Kind: captions
Language: en
the following is a conversation with
sarah walker a nestor biologist and
theoretical physicist at arizona state
university and the santa fe institute
she's interested in the origin of life
how to find life on other worlds and in
general the more fundamental question of
what even life is
she seeks to discover the universal laws
that describe living systems on earth
and elsewhere using physics biology and
computation
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this is the lex friedman podcast and
here is my conversation with sarah
walker
how did life originate on earth what are
the various hypotheses for how life
originated on earth yeah so
i guess you're asking a historical
question which is always a good place to
start thinking about life um
so there's a lot of ideas about how life
started on earth um probably the most
popular is what's called the rna world
scenario um so this idea is probably the
one that you'll see most reported in the
news
and is based on the idea that there are
um
molecules in our bodies um that uh relay
genetic information and we know those as
dna obviously but there's also sort of
an intermediary called rna ribonucleic
acid
that also plays the role of proteins
and
people came up with this idea in the 80s
that maybe that was the first genetic
material because it could play both
roles of being genetic and performing
catalysis and then somehow that idea got
reduced to this idea that there was a
molecule that emerged on early earth and
underwent darwinian evolution and that
was the start of life
so there's a lot of assumptions
packed in there that we could unpack but
that's sort of the leading hypothesis
there's also other ideas about life
starting as metabolism and so that's
more connected to the geochemistry of
early earth
and it would be kind of more focused on
this idea that you get some kind of
catalytic cycle of molecules that can
reproduce themselves and form some kind
of metabolism and then life starts
basically as self-organization and then
you have to explain how evolution comes
later
right so that's the difference between
sort of uh energy and genetic code so
like energy and information are those
are the two kind of yeah
yeah i think that's a good way of
putting that it's um
it's kind of funny because i think most
of the people that think about these
things are really disciplinary bias so
the people that tend to think about
genetics come from a biology background
and they're really evolution focused and
so they're worried about where does the
information come from and how does it
change over time but they're talking
about information in a really narrow way
where they're talking about a genetic
sequence and then most of people that
think about
metabolism origins of life scenarios
tend to be people like physicists or
geochemists that are worried about what
are the energy sources and what you know
like what kinds of organization can you
get out of those energy sources okay so
which one is your favorite i don't like
either
okay all right can we talk about them
for a little bit longer though
uh so okay so there's uh early earth
what was that like was there just mostly
covered by oceans was there heat sources
energy sources so if we
uh talk about the metabolism view of the
origin of life like where was the source
of energy probably the most popular view
for where the original life happened on
earth is hydrothermal vents because they
had sufficient energy
and so we don't really know a lot about
early earth
we have you know some ideas about when
oceans first formed and things like that
but the time of the original life is
kind of
um not well understood or pinned down
and the conditions on earth at that time
are not well known
but a lot of people do think that there
was probably hydrothermal vents which
are really hot
chemically active regions say on the sea
floor in modern times which also would
have been present on early earth and
they would have provided energy and
organics
and basically all of the right
conditions for
the origins of life which is one of the
reasons that we look for these
hydrothermal systems when we're talking
about life elsewhere too
okay and for the genetic code
the idea is that the rna is the first
like why would rna
be the first moment you can say it's
life
i guess the idea is it could both
have persistent information
and then it can also do some of the work
of like what creating a self-sustaining
organism
yeah that's the basic idea so the idea
is you have in an rna molecule you have
a sequence of characters say so you can
treat it like a string in a computer
and it can be copied so information can
be propagated
which is important for
evolution because evolution happens by
having inheritance of information so for
example you know like my eyes are brown
because my mother's eyes were brown
so you need that copying of information
but then
you
also have the ability to perform
catalysis which means that that rna
molecule is not inert in that
environment but it actually interacts
with something that could potentially
mediate say a metabolism that could then
fuel
the actual reproduction of that molecule
so
in some ways
people think that rna gives you
you know
the most bang for your buck in a single
molecule and therefore
you know it gives you all the features
that you might think are life um
and so that this is sort of where this
rna world conjecture came from is
because of those two properties
isn't it amazing that rna came to be
in general isn't it yes that is amazing
okay so we're not talking down about rna
no no i love rna it's one of my favorite
molecules i think it's beautiful it's
just not step one
yeah i think i think the issue it's not
even the rna world is a problem and
actually if you really um dig into it
the rna world is not one hypothesis it
is a set of hypothesis
hypotheses sorry and they range from
a
molecule of rna spontaneously emerged on
the early earth and started evolving
which is kind of like the hardest rna
world scenario which is the one i cited
and i get a little um
uh animated about because it seems so
blatantly wrong to me but that's a
separate story and then the other one is
actually something i agree with which is
that
you can say there was an rna world
because rna was the first genetic
material for life on earth so an rna
world could just be
the earliest organisms that had
genetics in a modern sense didn't have
dna evolved yet they had rna
right and so that's sort of a softer rna
world scenario in the sense that it
doesn't mean it was the first thing that
happened
but it was a thing that definitely
was part of the lineage of events that
led to us
so if life was a
like a best of album it would be on the
maybe one of the songs on there yes one
of the early songs okay it's on the
greatest hits greatest hits that's the
word i was looking for okay did life do
you think originate once
twice three times on earth multiple
times what do you think i think that's a
really difficult question um and an
important question it's a super
important question no that no it's a
really important question um and so
there there's some so there's
there's a lot of questions in that
question um so one of the first ones
that i think needs to be addressed is is
the original life a continuous process
on our planet so
we think about the original life is
something that happened on earth um say
almost four billion years ago because we
have evidence of life emerging very
early on our planet
um
and then an original life event quote
unquote a singular event whatever that
was happened and then all life on earth
that we know
is a descendant of that particular event
in our universe right and so
um but
uh we don't have um
any idea one way or the other if the
original life is happening repeatedly
and maybe it's just not taking off
because life is already established
that's a argument that people will make
or
maybe there are alternative forms of
life on earth that we don't even
recognize
um so this is the idea of a shadow
biosphere that there actually might just
be completely other life on earth but
it's so alien that we don't even know
what it is
i'm gonna have to talk to you about the
shadow biosphere
in a second but first let me ask for the
other alternative which is panspermia
right so that's the idea the hypothesis
that life exists elsewhere in the
universe and got to us through like an
asteroid
or a planetoid or some
uh according to wikipedia space dust
whatever the heck that is
uh it sounds fun but basically rode
along
yeah whatever
kind of rock and got to us
do you think that's at all a possibility
sure so i think the reason that most
original life scientists are interested
in the origin of life on earth and say
not the original life
um
you know on mars and then panspermia you
know the exchange of life between
planets being the explanation is once
you start removing the original life
from earth you know even less about it
than you do if you study it on earth
although i think there are ways of
reformulating the problem this is why i
said earlier like oh you mean the
historical original life problem you
don't mean the problem of how does life
arise in the universe and what the
universal principles are because there's
this historic problem how did it happen
on early earth and there's a more
tractable general problem of how does it
happen
and how does it happen is something we
can actually ask in the lab how does it
how did it how did it happen on early
earth is
a much more detailed and nuanced
question and requires detailed knowledge
of what was happening on early earth
that we don't have
and i'm personally more interested in
general mechanisms so to me it doesn't
matter if it happened on earth or it
happened on mars
it just matters that it happened we have
evidence that happened
the question is did it happen more than
once in our universe and so the reason i
don't find panspermia as a particularly
i think it's a fascinating um hypothesis
i definitely think it's possible um and
um
and i in particular i think it's
possible once you get to the stage of a
life where you have technology because
then you you obviously can spread out
into the cosmos um but it's also
possible for microbes because we know
that um certain microorganisms can
survive the journey in space and we you
know they can live in a rock and go
between mars and earth like people have
done experiments to try to prove that
could work um so in that scenario it's
super cool because then you get
planetary exchange but say we go find we
go look for life on mars and it ends up
being exactly the same life we have on
earth biochemically speaking then we
haven't really discovered something new
about the universe what kind of aliens
are possible were there other original
life events if we find if all the life
we ever find is the same original life
event in the universe it doesn't help me
solve my problem but it's possible that
that would be a sign that you could
separate the environment from the
basic ingredients yes so that's true you
can have like a life gun
that you shoot throughout the universe
and then uh
like once you shoot it it's like the
simpsons with a makeup gun that was a
great episode uh when you shoot this
life gun
it'll he'll find the earth's it'll like
get sticky it'll stick to the earth's
and that kind of reduces the barrier of
uh
like the time it takes the the luck it
takes to actually from nothing from the
basic chemistry from the basic physics
the universe for the life to spring up
yeah i think this is actually super
important to just think about like does
life
getting seated on a planet have to be
geochemically compatible with that
planet so you're suggesting like we
could just shoot guns in space and like
life could go to mars and then it would
just live there and be happy there um
but that's actually an open question so
one of the things i was going to say in
response to your question about
whether the original life happened once
or multiple times is for me personally
right now in my thinking although this
changes on a weekly basis but um is that
i think of life more as a planetary
phenomena so i think the original life
because um because life is so
um intimately tied to planetary cycles
and planetary processes and this goes
all the way back through the history of
our planet that the original life itself
grew out of geochemistry and became
coupled and controlled geochemistry and
and when we start to talk about life
existing on the planet is when we have
evidence of life
actually influencing properties of the
planet um and so
so if life is a planetary property um
then going to mars is not a trivial
thing because you basically have to make
ours
mars more earth-like um and so in some
sense um like when i think about sort of
long-term vision of humans in space for
example
really what you're talking about when
you're saying let's send our
civilization to mars is you're not
saying let's send our civilization to
mars you're saying let's reproduce our
planet on mars like the information from
our planet actually has to go to mars
and make mars more earth-like which
means that you're now having a
reproduction process like a cell
reproduces itself to propagate
information in the future
planets have to figure out how to
reproduce their conditions including
geochemical conditions on other planets
in order to actually reproduce life in
the universe which is kind of a little
bit radical but i think
for long-term sustainability of life on
a planet that's absolutely essential
okay so
if we were to think about life as a
planetary phenomenon
and so life on mars would be best if
it's way different than life on earth
we have to ask the very basic question
of
what
is life
i actually don't think that's the right
question to ask
it took me a long time to get there
right so cross it out yeah you cross it
off your list it's wrong
no question um no no no i mean i think
it has an answer but i think the part of
the problem is um you know most of the
places in science where we get really
stuck is because we don't know what
questions to ask um and so you can't
answer a question if you're asking the
wrong question um and i think uh the way
i think about it is obviously i'm
interested in what life is so i'm being
a little cheeky when i say that's the
wrong question to ask that's exactly
like the question that's like the core
of my existence but
um
but i think the way of framing that is
what is it about our universe that
allows features that we associate life
to be there um and so really what i
guess when i'm asking that question what
i'm after is an explanatory framework
for what life is right and so most
people they try to go in and define life
and they say well life is uh say a
self-reproducing chemical system capable
of darwinian evolution that's a very
popular definition for life um or life
is something that metabolizes and eats
that is not how i think about life what
i think about life is there are
principles and laws that govern our
universe
that we don't understand yet
that have something to do with
how information interacts with the
physical world i don't know exactly what
i mean even when i say that um because
we don't know these rules um but it's a
little bit like um i like to use
analogies you'll give me time to be like
a little long-winded for a second even
in as i um but um but sort of like if
you look at the history of physics for
example this is like so we are in the
period of the development of
thought on our planet where we don't
understand what we are yet right um
there was a period of thought in the
history of our planet where we didn't
understand what gravity was
um and we didn't understand for example
that planets in the heavens
you know were actually planets or that
they operated by the same laws that we
did
um and so there has been this sort of
progression of getting a deeper
understanding of explaining basic
phenomena like i'm not gonna drop the
cup i'll drop the water bottle there you
go okay that fell right but why did that
fall um
this is why i'm a theorist not an
experiment
i could have gone wrong in so many ways
i know i could have especially if i did
the confidence smash anyway
um so um so if you think you take this
view that there's sort of some missing
principles i associate them uh to
information and what it what the sort of
feeling there is there's some missing
explanatory framework for how our
universe works and if we understood that
physics it would explain what we are um
it might also explain a lot of other
features we don't associate to life um
and so it's a little like um people
accept the fact that gravity is a
universal phenomena but when we want to
study gravity we study things like large
scale
you know galactic structures or black
holes or planets
if we want to understand information and
how it operates in the physical world we
study intelligent systems or living
systems because they are the
manifestation of that physics
and the fact that we can't see that
clearly yet or we don't have that
explanatory framework i think it's just
because we haven't been thinking about
the problem deeply enough but i feel
like if you're explaining something
you're deriving it from some more
fundamental property and of course
um i have to say i'm wearing my my
physicist hat so i have a huge bias of
liking
simple elegant explanations of the
universe that
um
you know really are compelling but i
think one of the things that i've sort
of
maybe in some ways rejected my training
as a physicist is that most of the
elegant explanations that we have so far
don't include us in the universe and i
can't help but think there's something
really special about what we are and
there have to be some deep principles at
play there
um
and so so that's sort of my perspective
on it now when you ask me what life is i
have some ideas of what i think it is
but i think that we haven't
gotten there yet because we haven't been
able to see that structure and it's and
just go back to the gravity example it's
a little like you know in ancient times
they didn't know i was talking about
stars and heavens and things they didn't
know those were um you know governed by
the same principles as that starting to
experiment here's where i was going with
it once you realize like newton did that
you know heavenly emotions and earthly
emotions are governed by the same
principles and you unify terrestrial and
celestial motion you get these more
powerful ideas
um and i i think where life is is
somehow unifying these abstract ideas of
computation and information
with the physical world with matter and
realizing that there's some explanatory
framework that's not physics and it's
not computation but it's something
that's deeper
so
answering the question of what is life
requires
deeply understanding something about the
universe as information processing
universe is computation
something about
like would uh once you come up with an
answer to what is life well the words
information and computation be in the
paragraph no i don't think so oh damn it
okay i know it doesn't help does it i
know i i hate actually i hate this about
what i do because it's so hard to
communicate right with words like when
you have words that are
um ideas that have historically
described one thing and you're trying to
describe something people haven't seen
yet right and the words just don't fit
so what uh what's wrong is it too
ambiguous the word information we could
switch to binary if you want yeah no i
don't think it's binary either i think
information is just loaded i use it so
the other way i might talk about it is
the physics of causation but i think
that's worse because causation is even
more loaded word than
um
information causation is fundamental you
think i do yeah and um in some sense i
think the physics so this is the really
radical part some sense like when i
really think about it sort of most
deeply uh what i think life is is
actually the physics of existence what
gets to exist and why um and you know
for simple elementary particles that's
not very complicated because the
interactions are simple but for things
like um you know you and me and human
civilizations
um you know what comes next in the
universe is really dependent on what
came before and there's a huge space of
possibilities of things that can exist
and when i say information and causation
what i mean is why is it that
cups evolved in the universe and not
some other object that could deliver
water and not spill it
i don't know what you would call it uh
maybe it wouldn't be a cup but um but
it's a huge it it's um
you know you know people talk about the
space of things that could exist as
being actually infinitely large right i
don't know if i believe in infinity
um but i do think that
there is something very interesting
about
the problem of what exists in its
relationship to life so do you think
this
the set of things that could exist is
finite
it's very large but like if we were to
think
about the physics of existence
like how how many shapes of mugs can
there be like is uh
in the initial programming i should go
to the math department for that but
so that's not a topology question i just
mean
maybe another way to ask is what do you
think is fundamental to the universe and
what is emergent so if existence i was
supposed to think of that as somehow
fundamental you think so there's a
couple problems in physics that i think
this is related to one is why does
mathematics work at describing reality
so well
um and then there is this problem of we
don't understand why the laws of physics
are the way they are or why certain
things get to exist or
what put in place the initial condition
of our universe right there's all of
these sort of really deep and big
problems and they they all um
indirectly are related i think to the
same kind of thing that um
you know our physics is really good if
you specify the initial condition at
specifying a certain sequence of events
but it doesn't deal with the fact that
other things could have happened which
is kind of an informational property
like a counter factual property
um
and it's not good at explaining
uh
you know this conversation right now
it's just it there are certain things
that are outside the explanatory reach
of current physics and
um i think they require looking at it
from a completely different direction
um and so i don't want to have to
fine-tune the initial condition of the
universe to specify precisely all the
information in this conversation i think
that's a ridiculous assertion um but
that's sort of like how people want to
frame it when they talk about
um
you know the standard model is
sufficient if we had computing power to
basically explain all life in our
existence an interesting thing you said
is the way we think about information
computation is by observing a particular
kind of systems on earth
that exhibit something we think of as
intelligence but that's
that's like uh looking at i guess the
tip of an iceberg and we should be
really looking at the fundamentals of
like the iceberg like like like what
makes
water and ice and and and the chemistry
that from which intelligence emerges
essentially
we can't just couple the information
from the physics and i think that's what
we've gotten really good at doing
especially with
sort of
the modern age where you know software
is so abstracted
um from
hardware
but the entire process of biological
evolution has basically been built like
been building layers of increasing
abstraction and so it's really hard to
see that physics in us but it's much
clearer to see it in molecules
yeah but i guess i'm trying to figure
out what what do you think are the best
tools to look at it
what do you think
an open mind is that a tool
what's the physics of an open mind
i think if we saw that we'll solve
everything i'm saying an open mind
because i think the biggest stumbling
block um
to understanding sort of the things i've
been trying to articulate or and when i
talk also with colleagues that are
thinking deeply about these same issues
is
none of it is inconsistent with what we
know it's just such a radically
different perception perception of the
way we understand things now that it's
hard for people to get there and in some
ways you have to almost forget what
you've learned in order to learn
something new right so i feel like most
of my career trying to understand the
problem of life has been variously
forgetting and then relearning things
that i learned in physics and and i
think you have to
you have to have a capacity
to learn things but then accept that
things that you were you you learned
might not be true
um
or
or might need refinement or reframing
um
and the best way i can say that is just
like with a physics education there are
just certain things you're told in
undergrad that are like facts about the
world
and your physics professors never tell
you that those facts actually emerge
from a human mind right so we're taught
to think about say the laws of physics
for example
as this like
autonomous thing that exists outside of
our universe and tells our universe how
it works yeah um but the laws of physics
were invented by human minds to describe
things that are regularities in our
everyday experience
right they don't exist autonomous to the
universe right so it's like turtles on
top of turtles but
eventually gets the human mind and then
you have to explain the human mind with
the turtles yes so you have to yeah it
comes from humans this understanding the
simplification of the universe these
models yeah there's a guy named stephen
wolfram there's a
concept called cellular automata so
there's a
there's some mysteries in these um
systems that are computational in nature
that have
maybe echoes
of the kind of mysteries we should
need to solve to understand what is life
[Music]
so
if we could talk take a
computational view of things do you
think there's something compelling to
reducing everything down to computation
like the universe is computation and
then trying to understand
life so
throw away the biology throw away the
chemistry throw away even the physics
that you you learn undergrad in graduate
school and more look at these simple
little systems whether it's cellular
automata or whatever the heck kind of
computational systems that operate on
simple local rules and then create
complexity
as they evolve
is is it uh at all do you think
productive to focus on those kinds of
systems to get an inkling of what is
life
and if it is
do you do you think it's
it's possible to come up with some kind
of laws and principles about what makes
life in those computational
systems
so i like cellular automata i think
they're good toy models um but mostly
like where i've thought about them and
use them is to actually
um
[Music]
let's say poke at sort of the current
conceptual framework that we have and
see where the flaws are
um so i think like the part that you're
talking about that people find
intriguing is that if you have like a
fairly simple rule
and you specify some initial condition
and you run that rule and that initial
condition you could get really complex
patterns emerging and ooh doesn't that
look lifelike um
yeah
well it's like really surprising isn't
it it is really surprising and they're
beautiful um and i i think they have a
lot of nice features associated to them
um i think the things that i find yeah
so so i i do think um as a proof of
principle that you can get complex
things emerging from simple rules
they're great
um as a sort of proof of principle about
some of the ways that we might think of
computation as being sort of a
fundamental principle for dynamical
systems and maybe the the evolution of
the universe as a whole they're a great
model system
as an explanatory framework for life i
think
they're a bit problematic for the same
reason that
the laws of physics are a bit
problematic um and the clearest way i
can articulate that is like cellular
automata are actually cast in sort of a
conceptual framework for how the
universe should be described that goes
all the way back
to newton in fact with this idea that we
can have a fixed law of motion
which exists sort of it's given to you
you know the great programmer in the sky
gave you this equation
or this rule and then you just run with
it um and the rule doesn't have so a
good feature of the rule is it doesn't
have specified in the rule information
about the patterns it generates so you
wouldn't want for example the my cup or
my water bottle or you know me sitting
here to be specified in the laws of
physics that would be ridiculous because
it wouldn't be a very simple explanation
of all things happening i'd have to
explain everything
so and tell your time to have that
feature
and the laws of physics have that
feature
um but but you know you also need to
specify the initial condition um and it
also it basically means that everything
that happens is sort of a consequence of
that initial condition and i think this
kind of framework is just not the right
one for biology um and part of the way
that it's easiest to see this is
um a lot of people talk about
self-reference being important in life
the fact that um you know like the
genome has information encoded in it
that information gets read out
um it specifies something about the
architecture of a cell
the architecture of the cell includes
the genome so the genome has basically
self-referential information
self-reference obviously comes up in
computational law because it's kind of
foundational um to turing's work and
what girdle did with the incompleteness
theorems and things so there's a lot of
parallels there and and people have
talked about that at depth um but the
other way of kind of thinking about it
in terms of like a more physics-y way of
talking about it
is that what it looks like in biology is
that the rules or the laws depend on the
state this is typical in computer
science this is obvious to you you know
the update rule depends on the state of
the machine right but and you know you
don't think about um
uh you know that being sort of the
dynamic and physics it's you know the
rules given to you and then it you know
it's a it's a very special subclass say
of computations if
you know you don't ever change the
update um but in biology it seems to be
that the state and the law change
together as a function of time and we
don't have that as a paradigm in physics
and so a lot of people talked about this
as being kind of a perplexing feature
that maybe there are certain scenarios
where the laws of physics or the laws
that govern a particular system actually
change as a function of state of that
system that's trippy so yeah the the
hope of physics it's a hope i guess but
often stated as a
underlying assumption is that the law
is uh static right
okay and even having laws that vary in
time and not even as a function of the
state is very radical
when you the time in general like yeah
you want to remove time from the
equation as much as possible yeah i i do
um there's some interesting things in
this like when we think it's sort of
deep more deeply about the actual
physics that we're trying to propose
governs life um with me with
collaborators and then also other people
that think about similar things that
time might actually be fundamental and
there really is an ordering to time
um and that events in the universe are
unique because they have a particular
you know they they happen like an object
in the universe requires a certain
history of events in order to exist
which therefore suggests that time
really does have an ordering i'm not
talking about the flow of time and our
perception of time just the ordering of
events causation yes causation there's
that word again
so causation that's when you say time
you mean causation yes
in your proposed model
of the physics of life the the
fundamental thing would be causation if
you were to bet your money on on one
particular horse or whatever yes and
then space is emergent
yes so everything's emergent except time
kind of yeah or causation
change all the time why it look like
laws are the same laws well because uh
well one way um and i actually this idea
comes from lee cronin because i work
with him very closely on these things is
that the laws of physics look the way
they do because they're low memory laws
so they don't require a lot of
information to specify them they're very
easy for the universe to implement but
if you get something like me for example
i require 4 billion year history to
exist in the universe i come with a lot
of historical baggage
and that's part of what i am as a set of
causes that exist in the universe
so i have local rules that apply to me
that are associated with sort of the
information in my history
that aren't universal to every object in
the universe
and there are some things that are very
easily easy to implement low memory
rules that apply to everything in the
universe
so there's no shortcuts to you no i so
yeah i don't believe in like things like
boltzmann brains or
uh you know fluctuations out of the
vacuum that can produce things like your
desk ornaments
i actually think they require a
particular causal chain of events to
exist
well i appreciate the togetherness of
that but uh so how does that
if we have to simulate the entire
universe to create the ornaments and the
two of us
how are we supposed to create
engineer life yeah that's not
this goes back to sort of the critique
of the rna world i think one of the
problems and i'll get to answering your
question but i think this is kind of
relevant here one of the problems with
the rna world
when we test it in the laboratory is how
much information we're putting into the
experiment
we specify the flasks we make pure
reagents we mix them we take them out we
put them in the next flask we change the
ph we change the uv light and then we
get a molecule and it's not even an rna
molecule necessarily it might just be a
base right um and so
people don't usually think about the
fact that we're agents in the universe
making that experiment and therefore we
put a little bit of life into that
experiment
um
because it's part of our biological
lineage in the same sense that a couple
or i am a part of the biological lineage
the experimental ideas
are
injecting life yes
and the constraints that we put on the
experiments because those conditions
wouldn't exist in the universe on planet
earth at that time without us as the
boundary condition right so
even though we're not actually adding
any actual like chemistry or biology
that it could be identified as life
are the constraints we're adding to the
experiment the design of the experiment
yeah you can think of a design
experiment as a program you put
information in it's an algorithmic
procedure that you design the experiment
and so um so the original life problem
becomes one of minimizing the
information we put into physics
to actually watch the spontaneous
original life can we can we have so can
is it possible in the lab to have an
information vacuum then so like if we
could we would that would be amazing i
don't know that's a good question for
more for lee yeah you guys by the way
for people who don't know lee cronin is
uh
you guys are uh colleagues and uh
i've gotten a chance to listen to the
two of you talking there's great sort of
chemistry and you're brilliant
brainstorming together and there's
there's a really exciting
community here of of brilliant people
from different disciplines working on
the problem yeah of life of complexity
of uh
i don't know whatever
the words fail us to describe the exact
problem we're trying to actually
understand here intelligence all those
kinds of things
okay so
what what uh
from a lab perspective so lee i guess
would you call him a chemist no i think
by training he's a chemist but i think
most of the people that work in the
field we do have lost their discipline
that's why i couldn't answer your
question
okay i don't know what you call them
yeah i don't know what i call myself i
don't know what i call any of my friends
so why why is it so hard to create uh
and it's an interesting question to
create biological life in the lab
like from your perspective
is that an important problem to work on
to try to recreate the historical origin
of life on earth or echoes of the
historical origin i think echoes is more
appropriate i don't think asking the
question of what was the exact
historical sequence of events and
engineering every step in the process to
make exactly the chemistry of life on
earth as we know it is a meaningful way
of asking the question and it's a little
bit like
um you know if
since you're in computer science like if
you know the answer to a problem it's
all it's easier to find a program to
specify the output right but if you
don't know the answer or priority you
know finding an algorithm for like say
finding a prime or something it's easy
to um you know
uh verify it's a prime number it's hard
to find the next prime um and uh
the way the original life is structured
right now in the historical problem is
you know the answer and you're trying to
retrodict it by breaking it down into
the set of procedures where you're
putting a lot of information in and what
we need to do is ask the question of
how is it
that the rules of how our universe is
structured permits things like life to
exist and what is the phenomena of life
and those questions are obviously
essentially the same question and so
you're looking essentially for this
missing
physics this missing explanation for
what we are and you need to set up
proper experiments that are going to
allow you to probe
the vast complexity of chemistry in an
unconstrained way with as little
information put in as possible to see
when things
when does information actually emerge
how does it emerge
what is it
and
part of the the sort of conjecture we
have is
that this physics only becomes relevant
or at least this is this is my personal
conjecture and um and it's sort of
uh validated by this kind of theory
experiment collaboration
um
that we we have working in this area
um that this you know sort of i made the
point about like gravity existing
everywhere right but when you study um
an atomic nucleus you don't care about
gravity it's not relevant physics there
right it's it's weak it doesn't matter
and so
this idea that that there's kind of a
physics associated with information
for me
it's very
evident that that physics doesn't become
relevant until you need information to
specify the existence of a particular
object and the scale of reality where
that happens is in chemistry because of
the combinatorial diversity of chemical
objects that can exist far outs
exceeds the amount of resources in our
universe so if you want to you can't
make every possible protein of length um
you know 200 amino acids there's not
enough resources so in order for this
particular protein to exist and this
protein to exist in high abundance means
that you have to have a system that has
knowledge of the existence of that
protein and can build it so existence
comes to be at the chemical level so
existence is most
uh is uh best understood at the chemical
level it's most evident
it's a little bit like nobody argues
that gravity doesn't exist in an atomic
nucleus it's just not relevant physics
there so the physics of information
is everywhere it exists at every
combinatorial scale but it becomes more
and more relevant the more set of
possibilities that could exist
because you're you're you're you have to
specify more and more about why this
thing exists and not the infinite it's
not an infinite set but you know the set
of undefined set of other things that
could exist so can ask a weird
yeah question which is
so let's look into the future
i try that every day it never works
so say a nobel prize is given in physics
maybe chemistry
for discovering the origin of life
no not but not the historical origin
some kind of thing that we're talking
about
what exactly
would
what do you think
that like what do you think that person
maybe you did to get that nobel prize
like what would they have to have done
because you could do a bunch of
experiments that go like with an aha
moment
like you rarely get the nobel prize
for like you've solved everything we're
done right it's like some inkling of
some deep truth right like what do you
think that would actually look like
would it be an experimental result
uh i mean it will have to have some kind
of experimental maybe validation
component so what would that look like
this is an excellent question
i want to
sorry i'm going to make a quick point
which is just a slight tangent but you
know like when people ask about the
origin of mass you know and like looking
for the higgs mechanism and things they
never like we need to find the
historical origins of life in the early
unit although those things are related
right so um so this problem of origins
of life in the lab i think is really
important but the the higgs is a good
example because you had theory to guide
it so somehow you need to have an
explanatory framework
that
can say that we should be looking for
these features
and explain why they might be there and
then be able to do the experiment and
demonstrate that it matches with the
theory but it has to be something
that is outside sort of the paradigm of
what we might expect based on what we
know right so this is a really sort of
tall order
um and
i think um
i mean i i guess the way people would
think about it is like you know if you
had a bacteria that climbed out of your
test tube or something and it was like
you know moving around on the surface
that would be ultimate validation you
saw the original life in an experiment
but i don't think that's quite what
we're looking for i think what what
we're looking for is evidence of when
information that originated within
the bounds of your experiment and you
can demonstratively prove emerge
spontaneously in your experiment wasn't
put in by you
actually started to govern the future
dynamics of that system and specify it
and you could somehow relate those two
features directly so you know that the
program specifying
what's happening in that system is
actually internal to that system like
say you have a chemical thing in a box
well
so that's that's one nobel prize with
the experiment which is like
information in some fundamental way
originated
within the constraints of the system
without you injecting anything but
another experiment is
you injected something yeah
and got out information yes so like you
injected
i don't know like uh
like some sugar and like something
something that doesn't necessarily feel
like it should be information yeah so i
actually no i mean sugar is information
right so part of the argument here is
that every physical object
is
well it's information but it's a set of
causal histories and also a set of
possible futures so there's an
experiment um that i've talked a lot
about uh with lee cronin but also with
michael lockman and chris kempies who
are at santa fe about this idea that
sometimes we talk about is like seating
assembly um which is you take a high
high complexity like a an object that
exists in the universe because of a long
causal history and you seed it into a
system of lower causal history and then
suddenly you see all of this complexity
being generated so i think another
validation of the physics would be
say you engineer an organism by by
purposefully
introducing something where you
understand the relationship between the
causal history of the organism
and the say very complex chemical set of
ingredients you're adding to it and then
you can predict the future evolution of
that system to some
statistical
uh set of constraints and possibilities
for what it will look like
in the future
you know i'm a physical structure
obviously like i i'm composed of atoms
the configuration of them and the fact
that they happen to be me
is because i'm not actually my atoms i
am a informational pattern that keeps
re-patterning those atoms into sarah um
and i have also associated to me is like
a space of possible things that could
exist
that i can help mediate come into
existence because of the information in
my history
and so
when you understand sort of that
time is a real thing embedded in a
physical object
then it becomes possible to talk about
how
histories when they interact
and history is not a unique thing it's a
set of possibilities when they interact
how do they specify what's coming next
and then where does the novelty come
from in that structure because some of
it is kind of things that haven't
existed in the past can exist in the
future
let me ask about this entity that you
call sarah yes i talk to myself about
myself in third person sometimes i don't
know why
uh
so maybe this is a good time to bring up
consciousness sure
it's been here all along
wow
has it so what i mean at least in this
conversation i think i've been conscious
most of it but maybe i haven't well yeah
speak so speak for yourself you're
you're you're projecting your
consciences onto me you don't know if
i'm conscious or not is it
um you're right is that uh
he talked about the physics of existence
he talked about the emergence of um
of causality uh sorry you talked about
causality and time being fundamental to
the universe
does consciousness fit into all of this
like uh
do you draw any kind of inspiration or
value with the idea of pan psychism
that maybe one of the things that we
ought to understand is the physics of
consciousness
like
one of the missing pieces
in the physics view of the world is
understanding the physics of
consciousness or like that word
has so many concepts underneath it but
let's put it
let's put consciousness as a label on a
black box of mystery that we don't
understand
do you think
that black box holds the key
to uh finally answering the question of
the physics of life
the problems are absolutely related i
think um most and i'm interested in both
because i'm just interested in what we
are and to me the most interesting
feature of what we are is our minds and
the way they interact with other minds
like minds are the most beautiful thing
that exists in the universe so how did
they come to be
i'm sorry to interrupt so when you say
we you mean humans i mean humans right
now but i but that's because i'm a human
i think i am you think there's something
special to this particular no no no um
no um
i don't i'm not a human-centric thinker
but are you one entity you said a bunch
of stuff came together to make a sarah
like
yourself
as one entity are you just
a bunch of different components like is
there any value to understand the
physics of sarah like or are you just a
bunch of different things that are like
a nice little temporary side effect yeah
you could think of me as a bundle of
information that just became temporarily
aggregated or individual yeah that's
fine i agree with that view
um
okay i think that is a compliment
actually but you you've
but nevertheless that bundle of
information has become conscious or at
least keeps calling her self-conscious
yeah i think i'm conscious right now but
i might not be but that's okay um or you
wouldn't know um so yeah so this is the
problem so yeah usually people when
they're talking about consciousness are
worried about the subjective experience
and so i think that's why you're saying
i don't know if you're conscious because
i don't know if you're experiencing this
conversation right now
um and nor do you know if i'm
experienced in the conversation right
now
and so this is why this is called the
hard problem of consciousness because it
seems impenetrable from the outside to
know if something's having a conscious
experience um
and i really like um
the idea of also like the hard problem
of matter which is related to the hard
problem of consciousness which is you
don't know the intrinsic properties of
an electron not interacting say for
example with anything else in the
universe all the properties of anything
that exists in the universe are divine
by its interaction because you have to
interact with it in order to be able to
observe it so we can only actually know
the things that are observable from the
outside and so this is one of the
reasons that consciousness is hard for
science because you're asking questions
about something that's subjective and
supposed to be intrinsic to what that
thing is as it exists and how it feels
about existing
and so
i have thought a lot about this problem
and its relationship to the problem of
life and the only thing i can come up
with to try to make
that problem
scientifically tractable
and also related to how i think about
the physics of life
is to ask the question
are there things that can only