Speaker 1: What is life? How do you define what things are
Speaker 1: living and what things are dead. You might look at
Speaker 1: a running cheetah and say that thing is clearly living,
Speaker 1: and you look at a chunk of granite rock and
Speaker 1: you say, okay, that thing is not living. But where
Speaker 1: do we draw the line? And when we land on
Speaker 1: other planets someday, what can we realistically expect aliens are
Speaker 1: going to look like? Will we even recognize strange forms
Speaker 1: of life or will we only have the capacity to
Speaker 1: recognize things that are very close to earthly life? And
Speaker 1: what does any of this have to do with Frankenstein
Speaker 1: or ancient Greek philosophers or the possibility of finding a
Speaker 1: cell phone on Mars.
Speaker 2: Welcome to Intercosmos with me David Eagleman.
Speaker 1: I'm a neuroscientist in a all third at Stanford, and
Speaker 1: in these episodes we dive deeply into our three pound
Speaker 1: universe to uncover some of the most surprising aspects of
Speaker 1: our lives. In today's episode, we're not only going to
Speaker 1: dive into our three pound universe, but into the larger
Speaker 1: universe that surrounds us to think about the question of
Speaker 1: what is life? So what do we mean when we
Speaker 1: say something is alive. This is one of the oldest
Speaker 1: questions that biologists have been asking, and it's a strangely
Speaker 1: tough one. So today we're going to take a run
Speaker 1: at this question from a completely different angle, from the
Speaker 1: point of view of theoretical physics. Joining me today will
Speaker 1: be physicist Sarah Walker, who with her colleagues is working
Speaker 1: to ask the question of what is life through a
Speaker 1: very different lens, And we're going to get into questions
Speaker 1: like what we might expect when we discover life elsewhere
Speaker 1: in the universe, and how we can prepare ourselves to
Speaker 1: even know what to look for. But first I want
Speaker 1: to say that this question about what is life is
Speaker 1: one that humans have been asking for about as long
Speaker 1: as we can tell. So in the fourth century BCE,
Speaker 1: you had Greek philosophers like Plato and Aristotle writing about this.
Speaker 1: For example, Aristotle wrote a book called de Anima, or
Speaker 1: on the Soul, and he says, look to be a
Speaker 1: living thing, you possess a soul. And Plato, his mentor,
Speaker 1: was on the same train, talking about a world soul
Speaker 1: that differentiates between living beings and inanimate matter. But you
Speaker 1: had people being more specific too. For example, several decades
Speaker 1: before Plato and Aristotle, the Greek philosopher Empedocles proposed a
Speaker 1: theory of life based on the interaction of four elemental
Speaker 1: forces earth, air, water, and fire. He suggested that life
Speaker 1: is created through just the right combinations of these elements,
Speaker 1: and this is one of the earliest attempts to understand
Speaker 1: life as a combination of natural forces, offering a way
Speaker 1: of distinguishing between living things and inert matter. And another
Speaker 1: Greek Hippocrates, he started to lay the early foundations for
Speaker 1: the biological study of life by focusing on the human body.
Speaker 1: And what he said is there's a balance of four
Speaker 1: humors that are critical to life. You've got blood and
Speaker 1: phlem and yellow bile and black bile.
Speaker 2: So this was not correct, but.
Speaker 1: It started giving the earliest shape to this biological idea
Speaker 1: that life depends on balancing a certain physical state, and
Speaker 1: that's he suggested what separates the living body from non
Speaker 1: living matter. And people started to get more specific about things,
Speaker 1: a little closer to the way that we think about
Speaker 1: them now. For example, Epicurus suggested that all things, including
Speaker 1: living beings, are composed of atoms moving through the void.
Speaker 1: So for the epicureans life is the result of particular
Speaker 1: combinations of atoms, and death is just the dissolution of
Speaker 1: these atomic arrangements. So the difference between living and non
Speaker 1: living matter lies in the specific arrangement of the atoms.
Speaker 1: And then Lucretius in Rome some centuries later wrote a
Speaker 1: poem called on the Nature of Things, and he built
Speaker 1: on this idea, and he said, living beings are distinguished
Speaker 1: from non living things by their particular atomic configurations and
Speaker 1: the ability to move and reproduce. And by the way,
Speaker 1: even though I know Western thinkers the best, this question
Speaker 1: of what his life was being wrestled with around the world.
Speaker 1: So I know that in China in the fourth century BCE,
Speaker 1: the Taoist text called wang Xi reflected on the nature
Speaker 1: of life and existence. It looked at how life emerged
Speaker 1: from the interplay of natural forces, like what they called chi,
Speaker 1: which was their notion of life energy. And in first
Speaker 1: century India you have Iravedic texts discussing life in terms
Speaker 1: of the balance among three doshas, Vada, Pitta, and Kafa.
Speaker 1: This is all stuff that's not so relevant except for
Speaker 1: ritual purposes. But the idea that was being pursued was
Speaker 1: that somehow life is sustained by the equilibrium of different forces. Okay,
Speaker 1: so the point I want to make here is that
Speaker 1: the question of what is life is not a new question.
Speaker 1: And there's a sense in which all these thinkers and
Speaker 1: books they foreshadow later biological thought by asking this question
Speaker 1: what animates matter? What makes it alive? And we see
Speaker 1: the same question reflected all over literature. The most obvious
Speaker 1: example is Mary Shelley is Frankenstein, and you may know
Speaker 1: that tells the story of Victor Frankenstein, who's a scientist
Speaker 1: who sets out to create life by reanimating dead tissue.
Speaker 1: And the creature he brings to life is assembled from corpses,
Speaker 1: but becomes a sentient, feeling being, And so readers are
Speaker 1: challenged and thinking about the boundaries between living and non
Speaker 1: living matter. And this sort of mythology reaches back hundreds
Speaker 1: of years earlier. For example, Jewish folklore has the story
Speaker 1: of the Golum, which is a creature who is shaped
Speaker 1: out of clay, and when someone writes something on his head,
Speaker 1: he comes to life as a protector, and if you
Speaker 1: remove a letter from the word, he becomes inanimate again.
Speaker 1: And the myth of the Golam inspired ideas from Frankenstein
Speaker 1: to movies that deal with artificial beings like ex Machina,
Speaker 1: where you've got a robot that gets artificially intell gin
Speaker 1: and becomes something that we might call alive. So this question,
Speaker 1: what is the boundary between life and death? This is
Speaker 1: a question that has long been on the forefront of
Speaker 1: the human mind. But of course there's a deeper question also,
Speaker 1: not just about human life, but about all the life
Speaker 1: forms we find on this planet. Because when we look
Speaker 1: around the animal kingdom, we find all kinds of very
Speaker 1: strange life forms, like platypuses or jellyfish or sephonophores. Anyway,
Speaker 1: we look at these things and we think, wow, those
Speaker 1: are really strange. And then we look to plants and
Speaker 1: we say, well, they seem like to qualify as life also.
Speaker 1: And then we look at single celled bacteria, which we
Speaker 1: didn't even know existed until very recently in history, when
Speaker 1: lewand Hook made a microscope and found these little creatures
Speaker 1: which you called animacules, which we now call uni cellular organisms. Anyway,
Speaker 1: we look at those, we say, you know, that seems
Speaker 1: like life too, But what do these all have in common?
Speaker 2: Well, of course, the weird part of the story is.
Speaker 1: That when you look at what we are made out of,
Speaker 1: and what jellyfish and house plants and bacteria are made
Speaker 1: out of, it's the exact same stuff. It's the exact
Speaker 1: same stuff that makes our molecules, that makes their molecules,
Speaker 1: and by the way, the same stuff that makes rocks
Speaker 1: and oceans and so on. You got carbon and nitrogen
Speaker 1: and oxygen and calcium and the rest of the atoms.
Speaker 1: But it's all non living stuff that makes us. Somehow,
Speaker 1: life is built out of a bunch of non life.
Speaker 1: Now you may know that. In nineteen fifty two, a
Speaker 1: scientist named Stanley Miller showed that if you put a
Speaker 1: bunch of inorganic compounds together, like you put methane and
Speaker 1: ammonia and hydrogen and water, and then you zap that
Speaker 1: with electricity, you get amino ad acids, which are the
Speaker 1: building blocks of proteins. And this was such a striking
Speaker 1: result because it showed the way that molecules we see.
Speaker 2: In living things, like the amino.
Speaker 1: Acids, could emerge from dead stuff if you just have
Speaker 1: the right kind of atmosphere. And I wasn't alive in
Speaker 1: the nineteen fifties. But I imagine the mood was really
Speaker 1: optimistic that from there it would be a straightforward run
Speaker 1: to see how all the pieces and parts would come
Speaker 1: together to build life. But here we are over seventy
Speaker 1: years later, and we still don't know how the story
Speaker 1: comes together. But the problem is actually worse than that,
Speaker 1: because almost everything that we as biologists ask about life
Speaker 1: has to do with life on Earth, where everything is
Speaker 1: built on atoms like carbon and on big molecules like
Speaker 1: DNA and RNA, which carry the information to build creatures.
Speaker 2: Small and large.
Speaker 1: But there's no necessity that life elsewhere in the cosmos
Speaker 1: will be built of the same stuff and in the
Speaker 1: same way. And here's the way to think about this.
Speaker 1: In high school biology, we all learned that we call
Speaker 1: something alive if it's organized into cells or even a
Speaker 1: single cell, and it has to have metabolism, meaning it
Speaker 1: converts energy into stuff that it can use, and it
Speaker 1: can regulate its internal environment and grow and develop and
Speaker 1: reproduce and respond to things. And it has to have
Speaker 1: some sort of programming code like genetic material that says
Speaker 1: how to build new ones and so on. But no
Speaker 1: matter how carefully people try to define this they always
Speaker 1: get into gray areas like viruses which can reproduce but
Speaker 1: only inside the cells of a host, and they don't
Speaker 1: have metabolism or respond to stimuli on their own. So
Speaker 1: do you call them living or non living?
Speaker 3: Well?
Speaker 2: Who knows.
Speaker 1: And currently we're seeing all kinds of advances in biotech
Speaker 1: which are creating synthetic life forms, which raises all kinds
Speaker 1: of strange questions about what criteria should define life. But
Speaker 1: I think the problem isn't even about blurry boundaries between
Speaker 1: living and non living. The problem is that the criteria
Speaker 1: we use in biology textbooks, it's not really thinking big
Speaker 1: enough when we consider life in other forms elsewhere in
Speaker 1: the cosmos. And you may know that there's a lot
Speaker 1: of effort going into finding signatures of other life forms
Speaker 1: and the cosmos. And generally when people imagine meeting some
Speaker 1: alien civilization, they generally think, oh, it probably looks.
Speaker 2: Sort of like us.
Speaker 1: You got two eyes, even if those eyes are bigger,
Speaker 1: and it's got a head, even if the head's a
Speaker 1: little bigger, and maybe it's got pointy ears. And we
Speaker 1: say take me to your leader, and they say, okay,
Speaker 1: follow me. But this all may lead us to have
Speaker 1: a very difficult time recognizing other kinds of life in
Speaker 1: the cosmos if what we're looking for is a Hollywood
Speaker 1: actor with some green makeup. So what if we really
Speaker 1: expanded our thinking on this, What if we really thought
Speaker 1: about other ways that we could define or at least
Speaker 1: detect life. So I wanted to see how other people
Speaker 1: might be thinking about this question, And for that I
Speaker 1: wanted to look beyond earth biologists. When you're looking for
Speaker 1: someone who has a very big view of things, you
Speaker 1: generally look to physicists. Now, physicists have not always been
Speaker 1: interested in the question of life, although one of the
Speaker 1: most famous little books entitled What Is Life was a
Speaker 1: nineteen forty three series of lectures by Irwin Schrodinger, the
Speaker 1: quantum physicist.
Speaker 2: But generally the question of.
Speaker 1: Life seems like the wrong sort of level of question
Speaker 1: for a lot of physicists. And that's why I was
Speaker 1: so pleased to come across the book of Sarah Walker,
Speaker 1: who's a theoretical physicist.
Speaker 2: At Arizona State University.
Speaker 1: She wrote a book called Life as No One Knows It,
Speaker 1: and she looks at the question of how she could
Speaker 1: measure life so that we would know when we find it.
Speaker 1: So I called her up to hear her take on this,
Speaker 1: and here is Sarah Walker. Okay, So, Sarah, I want
Speaker 1: to get into this issue about how physicists think about
Speaker 1: things differently than biologists do. And you give this lovely
Speaker 1: analogy in your book about how a physicist thinks about
Speaker 1: let's say gravity, So.
Speaker 2: Tell us about that.
Speaker 1: Yeah.
Speaker 3: I like using gravity as a good example because it's
Speaker 3: pretty familiar to us, and we kind of accept gravity
Speaker 3: as a real objective feature of reality, and forget that
Speaker 3: people had to actually invent our concepts of gravity. The
Speaker 3: whole process of doing that was really trying to understand
Speaker 3: regularities that unify behavior across a huge diversity of objects.
Speaker 3: And so the kind of things that were of interest
Speaker 3: to early physicists were balls, rolling down, inclined planes, and
Speaker 3: planetary motion in the heavens.
Speaker 4: And you know what they.
Speaker 3: Realized was if they chose a sufficiently abstract representation, they
Speaker 3: could talk about those things in the same language. And
Speaker 3: prior to that, in human history, we had no idea
Speaker 3: that planetary motion was governed by the same principles that
Speaker 3: keep us on this planet. Right, So it was a
Speaker 3: huge conceptual leap made by our species, and it was
Speaker 3: really one about trying to find the right kind of
Speaker 3: representation that could describe a huge diversity of forms. And
Speaker 3: this is why it gets interesting when we're talking about biology,
Speaker 3: because in biology we have a plethora of diverse kinds
Speaker 3: of forms of life on this planet. And a critical
Speaker 3: question if you want to talk about whether there are
Speaker 3: governing laws or principles of life, is is there some
Speaker 3: simple unifying description that could unify all of that diversity
Speaker 3: of life on Earth and not just explain what we
Speaker 3: see her on this planet, but also on other planets,
Speaker 3: which is one of the key questions I'm interested in.
Speaker 1: So we're going to get into that question of what
Speaker 1: is life? How would a physicists think about life? But
Speaker 1: how did you get interested in that question?
Speaker 3: I wanted to be a cosmologist or a particle physicist.
Speaker 4: When I was an undergrad.
Speaker 3: I fell in love with theoretical physics and its ability
Speaker 3: to describe nature abstractly and the fact that the human
Speaker 3: mind could come up with descriptions of nature we could
Speaker 3: go test, so things like gravitational waves that we had
Speaker 3: no knowledge about, we could go out and look for
Speaker 3: just because the theory predicted them, and then learn new
Speaker 3: things about reality or neutrinos or another example. Right, these
Speaker 3: are not things that are like, you know, privy to
Speaker 3: our daily perception.
Speaker 4: Right.
Speaker 3: We didn't evolve capacity to sense these things. Yet we
Speaker 3: can build theories that allow us to build technology to
Speaker 3: sense them. And so I was deeply intrigued by that
Speaker 3: whole process and that whole sort of conception of nature
Speaker 3: that you know, underlies what physicists do, you know, at
Speaker 3: this sort of edge of developing new descriptions of reality.
Speaker 3: And it was the case that through my undergrad education
Speaker 3: I just really decided I want to be a theoretical physicist.
Speaker 3: When I got to graduate school, I was like dead
Speaker 3: set on it. And my PhD advisor, Marcelo Gleister, a
Speaker 3: really fantastic thinker, was just you know, later in his
Speaker 3: career as a cosmologist and thought, you know, wanted to
Speaker 3: be great if I did some projects I'm origins life.
Speaker 3: And so I was pretty resistant at first because because
Speaker 3: of you know, kind of what you were indicating initially,
Speaker 3: Like physics and biology are usually traditionally seen as totally separate,
Speaker 3: and in some sense physicists look down on biology as
Speaker 3: a lesser problem than the kind of grand sweeping things
Speaker 3: that physicists study. So it just wasn't on my radar
Speaker 3: from my education that there would really be fundamental problems
Speaker 3: of the kind I was interested in. And I always
Speaker 3: loved biological sciences, but like, I really loved this idea
Speaker 3: of deep, abstract, unifying principles and really understanding at a core,
Speaker 3: you know, the nature of physical reality. And so what
Speaker 3: really sold me on the original life and why I
Speaker 3: decided to dedicate my career to it is I realized
Speaker 3: it was like a major open question, and major in
Speaker 3: the sense it wasn't just that we didn't, you know,
Speaker 3: have the right tools to answer the question.
Speaker 4: We didn't even know what questions to ask.
Speaker 3: And these places where we have these sort of conceptually
Speaker 3: open you know, like like nobody knows how to think
Speaker 3: about it, Like those are the spaces that I love
Speaker 3: to be in because those are the ones where you
Speaker 3: really have this opportunity to do something new and also
Speaker 3: like to maybe discover something kind of deep that we
Speaker 3: didn't know before.
Speaker 1: So the way that a biologist thinks about what is
Speaker 1: life is we look and we see all these cells,
Speaker 1: we see cell processeds, and we discovered DNA and things
Speaker 1: like that and we think, Okay, we're going to make
Speaker 1: a theory about life, but how do you, as a
Speaker 1: theoretical physicist start tackling the problem?
Speaker 4: It was interesting.
Speaker 3: So my first, like, I really, what I'm interested in
Speaker 3: is how does non living matter transition to living matter?
Speaker 3: And in order to answer that question, you need to
Speaker 3: have some sense of what you mean when you say
Speaker 3: something is life or something is alive, or something as
Speaker 3: living matter. And so I've always been very questioned driven.
Speaker 3: I think a lot of people that ask the what
Speaker 3: is life question, that's their question. But the way I
Speaker 3: approach it is that question is in service of solving
Speaker 3: this other very big open question in science, which is
Speaker 3: where does life come from in the first place? And
Speaker 3: so I was actually early in my career I was
Speaker 3: steered away even by some biologists from working on the
Speaker 3: original life because they thought I could learn more about
Speaker 3: biology by studying biological forms as we already understand them.
Speaker 3: And I intrinsically felt that there was something really new
Speaker 3: and different to learn about the original life transition itself.
Speaker 3: And so the sort of traditional approach, as I said,
Speaker 3: has been to ask what is life and then try
Speaker 3: to answer that question directly, And I just don't think
Speaker 3: that that's actually useful exercise in these sort of more
Speaker 3: fundamental aspects or getting at the frontiers of detecting life
Speaker 3: elsewhere or origins of life, because what we end up
Speaker 3: doing is kind of having these descriptors life life is,
Speaker 3: you know, requires metabolism to sustain itself, Life needs genetics
Speaker 3: or these things that are very anthropercentric and base dating
Speaker 3: examples as we know it and might you know, and
Speaker 3: those examples don't apply to like the earliest life on
Speaker 3: Earth as far as we know, because we don't know
Speaker 3: if it had a genetic system or not, for example.
Speaker 3: So we need deeper descriptions to go further than the
Speaker 3: biology we know. And that's what I got interested in,
Speaker 3: and that needs to be driven by really having a
Speaker 3: compelling question that you're trying to answer to focus your effort.
Speaker 4: How you build theory.
Speaker 1: Okay, so you asked the question of how does non
Speaker 1: living stuff become living stuff? And how did you how
Speaker 1: did you go about it?
Speaker 2: How did you start making progress on a question like that?
Speaker 3: Yeah, so obviously I didn't know a lot about biology
Speaker 3: and chemistry when I started. You can pick up a
Speaker 3: lot reading and talking to people, but it wasn't it's
Speaker 3: not my training, it's not my field of expertise. I
Speaker 3: would I will always stay upfront. I have all of
Speaker 3: the cognitive biases of somebody that was trained in physics.
Speaker 4: I really tried to fight them.
Speaker 3: But you know, I'm very aware of my disciplinary training,
Speaker 3: and part of the reason I'm so aware of it
Speaker 3: is walking into origins of life as a PhD student.
Speaker 3: Almost everybody there comes from a different discipline, right, Like
Speaker 3: there's the organic chemists and they have a camp of
Speaker 3: how they think about it. There's the genetics and molecular
Speaker 3: biologists and they have a camp about how they think
Speaker 3: about the problem. And there's the physicists and they have
Speaker 3: a camp of how they think about the problem. And
Speaker 3: so each discipline or your perspective kind of had a
Speaker 3: hypothesis that was informed by their discipline but not the others.
Speaker 3: And so I really tried to abandon all of that
Speaker 3: and just really try to focus on what the fundamental
Speaker 3: nature of the problem was. But obviously, starting from physics,
Speaker 3: I wanted to start with, like, why can physics not
Speaker 3: explain the origin of life? And that led to focus
Speaker 3: focus on information and causation because it seems to be
Speaker 3: the case that in living systems information is causal. So
Speaker 3: for example, you know there's people listening to this right now,
Speaker 3: I could say raise your hand.
Speaker 4: Some of you may raise your hands.
Speaker 3: I'm raising my hand right, And so we're separated in
Speaker 3: space and time, and there's causation there, right, and it's
Speaker 3: carried by words which are you know, very abstract, but
Speaker 3: there must be some kind of physicality to them if
Speaker 3: they have some causation in the world with sort of
Speaker 3: my thinking. And obviously there's also like in genomes we
Speaker 3: talk about them carrying information, etcetera. So this language of
Speaker 3: information is all over biology. And so the first problem
Speaker 3: I identified, which I wrote this paper with my postdoc
Speaker 3: advisor Paul Davies in twenty thirteen called the Algorithmic Origins
Speaker 3: of Life, was the original life transition must have something
Speaker 3: to do with a transition in causation and information.
Speaker 4: And physical systems.
Speaker 3: And I've used that kind of as the paradigm of
Speaker 3: most of my career. Actually all of my work is
Speaker 3: training answer a question I posed in that paper. And
Speaker 3: so now I've settled on this new approach that I'm
Speaker 3: very excited about because of the connection between deep connection
Speaker 3: between theory and experiment called assembly theory, which is an
Speaker 3: attempt to understand how information really is the sort of
Speaker 3: underlying mechanism for the existence of some objects, but doing
Speaker 3: it in a much more physical way.
Speaker 2: Cool.
Speaker 1: So, just before we get into assembly theory, so give
Speaker 1: us an exams example of information and causation. Give us
Speaker 1: an example. How do you think about that in terms
Speaker 1: of life.
Speaker 3: Yeah, an example might be something like a technological artifact
Speaker 3: like a cell phone. We don't expect them to spontaneously
Speaker 3: emerge from the geochemistry of Mars. So if we found
Speaker 3: a cell phone on Mars, for example, we would consider
Speaker 3: it a biosignature because it has so much history necessary
Speaker 3: to construct something like a cell phone. Right, So, cell phones,
Speaker 3: if they appear in the universe at all, you know,
Speaker 3: should be expected to emerge on planets that have evolution
Speaker 3: of life over billions of years and evidential evolution of
Speaker 3: intelligent beings that construct cell phones.
Speaker 4: They don't happen for free, all right.
Speaker 3: That's a key conjecture of the theory that I'm working on,
Speaker 3: is that those kinds of objects require information.
Speaker 1: Tell us where this is landed with assembly theory, and
Speaker 1: how do you think about life.
Speaker 3: Yeah, So the sort of key conjecture of assembly theory
Speaker 3: is that there are some objects that are just too
Speaker 3: complex to form spontaneously ever in the history of the universe.
Speaker 3: So this is this is very sort of counter to
Speaker 3: the sort of standard paradigm in physics right now, which
Speaker 3: is the idea that any object of our arbitrary complexity
Speaker 3: can fluctuate into existence with very low probability. That's completely
Speaker 3: consistent with all of our current theories of physics. And
Speaker 3: yet we don't see you know, brains popping into existence spontaneously, right,
Speaker 3: they evolve in bodies, and so there's this famous argument
Speaker 3: about Boltzmann brains, you know, being spontaneous objects, and it
Speaker 3: raises all kinds of paradoxes in physics. So both my
Speaker 3: brains are this idea that due to spontaneous fluctuation in
Speaker 3: the laws of physics it could be thermodynamics or quantum fluctuations.
Speaker 3: You can spontaneously fluctuate particles to existence, for example, and
Speaker 3: quantum physics as long as they're a particle antiparticle, and
Speaker 3: they'll just you know, spontaneously fluctuate out of existence. So
Speaker 3: these kind of effects can happen. And if you run
Speaker 3: that and just say, you know, like as a logical experiment,
Speaker 3: you say, well, there's no sort of bound on what
Speaker 3: could fluctuate into existence. You lead to a sort of
Speaker 3: paradoxical situation where something like a brain could also spontaneously
Speaker 3: fluctuate into existence. And this is paradoxical because if you
Speaker 3: were such a brain, it's not clear that your experiences
Speaker 3: would be anything different than the experiences that we have.
Speaker 3: So for example, you know, you could have just fluctuated
Speaker 3: into existence right now hearing me influctuated out of existence,
Speaker 3: and then you wouldn't know if this moment is actually
Speaker 3: the one that you fluctuated into existence, and now it's
Speaker 3: you know, so it's like it's very it's and it's
Speaker 3: a problematic because if these things are a possibility, affects
Speaker 3: some of our cosmological models and some of the other
Speaker 3: areas of physics. And it's also related to other problems
Speaker 3: in physics, like fine tuning of the initial condition, which
Speaker 3: is another issue where physics directly confronts biology, because to
Speaker 3: describe complexity, it has to be in the initial state
Speaker 3: of the universe that there was you know, a precise
Speaker 3: amount of information necessary to construct things like us, and
Speaker 3: an assembly theory, we think that all of the information
Speaker 3: is actually constructed over time in the dynamics of the
Speaker 3: universe unfolding and in particular on planets to build things
Speaker 3: that are complex like us. And that's the phenomena that
Speaker 3: we call life. And so the sort of key testable
Speaker 3: conjecture that we have so far is that there's actually
Speaker 3: a complexity threshold in chemistry where and we actually talk
Speaker 3: about it in terms of an assembly index, which is
Speaker 3: sort of a minimal number of steps for constructing an object.
Speaker 3: So if you want to think about legos, you're sticking
Speaker 3: them together, and you can take parts you've already built
Speaker 3: and build up to a particular structure, you'd have sort
Speaker 3: of a minimal number.
Speaker 4: Steps to make that structure.
Speaker 3: And you can imagine if you're shaking a lego table
Speaker 3: right and you're doing random kind of configurations of objects,
Speaker 3: you'll get like a couple pieces sticking together, and they
Speaker 3: might repeat those structures, but you're not going to expect
Speaker 3: to see lego hogwarts of the taj Mahal, you know,
Speaker 3: spontaneously assemble even in you know the amount of time
Speaker 3: the universe has has had to you know, potentially, like
Speaker 3: you know, thirteen point seven billion years of shaking is
Speaker 3: not going to get you there. So you can imagine,
Speaker 3: like where is the boundary between the things that are
Speaker 3: really likely those small couple of things stuck together that
Speaker 3: we should find ubiquitous in the universe and something like
Speaker 3: the taj Mahal, which you know requires a lot of
Speaker 3: cultural information, a lot of evolutionary you know, like well,
Speaker 3: billions of years of biological evolution to get intelligent beings
Speaker 3: and then thousands of years of cultural evolution to build
Speaker 3: something that complicated.
Speaker 4: Right, So, so.
Speaker 3: What we say in assembly theory is that there's actually
Speaker 3: a threshold and if we find structures above this threshold,
Speaker 3: where we find abundant highly assembled objects, then that's a
Speaker 3: signature of life. And this has all kinds of really
Speaker 3: interesting consequences because now you've made this history of construction
Speaker 3: in this way of building the object kind of a
Speaker 3: physical property that and we can go measure it in
Speaker 3: the lab for molecules, and we've done that, We've done
Speaker 3: tests on biological non biological samples, and it seems that
Speaker 3: there really is a threshold value in this sort of
Speaker 3: complexity assembly index above which things are only produced by life.
Speaker 2: So let me unpack that just a little bit.
Speaker 1: So when you talk about things being testable, so you
Speaker 1: test them with chemistry essentially, and you're asking how complex
Speaker 1: a molecule do I expect to get accidentally just from
Speaker 1: things bumping into one another, Versus what's some threshold over
Speaker 1: which I say, wow, you know what, that thing that
Speaker 1: molecule is too complex that that's not going to come
Speaker 1: about by accident.
Speaker 3: That yeah, that's exactly what we're trying to test for.
Speaker 3: And the way that you actually do it is with
Speaker 3: sort of standard instrumentation in a chemistry lab, so we
Speaker 3: can measure this feature of this minimal number of stepsi
Speaker 3: assembly index using mass spectrometry NMR and for reds, so
Speaker 3: it's possible to take samples and actually test this conjecture,
Speaker 3: and so far it's held up.
Speaker 1: And the conjecture that holds up is that there's some
Speaker 1: threshold of complexity and you get things accidentally for a while,
Speaker 1: but it doesn't get more complex than that.
Speaker 2: It doesn't build the cell phone.
Speaker 3: So the expectation is that planets that don't have life
Speaker 3: will only be able to build molecular objects or you know,
Speaker 3: any objects like you know, it won't be able to
Speaker 3: build a cell phone, for example, but that boundary of
Speaker 3: what it can you know, what it can produce, is
Speaker 3: tightly bounded. There's like an upper limit in the complexity
Speaker 3: of the molecules, and life is the only thing that
Speaker 3: can cross that. And so I think about it oftentimes
Speaker 3: in terms of like if you imagine that you can
Speaker 3: think about the space of all possible objects that the
Speaker 3: universe could generate, and they're stacked by how hard they
Speaker 3: are to build, by their sort of construction history, and
Speaker 3: what objects need to precede them in order for them
Speaker 3: to exist that physical Like, what assembly theory is doing
Speaker 3: is making that a physical space by tying that the
Speaker 3: structure of that space to something we can measure in
Speaker 3: the lab. And then we're saying that life is the
Speaker 3: only thing that you find beyond a certain boundary in
Speaker 3: that space.
Speaker 1: So how does that help you understand how non living
Speaker 1: things become living?
Speaker 3: Well, what it does is it allows us first to
Speaker 3: measure whether this has happened, which means we can actually
Speaker 3: start a new experimental paradigm for the original life. So
Speaker 3: traditionally in my field, you know, the standard set of
Speaker 3: experiments that people have done is to try to look for,
Speaker 3: you know, a chemical system that could produce an amino
Speaker 3: acid because we use amino acids in our bodies and
Speaker 3: all biological life forms do, or things that could make
Speaker 3: components of DNA or RNA again, because we find that
Speaker 3: in you know, all life on Earth, and so those
Speaker 3: have been really targeted syntheses, and I think that that's
Speaker 3: a bit of a challenge because it's looking specifically for
Speaker 3: molecular structures that we find in life on Earth, so
Speaker 3: it's not general, as we talked about at the beginning.
Speaker 3: But also it's problematic because we're putting so much agency
Speaker 3: and selection in because we know the goal in mind
Speaker 3: of what we want to produce, that we're actually sort
Speaker 3: of biasing the space to already produce things, even if
Speaker 3: they're complex, by putting boundary conditions in the experiment. And
Speaker 3: so the sort of vision that I build in the
Speaker 3: book about these original life experiments really comes from my
Speaker 3: colleague Lee Cronin, who originally developed assembly theory and also
Speaker 3: has this very large experimental lab trying to develop new
Speaker 3: platforms for original life experiments. Is to try to do
Speaker 3: these sort of random soup chemistries where you actually just
Speaker 3: try to model, you know, geochemistry, and you don't constrain it,
Speaker 3: and you try to detect if you start getting complex
Speaker 3: things out and at what level you start getting.
Speaker 4: Complex things out.
Speaker 3: And so if this idea of this threshold is accurate,
Speaker 3: we should be able to detect when life spontaneously emerges
Speaker 3: through a random chemical search. And so we kind of
Speaker 3: think of like it almost is like a chemical search engine,
Speaker 3: Like we don't know how often alien life or any
Speaker 3: kind of life forms form in this huge space of chemistry,
Speaker 3: and so we want to build a machine that allows
Speaker 3: us to actually explore that space and look for living things.
Speaker 3: But we need to actual measure we can go and
Speaker 3: do in the chemistry.
Speaker 4: To look for it.
Speaker 3: So this is a very big paradigm shift in the
Speaker 3: way we're thinking experimentally about origins of life.
Speaker 2: So let me summarize this.
Speaker 1: Where we are so far, so you're you and Lee
Speaker 1: are looking at this issue of okay, lots of chemicals together.
Speaker 1: You expect things to be under the threshold of what
Speaker 1: you would call, you know, a certain complexity threshold. But
Speaker 1: you're asking how many times does something pop above that threshold?
Speaker 1: Like when do we see something go above that? And
Speaker 1: when it does go about that, we'd say, okay, there's
Speaker 1: something that we'd call life about that.
Speaker 3: Yes, And one of the other key things that I'm
Speaker 3: working on is developing sort of a theory of the
Speaker 3: actual transition between those phases. So we have a lot
Speaker 3: of the sort of scaffold those theory worked out in
Speaker 3: terms of how we think about selection in assembly spaces,
Speaker 3: which is kind of the space of these kind of
Speaker 3: operations of building up objects, but which is a very
Speaker 3: abstract space, just like you know, we always talk about
Speaker 3: in physics these very abstract spaces. So I kind of
Speaker 3: think of it like we have, like you know, coordinate
Speaker 3: geometry for like gravity, we have this sort of space
Speaker 3: of possibilities and the sort of relationships between objects is
Speaker 3: an assembly space. It's kind of the space that this
Speaker 3: physics lives in. But the sort of idea there is
Speaker 3: exactly what you're saying that we want to be able
Speaker 3: to go and detect this transition. So we also need
Speaker 3: to be able to predict from the theory when it
Speaker 3: should happen, and so that's something that we're working on
Speaker 3: quite extensively right now.
Speaker 2: Cool. So we're still in very early days with this,
Speaker 2: but when you imagine, Yeah, when you imagine what a
Speaker 2: search for life on other planets would look like, what
Speaker 2: strikes you.
Speaker 3: Yeah, So some of the things I really love about
Speaker 3: the development of new theories is also like the philosophy
Speaker 3: that comes along with it. So I imagine that, you know,
Speaker 3: we'll go look for high assembly index structures in abundance
Speaker 3: on other planets, right, So we'll take, you know, in
Speaker 3: the Solar System, we might go to Titan or Enceladus
Speaker 3: and you know, bring a mass spectrometer and try to
Speaker 3: detect molecules with many parts, you know, that have these
Speaker 3: kind of properties that I was talking about. And so
Speaker 3: that's a doable experiment, Like we're almost pretty much ready
Speaker 3: to fly those kind of experiments right now. But from
Speaker 3: the philosophical side of it, it's interesting to me to
Speaker 3: think about that what we're looking for when we're looking
Speaker 3: for living things in the universe is we're looking basically
Speaker 3: for causal structures that are very deep in time. So
Speaker 3: all of this causation in history is necessary to maintain
Speaker 3: the existence of these objects. And it's actually because we
Speaker 3: talk about it as a measurable, observable feature of an object.
Speaker 3: You can go in the lab and measure you know
Speaker 3: how deep in this construction history a particular molecule is.
Speaker 3: Now you've made evolutionary time quote unquote in some sense
Speaker 3: of physical attribute of objects, and this kind of really
Speaker 3: radically freeframes I think some of the ways that we
Speaker 3: need to think about the physics of life. So, you know,
Speaker 3: going back to gravitation, you know, one of the reasons
Speaker 3: that new In and Galileo and the generation could come
Speaker 3: up with theories of gravity is because they started being
Speaker 3: able to measure time and seconds with high accuracy, and
Speaker 3: they had a way of measuring mass, and those became
Speaker 3: the variables that informed their theory. And so now we
Speaker 3: have a way of going in the lab and measuring
Speaker 3: you know, assembled structure that's you know, associated with the
Speaker 3: history that goes into an object, the information that goes
Speaker 3: into an object. So now we can talk about that
Speaker 3: as a physical property.
Speaker 2: That's terrific.
Speaker 1: And so when you imagine, hey, we sent the mass
Speaker 1: spectrometer to these moons and we found something that's above
Speaker 1: this threshold of complexity, and we're going to call that life.
Speaker 2: What's interesting?
Speaker 1: Of course, you know, we all have grown up with
Speaker 1: this history of literature that has very earth like creatures,
Speaker 1: you know, maybe with point to your ears or something,
Speaker 1: but otherwise they're about like us.
Speaker 2: What do you think of.
Speaker 1: When you think about the size of the possibility space
Speaker 1: and what what we would even recognize as being something
Speaker 1: interesting to us.
Speaker 4: Yeah, I've always had a challenge.
Speaker 3: So it's interesting being an astrobiologist because a lot of
Speaker 3: people want to ask you the question.
Speaker 4: Like what will aliens look like?
Speaker 3: And I literally, you know, I think the space is
Speaker 3: so huge. I think we cannot anticipate it. And so,
Speaker 3: you know, I talked a little bit about the possibility space,
Speaker 3: but you know, you can actually put numbers on it
Speaker 3: for chemistry. We can't put it for all possible technologies,
Speaker 3: which is one of the reasons that you know, the
Speaker 3: search for techno signatures or signs of technology, which is
Speaker 3: a very big area of astrobiology and increasing enthusiasm for
Speaker 3: you know, like it's hard to imagine what other technologies
Speaker 3: will emerge on other planets, right, we can't even anticipate
Speaker 3: what technologies we're going to happen next year. But if
Speaker 3: you think about chemistry, you can at least kind of iterate.
Speaker 3: You can talk about, you know, how you stick bonds
Speaker 3: together and how many molecules there are. And so my
Speaker 3: favorite example, just to give you a sense of the
Speaker 3: size of the space is to think about the molecule
Speaker 3: taxi al I think it has I don't remember. It's
Speaker 3: more like our formula, but it's not that big. It's
Speaker 3: like something like forty or fifty carbon atoms and it's
Speaker 3: got oxygen and hydrogen. It it's an anti cancer drug.
Speaker 3: If you wanted to make every single molecule with that
Speaker 3: molecular formula, it would fill one point five universes in volume.
Speaker 3: That's one molecule or another sort of big numbers ten
Speaker 3: to the sixty molecules that are like small molecula weight
Speaker 3: like less than five hundred amy, which is about the
Speaker 3: size of two amino acids. So like the universe cannot
Speaker 3: make every possible molecule, keminformaticians that do drug design cannot
Speaker 3: even predict the structure.
Speaker 4: Of every possible molecule.
Speaker 3: So this is like the frontier and pharmaceutical drug design
Speaker 3: is we don't know how to explore the space because
Speaker 3: it's just so big. It's unimaginably big. And so this
Speaker 3: is the issue with alien life. Alien life, you know,
Speaker 3: presumably will start in chemistry on planets, and the space
Speaker 3: of possible chemistries is so large we can't even actually
Speaker 3: computationally explore it on Earth.
Speaker 1: So what you're doing is putting a metric to say, look,
Speaker 1: there is life here on let's say and sell it us.
Speaker 1: But it might be so different from what we've ever
Speaker 1: even thought about.
Speaker 2: There's no meaningful communication with it.
Speaker 4: Yeah, and I think I think you know.
Speaker 3: Step one is do we have a sense that we
Speaker 3: understand enough about what life is to detect it independent
Speaker 3: if we know what kind of substrate it's instantiated in.
Speaker 3: And that was really always the question for me, because
Speaker 3: we don't know what chemistries are possible, we don't know
Speaker 3: what technologies are possible. And this is really the value
Speaker 3: of the sort of abstraction that physicists do is because
Speaker 3: you're looking at something that's such a deep, universal, abstract layer,
Speaker 3: you can start talking about systems that you haven't anticipated
Speaker 3: and still be able to measure them and look for them.
Speaker 4: Right.
Speaker 3: So it's that's why I think this kind of approach
Speaker 3: is so important for these problems, whereas it might not
Speaker 3: be important for a biologist studying life on Earth because
Speaker 3: they don't need to anticipate, you know, this huge possibility
Speaker 3: space for the chemistry of life because we have what
Speaker 3: chemistry on life?
Speaker 4: You know, life selected on Earth.
Speaker 2: Yeah, no, I agree.
Speaker 1: I think it's I think it's amazing to be able
Speaker 1: to quantify this and say, hey, look there's something happening
Speaker 1: here that wouldn't happen by accident.
Speaker 2: Let me ask you this I'm curious about. There's this
Speaker 2: notion of convergent evolution.
Speaker 1: For example, you know, we and octopuses both seem to
Speaker 1: have intelligence, but they have mollusc brains. We have ammalian brains,
Speaker 1: totally different structures, and yet they've converged on this thing.
Speaker 1: Or you know, insects fly and birds fly with totally
Speaker 1: different wings, but evolution has converged on something. When you
Speaker 1: just speculate about finding alien life someday, do you think
Speaker 1: things like intelligence the way we think about it, or
Speaker 1: even consciousness is something that we would you find or
Speaker 1: look for.
Speaker 2: What's your middle of the night speculations on that?
Speaker 3: Uh, you know, with usual with tough topics, I change
Speaker 3: my mind daily, But which is good and healthy? And
Speaker 3: you know, as a scientist, I think we always have
Speaker 3: to be like constantly fact checking ourselves and just making
Speaker 3: sure that we're upfront about it. So, but my current thinking, uh,
Speaker 3: I think life is the process of generating complex structure
Speaker 3: over time. And you know, it's not always like a
Speaker 3: linear trend, right obviously, Like even on Earth, there there's
Speaker 3: periods where you know, like evolution doesn't seem to always
Speaker 3: go in a direction of increasing complexity. But I think
Speaker 3: if you think at a planetary scale of this process
Speaker 3: of it, you know, basically, you know, sort of the
Speaker 3: fundamental principle I have in mind about what life is
Speaker 3: is life is the mechanism of how the universe creates
Speaker 3: what gets to exist.
Speaker 4: Because this possibility space is.
Speaker 3: So large in finite time, finite resource, the universe cannot
Speaker 3: create every possible object. And so what happens is you
Speaker 3: get these orally contingent trajectories constructing more and more complex structures.
Speaker 4: And as they have.
Speaker 3: More and more information, they can make more and more
Speaker 3: complex structure. And so I think that's actually the universal
Speaker 3: feature of life, is this idea of information constructing possibilities
Speaker 3: over time. And it emerges on planets because chemistry is
Speaker 3: the first place that that's necessary even to explore the
Speaker 3: structure of chemistry. So if you take that as fundamental
Speaker 3: and you ask the questions about intelligence and consciousness. My
Speaker 3: take on consciousness is consciousness is something related to the
Speaker 3: depth and time of physical objects.
Speaker 4: So things like us that.
Speaker 3: Are four billion years old have a lot of historical
Speaker 3: contingency and all of the structure wrapped up in the
Speaker 3: present moment. So you know, basically we've been constructed on
Speaker 3: our planet over four billion years, and all of that
Speaker 3: history is compactified into a very small volume which we
Speaker 3: call a human being, in a human brain. And so
Speaker 3: I think probably consciousness is somehow fundamental to that structure. Obviously,
Speaker 3: so we don't know yet and we don't know how
Speaker 3: to test for that, but that would be sort of
Speaker 3: my conjecture. And I do think intelligence is also fundamental
Speaker 3: to this process, because intelligence is a mechanism of making
Speaker 3: new possibilities physically realized. And so I give an example
Speaker 3: in the book of Thinking about like rockets. Right, So,
Speaker 3: rockets are fully consistent with the laws of physics. It's
Speaker 3: one of the reasons that we can build them. But
Speaker 3: we imagined them centuries before we learned the rules of
Speaker 3: the universe that enabled us to actually build rockets, and
Speaker 3: it took you know, inventing the laws of gravitation and
Speaker 3: also all kinds of engineering principles before they could become
Speaker 3: a physical actuality on our planet. So they're not forbidden
Speaker 3: by our laws of physics or our universe, but they
Speaker 3: require information over time in the form of evolutionary objects
Speaker 3: constructing other evolutionary objects, things like us intelligent things in
Speaker 3: order to exist at all. And so I think that's
Speaker 3: the key feature of what life is. And so intelligence
Speaker 3: and consciousness seemed deeply imashed in that structure and probably
Speaker 3: pretty fundamental to it.
Speaker 1: So you think if we find advanced civilizations on other
Speaker 1: planets or moons, conversion intelligence might have popped up there, right.
Speaker 3: And I go back and forth about, like, you know,
Speaker 3: specific features of intelligence, like the notions of computation we
Speaker 3: have on this planet being universal or not. Right, So
Speaker 3: there's a you know, it's very in vogue right now
Speaker 3: to think of computation as a fundamental universal principle in
Speaker 3: our universe. And you know, sometimes I think mathematics and
Speaker 3: computation are unique to our planet, just like cell phones
Speaker 3: and TikTok and but then sometimes I don't know. So
Speaker 3: I think intelligence, yes, I think which features we call
Speaker 3: intelligence and associated with it, I'm not I'm not sure
Speaker 3: which ones.
Speaker 1: I'll tell you my favorite example that I've been obsessed
Speaker 1: with lately, which is the first video I saw from Sora,
Speaker 1: which is this text to video generator, is this shot
Speaker 1: of you know, it's sort of a drone shot of
Speaker 1: these waves breaking against this cliff, and it's all AI
Speaker 1: generated from just a simple text. The thing is, when
Speaker 1: you watch the waves, they look perfect as far as
Speaker 1: I can tell. The waves are breaking over the rocks,
Speaker 1: and they're doing the right thing and so on.
Speaker 2: But there's no physics engine in Sora.
Speaker 1: It's just saying, Okay, given this frame, what do I
Speaker 1: expect the next frame would look like? But it doesn't
Speaker 1: know f eqals ma or eagles when I have at squared,
Speaker 1: it doesn't It doesn't know any of that.
Speaker 2: And so the thing I've been obsessed with lately is
Speaker 2: wondering what if.
Speaker 1: We had discovered Sora before we had discovered equations and
Speaker 1: f eqals ma and so on, would we have a
Speaker 1: very different sort of society?
Speaker 3: I think, you know what humans do that still is
Speaker 3: unique to humans, and we haven't really found an AI yet.
Speaker 3: Is this capability of broad explanatory paradigms. Right, So that
Speaker 3: example of Sora might be able to do, you know,
Speaker 3: waves on the beach, and it might separately be able
Speaker 3: to you know, build a pendulum, like give you a
Speaker 3: good animation of a pendulum clock, but it won't be
Speaker 3: able to connect an underlying principle that some you know,
Speaker 3: image of a planet on you know, it's never encountered.
Speaker 3: It would actually be able to predict the accurate physics, right. So,
Speaker 3: and humans could do that in part because we're capable
Speaker 3: of building theories and broad explanations that are very abstract
Speaker 3: and not immediately predictive of the the So I think
Speaker 3: there's a there's a fallacy that science is just about
Speaker 3: also just about prediction.
Speaker 4: It's actually more about explanation.
Speaker 3: And if you look at theories of physics, they always
Speaker 3: do this because they completely reframe the way that we
Speaker 3: think about reality.
Speaker 4: Because you know, when we.
Speaker 3: Understand what's actually the underlying structure, the underlying conceptual foundation
Speaker 3: that turns into a mathematical framework like gravitation, we suddenly
Speaker 3: realize we're living in a universe that you know, like
Speaker 3: the celestial motions are not totally distinct than you know,
Speaker 3: terrestrial motion. These are actually governed by the same principles,
Speaker 3: and the universe gets bigger in some sense when we
Speaker 3: make those kind of leaps, and the same thing with
Speaker 3: quantum foundations or general alativity. All all theories of physics
Speaker 3: have had this kind of thing, and I don't see
Speaker 3: that in AI yet. I think what it does is exciting,
Speaker 3: but I don't see that feature.
Speaker 1: I actually wrote a paper last year I suggested that
Speaker 1: a meaningful measure for intelligence in AI is not the
Speaker 1: Turing test any longer, It's not the loveless test things,
Speaker 1: but instead, can it do scientific discovery of the type
Speaker 1: that humans do all the time, big and small, where
Speaker 1: we say.
Speaker 2: Hey, what if the world were this other way?
Speaker 1: What if we had a totally different frame on this thing,
Speaker 1: and then simulate that out and see if that cashes
Speaker 1: out into anything.
Speaker 2: And most of the time it does not.
Speaker 1: But occasionally we say, you know, where if we had
Speaker 1: this other weird frame on it and we get something
Speaker 1: out of it that makes the universe bigger.
Speaker 3: As you just said, yeah, I totally agree with that,
Speaker 3: but I actually have a little bit of concern in
Speaker 3: that space also, and not for what your argument is.
Speaker 3: It's fantastic. I think that's a good benchmark, but also
Speaker 3: that because people are talking about that kind of thing,
Speaker 3: they're actually thinking that they can use AI to replace
Speaker 3: taking new scientific measurements, and they want to, you know,
Speaker 3: use the data. We have to generate new data so
Speaker 3: we have bigger data to train models on. And all
Speaker 3: I see happening in that future is becoming increasingly coupled
Speaker 3: from reality because most of the ways that we've made
Speaker 3: progress in science are not just the explanation, but new
Speaker 3: ways of measurement and taking seriously like what's happening in
Speaker 3: the lab and folding it in and so it's kind
Speaker 3: of you know, I think, I think the future of
Speaker 3: science and AJAAI is super interesting and how it's going
Speaker 3: to transform things. But I think the critical role of
Speaker 3: metrology and like the science of measurement is you know,
Speaker 3: like really undervalued right now.
Speaker 1: By the way, That's interesting because I have always felt
Speaker 1: and I imagined you would too, that the important part
Speaker 1: to moves forward is new theoretical frameworks, not just more
Speaker 1: data not doing better and more measurements in the lab.
Speaker 2: But we're actually.
Speaker 1: Saying, hey, here's a complete new way to think about
Speaker 1: it that allows us to see it finally. Yeah.
Speaker 3: So one of my favorite examples of that is like
Speaker 3: Einstein working on the special theory or relativity. Right, like
Speaker 3: the data had been along around for a long time
Speaker 3: that the speed of light was constant, nobody want to
Speaker 3: take it seriously. I mean, I think one of Einstein's
Speaker 3: you know, greatest strengths was heat the measurement seriously and
Speaker 3: he's like, what are the consequences of this measurement if
Speaker 3: it's true? And you know, parts of his theory even mathematically,
Speaker 3: had been worked out before we already knew, like Lorenz
Speaker 3: had already come up with the Lorenz transformations, which are
Speaker 3: like the key mathematical structure of the special theory relativity.
Speaker 3: So like both parts already existed, and what Einstein did
Speaker 3: was like, take seriously, you know, the spee light at
Speaker 3: constant and real and use that as an explanation for
Speaker 3: why the Lorentz transformations were necessary explanation for space and time. So,
Speaker 3: you know, I think that's an excellent example what you're.
Speaker 2: Saying, Yeah, that's right.
Speaker 1: Or with the photoelectric effect, which is yeah, that's who
Speaker 1: won a Nobel Prize was was thinking about, hey, what
Speaker 1: if there's just a different. You know what if we
Speaker 1: think about this like packets of light. Everybody was looking
Speaker 1: at the photo electric effect and I'm sure you know,
Speaker 1: all the all the great physicists of that time tried
Speaker 1: to answer and came up with some you know, hypothitis,
Speaker 1: but but none of them were right. But yeah, that's
Speaker 1: the key, is that it requires thinking about things in
Speaker 1: a new way, a new framework, and that's what I
Speaker 1: assert AI is not doing currently. It has no capacity
Speaker 1: to do that except perhaps by accident. It might, you know,
Speaker 1: smush some words together and come up with something, But
Speaker 1: that's very different than coming up with a new framework
Speaker 1: and simulating that and saying, oh, yeah, actually that would
Speaker 1: answer the thing.
Speaker 3: And I think intuition really plays a key role in
Speaker 3: the way that we do science in a way that's
Speaker 3: not captured by predictive algorithms.
Speaker 1: That was my interview with Sarah Walker, theoretical physicist at
Speaker 1: Arizona State University. Personally, I love what she's doing because
Speaker 1: while we don't yet know the answer to how life
Speaker 1: emerges from non lifey stuff around us, she's working to
Speaker 1: build something that we can measure the way you'd measure
Speaker 1: height or weight or length, so we can say, hey,
Speaker 1: if it registers on the scale, that doesn't seem like
Speaker 1: an accident. So that's where we're going to assume that
Speaker 1: there was something more required to put that together than
Speaker 1: simply accident and circumstance. So the race is still on
Speaker 1: to find out how life comes about and all the
Speaker 1: ways that it might go.
Speaker 2: But at least we might have some way of.
Speaker 1: Sniffing out something that would otherwise pass right below our
Speaker 1: noses because it doesn't match our expectation for what life is.
Speaker 1: There are a vast number of possibilities, and we don't
Speaker 1: want to miss life by looking only for the green
Speaker 1: person in the tight jumpsuit with DNA and pointy ears,
Speaker 1: when we might be surrounded by things that encapsulate information
Speaker 1: from big stretches of time before them and qualify in
Speaker 1: some way as life. And maybe someday we'll discover that
Speaker 1: there are all kinds of life that would otherwise be
Speaker 1: invisible to us, but we are surround founded by it,
Speaker 1: but without the right framework, we simply hadn't noticed. Go
Speaker 1: to Eagleman dot com slash podcasts for more information and
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Speaker 1: I'm David Eagleman and this is Inner Cosmos.