back to indexBrian Greene: Quantum Gravity, The Big Bang, Aliens, Death, and Meaning | Lex Fridman Podcast #232
link |
The following is a conversation with Brian Greene, theoretical physicist at Columbia
link |
and author of many amazing books on physics, including his latest, Until the End of Time,
link |
Mind, Matter, and Our Search for Meaning in an Evolving Universe.
link |
This is the Lex Friedman Podcast.
link |
To support it, please check out our sponsors in the description.
link |
And now, here's my conversation with Brian Greene.
link |
In your most recent book, Until the End of Time, you quote Bertrand Russell from a debate
link |
he had about God in 1948.
link |
So far, scientific evidence goes, the universe has crawled by slow stages to a somewhat pitiful
link |
result on this Earth, and is going to crawl by still more pitiful stages to a condition
link |
of universal death.
link |
If this is to be taken as evidence of purpose, I can only say that the purpose is one that
link |
does not appeal to me.
link |
I see no reason therefore to believe in any sort of God.
link |
That's quite a depressing statement.
link |
As you say, this is a bleak outlook on our universe and the emergence of human consciousness.
link |
So let me ask, what is the more hopeful perspective to take on this story?
link |
Well, I think the more hopeful perspective is to more fully understand what was driving
link |
Bertrand Russell to this perspective, and then to see it within a broader context.
link |
And really, that's in some sense what my book, Until the End of Time, is all about.
link |
But in brief, I would say that there's a lot of truth to what Bertrand Russell was saying
link |
Second law of thermodynamics, which is the underlying scientific idea that's driving
link |
this notion that everything's going to wither, decay, fall apart.
link |
Yeah, that's true.
link |
Second law of thermodynamics establishes that disorder, entropy, and aggregate is always
link |
on the rise, and that is indeed interpretable as disintegration and destruction over sufficiently
link |
But my view is, when you recognize how special that makes us, that we are these exquisitely
link |
ordered configurations of particles that only will last for a blink of an eye in cosmological
link |
time like terms, the fact that we're here and we can do what we do, to me, that's just
link |
really something that inspires gratitude and wonder and a sense of deep purpose by virtue
link |
of being these unique collections of entities that happen to rise up, look around, and try
link |
to figure out where we are and what the heck we should do with our time.
link |
So it's not that I would disagree with Bertrand Russell in terms of the basic physics and
link |
the basic unfolding, but I think it's really a matter of the slant that you take on what
link |
So maybe we'll skip around a bit, but let me ask the biggest possible question, then
link |
you said purpose, so what's the meaning of it all then?
link |
Is there a meaning to life that we can take from this?
link |
From this brief emergence of complexity that arises from simple things and then goes into
link |
a heat death that is, once again, returns to simple things as the march of the second
link |
law of thermodynamics goes on.
link |
I think there is, but I don't think it's a universal answer.
link |
And so I think throughout the ages, there has been a kind of quest for some final way
link |
of articulating meaning and purpose, whether it's God, whether it's love, whether it's
link |
I mean, many people put forward different ways of taking this question on.
link |
And there is no one right answer when you recognize deeply that the universe doesn't
link |
There is nothing out there that is the final answer.
link |
It's not as though we need a more powerful telescope and somehow if we can look deeply
link |
into the universe, all will become clear.
link |
In fact, the deeper we've looked, but literally and metaphorically, into the universe and
link |
into the structure of reality, the more it's become clear that we are just a momentary
link |
byproduct of laws of physics that don't have any emotional content.
link |
They don't have any intrinsic sense of meaning or purpose.
link |
And when you recognize that, you realize that searching for the universal for this kind
link |
of a question is a fool's errand.
link |
Every individual has the capacity to make their own meaning, to set their own purpose.
link |
And that's not some platitude.
link |
That is what we are, because there is no fundamental answer.
link |
It's what you make of it.
link |
And however much that may sound like a hallmark card, this really is the deep lesson of physics
link |
and science more generally over the past few hundred years.
link |
Well, there's some level where you can objectively say that whatever we've got going on here
link |
is kind of peculiar.
link |
It's kind of special in terms of complexity.
link |
And maybe you can even begin to measure it and come up with metrics where whatever we
link |
got going on on Earth, these interesting hierarchical complexities that form more and more sophisticated
link |
biological system, that seems kind of unique when you look at the entire universe.
link |
The observable part that we can see with our tools.
link |
So I have to ask, as you described in your book once again, Schrodinger wrote the book
link |
Based on a few lectures he gave in 1944.
link |
So let me ask the fundamental question here.
link |
This particular thing we got going on here, this pocket of complexity that emerged from
link |
such simple things.
link |
Yeah, it's a tough question.
link |
I asked that question even to Richard Dawkins once and I already have my preconceived notion,
link |
which he pretty much confirmed, which is if one could give an answer to that question
link |
that allows you to sort of draw a line in the sand between the not living and the living,
link |
then perhaps we would have the insight that we yearn for in trying to say what is so special
link |
But the fact of the matter is it's a continuum.
link |
There's a continuum from the things that we would typically call non living inanimate
link |
to the things that we obviously call animate and full of the currents of life.
link |
Somewhere in there, it is a question of the complexity of the structure, the ability of
link |
the structure to take in raw material from the environment and process it through a metabolism
link |
that allows the structure to extract energy and to release entropy to the wider environment.
link |
Somewhere in those collections of biological processes is the necessity or the necessary
link |
ingredients and processes for life, but drawing that line in the sand is not something that
link |
we're able to do, but I would agree with you.
link |
It's deeply peculiar, it may in fact be unique, but it may not.
link |
It could be that the universe is such that under fairly typical conditions, a star that's
link |
a well ordered source of low entropy energy, that's what the sun is, together with a planet
link |
being bathed by that low entropy energy, together with a surface that has enough of the raw
link |
constituents that we recognize are fairly commonplace result of supernova explosions
link |
where star spews forth the result of the nuclear furnace that is the core of a star.
link |
It could be that all you need are those fairly commonplace conditions and maybe life naturally
link |
Look, the James Webb Space Telescope is going up hopefully in December and one of the goals
link |
of that mission is to look at atmospheres around distant planets and perhaps come to
link |
some sense of how special or not life or life as we know it is in the universe.
link |
Which part of the story of life, let's stick to earth for a second, do you think is the
link |
If you were like a betting man, which part is the hardest to make happen?
link |
Is it the origin of life, again we haven't drawn the line of word, as you say, the line
link |
between a rock and a rabbit?
link |
That part, is it complex organisms like multi cellular organisms?
link |
Is it crawling out of the ocean where the fish somehow figured out how to crawl around?
link |
Is it then the us Homo sapiens as we like to think of ourselves special and intelligent?
link |
Or is it somewhere in between as you also talk about, again, very hard to know at which
link |
point this consciousness emerge?
link |
If you were to sort of took a survey and made bets about other earth like planets in the
link |
universe, where do you think they get stuck the most?
link |
Well, I would certainly see if we're going to go all the way to conscious beings like
link |
ourselves, I would put it at the onset of consciousness, which again, I think is a continuum
link |
I don't think it is something that you can draw the line in the sand.
link |
But there are obvious circumstances, there are obvious creatures such as ourselves where
link |
we do recognize a certain kind of self reflective conscious awareness.
link |
And if we think about what it would require for a system of living beings to acquire consciousness,
link |
I think that's probably the hardest part because look, take Earth and recognize that
link |
weren't for some singular event 65 million years ago where this large rock slams into
link |
planet Earth and wipes out the dinosaurs, maybe the dinosaurs would still rule the planet
link |
and they may well have not developed the kind of conscious awareness that we have.
link |
So for billions of years on this planet, there was life that didn't have the kind of conscious
link |
awareness that we have.
link |
And it was an accidental event in astrophysical history that allowed a mammalian species like
link |
us to ultimately be the end product.
link |
And so yeah, I could imagine there's a lot of life out there, but perhaps none of it's
link |
wondering what's the meaning of life or trying to make sense of it.
link |
Just going about its business of survival, which of course is the dominant activity that
link |
life on this planet has practiced.
link |
We are a rare exception to that.
link |
And I really appreciate that you lean into some of these unanswerable questions today.
link |
But so you think about consciousness, not as like a phase shift, the binary zero one.
link |
You think of it as a continuum that humans somehow are maybe some of the most conscious
link |
So I mean, people will dispute that.
link |
And it's a very hard argument.
link |
People will dispute that.
link |
Rocks probably will stay quiet on the matter.
link |
For the moment, they're waiting for their opportunity.
link |
But I agree that, look, even when you and I look at each other, I am not fully convinced
link |
that you're a conscious being.
link |
I mean, I think that you are.
link |
I mean, your behavior is such that that's the best explanation for what's going on.
link |
But of course, we're all in the position of only having direct awareness of our own conscious
link |
And therefore, when it comes to other creatures in the world, we're in a similar state of
link |
ignorance regarding what's actually happening inside of their head if they have a head.
link |
And so it's hard to know how singular we are.
link |
But I would say, based on the best available data and the best explanations that we can
link |
make, yeah, there is something special about us.
link |
I don't think that there are fish walking around and coming up with existentialism.
link |
I don't know that there are dogs walking around who've developed an understanding of the general
link |
theory of relativity.
link |
I mean, maybe we're wrong, but that seems the best explanation.
link |
What do you think is more special intelligence or consciousness?
link |
I think consciousness.
link |
And I think that there's a deep connection between these ideas.
link |
They are distinct, but they're deeply connected.
link |
But look, I mean, to me and to, of course, many philosophers actually coined a name for
link |
this, the hard problem of consciousness, David Chalmers and others.
link |
As a physicist, I look out at the world and I see its particles governed by physical law.
link |
You know, we've got electrons, we've got quarks that come in various flavors and so forth.
link |
We have a list of ingredients that science has revealed.
link |
And we have a list of laws that seemingly govern those ingredients.
link |
And nowhere in there is there even a hint that when you put those particles together
link |
in the right way, an inner world should turn on.
link |
And it's not only that there's no hint.
link |
I mean, it's ridiculous.
link |
How could it be that a thoughtless, passionless, emotionless particle, when grouped together
link |
with compatriots, somehow can yield something so deeply foreign to the nature of the ingredients
link |
So, so answering that question, I think is among the deepest and most difficult questions
link |
Do you think it is in fact a really hard problem or is it possible?
link |
I think you mentioned in your book that it's just like almost like a side effect.
link |
It's an emergent thing that's like, oh, it's nice.
link |
It's like a nice little feature.
link |
Well, I mean, when people use the phrase hard problem, I mean, they mean in a somewhat technical
link |
sense that it's trying to explain something that seems fundamentally unavailable to third
link |
party objective analysis, right?
link |
I'm the only one that can get inside my head and I can tell you a lot about what's happening
link |
inside my head right now is reflected in what I'm saying and you can try to deduce things
link |
about what's going on inside my head, but you don't have access to it in the way that
link |
And so it seems like a fundamentally different kind of problem from the ones that we have
link |
successfully dealt with over the course of centuries in science where we look at the
link |
motion of the moon, everybody can look, everybody can measure it.
link |
We look at, you know, the properties of hydrogen when you shine lasers on everybody can look
link |
at the data and understand it.
link |
And so it seems like a fundamentally different problem in that sense.
link |
It seems like it is hard relative to the others.
link |
But I do think ultimately that the explanation will be, as you recount, I think that a hundred
link |
years from now, or maybe it's a thousand, it's hard to predict the time scale for developments,
link |
but I think we'll get to a place where we'll look back and kind of smile at those folks
link |
in the 20th century and before 21st century and before who thought consciousness was so
link |
incredibly mysterious when the reality of it is, eh, it's just a thing that happens when
link |
particles come together.
link |
And however mysterious that feels right now, I think, for instance, when we start to build
link |
conscious systems, you know, things that you're more familiar with than I am, when we start
link |
to build these artificial systems and those systems report to us, I'm feeling sad, you
link |
know, I'm feeling anxious.
link |
Yeah, there's a world going on inside here.
link |
I think the mystery of consciousness will just begin to evaporate.
link |
Well, first of all, beautifully put, and I agree with you completely, just the way you
link |
said it, it'll begin to evaporate.
link |
I have built quite a few robots and have had them do emotional type things, and it's immediate
link |
that exactly what you're saying, this kind of mystery of consciousness starts to evaporate,
link |
that the kind of need to truly understand, to solve the hard problem of consciousness
link |
like disappears because, well, I don't really care if I understand or can solve the hard
link |
problem of consciousness.
link |
That thing sure as heck looks conscious, you know, I feel like that way when I interact
link |
with a dog, I don't need to solve the problem of consciousness to be able to interact and
link |
richly enjoy the experience with this other living being, obviously the same thing with
link |
I don't need to fully understand it.
link |
And there's some aspect, maybe this is a little bit too engineering focused, but there's some
link |
aspect in which it feels like consciousness is just a nice trick to help us communicate
link |
It sounds ridiculous to say, but sort of the ability to experience the world is very useful
link |
in a subjective sense, is very useful to put yourself in that world and to be able to describe
link |
the experience to others.
link |
It's a social and the merge, obviously animals, the sort of more primitive animals might experience
link |
consciousness in some more primitive way, but this kind of rich subjective experience
link |
that we think about as humans, I think it's probably deeply coupled with like language
link |
That resonates with my view as well.
link |
I mean, there's a scientist, maybe you've spoken to Michael Graziano from Princeton.
link |
He's developed ideas of consciousness that look, I don't think they solve the problem,
link |
but I think they do illuminate it in an interesting way where basically we are not aware of all
link |
the underlying physiochemical processes that make our brains and our inner worlds tick
link |
And because of that dissociation between sensation and the physics of it and the chemistry of
link |
it and the biology of it, it feels like our minds and our inner worlds are just untethered,
link |
like floating somewhere in this gray matter inside of our heads.
link |
And the way I like to think of it is like, look, if you were in a dark room and I had
link |
blown the dark paint on my fingers, so all you saw was my fingers dancing around, there
link |
would be something mysterious.
link |
How could those fingers be doing that?
link |
And then you turn on light and realize, oh, there's this arm underlying it, and that's
link |
the deep physical connection explains it all.
link |
And I think that's what we're missing, the deep physical connection between what's happening
link |
up here and what is responsible for it in a physical, chemical, biological way.
link |
And so to me, that at least gives me some understanding of why consciousness feels so
link |
mysterious because we are suppressing all of the underlying science that ultimately
link |
is responsible for it.
link |
And one day we will reveal that more fully, and I think that will help us tether this
link |
experience to something quite tangible in the world.
link |
I wonder if the mystery is an important component of enjoying something.
link |
So once we know how this thing works, maybe we will no longer enjoy this conversation.
link |
We'll seek other sources of enjoyment, but this is again from an engineering perspective.
link |
I wonder if the mystery is an important component.
link |
Well, have you ever seen this beautiful interview that Richard Feynman did, great Nobel Laureate
link |
physicist responsible for a lot of our understanding of quantum mechanics, quantum fielding and
link |
And he was in a conversation with an interviewer where he noted that some people feel like
link |
once the mystery is gone, once science explains something, the beauty goes away.
link |
The wonder of it goes away.
link |
And he was emphasizing in his response to that, he was like, no, that's not the right
link |
way of thinking about it.
link |
He says, look, when I look at a rose, he says, yeah, I can still deeply enjoy the aroma,
link |
the color, the texture.
link |
He says, but what I can do that you can't, if you're not a physicist, I can look more
link |
deeply and understand where the red comes from, where the aroma comes from, where the
link |
structure comes from.
link |
He says, that only augments my wonder.
link |
It only augments my experience.
link |
It doesn't flatten it or take away from it.
link |
So I sort of take that as a bit of a motto in some sense, that there is a wonder that
link |
comes from a kind of ignorance, and I don't mean that in a derogatory sense, but just
link |
So there is a wonder that comes from mystery.
link |
There's another kind of wonder that comes from knowing and deep knowing.
link |
And I think that kind of wonder has its own special character that in some ways can be
link |
I hope he's right.
link |
I hope you're right.
link |
But there's also, I remember he said something about like sizes and onion or something like
link |
You can peel back.
link |
You can keep peeling back.
link |
I mean, there is also, when you understand something, there's always a sense that there's
link |
more mystery to understand.
link |
You never get to the bottom of the mystery.
link |
But I think it's also different than, I don't think you can analogize, I say, to a magician.
link |
A magician does some trick.
link |
You learn how it's done.
link |
It's like, oh my God, that's ridiculous when you find.
link |
But nature is perhaps the best magician if you want to try to make the analogy there.
link |
Because when you peel things back and you understand how it is that things have color
link |
and you have electrons dancing from one orbital to another, emitting photons at very particular
link |
wavelengths that are described by these beautiful equations of quantum electrodynamics, part
link |
of which that Feynman developed, it gives you a greater sense of awe when the curtain
link |
is pulled back than what happens in other circumstances where it does flatten it completely.
link |
It's very possible then, say in physics, that we arrive at a theory of everything that unifies
link |
the laws of physics and has a very strong understanding of the fabric of reality.
link |
Even like from the Big Bang to today, it's possible that that understanding is only going
link |
to elevate our appreciation of this whole thing.
link |
Because it has so far, but the other side of it which you emphasize is, it's not like
link |
science somehow reaches an end.
link |
There are certain categories of questions that do reach an end.
link |
I think we one day will close the book on nature's ingredients and the fundamental laws.
link |
Now, we can't prove that.
link |
Maybe it goes on forever, smaller and smaller.
link |
Maybe they're deeper and deeper laws.
link |
But I don't think so.
link |
I think that there's going to be a collection of ingredients and a collection of basic laws.
link |
That chapter will close, but it's one chapter.
link |
Now, we take that knowledge and we try to understand how the world builds the structures
link |
that it does from planets to people to black holes to the possibility of other universes
link |
and every step of the way, the collection of questions that we don't know the answer
link |
So there's a deep sense of gratification from understanding certain qualities of the world.
link |
But I would say that if you take a ratio of what we understand to the things that we know
link |
that we don't yet understand, that ratio keeps getting smaller and smaller because the things
link |
that we know that we don't understand grows larger and larger.
link |
Do you have a hope that we solve that theory of everything puzzle in the next few decades?
link |
So there's been a bunch of attempts from string theory to all kinds of attempts at trying
link |
to solve quantum gravity or basically come up with a theory for quantum gravity.
link |
There's a lot of complexities to this.
link |
One for experimental validation, you have to observe effects that are very difficult
link |
So you have to build, like that's like an engineering challenge.
link |
And then there's the theory challenge, which is like, it seems very difficult to connect
link |
to the laws of gravity to quantum mechanics.
link |
Do you have a hope or are we hopelessly stuck?
link |
Well, I have to have a hope.
link |
I mean, it's in some sense, but I devote at least part of my professional life toward
link |
trying to make progress on.
link |
I'm glad you use the phrase quantum gravity.
link |
I'm not a great fan of the theory of everything phrase because it does make other scientists
link |
feel like if they're not working on this, what are they working on?
link |
And it's like, you know, there's not much left when you're talking about theory of everything.
link |
Phyology is just a small detail to figure out.
link |
So it is really trying to put gravity and quantum mechanics together.
link |
And since I was a college kid, I was deeply fascinated with gravity.
link |
And as I learned quantum mechanics, the notion of physicists being stumped and trying to
link |
blend them together, how could one not get fired up about maybe contributing something
link |
And so we've been on this, you know, I've been on this for 30 years since I was a student.
link |
We have made progress.
link |
You mentioned string theory is one possible scenario.
link |
String theory is a vibrant field of research that is making incredible progress.
link |
But we've not made progress on this issue of experimental verification validation, which
link |
as you know, it is a vital part of the story.
link |
So I would have hoped that by now we would have made contact with observation if you
link |
would have interviewed me back in the 80s when I was, you know, a wild, bright eyed
link |
kid trying to make headway, working 18 hours a day and this sort of stuff.
link |
I would have said, yeah, by 2021, yeah, we're going to know whether it's right or wrong.
link |
We'll have made contact.
link |
I would have said, look, there may be certain mathematical puzzles that we've got to work
link |
out, but we'll know enough to make contact with experiment that has not happened.
link |
On the other hand, if you would have interviewed me back then and asked me, will we be able
link |
to talk about detailed qualities of black holes and understand them at the level of
link |
detail that we actually, I would have said, no, I don't think that we're going to be
link |
Will we have an exact formulation of string theory in certain circumstances?
link |
No, I don't think we're going to have that and yet we do.
link |
So it's just to say you don't know where the progress is going to happen, but yes, I do
link |
hold out hope that maybe before I move on to wherever, I don't think there is an after,
link |
but I would love before I leave this earth to know the answer.
link |
But you know, science and the universe, it's not about pleasing any individual.
link |
And so we just press onward and we'll see where it goes.
link |
So in terms of string theory, if I just look from an outsider's perspective currently at
link |
the theoretical physics community, string theory is the theory was as a theory has been very
link |
popular for a few decades, but it has recently fallen out of favor, or at least there's been
link |
like, you know, it became more popular to kind of ask the question, is string theory
link |
really the answer?
link |
Where do you fall on this?
link |
Like how do you make sense of this puzzle?
link |
Why do you think it has fallen out of favor?
link |
Yeah, so I would actually challenge the statement that's fallen out of favor.
link |
I would say that any field of research when it's new and it's the bright, shiny bicycle
link |
that no one has yet seen on that block, yeah, it's going to attract attention and the news
link |
outlets are going to cover it and students are going to flock to it, sure.
link |
But as a field matures, it does shed those qualities because it's no longer as novel
link |
as it was when it was first introduced 30, 40 years ago, but you need to judge it by
link |
a different standard.
link |
You need to judge it by, is it making progress on foundational issues deepening our understanding
link |
And by that measure, string theory is scoring very high.
link |
Now at the same time, you also need to judge whether it makes contact with experiment,
link |
as we discussed before too, and on that measure, we're still challenged.
link |
So I would say that many string theories, myself included, are very sober about the theory.
link |
It has the tremendous progress that it had 30, 40 years ago that hasn't gone away, but
link |
we've become better equipped at assessing the long journey ahead.
link |
And that was something that we weren't particularly good at back, say, in the 80s.
link |
Look, when I was just starting out in the field, there was a sense of physics is about
link |
String theory is about to be the be all and end all final unified theory, and that will
link |
bring this chapter to a close.
link |
Now I have to say, I think it was more the younger physicists who were saying that.
link |
Some of them were seasoned, even if they were pro string theory at the time, I don't know
link |
if they were rolling their eyes, but they knew that was going to be a long, long journey.
link |
I think people like John Schwartz, one of the founders of string theory, Michael Green,
link |
no relation to me, founders of the theory, Edward Whitten, one of the main people driving
link |
the theory back then and today, I think they knew that we were in for a long haul.
link |
And that's the nature of science, quick hits that resolve everything, few and far between.
link |
And so if you were in for the quick solution to the big questions of the world, then you
link |
would have been disappointed.
link |
And I think there were people who were disappointed and moved on and work on other subjects.
link |
If we were in in the way that Einstein was in, for a lifetime of investigation to try
link |
to see what the answers to the deep questions would be, then I think string theory has been
link |
a rich source of material that has kept so many people deeply engaged in moving the frontier
link |
There's a few qualities about string theory, which are weird.
link |
I mean, a lot of physics is just weird and beautiful.
link |
So let me ask the question, what do you as most beautiful boss string theory?
link |
Well, what attracted me to the theory at the outset, beyond its putting gravity and quantum
link |
mechanics together, which I think is its true claim to fame, at least on paper, it's able
link |
What attracted me to here was the fact that it requires extra dimensions of space.
link |
And this was an idea that intrigued me in a very deep way, even before I really understood
link |
I somehow had, I mean, talk about sort of the emotional part of consciousness and the
link |
cognitive part in some, perhaps you call it strange and some strange emotional way.
link |
I was enamored with Einstein's general relativity, the idea of curved space and time before I
link |
really knew what it meant.
link |
It just spoke to me.
link |
I don't know how else to say it.
link |
And then when I subsequently learned that people had thought about more dimensions of
link |
space than we can see and how those extra dimensions would be vital to a deep understanding
link |
of the things that we do see in this world, four or five, six dimensions might explain
link |
why there are certain forces and particles and how they behave.
link |
To me, this was like amazing, utterly amazing.
link |
And then when I learned that string theory embraced all these ideas, embraced the general
link |
theory of relativity, embraced quantum mechanics, embraced the possibility of extra dimensions,
link |
then I was hooked.
link |
And so when I was a graduate student, we would just spend hours, we, I mean, a couple of
link |
other graduate students and myself who had sort of worked really well together, was at
link |
Oxford in England.
link |
We would work these enormous numbers of hours a day trying to understand the shapes of these
link |
extra dimensions, the geometry of them, what those geometrical shapes for the extra dimensions
link |
would imply for things that we see in the world around us.
link |
And it was a, it was a heady, heady time.
link |
And that kind of excitement has sort of filtered through over the decades, but I'd say that's
link |
really the, the part of the theory that I think really hooked me most strongly.
link |
How are we supposed to think about those extra dimensions?
link |
I was supposed to imagine actual physical reality or is this more in the space of mathematics
link |
that allows you to sort of come up with tricks to describe the four dimensional reality that
link |
we more directly perceive?
link |
No one really knows the answer, of course, but if I take the most straightforward approach
link |
to string theory, you really are imagining that these dimensions are there.
link |
I mean, just as you would say that the three space dimensions around us, you know, left,
link |
right, back, forth, up, down, yeah, we, they're real, they're here.
link |
We are immersed within those dimensions.
link |
These other dimensions are as real as these with the one difference being their shape
link |
and their size differs from the shape and size of the dimensions that we have direct
link |
access to through, through human experience.
link |
And one approach imagines that these extra dimensions are tightly coiled up, curled up,
link |
crushed together, if you will, into a beautiful geometrical form that's all around us, but
link |
just too small for us to detect with our eyes, too small for us to detect even with the most
link |
powerful equipment that we have.
link |
Nevertheless, according to the mathematics, the size and the shape of those extra dimensions
link |
leaves an imprint in the world that we do have access to.
link |
So one of the ways that we have hoped yet to achieve to make contact with experimental
link |
physics is to see a signature of those extra dimensions in places like the Large Hadron
link |
Collider in Geneva, Switzerland.
link |
And it hasn't happened yet.
link |
It doesn't mean it won't happen, but that would be a stunning moment in the history
link |
of the species if data that we acquired in these dimensions gives us kind of incontrovertible
link |
evidence that these dimensions are not the only dimensions.
link |
I mean, how mind blowing would that be?
link |
So with the Large Hadron Collider, it would be something in the movement of the particles
link |
or also the gravitational waves potentially be a place where you can detect signs of multiple
link |
dimensions like with something like LIGO, but much more accurate.
link |
In principle, all of these can work.
link |
So one of the experiments that we had high hopes for, but by high hopes, I'm actually
link |
One of the experiments that we imagined might in the best of all circumstances yield some
link |
We weren't with baited breath waiting for the result.
link |
We knew it was a long shot.
link |
When you slam protons together at very high speed of the Large Hadron Collider, if there
link |
are these extra dimensions and if they have the right form, and that's a hypothesis that
link |
may not be correct.
link |
But when the protons collide, they can create debris, energetic debris that can in some sense
link |
leave our dimensions and insert itself into the other dimensions.
link |
And the way you'd recognize that is there'd be more energy before the collision than after
link |
the collision because the debris would have taken energy away from the place where our
link |
detectors can detect it.
link |
So that's one real concrete way that you could find evidence for extra dimensions.
link |
But yeah, since extra dimensions are of space and gravity is something that exists within,
link |
in fact, is associated with the shape of space, gravitational waves in principle can provide
link |
a kind of cat scan of the extra dimensions if you had sufficient control over those processes.
link |
We don't yet, or perhaps one day we will.
link |
Does it make you sad a little bit?
link |
Are you looking out into the future, you mentioned Ed Whitton, that no Nobel Prizes have been
link |
given yet related to string theory?
link |
Do you think they will be?
link |
Do you think you have to have experimental validation or can a Nobel Prize be given?
link |
Which I don't think has been given for quite a long time for purely sort of theoretical
link |
Yeah, it certainly, as a matter of historical precedent, has been the case that those who
link |
win the prize have established, investigated, illuminated a demonstrably real quality of
link |
So gravitational waves, the prize was awarded after they were detected, not the mathematics
link |
of it, but the actual detection of it, you know, the Higgs particle, you know, it was
link |
an idea that came from the 1960s, Peter Higgs and others, in fact, and it wasn't until 2012,
link |
on July 4th, when the announcement came that this particle had been detected, the Large
link |
Hadron Collider, that people viewed it as eligible for the Nobel Prize.
link |
The idea was there, the math was there, but you needed to confirm it.
link |
Indeed, the prize ultimately was awarded, so I'm not surprised.
link |
In fact, I would have been surprised if a Nobel Prize had been awarded in the arena
link |
of string theory, because it's far too speculative right now, it's far too hypothetical.
link |
In fact, I am sympathetic to the view that it really shouldn't be called string theory.
link |
It degrades the word theory, because theory in science, of course, means the best available
link |
explanation for the things that we observe in the world, the things that we measure in
link |
experiments about the world, and string theory does not do that, at least not yet.
link |
So it really should be the string hypothesis, right?
link |
We're at an earlier stage of development, and that's not the kind of thing that Nobel
link |
Prizes should be awarded for.
link |
What do you think about the critics out there?
link |
Peter White, he's from Columbia too, I think, Sabine Havenstader.
link |
Is that a healthy thing, or should we sort of focus on sort of the optimism of these
link |
Yeah, it's actually a good way that you frame it, because I'm always somewhat repelled by
link |
views of the world that start from the negative, try to cut down an idea, try to say that's
link |
the wrong way of thinking about things, and so on.
link |
I'm much more drawn, maybe because I'm an optimist, I'm much more drawn to those who
link |
go out into the world with new ideas, and don't try to cut down one idea, but rather
link |
present another one that might be better.
link |
And so you make the first idea, maybe string the irrelevant, because you've come up with
link |
the better approach to the world.
link |
So do I think it's healthy look?
link |
I think having a wide range of views and perspectives is generally a healthy thing.
link |
I think it's good to have arguments within a subject in order that you stay fresh and
link |
you stay focused on the things that matter.
link |
But at the end of the day, I think it's a more vital contribution to give us something
link |
new rather than to criticize something that's there.
link |
Yeah, I'm totally with you.
link |
But it could be just the nature of being an optimist, and also just a love of engineering.
link |
It helps nobody by criticizing the rocket that somebody else built, just build a bigger,
link |
cheaper, better rocket.
link |
And that seems to be how human civilization can progress effectively.
link |
We've mentioned the second law of thermodynamics, I got to ask you about time, and do you think
link |
of time as emergent or fundamental to our universe?
link |
I like to think of it as emergent.
link |
I don't have a solid reason for that perspective.
link |
I have a lot of hints of reasons that some of which come out of string theory and quantum
link |
gravity that perhaps would be worth talking about.
link |
But what I would say is time is the most familiar quality of experience because there's nothing
link |
that takes place, that doesn't take place within an interval of time.
link |
And yet at the same time, it is perhaps the most mysterious quality of the world.
link |
So it's a wonderful confluence of the familiar and the deeply mysterious, all in one little
link |
If you were to ask me, what is time, I don't really know, I don't think anybody does.
link |
I can say what time gives us, it allows us the language for talking about change, it
link |
allows us to envision the events of the universe being spread out in this temporal timeline
link |
and in that way allows us to see the patterns that unfold within time.
link |
I mean, time allows us the structure and the organization to think about things in that
link |
kind of a progression.
link |
But what actually is it?
link |
I don't really know.
link |
And that's so strange because we can measure it.
link |
I mean, there are laboratories in the world that measure this thing called time to spectacular
link |
But if you go up to the folks and say, what is it that you're actually measuring, I don't
link |
know that they can really articulate the kind of answer that you would expect from those
link |
who are engineering a device that can measure something called time to that level of precision.
link |
So it's a very curious combination.
link |
What do you make of the one way feeling of causality?
link |
Is causality a thing or is that too just a human story that we put on top of this emergent
link |
phenomenon of time?
link |
I can give you my guess and my intuition about it.
link |
I do think that at the macroscopic level, if we're talking about sort of the human experience
link |
of time, I do think at the macroscopic level, there is a fundamental notion of causality
link |
that does emerge from a starting point that may not have causality built in.
link |
So I certainly would allow that at the deepest description of reality when we finally have
link |
that on the table, we may not see causality directly at that fundamental level.
link |
But I do believe that we will understand how to go from that fundamental level to a world
link |
where at the macroscopic level, there is this notion of A causes B, a notion that Einstein
link |
deeply embraced in his special theory of relativity, where he showed that time has qualities that
link |
we wouldn't expect based on experience.
link |
You and I, if we move relative to each other, our clocks tick off time at different rate.
link |
And our clocks is just a means of measuring this thing called time.
link |
So this is really time that we're talking about.
link |
Time for you and time for me are different if we're in relative motion.
link |
He then shows in the general theory of relativity that if we're experiencing different gravity,
link |
different gravitational fields are actually more precisely different gravitational potentials.
link |
Time will elapse for us at different rates.
link |
These are things that are astoundingly strange that give rise to a scientific notion of time
link |
So this is how far Einstein took us in wiping away the old understanding of time and injecting
link |
a new understanding of its quality.
link |
So there's so much about time that's counterintuitive, but I do not think that we're ever going
link |
to wipe away causality at the macroscopic level.
link |
At the macroscopic level, I mean, there's so many interesting things at the macroscopic
link |
level that may only exist at the macroscopic level.
link |
Like we already talked about consciousness that very well could be one of the things.
link |
You mentioned time travel.
link |
So I mean, according to Einstein and in general, what types of travel do you think our physical
link |
Well, certainly allows time travel to the future.
link |
And I'm not talking about the silly thing that you and I are now going into the future
link |
second by second by second.
link |
I'm talking about really the version that you see in Hollywood, at least in terms of
link |
its net effect whereby an individual can follow an Einsteinian strategy and propel themselves
link |
into the future in some sense more quickly.
link |
So if I wanted to see what's happening on planet Earth one million years from now, Einstein
link |
tells me how to get one million years from now, build a ship.
link |
I got to turn to guys who know how to build stuff.
link |
I can't do it like you build a ship that can go out into the universe near the speed of
link |
light, turn around and come back.
link |
Let's say it's a six month journey out a six month journey back.
link |
And Einstein tells me how fast I need to travel, how close to the speed of light I need to
link |
go so that when I step out of my ship, it will now be one million years into the future
link |
And this is not a controversial statement, right?
link |
This is not something where there's differences of opinion in the scientific community.
link |
Any scientist who knows anything about what Einstein taught us agrees with what I just
link |
It's commonplace, it's bread and butter physics.
link |
And so that kind of travel to the future is absolutely allowed by the laws of physics.
link |
There are engineering challenges, there are technological challenges.
link |
They're close to the speed of light part, yeah.
link |
Yeah, and there are even biological challenges, right?
link |
There are G forces that you're going to experience, you know, so there's all sorts of stuff embedded
link |
But those, I will call the details.
link |
And those details notwithstanding, the universe allows this kind of travel to the future.
link |
And if I could pause real quick, you can also, at the macro level, with biology extend the
link |
human lifespan to do a kind of travel forward in time.
link |
If you expand how long we live, that's a way to, from a perspective of an observer, a conscious
link |
observer that as a human being, you're essentially traveling forward in time by allowing yourself
link |
to live long enough to see the thing.
link |
So that's in the space of biology.
link |
What about traveling back in time?
link |
Yeah, that's the, that is a natural next question, especially if you're doing, if you're going
link |
on one of these journeys, is it a one way journey or can you come back?
link |
And the physics community doesn't speak with a unified voice on this as yet.
link |
But I would say that the dominant perspective is that you cannot get back.
link |
Now, having said that, there are proposals that serious people have written papers on
link |
regarding hypothetical ways in which you could travel to the past.
link |
And we've seen some of these, again, Hollywood loves to take the most sexy ideas of physics
link |
and build narratives around them.
link |
This idea of a wormhole, like Jodie Foster in contact went through a wormhole, a deep
link |
space nine star, I'm sure there are many other examples where these ideas that I've probably
link |
But with wormholes, there's at least a proposal of how you could take a wormhole tunnel through
link |
space time, manipulate the openings of the wormhole in such a way that the openings are
link |
no longer synchronous.
link |
They are out of sync relative to each other, which would mean one's ahead and one's behind,
link |
which means if you go through one direction, you travel to the future.
link |
If you go back, you travel to the past.
link |
Now, we don't know if there are wormholes in the world.
link |
But they're possible according to Einstein, correct?
link |
They are possible according to Einstein.
link |
But even Einstein was very quick to say, just because my math allows for something, doesn't
link |
I mean, he famously didn't even believe in black holes.
link |
Didn't believe in the Big Bang, right?
link |
And yet the black hole issue has really been settled now.
link |
We have radio telescopic photographs of the black hole in M87, it was in newspapers around
link |
the world just a couple of years ago.
link |
So it's just to say that just because it's in Einstein's math, it doesn't mean it's real.
link |
But yes, it is the case that wormholes are allowed by Einstein's equations and in principle,
link |
you can imagine putting electric charges on the openings of the wormhole, allowing you
link |
to tow them around in a manner that could yield this temporal asymmetry between them.
link |
Maybe you tow one of the mouths to the edge of a black hole.
link |
In principle, you can do this, slowing down the passage of time near that black hole.
link |
And then when you bring it back, it will be well out of sync with the other opening and
link |
therefore it could be a significant temporal gap between one and the other.
link |
But people who studied this in more detail question, could you ever keep a wormhole open
link |
assuming it does exist?
link |
Could you ever travel through a wormhole or would there be a requirement of some kind
link |
of exotic matter to prop it open that perhaps doesn't exist?
link |
So there are many, many issues that people have raised.
link |
And I would say that the general sentiment is that it's unlikely that this kind of scenario
link |
is going to survive our deeper understanding of physics when we finally have it.
link |
But that doesn't mean that the door is closed.
link |
So maybe there's a small possibility that this could one day be realized.
link |
That's such an interesting way to put it.
link |
This kind of scenario will not survive deeper understanding of physics.
link |
It's an interesting way to put it because it makes you wonder what kind of scenarios
link |
will be created by our deeper understanding of physics.
link |
Maybe, sorry to go crazy for a second.
link |
But if you have the panpsychism idea that consciousness permeates all matter, maybe
link |
traveling in that, whatever laws of physics the consciousness operates under, something
link |
like that, in that view of the universe, if we somehow are able to understand that part,
link |
maybe traveling is super easy.
link |
It does not follow the constraints of the speed of light.
link |
Something like this.
link |
So look, I have a definite degree of sympathy with the possibility that consciousness might
link |
be more than what we described earlier as just the byproduct of mindless particles.
link |
You just made the rock happy.
link |
So it isn't the approach that feels to me the most likely, but I see the logic.
link |
If you've got the puzzle, how to mindless particles build mind, one resolution might
link |
be the particles are not mindless.
link |
The particles have some kind of proto conscious quality.
link |
So there's something appealing about that straightforward solution to the puzzle.
link |
And if that's the case, if we do live in a panpsychist world where there's a degree
link |
of consciousness residing in everything in the world around us, then yes, I do think
link |
some interesting possibilities might emerge where maybe there's a way of communing with
link |
physical reality in a deeper way than we have so far.
link |
I mean, we as human beings, a vital part of our existence as human to human communication,
link |
contact, we live in social groups.
link |
And that's what it's allowed us to get to the place where we've gotten.
link |
Imagine that we have long missed that there's other consciousness out there and some kind
link |
of relationship or communion with that larger conscious possibility would take us to a different
link |
Now, do I, do I buy into this yet?
link |
I don't see any evidence for it, but do I have an open mind and allow for the possibility
link |
So if that's not the case, and you have these simple particles that at the macro level emerges
link |
some interesting stuff like consciousness.
link |
Another thing you write about in the, until the end of time book is the thing that it
link |
seems to emerge at the macro level is the feeling like there's a free will, like we
link |
decide to do stuff.
link |
And you have a really interesting take here, which is, no, there's not a free will.
link |
I'm just going to speak for you and then you can correct me.
link |
No, there's not a free will, but there is an experience of freedom.
link |
Which I really love.
link |
So where does the experience, where does freedom come from if we don't have any kind of physics
link |
And so the idea follows naturally from all that we've been talking about, let's make
link |
the assumption that all there is in the physical universe is stuff governed by laws.
link |
We may not have those laws, may not know what the fundamental stuff is yet, but everything
link |
we know in science points in the direction that it's physical stuff governed by universal
link |
And that being the case or that being the assumption, then you come to a particular
link |
collection of those ingredients called the human being.
link |
And that human being has particles that are fully governed by physical law.
link |
And when you then recognize it, every thought that we have, every action that we undertake
link |
is just the motion of particles.
link |
And I'm thinking thoughts right now, of course, at this level of description, it is the motion
link |
of particles cascading down various neurons inside of my head and so on.
link |
And every single one of those motions collectively and individually is fully governed by these
link |
laws that we perhaps don't have yet, but we imagine one day we will.
link |
That leaves no opportunity for any kind of freedom to break free from the constraint
link |
And that is the end of the story.
link |
So the traditional intuitive notion of free will that we're the ultimate authors of our
link |
actions, that we were the buckstops, that there is no antecedent, that is the cause
link |
for our decided to go left or right, choose vanilla or chocolate, live or die, that intuitive
link |
sensation does not have a basis in our understanding of the physical world.
link |
So that's the end of the free will of the traditional sort, but then your question is,
link |
what about this other kind of freedom I talk about?
link |
And the other kind of freedom, if you focus on it intently, I think is actually the true
link |
version of freedom that we feel.
link |
And that freedom is this, you look at inanimate objects in the world, rocks, bottles of water,
link |
whatever, they have a very limited behavioral repertoire.
link |
Their internal organization is too coarse for them to do very much, right?
link |
You have to, you try to have a conversation with a glass of water, you send sound waves,
link |
it doesn't do much.
link |
You may vibrate a little bit, but the repertoire of responses are incredibly limited.
link |
The difference between us and Iraq or a bottle of water is that our inner organization by
link |
virtue of eons of evolution by natural selection is so refined, so spectacularly ordered that
link |
we have a huge repertoire of behaviors that are finally attuned to stimuli from the external
link |
You ask me a question, that's a stimulus, and all of a sudden these particle processes
link |
go into action and this is the result, this answer that I'm giving you.
link |
So the freedom that we have is not from the control of physical law.
link |
The freedom that we have is from the constrained behavior that has long since governed inanimate
link |
We are liberated from the limited behavioral repertoire of rocks and bottles of water to
link |
have this broad spectrum of responses.
link |
Do we freely choose them?
link |
We do not, but yet we have them and we can marvel at those behaviors and that's the freedom
link |
The complexity and the breadth of that repertoire is where the freedom emerges.
link |
Is there something to be said about emergence?
link |
I don't know if you know, I've looked at much about objects that I seem to love way
link |
more than anyone else, which is cellular top, like game of life type of stuff.
link |
From simple things emerges beautiful complexity, and so that's that repertoire.
link |
It seems if you have enough stuff, just beautiful complexity emerges that sure as heck to our
link |
human eyes looks like there's consciousness there, there's free will, there's little objects
link |
moving about and making decisions.
link |
All of that, you can say it's anthropomorphization, but it sure as heck feels like there are organisms
link |
What is that emergence thing?
link |
Is that within the realm of physics to understand?
link |
Is it within the realm of poetry?
link |
Will that ever be understood by science?
link |
So here's the way that I think about it.
link |
So there are clearly qualities of the world that emerge on macroscopic scales, our sense
link |
of beauty, wonder, consciousness, all these kinds of qualities.
link |
Do I feel that they ultimately are explainable from the laws of physics?
link |
There is nothing that's not ultimately explainable with the laws of physics from this physicalist
link |
perspective, which is what I take.
link |
So you got the particles, you got the laws, and you have things that emerge from the choreographed
link |
motions of those particles.
link |
But is that the best language for talking about these emergent qualities?
link |
If I was to take something even more mundane, like a baseball flying through the air, if
link |
I was to describe it in terms of the quarks and the electrons, I'd give you this mountain
link |
of data with 10 to the 28 particles and all of their coordinates in space as a function
link |
I hand you this mountain of data, and you're like, I don't know what this is.
link |
And then if you really were clevering, looking, oh, it's a baseball just described in the least
link |
economical way possible.
link |
It is much more useful and insightful to talk about the baseball flying through the air.
link |
Similarly, there are things at the macroscopic level, like human experience and human emotion
link |
and human action and the sensation of free will that we undeniably all have, even if
link |
it itself doesn't have a basis in our understanding of the physical world.
link |
It's useful to talk about things in this very human language.
link |
And so yes, it's vital to talk about things in the poetic language of human experience,
link |
but do not lose sight of the fact.
link |
And some people do.
link |
They say, oh, it's just an emergent phenomenon.
link |
Don't lose sight of the fact that emergent phenomena are emerging from this deeper understanding
link |
that comes from the reductionist account of physical law.
link |
And there's a lot of insight to come from that, such as the freedom that you thought
link |
that you had, the freedom of will that you thought you had.
link |
It doesn't have a basis in that reductionist account, so it's not real.
link |
So speaking of the poetry of human experience, you mentioned the images of the black holes.
link |
How does it make you feel a few years ago when that first image came out?
link |
It's truly amazing, a sense of, well, I guess the feeling was both amazing and there was
link |
a little sense of jealousy is not quite the right word, but a sense of longing.
link |
Yeah, I think that's a better word because here's a subject that started with Einstein
link |
back in 1915, writes down the equations of the general theory of relativity.
link |
And then there are scores of individuals over the decades, starting with people like Carl
link |
Schwartzschild who analyze the equation and see the possibility of black holes.
link |
People develop these ideas, John Wheeler, all these greats of physics.
link |
It's still a hypothetical subject.
link |
It gets closer to reality through observations of the center of our galaxy, stars whipping
link |
around in a manner that could only really be explained by there being a black hole in
link |
the center of our galaxy, but it was still indirect to actually have a direct image that
link |
What a beautiful arc, narrative arc from the theoretical to the absolutely established.
link |
And that's what we hope will happen with other areas.
link |
For instance, string theory, right, I mean, wholly mathematical subject at the outset
link |
and still pretty much a wholly mathematical subject today, yeah, do we long for that image
link |
where we can look at it and say, string, it's real, maybe, you know, I mean, how thrilling,
link |
how thrilling to be part of that journey, to be part of that step that moves things
link |
from the abstract to the concrete.
link |
Yeah, so like the image of the DNA, the early images of the DNA, for example, but there
link |
is something special.
link |
So the problem with strings is they're tiny, so it's harder to take a picture in the following
link |
When you think of a black hole, I mean, you have a swirl of, I guess, what is, I don't
link |
even know, it's dust, whatever, light.
link |
A creating onto the event horizon.
link |
And then there's darkness, yeah, center, and you just imagine, so that picture in
link |
particular, I guess, is of a gigantic black hole, so you just, I mean, it's terrifying.
link |
Billions of times the mass of the sun.
link |
Yeah, so it's both exciting and terrifying.
link |
I mean, I don't know where you fall in the spectrum.
link |
I think it's exciting at first, like the longer I think about it, every time I think about
link |
it, the more terrifying it becomes.
link |
So it always starts exciting, and then it goes to terrifying.
link |
And both are feelings, very human feelings that I appreciate.
link |
It's like terrified awe, how it's still beautiful.
link |
That's a good way of saying it.
link |
And I think I kind of share that reaction, because there is a way in which when you work
link |
on this subject, like all the time, I teach it, I teach about black holes, write the equations
link |
on the blackboard, the ideas reside in a very cognitive, I don't know, mathematical portion
link |
of the brain, or at least for me.
link |
And it's only when you sit down, and it's quiet, and you start to contemplate, wait,
link |
wait, wait, this isn't just like a mathematical game.
link |
There are these monsters out there.
link |
Now I don't, not in a sense of I fear for my life, but it's a sense of how extraordinary
link |
And so it is breathtaking.
link |
How powerful nature is.
link |
Yeah, how stupendously powerful nature is.
link |
And so there is a deep sense of humility that I think this instills if you really allow
link |
the ideas to sink in.
link |
Well I have to ask about the most stupendously powerful thing to have ever happened in our
link |
universe, which is the Big Bang.
link |
What's up with the Big Bang?
link |
So we can, I mean, with gravitational waves, the hope is, you have more and more accurate
link |
measurements of the gravitational waves, you can crawl back further and further back in
link |
time towards the Big Bang.
link |
Do you have a hope that we'll be able to understand the early spark that created our universe?
link |
You know, that and the deep interior of a black hole are I think the biggest mysteries
link |
that we hope the melding of quantum mechanics and gravity will reveal, will illuminate.
link |
And you know, what question could be more captivating than why is there something rather
link |
than nothing, right?
link |
Why is there a universe at all?
link |
And will the theories that we're developing take us to an answer to that?
link |
Even if we truly knew what the Big Bang is, and that's a big question of its own, right,
link |
one would still be left with the question, well, okay, so you've explained the process
link |
by which a tiny nugget of a universe, a kind of nugget of space time can undergo some kind
link |
of growth to yield the world around us.
link |
But presumably in that explanation, you're going to involve mathematics and some ingredients
link |
like quantum fields or matter or energy or something.
link |
Where did that stuff come from?
link |
You know, can we get to that level of explanation?
link |
I don't know, but it is remarkable that if you ask what happened a millionth of a second
link |
after the Big Bang, it's not really that controversial any longer, right?
link |
Even though there's a lot of argument in the field, and it's very heated right now, I should
link |
say, regarding what is the right theory of the Big Bang?
link |
What is the right theory of early universe cosmology, where I mean early, much earlier
link |
than a millionth of a second, a lot of dissent, a lot of heated arguments about that.
link |
Yeah, right, exactly.
link |
But you go like a millionth of a second after that, and we're a pretty firm ground.
link |
Isn't that amazing, right?
link |
To understand what happened from that point forward, but to go back is controversial.
link |
So there is this theory called inflationary cosmology, which I would say has been the
link |
dominant paradigm since early 1980s.
link |
So what does that mean?
link |
Roughly 40 years now, it's been the dominant cosmological paradigm, and it makes use of
link |
a curious feature of Einstein's general theory of relativity, his theory of gravity, where
link |
Einstein shows us mathematically that gravity can not only be attractive, you know, the
link |
kind of gravity that we're used to, things pulled together, but it can also be repulsive.
link |
And that fact is then leveraged by people like Alan Gooth and Andre Linday, and at
link |
the time Paul Steinhard and Andreas Halbrecht and others, to say, okay, if we had a little
link |
nugget in the earlier universe, which was filled with the stuff that yields this repulsive
link |
gravity, well, that would have blown everything apart, it would cause everything to swell.
link |
Beautiful explanation for what the bang in the big bang was.
link |
And then people mathematically analyze the consequences of this idea, and they make predictions
link |
for tiny temperature differences across the night sky that in principle could be measured.
link |
You send up balloons, you send up satellites with very refined thermometers, and they measured
link |
the temperature of the night sky, and the statistical distribution of the temperature
link |
differences agrees with the mathematical predictions.
link |
I mean, you just sort of have to stand in awe.
link |
So you think, aha, the theory has been established.
link |
But scientists are an incredibly skeptical bunch.
link |
And some scientists, including one of the people who helped develop the theory at the
link |
outset, Paul Steinhard, comes along and says, well, yeah, it's done, this theory's done
link |
pretty well so far, but there are aspects of this theory that are making me lose confidence.
link |
For instance, this theory seems to suggest that there might be other universes.
link |
Like how do you make sense of a theory that suggests other universes, or there are others
link |
who come along and say this theory seems to talk about length scales that are minuscule
link |
even by the so called Planck length, the sort of shortest length that we can imagine making
link |
sense of in a theory of quantum gravity.
link |
How do you make sense of that?
link |
And so on and so forth, they develop a list of things that they consider to be chinks
link |
in the inflationary cosmological theories armor.
link |
And they develop other ideas, which they claim yield the same predictions as inflationary
link |
cosmology for those temperature differences across space, but don't suffer from these
link |
And then the inflationary cosmology folks say, no, no, no, hang on, your theory suffers from
link |
different problems.
link |
And so the arguments goes, it's a healthy debate.
link |
Talk about real debates in science.
link |
So when you ask what's up with the big bang, I don't know right now.
link |
If you would have asked me five years ago, maybe even less than that three or four years
link |
ago, I've said, look, inflationary cosmology has some issues.
link |
But the package of explanations it provides is so potent.
link |
And the issues that beset it are seemingly solvable to me that I would imagine it's going
link |
to, in the end, win out.
link |
I would still say that today, but I wouldn't say it as loudly.
link |
I wouldn't say it as confidently.
link |
I think it's worth thinking about alternate ideas.
link |
And it could be the case that the paradigm at some point shifts.
link |
Does dark matter and dark energy fit into the shifting of the explanations for those?
link |
And so dark energy in the inflationary theory is kind of a big mystery.
link |
So dark energy is the observational realization in the last 20 years that not only is the
link |
universe expanding, it's expanding ever more quickly.
link |
Something is still pushing things outward.
link |
And the explanation is that there's like a residual version of the repulsive gravity
link |
from the early universe.
link |
But it's such a strange number.
link |
When you write that amount of dark energy using the relevant units in a theory of quantum
link |
gravity, it's a decimal point followed by like 120 zeros and then a one.
link |
We're not used to those kinds of numbers in physics.
link |
We're used to a half, one, pi, E squared to two.
link |
Those are the kinds of fundamental numbers that emerge in our explanations of the world.
link |
And we look at this bizarre number, decimal point, all these zeros and one, we say, something's
link |
Like where would that number have come from?
link |
And now there are people who suggest resolution to it.
link |
So it's not like we're totally in the dark on it.
link |
But those people like Paul Steinhard who have alternate cosmological theories, cyclic cosmologies,
link |
as they call it, claim that they have a more natural explanation of the dark energy that
link |
it naturally feeds into a cyclical process that is their cosmological paradigm.
link |
So yeah, if the cosmology should change, it's conceivable our view of dark energy may change
link |
from deeply mysterious to deeply integrated into a different paradigm.
link |
I think it's Roger Peneros that think that information can bleed through from before
link |
the Big Bang to after the Big Bang.
link |
Is the Big Bang like a full erasure of the hard drive or is there some information that
link |
could bleed through?
link |
I mean, so Roger is among the most creative thinkers of the last 100 years, rightly won
link |
the Nobel Prize for his insights into singularities in space time that we know to afflict our
link |
mathematical solutions of black holes in the Big Bang and so forth and he has an enormously
link |
fertile imagination and I mean that in the most positive sense.
link |
So he has put forward this idea, this conformal cyclic cosmology, I think is the official
link |
title although I could be getting that wrong.
link |
I can't say that I've studied it.
link |
I have seen lectures on it.
link |
I don't find it convincing as yet.
link |
It feels like it's being built to find a solution as opposed to sort of more naturally
link |
emerging, maybe Roger would say otherwise and I don't mean to in any way cast aspersions
link |
It's vital and interesting and people are thinking about it.
link |
I don't consider it as close a competitor to say the inflationary theory as for instance
link |
the stuff that Paul Steinhardt has put forward but again, you've got to keep an open mind
link |
in this business when there's so much that we don't yet understand.
link |
I mean it is wild to think that information could survive something like that just like
link |
it is wild to imagine that information could escape a black hole for example or it just
link |
seems like by construction these things are supposed to not bleed out anything.
link |
But one of the challenges in all these theories is when we talk about a singularity, has this
link |
real sexy term the singularity, but a singularity is in more ordinary language, a physical system
link |
where the mathematics breaks down, it's nonsensical, it's like taking one divided by zero you put
link |
that into a calculator and it says E error, it does not make sense, doesn't compute and
link |
so it's very hard to make definitive statements about things like the Big Bang or about black
link |
holes until we cure the mathematical singularities and there are some who claim that in certain
link |
regimes the singularities have been cured, I don't by any mean think that there's consensus
link |
So when one talks about information sort of bleeding through the Big Bang, you've really
link |
got to make sure that the equations have no singularity.
link |
You talk about cyclic cosmology, you've got to make sure that the equations don't have
link |
any singularities as you go from say one cycle to the next.
link |
Now some of the proponents of these theories claim that they have resolved these issues.
link |
I don't think that there's a general sense that that is the case as yet, but it could
link |
be that look I, life is so short that I haven't had the time to deeply delve into all the
link |
mathematical intricacies of all the ideas that have moved forward, but did that I'd
link |
never do anything else.
link |
But that's what the issue is.
link |
And of course it's just math.
link |
There may be holes, there may be gaps in our understanding in the way we're modeling physical
link |
And in fact, when you said I was about to jump in and say modeling, but you got there first
link |
and it's exactly the right point, we're talking about the universe here, right?
link |
And how do you talk about the universe with a straight face mathematically?
link |
And the way you do it is you simplify, you throw away those characteristics of the universe
link |
that you don't think are vital to a full understanding.
link |
And so we're going to get to a point and people are starting to where we've got to go beyond
link |
those simplifications.
link |
And so cosmology has for a long time modeled the universe in the most simplest terms, homogeneous,
link |
It has just a few parameters that describe it, the average density of mass and energy
link |
We have to go beyond those simplifications and that will require putting these things
link |
We're not going to be able to do calculations there.
link |
So much as astrophysics has gone beyond many simplifications to now give really detailed
link |
simulations of star systems and galaxies and so forth, we're going to have to do that with
link |
cosmology and people are starting to do that today.
link |
Yeah, I've seen some interesting work on simulation, most simulation cosmology by the
link |
way is just awesome, but just like simulation of the early formation of our solar system
link |
to understand how the like the or cloud and just, I don't know, the whole of it, how
link |
earth came to be, how Jupiter just protects us and then there's like weird like moons
link |
and volcanoes and like modeling all of that, the formation of all of that is fascinating
link |
because that naturally leads the question of how does life emerge on these kinds of rocks?
link |
How does a rock become a rabbit?
link |
But speaking of models, there's an equation called the Drake equation, we were talking
link |
about life, have to ask when you're at the highest level first, when you look out there,
link |
how many alien civilizations do you think are out there?
link |
Well, it was zero, one or many.
link |
So if you say civilization, I would bring my number way down, it could be zero.
link |
If you talk about life, I think it could be many.
link |
As we were saying before, I think the move from life to consciousness, the kinds of beings
link |
that would build what we would recognize as a civilization, that may be extraordinarily
link |
As a kid, I love Star Trek, I just love the idea that we would be part of some universal
link |
community where look, experience on planet earth suggests it doesn't always go so well
link |
when groups who are separated try to come together and live in some larger collective,
link |
but again as an optimist, how amazing would it be to converse with an alien civilization
link |
and learn what they've figured out about physics and cosmology and compare notes and learn
link |
from each other in some wonderful way.
link |
I love that idea, but if you ask me the likelihood of it, I would err on saying it may be so
link |
improbable that the conditions conspire to allow life to move to this place of consciousness
link |
and it might be rare.
link |
It might be oversimplifying things, but just observing the power of the evolutionary process,
link |
I tend to believe and you read different theories of how we went, how homo sapiens evolved.
link |
It seems like the evolutionary process naturally leads to homo sapiens or creatures like that
link |
or much better than that.
link |
To me, there's several scary scenarios.
link |
The positive scenario is life itself is really difficult, so that origin of life is difficult.
link |
That's exciting for many reasons because we might be able to prove that wrong easily in
link |
the near term by finding life elsewhere.
link |
The scary thing to me is if life is easy and there's plenty of conscious intelligent civilizations
link |
out there and we have not obviously made contact, which means with intelligence and consciousness
link |
comes responsibility and ultimately destruction.
link |
With power comes great responsibility and then we end up destroying ourselves.
link |
That's the scariest.
link |
The positive version is that maybe we're being watched, there's a transition to where you
link |
don't want to ruin the primitive villages out there and so there's a protective layer
link |
around us that they're watching.
link |
Where do you, in these possible explanations to the Fermi paradox, why haven't we contacted
link |
I think the most straightforward explanation is that there aren't any.
link |
There are many other explanations too.
link |
You can't be dogmatic about things that are just sort of gut feel, but one of my favorite
link |
Twilight Zone episodes on it is one where this alien civilization finally comes to planet
link |
Earth and gives us this book that they really want us to have and to hold and it's in this
link |
foreign language, you don't understand, the cryptographers, they desperately try to decipher
link |
it as humans are going to visit this other alien planet and they're all sending back
link |
postcards, how wonderful it is and so forth and they finally decipher the title, it's
link |
to serve man and everyone's so thrilled that they're here to serve us, it all makes sense
link |
and then just as one of the final cryptographers is going on to the alien ship, his helper
link |
runs and says, I've deciphered the rest of the book, to serve man, it's a cookbook.
link |
So yeah, it's out of possibility, sure.
link |
And so could they be watching us and just sort of waiting for us to get to a mature
link |
enough level, I don't know, it strikes me, well, I think it'd be better to have this
link |
conversation after the James Webb telescope, I mean, I do think that if we look at the
link |
atmospheres of many planets, I mean, there's now an estimate now that there's on order
link |
of one planet per star on average, so we've long known that, you know, the galaxy hundreds
link |
of billions of stars, numbers of galaxies, hundreds of billions of galaxies that we're
link |
talking about, hundreds of billions of hundreds of billions of planets, oh my, you know, and
link |
if we start to survey some of these planets and one after the other after the other, we
link |
just sort of find no evidence for any of the biological markers, it could be, of course,
link |
maybe life takes a radically different form, it'd be hard to know that.
link |
But I think, you know, that would at least give us some insight on the life question,
link |
but I just don't see how we get insight on the civilization or consciousness question
link |
without, you know, the direct connection.
link |
And it strikes me that if consciousness is ubiquitous, let's say life is, I'm willing
link |
If consciousness is also ubiquitous, then I don't understand why they haven't been here
link |
or why there hasn't been such a decision because presumably they should be much further ahead
link |
How unlikely would it be that we're like, of all consciousness in the universe, we're
link |
the most advanced.
link |
That would be such a special place for human beings that it's hard for me to grant that
link |
as a likely possibility, rather, I think we're kind of running the mill.
link |
And there are many who are far more advanced than us.
link |
And I don't think that they would expend the energy to hide themselves.
link |
I don't think they care enough.
link |
And so, you see, that's actually what I believe that there's a very large number of civilizations
link |
that are far more advanced than us.
link |
But my sense is that humans are exceptionally limited, both in our direct sensory capabilities
link |
and our physics, our tools of sensing, that just like with the string theory and the multiple
link |
dimensions, we're just not, like, it's like, I honestly believe there could be stuff in
link |
front of our nose that we're just not seeing, because we're too dumb, too, too much hubris,
link |
and a bunch of stuff, and too ignorant to the fabric of reality, all of those things.
link |
We're young in terms of intelligence.
link |
But I guess what I'd say is, like, I'm on board with all of that as a real possibility,
link |
but then it does strike me that we are sufficiently able to observe the, look, we can look back
link |
to a fraction of the duration from here to there, just a fraction is left that we are
link |
So however young we are, we have been able to sort of pierce the universe, and it just
link |
strikes me that there would be some signature, but maybe that's coming, but look, having
link |
said that I do, look, I certainly note the fact that it's rare that I stoop down while
link |
walking in Manhattan and sort of dig up some ants in the bushes on the side of the street
link |
and talk to the ants, right, because it's just not interesting to me.
link |
So if we're like the ants on the cosmological landscape, then yeah, I can imagine that the
link |
super advanced aliens would be like, like, whoever, you know, but I feel like we're sufficiently
link |
advanced that there should be some signal signature of that, but maybe it's coming.
link |
I think the deeper fundamental problem between us and the ants is that we don't have a common
link |
It's not, it's not the interest.
link |
It's that we don't even have a common language.
link |
And so the alien civilizations don't even know how to, like we humans have convinced
link |
ourselves or especially because we developed the language and you talked about, you talk
link |
about the importance of language to the intelligence, but it makes you wonder like how very niche
link |
is that fan, like club that we've, like tribe we've created of language and linguistic type
link |
of systems that are very specific to our particular kinds of brains and we share ideas
link |
We're all super excited that we can understand the universe because we came up with some
link |
notation and math.
link |
I wonder if there's some totally other kinds of language that communicates on a different
link |
time scale with different, very different mechanisms in the space of information that's
link |
just, there's not everything.
link |
Everything is lost in translation.
link |
And it could well be as a look.
link |
I mean, I think part of the reason I go toward the possibility of the soul intelligence is
link |
there's a certain kind of romantic appeal to looking out in the cosmos and it's just
link |
quiet and it's just eternal silence.
link |
There's some, there's something that appeals to me at an emotional level that way.
link |
But yeah, I mean, nobody, nobody knows.
link |
And it's certainly conceivable that there's just a radical mismatch between the kinds
link |
of things that we are able to observe insensitive to versus the kinds of structures that permeate
link |
the universe in a manner that simply we're unable to detect.
link |
So if we are alone, that is exciting and one of the ways it's exciting is that it's up
link |
to us to become, to expand out into the universe, to permeate consciousness out into the universe.
link |
So that's where space exploration comes in.
link |
Let me ask you, as somebody who's a screen theorist, a physicist, do you think space
link |
exploration, colonizing space, is a physics or an engineering problem?
link |
What would you say?
link |
Yeah, I think it's fundamentally an engineering problem if we're not trying to do things like
link |
build wormholes the way they did, say an interstellar to get to a different place or trying to travel
link |
near the speed of light so that we would actually be able to traverse interstellar distances.
link |
I mean, without that, our colonization will happen at a very, very slow rate, right?
link |
But one of the beauties of relativity is if you do travel near the speed of light, you
link |
can actually go arbitrarily far in a human lifetime.
link |
People say, how's that possible?
link |
You can't go billions of light years.
link |
Well, you can actually because as you can do the speed of light, the way in which space
link |
and time change allows you to go, in principle, arbitrarily far.
link |
That's very exciting.
link |
But if we put that physics side of the issue in the manipulation space and time to the
link |
side, yeah, I think it's a deep engineering problem.
link |
How do you terraform other planets?
link |
How do you go beyond our local neighborhood, say, without using the ideas of relativity?
link |
So I think it's all quite exciting, and I think the idea is using solar sales that people
link |
have developed and trying to take that first step to Mars, I think that's a vital and valuable
link |
But yeah, I think these are fundamentally engineering challenges.
link |
Or extending the human lifespan through biology research or maybe reducing what it means to
link |
be a human being into information and uploading certain parts of it, maybe not all the full
link |
resolution of a human life, but maybe the essential things like the DNA and be able
link |
to reconstruct that human being.
link |
But I have to ask about Mars.
link |
Do you find the dream of human stepping on Mars, stepping foot first, but also colonizing
link |
Mars, one that's worth us fighting for?
link |
I mean, I think what we have long been, not always in the best way, is a species of explorers
link |
in the literal sense of traveling from one part of the world to another, or in the more
link |
metaphorical sense of trying to travel through our minds to the quantum realm or back to
link |
the big banger to the center of black holes.
link |
So I think that's fundamentally part of the human spirit.
link |
So I do think that's a vital part of our heritage brought forward into its next incarnation.
link |
That's who we are.
link |
Do you think there'll be a day in the future where a human being is born on Mars and has
link |
to learn about his or her human origins on Earth?
link |
Like they'll have to read in the book?
link |
Yeah, I don't think it'll be a book at that stage.
link |
It'll probably just be uploaded into the head or something, or imprinted into the DNA and
link |
then they just sort of sense it.
link |
But yeah, I think there's, well, look, the issue you raised before is the vital one
link |
Is it the case that any sufficiently advanced civilization destroys itself?
link |
Is that sort of a commonplace quality?
link |
I mean, that's the other potential answer to the Fermi paradox.
link |
Why aren't they here?
link |
Because by the time they got to the technological development where they could travel here,
link |
they blew themselves up.
link |
They destroyed themselves.
link |
And that's an unfortunate but not a hard to imagine possibility based on things that
link |
have happened here on planet Earth, but putting that to the side.
link |
I think that's the big obstacle, but putting that to the side, we will resolve the engineering
link |
And I should probably modify my answer from before.
link |
When you said is it engineering or physics, it's really both, right?
link |
So we will surmount the engineering challenges, and that will then make the physics challenges
link |
It'll make it relevant to figure out how to travel near this beat of light.
link |
It'll make it relevant to learn how to manipulate the shape of space time and so forth.
link |
So I think it's a multi stage process where it is engineering and ultimately physics.
link |
And if we stick around long enough, those are the kinds of challenges I think that we're
link |
ultimately going to surmount.
link |
And then the physics side is figuring out how to harness energy enough to travel outside
link |
the solar system, which seems like a heck of a difficult journey, but even Mars itself
link |
of, I don't know, maybe because I was born in the Soviet Union and was born with the,
link |
you know, looking up at the stars and that dream of like the highest of human achievement
link |
is ability to fly out there to, you know, to join the stars.
link |
I really liked the idea of going to Mars and not just stepping foot on Mars.
link |
It wasn't until maybe I'm misinformed, but for me personally, it wasn't until Elon Musk
link |
started talking about the colonization of Mars, did I realize like we humans can actually
link |
And the first of all, the importance of somebody saying that we can do these seemingly impossible
link |
things is immeasurable because, you know, the fact that he placed that into my mind
link |
and into the minds of millions of others, maybe hundreds of millions, maybe billions
link |
of others, young kids today, I mean, that that's going to make it a reality.
link |
I for some reason am deeply excited, even though my work in AI that echoes all of this,
link |
I'm excited by the idea that somebody would be born as what we're saying on Mars and sort
link |
of look up and be able to see with a telescope Earth and say, that's where I came from.
link |
I don't know that that idea scale to other planets, to other solar systems, yeah, that's
link |
It's hugely exciting.
link |
I think I'm absolutely right.
link |
I mean, the vital thing is to dream, right?
link |
I mean, and it sounds hackneyed, but it is so important for young kids for the next generation
link |
to think about the things that are seemingly impossible.
link |
I mean, that's what makes them possible.
link |
And this is one which is concrete enough.
link |
I mean, this is something that's going to happen soon in terms of actually going to Mars.
link |
And then the next step of establishing some presence, some semi permanent or permanent
link |
I mean, this is not something that's going to wait till the 25th century.
link |
I mean, this is something that's going to happen relatively soon.
link |
So I mean, it could well be in your lifetime, unlikely mine, but possibly in your lifetime
link |
that that kid will be born and have the experience that you described.
link |
So yeah, it's spectacularly exciting.
link |
And I actually, I would love to go on Mars and one of the early.
link |
It would have been one way.
link |
I'm happy to do one.
link |
There are so many stories out there that want to start that family.
link |
Let's go out to Mars.
link |
See, I have to tell you something.
link |
You talk about terror, thinking about like black holes.
link |
If I actually think about going to Mars and being on Mars and put myself in there fully,
link |
that's terror inducing.
link |
The idea of to be in this foreign world where you can't come back, where you've made this
link |
choice that can't be reversed, you know, at some point it may be.
link |
But in that guys, that to me carries a deep sense of terror.
link |
You know, I feel that sense of terror every time Kerak, Jack Kerak talked about this on
link |
the road is, you know, when you leave a place, if you're honest about it, like life is short.
link |
And when you leave a place, you move to a new place and you think of all the friends,
link |
maybe family, you're leaving behind as you drive over the hill.
link |
That really is goodbye.
link |
Like we sometimes don't think of it that way when we're moving.
link |
But that really is goodbye to that life, to the person you were, to the all the people.
link |
Maybe if it's close friends, you'll see that maybe 10, 15 more times in your life and that's
link |
And you're saying goodbye to all of that.
link |
And so in the same way, I see it as way more dramatic when you're flying away from Earth
link |
and it's like, it's goodbye to Dunkin Donuts and Starbucks and it's goodbye to whatever
link |
I don't know why I picked those, but some, all the things that are special to Earth,
link |
I suppose more what excites me about that kind of journey is it's a distinct contemplation
link |
of your mortality, acceptance of your mortality.
link |
You're saying just like when you take on any difficult journey, it's accepting that you're
link |
going to die one day and might as well do something truly exciting.
link |
I mean, I will, you know, I'm with you on that.
link |
I'm a strong believer that deep underneath human motivation is this, this terror of our
link |
There's this wonderful book that had a great influence on me called The Denial of Death
link |
by Ernest Becker and when you are aware of the ways in which our mortality influences
link |
our behaviors, it really does add a different slant, a different kind of color to the interpretation
link |
of human behavior.
link |
That book had a big influence on me as well.
link |
Oh, is that right?
link |
And a terror management theory and I, again, from an engineering perspective, I don't know
link |
how many people that book influenced because I talk to people about the fear of death and
link |
it doesn't seem to be that fundamental to their experience.
link |
And I don't think on the surface it's fundamental to my experience, but it seems like an awfully,
link |
in terms of talking about models and string theory and theories, in terms of theories
link |
of this macro experience of human life, it seems like a heck of a good theory that the
link |
fear of death is the kind of, is the warm at the core.
link |
Well, I mean, and the terror management theories that you make reference to, I mean, the, this
link |
is a group of psychologists, social psychologists who devise these very clever experiments,
link |
real world experiments with real people, where you can directly measure the hidden influence
link |
of the recognition of our own mortality.
link |
I mean, they've done these experiments where they have group of people, a group of people,
link |
B, and the only difference between the two groups is that group B, they somehow reminded
link |
them in some subtle way of their own mortality.
link |
Sometimes it's nothing more than interviewing them with a funeral home across the street,
link |
you know, an influence that's there, but it's, but it's subtle.
link |
You don't even think you take note of, and they can find measurable effects that differentiate
link |
the two groups to a high degree of statistical significance and how they respond to certain
link |
challenges or certain kinds of questions that shows a direct influence of the reminder of
link |
their own mortality.
link |
And I've read a number of these studies and they are really convincing.
link |
And so, yeah, I would say that the reason why so many people would say that, yeah, fear
link |
of mortality, it's not front and center in my worldview.
link |
Yeah, I don't really think about it much, doesn't really matter too much.
link |
The reason why they're able to say that is because this thing called culture has emerged
link |
over the course of the last 10,000 years.
link |
And part of the role of culture is to give us a means of not thinking about our mortality
link |
all the time, of not living in terror of the inevitable end, which faces us all.
link |
So it's completely understandable that that's the response because that's what culture
link |
is at least in part four.
link |
It's at least possible that the fear of death, the terror of your mortality is the creative
link |
force that created all of the things around us at this human civilization.
link |
And I think about from an engineering perspective, this is where I lose all of my robotics colleagues,
link |
is I feel like if you want to create intelligence, you have to also engineer in some kind of
link |
echoes of this kind of fear of, you know, fear is such a complicated word, but it's
link |
kind of like a scarcity, a scarcity of time, a scarcity of resources that creates a kind
link |
of anxiety, like deadlines get you to do stuff.
link |
And there's something almost fundamental to that in terms of human experience.
link |
Yeah, well, that's an interesting thought.
link |
So you're basically in order to create a kind of structure that mirrors what we call consciousness.
link |
You better have that structure confront the same kinds of issues and terrors that we do.
link |
Consciousness and suffering only make sense in the context of death.
link |
If you want to, I feel like, if you want to fit into human society, if you're a robot
link |
and you want to fit into human society, you better have the same kind of existential dread,
link |
the same kind of fear of mortality, otherwise you're not going to fit in.
link |
It might be wild, but it's at least like we're talking about all the theories that are at
link |
least worth consideration.
link |
I think that's a really powerful one and definitely one has resonated with me and definitely
link |
seems to capture something beautifully real about the human condition.
link |
And I wonder, of course, it sucks to think that we need death to appreciate life.
link |
But that just may be the way it is.
link |
Well, it's interesting if this robotic or artificially intelligent system understands
link |
the world and understands the second law of thermodynamics and entropy, even an artificial
link |
intelligence will realize that even if its parts are really robust, ultimately it will
link |
I mean, so the time scales may be different, but in a way when you think about it, it doesn't
link |
Once you know that you are mortal in the sense that you are not eternal, the time scale hardly
link |
matters because it's either the whole thing or not because on the scales of eternity,
link |
any finite duration, however large is effectively zero on the scales of eternity.
link |
And so maybe it won't be so hard for an artificial system to feel that sense of mortality because
link |
it will recognize the underlying physical laws and recognize its own finitude.
link |
And then it'll be us and robots drinking beers, looking up at the stars and just having a
link |
good laugh in awe of the whole thing.
link |
I think that's a pretty good way to end it, talking about the fear of death.
link |
We started talking about the meaning of life and ended on the fear of death.
link |
Brian, this was an incredible conversation.
link |
I really, really enjoyed it.
link |
Thanks for the time coming, I'm a huge fan of your work, a huge fan of your writing.
link |
Thanks for talking to me, Brian.
link |
Thanks for listening to this conversation with Brian Green.
link |
To support this podcast, please check out our sponsors in the description.
link |
And now, let me leave you with some words from Bill Bryson.
link |
Physics is really nothing more than a search for ultimate simplicity.
link |
But so far, all we have is a kind of elegant messiness.
link |
Thank you for listening and hope to see you next time.