Kind: captions
Language: en
every star in the sky probably has
planets Y and life is probably emerging
on these planets but I think the
commentarial space Associated to these
planets is so different our causal cones
are never going to overlap or not easily
and this is a thing that makes me sad
about alien life why why we have to
create alien life in the lab as quickly
as possible because I don't know if we
are going to be able to be able to
build um
architectures that will intersect with
alien intelligence architectures
intersect you you know mean in time or
space time and the ability to
communicate the ability to communicate
yeah my biggest fear in a way is that
life is everywhere but we become
infinitely more lonely because of our
Scaffolding in that commentarial
space the following is a conversation
with Lee Cronin his third time in this
podcast he is a chemist from University
of Glasgow who is one of the most Most
Fascinating brilliant and fun to talk to
scientists I've ever had the pleasure of
getting to know this is Alex freeden
podcast to support it please check out
our sponsors in the description and now
dear friends here's Lee
Cronin so your big assembly Theory paper
was published in nature congratulations
thanks it created uh I think it's fair
to say a lot of controversy but also a
lot of interesting discussion so maybe I
can try try to summarize assembly Theory
and you tell me if I'm wrong okay for it
so assembly Theory says that if we look
at any object in the universe any object
that we can quantify how complex it is
by trying to find the number of steps it
took to create it and also we can
determine if it was built by a process
akin to evolution by looking at how many
copies of the object there are yep
that's spot on y spot on spot on I was
not expecting that okay so let's go
through
definitions so there's a central
equation I'd love to uh talk about but
definition wise what is an
object um yeah an object so from so if
I'm going to try to be as meticulous as
possible objects need to be
finite um and they need to be
decomposable into
subunits all human-made artifacts
objects um is a Planet an object
probably yes in the if you scale out so
an object is finite and countable and
decomposable um I suppose mathematically
but yeah I still I still wake up some
days and go to think to myself what is
an object because it's it's it's a
non-trivial um question persists over
time I'm quoting from the paper here an
object that's finite is distinguishable
sure that's a weird adjective
distinguishable we've had so many people
help offering to rewrite the paper after
it came out you wouldn't believe it's so
funny persists over time and is
breakable such that the set of
constraints to construct it from
elementary building blocks is
quantifiable such that the set of
constraints to construct it from
elementary building blocks is
quantifiable the history is in the
object it's kind of cool right so okay
so we finds the object is it's history
or memory whichever is the sexier word
I'm happy with both depending on the day
okay so the set of steps it took to
create the object so there's a
sense in which every object in the
universe has a history Y and that is
part of the thing that is used to
describe its complexity how complicated
it is okay what is an assembly index so
the assembly index if you to take the
object apart and be super lazy about it
or minimal say what it because you know
it's like you've got a really short-term
memory so what you do is you lay all the
parts on the path and you find the
minimum um number of steps you take on
the path to add the parts together to to
to reproduce the object and that minimum
number is the assembly index is a
minimum bound and it was always my
intuition the minimum bound an assembly
theory was really important and I only
worked out why a few weeks ago which is
kind of funny because I was just like no
this is Sacra sank I don't know why it
will come to me one day and then when I
was pushed by a bunch of
mathematicians um we we we came up with
the the correct physical explanation
which I can get to but it's the minimum
and it's really important it's the
minimum and the reason I knew the
minimum was right is because we could
measure it so almost before this paper
came out with with published papers
explain how you can measure the assembly
in effect of molecules okay so that's
not so trivial to figure out so when you
look at an object we can say a molecule
we can say object more generally mhm to
figure out the minimum number of steps
it takes to create that
object that doesn't seem like a trivial
thing to do so with molecules is it's
not trivial but it is possible because
what you can do and because I'm I'm a
chemist so I'm kind of like I see the
lens of the world for just chemistry um
um I break the molecule apart break
bonds and if you break up if you take a
molecule and you break it all apart you
have a bunch of atoms and then you say
okay I'm going to then Form B take the
atoms and form bonds and go up the the
chain of events to make the molecule and
that's what made me realize take a toy
example literally toy example take a
Lego object which is broken up of Lego
blocks so you could do exactly the same
thing in this case the Lego blocks are
naturally the smallest they're the at
in the actual composite Lego
architecture but then if you maybe take
you know um a couple of blocks and put
them together in a certain way maybe
they have a they offset in some way that
offset is on the memory you can use that
offset again with only a penalty of one
and you can then make a square triangle
and keep going and you remember those
motifs on the Chain so you can then leap
from the the start with all the Lego
blocks or atoms just laid out in front
of you say right I'll take you you you
connect and do the least amount of work
so it's really like uh the the smallest
um um steps you can take on the graph to
make the object and so for molecules it
came relatively intuitively and then we
started to apply it to language we've
even started to apply it to mathematical
theorems but I'm so well out of my depth
but it looks like you can take minimum
set of axioms and then start to build up
kind of uh mathematical architectures in
the same way and then the shortest path
to get there is something interesting
that I don't yet understand so what's
the computational complexity of figuring
out the shortest path in um with
molecules with language with
mathematical theorems it seems like once
you have the fully constructed Lego
Castle or whatever your favorite Lego
world is figuring out how to get there
from the building basic building blocks
isn't like a is that an empty hard
problem it's a hard problem it's a hard
problem but but actually if you look at
it so the best way to look at it for
let's take a molecule so if the molecule
has um 13 bonds first of all take 13
copies of the molecule and just cut all
the bonds so take cut 12 bonds and then
you just put them in order yeah and then
that's how it works so and you keep
looking for Symmetry and re or or copies
so you can then shorten it as you go
down and that becomes comor quite hard
um for some natural product
molecules um it's comes very hard it's
not impossible but we're looking at the
bounds on that at the moment but as the
object gets bigger it becomes really
hard and but there that's the bad news
but the good news is there are shortcuts
and we might even be able to physically
measure the complexity without
computationally calculating it which is
kind of insane wait wait how would you
do that well in the case of molecule um
so if you shine light on a molecule
let's take it infrared the the molecule
has each of the bonds absorbs the
infrared differently in what we call the
fingerprint region and so it's a bit
like a um and because it's quantized as
well you have all these discrete kind of
absorbances and my intuition after we
realized we could cut molecules up in
Mass Spec that was the first go at this
we did it with using infrared and the
infrared gave us an even better
correlation assembly index and we used
another technique as well in addition to
infrared called NMR nuclear magnetic
resonance which tells you about the
number of different magnetic
environments in a molecule and that also
worked out so we have three techniques
which each of them independently gives
us the same or tending towards the same
assembly index for molecule that we can
calculate mathematically okay so these
are all methods of mass spectrometry
mass spec you scan a molecule it gives
you data in the form of a Mass Spectrum
and you're saying that uh the data
correlates to the assembly index yeah so
how generalizable is that shortcut first
of all to chemistry
and think of all beyond that cuz that
seems like a nice hack and you're
extremely knowledgeable about various
aspects of chemistry so you can say okay
it kind of
correlates but you know the whole idea
behind a su Theory paper and perhaps why
it's so
controversial is that it
reaches
bigger it reaches for the bigger general
theory of objects in the universe yeah
I'd say so I'd agree
so I've started assembly theory of
emoticons with my lab believe it or not
so we take emojis yeah pixelate them
yeah and work out the assembly index for
emoji yeah and then work out how many
emojis you can make on the path of emoji
so there's the Uber emoji from which all
other emo em emojis emerge yeah and then
you can so you can then take a
photograph and by looking at the
shortest path on or by reproducing the
pixels to make the image you want you
can measure that so then you start to be
able to take um spatial data now there's
some problems there what is then the
definition of the object how many pixels
um how do you break it down and so we're
just learning all this right now so how
do you compute the how do you begin to
compute the assembly index of a
graphical like a set of pixels on a 2G
plane that form a thing so you would
first of all determine the resolution so
then how how what is your XY what the
number on the X and Y plane and then
look at the surface area and then you
take all your emojis and make sure
they're all looked at the same
resolution yes and then we will
basically then um do the exactly the
same thing we would do for cutting the
bonds you'd cut bits out of the Emoji on
and look at the the you'd have a bag of
pixels so um and you would then add
those pixels together to make the
overall emoji wait wait a minute but
like first of all not every pixel
I mean this is at the core sort of
machine learning computer vision not
every pixel is that important and
there's like macro features there's
micro features and all that kind of
stuff exactly what like uh you know the
eyes appear in A lot of them the smile
appears in a lot of them so in the same
way in chemistry we assume the bond is
fundamental what we do in there here is
we assume the resolution at the scale
which we do it is fundamental and we're
just working that out and that you're
right that will change right because as
you take your lens out a bit you it will
change dramatically but it but it's just
a new way of looking at not just
compression what we do right now in
computer science and data one big kind
of um uh um kind of misunderstanding is
assembly theory is telling you about how
compressed the object is that's not
right it's a how much information is
required on a chain of events because
the nice thing is if when you do
compression in computer science we're
wandering a bit here but it's kind of
worth wandering I think in you you um
assume you have instantaneous access to
all the information in the memory yeah
in assembly Theory you say no you don't
get access to that memory until you've
done the work and then you've done
access to that memory you can have
access but not to the next one and this
is how in assembly Theory we talk about
the four universes the assembly Universe
the assembly possible and the assembly
contingent and then the assembly
observed and they're all all scales in
this combinatorial universe yeah can you
explain each one of them yep so the
assembly universe is like anything goes
just it's just combinatorial kind of
explosion in everything so that's the
biggest one that's the biggest one it's
massive assembly Universe assembly
possible assembly contingent assembly
observed and uh on the y- axis is
assembly steps in time yeah and you know
in the xais as as the thing expands
Through Time more and more unique
objects appear so yeah so assembly
universe everything goes yeah um
assembly possible laws of physics come
in in this case in chemistry bonds m in
assembly so that means those are
actually constraints I guess yes and
they're the only constraints they're the
constraints at the base so the way to
look at is you got all your atoms
they're quantied you can just bung them
together so then you can become a kind
of so in the way in computer science
speak I suppose the assembly universe is
just like no laws of physics things can
fly through mountains beyond the speed
of light in in the assembly possible you
have to apply the laws of physics but
you can get access to all the motifs
instantaneously with no effort that
means you could make anything then the
assembly contingent says no you can't
have access to the highly assembled
object in the future until you've done
the work in the past on the causal chain
and that's really the really interesting
shift where you go from assembly um
possible to assembly contingent that is
really the key thing in a theory that
says you cannot just have instantaneous
access to all those memories you have to
have done the work somehow the universe
has to have somehow built a um a system
that allows you to select that path um
rather than other paths and then the
final thing the assembly observed is
basically saying oh these are the things
we actually see we can go backwards now
and understand that they have been
created by this this causal process wa
wait a minute so when you say the
universe has to construct the system
that does the work is that like the
environment that'll that that allows for
like selection yeah yeah yeah that's the
thing that does The Selection you could
think about in terms of a Von noyman
Constructor first selection a ribosome
uh Tesla plant assembling Teslas you
know the the difference between the
assembly Universe in Tesla land and the
Tesla Factory is everyone says no Teslas
are just easy they just spring out you
know how to make them all Tesla Factory
you have to put things in sequence and
out comes a Tesla so you're talking
about the factory yes this is this is
really nice super important point is
that when I talk about the universe
having a memory or there's some magic
it's not that it's that tells you that
there must be a process encoded
somewhere in physical reality be it a
cell a Tesla Factory or something else
that is making that object I'm not
saying there's some kind of woo woo
memory in the universe you know morphic
resonance or something I'm saying that
there is an actual causal process that
is being directed constrained in some
way um so it's not kind of uh just
making everything yeah but Le what's the
factory they made the
factory so what what is the so first of
all you assume the laws of physics is uh
just sprung to the existence at the
beginning those are constraints but what
what makes the factory is the
environment that does the selection this
is the question of well it's the first
interesting question that I want to
answer out of four I think the factory
emerges in the envir the interplay
between the environment and the objects
that are being built MH and and here let
me I'll have a go explain to you the the
shortest path so why is the shortest
path important imagine you've got um I'm
going to have to go chemistry for a
moment then abstract it um so imagine
you've got an envir A given environment
that um that you have a budget of atoms
you're just flinging together Y and the
the objective of those atoms that being
flung together in say molecule a um have
to make they have they decompose so
molecules decompose over time so the
molecules um in this environment in this
magic environment have to not die but
they do die there's a there's they have
a halflife so the only way the molecules
can get through that environment out the
other side that's to pretend the
environment is a box and go in out
without dying and there's a there's just
an infinite supply of atoms coming or
well a large
Supply the the molecule gets built but
the molecule that is able to template
itself being built um and survives in
the environment will will basically re
Supreme now let's say that molecule
takes 10
steps now and it and it's using finite
set of atoms right or now let's say
another MO molecule smart ass molecule
we'll call it comes in and can survive
in that
environment and can copy itself but it
only needs five
steps the molecule that only needs five
steps because it's Contin both molecules
are being destroyed but they're creating
themselves faster they can be destroyed
you can see that the shortest path
Reigns Supreme so the shortest path
tells us something super interesting
about the minimal amount of uh
information required to propagate that
Motif into time and space um and it's
just like a kind of it seems to be like
some kind of conservation law so one of
the intuitions you have is the
propagation of motifs in time will be
done by the things that can construct
themselves in the
shortest path yeah so like you can
assume that most the objects in the
universe are built in the shortest in
the most efficient way that the so big
leap I just took there yeah no yeah yes
and no because there are other things so
in the limit yes because you want to
tell the difference between things that
have required a factory to build them
and just random
processes um but you can find instances
where the shortest path isn't taken for
an individual object an individual
function MH um and people go ah that
means the shortest path isn't right and
then I say well I don't know I think
it's right still because so of course
because there are other driving forces
it's not just one molecule now when you
start to now you start to consider two
objects you have a joint assembly space
and it's not now it's a compromise
between not just making a and b in the
shortest path you want to make a and b
in the shortest path which might mean
that a is slightly longer you have
compromise so when you see slightly more
nesting in the construction when you
take a given object that can look longer
but that's because the overall function
is the object is still trying to be
efficient yeah and this is still very
handwavy um and maybe no leg to stand on
but we think we're getting somewhere
with that and there's probably some
parallelization yeah right so this is
all this is not sequential the building
is yeah I guess when you're when you're
talking about complex objects you you
don't have to work sequentially you can
work in parallel you can get your
friends together and they can yeah these
and the the thing we're working on right
now is how to understand these parallel
processes now there's an in a new thing
we've introduced called assembly depth
and assem assembly depth can be lower
than the assembly index for a molecule
when they're cooperating together
because exactly this parallel processing
is going on and my team have been
working this out in the last few weeks
because we're looking at what
compromises does nature need to make
when it's making molecules in the cell
and I I wonder if you know I I maybe
like well I'm always leaping out of um
my competence but in economics I'm just
wondering if you could apply this in
economic process it seems like
capitalism is very good at finding
shortest path you know every time and
there are ludicrous things that happen
because actually the cost functions been
minimized and so I keep seeing parallels
everywhere where there are complex
nested systems where if you give it
enough time and you introduce a bit of
heterogeneity the system readjusts and
finds a new shortest path but the
shortest path isn't fixed on just one
molecule now it's in the actual
existence of the object over time and
that object could be a city it could be
a cell it could be a factory but I think
we're going Way Beyond molecules and and
my competence probably should go back to
molecules but hey all right before we
get too far let's talk about the
assembly
equation okay how should we do this all
let me just even read that part of the
paper we Define assembly as the total
amount of selection necessary to produce
an ensemble of observed objects
Quantified using equation
one the equation basically has a on one
side which is the Assembly of The
Ensemble MH and then a
sum from one to n where n is the total
number of unique
objects and then there is a few
variables in there that include the
assembly
index the copy number which we'll talk
about that's an interesting I don't
remember you talking about that that's
an interesting addition and I think a
powerful one has to do with what that
you can create pretty complex objects
randomly mhm and in order to know that
they're not random that there's a
factory involved you need to see a bunch
of them that's that's the intuition
there it's an interesting intuition and
then uh some
normalization what else is it n n minus
one just to make sure that more than one
object one object could be a oneof and r
yep and then you have more than one
identical object that's interesting when
when there's when there's two of a thing
two of a thing is super important
especially if the IND index assembly
index is high so uh we could say several
questions here one let's talk about
selection what is this term selection
what is this term evolution that we're
referring to which which aspect of
darwinian evolution are we referring to
that's interesting here so yeah so this
is probably what you know the paper we
should talk about the paper for a second
the paper did what it did is it kind of
annoyed um we didn't know I mean it got
intention and obviously angry people the
angry people were annoyed there's angry
people in the world that's good so what
happened is the evolutionary biologist
got angry we were not expecting that
because we thought evolutionary bodies
would be cool I knew that some not many
computational complexity people will get
angry because I'd kind of been poking
them and maybe I deserved it but I was
trying to poke them in a productive way
mhm and then the physicist kind of got
grumpy because the initial conditions
tell everything the Prebiotic chemist
got slightly grumpy because there's not
enough chemistry in there then finally
when the creationist said it wasn't
creationist enough I was like right I've
done my job the phys well you say in the
physics they
say because you're basically saying that
physics is not enough to tell the story
of how biology emerges I think so and
then they said a few physics is the
beginning and the end of the story
yeah so what happened is the reason why
people put the phone down on the call of
the paper if you if you view reading the
paper like a phone call they got to the
abstract Y and in the abstract it's
first sentence is pretty the first two
sentences caused everybody scientists
have grappled with reconciling
biological evolution with the immutable
laws of the universe defined by physics
true right there's nothing wrong with
that statement totally
true yeah these laws underpin life's SW
Evolution and the development of human
culture and Technology yet they do not
predict the emergence of these
phenomena Wow first of all we should say
the title of the paper this is paper was
accepted and published in nature the
title is assembly Theory explains and
quantifies selection and evolution very
humble title and and the the the
entirety of the paper I think uh
presents interesting ideas but reaches
High I am not
I would do it all again this paper was
actually on the pre-print server for
over a year you regret nothing yeah I I
I think yeah I don't regret anything you
and Frank Sinatra did it your way what I
love about being a scientist is kind of
sometimes I'm because I'm a bit dim I'm
like and I don't understand what people
telling me I want to get to the point
this paper says Hey laws of physics are
really cool the universe is
great but they don't really it's not
intuitive that you just run the standard
model and get life out I think most
physicists might go yeah there's this
you know it's not just we can't just go
back and say that's what happened
because physics can't explain the origin
of life yet do doesn't mean it won't or
can't okay just to be clear sorry
intelligent designers we are going to
get there second point we say that
Evolution works but we don't know how
Evolution got going so biological
evolution and biological selection so
for me this seems like a simple
continuum so when I mentioned selection
and evolution in the title I think and
in the abstract we should have maybe
prefaced that and said non-biological
selection and non-biological evolutions
and then that might have made it even
more crystal clear but I didn't think
that biology evolutionary biology should
be so bold to claim own ownership of
selection and evolution and secondly a
lot of evolutionary biologists seem to
dismiss the origin of Life questions to
say it's obvious and and that causes a
real problem scientifically because when
two different when the physicists are
like we own the universe universe is
good we explain all of it look at us and
the biologist say we can explain biology
and the poor chemistry in the in in the
middle ground but hang
on and this paper kind of says hey there
is an
interesting
um disconnect between physics and
biology and that's at the point which
memories get made in chemistry through
bonds and hey let's look at this close
and see if we can quantify it so yeah I
mean I never expected the paper to to to
kind of get that much interest and still
I mean it's only been published just
over a month ago now so just to Ling on
the selection what is
the broader sense of what selection
means yeah that's really good for
selection selection so I think for
selection you need so this is where for
me the concept of an object is something
that can persist in time and and not die
but basically can be broken up mhm so so
if I was going to kind of bolster the
definition of an object so so if if
something can
form and persist for a a a long period
of time um
under an existing environment that could
destroy other and I'm going to use
anthropomorphic terms I apologize that
weaker objects um or less
robust um then the environment could
have selected that so good chemistry
examples if you took some carbon and you
made a chain of carbon atoms whereas if
you took some I don't know some carbon
nitrogen and oxygen and made chains from
those you'd start to get different
reactions and rearrangements so a carb a
chain of carbon atoms might be more
resistant to falling apart uh under
acidic or basic conditions um versus
another set of molecules so surviv in
that environment so the acid Pond the
molecule the the molecu the resistant
molecule can get through and and then
then that molecule goes into another
environment so that environment now
maybe being an acid Bond it's a basic
Pond or maybe it's an oxidizing Pond and
so if you've got carbon and it goes an
oxidizing pond maybe the carbon starts
to oxidize and break apart so you go
through all these kind of obstacle
courses if you like given by reality so
selection is the ability happens when an
object survives in an environment for
some time but and this is a thing that's
super subtle the object has to be
continually being destroyed and made by
process so it's not just about the proc
the object now it's about the process
and time that makes it because a rock
could just stand on the mountain side
for four billion years and nothing
happened to it and that's not
necessarily really Advanced selection so
for selection to get really interesting
you need to have a turnover in time you
need to be continually creating objects
producing them what we call Discovery
Time so there's a discovery time for an
object when that object is discovered if
it's say a molecule that can then act on
itself or the chain of events that
caused itself to bolster its formation
then you go from Discovery time to
production time and suddenly you have
more of it in the universe so it could
be a self-replicating molecule and the
interaction of the molecule in the
environment in the warm little part or
in the sea or wherever in the bubble
could then start to build a Proto
Factory the environment so really to
answer your question what the factory is
the factory is the environment but it's
not very autonomous it's not very
redundant there's lots of things that
could go wrong so once you get high
enough up the the the hierarchy of
networks of
interactions something needs to happen
that needs to be compressed into a
smaller volume and made resistant robust
because in biology
selection and evolution is robust that
you have error correction built in you
have really you know there's good ways
of basically making sure propagation
goes on so really the difference between
inorganic abiotic selection and
evolution and evolution and stuff in
biology is
robustness um the ability to to kind of
propagate over over in the the ability
survive in lots of different
environments whereas our poor little an
organic salt molecule whatever just dies
in lots of different environments so
there's something super special that
happens from the inorganic envir
molecule in the environment that kills
it to where you've got Evolution and
cells can survive
everywhere how special is that how do
you know those kinds of uh Evolution
factories aren't everywhere in the
universe I I don't and I'm excited cuz I
think selection isn't special at all I
think what is special is the history of
the environments on Earth that gave rise
to the first cell that now has you know
has taken all those
environments and is now more autonomous
and I would like to think that you know
this
paper could be very
wrong but I don't think it's very wrong
it mean certainly wrong but it's less
wrong than some other ideas I hope right
and if this allow Ires us to go and look
for selection in the universe because we
now have an equation where we can say we
can look for selection going on and say
oh that's interesting we seem to have a
pro process that's giving that's giving
us High copy number objects that also
are highly complex but that doesn't look
like Life as We Know It And we use that
and say oh there's a hydrothermal vent
oh there's a process going on there's
molecular networks because the assembly
equation is not only meant to identify
at the higher end advanced
selection what you get I would call in
biology super Advanced selection and
even I you could use the assembly
equation to look for technology and um
God forbid we could talk about
Consciousness and abstraction but let's
keep it primitive molecules and biology
so I think the real power of the
assembly equation is to is to say how
much selection is going on in this space
and there there's a really simple
thought experiment I could do is you you
know have a little petri dish and on
that petri dish you put some simple food
so the assembly index of all the sugars
and everything is quite low so then and
you put a single e cell of e eoli cell
yeah and then you say I'm going to I'm
going to measure the assembly in the
amount of assembly in the box so it's
quite low but the rate of change of
assembly da DT will go vom sigmoidal as
it eats all the food and the number of
coli cells will re will replicate
because they take all the food they copy
themselves the assembly index of all the
molecules goes up up up and up up until
the food is exhausted in the box so now
the now the eoli stop I mean d is
probably a strong way they stop
respiring because all the food is gone
but suddenly the amount of assembly in
the box has gone up gigantically because
of that one eoli Factory has just eaten
through M lots of other eoli Factory has
run out of food and stopped and so that
looking at that so in the initial box
although the amount of assembly was
really small it was able to make
replicate and use all the food and go up
and that's what we're trying to do in
the lab actually is kind of make those
kind of experiments and see if we can
spot the emergence of molecular networks
that are producing complexity as we feed
in raw materials and we feed a challenge
an environment you know we try and kill
the molecules and and and really that's
the main kind of idea for the entire
paper yeah and see if you can measure
the changes in the assembly index
throughout the whole system yeah okay
what what about if if I show up to new
planet we go to Mars or some other
planet from a different solar system and
how do we use assembly index there to
discover alien life um in very simply
actually if we let's say we'll go to
Mars with a mass spectrometer with a
sufficiently high resolution so what you
have to be able to do so good thing
about Mass speec um is that you can um
select a molecule from the mass and then
if it's high enough resolution you can
be more and more sure that you're just
seeing um identical copies you can count
them and then you fragment them and you
count the number of fragments and look
at the molecular weight and the higher
the molecular weight and the higher the
number of the fragments the higher the
assembly index so if you go to Ms and
you take a mass spec or high enough
resolution and you can find molecules
I'll give gu guide on Earth if you could
find molecules say greater than 350
molecular weight with more than 15
fragments you have found artifacts that
can only be produced at least on Earth
by life now you would say oh well maybe
the geological process I would argue
very vly that that is not the case but
we can say look if you don't like the
cut off on
Earth go up higher 30 100 right because
there's going to be a point where you
can find a molecule with so many
different parts the chances of you
getting a molecule that has a 100
different parts um and finding a million
identical copies you know that's that's
just impossible that could never happen
in an infinite set of universes can you
just Linger on this copy number
thing uh a million different
copies what do you mean by copies and
why is the number of copies
important yeah that was so interesting
and the um
I always understood the copy number was
really important but I never explained
it properly
for ages um and it be I kept having this
it goes back to this if I give you a um
I don't know a really complicated
molecule and I say it's complicated you
could say hey that's really complicated
but is it just really random and so so I
realized that ultimate Randomness and
ultimate complexity are
indistinguishable
until you can um you can see a structure
in the randomness so you can see copies
so copies imply
structure
yeah the fact I mean there's a deep
profound thing in there cuz like if you
just have a
random random process you're going to
get a lot of complex beautiful
sophisticated things mhm what makes
them complex in the way we think life is
complex or um yeah something like a a
factory that's operating under selection
processes there should be copies is
there like some looseness about copies
like what does it mean for two objects
to be equal it it's it's all to do with
the the telescope or the microscope
you're using and so at the the maximum
resolution so in the nice thing about
the nice thing about chemists is they
have this concept of the molecule and
they're all familiar with a molecule and
molecules you can hold you know on your
hand lots of them identical copies a
molecues actually a super important
thing chemistry to say look you can have
a mole of a molecule and avagadro's
number of molecules and they're
identical what does that mean that means
that the molecular composition the
bonding and so on the configuration is
all is is indistinguishable you can hold
them together you can overlay them so
the way of do it is if I say here's a
bag um of 10 identical molecules let's
prove they're identical you pick one out
of the the out of the bag and you
basically observe it using some
technique and then you put it you take
it away and then you take another one
out If You observe it using technique
you see no differences they're identical
it's really interesting to get right
because if you take say two molecules
molecules can be in different
vibrational rotational States they're
moving all the time so for this respect
identical molecules have identical
bonding in this case we don't even um
talk about chirality because we don't
have a chirality detector so two
identical molecules in one conception
sembly Theory basically um considers
both hands as being the same um but of
but of course they're not they're
different as soon as you have a chyro
distinguisher detect to detect the left
and the right hand they become different
and so it's to do with the detection
system that you have and the resolution
so I wonder if there's an art and
science to the which detection system is
used when you show up to a new planet
yeah yeah yeah so like you're talking
about chemistry a lot today we have kind
of standardized detection systems right
of how to compare
molecules so you know when you start to
talk about emojis and language and uh
mathematical theorems
and uh I don't know more sophisticated
things at different scale at a smaller
scale than molecules at a larger scale
the
molecules like what
detection like if if we look at the
difference between you and me Lex andly
are we the same are we different sure I
mean of course we're different close up
but if you zoom out a little bit will
morphologically look the
same you know height and characteristics
hair length stuff like that also like
the species and yeah yeah yeah and and
also there's a sense why we're both from
Earth yeah I I agree I mean this is the
power of assembly theory in that regard
that you if if you so if everything so
the way to look at it if you have a box
of objects if they're all if they're all
indistinguishable um then using your
Technique you then you what you then do
is you then look at the assembly index
now if the assembly index of them is
really low right and they all they're
all indistinguishable then You' then
it's telling you that you have to go to
another resolution so that would be you
know it's kind of a sighting scale it's
kind of nice so got it so those two kind
of are attentional with each other the
co the number of copies and the assembly
index
yeah that's really really interesting so
okay so you show up to a new planet you
doing what I would do Mass Spec I would
bring on a sample of what like First of
all like how big of a scoop do you take
do you just take a scoop like what like
uh so we're looking for primitive life I
would I would look yeah so if you're
just going to Mars or Titan or Enceladus
or somewhere so a number of ways of
doing it so you could take a large scoop
or you go for the atmosphere and detect
stuff so and you can make a li um a life
meter right so um one of uh uh Sarah's
colleagues at ASU Paul Davis keeps
calling it a life me a life meter which
is quite a nice idea because you think
about it if you've got um a living
system that's producing these uh highly
complex molecules and they drift away
and they're in a highly um kind of
um demanding environment they could be
burnt right so they could just be
falling apart so you want to sniff a
little bit of complexity and say warmer
warmer warmer oh we' found life found
the alien we found we found the alien
Elon Musk smoking a joint in the bottom
of the cave on mars or Elon himself
whatever right you say okay found it so
what you can do is the mass spectrometer
um you could just look for things in the
gas phase or you go on the surface drill
down because you want to find molecules
that are well you you've either got to
find the source living system because
the problem with just looking for
complexity is it gets burnt away so in a
harsh environment on on on say on the M
surface of Mars there's a very low
probability that you're going to find
really complex molecules because of all
the radiation and so on if you drill
down a little bit you could drill down a
bit into into a soil that's billions of
years old then I would put in some
solvent water alcohol or something or
take a a scoop put it in put VI make it
volatile put it into the mass
spectrometer and just try and detect
High complexity High abundant molecules
and if you get them hey Presto you can
have evidence of Life mhm wouldn't that
then be great if you could say okay
we've found evidence of life now we want
to keep keep the life meter keep
searching for more and more complexity
until you actually find living cells and
you get those new living cells and then
and then you could bring them back to
Earth or you could try and sequence them
you could see that they have different
DNA and proteins go along the gradient
of the life meter how would you build a
life meter let's say we're together
starting new company launching a life
meter spectrometer would be the first
way of doing it just take no no no but
that's that's um that's one of the major
components of it but I'm talking about
like what if it's a device we got to and
branding logo we got to talk that that's
later but what's the input what's the
like how do you get to the um a metered
output so I would I would take a life so
my my life meter our life meter there
you go thank you yeah you're
welcome um uh would have both infrared
and mpect so it would have two ports so
it could shine a light um and so what it
would do is you would have a a vacuum
chamber and you would have an
electrostatic analyzer and you'd have a
monochromator to producing infrared um
you'd add the sum so You' take a scoop
of the sample put it in the Life meter
it would then add a solvent or heat up
the sample so some volatiles come off
the volatiles would then be put into the
into the mass spectromet into
electrostatic trap and you'd weigh them
all molecules and fragment them M
alternatively you'd shine infrared light
on them you count the number of bands
but you'd have to in that case do some
separation because you want to separate
in and so in Mass Spec it's really nice
and convenient because you can separate
electrostatically but um you need to
have that can you do it in real time
yeah pretty much pretty much yeah so
let's go all the way back so this okay
we're really going get this the the
lexa's life meat Lex and
Lees it's a good it's a good good uh
good ring to it all right so um you have
a
you have a vacuum chamber you have a
little nose the nose would have um
some a a packing material so you would
take your your sample add it onto the
nose add a solvent or a gas it would
then be sucked up the nose and that
would be separated using Chrome what we
call chromatography and then as each
band comes off the nose we would then do
mass backc and infrared and in the count
in the case of infrared count the number
of bands in the case of mass count the
number of fragments and weigh it and the
further up in molecular weight range for
the mass spec and the number of bands
you go up and up and up from the you
know dead interesting interesting over
the threshold oh my gosh Earth life and
then right up to bat crazy this is
definitely um you know alien
intelligence that's made this life right
you could almost go all the way there
same in the infrared and it's pretty
simple the thing that is really
problematical is that for many years
decades what people have done and and I
can't blame them is they've rather
they've been obsessing about small
biomarkers on that we find on Earth
amino acids like single amino acids or
evidence of small molecules and these
things and looking for those run looking
for complexity the well the be beautiful
thing about this is you can look for um
complexity without Earth chemistry bias
or Earth biology bias so assembly theory
is just a way of saying hey complexity
and abundance is evidence of selection
that's how universal life meter will
work complexity in abundance is evidence
of
selection okay so let's apply our life
meter to
Earth
so what you know if we were just to
apply assembly index measurements to
Earth what do what what kind of stuff
are going to be get uh are going to get
what's
impressive about some of the complexity
on Earth so we did this a few years ago
in that um when I was trying to convince
NASA and colleagues that this technique
could work and honestly it's so funny
because everyone's like no ain't going
to
work and I was just like because the
chemist was saying of course there are
complicated molecules out there you can
detect that just form randomly I was
like re really that's like that was like
you know as a bit like
a um I don't know someone saying of
course Darwin textbook was just written
randomly by some monkeys a typew just
for me it was like really and and and I
pushed a lot on the chemist now and I
think most of them are on board but not
totally I re really had some big
arguments but the copy number caught
there cuz I think I confused the chemist
by saying one off and then when I made
clear about the copy number I think that
made it a little bit easier just to
clarify chemist might say that of course
out there outside of Earth there's
complex molecules yes okay and then
you're saying wait a minute that's like
saying of course there's aliens out
there like you yeah exactly that okay
exactly but you're you're saying you
clarify
that that's actually a very interesting
question and we should be looking for
complex molecules of which the copy
number is two or greater yeah exactly so
on Earth so coming back to Earth what we
did is we took a whole bunch of samples
we and we were running Prebiotic
chemistry experiments in the lab um we
took various inorganic minerals and
extracted them look at the volatile
because there's a special way of
treating minerals and polymers and
assembly Theory where what in this in
our life machine we're looking at
molecules we don't care about polymers
because they don't they're not volatile
you can't hold them they're not how how
can you make if you can't assern that
they're identical then it's very
difficult for you to to to work out if
there undergone selection or they're
just a random mess same with some
minerals but we can come back to that so
basically what you do we got whole loads
of samples inorganic ones we got a load
of we got Scotch whiskey and also got
took arbag which is one of my favorite
whiskies which is very pey and another
whis what do py mean is like um so the
way that on on um in Scotland in Isa
which is Little Island the the the the
the scotch the SC the whiskey is led to
mature and barrels and um the
the it said that the peak you know the
the the complex molecules in the Pete
might find their way through into the
whiskey and that's what gives it this
intense brown color and really complex
flavor it's literally molecular
complexity that does that and so you
know vulka is the complete opposite it's
just pure right the better the whiskey
the higher the assembly index the the
higher the assembly index the better the
whiskey that's I mean I really love deep
PT Scottish whiskies near my house there
is a a low one of the the lowland
distilleries called gleny it's still
beautiful whiskey but not as complex so
for fun I C took some Glen coin whiskey
andard B and put them into the mass
backck and measure the assembly index I
also got eoli so the way we do it take
the eoli break the cell apart take it
all apart um and also got some beer and
and people were ridiculing us saying oh
beer is evidence of complexity one of
the one of the computational uh
complexity people was just
throwing yeah we kind of kind of his
very vigorous in his disagreement of
assembly theory was just saying you know
you don't know what you're doing even
beer is more complicated than human what
we didn't realize is that it's not beer
per se is taking the yeast extract
taking the extract breaking the cells
extracting the molecules and just
looking at the profile of the molecues
see if there's anything over the freshh
hold and we also put in a really complex
molecule taxo so we took all of these
but also gave us I think five samples
and they wouldn't tell us what they are
they said no we don't believe you're can
get this to work and they really you
know they gave us some super complex
samples and they gave us two fossils one
that was a million years old and one was
a 10,000 years old um SE something from
Antarctica seabed they gave us IM meras
and mea right and a few others put them
through the system so I we we took all
the samples treated them all identically
put them into Mass Spec fragmented them
counted in this case implicit in the
measurement was we um you in Mass backc
you only
detect um Peaks when you've got more
than say let's say 10,000 identical
molecules so the copy numberers already
baked in but wasn't Quantified which is
super important there this was in the
first paper cuz I was like it's abundant
of
course um and when you then took it all
out we found that the biological
samples um gave you um molecules that
had an assembly index greater than 15
and all the abiotic samples were less
than 15 and then we took the NASA
samples and we looked at the ones that
were more than 15 or less than 15 and we
gave them back to NASA and they're like
oh gosh yep dead Living Dead living you
got it and um and that's what we found
on Earth um that's a success yeah oh
yeah resounding success um well can can
you uh just go back to the beer and the
eoli so what's the assembly index on
those so what you were able to do is
like the assembly index um of we fou