Kind: captions
Language: en
the following is a conversation with
frank wilceck a theoretical physicist at
mit
who won the nobel prize for the
co-discovery of
asymptotic freedom in the theory of
strong interaction
quick mention of our sponsors the
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description to support this podcast
as a side note let me say a word about
asymptotic freedom
protons and neutrons make up the nucleus
of an atom strong interaction
is responsible for the strong nuclear
force that binds them
but strong interaction also holds
together the quarks
that make up the protons and neutrons
frank wilcek
david gross and david pulitzer came up
with a theory postulating
that when quarks come really close to
one another the attraction abates
and they behave like free particles this
is called
asymptotic freedom this happens at
very very high energies which is also
where all the fun is this is the lex
friedman podcast
and here is my conversation with frank
wilcheck
what is the most beautiful idea in
physics
the most beautiful idea in physics is
that we can get a compact description of
the world that's
very precise and very full
at the level of the operating system of
the world
um that's an extraordinary gift
and we get we get worried when we
uh have find discrepancies between our
uh description of the world and and
what's actually observed
at the level even of a part in a billion
you actually have this quote
from einstein that the the most
incomprehensible thing
about the universe is it's co is that it
is comprehensible something like that
yes that's so that's the most beautiful
surprise that i think uh
that that really was the to me the
most profound result of the scientific
revolution of this
of the 17th century with uh
the shining example of newtonian physics
that you could
aspire to completeness precision
and a concise description of the world
of the operating system
and it's gotten better and better over
the years
and that's the continuing miracle now
there are a lot of beautiful
sub-miracles too
the form of the equations is governed by
high degrees of symmetry and
and they have a very surprising kind of
mind-expanding structure especially in
quantum mechanics
but if we have to say that the single
most
beautiful revelation is that
in fact uh the world is comprehensible
would you say that's a fact or hope it's
a fact
we can do we you can point to things
like
uh the rise of
uh gross
pro gross national products grow you
know per capita
around the world as a result of the
scientific revolution you can see it all
around you
uh uh uh in in recent developments with
exponents
so exponential production of wealth
control of nature
at uh a very profound level
where we do things like sense tiny tiny
tiny tiny vibrations
to tell that there are black holes
colliding far away
or we uh test laws as i
alluded to whether to part in a billion
and do
you know things and what appear on the
surface to be entirely different
conceptual universes i mean on the one
hand
pencil and paper or nowadays computers
that that
calculate abstractions and on the other
hand magnets and accelerators and
detectors that look at the
behavior of fundamental particles and
and these
different universes have to agree or
else we get very upset
and that's uh it's an amazing thing if
you think about it so
and it's telling us that we do
understand a lot about nature at a very
profound
level and uh
there are still things we don't
understand of course but
as we get better and better answers and
better and better
ability to address difficult questions
we can ask
more and more ambitious questions well i
guess the hope
part of that is because we are
surrounded by mystery
so we've one way to say it if you look
at the growth the
gdp over time that we figured out quite
a lot and we're
able to improve the quality of life
because of that
and we've figured out some fundamental
things about this universe but we still
don't know how much mystery there is
and it's also possible that there's some
things that are in fact
incomprehensible to both our minds
and the tools of science like we the
the sad thing is we may not know it
because
in fact they are incomprehensible and
that's the open question is
how much of the universe is
comprehensible if we figured out
the the everything uh what's inside the
black hole
and everything that happened at the
moment of the big bang
does that still give us the key to
understanding the human mind
and the the emergence of all the
beautiful complexity we see around us
that's not uh like when i when i see
these objects
like i don't know if you've seen them
like cellular automata
uh all these kinds of objects where the
from simple rules emerges complexity yes
it makes you wonder maybe it's not
reducible to simple beautiful
equations the whole thing only parts of
it
that's the tension i was getting at with
the hope well
when we say the universe is
comprehensible we have to
kind of draw careful distinctions about
or uh
definitions about what what we mean by
by that
uh both the university and the con and
the comprehensive
exactly right so uh the
so in certain areas
of understanding reality
we've made extraordinary progress i
would say
in understanding fundamental physical
processes
and getting very precise equations that
really work and
allow us to do uh the profound sculpting
of matter
you know to make computers and iphones
and everything else and they really work
and they're extraordinary productions
uh on the other but uh
and that's all based on the laws of
quantum mechanics and you know they
really
and they really work and then uh
and they give us tremendous control of
nature
on the other hand uh as i said as with
as we get better answers we can also ask
more ambitious questions and there are
certainly things that
have been observed even in the
in what would be usually called the
realm of physics that aren't understood
for instance there seems to be another
source of mass in the universe the
so-called dark matter
that we don't know what it is and it's a
very interesting question what it is
then uh but also as you were alluding to
there
there's it's one thing to know the basic
equations
it's another thing to be able to solve
them
in in important cases so we run a
we run up against the limits of that in
things like
chemistry where we'd like to be able to
design molecules and predict their
behavior
from the equations we think the
equations could do that
in principle but but uh
in practice it's very challenging to
solve them in
in all but very simple cases uh
and then there's the other thing which
is that a lot of what we're interested
in
is uh historically conditioned it's not
uh it's not a matter of the fundamental
equations but about
what has evolved or come out
of of the early universe and formed into
people and frogs and societies and
things
and the laws of physic the basic laws of
physics only take you so far
in the in that it kind of provides a
foundation but doesn't
really you need entirely different
concepts to deal with
uh those kind of uh and
all we one thing i can say about that is
that the laws themselves
point out their limitations that they
kind of their laws for dynamical
evolution so they tell you what happens
if you have a certain starting point but
they don't tell you what the starting
point
should be at least yeah and
uh the other the other thing that
emerges from the equations themselves
is the phenomena of chaos
and sensitivity to initial conditions
which tells us that you have that
there are intrinsic limitations on how
well we can spell out the
consequences of the laws if we try to
apply them see all the apple pie
if you want to what does it make an
apple pie from scratch
you have to build the universe or
something like that well
you're much better off starting with
apples than starting with quarks
let's put it that way in your uh book a
beautiful question you ask
does the world embody beautiful ideas so
the book is centered around this
very interesting question it's like
shakespeare you can like dig in and read
into all the different interpretations
of this question
but at the high level what to use the
connection between
beauty of the world and physics of the
world
in a sense we now have a lot of insight
into what the
the laws are the for the form they take
that and
allow us to understand matter in great
depth and control it
as we as we've discussed uh
it's an extraordinary thing how
mathematically ideal
those equations turn out to be in the
early days of greek philosophy
uh plato had this model of
atoms built out of the five perfectly
symmetrical platonic solids so there was
somehow the idea that mathematical
symmetry
uh should govern the world and uh we've
outplated plato by far
in modern physics because we have
symmetries that are much more extensive
much more powerful
that turn out to be uh the ingredients
out of which we construct our theory of
the world
and and it works and uh
so that's certainly beautiful so
the the math the idea of symmetry which
is
uh a driving inspiration
in much of human art uh especially a
decorative art or like the alhambra or
in
wallpaper designs or things you see
around you everywhere
uh also turns out to be the dominant
theme in
modern fundamental physics symmetry and
its manifestations
the laws turn out to be very to have
these tremendous amounts of symmetry you
can change
the symbols and move them around in
different ways and they still have
the same consequences uh
that so that's that's
uh beautiful and uh
that that uh these things uh these
different
these concepts that humans find
appealing
also turn out to be the concepts that
govern how the world actually works
and i don't think that's an accident i
think the humans
were evolved to be able to interact with
the world in
in ways that are advantageous and to
learn from it
and so we are naturally evolved or
designed to enjoy beauty and
and it's a symmetry and this and the
world has it and that's no
that's why we that's why we resonate
with it well it's interesting that the
ideas of symmetry emerge at
all at many levels of
the hierarchy of the universe so
you're talking about particles but it
also is
at the level of chemistry and biology
and
um and the fact that our
cognitive sort of our perception system
and whatever our cognition is also finds
it appealing or somehow our sense of
what is beautiful is grounded in this
idea of symmetry or the breaking of
symmetry
symmetry is at the core of our
conception of beauty whether it's the
breaking or the non-breaking of the
symmetry
it makes you wonder why
why like uh so i come from russia
in the in the question of dostoyevsky
he's
he has said that beauty will save the
world maybe
maybe as a physicist you can tell me
what do you think he meant by that
i don't i don't know if it saves the
world but it does turn out to be a
tremendous source of insight into the
world
when we uh investigate kind of the
the most fundamental interactions things
that are
hard to access because they occur at
very short distances between
very uh
special kinds of particles whose
properties are only revealed at high
energies
we don't have much to go on from
everyday life but so we have when we
guess what the
so we and then the experiments are
difficult to do so you can't
you can't really uh follow a very
uh holy empirical procedure to
sort of step in the baconian style
figure out the laws kind of step by step
just by accumulating a lot of data
what we actually do is guess and the
guesses
are kind of aesthetic really what what
would be a nice description
that's consistent with what we know and
then you try it out and see if it works
and then
and by gosh it does in in some
in many profound cases uh so
there's that but there's another source
of symmetry which i didn't
talk so much about in uh
in a beautiful question but does
uh relate to your comments and i think
very much relates to
uh the source of symmetry that we find
in biology
and uh in
in our in our heads you know in our
brain
which is that uh although i'd
well it is discussed a bit in in a
beautiful question and and
also in fundamentals is that
when you have
symmetry is also a very important means
of construction
so when you have for instance simple
viruses
that that need to construct their coat
their protein coat the coats often take
the form of platonic solids
and the reason is that the viruses are
really dumb
and they only know how to do one thing
so they make a pentagon then they make
another pentagon and they make another
pentagon and they
all glue together in the same way and
that makes a very symmetrical
object sort of so the rules of
development when you have simple rules
and they
go they work again and again you get
symmetrical patterns that's it's kind of
in in fact it's a recipe also for
generating
fractals you know really like uh
the kind of broccoli that has all this
internal structure and i
wish i had a picture to ship that many
people remember it from the
from the uh uh from the supermarket
and then and you say how did a vegetable
get so intelligent to make such a
beautiful object of all this
fractal structure and the the the secret
is stupidity you just do the same thing
over and over again
and uh in our brains also you know we've
we came out we start from single cells
and they reproduce and they they're each
one
does basically roughly the same thing
they
they uh the the program evolves in time
of course
different different modules get turned
on and off genetic
different regions of the genetic code
get turned on and off
but uh but basically a lot of the same
things are going on and they're simple
things and so you produce the same
patterns over and over again and that's
a recipe for producing symmetry because
you're getting the same thing
in many many places and if you look at
for instance the beautiful drawings of
rahman ikahal the great neuroanatomist
who drew the structure of different
organs
like the hippocampus you see it's very
regular
and very intricate and
it's symmetry in in this in
in that sense it's because it's it's
it's many repeated units that that
uh you can take from one place to the
other and see that they look more or
less the same
but what you're describing this kind of
beauty that we're talking about now
is a very small sample
in terms of space-time in a very big
world
in a very short brief
moment in this long history in your book
fundamentals
10 keys to reality i'd really recommend
people read it
you uh you say that space and time are
pretty big
or very big how big are we talking about
like what uh
can you draw can you tell a brief
history
of space and time it's easy to
tell a brief history but the details get
very
involved of course but uh one thing i'd
like to say is that
if if if you take a broad enough view
the history of the universe is simpler
than the history of sweden say
because you don't you your standards are
lower for for
but just to make it a a a
quantitative i'll just give a few
highlights and it's it's
it's a little bit easier to talk about
time
uh so let's start with that the big bang
occurred
we think the universe was much hotter
and denser and more uniform
about 13.8 billion years ago and that's
what we call the big
bang and it's been expanding and cooling
the matter in it has been expanding and
cooling
ever since so in a real sense the
universe is 13.8 billion years old
that's a big number kind of hard to
think about
a a nice way to think about it though is
to map
it on to one year so if
so let's say the universe just linearly
map the time intervals from
13.8 billion years on to one year so
the the big bang then is that on january
1st at
12 a.m and
uh you wait for quite a long time
before the dinosaur has emerged the
dinosaurs emerge on christmas
it turns out almost 12 months later
getting close to the end yes
and the extinction event that uh
let mammals and ultimately humans
inherit the earth from from the
dinosaurs occurred on december 30th
and all of human history is a small part
of the last day
and so so yes so we
we're occupying only a human lifetime is
a
very very infinitesimal part of this uh
interval of these gigantic cosmic
reaches of time uh and
in space we can tell a very similar
story in fact
a very uh it's convenient to think
that the size of the universe is
the distance that light can travel in
13.8 billion years that's
so it's 13.8 billion light years
that's that's how far you can see out
that's how far
things can signals can reach us from
and um that
is a big distance
because compared to that uh the the
universe
that the earth is a fraction of a light
second
so again we it's really really big
and so we have if we want to think about
the universe as a whole in space and
time
we really need a different kind of
imagination
it's not it's not something you can
grasp in terms of psychological time in
a useful way you have to think
you know you have to use exponential
notation and abstract concepts
to really get any uh hold on on
on these vast times and spaces
on the other hand let me hasten to add
that that doesn't make us small
or make the time that
we have to us small because uh
again looking at those pictures of
you know what our minds are in some
sense of components of our minds these
beautiful drawings of the cellular
patterns inside the brain
you see that there are many many many
processing units
and if you analyze how fast they operate
i try to estimate how many thoughts a
person can have in a lifetime that's
kind of a fuzzy question but i'm very
proud that i
i was able to define it pretty precisely
and it turns out we can we have time for
billions
of meaningful thoughts you know in a
lifetime
so so it's a lot we shouldn't we
shouldn't think of ourselves as terribly
small
either in space or in time because
although we're
small in those dimensions compared to
the universe where
we're large compared to
meaningful units of processing
information
and and being able to conceptualize and
understand things
yeah but 99 of those thoughts are
probably
food sex or internet related but yeah
yeah well they're not that's right only
like point one is nobel prize winning
ideas
but that's true but uh you know there's
more to life than winning nobel prizes
how did you um do that calculate can you
maybe break that apart a little bit just
kind of
for fun sort of an intuition of how we
calculate the number of thoughts the
number of thoughts right there they're
it's necessarily imprecise because a lot
of things are going on in different ways
and what is a thought
but there are several things that point
to more or less the same
[Music]
uh rate of being able to have meaningful
thoughts
uh for instance i'm the one that i think
is
maybe the most penetrating is uh
how fast we can we can process visual
images how to how do we do that
if you've ever watched old movies
you can see that that when well any
movie
in fact that in a motion picture is
really not a motion picture it's
a series of snapshots that are playing
one after the other
and it's the because our brains
also work that way we take snapshots of
the world
integrate over a certain time and then
go on to the next one and then
by post-processing create the illusion
of continuity and flow
we can deal with that and uh
the if the flicker rate is too slow
then you start to see that it's not it's
a series of snapshots
and you can ask what is the what is the
crossover when does it change from being
something that
that is matched to our processing speed
versus
too fast and and it turns out about 40
per second
and then if you take 40 per second as
as how well we how fast we can process
visual images you get
to several billions of thoughts uh
if you similarly if you ask what
what are some of the fastest things that
people can do well you can they can play
video games they can play the piano very
fast if
if they're skilled at it and again you
get to similar
uh units or how fast can people talk you
get to sim
you know within a couple of orders of
magnitude you get more or less to the
same
idea so uh so that's how
you can say that that there's there's
billions of
meaning there's room for billions of
meaningful thoughts
yeah i won't argue for exactly 2 billion
versus 1.8 billion it's not that kind of
question but
but i think any estimate that's
reasonable will come out
within say a hundred billion and a
hundred million
so it's a lot
[Laughter]
it would be interesting to map out for
an individual human being
the landscape of thoughts that they've
sort of traveled if you think of
thoughts as a set of trajectories uh
what what that landscape looks like i
mean
i've been recently really thinking about
uh
this richard dawkins idea of memes
and just all these ideas and the
evolution of ideas inside of one
particular human mind
and how there's there then changed and
evolved by
interaction with other human beings it's
interesting to think about
so if you think the numbers billions
you you think there's also social
interaction so these aren't
uh like there's interaction in the same
way you have
interaction with particles there's
interaction between human thoughts
uh that are perhaps that's that
interaction in itself is fundamental to
the process
of thinking like without social
interaction we would be
like stuck like walking in a circle we
need
we need the perturbation of other humans
to create
change in evolution once you bring in
concepts of uh
interactions and correlations and
relations
then you have what's called a
combinatorial explosion
that the number of possibilities rap
expands exponentially technically with
the number of
the number of things you're considering
and
uh it can easily rapidly outstrip these
these billions of thoughts that we're
talking about so
we we definitely uh cannot by brute
force
master complex situations and
or think about think of all the
possibilities in complex situations i
mean you know
even even something as relatively simple
as chess
is still something that human beings
can't comprehend completely even the
best players lose
still sometimes lose and they
consistently lose to computers these
days
uh and in computer science there's a
concept of
np complete so large classes of problems
when you scale them up beyond
a few individuals become intractable
and so that in that sense uh the world
is inexhaustible
but and that makes it beautiful that we
can make uh
any laws that generalize
efficiently and well can compress all of
that
combinatorial complexity just like a
simple rule that that itself is
beautiful
it's a happy situation and i i think
that that we can
find general principles of
sort of of the operating system that
are comprehensible simple extremely
powerful
and let us control things uh very well
and and ask profound questions
and on the other hand that the world is
going to be inexhaustible
that once we start asking about
relationships and how they evolve
and social interactions and the the
the we'll never have a theory of
everything in any meaningful sense
because
of everything everything truly
everything is
uh can i ask you about the big bang uh
so we talked about the space and time
are really big
but then and we humans give a lot of
meaning to the word space
and time in our in our like daily lives
but then can we talk about this moment
of beginning
and how we're supposed to think about it
that at the moment the big bang
everything was uh
what like infinitely small and then it
just
blew up we have to be careful here
because there's a
there's a common misconception that
the big that the big bang is like the
explosion of a bomb in empty space
that that uh fills up the surrounding
place
it is space it is yeah as we understand
it
it's the fact it's the the fact or the
hypothesis but
well supported up to a point that that
that everywhere in the whole universe
early in the history uh matter came
together into a very hot
very dense if you run it backwards in
time
matter comes together into a very hot
very dense and yet very homogeneous
plasma of all the different kinds of
elementary particles and quarks and
anti-quarks and gluons and photons and
electrons and anti-electrons everything
you know all of that stuff
like really hot really really
really hot we're talking about uh way
way hotter than the surface of the sun
uh you know well in fact if you
take the equations as we as they come
the the prediction is that the
temperature just goes to infinity but
then the equations
uh break down we don't you know we don't
don't really
with their various the equations become
infinity equals infinity so they don't
feel
that it's called a singularity we don't
really know uh this is running the
equations backwards so you can't really
get a sensible
idea of what happened before the big
bang we don't you know so
we need different equations to address
the very earliest
moments uh that uh
but so things were hotter and denser we
don't
really know why things started out that
way
we do we have a lot of evidence that
they did start out that way
uh but since most of the
uh you know we don't get to visit there
and do controlled experiments most most
of the
most of the record is is very very
processed and
we have to we have to use uh very
uh subtle techniques and powerful
instruments to
to get information that has survived
get closer and closer to the get closer
and closer to
the the beginning of things and
what's revealed there is that uh
as i said there what there undoubtedly
was a period when
everything in the universe that we have
been able to look at
and understand and that's consistent
with everything
is uh um
the was in a condition where it was much
much hotter
and much much denser but still obeying
the laws of physics as we know them
today
and and then you start with that so all
the matter is in equilibrium
uh and then with small quantum
fluctuations and run it forward
and then it produces in at least in
broad
strokes the universe we see around us
today
do you think we'll ever be able to with
the tools of physics
with the way sciences with the way the
human mind is we'll ever be able to get
to the moment of the big bang in our
understanding
or even the moment before the big bang
can we understand what happened before
the big bang i'm
i'm optimistic both that we'll
be able to uh measure more
so observe more and that we'll be able
to figure out more
so uh they're very very tangible
prospects
for uh observing the
extremely early universe so much even
much earlier than we can
observe now uh through looking at
gravitational waves
gravitational waves since they interact
so weakly
with ordinary matter uh
sort of send an un a minimally processed
signal from the big bang it's a very
weak
signal because it's traveled a long way
and diffused over long spaces
but uh but people are gearing up to try
to detect
gravitational waves that could have come
from the early universe yeah ligo's
incredible engineering project is the
most sensitive
precise yes devices on earth
the fact that humans can build something
like that is uh
truly awe-inspiring from an engineering
perspective right
and but these gravitational waves from
the early universe would probably be
of a much longer wavelength than lyco is
capable of
sensing so there's a beautiful
project uh that's contemplated
to put lasers in different parts
different locations in the solar system
you know we really really separated by
uh solar system scale differences like
artificial planets or moons
in different places and and see the tiny
motions of those relative to one another
as a signal of
of radiation from the big bang we can
also maybe
indirectly see the imprint of
gravitational waves from the early
universe
on uh the photons the the microwave
background radiation
that that is our present way of of
seeing
into the earliest universe but those
those photons
interact much more strongly with matter
they're much more strongly processed so
they don't
give us directly such an unprocessed
view of the early universe of the very
early universe
but if gravitational waves leave some
imprint
on that as they move through uh
we could detect that too and people are
trying our
as we speak working very hard towards uh
towards that goal it's so exciting to
think about a sensor the size of a solar
system
like uh that would be a fantastic i mean
that would be a pinnacle
artifact of human endeavor to me it
would be
such uh such an inspiring thing
that just we want to know
and we go to these extraordinary lengths
of making
gigantic things that are also very
sophisticated because what you're trying
to do
you you have to understand how they move
you have to understand
uh the properties of light that that are
being used interference between light
and
you have to be able to make the light
with lasers and understand the quantum
theory and
get the timing exactly right you know
it's an extraordinary
endeavor involving all kinds of
knowledge from the very strong
very small to the very large and all in
the service of
uh curiosity and built on a grand scale
so yeah
if we did that i love that you're
inspired both by by the power of theory
and the power of experiments so this is
the both both i think are
exceptionally impressive that the human
mind can come up with theories
that give us a peek into how the
universe works but also
construct tools that are way bigger than
uh
the the evolutionary origins we came
from right
and by the way you know the fact that we
can design those things and they work
yeah is an extraordinary demonstration
that we really do
understand a lot and then
in some ways and it's our ability to
answer
questions that also leads us to be able
to address more ambitious questions
so you mentioned that at the at the big
bang
in the early days things are pretty
homogeneous
yes but uh here we are sitting on earth
to uh hairless apes you could say
with microphones in talking about the
brief history of things you said it's
much harder to describe sweden than it
is
um the universe so there's a lot of
complexity
there's a lot of interesting details
here so how does this complexity come to
be do you think
it seems like there's these pockets yeah
we don't know how rare of like
uh we're hairless apes just emerge yeah
and then they came from the initial soup
that was homogeneous
was that uh yeah accident
well we understand there we understand
in broad
outlines how it could happen
we certainly don't understand why it
happened exactly and the way it did or
but but uh or you know
there are certainly open questions about
the origins of life and how inevitable
the emergence of intelligence was and
and how that happened
but uh in the very broadest terms
uh the universe early on
was quite homogeneous but not completely
homogeneous
there are there were part in 10 000
fluctuations in density within this
primordial plasma and
uh as time goes on
there's an instability which causes
those density contrasts
to increase there's a gravitational
instability where it's denser
the gravitational attractions are
stronger and so that brings in more
matter and it gets even denser
and so on and so on so so there's a
natural
tendency of matter to clump because of
gravitational interactions
and then the equations get complicated
when you have lots of things
clumping together uh then you know then
then we know what the laws are but we
have to to a certain extent wave our
hands about what what
what happens but uh the basic
understanding of chemistry says that if
things
and and the physics of radiation tells
us that if
as things start to clump together they
can radiate give off some
energy so they don't just they slow down
they as a result they lose energy they
conglomerate together
cool down form things like stars form
things like planets
and so in broad terms there's no mystery
there's
that that's what the scenario that's
what the equations tell
you should happen but because
it's a process involving many many
fundament individual units uh
the the the application of the laws that
govern
individual units to these things is is
very delicate uh you know
computationally very difficult
and more profoundly uh the equations
have this probability of chaos or
sensitivity to initial conditions which
tells you
tiny differences in the initial state
can lead to enormous differences
in the subsequent behavior so so
physics fundamental physics at some
point says
okay chemists biologists this is your
problem
and and uh and then
again in broad terms we know how
uh it's conceivable that that the
humans and things like that can can uh
that how complex structure can emerge
it's a matter of uh having
the right kind of temperature and the
right kind of stuff
so you need you need to be able to make
chemical bonds that are reasonably
stable and
be able to make complex structures and
we're very fortunate that carbon has
this
ability to make uh backbones and
elaborate branchings and things so you
can get complex things that we call
biochemistry
and and yet the bonds can be broken a
little bit with the help of
energetic injections from the sun so you
have to have
both the possibility of changing but
also the possible
useful degree of stability and we know
at that
very very broad level
physics can tell you that it's
conceivable yeah if you want to know
what actually
what what's what what really happened
what really can happen then you have to
work a bit to
go to chemistry if you have if you want
to know what actually happened
then you really have to consult the
fossil record in biologists and so
so uh but but it's it so these
these ways of addressing the issue
are complementary in a sense they but
they uh
they uh they use different kinds of
concepts they use different
uh languages and they address different
kinds of questions but
they're they're not inconsistent they're
just
complimentary it's kind of interesting
to think about
those early fluctuations as our
earliest ancestors yes that's right so
it's far it's amazing to think that uh
you know this is
the modern answer to the uh
or the modern version of uh
the what the hindu philosophers had that
art thou
if you ask what okay that those those
little quantum fluctuations in the early
universe
are the seeds out of which uh complexity
including uh plausibly humans really
evolve you don't need anything else that
brings up the question
of uh asking for a friend here if
there's
uh you know other pockets of complexity
commonly called as uh alien intelligent
civilizations out there well we don't
know for sure but i
i have a strong suspicion that the
answer is yes because
the uh the one
case we do have at hand to study
here on earth uh we sort of know what
the conditions were that were helpful to
life the right kind of temperature the
right kind of star
that that keeps maintains that
temperature for a long time the liquid
environment of water
and once those conditions
emerged on earth which was roughly four
and a half billion years ago it wasn't
very long before
what we call life started to leave
relics
so we can find the
forms of life primitive forms of life
that are almost
as old as the earth itself in the sense
that once the earth
became reason was was returned from a
a a very hot boiling thing and cooled
off into a solid mass with
it with water uh life emerged very very
quickly so
so it seems that these general
conditions for life
uh are enough to to make it happen
uh relatively quickly now
the other lesson i would i think that
one can uh draw from this one example
it's dangerous to
the drug lessons from one example but
that's all we've got
uh and uh that that the emergence of
intelligent life is a different
issue altogether it uh that took a long
time
and seems to have been pretty contingent
uh the you know the the for a long time
well for most most of the history of
life
it was single-celled things
you know uh yes even multicellular life
only rose about 600 million years ago
so much after you know so and the the
uh and then
intelligence is kind of a luxury you
know if you think
uh many more kinds of creatures
have uh big stomachs
than big brains and in fact uh most most
most have no brains at all in any
reasonable sense
that that then uh and the dinosaurs
ruled for a long long time and some of
them were pretty smart but
they they were at best bird brains
because you know birds
came from the dinosaurs uh and
uh and it could have stayed that way you
know and and
then human and the emergence of humans
was very contingent and kind of a
very very recent development on
evolutionary time scales
and uh you can argue about the level of
human intelligence but it's you know i
think it's
that that's what we're talking about and
it's very it's very impressive and can
ask these kinds of questions and discuss
them intelligently
uh the uh so
i guess my my so this is a long-winded
answer or justification of
my feeling is that uh the
conditions for life
in some form are probably con
satisfied many many places around the
universe
even and even within our galaxy uh
i'm not so sure about the emergence of
intelligent life
or the emergence of technological uh
civilizations that that that seems
uh much more much more contingent and
special and
we might it's conceivable to me that
we're the only example
in the galaxy or although
yeah i don't know one way or the other i
i have different opinions on different
days of the week well one of the things
that worries me
in in uh in the spirit of being humble
that our particular kind of intelligence
is not very special so there's all kinds
of different intelligences
and even more broadly there could be
many different
kinds of life yes so the basic
definition and i just had
i think somebody that you know sarah
walker i just had a very long
conversation with her
about even just the very basic question
of trying to define
what is life from a physics perspective
yeah even that question within itself i
think one of the most fundamental
questions
in science and physics and everything is
just
trying to get a hold trying to get some
universal laws around the
ideas of what is life because that kind
of unlocks a bunch of things around
life intelligence consciousness all
those kinds of things
i agree with you in a sense but i think
that's a dangerous question because
the the answer can't be any more precise
than the question
and the uh the the question what is life
kind of assumes that we have a
definition of life and that it's a
natural phenomena that that can be
distinguished
but that really there are edge cases
like viruses and
uh some people would like to say that uh
electrons have consciousness and they
you know
so you can't if you really have fuzzy
concepts
it's uh it's very hard to to reach
precise kinds of scientific answers
but i think there's a very fruitful
question that's
adjacent to it which is has been pursued
in different forms
for quite a while and is now becoming
very sophisticated
in reaching in new directions and that
is
what are the states of matter that are
possible you know so
in high school or grade school you
learn about solid solids liquids and
gases but that really just scratches the
surface
of different ways that are
distinguishable that matter can
form into uh
macroscopically different meaningful
patterns that we call phases
and then there are precise definitions
of what we mean by phases of matter
but then uh and that have been worked
out fruitful
over the decades and we're discovering
new states of matter all the time
and kind of having to work at what we
mean by
matter we're discovering the
capabilities of matter
to organize in interesting ways
and uh
some of them like liquid crystals
are important ingredients of life our
cell membranes are liquid crystals
and that's very important to the way
they work
recently there's been a development in
where we're talking about
uh states of matter that not only
not that are not static but that have
dynamics that have that uh
have characteristic patterns not only in
space but in time
these are called time crystals and
that's that's been a development that's
just in the last decade or so it's
really
really flourishing uh and
so uh is there a state of matter that
cause or
group of states of matter that
corresponds to life
uh maybe but but the answer can't be any
more definite than the question
so i mean i i got to push back on the
the the quite
those are just words i mean i i i
disagree with you the
the the question points to a direction
the answer might be able to be to be
more precise than the question
because because uh just as you're saying
there
there's uh that we could be discovering
certain
characteristics and patterns that are
associated with a certain
type of matter macroscopically speaking
and that that we can then uh be able to
post facto say this is let's
sign the word life well kind of matter i
agree with that completely that that's
that's uh but that's so it's not a
disagreement
it's very frequent in physics that where
in science that
uh words that are in common use gets
get refined and reprocessed into
scientific terms that's happened for
things like force and
energy uh and
so we've in a way we we find out what
the useful definition
is uh or symmetry for instance
and the common usage may be quite
different from the scientific usage but
the scientific usage
is special and takes on a life of its
own and we find out what the
the useful version of it is
uh what the the fruitful version of it
is
so i do think so in that spirit
i think if we uh can
identify states of matter
that or linked states of matter
that can carry on processes of uh
self-reproduction and development
and information processing
we should say we we might be tempted to
classify those
as like things as life yeah well can i
ask you about the craziest one
which is uh the one we know
maybe least about which is consciousness
is it possible that there are certain
kinds of matter would be able to
classify
as um conscious meaning
like the so there's uh the pan cyclists
right with the philosophers who kind of
try to imply that uh all matter has some
degree of consciousness and yeah you can
almost construct like a physics of
consciousness
yes do you um
again we're in such early days of this
but nevertheless it seems useful to talk
about is
is there some sense from a physical
perspective to make sense of
consciousness
again consciousness is uh
imprecise a very imprecise word and
loaded with
uh connotations that i think we should
we
don't want to start a scientific
analysis with that i don't think
uh it's often been
important in science to start with
simple cases
and work up uh consciousness i think
what
most people think of when you talk about
consciousness is okay
i'm what am i doing in the in the world
this is my experience i have a rich
experience rich inner life and
experience of
and uh where is that in the equations
and
i think that's a great question a great
great question and actually i think
i'm gearing up to spend part of the i
mean
to try to address that in coming years
one version of asking that question just
as you said now
is what is the simplest yeah formulation
of
that to study i think i think i'm much
more comfortable with the idea of
studying self-awareness
as opposed to consciousness because that
that sort of gets rid of the mystical
aura of the thing and self-awareness
is uh in simple you know the
i think uh contiguous at least
with ideas about feedback so
if you have a system that looks at its
own state
and responds to it that's a kind of
self-awareness
and more sophisticated versions could be
like
in information processing things
computers that look into their own
internal state and do something about it
and i think that could also be
done in neural nets this is called
recurrent neural nets which are hard to
understand and kind of a frontier of
the the uh uh so i think understanding
those
and gradually building up a kind of
uh profound
ability to un to uh
conceptualize different levels of
self-awareness what do you have to not
know and what do you have to know
and when do you know that you don't know
it or when do you know what do you think
you know that you don't really know
the the these uh i think uh
clarifying those issues when we clarify
those issues and get a rich theory
around uh self-awareness i think
the that will illuminate
the questions about consciousness in a
way that you know scratching your chin
and talking about qualia and blah blah
blah blah
is never going to do well i also have a
different approach to the whole thing so
there's from a robotics perspective you
can engineer
things that exhibit yes qualities of
consciousness without understanding
well well the how things work
and from that perspective you uh
it's like a back door like enter through
the psychology door
precisely the car yeah i think we're on
we're on the same wavelength here i
think that
and let me just add one comment which is
uh i think we should try to understand
consciousness as we experience it
uh in in as
in evolutionary terms and ask ourselves
why why does it happen this thing seems
useful
why is it useful why is it useful
i think we've got a conscious eye watch
here interesting quest thank you siri
okay yeah
get back i'll get back to you later uh
yeah uh um and i think what we're gonna
i'm i'm morally certain that what's
going to emerge from
analyzing recurrent neural nets and
robotic design and advanced computer
design
is that having this kind of
looking at the internal state
in a structured way that
that doesn't look at everything as guys
has it's encapsulated looks at highly
processed information and very selective
and makes
choices without knowing how they're made
there's so there'll also be an
unconscious
i think that that is going to be turn
out to be
really essential to doing efficient
information processing
and that's why it evolved
because it's it's it's it's helpful
in uh because brains come at a high cost
yeah so there has to be there has to be
a good why and there's a reason
yeah they're rare in evolution uh
you and uh big brains are rare in
evolution and they
they come at a big cost you mean if you
you they
they they have high metabolic
demands uh they require
you know very active lifestyle warm
bloodedness
and take away from the
ability to support metabolism of
digestion and so so it's it's uh
it comes at a high cost it has to it has
to pay back
yeah i think it has a lot of value in
social interaction so i
actually i'm spending the rest of the
day today and uh
with uh our friends uh
that are our legged friends in robotic
form at boston dynamics
and i think so
my probably biggest passion is human
robot interaction
and it seems that consciousness from the
perspective of the robot is very useful
to improve the human robot interaction
experience
the first the display of consciousness
but then to me there's a gray area
between the display of consciousness and
consciousness itself
if you think of consciousness from an
evolutionary perspective
it seems like a useful tool in human
communication so yes
um it's certainly well whatever
consciousness it
will turn out to be i think uh
addressing it
through its use yes and working up from
simple cases and also
working up from engineering experience
in trying to do efficient computation
including
efficient management of social
interactions
is going to really shed light on these
questions as i said in a way that
sort of musing abstractly about
consciousness never would
so as i mentioned i talked to sarah
walker and
first of all she says hi spoke very
highly of you one of her concerns about
physics
and physicists and humans is that
we may not fully understand the system
that we're inside of meaning
like there may be limits to the kind of
physics we do
in trying to understand the system of
which we're
part of so like the the observer
is also the observed in in that sense
it seems like the the um
our tools of understanding the world
i mean this is mostly centered around
the questions of what is life
trying to understand the patterns that
uh that are characteristic of life and
intelligence all those kinds of things
um we we're not we're not using the
right tools
because we're in the system is there is
there something that resonates with you
there almost well yeah yes we do have we
we have limitations of course uh
in the amount of information we can
process
uh on the other hand we can get help
from our silicon friends
and we uh we can get help from all kinds
of instruments that make up for for our
perceptual deficits
and uh we have to and we can use
at a conceptual level we can use
different kinds of concepts to address
different kinds of questions so i'm not
sure exactly
what problem she's talking about it's a
problem akin to
an organism living on a in a 2g plane
trying to understand
a three-dimensional world well we can do
that i mean you know we
in fact we you know for practical
purposes most of our experience
is two-dimensional it's hard to move
vertically and yet we've produced
conceptually a three-dimensional
symmetry and in fact
four-dimensional space-time uh so
you know by thinking in appropriate ways
and
using instruments and demand and getting
consistent accounts and rich accounts
we find out what concepts are uh
uh uh necessary and
uh i don't see any end in sight of the
process
or any uh show stoppers because
let me give you an example i mean for
instance uh
uh qcd our theory of the strong
interaction has
nice equations which i helped to
discover what's qcd
quantum chromodynamics so it's our
theory
of the strong interaction the
interaction that is responsible for
nuclear physics so it's the interaction
that governs how quarks and gluons
interact with each other and make
make protons and neutrons and all the
strong the
related particles and among many things
in physics it's one of the
four basic forces of nature as we
presently understand it
uh and
uh so we have beautiful equations which
we can
test in very special circumstances
uh uh using at high high energies at
accelerator so we're
certain that these equations are correct
you know prizes are given f