... I actually did my PhD on
the origin of chirality. I was working on it as like a symmetry breaking
problem in physics. This is how I got started
in the origin of life, and then I left it for a long time, 'cause I thought it was like one of the most boring
problems in the origin of life, but I've come back it, 'cause I think there's something
really deep going on here related to this like
combinatorial explosion of the space of possibilities. But just to get to that point, like this feature of this handedness has been the main focus, but people take for granted the existence of chiral molecules at all, that this property of having a handedness. And they just assume that, you know, like it's just a generic
feature of chemistry. But if you actually look at molecules, if you look at chemical space, which is like the space
of all possible molecules that people can generate, and you look at small molecules, things that have less than
about seven to 11 heavy atoms, so things that are not hydrogen. Almost every single molecule
in that space is achiral, like doesn't have a chiral center. So it would be like a spoon. A spoon doesn't have a... Like it's the same as its mirror image. It's not like a hand that's
different than its mirror image. But if you get to like
this threshold boundary, above that boundary, almost
every single molecule is chiral. So you go from a universe where almost nothing
has a mirror image form. There's no mirror image
universe of possibilities, to this one where every single structure has pretty much a mirror image version. And what we've been looking at in my lab is that it seems to be the case that the origin of life transition happens around the time when you
start accumulating... You push your molecules to
a large enough complexity that chiral molecules
become very likely to form, and then there's a cascade
of molecular recognition where chiral molecules
can recognize each other, and then you get this sort
of autocatalytic feedback and things self-reinforcing. - So is chirality in itself
an interesting feature or just an accident? - No, it's a super interesting feature. I think chirality breaks
symmetry in time not space. So we think of it as a spatial property, like a left and right hand, but if I choose the left hand, I'm basically choosing
the future of that system, for all time, because I've
basically made a choice between the ways that that
molecule can now react with every other object
in its chemical universe. - Oh, I see.
- And so you're actually... Like when you have this
splitting of making a molecule that now has
another form it could have had, by the same exact atomic composition, but now it's just a mirror image isometry, you're basically splitting
the universe of possibilities every time. - Yeah, in two.
- In two, but molecules can have more
than one chiral center, and that's not the only
symmetry that they can have. So this is one of the reasons that Taxol fills 1.5 universes of space. It's all of these spatial permutations that you do on these objects that actually makes the space so huge. So the point of this
sort of chiral transition that I'm putting out is, chirality is actually a signature of being in a complex chemical space. And the fact that we think
it's a really generic feature of chemistry and it's really prevalent, is because most of the
chemistry we study on Earth is a product already of life. And it also has to do with
this transition in assembly, this transition in possibility spaces, because I think there's
something really fundamental going on at this boundary, that you don't really need to go that far into chemical space if you can... To actually see life in
terms of this depth in time, this depth in symmetries of objects, in terms of like chiral symmetries, or this assembly structure. But getting past this boundary that's not very deep in
that space requires life. It's a really weird property, and it's really weird that
so many abrupt things happen in chemistry at that same scale. - So would that be the
greatest invention ever made on Earth in its evolutionary history? So I really like that formulation of it. Nick Lane has a book
called, "Life Ascending," where he lists the 10 great
inventions of evolution, the origin of life being first, and DNA, the hereditary material that encodes the genetic instructions for all living organisms. Then photosynthesis, the
process that allows organisms to convert sunlight into chemical energy, producing oxygen as a byproduct. The complex cell, eukaryotic cells, which contain a nucleus and organelles, arose from simple bacterial cells. Sex, sexual reproduction. Movement, so just the ability to move, under which you have the predation, the predators and ability
of living organisms- - Oh, I like that movement's
- To find food. - In there, that's cool. - Yeah, but movement includes a lot of interesting stuff in there, like predator prey dynamic. - Right.
- Which, not to romanticize, nature is metal. That seems like an important one. I don't know. It's such a computationally powerful thing to have a predator and prey. - Well, it's efficient for things to eat other things
that are already alive, 'cause they don't have
to go all the way back to the base chemistry. - Well that, but maybe
I just like deadlines, but it creates an urgency. You're gonna get eaten. - You gotta live. - Yeah, like the survival. It's not just the static environment you battle against, you're like- - Yeah.
- The dangers against which you're trying
to survive are also evolving. This is just a much faster way to explore the space of possibilities. - I actually think it's a gift
that we don't have much time. - Yes. Sight, the ability to see. So the increasing complexifying
of sensory organisms. Consciousness and death. The concept of programmed cell death. These are all inventions. - Yeah.
- Along the line. - I like invention as a word
for them. I think that's good. - Which are the more
interesting inventions to you? Origin of life? Because you kind of are not glorifying the origin of life itself. There's a process-
- No, I think the origin of life is a continual process, that's why. I'm interested in the first transition in solving that problem, 'cause I think it's the hardest, but I think it's happening all the time. - When you look back at
the history of Earth, like what are you impressed happened? - I like sight as an invention, 'cause I think having sensory perception and trying to "comprehend the world," to use anthropocentric terms, is like a really critical feature of life. And I also... It's interesting the way that sight has complexified over time, right? So like if you think
at the origin of life, nothing on the planet could see, right? So like for a long
time, life had no sight. And then, you know, like
photon receptors were invented. And then when multicellularity evolved, those cells eventually grew into eyes and we had the multicellular eye. And then it's interesting,
when you get to societies, like human societies, that we invent even better
technologies of seeing, like telescopes and microscopes, which allow us to see
deeper into the universe or at smaller scales. So I think that's pretty profound, the way that sight has
transformed the ability of life to literally see the reality
in which it's existing in. I think consciousness is also obviously deeply interesting. I've gotten kind of
obsessed with like octopus. I don't like, I... They're just so weird, and the fact that like they
evolved complex nervous systems kind of independently is
like, seems very alien. - Yeah, there's a lot
of alien like organisms. That's another thing I saw in the jungle. - Yeah.
- Just things that are like, "Oh, okay. They make one of those, huh?" It just feels like there's-
- Do you have any examples? - There's a frog that's as
thin as a sheet of paper. - Oh wow.
- And I was like, "What?" And it gives birth
through like pores, like- - Oh, I've seen videos of that. It's so gross when the babies come out. - Yes.
- Did you see that? Like in person-
- Yes. - Like the babies coming out?
- Oh no, no. I saw the... Without the-
- Have you seen videos of that? It's so gross. It's one of the grossest
things I've ever seen. (laughs) - Well, gross is just the other
side of beautiful I think. - Yeah.
- 'Cause it's like, "Oh wow, that's possible." - I guess if I was one of those frogs, I would think that was
the most beautiful event I'd ever seen. Although like human childbirth
is not that beautiful either. (Sara laughs)
- Yeah, it's all a matter of perspective. - Well we come into
the world so violently, it's just like... It's amazing. - Well, I mean the world
is a violent place. - Yeah.
- So again, another... It's just another side of the coin. - You know what, this actually makes me think
of one that's not up there, which I do find really incredibly amazing, is the process of like
the germline cell in... You know, in organisms. Like basically like every
living thing on this planet at some point in its life has
to go through a single cell, and this whole issue of like development, like the developmental
program is kind of crazy. Like how do you build
you out of a single cell? How does a single cell
know how to do that? Like, you know, pattern formation of a multicellular organism, obviously like evolves with DNA. But there's a lot of stuff happening there about when cells take
on certain morphologies and things that people don't understand, like the actual shape formation mechanism. And a lot of people study that and it's... And there's a lot of advances
being made now in that field. I think it's pretty shocking though that like how little we
know about that process. And often it's left off of people's lists. It's just kind of interesting. Embryogenesis is fascinating. - Yeah, 'cause it... You start from just one cell. - Yeah, and the genes in all
the cells are the same, right? So like the differentiation has to be something that's like much more about like the
actual like, you know, expression of genes over time, and like how they get switched on and off, and also the physical environment of like the cell interacting
with other cells, and there's just a lot of stuff going on. - Yeah, the computation, the
intelligence of that process- - Yes.
- Might be like the most important thing to understand, and we just kind of don't
really think about it. - Right.
- We think about the final product. - Yeah.
- Maybe the key to understanding the organism
is understanding that process, not the final product - Probably, yes. I think most of the things about understanding anything about what we are, are embedded in time. - [Lex] Well of course you would say that. - I know, so predictable. (laughs) It's turning into a
deterministic universe. - It always has been. Always was, like the meme. - Yeah, always was, but
it won't be in the future. - Well that's... Before we talk about the future, let's talk about the
past, the assembly theory. - Yes.
- Can you explain assembly theory to me? I listened to Lee talk
about it for many hours and I understood nothing. No, I'm just kidding.
(Sara laughs) I just wanted to take another... Well, you've been
already talking about it, but just another-
- Yeah. - What from a big picture view is the assembly theory way
of thinking about our world, about our universe. - Yeah. I think the first thing is, you know, that like the observation that, life seems to be the only
thing in the universe that builds complexity in
the way that we see it here, and complexity is obviously
like a loaded term. So I'll just use assembly instead, 'cause I think assembly is more precise. But the idea that like, you know, all the things on your desk here, from your computer, to the pen, to, you know, us sitting here, don't exist anywhere else in
the universe as far as we know. They only exist on this planet. And it took a long evolutionary
history to get to us, is a real feature that
we should take seriously as one that's deeply embedded
in the laws of physics and the structure of the
universe that we live in. Standard physics would say that, you know, all of that complexity traces back to the infinitesimal deviations in like the initial state of the universe, that there was some order there. I find that deeply unsatisfactory, and what assembly theory says, that's very different, is that the universe is
basically constructing itself. And when you get to these
combinatorial spaces like chemistry, where the space of
possibilities is too large to exhaust them all, you can only construct things along historically contingent paths. Like you basically have causal
chains of events that happen to allow other things
to come into existence. And that this is the way that complex objects get formed, is basically on scaffolding on
the past history of objects, making more complex objects, making more complex objects. That idea in itself is
easy to state and simple, but it has some really
radical implications as far as what you think is
the nature of the physics that would describe life. And so what assembly theory does formally, is try to measure the boundary in the space of all things that, you know, chemically
could exist, for example, like all possible molecules. Where is the boundary
above which we should say, "These things are too complex to happen outside of an
evolutionary chain of events, outside of selection." And we formalize that
with two observables, one of them is the copy
number of the object. So how many of the object did you observe? And the second one is,
what's the minimal number of recursive steps to make it? So if you start from
elementary building blocks like bonds for molecules and you put them together, and then you take things
you've made already and built up to the object, what's the shortest number
of steps you had to take? And what Lee's been able to
show in the lab with his team is that for organic chemistry,
it's about 15 steps. And then you only see
molecules that, you know... Only molecules that we observe, that are past that threshold,
are ones that are in life. And in fact, one of the
things I'm trying to do with this idea of like trying to actually
quantify the origin of life as a transition in... Like a phase transition assembly theory, is actually be able to explain why that boundary is where it is, 'cause I think that's
actually the boundary that life must cross. So the idea of going back to this thing we were talking about before about these structures that can reinforce their own existence and move past that boundary. 15 seems to be that
boundary in chemical space. It's not a universal number. It will be different for
different assembly spaces, but that's what we've
experimentally validated so far, and then- - So literally 15, like
the assembly index is 15? - It's 15 or so for the
experimental data, yeah. - So that's when you start
getting the self-reinforcing? - That's when you have
to have that feature in order to observe
molecules in high abundance in that space. - So copy number is the
number of exact copies. That's what you mean by high abundance, and assembly index or the
complexity of the object is how many steps it took to create it. Recursive-
- Recursive, yeah. So you can think of objects in assembly theory as
basically recursive stacks of the construction steps to build them. So they're like, it's like... You take this step and then you make this object,
and you make it this object, and make this object, and then you get up to the final object, but that object is all of that history rolled up into the current structure. - What if you took the long way home- - You can't take the long way. - Why not?
- The long way doesn't exist. - It's a good song though. What do you mean the
long way doesn't exist? If I do a random walk from A to B, I'll eventually... If I start at A, I'll
eventually end up at B, and that random walk would be
much longer than the short. - No, if you look at objects and you... So we define something we
call the assembly universe, and assembly universe is ordered in time. It's actually ordered in the causation, the number of steps to produce an object, and so all objects in the
universe, are in some sense... Exist at a layer that's defined
by their assembly index, and the size of each layer
is growing exponentially. So what you're talking about, if you wanna look at the long
way of getting to an object, as I'm increasing the
assembly index of an object, I'm moving deeper and deeper into an exponentially growing space. And it's actually also the case that the sort of typical
path to get to that object is also exponentially growing with respect to the assembly index. And so if you want to try to make a more and more complex object, and you wanna do it by a typical path, that's actually an
exponentially receding horizon. And so most objects
that come into existence have to be causally very similar
to the things that exist, 'cause they're close by in that space, and they can actually get to it by an almost shortest
path for that object. - Yeah, the almost shortest
path is the most likely like by a lot. - By a lot.
- Okay. So if you see a high copy number. - Yeah, imagine yourself-
- A copy number of greater than one. - Yeah, I mean basically we live... The more complex we get, we live in a space that is
growing exponentially large, and the ways of getting to objects in the space are also
growing exponentially large. And so we're this kind of recursively like stacked structure of like all of these objects that are clinging onto
each other for existence, and then they like grab something else, and are like able to bring
that thing into existence, 'cause it's kind of similar to them. - But there is a phase transition. There is a- - There is a transition.
- There is a place where you would say, "Oh-" - I think it's actually abrupt. I've never been able to say
that in my entire career before. I've always gone back and forth about whether the origin
of life was kind of gradual or abrupt, I think it's very abrupt. - Poetically, chemically-
- Life snaps into existence. - Oh it snaps, okay, that's very beautiful.
- It snaps. - Okay, but-
- We'll be poetic today. But no, I think there's like
a lot of random exploration and then there's a like... And then the possibility space just collapses on the
structure kind of really fast. That can reinforce its own existence, because it's basically
fighting against non-existence. - Yeah, you tweeted, "The
most significant struggle for existence in the evolutionary process is not among the objects that do exist, but between the ones that do, and those that never have the chance to. - Yeah.
- This is where selection does most of its causal work." The objects that never
get a chance to exist. - Yeah.
- The struggle between the ones that never get a chance to
exist and the ones that... Okay, what's that line exactly? - I don't know, we can make
songs out of all of these. - What are the objects that never get a chance to exist? What does that mean? - So there was this website, I forgot what it was, but it's like a neural network that just generates a human face, and it's like, "This
person does not exist." I think that's what it's called, right? So you can just click on that all day, and you can look at people
all day that don't exist. - Yeah.
- All of those people exist in that space of
things that don't exist. - Yeah, but there's the real struggle. - Yeah, so the struggle of the quote, the struggle for existence is, you know, that goes all the way back to Darwin's writing about
natural selection, right? So like the whole idea of
survival of the fittest is everything struggling to exist, this predator prey dynamic, and the fittest survive, and so the struggle for existence is really what selection is all about. And that's true, we do
see things that do exist competing to continue to exist. But each time that... Like if you think about
this space of possibilities and you know, each time the universe, you know, generates a new structure, or like an object that exists, generates a new structure
along this causal chain. It's generating something that exists, that never existed before. And each time that we make
that kind of decision, we're excluding a huge
space of possibilities. And so actually like as this process of increasing assembly index, it's not just that like the space that these objects exist in
is exponentially growing, but there are objects in that space that are exponentially
receding away from us. So they're becoming exponentially less and less likely to ever exist, and so existence excludes
a huge number of things. - Just because of the accident
of history, how it ended up. - Yeah, it is in part an accident, because I think some of the structure that gets generated is
driven a bit by randomness. I think a lot of it, you know, so... You know, one of the
conceptions that we have in assembly theory is, you know, the universe
is random at its base. You can see this in chemistry, like unconstrained chemical
reactions are pretty random. And also quantum mechanics, you know, like there's lots of places
that give evidence for that. And deterministic structures emerge by things that can causally
reinforce themselves and maintain persistence over time. And so we are some of the
most deterministic things in the universe. And so like we can generate
very regular structure, and we can generate new structure along a particular lineage. But the possibility space
at the sort of tips, like the things we can
generate next is really huge. So there's some stochasticity
in what we actually, you know, instantiate as like the next structures that get built in the biosphere. It's not completely deterministic, 'cause the space of future possibilities is always larger than the
space of things that exist now. - So how many instantiations
of life is out there, do you think? So how often does this happen? What we see happen here on Earth? How often is this process repeated throughout our galaxy,
throughout the universe? - So I said before, like right now, I think the origin of life is
a continuous process on Earth. Like, I think this idea of
like combinatorial spaces that our biosphere generates,
not just chemistry, but other spaces, often
cross this threshold where they then allow themselves to persist with particular
regular structure over time. So language is another
one where, you know, like the space of, you know,
possible configurations of the 26 letters of the English alphabet is astronomically large, but we use with very high
regularity, certain structures. And then we associate meaning to them because of the regularity of like how much we use them, right? So meaning is an emergent
property of the causation and the objects and like
how often they recur, and what the relationship
of the recurrence is to other objects. - Meaning is the emergent property. Okay, got it.
- Well this is why you can play with
language so much actually. So words don't really carry meaning, it's just about how
you lace them together. - Yeah, but from where does the- - But you don't have a lot of room... Obviously, as a speaker
of a given language, you don't have a lot of room
with a given word to wiggle. But you have a certain amount of room to push the meanings of words. - Yeah.
- And I do this all the time and you have to do it with
the kind of work that I do. Because if you want to
discover an abstraction, like some kind of concept that we don't understand yet, it means we don't have the language. And so the words that we have are inadequate to describe the things. This is why we're having a hard time talking about assembly theory, 'cause it's a newly emerging idea. And so I'm constantly playing with words in different ways to try
to convey the meaning that is actually behind the words, but it's hard to do. - So you have to wiggle
within the constraints. - Yes, lots of wiggle. - The great orators are
just good at wiggling. - Do you wiggle? (laughs) - I'm not a very good wiggler, no. This is the problem. This
is part of the problem. - No, I like playing with words a lot. You know, it's very funny 'cause you know, like I know you talked
about this with Lee, but like, people were so offended by the writing of the paper
that came out last fall, and it was interesting because the ways that we use words were not the way that
people were interacting with the words. And I think that was part of the mismatch, where we were trying to
use words in a new way, 'cause we were trying to describe
something that, you know, hadn't been described adequately before. But we had to use the words
that everyone else uses for things that are related, and so it was really interesting to watch that clash play out in real time, for me, being someone that tries to be so precise with my word usage, knowing
that it's always gonna be vague. - Boy, can I relate. It's like, what is truth? Is truth the thing you meant
when you wrote the words? Or is truth the thing
that people understood when they read the words? - Oh yeah.
- I think that compression mechanism into language is a really interesting one, and that's why Twitter is a nice exercise- - I love Twitter.
- You get to write a thing, and you think a certain
thing when you write it, and then you get to see all
these other people interpret it all kinds of different ways. - I use it as an experimental
platform for that reason. - I wish there was a higher diversity of interpretation mechanisms
applied to tweets. Meaning like-
- Oh. - All kinds of different
people would come to it. Like some people that see
the good in everything and some people that are ultra cynicals. - Yeah.
- A bunch of haters and a bunch of lovers and a bunch of- - Maybe they could do better jobs with presenting material to people. Like, you know, they ran like... How things, you know, it's
like usually based on interest, but I think it would be
really nice if you got like, 10% of your Twitter feed was random stuff sampled from other places,
that'd be kind of fun. - True. I also would love to
filter, just like bin, the response to tweets by like the people that
hate on everything. - Yes.
- The people that are- - Oh, that would be fantastic. - The people that are like
super positive about everything, and then that'll just kind of, I guess, normalize the response. - Yeah.
- Because then it'd be cool to see if the people that are usually
positive about everything are hating on you, or like totally don't understand, or completely misunderstood. - Yeah, usually takes a lot
of clicking to find that out. Yeah, so it'd be better
if it was sorted, yeah. - The more clicking you do, the more damaging it is to the soul.
- Yeah. It's like instead of like... Like you could have the blue check, but you should have like, are
you a pessimist, an optimist? - There's a lot of-
- Chaotic neutral? (laughs) - A whole rainbow of checks. And then you realize
there's more categories than we can possibly express in colors. - Yeah, of course. People are complex. - That's our best feature. I don't know how we got
to the wiggling required, given the constraints of language, because I think we started about
me asking about alien life, which is, how many different times did the phase transition happen elsewhere? Do you think there's other
alien civilizations out there? - This goes into like the, you know, like are you on the
boundary of insane or not? But you know, when you
think about the structure of the physics of what we are that deeply, it really changes your
conception of things. And you know, going to
this idea of the universe, you know, being kind of
small in physical space compared to how big it is in
time and like how large we are. It really makes me question about whether there's any other structure that's like this giant crystal in time, this giant causal structure, like our biosphere/technosphere is, anywhere else in the universe. - Why not?
- I don't know. - Just because this one is gigantic doesn't mean there's
no other gigantic ones- - Right, but I think when the
universe is expanding, right? It's expanding in space, but in assembly theory it's
also expanding in time. And actually that's driving
the expansion in space, and expansion in time is
also driving the expansion in the sort of combinatorial
space of things on our planet. So that's driving the sort of, you know, pace of technology and
all the other things. So time is driving all of these things, which is a little bit crazy to think that the universe is just getting bigger because time is getting bigger. But like this sort of visual that gets built in my brain about that is like this structure that we're building on this planet is packing more and more time in this very small volume of space, right? 'Cause our planet hasn't
changed its physical size in 4 billion years, but there's like a ton of
causation and recursion and time, whatever word you wanna use, information, packed into this. And I think this is also, you know, embedded in sort of the
virtualization of our technologies or the abstraction of language and all of these things, these things that seem really abstract are just really deep in time. And so what that looks like is, you have a planet that becomes
increasingly virtualized, and so it's getting
bigger and bigger in time, but not really expanding out in space, and the rest of space is like
kind of moving away from it. Again, it's a sort of
exponentially receding horizon. And I'm just not sure how far into this evolutionary
process something gets, if it can ever see that there's another
such structure out there. - What do you mean by
virtualized in that context? - Virtual as sort of a
play on virtual reality and like simulation theories, but virtual also in a sense of, you know, we talk about virtual
particles in particle physics, which, you know, they are very critical to doing calculations about
predicting the properties of real particles, but we
don't observe them directly. So what I mean by virtual here is, virtual reality for me, things that appear
virtual, appear abstract, are just things that
are very deep in time, in the structure of
the things that we are. So if you think about you as
a 4 billion year old object, the things that are a part of you, like your capacity use
language or think abstractly or have mathematics,
are just very, you know, like deep, temporal structures. That's why they look like
they're informational and abstract, is because they're like... They're existing in this
temporal part of you, but not necessarily spatial part. - Just because I have a 4
billion year old history, why does that mean I can't
hang out with aliens? - There's a couple ideas
that are embedded here. So one of them comes, again, from Paul, he wrote this book years
ago about, you know, like the eerie silence
and why we're alone. And he concluded the book with
this idea of quintelligence or something, but like
this idea that like, really advanced intelligence would basically just build
itself into a quantum computer and it would wanna operate
in the vacuum of space, 'cause that's the best place
to do quantum computation, and it would just like run out all of its computations indefinitely, but it would look completely dark to the rest of the universe. And I don't think.... As typical, like, I don't
think that's actually like the right physics, but I think something about that idea, as I do with all ideas,
is partially correct. And Freeman Dyson also
had this amazing paper about how long life could persist in a universe that was
exponentially expanding. And his conception was like, if you imagine analog life form, it could run slower and
slower and slower and slower and slower as a function of time. And so it would be able
to run indefinitely, even against an exponentially
expanding universe, because it would just
run exponentially slower. And so I guess part of
what I'm doing in my brain is putting those two things together along with this idea
that we are building... You know, like if you
imagine, with our technology, we're now building
virtual realities, right? Like things we actually
call virtual reality, which required, you know,
four billions years of history and a whole bunch of data to basically embed them in
a computer architecture. So now you can put like, you
know, an Oculus headset on and think that you're
in this world, right? And what you really are embedded in is in a very deep temporal structure. And so it's huge in time,
but it's very small in space, and you can go lots of places
in the virtual space, right? But you're still stuck in
like your physical body and like sitting in the chair. And so, you know, part of it is, it might be the case that
sufficiently evolved biospheres kind of virtualize themselves, and they internalize their universe and their sort of
temporal causal structure, and they close themselves off
from the rest of the universe. - I just don't know if a
deep temporal structure necessarily means that you're closed off. - No, I don't either. So that's kind of my fear. So I'm not sure I'm
agreeing with what I say. I'm just saying like, this
is one sort of conclusion and you know, like in
my most sort of like... It's interesting, 'cause I
don't do psychedelic drugs, but when people describe to me, like your thing with the faces and stuff, and like I have... You know, I've had a lot of
deep conversations with friends that have done psychedelic
drugs for intellectual reasons and otherwise, but I'm always like, "Oh, it sounds like you're
just doing theoretical physics. Like that's what brains do on
theoretical physics." (laughs) So I live in these like
really abstract spaces most of the time, but there's also this
issue of extinction, right? Like extinction events
are basically pinching off an entire, like, causal structure. One of these like... I'm gonna call them time crystals, I don't like know what... But there's like these
very large objects in time, pinching off that whole
structure from the rest of it. And so it's like, if you
imagine that sort of same thing in the universe, you know, I once thought that sufficiently
advanced technologies would look like black holes. - That would be just
completely imperceptible to us. - Yeah. So there might be lots
of aliens out there. Maybe that's the explanation
for all the singularities, they're all pinched off causal structures that virtualized their reality and kind of broke off from us. - Black holes in every way,
so like untouchable to us or unlikely to be detectable by us- - Right.
- With whatever sensory mechanisms we have. - Yeah, but the other
way I think about it is, there is probably,
hopefully life out there. So like I do work on
life detection efforts in the solar system, and I'm trying to help with the
Habitable Worlds Observatory mission planning right now, and working with like the
bio signatures team for that. Like to think about
exoplanet bio signatures. So like I have some optimism
that we might find things, but there are the challenges that we don't know the
likelihood for life, like, which is what you were talking about. So if I get to a more grounded discussion, what I'm really interested in doing is trying to solve the origin of life so we can understand how
likely life is out there. So I don't think that the... I think that the problem
of discovering alien life and solving the origin of
life are deeply coupled, and in fact are one and the same problem. And that the first contact with alien life will actually be in an
origin of life experiment, but that part I'm super interested in. And then there's this other feature that I think about a lot, which is, our own technological phase of
development as sort of like, what is this phase in the
evolution of life on a planet. If you think about a
biosphere emerging on a planet and evolving over billions of years and evolving into a technosphere, when a technosphere can move off planet and basically reproduce
itself on another planet, now you have biospheres
reproducing themselves, basically. They have to go through
technology to do that. And so there are ways of thinking about sort of the nature of intelligent life and how it spreads in that capacity, that I'm also really excited
about and thinking about. And all of those things
for me are connected. Like we have to solve the origin of life in order for us to get off planet, because we basically have to
start life on another planet, and we also have to
solve the origin of life in order to recognize
other alien intelligence. Like all of these things are like literally the same problem. - Right, understanding the
origin of life here on Earth is a way to understand ourselves and to... Understanding ourselves is a prerequisite for being able to detect other
intelligent civilizations. I, for one, take it for what
it's worth, on ayahuasca, one of the things I did is
zoom out, like aggressively, at like a spaceship. And it would always go
quickly through the galaxy, and from the galaxy to this
representation of the universe. And at least for me,
from that perspective, it seemed like it was full of alien life. Not just alien life, but intelligent life- - I like that.
- And conscious life. So like, I don't know how
to convert it into words. It's more like a feeling,
like you were saying. - Yeah.
- A feeling, convert it to a visual,
to convert it to words. So I had a visual with it, but really it was a feeling, that it was just full
of this vibrant energy, that I was feeling when I'm looking at the people in my life- - Yeah.
- And full of gratitude, but that same exact thing is
everywhere in the universe. - Right.
- So- - I totally agree with this, like that visual, I really love. And I think we live in a universe that like generates life and purpose, and like it's part of the
structure of just the world. And so maybe like this sort
of lonely view I have is, I never thought about it this way until you were describing that. I was like, "I wanna
live in that universe." And I'm like a very optimistic person and I love building visions of reality that are positive, but I think for me right now,
in the intellectual process, I have to tunnel through this
particular way of thinking about the loneliness
of being like separated in time from everything else, which I think like we also all are, because time is what
defines us as individuals. - So part of you is drawn to the trauma of being alone deep-
- Yeah. - In a physics sense.
- Yeah, but also part of what I mean is, like you have to go through ideas you don't necessarily agree with to work out what you're
trying to understand. And I'm trying to be inside this structure so I can really understand it. And I don't think I've
been able to like... Like I'm so deeply embedded in what we are intellectually, right now, that I don't have an ability
to see these other ones that you're describing, if they're there. - Well, one of the things
you kind of described that you already spoke to, you call it the great perceptual filter. - Yeah.
- So there's the famous great filter, which is basically the idea that there's some really powerful moment in every intelligent civilization where they destroy themselves. - Yeah.
- That explains why we have not seen aliens. And you're saying that
there's something like that in the temporal history of the
creation of complex objects, that at a certain point
they become an island, an island too far to reach
based on the perceptions. - I hope not, but yeah,
I worry about it, yeah. - But that's basically meaning, there's something fundamental
about the universe, where the more complex you become, the harder it will be to
perceive other complex- - Yeah, I mean just think about us with microbial life, right? Like we used to once be cells, and for most of human history, we didn't even recognize
cellular life was there until we built a new
technology, microscopes, that allowed us to see them, right? So it's kind of weird, right? Like things that we-
- And they're close to us. - They're close, they're everywhere. - But also in the history
of the development of complex objects, they're pretty close. - Yes, super close. Super close. Like yeah, I mean everything on this planet is like. (laughs) It's like pretty much the same thing. Like the space of
possibilities is so huge, it's like we're virtually identical. - So how many flavors or kinds of life do
you think are possible? - I'm like trying to imagine all the little flickering
lights in the universe. Like in the way that you were describing, that was kind of cool. - I mean, it was awesome to me. It was exactly that. It was like lights.
- Yeah. - The way you maybe see a city, but yeah, a city from like up above, you see a city with the flickering lights, but there's a coldness to the city. - Yeah.
- There's some... You know that, you know, humans
are capable of good and evil and you could see like there's a complex feeling to the city. I had no such complex feeling
about seeing the lights of all the galaxies, whatever,
the billions of galaxies. - Yeah, this is kind of cool. I'll answer the question in a second, but I just maybe like... This idea of flickering lights and intelligence is
interesting to me, because I... You know, like we have
such a human-centric view of alien intelligences, that a lot of the work that
I've been doing with my lab is just trying to take inspiration from non-human life on Earth. And so I have this really
talented undergrad student that's basically building a model of alien communication based on fireflies. So one of my colleagues, Orit Peleg, she's totally brilliant, but she goes out with like GoPro cameras and like, you know,
films in high resolution, all these firefly flickering. And she has like this theory about how their signaling evolved to like maximally differentiate
the flickering pattern. So like she has a theory
basically that predicts, you know, like this species should flash like this. If this one's flashing like this, this other one's gonna
do it at a slower rate, so that they... You know, like they can
distinguish each other living in the same environment. And so this undergrad's
building this model where you have like a pulsar background of all these like giant
flashing sources in the universe and an alien intelligence, you know, wants to signal it's there, so it's flashing like a firefly. (laughs) And I just like the idea of thinking about non-human
aliens, so that was really fun. - The mechanism of the
flashing, unfortunately is... Like the diversity of that is very high and we might not be able
to see it, that's what- - Yeah, well I think there's some ways we might be able to
differentiate that signal. I'm still thinking about this part of it. So one is, like if you have pulsars and they all have a certain spectrum to their pulsing patterns, and you have this one
signal that's in there, that's basically tried to
maximally differentiate itself from all the other
sources in the universe. It might stick out in the distribution. Like there might be ways of actually being able to tell if it's an anomalous pulsar, basically. But I don't know if that
would really work or not. So, still thinking about it. - You tweeted, "If one wants to understand how truly combinatorially and compositionally
complex our universe is, they only need step into
the world of fashion." - Yeah.
- "It's bonkers how big the constructable
space of human aesthetics is." Can you explain? Can we explore the space
of human aesthetics? - Yeah, I don't know. I've been kind of obsessed with the... I never know how to pronounce it. Is it Schiaparelli? Like, you know, like they
have ears and things. Like it's such like a
weird, grotesque aesthetic, but like it's totally bizarre. But what I meant... Like I have a visceral experience when I walk into my closet. I have like a lot of- (laughs) - [Lex] How big is your closet? - It's pretty big. It's like, I do assembly
theory every morning when I walk in my closet, because I really like a very large, combinatorial, diverse palette, but I never know what I'm
gonna build in the morning. - Do you get rid of stuff?
- Sometimes. - Or do you have trouble
getting rid of stuff? Like- - I have trouble getting
rid of some stuff. It depends on what it is. If it's vintage, it's hard to get rid of, 'cause it's kind of hard to replace. It depends on the piece, yeah. - So you have... Your closet is one of those
temporal time crystals that- - Yeah, it's like-
- You get to visualize the entire history of the-
- It's a physical manifestation of my personality. - Right. So why is that a good visualization of the combinatorial and
composition and complex. - I think it's an interesting
feature of our species that we get to express ourself through what we wear, right? Like if you think about all those animals in the jungle you saw, like they're born the way they look, and then they're stuck with it for life. - That's true, I mean, it is one of the loudest, clearest, most consistent ways we
signal to each other- - Yeah.
- It's the clothing we wear. - Yeah, and it's highly dynamic. I mean you can be dynamic if you want to. Very few people are... There's a certain bravery, but it's actually more about confidence, willing to play with style and like... And play with aesthetics. And I think it's interesting when you start experimenting with it, how it changes the fluidity
of the social spaces and the way that you interact with them. - But there's also commitment. Like you have to wear
that outfit all today. - I know, I know. A big commitment. Do you feel like that
every morning? (laughs) - No. That's why-
- I feel like, this is a life commitment. (laughs) - So all I have is suits and
the black shirt and jeans. Those are the two outfits. - Yeah. Well see this is the thing though, right? It's simplifies your thought
process in the morning. So like I have other ways I do that. I park in the same exact parking spot when I go to work on the fourth
floor of a parking garage, because no one ever parks
on the fourth floor. So I don't have to remember
where I park my car. But I really like aesthetics
and playing with them. So I'm willing to spend part of my cognitive energy every morning trying to figure out
what I wanna be that day. - Did you deliberately think about the outfit you're wearing today? - Yep.
- Was there backup options? Or were you going back
and forth between some- - Three or four, but I really like- - Were they drastically different? - Yes.
- Okay.(laughs) Okay.
- And then even this one could have been really different, because like, you know, it's not just the sort of
jacket and the shoes and like, and the hairstyle. It's like the jewelry and the accessories. So like any outfit is a
lot of small decisions. - Well I think your current outfit is like a lot of shades of yellow. There's like a theme.
- Yes. Yeah.
- It's nice. I'm grateful that you did that. - Thanks.
- It's like it's own art form. - Yeah, yellow's my
daughter's favorite color, and I never really
thought about yellow much, but she's been obsessed with yellow. She's seven now and I don't
know, I just really love it. - I guess you can pick a color and just make that the constraint, and just go with it and understand the beauty-
- I'm playing with yellow a lot lately. Like this is not even the most yellow, 'cause I have black pants on, but I have... I've worn outfits that have probably five
shades of yellow in them. - Wow.
(Sara laughs) What do you think beauty is? We seem to... So underlying this idea of
playing with aesthetics is, we find certain things beautiful. - Yeah.
- What is it that humans find beautiful? And why do we need to
find things beautiful? - Yeah. You know, it's interesting. I mean I am attracted
to style and aesthetics, because I think they're beautiful, but it's much more because I
think it's fun to play with. And so I will get to the beauty thing, but I guess I wanna just
explain a little bit about my motivation this space, 'cause it's really an
intellectual thing for me. And you know, Stewart Brand
has this great infographic about the layers of like human society. And I think it starts with
like the natural sciences and like physics at the bottom, and it goes through all these layers, and it's like economics and
then like fashion is at the top, it's like the fastest moving
part of human culture. And I think I really like that, because it's so dynamic and so short in it's temporal longevity, contrasted with like
studying the laws of physics, which are like, you know, like
the deep structure reality, that I feel like bridging those scales tells me much more about
the structure of the world that I live in. - That said, there's
certain kinds of fashions, like a dude in a black
suit with a black tie seems to be less dynamic. - Yeah.
- It seems to persist through time. - Are you embodying this?
- Yeah, I think so. (both laugh) I think it just-
- I'd like to see you wear yellow, Lex. (laughs) - I wouldn't even know
what to do with myself. I would freak out. I wouldn't know how to- - You wouldn't know how
to be you, yeah, I know. This is amazing though, isn't it? Amazing, like you have
the choice to do it. But one of my favorite... Just on the question of beauty, one of my favorite fashion designers of all time is Alexander McQueen. And he was really phenomenal, but like his early... And actually, I kind of used
like what happened to him in the fashion industry
as a coping mechanism with our paper when... Like the nature paper in the fall when everyone was saying
it was controversial and how terrible that
like, you know like... But controversial is good, right? But like when Alexander McQueen,
you know, first came out with his fashion lines, he
was mixing horror and beauty, and people were horrified. It was so controversial. Like it was macabre. He had like... You know, like it looked like
there were blood on the models and like- - [Lex] That is beautiful. We're just looking at some pictures here. - Yeah, no, I mean his stuff is amazing. His first like runway line,
I think, was called Nihilism. I don't know if you could find it. You know, I mean he was really dramatic. He carried a lot of trauma with him. There you go, that's... Yeah. Yeah.
- Wow. - But he changed the fashion industry. His stuff became very popular. - That's a good outfit to
show up to a party. (laughs) - Right, right. But this gets at the question like, is that horrific or is it beautiful? And I think, you know,
he had a traumatic... He ended up committing suicide, and actually he left his death note on the descent of man. So he was a really deep person. - So I mean great fashion certainly has that kind of depth to it. - Yeah, it sure does. So I think it's the
intellectual pursuit, right? Like it's not... So this is like very highly intellectual, and I think it's a lot like
how I play with language, is the same way that I play with fashion, or the same way that I play with ideas in theoretical physics. Like there's always this space that you can just push things just enough. So they look like something
someone thinks is familiar but they're not familiar, and yeah, and I think that's really cool. - It seems like beauty doesn't
have much function, right? But it seems to also
have a lot of influence on the way we-
- It has tons of function. What do you mean it doesn't have function? - I guess sexual selection
incorporates beauty somehow. But why? Because beauty is a sign
of health or something? I don't even- - Oh, evolutionarily? Maybe. But then beauty becomes a
signal of other things, right? So it's really not like... And then beauty becomes an adaptive trait, so it can change with different... Like, you know, maybe
some species would think, well you thought the frog having babies come out
of its back was beautiful and I thought it was grotesque. Like there's not a universal
definition of what's beautiful. It is something that is
dependent on your history and how you interact with the world. And I guess what I like about beauty, like any other concept, is
when you turn it on its head. So, you know, maybe the traditional
conception of, you know, why women wear makeup and
they dress certain ways is because they wanna look beautiful and, you know, pleasing to people. And I just like to do it
'cause it's a confidence thing. It's about embodying the
person that I want to be and about owning that person, and then the way that people
interact with that person is very different than
if I didn't have the... Like, if I wasn't using
that attribute as part of... And obviously, that's influenced
by the society I live, and like what's aesthetically
pleasing things. But it's interesting to be
able to turn that around and not have it necessarily
be about the aesthetics, but about the power dynamics
that the aesthetics create. - But you're saying there's
some function to beauty, in that way. In the way you're describing, and the dynamic it creates
in the social interaction. - Well the point is, you're saying it's an adaptive trait for like sexual selection or something. And I'm saying that the adaptation that beauty confers is
far richer than that. And some of the adaptation
is about social hierarchy and social mobility and
just plain social dynamics. Like why do some people dress goth? It's 'cause they identify with a community and a culture associated with that, and they get, you know... And that's a beautiful aesthetic. It's a different aesthetic,
some people don't like it. - So it has the same
richness as does language. - Yes.
- It's the same kind of- - Yes, and I think too
few people think about the way that they... The aesthetics they build
for themselves in the morning and how they carry it in the world, and the way that other
people interact with that, because they put clothes on, and they don't think about
clothes as carrying function. - Let's jump from beauty to language. There's so many ways to
explore the topic of language. You called it... You said that language is parts of language or language in itself, and the mechanism of language
is a kind of living life form. You've tweeted a lot about this
in all kinds of poetic ways. Let's talk about the
computation aspect of it. You tweeted, "The world
is not a computation, but computation is our
best current language for understanding the world. It is important we recognize this so we can start to see the
structure of our future languages that will allow us to see deeper than computation allows us." So what's the use of language in helping us understand
and make sense of the world? - I think one thing that I feel like I notice much more viscerally than I feel like I hear
other people describe is that the representations in our mind and the way that we use language are not the things like... Actually, I mean, this
is an important point, going back to what Godel did, but also this idea of signs and symbols and all kinds of ways of separating them. There's like the word, right? And then there's like what the
word means about the world. And we often confuse those things. And what I feel very viscerally, I almost sometimes think I have some kind of like
synesthesia for language or something, and I just
like don't interact with it like the way that other people do. But for me, words are objects, and the objects are not the
things that they describe, they have like a different
ontology to them. Like they're physical things, and they carry causation
and they can create meaning, but they're not what we think they are. And also like the internal
representations in our mind, like the things I'm seeing about this room are probably, you know, like
they're small projection of the things that are
actually in this room. And I think we have such a difficult time moving past the way that
we build representations in the mind, and the way that we
structure our language, to realize that those are approximations to what's out there, and they're fluid, and we
can play around with them, and we can see deeper
structure underneath them, that I think, like, we're missing a lot. - Yeah, but also the life
of the mind is in some ways richer than the physical reality. - Sure.
- What's going on in your mind, it might be a projection- - Right.
- Actually here, but there's also all kinds of
other stuff going on there. - Yeah, for sure. I love this essay by Poincare about like mathematical creativity, where he talks about this
sort of like frothing of all these things, and then like somehow you
build theorems on top of it, and they become kind of concrete. But like, and I also think
about this with language, it's like there's a lot of
stuff happening in your mind, but you have to compress it
in this few sets of words to try to convey it to someone. So it's a compactification of the space, and it's not a very efficient one. And I think just recognizing that there's a lot that's
happening behind language is really important. I think this is one of the great things about the existential trauma
of large language models, I think is the recognition that language is not
the only thing required. Like there's something underneath it. Not by everybody. - Can you just speak to the feeling you have when
you think about words? So is there... Like what's the magic of words to you? Is it like... It almost sometimes feels like
you're playing with it? Like- - [Sara] Yeah, I was just gonna
say it's like a playground. - But you're almost like... I think one of the things you enjoy, maybe I'm projecting, is deviating, like using words in ways
that not everyone uses them. Like slightly sort of deviating
from the norm a little bit. - I love doing that in everything I do, but especially with language. - But not so far that
it doesn't make sense. - Exactly.
- So you're always like tethered to reality, to the norm, but like are playing with it, like basically fucking with
people's minds a little bit. I mean like, you know, and in so doing, creating a different perspective on another thing that's
been previous explored in a different way. - Yeah, it's literally
my favorite thing to do. - Yeah. Use words as one way to make people think. - Yeah, so I, you know... A lot of my sort of like, what happens in my mind when
I'm thinking about ideas is I've been presented
with this information about how people think about things, and I try to go around
to different communities and hear the ways that different... Whether it's like, you know, hanging out with a bunch of artists or philosophers or scientists, thinking about things, like they all think
about it different ways, and then I just try to figure out like, how do you take the structure of the way that we're talking about it and turn it slightly, so you have all the same pieces that everybody sees are there, but the description
that you've come up with seems totally different. So they can understand that there's... Like they understand the
pattern you're describing, but they never heard the
structure underlying it described the way that you describe it. - Is there words or terms you remember that disturbed people the most? Maybe the positive sense of disturbed. Assembly theory, I suppose, is one. - Yeah, I mean the first couple sentences of that paper disturbed people a lot, and I think they were
really carefully constructed in exactly this kind of way. - What was that? Let me look it up. - Oh, it was really fun. But I think it's
interesting, 'cause I do... You know, sometimes I'm
very upfront about it. I say I'm gonna use the same word in probably six different
ways in a lecture, and I will. - You write, "Scientists have grappled with reconciling biological evolution with immutable laws of the
universe defined by physics. These laws underpin life's origin, evolution and the-" (Sara faintly speaking) - [Sara] When he was here too. (laughs) - "The development of human culture." Well he was... I think your for words
runs deeper than Lee's. - Yeah, for sure. I mean this is part of the sort of brilliant thing about
our collaboration is, you know, complimentary skillsets. So I love playing with the
abstract space of language, and it's a really interesting playground when I'm working with Lee, because he thinks at a much deeper level of abstraction than can
be expressed by language. And the ideas we work on are hard to talk about for that reason. - What do you think about
computation as a language? - I think it's a very poor language. A lot of people think
is a really great one, but I think it has some nice properties, but I think the feature of it
that you know is compelling is this kind of idea of universality, that like you can... If you have a language, you can describe things
in any other language. - Well, for me, one of the people who kind of revealed the
expressive power of computation, aside from Alan Turing, is Stephen Wolfram, through
all the explorations of like cellular automata type of objects that he did in a new kind
of science and afterwards. So what did he get from that? Like the kind of computational worlds that are revealed through even something as simple
as cellular automata. Like, it seems like
that's a really nice way to explore languages that are far outside our human languages, and do so rigorously, and understand how those
kinds of complex systems can interact with each other, can emerge, all that kind of stuff. - I don't think that they're
outside our human languages. I think they define the boundary of the space of human languages. They allow us to explore
things within that space, which is also fantastic. But I think there is a
set of ideas that takes... And Stephen Wolfram has
worked on this quite a lot and contributed very significantly to it. And you know, I really
like some of the stuff that Stephen's doing with
like his physics project, but don't agree with a lot
of the foundations of it. But I think the space is
really fun that he's exploring. You know, there's this assumption that computation is at
the base of reality, and I kind of see it at the top
of reality, not at the base, because I think computation
was built by our biosphere. It's something that happened after many billion years of evolution, and it doesn't happen in
every physical object. It only happens in some of them. And I think one of the reasons that we feel like the
universe is computational is because it's so easy for us as things that have the theory
of computation in our minds, and actually in some sense, it might be related to the
functioning of our minds and how we build languages
to describe the world and sets of relations
to describe the world. But it's easy for us to
go out into the world and build computers, and then we mistake
our ability to do that, with assuming that the
world is computational. And I'll give you a really simple example. This one came from John Conway. I, one time had a conversation with him, which was really delightful. He was really fun. But he was pointing out that if you, you know, string lights
in a barn, you know, you can program them to have your favorite one dimensional CA, and you might even be able
to make them, you know, do a like... Be capable of universal computation. Is universal computation a
feature of the string lights? - Well, no.
- No, it's probably not. It's a feature of the fact
that you as a programmer had a theory that you could embed in the physical architecture
of the string lights. Now what happens though is we get confused by
this kind of distinction between us as agents in the world that actually can transfer things that life does onto other
physical substrates, with what the world is. And so for example, you'll
see people, you know, studying the mathematics of
chemical reaction networks and saying, "Well, chemistry
is turning universal," or studying the laws of physics and saying, "The laws of
physics are turning universal." But anytime that you wanna do that, you always have to
prepare an initial state. You have to, you know... You have to constrain the rule space, and then you have to actually be able to demonstrate the
properties of computation. And all of that requires an agent or a designer to be able to do that. - But it gives you an
intuition if you look at a 1D or 2D cellular automata, it allows you to build an intuition of how you can have complexity emerge from very simple beginnings, very simple initial conditions. - I think that's the intuition that people have derived from it. The intuition I get from cellular automata is that the flat space
of an initial condition in a fixed dynamical law is not rich enough to describe an open-ended generation process. And so the way I see cellular automata, is they're embedded slices in a much larger causal structure. And if you wanna look
at a deterministic slice of that causal structure,
you might be able to extract a set of consistent rules that you might call a cellular automata, but you could embed them
as much larger space, that's not dynamical and is
about the causal structure and relations between all
of those computations, and that would be the space
cellular automata live in. And I think that's the space
that Stephen is talking about, when he talks about his Ruliad and these hypergraphs of all
these possible computations. But I wouldn't take
that as my base reality, because I think again, computation itself, this abstract property, computation, is not at the base of reality. - Look, can we just linger
on that Ruliad, this- - [Sara] Yeah, one Ruliad
add to rule them all. - Yeah, so what... This is part of Wolfram- - Yeah.
- Physics project. It's what he calls the
entangled limit of everything that is computationally possible. - Yeah.
- So what's your problem with the Ruliad? - Well, it's interesting. So Stephen came to a workshop
we had in the Beyond Center in the fall, and the workshop theme was, "Mathematics: Is It Evolved or Eternal." And he gave a talk about the Ruliad, and he was talking about how,
you know, a lot of the things that we talk about in the Beyond Center, like does reality have a bottom? You know, if it has a bottom, what is it? You know, like what's the- - I need to go to-
- We'll have you to one sometime. - This is great. Does reality have a bottom? - Yeah, so we had one that was... It was called infinite
turtles are ground truth. And it was really just about this issue. But the thing that was interesting, I think Stephen was trying
to make the argument that, you know, fundamental
particles aren't fundamental, gravitation is not fundamental. You know, these are just turtles, and computation is fundamental. And I just, I remember
pointing out to him, I was like, "Well,
computation is your turtle." And I think it's a weird turtle to have. - First of all, isn't it
okay to have a turtle? - It's totally fine to have a turtle. Everyone has a turtle. You can't build a theory without a turtle. - Yep.
- It's just... So it depends on the
problem you wanna describe. And actually, the reason
I can't get behind Stephen's ontology is I don't know what question
he's trying to answer. And without a question to answer, I don't understand why you're
building a theory of reality. - And the question you're
trying to answer is- - What life is.
- What life is, which another simpler way of phrasing that is how did life originate? - Well, I started working
on the origin of life, and I think what my challenge was there, was no one knew what life was. And so you can't really
talk about the origination of something if you don't know what it is. And so the way I would approach it is, if you wanna understand what life is, then proving that physics is
solving the origin of life. So there's the theory of what life is, but there's the actual demonstration that that theory is an
accurate description of the phenomena you aim to describe. So again, they're the same problem. It's not like I can
decouple origin of life from what life is. It's like that is the problem. And the point I guess I'm making about having a question is, no matter what slice of reality you take, what regularity of nature
you're gonna try to describe, there will be an abstraction that unifies that structure of reality, hopefully. And that will have a
fundamental layer to it, right? 'Cause you have to explain something in terms of something else. So if I wanna explain life for example, then my fundamental description of nature has to be something I think that has to do with time being fundamental. But if I wanted to describe, I don't know, the sort of interactions of
matter and light, you know, I have elementary
particles be fundamental. If I wanna describe electricity and magnetism in the 1800s, I have to have waves
be fundamental, right? So like you... Or in quantum mechanics, like it's a wave function
that's fundamental, 'cause that's the sort
of explanatory paradigm of your theory. So I guess I don't know
what problem saying, "Computation is fundamental" solves. - Doesn't he want to understand how does the basic quantum mechanics and general relativity emerge? - Yeah, but that-
- And cause time- - Right, so I think-
- Then that doesn't really answer an important question for us? - Well, I think that the issue is, general relativity and quantum
mechanics are expressed in mathematical languages, and then computation is
a mathematical language. So you're basically saying that maybe there's a more
universal mathematical language for describing theories of
physics that we already know. That's an important question, and I do think that's
what Steven's trying to do and do well. But then the question becomes, does that formulation of
a more universal language for describing the laws of
physics that we know now tell us anything new about
the nature of reality? Or is it a language? - And to you, languages are fundamental... It can't be fundamental. - The language itself is
never the fundamental thing. It's whatever it's describing. - So one of the possible
titles you were thinking about originally for the book is
"The Hard Problem of Life," sort of reminiscent of the
hard problem of consciousness. So you are saying that assembly theory is supposed to be answering the
question about what is life. So let's go to the other hard problems. You also say that's the
easiest of the hard problems, is the hard problem of life. So what do you think is
the nature of intelligence and consciousness? You think something like assembly theory can help us understand that? - I think if assembly theory is an accurate depiction
of the physics of life, it should shed a lot of
light on those problems. And in fact, I sometimes wonder if the problems of consciousness and intelligence are at all different than the problem of life generally. And I'm of two minds of it, but I in general try to... You know, like the process of my thinking is trying to regularize
everything into one theory. So pretty much every
interaction I have is like, "Oh, how do I fold that into..." And like, so I'm just building
this giant abstraction, that's basically trying to
take every piece of data I've ever gotten in my brain into a theory of what life is. And consciousness and intelligence are obviously some of the
most interesting things that life has manifest. And so I think they're very telling about some of the deeper features
about the nature of life. - It does seem like they're
all flavors of the same thing. But it's interesting to
wonder like at which stage does something that we
would recognize as life, in a sort of canonical, silly human way, and something that we would
recognize as intelligence. At which stage does that emerge? Like at which assembly
index does that emerge? And at which assembly
index is a consciousness something that we would
canonically recognize as consciousness? - Is this the use... Like this use of flavors, the same as you meant when you were talking
about flavors of alien... Like alien life. - Yeah, sure. Yeah. I mean it's same as the
flavors of ice cream and the flavors of fashion. - Yeah, like, but we were
talking about in terms of colors and like very nondescript. But the way that you just
talked about flavors now is more in like the space of
consciousness and intelligence. It was kind of like much more specific. - It'd be nice if there's
a formal way of expressing- - Quantifying flavors?
- Quantifying flavors. - Yeah.
- It seems like, I would order it life,
consciousness, intelligence probably. As like the order in which things emerge, and they're all just the same- - They're the same thing.
- We're using the word life differently here. I mean life sort of, when I'm talking about, what is a living versus a non-living thing at a bar with a person, I'm already like four or five
drinks in, that kind of thing. - Just that. (laughs)
- Like we're not being too philosophical. Like here's the thing that moves, and here's the thing that doesn't move. But maybe consciousness precedes that. It's a weird dance there with like... Is life proceed consciousness or consciousness proceed life. And I think that
understanding of what life is in the way you're doing, will help us disentangle that - Depending on what you wanna explain. As I was saying before, you have to assume
something's fundamental. And so because people can't
explain consciousness, there's a temptation for some people to wanna take consciousness
as fundamental, and assume everything else
is derived out of that. And then you get some people that wanna assume
consciousness preceded life. And I don't find either of those views particularly illuminating, I think... 'Cause I don't wanna assume a feminology before I explain a thing. And so what I've tried really hard to do is not assume, that I
think life is anything, except hold on to sort of the patterns and structures that seem to
be the sort of consistent ways that we talk about this thing, and then try to build a
physics that describes that. And I think that's a really
different approach than saying, you know, "Consciousness is this thing, you know, we all feel and
experience about things." I would wanna understand the regularities associated with that, and build a deeper
structure underneath that, and build into it. I wouldn't wanna assume that thing and that I understand that thing, which is usually how I
see people talk about it. - The difference between
life and consciousness. - Yeah.
- Which comes first. - Yeah, so I think if
you're thinking about this sort of thinking about living things as these giant causal structures, or these objects that are deep in time, or whatever language we end
up using to describe it, it seems to me that
consciousness is about... The fact that we have
a conscious experience is because we are these
temporally extended objects. So consciousness and the abstraction that we have in our minds is actually a manifestation
of all the time that's rolled up in us, and it's just because we're so huge, that we have this very large inner space that we're experiencing, that's not... And it's also separated off
from the rest of the world because we're the separate thread in time. And so our consciousness
is not exactly shared with anything else, because nothing else occupies
the same part of time that we occupy. But I can understand something about you maybe being conscious because you and I didn't
separate that far in the past, in terms of our causal histories. So in some sense we can
even share experiences with each other through language, because of that sort of
overlap in our structure. - Well then if consciousness is merely temporal separateness, then that comes before life. - It's not merely temporal separateness, it's about the depth in that time. So it's-
- Yes. - The reason that my conscious experience is not the same as yours is
because we're separated in time. The fact that I have
a conscious experience is because I'm an object
that's super deep in time, so I'm huge in time, and that means that there's a lot there that I am basically in some
sense, a universe onto myself, because my structure is so large relative to the amount
of space that I occupy. - But it feels like that's possible to do before you get anything like bacteria. - I think there's a horizon, and I don't know how
to articulate this yet, it's a little bit like the
horizon at the origin of life, where the space inside
a particular structure becomes so large that it has some access to a space that doesn't feel as physical. It's almost like this
idea of counterfactuals. So I think like the past
history of your horizon is just much larger
than can be encompassed in like a small configuration of matter. So you can like pull this
stuff into existence. This property is maybe
a continuous property, but there's something really different about human level physical systems, and human level ability
to understand reality. I really love David Deutsch's conception of universal explainers, and that's related to the
theory of universal computation. And I think there's some
transition that happens there. But maybe to describe
that a little bit better, what I can also say is like, what intelligence is in this framework? So you have these objects that are, you know, large in time. They were selected to exist by constraining the
possible space of objects to this particular... Like all of the matter is funneled into this particular
configuration of object over time, and so these objects
arise through selection, but the more selection that
you have embedded in you, the more possible selection
you have on your future. And so selection and evolution, we usually think about in the past sense, where selection happened in the past, but objects that are high
density configurations of matter that have a lot of selection in them are also selecting agents in the universe. So they actually embody
the physics of selection, and they can select on possible futures. And I guess what I'm saying
with respect to consciousness and the experience we have, is that there's something
very deep about that structure and the nature of how we
exist in that structure that has to do with how
we're navigating that space, and how we generate that space, and how we continue to
persist in that space. - Is there shortcuts we can take to artificially engineering
living organisms? Artificial life, artificial consciousness, artificial intelligence. So maybe just looking pragmatically at the LLMs we have now, do you think those can
exhibit qualities of life, qualities of consciousness, qualities of intelligence in the way we think of intelligence? - I mean I think they already do, but not in the way I
hear popularly discussed. So they're obviously
signatures of intelligence and a part of a ecosystem
of intelligence systems. But I don't know that
individually, you know, I would assign all the properties
to them that people have. It's a little like, so, you know, we talked about the
history of eyes before, and like how eyes scaled up
into technological forms, and language has also had a
really interesting history, and got much more interesting, I think, once we started writing it down, and then, you know, in
inventing books and things. But like, you know, every
time that we started storing language in a new way, you know, where we're kind of
existentially traumatized by it. So like, you know, the idea of written
language was traumatic, because it seemed like the
dead were speaking to us even though they were deceased, and books were traumatic because, you know, like suddenly
there were lots of copies of this information available to everyone and it was gonna somehow dilute it. And large language models
are kind of interesting, because they don't feel as static. They're very dynamic. But if you think about language in the way I was describing it before as, language is this very
large in time structure, and before it had been
something that was distributed over human brains as a dynamic structure, and occasionally we
store components of that very large dynamic structure in books or in written language. Now we can actually store the dynamics of that structure in a physical artifact, which is a large language model. And so I think about it almost like the evolution
of genomes in some sense, where, you know, there might've been like really primitive genes on
the first living things, and they didn't store
a lot of information, or they were like really messy. And then we, you know, like by the time you get
to the eukaryotic cell, you have this really
dynamic genetic architecture that's read writeable, right? And has all of these different properties. And I think large language models are kind of like the
genetic system for language in some sense, where it's allowing a sort of archiving that's highly dynamic. And I think it's very paradoxical to us, because obviously in human history, we haven't been used to
conversing with anything that's not human. But now we can converse basically with a crystallization
of human language in a computer, that's a
highly dynamic crystal, because it's a crystallization in time of this massive abstract structure that's evolved over human history, and is now put into a small device. - I think crystallization kind of implies a limit on its capabilities. - I think there's not a... I mean it very purposefully, because a particular
instantiation of a language model trained on a particular data set becomes a crystal of the
language at that time it was trained, but obviously we're
iterating with the technology and evolving it. - I guess the question is, when you crystallize it,
when you compress it, when you archive it, you're archiving some slice of the collective intelligence
- Yes. of the human species.
- That's right. - And the question is,
like how powerful is that? - Right? It's a societal
level technology, right? We've actually put collective
intelligence in a box. - Yeah, I mean, how much smarter is the
collective intelligence of humans versus a single human? And that's the question of AGI versus human level intelligence. Super human level intelligence versus human level intelligence. Like how much smarter can this thing... When done well, when we solve a lot of the
computation complexities, maybe there's some data complexities, and how to really archive this thing, crystallize this thing really well. - Yeah.
- How powerful is this thing gonna be? Like what's your thought? - I actually... I don't like the sort of
language we use around that, and I think the language really matters. So I don't know how to talk about how much smarter one human
is than another, right? Like usually we talk about abilities or particular talent someone has. And you know, going back to,
you know, David Deutsch's idea of universal explainers, it like... You know, adopting the
view that, you know, we're the first, you know, kinds of structures
our biosphere has built that can understand the rest of reality. We have this universal
comprehension capability. You know, he makes an argument that basically, we're the first things that actually are capable
of understanding anything. It doesn't mean an individual
understands everything, but like we have that capability. And so there's not a
difference between that and what people talk about with AGI. In some sense, AGI is
a universal explainer, but you know, like it
might be that a computer is much more efficient at doing, you know, I don't know, prime
factorization or something, than a human is, but it doesn't mean that
it's necessarily smarter or has a broader reach
of the kind of things that it can understand, than a human does. And so I think we really
have to think about, is it a level shift? Or is it, we're enhancing certain kinds
of capabilities humans have in the same way that we enhanced eyesight by making telescopes and microscopes. Are we enhancing capabilities
we have into technologies, and the entire global ecosystem
is getting more intelligent? Or is it really that we're building some super machine in a box that's gonna be smart and kill everybody? That sounds like a science... It's not even a science fiction narrative, it's a bad science fiction narrative. I just don't think it's actually accurate to any of the technologies we're building, or the way that we should
be describing them. It's not even how we should
be describing ourselves. - So the benevolence stories,
there's a benevolence system that's able to transform our economy, our way of life by just, you
know, 10X-ing the GDP of- - Well, these are human questions, right? I don't think they're
necessarily questions that we're gonna like outsource to an artificial intelligence. I think what is happening and will continue to happen, is there's a co-evolution between humans and technology that's happening. And we're coexisting in
this ecosystem right now, and we're maintaining
a lot of the balance, and for the balance to
shift to the technology would require some very bad human actors, which is a real risk. Or some sort of... I don't know, some sort
of dynamic that favors... Like I just don't know how that plays out without human agency actually trying to put
it in that direction. - It could also be how rapid the rate- - The rapid rate is scary. So like, I think the
things that are, you know, terrifying are, you know,
the ideas of deep fakes or you know, like, you know, all the kinds of issues
that become legal issues about artificial
intelligence technologies. And using them to control weapons or using them for, you know, like child pornography
or you know, like the... Or like, you know, faking
out that someone's, you know, loved one was kidnapped or
killed and it, you know... Like, there's all kinds of things that are super scary in this landscape. And all kinds of new
legislation needs to be built, and all kinds of guardrails
on the technology to make sure that people don't
abuse it need to be built, and that needs to happen. And I think one function of sort of the artificial
intelligence doomsday, sort of, part of our culture right now, is it's sort of our immune
response to knowing that's coming and we're over scaring ourselves, so we try to act more
quickly, which is good. But I just, you know, it's
about the words that we use versus the actual things
happening behind the words. I think one thing that's good is when people are talking
about things different ways, it makes us think about them. And also when things are
existentially threatening, we wanna pay attention to those. But the ways that they're
existentially threatening, and the ways that we're
experiencing existential trauma, I don't think that we're
really gonna understand for another century or two, if ever. And I certainly think they're not the way that we're describing them now. - Well, creating existential trauma is one of the things that
makes life fun, I guess. - Yeah, it's just what we
do to ourselves. (laughs) - It gives us really exciting,
big problems to solve. - Yeah, for sure.
- Do you think we'll see these AI systems become conscious, or convince us that they're conscious, and then maybe we'll have
relationships with them? Romantic relationships? - Well, I think people are gonna have romantic relationships with them, and I also think that some people would be convinced already that they're conscious. But I think in order... You know, what does it
take to convince people that something is conscious? I think that we actually
have to have an idea of what we're talking about, that we have to have a theory that explains when things
are conscious or not, that's testable, right? And we don't have one right now. So I think until we have that, it's always gonna be
this sort of gray area, where some people think it hasn't, and some people think it doesn't, because we don't actually know what we're talking about
that we think it has. - So do you think it's possible
to get out of the gray area and really have a formal
test for consciousness? - For sure.
- And for life, as you were- - For sure.
- As we've been talking about for assembly theory? - [Sara] Yeah. - Consciousness is a tricky one. - It is a tricky one. I mean, that's why it's
called the hard problem of consciousness, because it's hard. And you know, it might even be outside of the purview of science, which means that we can't understand it in a scientific way. There might be other ways
of coming to understand it, but those may not be the ones that we necessarily want
for technological utility, or for developing laws with respect to, because the laws are, you know, the things that are gonna
govern the technology. - Well I think that's actually where the hard problem of consciousness, a different hard problem
of consciousness is that, I fear that humans will resist. That's the last thing they will resist, is calling something else conscious. - Oh, that's interesting. I think it depends on the culture though, because I mean, some
cultures already think like everything's imbued with,
you know, a life essence or a kind of conscious. - I don't think those
cultures have nuclear weapons. - No, they don't, and they're probably not building the most advanced technologies. - The cultures that are primed for destroying the other, constructing a very
effective propaganda machine of what the other is, the group to hate, are the cultures that I worry would- - Yeah, I know.
- Would be very resistant to label something, and to sort of acknowledge
the consciousness laden in a thing that
was created by us humans. - And so what do you
think the risks are there? That the conscious things
will get angry with us and fight back? - No, that we would torture and kill conscious beings. - Oh yeah. I think we do that quite
a lot anyway, without... I mean it goes back to your... And I don't know how to feel about this, but you know, like we talked already about the predator prey thing that like, in some sense, you know, being alive requires eating
other things that are alive. And even if you're a vegetarian or you know, like try to have like... Like you're still eating
living things, yeah. - So maybe part of the story of Earth will involve a predator
prey dynamic between humans- - That struggle for existence.
- And human creations. - Yeah.
- And all of that is part of the technosphere.
- But I don't like thinking about them as like, our technologies as a separate species. 'Cause this again goes
back to this sort of levels of selection issue. And you know, if you think
about humans individually alive, you miss the fact that
societies are also alive. And so I think about it
much more in the sense of... An ecosystem's not the right word, but we don't have the right words for these things of like... And this is why I talk
about the technosphere, it's a system that is both
human and technological. It's not human or technological. And so this is the part that
I think we are really good for the like... And this is driving in part a lot of the sort of attitude of like, "I'll kill you first
with my nuclear weapons." We're really good at
identifying things as other, we're not really good at
understanding when we're the same, or when we're part of an integrated system that's actually functioning together in some kind of cohesive way. So even if you look at like, you know, the division in American politics
or something, for example, it's important that there's multiple sides that are arguing with each other, because that's actually how
you resolve society's issues. It's not like a bad feature. I think like some of the
sort of extreme positions and like the way people talk
about it are maybe not ideal, but that's how societies solve problems. What it looks like for an individual is really different than
the societal level outcomes. And the fact that like, there is... I don't wanna call it
cognition or computation, I don't know what you call it, but like there is a process playing out in the dynamics of societies, that we are all individual actors in, and like, we're not part of that. You know, like it requires
all of us acting individually, but like this higher level structure is playing out some things, and like things are getting solved for it to be able to maintain itself. And that's the level that
our technologies live at. They don't live at our level, they live at the societal level, and they're deeply integrated
with the social organism, if you wanna call it that. And so I really get upset
when people talk about the species of artificial intelligence. I'm like, "You mean we
live in an ecosystem of all these kind of intelligent things and these animating technologies
that we're, you know, in some sense helping to come alive. We are generating them, but it's not like the biosphere eliminated all of its past history when it invented a new species." All of these things get scaffolded, and we're also augmenting ourselves at the same time that we're
building technologies. I don't think we can anticipate what that system's gonna look like. - So in some fundamental way, you always want to be
thinking about the planet as one organism. - The planet is one living thing. - What happens when it
becomes multi-planetary? Is it still just the- - Still the same causal chain.
- Same causal chain. - It's like when the
first cell split into two. That's what I was talking about. When a planet reproduces itself, the technosphere emerges
enough understanding. It's like this recursive... Like the entire history of
life is just recursion, right? So you have an original life event. It evolves for 4 billion
years, at least on our planet. It evolves the technosphere, the technologies themselves
start to become... Having this property we call life, which is the phase we're undergoing now. It solves the origin of itself, and then it figures out
how that process all works, understands how to make more life, and then can copy itself
onto another planet. So the whole structure
can reproduce itself. And so the origin of life
is happening again right now on this planet in the technosphere, with the way that our planet is undergoing another transition. Just like at the origin of life when geochemistry can
transition to biology, which is the global... For me, it was a planetary
scale transition. It was a multi-scale thing, that happened from the scale of chemistry, all the way to planetary cycles. It's happening now, all the way from individual
humans to the internet, which is a global technology, and all the other things. Like there's this multi-scale
process that's happening and transitioning us globally. And it is really like
a dramatic transition. It's happening really fast. - And you think-
- And we're living in it. - You think this
technosphere that we created, this increasingly complex technosphere will spread to other planets. It'll just be-
- I hope so. I think so - You think we'll become a type
two Kardashev civilization? - I don't really like the Kardashev scale, and it goes back to like, I don't like a lot of the
narratives about life, 'cause they're very like, you
know, survival of the fittest, energy consuming this,
that and the other thing. It's very like, I don't
know, sort of old world, you know, like conqueror mentality. - What's the alternative to that exactly? - I mean, I think it does require life to use new energy sources in
order to expand the way it is. So that part's accurate. But I think this sort of process of life like being the mechanism that the universe
creatively expresses itself, generates novelty, explores the space of the possible, is really the thing that's
most deeply intrinsic to life. And so, you know, these sort of energy consuming scales of technology, I think is missing the
sort of actual feature that's most prominent about any alien life that we might find, which is that it's literally our universe, our reality, trying to
creatively express itself, and trying to find out what can exist and trying to make it exist. - See but past a certain level
of complexity, unfortunately, maybe you can correct
me, but we're built... All complex life on Earth is built on a foundation of
that predator prey dynamic. - Yes.
- And so like, I don't know if we can escape that. I don't know-
- No, we can't. But this is why I'm okay with having a finite lifetime. And, you know, one of the reasons I'm okay with that, actually-
- Yeah. - Goes back to this issue of the fact that we're resource bound. We live in a... You know, like we have a
finite amount of material, whatever way you wanna define material. I think like for me, you
know, material is time, material is information, but we have a finite amount of material. If time is a generating mechanism, it's always gonna be finite, because the universe is, you know, like it's a resource
that's getting generated, but it has a size. Which means that all the
things that could exist don't exist, and in fact, most of them never will. So death is a way to
make room in the universe for other things to exist that wouldn't be able to exist otherwise. So if the universe, over
its entire temporal history, wants to maximize the number of things... Wants is a hard word, maximize is a hard word, all
these things are approximate, but wants to maximize the
number of things that can exist, the best way to do it is to make recursively embedded
stacked objects like us, that have a lot of structure
and a small volume of space. And to have those things
turn over rapidly, so you can create as
many of them as possible. - So there for sure is a bunch of those kinds of
things throughout the universe. - Hopefully. Hopefully our universe
is teaming with life. - This is like early on in
the conversation you mentioned that we really don't understand much. Like there's mystery all around us. - Yes.
- If you had to like bet money on it, like what percent? So like say a million years from now, the story of science
and human understanding that started on Earth, is written. Like, what chapter are we on? Is this like 1%, 10%, 20%, 50%, 90%? How much do we understand? Like the big stuff? Not like the details of like... Like big important questions- - Yeah.
- And ideas. - I think we're in our twenties and- - 20% of the 20?
- No, like age-wise. Let's say we're in our twenties, but the lifespan is gonna
keep getting longer. - You can't do that.
- I can. You know why I use that though? I'll tell you why. Why my brain went there, is because you know, anybody that gets an education in physics, you know, has this sort of trope about how all the great
physicists did their best work in their twenties, and then you don't do
any good work after that. And I always thought it was kind of funny, because for me physics is not complete, it's not nearly complete, but most physicists
think that we understand most of the structure of reality. And so I think I... Actually, I think I put
this in the book somewhere, but like this idea to me that societies would discover
everything while they're young is very consistent with the way we talk
about physics right now. But I don't think that's actually the way that things are gonna go, and you're finding that people that are making major discoveries are getting older in some
sense than they were, and our lifespan is also increasing. So I think there is something about age and your ability to learn, and how much of the world you can see, that's really important
over a human lifespan, but also over the lifespan of societies. And so I don't know how
big the frontier is, I don't actually think it has a limit. I don't believe in infinity
as a physical thing, but I think as a receding horizon, I think because the
universe is getting bigger, you can never know all of it. - Well, I think it's about 1.7%. - 1.7, where does that come from? - And it's a finite... I don't know, I just made it up. But it's like-
- That number had to come from somewhere. - I think seven is the thing
that people usually pick - 7%?
- So I wanted to say 1%, but I thought it would be funnier- - Yeah, I see.
- To add a point, you know, so inject a
little humor in there. So the seven is for the humor, one is for how much mystery
I think there is out there. - 99% mystery, 1% known? - In terms of like really
big important questions. - Yeah.
- It's like, the list... Say there's gonna be like 200 chapters, like the stuff that's gonna remain true. - But you think the
book has a finite size? - Yeah, yeah.
- And I don't. I mean, not that I believe in infinities, but I think the size
of the book is growing. - Well, the fact that the
size of the book is growing is one of the chapters in the book. - Oh, there you go. Oh, we're being recursive. (laughs) - I think you have to, you
can't have an ever growing book. - Yes, you can.
- I mean you just... I mean, I don't even... Because then-
- Well, you couldn't have been asking this at the origin of life, right? Because obviously, like you wouldn't have
existed at the origin of life. - Right.
- But like the question of intelligence and artificial general... Like those questions did not exist then. And they in part existed because the universe invented
a space for those questions to exist through evolution. - But like, I think that
question will still stand a thousand years from now. - It will, but there
will be other questions we can't anticipate now,
that we'll be asking. - Yeah, and maybe we'll
develop the kinds of languages that'll be able to ask
much better questions. - Right, or like the theory of
like gravitation for example. Like when we invented that theory, like we only knew about the planets in our solar system, right? And now, you know, many centuries later, we know about all these planets around other stars and black holes, and other things that we
could never have anticipated. And then we can ask questions about them. You know, like we
wouldn't have been asking about singularities and like, can they really be physical
things in the universe several hundred years ago
that question couldn't exist. - Yeah, but it's not... I still think those are
chapters in the book. Like I don't get a sense from that. - So do you think the universe has an end? If you think it's a book with an end? - I think the number of
words required to describe how the universe works has an end, yes. (Lex laughs) Meaning like, I don't care
if it's infinite or not. - Right.
- As long as the explanation is simple and it exists. - Oh, I see. - And I think there is
a finite explanation for each aspect of it. The consciousness, the life. - Yeah.
- I mean very probably, there's like some... The black hole thing is
like, what's going on there? - Oh, I know.
- Where's that going? Like what are they... What? And then you know, why the Big Bang? Like what-
- Right. - It's probably, there's just
a huge number of universes and it's like, universes inside universes-
- You think so? I think universes inside
universes is maybe possible. - I just think it's... Every time we assume this is all there is, it turns out there's much more. - The universe is a huge place - And we mostly talked about the past and the richness of the past. But the future, I mean with
many worlds interpretation of quantum mechanics, so- - Oh, I'm not a many worlds person. - You're not?
- No. Are you? How many Lexes are there? - Depending on the day. Well-
- Do some of them wear yellow jackets? - At the moment you asked the question, there was one. At the moment I'm answering it, there's now near infinity, apparently. I mean the future is
bigger than the past, yes? - Yes.
- Okay, well there you go. And the past, according to
you, it's already gigantic. - Yeah, but yeah, I mean that's consistent
with many worlds, right? 'Cause like there's this
constant branching, so. But it doesn't really have
a directionality to it. I don't know, many worlds is weird. So my interpretation of reality is like if you folded up like all that bifurcation of many worlds, and you just fold it into
the structure that is you, and you just said, you are
all of those many worlds and like that sort of, you
know, like your history, like converged on you. But like you're actually... An object exists that's like... That you know, was selected to exist, and you're self-consistent
with the other structures. So like the quantum mechanical reality is not the one that you live in. It's this very deterministic,
classical world and you're carving a
path through that space. But I don't think that
you're constantly branching into new spaces. I think you are that space. - Wait, so to you at, at the
bottom it's deterministic. I thought you said the universe- - No, it's random at the bottom, right? But like this randomness that we see at the bottom of reality,
that is quantum mechanics, I think like people have
assumed that is reality. And what I'm saying is like all those things you see in many worlds, all those versions of you, just collect them up and bundle them up, and like they're all you. And what has happened is, you know, like elementary particles don't have... They don't live in a
deterministic universe, the things that we study
in quantum experiments, they live in this fuzzy random space. But as that structure collapsed and started to build structures
that were deterministic and evolved into you, you are a very deterministic,
macroscopic object. And you can look down on that universe that doesn't have time in
it, that random structure. And you can see that all
of these possibilities look possible, but they don't look... They're not possible for you, because you're constrained by this giant like causal structural history. So you can't live in all those universes. You'd have to go all the way back to the very beginning of the universe, and retrace everything
again to be a different you. - So where's the source of the free will for the macro object? - It's the fact that you're
deterministic structure living in a random background, and also, all of that
selection bundled in you, allows you to select on possible futures. So that's where your will comes from, and there's just always a
little bit of randomness because the universe is getting bigger and you know, like this idea that the past and the present
is not large enough yet to contain the future. The extra structure has
to come from somewhere. And some of that is because, outside of those giant causal structures that are things like us, it's fucking random out there, (both laugh) and it's scary, and we're all hanging onto each other, because the only way to
hang onto each other, like the only way to exist, is to like clinging on to all of these causal structures that we happen to
co-inhabitate existence with, and try to keep reinforcing
each other's existence. - All the selection bundled in. - But free will's totally
consistent with that. - I don't know what I think about that. That's complicated to imagine. Just that little bit of
randomness is enough. Okay. - Well it's also... It's not just the randomness. There's two features. One is, the randomness helps generate some novelty and some flexibility. But it's also that like, because you're the structure
that's deep in time, you have this combinatorial
history that's you, and I think about time
and assembly theory, not as linear time, but as combinatorial time. So if you have all of the structure that you're built out of, you in principle, you know, your future can be
combinations of that structure. You obviously need to persist
yourself as a coherent you, so you wanna optimize for a common, like a future in that combinatorial space that still includes you, most of the time for most of us. And when you make those kinds... And then that gives you
a space to operate in, and that's your sort of horizon where your free will can operate, and your free will can't be instantaneous. So for like example, like I'm sitting here
talking to you right now, I can't be in the UK and
I can't be in Arizona, but I could plan, I could
execute my free will over time, because free will is a
temporal feature of life, to be there, you know,
tomorrow or the next day if I wanted to. - But what about like the
instantaneous decisions you're making? Like to, I don't know... To put your hand on the table, that's- - I think those were
already decided a while ago. I don't think that the... I don't think free will
is ever instantaneous, - But on a longer time horizon- - Yep.
- There's some kind of steering going on?
- Mm-hmm. And who's doing the steering? - You are.
- Hmm. And you being this macro
object that encompasses- - Or you being Lex. (laughs) Whatever you wanna call it. (laughs) - There you are, assigning
words to things once again. - I know.
- Why does anything exist at all? - Ugh, I don't know.
- You've kind of taken that as a starting point. - Yeah.
- That it exists. - I think that's the hardest question. - Isn't it just hard questions
stacked on top of each other? - It is.
- Wouldn't it be the same kind of question
of, what is life? It is the same. Well that's sort of like, I try to fold all of the
questions into that question, 'cause I think that one's really hard, and I think the nature of
existence is really hard. - You think actually like
answering, what is life? Will help us understand existence? Maybe it's turtles all the way down and it'll just... Understanding the nature of turtles will help us kind of march down even if we don't have the
experimental methodology of reaching before the Big Bang. - Right. So, well I think there's
sort of two questions embedded here. I think the one that we can't
answer by answering life is, why certain things exist and others don't. But I think the sort of ultimate question, the sort of like prime mover question of why anything exists, we will not be able to answer. - What's outside the universe? - Oh, there's nothing
outside the universe. So I am a very, like... I am like the most physicalist
that like anyone could be. So like for me, everything
exists in our universe and I like to like think it like, everything exists here. So even when we talk about
the multiverse, I don't... Like, to me it's not like
there's all these other universes outside of our universe that exists. The multiverse is a concept
that exists in human minds here, and it allows us to have
some counterfactual reasoning to reason about our own cosmology, and therefore it's causal in our biosphere to understanding the
reality that we live in, and building better theories. But I don't think that the
multiverse is something like... And also math. Like I don't think
there's a platonic world that mathematical things live in. I think mathematical things
are here on this planet. Like I don't think it makes
sense to talk about things that exist outside of the universe. If you're talking about them, you're already talking
about something that exists inside the universe, and
is part of the universe, and is part of like what
the universe is building. - It all originates here. It all exists here in some- - I mean, what else would there be? - There could be things you
can't possibly understand outside of all of this
that we call the universe. - And you can say that, and that's an interesting philosophy, but again, this is sort of
like pushing on the boundaries of like the way that we understand things. I think it's more constructive to say the fact that I can
talk about those things is telling me something about the structure of
where I actually live and where I exist.
- Just because it's more constructive
doesn't mean it's true. - Well, it may not be true. It may be something that allows
me to build better theories I can test, to try to
understand something objective. - And in the end, that's a
good way to get to the truth. - Exactly.
- Even if you realize- - So I can't do experiments-
- You were wrong in the past. - Yeah. So there's no such thing
as experimental Platonism, but if you think math is an object that emerged in our biosphere, you can start experimenting
with that idea. And that to me is really interesting. Like to think about... Well people, I mean, mathematicians do think about math sometimes
as an experimental science, but to think about math
itself as a object for study by physicists, rather than a tool physicists
used to describe reality, it becomes the part of reality
they're trying to describe, to me is a deeply interesting inversion. - What to you is most beautiful about this kind of exploration
of the physics of life that you've been doing? - I love the way it makes me feel. - And then you have to try to convert the feelings into visuals and the visuals into words?
- Yeah. So I think I love... Yeah, I love the way it
makes me feel to have ideas that I think are novel. And I think that the dual side of that is the painful process of
trying to communicate that with other human beings, to test if they have any
kind of reality to them. And I also love that process. I love trying to figure out how to explain really
deep, abstract things that I don't think that we understand, and trying to understand
them with other people. And I also love the shock value of you... Like this kind of idea we
were talking about before, of like being on the boundary
of like what we understand, and so people can kind of
see what you're seeing, but they haven't ever
saw it that way before. And I love the shock value
that like people have, like that immediate moment of recognizing that there's something beyond the way that they thought about things before. And being able to deliver that to people, I think is one of the biggest joys that I have, it's just like... And maybe it's that sense of mystery, like to share that there's something beyond the frontier of how we understand, and we might be able to see it. - And you get to see
the humans transformed- - Yeah.
- Like a new idea? - Yes. And I think my greatest wish in life is to somehow contribute to an idea that transforms the way that we think. Like, you know, I have
my problem I wanna solve, but like the thing that
gives me joy about it is really changing something, and ideally getting to
a deeper understanding of how the world works and what we are. - Yeah, I would say understanding
life at a deep level- - Yeah.
- Is probably one of the most exciting problems. One of the most exciting questions. So I'm glad you are trying
to answer just that, and doing it in style. (Sara laughs) - It's the only way to do anything. - Thank you so much for
this amazing conversation. Thank you for being you,
Sara. This was awesome. - Thanks, Lex. - Thanks for listening to this conversation with Sara Walker. To support this podcast, please check out our
sponsors in the description. And now, let me leave you with some words from Charles Darwin. "In the long history of
humankind and animal kind too, those who learned to collaborate and improvise most
effectively, have prevailed." Thank you for listening, and
hope to see you next time.