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Speaker 1: Daniel, it's good to see you. I have a question

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Speaker 1: that I have been dying to ask you. When is

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Speaker 1: physics going to unravel the deep mysteries of the universe?

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Speaker 2: Wow? Right into it? Huh. Unfortunately, we don't have that

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Speaker 2: on our schedule exactly, and it's going to be as

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Speaker 2: long as it takes.

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Speaker 3: You know what.

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Speaker 1: I need to do something important, but I keep putting

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Speaker 1: it off. I put it on a calendar and give

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Speaker 1: myself a deadline. I find that that actually makes it happen,

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Speaker 1: So you should schedule it.

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Speaker 2: All right, let's do it. I'm putting on my calendar.

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Speaker 2: Let's have a zoom meeting to share our ultimate enlightenment

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Speaker 2: about the universe. Have about June twenty twenty nine. That

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Speaker 2: work for you?

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Speaker 3: Uh?

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Speaker 1: You know, I feel like when you come up with

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Speaker 1: budgets and timelines, you always need to multiply by at

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Speaker 1: least three. So let's do something in the twenty forties

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Speaker 1: and I think you'll have.

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Speaker 3: Enough time then. So there it's scheduled. And that was easy.

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Speaker 2: Yeah. Well, you know now I'm worried that scheduling our

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Speaker 2: ultimate enlightened is going to lead us right into the

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Speaker 2: Hitchhiker's Guide to the universe.

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Speaker 3: Trap like I'm gonna forget my towel.

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Speaker 2: That maybe, but more importantly, we might get the answer

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Speaker 2: and have no idea what the question was.

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Speaker 4: Yep, yep, that's a tough one.

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Speaker 2: Hi. I'm Daniel. I'm a particle physicist and a professor

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Speaker 2: at U c Irvine, and I never forget my towel.

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Speaker 1: I'm Kelly Wiersmith, and my kids are always annoyed with

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Speaker 1: me because I'm the only mom at the pool who

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Speaker 1: always forgets the towels. And I'm a junct faculty at

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Speaker 1: Race University.

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Speaker 2: How can you be forgetting towels? I mean, you have

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Speaker 2: these young kids, they're always making messes. I mean everybody's kids,

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Speaker 2: not yours a particular. You gotta just learn to bring

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Speaker 2: the towel wherever you go.

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Speaker 1: Right, I am resistant to learning. I guess I should

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Speaker 1: know by now, but I never All the other moms

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Speaker 1: have the big bags and they got snacks and goldfish.

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Speaker 3: My kids are always like, where are the goldfish?

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Speaker 1: Everybody else has goldfish, and I'm like, tell it to

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Speaker 1: your shrinking a couple of.

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Speaker 3: Years, kid, I'm sorry.

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Speaker 2: At least I have something to complain about, right. My

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Speaker 2: wife has one of those big bags, but she doesn't

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Speaker 2: just have snacks and goldfish in it. She's got all

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Speaker 2: sorts of random crap in there. And my kids are

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Speaker 2: always making fun of her for it until the moment

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Speaker 2: where they're like, hey, mom, wait, do you have chapstick

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Speaker 2: or do you have a spoon, And she's like, of

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Speaker 2: course I do, and she digs it out of a

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Speaker 2: bag and then she's like the savior.

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Speaker 3: Mom to the rescue.

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Speaker 2: Moms are the best, absolutely and so Welcome to the

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Speaker 2: podcast that celebrates moms but also asks the deepest questions

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Speaker 2: in the universe. We want to know how everything works,

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Speaker 2: where it all came from, how it all can possibly

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Speaker 2: make sense to our squishy little brains. Welcome to Daniel

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Speaker 2: and Jorge Explain the Universe, a production of iHeartRadio.

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Speaker 1: So today we're going to be talking about a topic

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Speaker 1: that's near and dear to my heart. I've spent many

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Speaker 1: hours arguing over this question with friends, but I'll let

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Speaker 1: you go ahead and introduce it. I'm just just wanted

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Speaker 1: to preface that I'm excited.

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Speaker 2: On this podcast. We talk about some of the deepest

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Speaker 2: questions in the universe. How is everything made, where it

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Speaker 2: all come from what are the tiny little quantum particles?

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Speaker 2: How do they weave themselves together in order to explain

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Speaker 2: this existence? And where possibly did we leave our towels?

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Speaker 2: But today in the podcast, we're going to talk about

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Speaker 2: something maybe even deeper, something much more personal, something closer

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Speaker 2: to our experience, and that's the question of life itself.

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Speaker 2: What is it? How can we talk about it, how

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Speaker 2: can we understand it? And how possibly could we discover

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Speaker 2: it on alien planets?

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Speaker 1: Oh, there's nothing better than talking about biology on a

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Speaker 1: physics podcast.

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Speaker 3: Finally get into the good stuff.

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Speaker 2: With a couple of physicists. Right, and so today on

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Speaker 2: the podcast, we're going to be digging into the question

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Speaker 2: what is the physics of life? And we're gonna be

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Speaker 2: talking to Professor Sarah Amari Walker, author of the recent

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Speaker 2: book Life As No One Knows It, the physics of

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Speaker 2: Life's Emergence. How do you feel about talking about life

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Speaker 2: with two physicists?

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Speaker 1: Kelly wouldn't be my first choice, but no, I'm kidding.

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Speaker 1: I mean I'm very excited to hear a different perspective

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Speaker 1: on the question.

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Speaker 2: Well, I hope you brought a towel because this is

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Speaker 2: gonna be messy. It's always fascinating when physicists try to

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Speaker 2: walk into another field and explain things. And I feel

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Speaker 2: like often we do that because we think maybe there

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Speaker 2: is a simpler explanation, or because we think in these

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Speaker 2: like fundamental grounding in the basic principles of the universe.

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Speaker 2: How would you say? That's typically receives Kelly.

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Speaker 1: So you say fascinating, we say maddening, because so often physicists,

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Speaker 1: you know, seem to think that physics is up here

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Speaker 1: and biology is a few levels below. And if you

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Speaker 1: know physics, you must also know biology and maybe also chemistry,

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Speaker 1: so you can just wade in and solve all the

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Speaker 1: problems that the biologists are too silly to be able

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Speaker 1: to figure out. And so often there's you know, a

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Speaker 1: bit of condescension in the answers. I saw Freeman Dyson

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Speaker 1: give a talk once about group selection that was absolutely infuriating,

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Speaker 1: but because he clearly didn't understand.

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Speaker 3: What we were actually arguing about.

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Speaker 1: But anyway, today's conversation, you know, I read life as

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Speaker 1: no One Knows It by our author who we're talking

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Speaker 1: to today, and I really appreciated that she did not

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Speaker 1: have that condescending biology as easy attitude. She clearly appreciated

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Speaker 1: the nuances and was trying to meld it with physics.

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Speaker 2: As a physicist married to a biologist, I've definitely learned

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Speaker 2: to treat biology with great respect, good and not just

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Speaker 2: for the health of my marriage, but also just intellectually

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Speaker 2: because I appreciate it. And I think, you know, the

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Speaker 2: dirty secret about physicists walking into biology or chemistry is

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Speaker 2: that we became physicists not because we thought biology was

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Speaker 2: too easy, your chemistry was too simple, but because it's

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Speaker 2: too hard. You know, we can think about simple object

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Speaker 2: and put them together to try to describe the fundamental

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Speaker 2: nature of the universe, but now we need like ten

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Speaker 2: to the forty objects to explain like a drop of rain.

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Speaker 2: It's too complicated. I can't think about all of those

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Speaker 2: things at once. That's why I let to boil things

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Speaker 2: down to like one particle touches one other particle, and

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Speaker 2: that's my whole universe.

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Speaker 4: Man.

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Speaker 1: I appreciate that you're trying to clean up the reputation

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Speaker 1: for your community, but I don't buy it at all.

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Speaker 1: But I do think that biology is complicated. You know,

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Speaker 1: we got the human microbiome that didn't solve all the

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Speaker 1: disease related problems we.

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Speaker 3: Thought it was going to solve.

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Speaker 1: Now we're working on the connect dome for the brain

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Speaker 1: and there's just many levels.

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Speaker 3: Man, it's complicated. We deserve respect.

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Speaker 2: Maybe one day we'll have an explanation for the human

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Speaker 2: brain that goes all the way down to the fundamental physics,

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Speaker 2: but not yet. And so to take us on this

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Speaker 2: journey through the physics of life, whether we can understand

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Speaker 2: the nature of life, the meaning of life, how to

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Speaker 2: look for life, and how maybe even to discover life

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Speaker 2: on alien planets. We had a fun conversation with Professor

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Speaker 2: Sarah Amari Walker about her new book Life As No

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Speaker 2: One Knows It. Here's the interview. So then it's my

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Speaker 2: pleasure to welcome the podcast Sarah and Mauri Walker. She's

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Speaker 2: a theoretical physicist and deputy director for the Beyond Center

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Speaker 2: for Fundamental Concepts in Science, as well as a professor

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Speaker 2: at Arizona State University, and she's tackling some really hard

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Speaker 2: questions about the nature of life and consciousness and free

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Speaker 2: will using physics in her new book. Sarah, thank you

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Speaker 2: very much for joining us today.

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Speaker 5: Yeah, I'm terrilled to be here. Thanks for having me

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Speaker 5: we're so glad to have you here.

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Speaker 2: So before we dig into the topic of your book,

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Speaker 2: I just wanted to get to know you a little

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Speaker 2: bit better, especially because you're writing such a fascinating book.

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Speaker 2: You're tackling really big, really hard, almost philosophical questions, but

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Speaker 2: you're using physics as a tool to do it. So

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Speaker 2: take us back to the beginning, like what got you

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Speaker 2: into physics in the first place.

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Speaker 6: I did not know I wanted to be a physicist

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Speaker 6: until I took my first physics class. So most of

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Speaker 6: my childhood I actually thought I was going to be

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Speaker 6: an artist. And I went to community college and I

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Speaker 6: knew at the time I liked science, so I just

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Speaker 6: took all the science classes i could, and I just

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Speaker 6: fell in love with physics. I just think it's absolutely

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Speaker 6: amazing to think about the universe in these really deep,

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Speaker 6: abstract ways and come to understand the world in a

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Speaker 6: way that is almost existentially shocking to humans in some

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Speaker 6: sense because it's so different than.

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Speaker 5: The way that we thought it was.

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Speaker 6: And the set of broad regularities that physics reveals I

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Speaker 6: think are really beautiful, And I guess I was really

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Speaker 6: excited about transforming something about the way that we think

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Speaker 6: about the world and the way that physics does that.

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Speaker 6: So I decided I wanted to be a physicist.

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Speaker 2: Awesome. So we just had an episode recently about thinking

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Speaker 2: like a physicist what that means, and had a little

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Speaker 2: disagreement with Jorge about whether physicists think differently than other scientists.

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Speaker 2: And so you say you're drawn to physics in particular

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Speaker 2: because of the way they think about the world. How

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Speaker 2: is that different? How does a physicist think about the

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Speaker 2: universe different than a biologist?

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Speaker 6: Yeah, and I'm not even sure if it comes down

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Speaker 6: to training or who gets attracted to different fields. So

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Speaker 6: I actually asked this question myself. But for me, I

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Speaker 6: think a lot of the discussion about what physics is

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Speaker 6: is mostly about what physics studies and not what physics

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Speaker 6: is is a discipline, And so for me, when I

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Speaker 6: think about the history of physics and also what I'm

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Speaker 6: trying to do as a physicist moving into territory that's

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Speaker 6: traditionally not thought of as physics, you know, the thread

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Speaker 6: I see there that I think is the commonality of like,

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Speaker 6: what I think the core of physics is is building

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Speaker 6: new and abstract explanations for the world around us. So

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Speaker 6: I think physics to me is getting to like the

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Speaker 6: very root of like the most fundamental explanations, and that

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Speaker 6: process of doing that is you know, very unique to physics.

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Speaker 6: I think is a discipline relative to other sciences. I

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Speaker 6: think other sciences also do that, But I think the

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Speaker 6: kind of training and the way that we're taught to

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Speaker 6: think and trying to embed these sort of abstract universal

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Speaker 6: ideas in mathematics that are so broad, is pretty.

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Speaker 5: Unique to what we call physics.

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Speaker 6: Now, whether it will stay that way and it doesn't

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Speaker 6: become sort of more universal to the rest of science,

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Speaker 6: or even if that's the best way of doing science,

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Speaker 6: as you know, a whole.

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Speaker 5: Other subject of debate.

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Speaker 6: But for me, that's the essence of what physics is

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Speaker 6: and why I still identify as a physicist, even though

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Speaker 6: the problems I study are so different than what has

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Speaker 6: traditionally been studied in physics.

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Speaker 1: When you've taken on a particularly in my mind, complicated

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Speaker 1: question to tackle. So my training is as a biologist,

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Speaker 1: and in grad school, like the thing that you stay

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Speaker 1: up late drinking and talking about is you know, what

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Speaker 1: is life? And how do you define species? Those are

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Speaker 1: like the two questions where at the end, we're all like,

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Speaker 1: I don't know, nature doesn't fit into categories, and we

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Speaker 1: all laugh and go out dancing. And so what different

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Speaker 1: perspective does a physicist have on that question? And why

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Speaker 1: do we need an answer to this question as opposed

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Speaker 1: to the hand wavy nature doesn't fit into nice categories.

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Speaker 1: Let's just move on. Why do we need to do

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Speaker 1: better than that?

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Speaker 6: So I love the resolution that nature doesn't fit into categories,

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Speaker 6: and so so I love that that's like part of

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Speaker 6: the conclusion. I think that's actually a brilliant insight, because

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Speaker 6: I think we have a tendency to put problems in boxes,

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Speaker 6: because certain disciplines might become more adept to answering certain

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Speaker 6: aspects of questions. But there are some questions on the frontier,

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Speaker 6: like what is life that you know as a biologist,

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Speaker 6: maybe you don't need to know the answer to because

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Speaker 6: you can study biology on Earth without ever having a

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Speaker 6: resolution to that question. But this gets to your point

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Speaker 6: that you know there are some questions like the origin

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Speaker 6: of life that require an understanding of what life is,

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Speaker 6: because that is not even a precisely defined question unless

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Speaker 6: we say that there's some category of nature quote unquote

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Speaker 6: that is life that we're trying to explain the origin of.

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Speaker 5: And the other one is alien life are.

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Speaker 6: Designing completely radically new kinds of life, which I think

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Speaker 6: are not really decoupled problems with this idea of like

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Speaker 6: what other forms could life take besides the ones that

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Speaker 6: have evolved on Earth, besides the biology that we know it?

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Speaker 6: And so I think those questions, surprisingly enough, don't seem

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Speaker 6: to have answers that fall just within the discipline of

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Speaker 6: biology as it's developed, because of exactly what you're pointing out,

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Speaker 6: that the boundaries of disciplines are kind of historically contingent,

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Speaker 6: and there's a lot of things that necessarily need to

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Speaker 6: come from chemistry or even computer science or physics or

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Speaker 6: all these other different disciplines. And so one thing I've

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Speaker 6: really come to notice in my career is that whatever

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Speaker 6: discussion we need to have about solving that problem doesn't

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Speaker 6: fit in any discipline as it's currently structured, And in

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Speaker 6: some sense, we might need to build a new discipline

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Speaker 6: to really think about this problem, because it's beyond the

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Speaker 6: boundaries of like the current confines of knowledge that we've

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Speaker 6: defined them so far. And that's exciting because it just

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Speaker 6: shows you that disciplines are kind of human centric categories

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Speaker 6: of nature. We might have to rewrite them.

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Speaker 2: Yeah, I mean we might argue, like, what is a

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Speaker 2: physicist anyway?

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Speaker 5: And people exactly that and just redefine that trump too.

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Speaker 5: That sounds good to me.

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Speaker 2: And you begin your really fun book with this question

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Speaker 2: and the sort of shocking suggestion that somebody made that

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Speaker 2: life doesn't exist. You know, if we can't categorize it,

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Speaker 2: if we can't define it, then maybe it doesn't exist

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Speaker 2: in the end. What is your definition of life?

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Speaker 5: Yeah?

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Speaker 6: So in my mind, I usually keep I think a

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Speaker 6: running list of maybe three to ten different definitions for life,

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Speaker 6: because I think pinning yourself to one too early is

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Speaker 6: a bit premature when we don't understand what we're talking about.

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Speaker 6: So usually my process is, you know, I really want

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Speaker 6: to have a theory, like a theory that explains the

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Speaker 6: broad patterns and regularities that we see across living forms

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Speaker 6: and is deep enough to help us understand the original life.

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Speaker 6: That's sort of my modality of thinking about these problems.

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Speaker 6: And so I've spent most of my career trying to

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Speaker 6: figure out what the structure of such a theory would be.

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Speaker 6: And obviously it has to be guided by some concept

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Speaker 6: of what you think life is. So it's a little circular,

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Speaker 6: but you're constantly redefining everything. So I'm often very hesitant

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Speaker 6: to pin one answer when people ask me what.

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Speaker 5: I think life is.

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Speaker 6: I but with all that that caveat, I can give

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Speaker 6: you kind of a conceptual framing of what I think

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Speaker 6: it is, but I wouldn't want to call it a definition.

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Speaker 6: And I think a lot of what the theory that

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Speaker 6: we're working on, in the kinds of experiments are pointing

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Speaker 6: to is that life is something about how information structures matter,

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Speaker 6: cross space and time is one way I say it,

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Speaker 6: but I think in the theory that we're building, it's

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Speaker 6: much more precise to say that life is the mechanism

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Speaker 6: by which the universe generates complexity. And we have a

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Speaker 6: very specific way of thinking about complexity, and it becomes

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Speaker 6: very historically contingent, and so I guess how the universe

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Speaker 6: uses memory that builds complex things in the future might

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Speaker 6: be the way I say it today, and if you

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Speaker 6: ask me tomorrow, I would say something else, because we're

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Speaker 6: still a work in progress about trying to get to

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Speaker 6: the bottom of what it is we're actually talking about.

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Speaker 1: So For a biologist, the argument almost always comes down to, well,

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Speaker 1: our virus is alive or not, so using the definition

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Speaker 1: that you just gave our viruses alive or not and why.

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Speaker 5: Yeah, So I think there's a little bit more nuanced.

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Speaker 6: So usually the way I talk about it is like,

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Speaker 6: are we talking about the physics of life? Are particular

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Speaker 6: instances of things that are living? And it might be like,

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Speaker 6: are you talking about gravitational physics and like the curvature

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Speaker 6: or space time, or are you talking about a gravitational

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Speaker 6: body that was generated by these sort of fundamental mechanisms

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Speaker 6: that we know that our universe works in. And I

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Speaker 6: think there are slightly different categories. So when I say

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Speaker 6: things are life, I mean anything that is the product

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Speaker 6: of an evolutionary process and requires memory and information from

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Speaker 6: the past to be able to actually make that thing

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Speaker 6: exist in the present. And I think viruses are certainly

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Speaker 6: that they require evolution to form, but the sort of

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Speaker 6: active process of generating complexity and generating novelty and contributing

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Speaker 6: to the sort of open ended growth of complexity that

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Speaker 6: we've observed in our biosphere.

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Speaker 5: I think things that do that are alive.

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Speaker 6: And I'm not sure that I would qualify a virus

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Speaker 6: as an individual agent as part of that creative process,

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Speaker 6: but it certainly is when you look at viruses as

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Speaker 6: components of ecological systems, for example. So a lot of

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Speaker 6: the things with issues about life is trying to pick

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Speaker 6: a scale and say this thing is life, when really

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Speaker 6: what you're talking about is a much more abstract universal

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Speaker 6: physics that even enables those things to exist in the

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Speaker 6: first place, to be selected. I think the reason that

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Speaker 6: viruses have been hard is because it's actually a category

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Speaker 6: error to try to partition a boundary and around a

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Speaker 6: virus and say is this a live or not when

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Speaker 6: you really should be looking at the continuity of the

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Speaker 6: evolutionary process and what it constructs.

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Speaker 2: Yeah, fascinating. I don't know that I agree that we

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Speaker 2: need a definition of life, but I do think it's

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Speaker 2: valuable to try, Like I think we need to have

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Speaker 2: the discussion in order to try to figure out what

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Speaker 2: this is like. If we agree or discuss, you know,

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Speaker 2: what life is, that shapes the way we think about

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Speaker 2: how to look for alien life and all these questions.

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Speaker 2: So I think it's very valuable to dig into the question,

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Speaker 2: even if we don't find an answer, and from that perspective.

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Speaker 2: I was really interested in the discussion you had at

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Speaker 2: the beginning of your book about, you know, the sort

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Speaker 2: of philosophy of what life might be. And you were

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Speaker 2: going through this discussion of like panpsychism, and there's this

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Speaker 2: one particular line that jumped out at me, said quote,

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Speaker 2: if life is not a property of matter, and material

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Speaker 2: things are what exists, then life does not exist. I

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Speaker 2: was wondering if you could expand on that thought. You know,

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Speaker 2: it doesn't it sort of ignore the possibility that life

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Speaker 2: could just be an emergent phenomenon, as you said, an

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Speaker 2: arrangement and complexity of basic bits that are not alive.

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Speaker 5: Yeah.

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Speaker 6: So part of the reason that I structured things in

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Speaker 6: specific ways early on was to kind of set up

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Speaker 6: some things that come later in the book. And one

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Speaker 6: thing I've noticed being a physicist trying to build new

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Speaker 6: physics is that we take for granted things as being

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Speaker 6: absolutely true about the universe that were actually invented by

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Speaker 6: human minds trying to correlate the way that their theories

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Speaker 6: behave with things they could actually measure. The example I

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Speaker 6: like to give is to think about mass. It seems

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Speaker 6: so obvious to us that mass is a physical property

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Speaker 6: of objects, and it is a physical property we talk

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Speaker 6: about in our theories of physics because we can measure it,

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Speaker 6: and because Galileo rolling balls down in climbplanes and other

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Speaker 6: people of his generation realized that that was the right

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Speaker 6: variable to construct theories of motion. I think, of course,

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Speaker 6: you can talk about life as just being an emergent property,

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Speaker 6: but you're never going to get to an objective understanding

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Speaker 6: of it as a physical phenomena unless you can tie

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Speaker 6: it to a measurement. And therefore whatever that thing is

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Speaker 6: has to become what we would call a material property

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Speaker 6: in our theories of physics, because now it's something we

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Speaker 6: measure that becomes a variable in our theory. Therefore it's physical.

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Speaker 6: And I think this has been the thing that's really

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Speaker 6: hard about thinking about the nature of life, is it

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Speaker 6: has forever been an epiphenomena and something we couldn't regularize

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Speaker 6: as part of a law of nature because we want

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Speaker 6: to adopt this view that surely it's just these emergent

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Speaker 6: informational patterns, but we can't measure them objectively.

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Speaker 5: And so my point saying that.

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Speaker 6: If you want to reduce life that way, then life

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Speaker 6: doesn't exist because you don't have an objective measurement. You

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Speaker 6: don't have a way of grounding whatever you're talking about

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Speaker 6: and testing it against reality and saying this is the

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Speaker 6: thing that emerges when life emerges.

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Speaker 2: If I could just stop you there, because I'm not

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Speaker 2: sure I'm following. Like, let's take a simpler example. You

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Speaker 2: know of thunderstorm. Thunderstorm is an emergent phenomenon, bubbling up

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Speaker 2: from the you know, the properties of particles and molecules

404
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Speaker 2: and all this kind of stuff. Clearly thunderstorms exist, right,

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Speaker 2: we agree. We can make measurements of them, their intensity,

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Speaker 2: all sorts of stuff. We can ground them, we can

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Speaker 2: write even some you know, mathematical expressions that describe them.

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Speaker 2: In some cases, how can we say thunderstorms exist and

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Speaker 2: we can make physical measurements of thunderstorms, but we can't

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Speaker 2: say the same thing about life?

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Speaker 5: Well, what would be the measurement that you're taking about life?

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Speaker 2: Though?

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Speaker 6: So the question with thunderstorms is it's a good example

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Speaker 6: because most of the measurements you're taking are things like

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Speaker 6: when velocity, you know, the temperature, Like these are like

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Speaker 6: physical measurements you can go in and take, and then

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Speaker 6: when you put those in some model of the thunderstorm,

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Speaker 6: you can actually model the thunderstorm's behavior. And that's same

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Speaker 6: physics works if you go on another planetary body and

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Speaker 6: account for differences in pressure and differences particular climate, you know,

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Speaker 6: in that gravitational field and things like that. The issue

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Speaker 6: with life is, you know, most people want to say that,

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Speaker 6: like when you're talking about chemistry, and like, life is

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Speaker 6: an organizational property of chemistry. When we look at its parts,

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Speaker 6: we don't see the things that we associate to life,

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Speaker 6: and so therefore life is an emergent property of those parts.

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Speaker 6: It's some organizational feature. But the problem is we don't

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Speaker 6: have the rules to go from the atoms and the

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Speaker 6: parts to that organizational feature in a universal way that

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Speaker 6: would allow us to go on another planet and measure

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Speaker 6: that property. It's very subjective the way that we talk

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Speaker 6: about it right now, and so it's okay if it's

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Speaker 6: subjective and not a material property. It might be that

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Speaker 6: there is no law of physics that allows us to

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Speaker 6: understand what life is. And it might be that life

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Speaker 6: is not a universal category of nature. It might just

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Speaker 6: be some weird emergent pattern that emerged on Earth and

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Speaker 6: there's no universality to it. But the argument that I'm

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Speaker 6: interested in, and the one I think that will actually

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Speaker 6: help us find alien life that's out there, because life

441
00:21:02,480 --> 00:21:05,000
Speaker 6: is a universal thing if it is, is that we

442
00:21:05,080 --> 00:21:07,720
Speaker 6: need to figure out what are the objective properties. And

443
00:21:08,000 --> 00:21:11,080
Speaker 6: when you do that, in some sense, you're making that

444
00:21:11,160 --> 00:21:14,639
Speaker 6: property material in a way that it becomes measurable. And

445
00:21:14,680 --> 00:21:16,879
Speaker 6: so that's sort of the interplay, Like life has not

446
00:21:17,000 --> 00:21:19,800
Speaker 6: been a material property. We've had this sort of vitalism

447
00:21:19,840 --> 00:21:22,520
Speaker 6: and the idea of a soul. But the question is

448
00:21:22,520 --> 00:21:26,399
Speaker 6: is that actually something that we can quantify, put into

449
00:21:26,440 --> 00:21:29,119
Speaker 6: a theory and also measure so that we can actually

450
00:21:29,200 --> 00:21:33,119
Speaker 6: say this is a real universal law like feature of

451
00:21:33,119 --> 00:21:33,800
Speaker 6: our universe.

452
00:21:34,160 --> 00:21:36,480
Speaker 1: But so then why go to life does not exist

453
00:21:36,560 --> 00:21:40,200
Speaker 1: as opposed to we don't understand it well enough yet.

454
00:21:40,920 --> 00:21:44,879
Speaker 6: Because the logical conclusion of the way that much of

455
00:21:44,920 --> 00:21:47,040
Speaker 6: the discussion has been is that we should assume life

456
00:21:47,040 --> 00:21:49,560
Speaker 6: does not exist. So in some sense, what I'm trying

457
00:21:49,600 --> 00:21:52,240
Speaker 6: to do is actually provoke, you know, like, if we

458
00:21:52,359 --> 00:21:54,920
Speaker 6: run the way we talk about things to their logical conclusion,

459
00:21:54,920 --> 00:21:57,119
Speaker 6: what are we really saying and is this actually what

460
00:21:57,160 --> 00:21:59,480
Speaker 6: we intend to say or do we want to say

461
00:21:59,520 --> 00:22:02,160
Speaker 6: there's something missing from our descriptions of nature, and maybe

462
00:22:02,200 --> 00:22:04,359
Speaker 6: we need to rethink from first principles what it is

463
00:22:04,359 --> 00:22:07,359
Speaker 6: that we're doing. So I actually think life does exist.

464
00:22:07,400 --> 00:22:10,119
Speaker 6: I was always perplexed that a lot of my colleagues,

465
00:22:10,560 --> 00:22:12,480
Speaker 6: if you really listen to the words they were saying,

466
00:22:12,520 --> 00:22:14,720
Speaker 6: were implying that it does not exist, and some of

467
00:22:14,720 --> 00:22:17,119
Speaker 6: them even saying it outright, that we should just not

468
00:22:17,160 --> 00:22:19,680
Speaker 6: think about the problem of defining life at all. Life

469
00:22:19,680 --> 00:22:22,240
Speaker 6: is not a category of nature. It's all reducible to

470
00:22:22,320 --> 00:22:26,119
Speaker 6: chemistry and physics. And I think that there's something deeply

471
00:22:26,200 --> 00:22:30,000
Speaker 6: missing in what life is and why we keep asking

472
00:22:30,040 --> 00:22:31,960
Speaker 6: this question. So why is it a question we ponder

473
00:22:32,000 --> 00:22:35,280
Speaker 6: in bars at night. It's probably because we feel intrinsically

474
00:22:35,320 --> 00:22:38,119
Speaker 6: we're missing something about, you know, the descriptions of the

475
00:22:38,119 --> 00:22:41,520
Speaker 6: world around us that's pretty fundamental. So that was always

476
00:22:41,560 --> 00:22:44,239
Speaker 6: my perspective. Now that might not be right, but I

477
00:22:44,240 --> 00:22:46,240
Speaker 6: think the way to find out if that's.

478
00:22:46,160 --> 00:22:48,240
Speaker 5: Right is try to go through the process.

479
00:22:48,160 --> 00:22:50,199
Speaker 6: Of building a theory you can test against something you

480
00:22:50,240 --> 00:22:54,040
Speaker 6: can measure, and trying to see if empirically you're actually

481
00:22:54,200 --> 00:22:56,679
Speaker 6: getting the right results, and if you're building a theory

482
00:22:56,680 --> 00:23:00,000
Speaker 6: that is all explanatory of the data that we see

483
00:23:00,040 --> 00:23:01,280
Speaker 6: and the observations we can make.

484
00:23:02,000 --> 00:23:04,480
Speaker 2: Right, So you're not saying I don't exist, or you

485
00:23:04,600 --> 00:23:07,560
Speaker 2: don't exist, or my cat doesn't exist. You're saying that

486
00:23:07,600 --> 00:23:10,840
Speaker 2: we don't have a clear and crisp definition of life

487
00:23:11,160 --> 00:23:13,040
Speaker 2: that lets us do things that we typically do in

488
00:23:13,080 --> 00:23:15,680
Speaker 2: physical theories, like we do with thunderstorms and we do

489
00:23:15,760 --> 00:23:18,280
Speaker 2: with cats, because we can make measurements of them. We

490
00:23:18,320 --> 00:23:21,560
Speaker 2: can't other than just like vaguely talking about sort of

491
00:23:22,080 --> 00:23:24,000
Speaker 2: fuzzy conceptual categories.

492
00:23:24,280 --> 00:23:26,359
Speaker 6: Yeah, I mean, in part, you know, the book is

493
00:23:26,359 --> 00:23:29,000
Speaker 6: an exercise of trying to turn a philosophical question into

494
00:23:29,040 --> 00:23:29,880
Speaker 6: a scientific one.

495
00:23:29,960 --> 00:23:30,280
Speaker 2: Yeah.

496
00:23:30,359 --> 00:23:33,320
Speaker 6: Right, So this has traditionally been a philosophical debate because

497
00:23:33,320 --> 00:23:35,439
Speaker 6: we don't have the things that we can pin the

498
00:23:35,600 --> 00:23:38,119
Speaker 6: debate into measurements to actually go test what it is

499
00:23:38,119 --> 00:23:41,000
Speaker 6: that we're talking about. And I think that's really the

500
00:23:41,040 --> 00:23:44,719
Speaker 6: critical transition that you know, most interesting science starts as

501
00:23:44,720 --> 00:23:49,199
Speaker 6: philosophical questions, and the period where the philosophy transitions to

502
00:23:49,240 --> 00:23:52,160
Speaker 6: science is always deeply interesting because we're asking exactly these

503
00:23:52,160 --> 00:23:54,840
Speaker 6: like really basic questions. It forces you to even ask

504
00:23:54,880 --> 00:23:57,840
Speaker 6: what science is, what is a measurement? What is a theory,

505
00:23:57,960 --> 00:23:59,679
Speaker 6: how do you build a new theory? Like what are

506
00:23:59,680 --> 00:24:01,680
Speaker 6: you even talking about? Ever when we talk about things

507
00:24:01,680 --> 00:24:04,040
Speaker 6: in science. So this is why it's exciting, but it

508
00:24:04,119 --> 00:24:07,879
Speaker 6: is really challenging because you're confronting things that you know,

509
00:24:08,440 --> 00:24:11,359
Speaker 6: we haven't known how to think about, and you're saying,

510
00:24:12,119 --> 00:24:15,000
Speaker 6: let's pin ourselves down and be precise and think about

511
00:24:15,040 --> 00:24:18,040
Speaker 6: it and ask how would we actually quantify and measure

512
00:24:18,080 --> 00:24:20,600
Speaker 6: this thing? And how will we build a theory that

513
00:24:20,640 --> 00:24:23,200
Speaker 6: describes this thing? And if you look at the history

514
00:24:23,200 --> 00:24:25,439
Speaker 6: of science, what excites me about it and why I

515
00:24:25,480 --> 00:24:27,359
Speaker 6: think any of the ideas that we're doing might be

516
00:24:27,359 --> 00:24:29,879
Speaker 6: on the right track is you know, every time that

517
00:24:29,880 --> 00:24:31,919
Speaker 6: that process has happened in the history of physics, we

518
00:24:31,960 --> 00:24:34,440
Speaker 6: come out the other side with a radically different conception

519
00:24:34,520 --> 00:24:37,119
Speaker 6: of what's going on than we had before. And like

520
00:24:37,160 --> 00:24:40,000
Speaker 6: my favorite example is like to think about you know,

521
00:24:40,080 --> 00:24:43,240
Speaker 6: saying terrestrial and celestial motion are the same thing. It's like,

522
00:24:43,320 --> 00:24:45,280
Speaker 6: you know, humans had been around for hundreds of thousands

523
00:24:45,280 --> 00:24:47,040
Speaker 6: of years seeing the stars and the night sky and

524
00:24:47,080 --> 00:24:50,320
Speaker 6: planets moving across the sky, and we never thought like

525
00:24:50,440 --> 00:24:52,720
Speaker 6: that would be you know, like the theory of gravitation,

526
00:24:52,760 --> 00:24:56,919
Speaker 6: it took, you know, centuries of measurement and coming to

527
00:24:57,240 --> 00:25:00,040
Speaker 6: you know, track the regularities of heavenly motions and be

528
00:25:00,080 --> 00:25:02,800
Speaker 6: able to get clocks that were precise enough timing to

529
00:25:03,320 --> 00:25:07,720
Speaker 6: actually build into an understanding of a theory of motion

530
00:25:07,880 --> 00:25:09,920
Speaker 6: and gravitation that allowed us to look up at this

531
00:25:09,960 --> 00:25:12,679
Speaker 6: guy and be like, oh, those things are actually moving

532
00:25:12,720 --> 00:25:14,840
Speaker 6: in the same way that things on Earth move. I mean,

533
00:25:14,880 --> 00:25:17,760
Speaker 6: these are radical conceptual leaps that our species has taken,

534
00:25:17,800 --> 00:25:19,520
Speaker 6: and I think to think that we're done doing that

535
00:25:19,640 --> 00:25:22,240
Speaker 6: is really premature. So I get excited about life and

536
00:25:22,240 --> 00:25:24,440
Speaker 6: when people say, well, isn't it just a pattern of motions,

537
00:25:24,440 --> 00:25:25,800
Speaker 6: and I'm like, well, of course it is. But we've

538
00:25:25,840 --> 00:25:29,000
Speaker 6: explained lots of those before in really deep and fundamental ways,

539
00:25:29,040 --> 00:25:30,119
Speaker 6: so maybe we should try again.

540
00:25:30,400 --> 00:25:33,679
Speaker 2: All right, I have lots more questions about this squishy topic,

541
00:25:33,720 --> 00:25:49,280
Speaker 2: but first let's take a quick break. Okay, we're back,

542
00:25:49,320 --> 00:25:51,720
Speaker 2: and we're trying to sort through the slimy questions of

543
00:25:51,800 --> 00:25:55,399
Speaker 2: the physics of life with Professor Sarah Amari Walker, author

544
00:25:55,440 --> 00:25:58,440
Speaker 2: of the book Life As No One Knows It Well

545
00:25:58,440 --> 00:26:01,719
Speaker 2: in terms of taking like a radical conceptual philosophical leaps.

546
00:26:01,880 --> 00:26:04,439
Speaker 2: I was very excited to see you open the door

547
00:26:04,960 --> 00:26:08,639
Speaker 2: to getting rid of reductionism. I mean, especially as a physicist,

548
00:26:09,000 --> 00:26:12,080
Speaker 2: you know, and as you described earlier, physics is so

549
00:26:12,480 --> 00:26:15,280
Speaker 2: ingrained in the idea of, like, let's find the microscopic

550
00:26:15,320 --> 00:26:17,879
Speaker 2: explanation for everything, start with what we hope is the

551
00:26:17,880 --> 00:26:21,080
Speaker 2: fundamental and everything will bubble up from there somehow dot

552
00:26:21,119 --> 00:26:24,280
Speaker 2: dot dot. Right. Leave that as an exercise for the engineers.

553
00:26:24,720 --> 00:26:28,520
Speaker 2: But in your book you actually consider the other approach,

554
00:26:28,600 --> 00:26:31,720
Speaker 2: the idea that like, maybe not everything is determined from

555
00:26:31,720 --> 00:26:35,720
Speaker 2: the smallest bits. Maybe what we see as like emergent

556
00:26:35,760 --> 00:26:39,679
Speaker 2: phenomena different scales or actually have their own different fundamental

557
00:26:39,720 --> 00:26:42,679
Speaker 2: description that like, you know, the universe isn't controlled by

558
00:26:42,760 --> 00:26:44,879
Speaker 2: the tiniest Can you talk a little bit about that.

559
00:26:44,920 --> 00:26:47,440
Speaker 2: I think that's probably a very unfamiliar concept for our

560
00:26:47,480 --> 00:26:50,119
Speaker 2: listeners who are used to, especially on this podcast, hearing

561
00:26:50,200 --> 00:26:52,879
Speaker 2: us talk about how tiny particles weave together to make

562
00:26:52,920 --> 00:26:53,520
Speaker 2: the universe.

563
00:26:54,480 --> 00:26:57,320
Speaker 6: Yeah, And I also love that view of reality. I

564
00:26:57,320 --> 00:26:59,639
Speaker 6: think it's like incredibly romantic, and I was trained in

565
00:26:59,640 --> 00:27:03,639
Speaker 6: that trich But thinking about life and really trying to

566
00:27:04,080 --> 00:27:06,639
Speaker 6: ask the question whether there were universal laws of life

567
00:27:06,680 --> 00:27:08,800
Speaker 6: like that speaks to me that we're looking for something

568
00:27:08,800 --> 00:27:12,200
Speaker 6: fundamental because it has to be universal and broadly explanatory

569
00:27:12,200 --> 00:27:15,760
Speaker 6: of any life in the universe, you start to ask

570
00:27:15,880 --> 00:27:18,800
Speaker 6: questions about the nature of what's fundamental. And as I

571
00:27:18,840 --> 00:27:20,720
Speaker 6: already alluded to before, a lot of the ways that

572
00:27:20,760 --> 00:27:24,400
Speaker 6: we think about what's fundamental are what things we can

573
00:27:24,520 --> 00:27:26,880
Speaker 6: go in the lab and test that build the structure

574
00:27:26,880 --> 00:27:29,720
Speaker 6: of our theories. And so some of the most precise

575
00:27:29,760 --> 00:27:33,600
Speaker 6: theories we have are these ones about microscopical physical motions,

576
00:27:34,600 --> 00:27:37,360
Speaker 6: but it doesn't mean that they explain everything. And one

577
00:27:37,359 --> 00:27:39,640
Speaker 6: of the points that I make in the book, which

578
00:27:39,680 --> 00:27:43,320
Speaker 6: is related to this sort of evolutionary progress of knowledge

579
00:27:43,320 --> 00:27:45,880
Speaker 6: that we've been talking about about, like disciplines changing over time,

580
00:27:45,960 --> 00:27:48,600
Speaker 6: is the notion of what's fundamental has actually changed with

581
00:27:48,640 --> 00:27:51,920
Speaker 6: our theories and with our measuring devices, and so I think,

582
00:27:52,480 --> 00:27:54,560
Speaker 6: you know, like the canonical example I like to give

583
00:27:54,600 --> 00:27:56,960
Speaker 6: is to think about atoms, which we thought for a

584
00:27:57,000 --> 00:27:59,280
Speaker 6: long time or indivisible units of matter, until we build

585
00:27:59,280 --> 00:28:01,919
Speaker 6: better technology and we realize they had parts. And so

586
00:28:01,960 --> 00:28:04,560
Speaker 6: I'm not sure that there's really a bottom to that process.

587
00:28:05,160 --> 00:28:07,800
Speaker 6: If string theory is right, obviously all the elementary particles

588
00:28:07,800 --> 00:28:09,680
Speaker 6: and things we think are you know, the full description

589
00:28:09,720 --> 00:28:13,240
Speaker 6: and reality are not right, but we can't validate theories

590
00:28:13,240 --> 00:28:16,800
Speaker 6: that go smaller because we don't have the technology yet.

591
00:28:17,600 --> 00:28:21,000
Speaker 6: So you know, that becomes a horizon of our current

592
00:28:21,160 --> 00:28:25,000
Speaker 6: understanding of reality, not something that's intrinsic to reality itself.

593
00:28:26,280 --> 00:28:26,760
Speaker 5: And if you.

594
00:28:26,720 --> 00:28:29,840
Speaker 6: Flip that around and you look at what you're trying

595
00:28:29,840 --> 00:28:32,600
Speaker 6: to do building a theory of life, life is built

596
00:28:32,640 --> 00:28:35,520
Speaker 6: out of these what we think are fundamental building blocks.

597
00:28:36,280 --> 00:28:37,959
Speaker 6: But the kinds of things that we want to understand

598
00:28:38,000 --> 00:28:41,360
Speaker 6: about life are much more about how the universe builds

599
00:28:41,400 --> 00:28:45,320
Speaker 6: complexity out of small parts. And it is the case

600
00:28:45,360 --> 00:28:48,280
Speaker 6: that if we can think about things that we can

601
00:28:48,720 --> 00:28:51,440
Speaker 6: measure there and build theories there, there's no reason to

602
00:28:51,440 --> 00:28:54,200
Speaker 6: think they're not just as fundamental as these other descriptions

603
00:28:54,200 --> 00:28:57,040
Speaker 6: of nature. So that's sort of like the baseline philosophy

604
00:28:57,080 --> 00:29:00,560
Speaker 6: I'm operating from. But the sort of core of your question,

605
00:29:00,560 --> 00:29:03,840
Speaker 6: I think is more about the emergence reductionism debate, not

606
00:29:03,920 --> 00:29:06,400
Speaker 6: the philosophy of measurement and what's fundamental. But I think

607
00:29:06,480 --> 00:29:09,440
Speaker 6: like those things are coupled, so I wanted to preface it,

608
00:29:09,520 --> 00:29:14,520
Speaker 6: But the emergence reductionism, you know, Phil Anderson had this

609
00:29:14,520 --> 00:29:16,400
Speaker 6: great essay which a lot of people have read and

610
00:29:16,480 --> 00:29:18,400
Speaker 6: love about this idea of more is different. You know,

611
00:29:18,480 --> 00:29:20,920
Speaker 6: even if you had that fundamental description, it doesn't mean

612
00:29:20,960 --> 00:29:24,480
Speaker 6: that as you go to these other layers like biology

613
00:29:24,800 --> 00:29:27,400
Speaker 6: and mind and technology, you're going to actually be able

614
00:29:27,400 --> 00:29:30,479
Speaker 6: to recover all the features of them. And so this

615
00:29:30,560 --> 00:29:33,880
Speaker 6: has been deeply perplexing. And what I suggest in the

616
00:29:33,920 --> 00:29:36,720
Speaker 6: book is one of the reasons you can't go between

617
00:29:36,760 --> 00:29:40,160
Speaker 6: scales is there actually are separate laws that describe the

618
00:29:40,240 --> 00:29:42,240
Speaker 6: idea of a hierarchy in the first place, that the

619
00:29:42,320 --> 00:29:45,360
Speaker 6: universe is actually constructing complexity, and that time needs to

620
00:29:45,400 --> 00:29:48,880
Speaker 6: be a component of that process. So if you remove

621
00:29:49,880 --> 00:29:54,080
Speaker 6: you know, evolutionary time, you know, you can talk about

622
00:29:54,400 --> 00:29:57,320
Speaker 6: me being an emergent property of my atoms, but I've

623
00:29:57,320 --> 00:29:59,760
Speaker 6: missed almost all of the physics that's in my body

624
00:30:00,080 --> 00:30:02,240
Speaker 6: and like the product of four billion years of evolution,

625
00:30:02,800 --> 00:30:04,239
Speaker 6: And so if I want to talk about me as

626
00:30:04,240 --> 00:30:07,480
Speaker 6: a fundamental structure, I need to talk about that feature,

627
00:30:08,080 --> 00:30:11,560
Speaker 6: not the atoms in my body. And so it's really

628
00:30:11,600 --> 00:30:13,800
Speaker 6: trying to invert the nature of like what is the

629
00:30:13,840 --> 00:30:16,720
Speaker 6: thing that actually explains this? You can say I'm an

630
00:30:16,760 --> 00:30:20,600
Speaker 6: emergent property, but it doesn't explain from those laws, those

631
00:30:20,640 --> 00:30:23,080
Speaker 6: lower level laws, how I got here and why I exist.

632
00:30:23,280 --> 00:30:25,600
Speaker 2: But does that mean that there is no explanation that

633
00:30:25,680 --> 00:30:27,800
Speaker 2: you have to have fundamental laws at every scale or

634
00:30:27,800 --> 00:30:31,080
Speaker 2: does it just mean those explanations eskeep us currently or

635
00:30:31,120 --> 00:30:34,040
Speaker 2: our current ability to do those calculations, and in some

636
00:30:34,320 --> 00:30:37,600
Speaker 2: future where we have an amazing supercomputer, we can model

637
00:30:37,640 --> 00:30:38,920
Speaker 2: everything from the tiniest bits.

638
00:30:39,480 --> 00:30:43,240
Speaker 6: I think it's both of the last things you said.

639
00:30:44,200 --> 00:30:49,240
Speaker 6: So I think there you cannot produce things like us

640
00:30:49,400 --> 00:30:51,880
Speaker 6: from the current structure the laws of physics. I don't

641
00:30:51,880 --> 00:30:54,160
Speaker 6: even think if you had a super massive supercomputer you

642
00:30:54,200 --> 00:30:56,880
Speaker 6: could do it. And a simple reason to cite that

643
00:30:57,080 --> 00:30:59,760
Speaker 6: is it would require more computation than is available in

644
00:30:59,800 --> 00:31:03,080
Speaker 6: all the resources of the entire universe, and yet the

645
00:31:03,160 --> 00:31:06,240
Speaker 6: universe builds things like us. And so I think that

646
00:31:06,400 --> 00:31:10,040
Speaker 6: right there suggests that something fundamental is missing, because you

647
00:31:10,080 --> 00:31:12,320
Speaker 6: could say, in principle, you could simulate it, and you

648
00:31:12,320 --> 00:31:15,920
Speaker 6: could generate our conversation that we're having right now, but

649
00:31:16,040 --> 00:31:18,800
Speaker 6: actually in principle is not in principle because it's not

650
00:31:18,800 --> 00:31:21,720
Speaker 6: even physically possible. So those things, to me suggest that

651
00:31:21,760 --> 00:31:25,360
Speaker 6: there's a huge gap in understanding. But I also think

652
00:31:26,320 --> 00:31:32,440
Speaker 6: fundamentally that the physics of what describes living things is

653
00:31:32,480 --> 00:31:36,920
Speaker 6: not encapsulated in the physics that we have of gravitational

654
00:31:37,520 --> 00:31:40,160
Speaker 6: fields or elementary particles or any sort of state of

655
00:31:40,160 --> 00:31:42,480
Speaker 6: the art in modern physics departments. I think it's just

656
00:31:42,640 --> 00:31:45,320
Speaker 6: not in those equations. And the reason I think it's

657
00:31:45,320 --> 00:31:47,320
Speaker 6: not in those equations is because life is very much

658
00:31:47,360 --> 00:31:51,680
Speaker 6: about the causation and time that's built into physical objects

659
00:31:51,680 --> 00:31:54,240
Speaker 6: that are complex. And if you think about what the

660
00:31:54,320 --> 00:31:59,160
Speaker 6: laws of physics revealed, they are often designed for specific problems,

661
00:31:59,520 --> 00:32:02,320
Speaker 6: and they tell you what's universal about a set of

662
00:32:02,440 --> 00:32:06,880
Speaker 6: questions like motion, for example, Like all moving objects you know,

663
00:32:06,960 --> 00:32:10,960
Speaker 6: can be described by mass and acceleration and you don't

664
00:32:10,960 --> 00:32:12,920
Speaker 6: care about the color of them, or how those objects

665
00:32:12,920 --> 00:32:15,240
Speaker 6: feel or other things. But that doesn't mean that those

666
00:32:15,320 --> 00:32:20,320
Speaker 6: laws explain everything about every object. And so you know,

667
00:32:20,360 --> 00:32:22,720
Speaker 6: the question is how many kinds of laws.

668
00:32:22,480 --> 00:32:23,600
Speaker 5: Of physics do we need?

669
00:32:24,040 --> 00:32:26,720
Speaker 6: What's the sort of universal set of things that they cover?

670
00:32:26,880 --> 00:32:30,400
Speaker 6: And I think life is presenting some real challenges for

671
00:32:30,640 --> 00:32:33,280
Speaker 6: the sort of current paradigm that we have in really

672
00:32:33,320 --> 00:32:34,240
Speaker 6: fundamental ways.

673
00:32:34,880 --> 00:32:38,400
Speaker 1: Again, as the biologist in the conversation, so I feel

674
00:32:38,400 --> 00:32:41,360
Speaker 1: like what I'm hearing is that we don't really understand

675
00:32:41,360 --> 00:32:44,880
Speaker 1: the physics stuff, but we know that life is something

676
00:32:44,960 --> 00:32:45,960
Speaker 1: that comes about through.

677
00:32:45,800 --> 00:32:46,800
Speaker 3: The process of evolution.

678
00:32:47,280 --> 00:32:50,560
Speaker 1: So I feel like we're back in an evolutionary biology lab. Yes,

679
00:32:51,200 --> 00:32:54,800
Speaker 1: how how does a physicist study it? Differently? Like is

680
00:32:54,840 --> 00:32:59,280
Speaker 1: the question what process results in something that natural selection

681
00:32:59,360 --> 00:33:02,680
Speaker 1: can then act? Like when when we, you know, put

682
00:33:02,680 --> 00:33:05,280
Speaker 1: the pedal to the metal or whatever, Like what what

683
00:33:05,320 --> 00:33:08,080
Speaker 1: do we do in a lab or on a board

684
00:33:08,120 --> 00:33:09,000
Speaker 1: for with equations?

685
00:33:09,080 --> 00:33:09,600
Speaker 3: That's different?

686
00:33:09,880 --> 00:33:13,760
Speaker 6: So this is a great question because ultimately, like Daniel's question,

687
00:33:14,080 --> 00:33:17,120
Speaker 6: can you know what will ultimately resolve it is? Does

688
00:33:17,160 --> 00:33:20,520
Speaker 6: providing a new explanation provide any new experimental tests and

689
00:33:20,560 --> 00:33:22,040
Speaker 6: things we couldn't do otherwise?

690
00:33:23,000 --> 00:33:25,360
Speaker 5: Because it doesn't. I could tell you, you know, I could.

691
00:33:25,200 --> 00:33:27,840
Speaker 6: Sit here all day arguing that there's other laws of

692
00:33:27,840 --> 00:33:31,120
Speaker 6: physics in life, and you know you could nod your head. Okay, Sarah,

693
00:33:31,200 --> 00:33:32,920
Speaker 6: but show me the proof, right, And I've been doing

694
00:33:32,920 --> 00:33:34,840
Speaker 6: this most of my career because you know, I have

695
00:33:34,920 --> 00:33:36,760
Speaker 6: like some conviction it's there, but we have to do

696
00:33:36,760 --> 00:33:38,400
Speaker 6: the hard work as scientists and show that.

697
00:33:38,400 --> 00:33:39,479
Speaker 5: It's useful for something.

698
00:33:40,520 --> 00:33:44,320
Speaker 6: And I think I think to your question, the challenge is,

699
00:33:44,920 --> 00:33:49,040
Speaker 6: you know, for the most part, we think about evolution

700
00:33:49,160 --> 00:33:53,160
Speaker 6: and selection as being things that life does. But that

701
00:33:53,200 --> 00:33:55,880
Speaker 6: doesn't allow us to explain the origin of life because

702
00:33:56,400 --> 00:33:59,920
Speaker 6: it has to be some spontaneous fluctuation with no machan

703
00:34:00,080 --> 00:34:03,800
Speaker 6: is a right and so, or it's just a rare fluke, right,

704
00:34:03,800 --> 00:34:05,720
Speaker 6: And then if it's a rare fluke, then you know,

705
00:34:05,760 --> 00:34:08,240
Speaker 6: none of this discussion is necessary because it's just something

706
00:34:08,280 --> 00:34:10,920
Speaker 6: that happened and there's no you know, explanation for it.

707
00:34:10,920 --> 00:34:12,640
Speaker 5: It was just, you know, a rare fluke event.

708
00:34:12,680 --> 00:34:14,439
Speaker 6: And I think this is one of the challenges because

709
00:34:14,440 --> 00:34:17,040
Speaker 6: that allows you know, intelligent design and other things to

710
00:34:17,080 --> 00:34:20,319
Speaker 6: be equivalent explanations to the scientific one, because we don't

711
00:34:20,360 --> 00:34:23,719
Speaker 6: have an explanation. So if you really want to explain it,

712
00:34:23,760 --> 00:34:25,520
Speaker 6: you kind of have to assume the original life is

713
00:34:25,520 --> 00:34:28,880
Speaker 6: itself a process of selection and evolution, so it's the

714
00:34:28,920 --> 00:34:31,920
Speaker 6: product of those kind of mechanisms, which means you need

715
00:34:31,960 --> 00:34:36,600
Speaker 6: an understanding of evolution that doesn't require a cellular architecture.

716
00:34:37,200 --> 00:34:39,000
Speaker 5: And this is the main challenge, right, So.

717
00:34:39,040 --> 00:34:44,760
Speaker 6: Before replication, before natural selection as we understand it now

718
00:34:44,920 --> 00:34:47,840
Speaker 6: in genes or the way it operates in biological populations

719
00:34:48,120 --> 00:34:51,280
Speaker 6: out of chemistry. How does an evolutionary system get constructed?

720
00:34:52,080 --> 00:34:55,439
Speaker 6: And so this is really the question that we're trying

721
00:34:55,440 --> 00:34:57,520
Speaker 6: to ask, is how do you get complexity when there

722
00:34:57,560 --> 00:35:01,520
Speaker 6: is none? And so so that's where we need a

723
00:35:01,520 --> 00:35:04,520
Speaker 6: new paradigm, because we need a mechanism of selection that

724
00:35:04,640 --> 00:35:09,480
Speaker 6: operates starting from simple molecules building into the complexity of life.

725
00:35:09,520 --> 00:35:11,440
Speaker 6: And that's really the theory that we're working on. This

726
00:35:11,480 --> 00:35:14,680
Speaker 6: assembly theory is really an approach to talking about selection

727
00:35:15,440 --> 00:35:18,440
Speaker 6: in the absence of like wind selection emerges, How to

728
00:35:18,520 --> 00:35:23,280
Speaker 6: selection actually start and how to selection build evolutionary systems

729
00:35:23,280 --> 00:35:25,920
Speaker 6: that we would recognize as evolving things. And so it's

730
00:35:25,920 --> 00:35:29,160
Speaker 6: suggesting a much more universal structure to the evolutionary process

731
00:35:29,719 --> 00:35:32,759
Speaker 6: then the particular things that we're selected and involved on

732
00:35:32,840 --> 00:35:36,440
Speaker 6: earth to understanding what are the general principles of the

733
00:35:36,560 --> 00:35:40,000
Speaker 6: kinds of systems that chemistry could generate that could lead

734
00:35:40,040 --> 00:35:42,240
Speaker 6: to this process of evolution that we recognize.

735
00:35:43,320 --> 00:35:44,760
Speaker 5: That's the question we're trying to answer.

736
00:35:45,680 --> 00:35:48,880
Speaker 6: And I think that one really does demand new physical

737
00:35:48,920 --> 00:35:52,640
Speaker 6: principles because you're asking out of I mean, people really

738
00:35:52,640 --> 00:35:55,319
Speaker 6: don't understand how big chemical space is. It is like

739
00:35:55,640 --> 00:35:58,160
Speaker 6: astronomically large. We also do a lot of stuff with

740
00:35:58,200 --> 00:36:00,480
Speaker 6: drug design with the same theories that trying to sell

741
00:36:00,480 --> 00:36:02,640
Speaker 6: the original life, which is kind of crazy. So I

742
00:36:02,920 --> 00:36:05,839
Speaker 6: deal with like you know, pharmaceutical drugs and this kind

743
00:36:05,880 --> 00:36:07,880
Speaker 6: of stuff. But like when cheminformatics go in and they

744
00:36:07,880 --> 00:36:09,960
Speaker 6: want to estimate the size of the chemical space they

745
00:36:09,960 --> 00:36:12,280
Speaker 6: have to search to look for new drug like properties,

746
00:36:12,320 --> 00:36:16,680
Speaker 6: it is insane. It's not small, it's insanely large, you know.

747
00:36:16,719 --> 00:36:19,719
Speaker 6: I think a really good example is like taxol is

748
00:36:19,760 --> 00:36:21,160
Speaker 6: a molecule I use a lot of times when I

749
00:36:21,160 --> 00:36:23,560
Speaker 6: give lectures that I picked up from my colleged Lee Kronin.

750
00:36:23,880 --> 00:36:26,040
Speaker 6: That molecule has an molecrooid of about eight hundred and

751
00:36:26,040 --> 00:36:28,960
Speaker 6: fifty three, you know, I think it has like forty

752
00:36:29,080 --> 00:36:33,400
Speaker 6: seven carbon atoms or fifty three or something that oxygen. Anyway, like,

753
00:36:33,400 --> 00:36:35,759
Speaker 6: if you wanted to do all the molecules with that

754
00:36:35,840 --> 00:36:38,279
Speaker 6: chemical formula alone, it would fill a volume of one

755
00:36:38,280 --> 00:36:41,920
Speaker 6: point five universes. So if you think about a planet

756
00:36:42,160 --> 00:36:48,200
Speaker 6: generating chemical chemistry in an unconstrained way, no selection, the

757
00:36:48,239 --> 00:36:51,400
Speaker 6: space of molecules that could be you know, just randomly

758
00:36:51,440 --> 00:36:54,960
Speaker 6: synthesized is so astronomically large, you would never expect anything

759
00:36:55,000 --> 00:36:58,360
Speaker 6: complex to recur twice. And so this is kind of

760
00:36:58,360 --> 00:37:01,120
Speaker 6: a key argument of the way that we constructed the theory.

761
00:37:01,160 --> 00:37:04,319
Speaker 6: When you start to see things that involve a lot

762
00:37:04,320 --> 00:37:06,759
Speaker 6: of constraints in the space of possibilities to get these

763
00:37:06,800 --> 00:37:11,920
Speaker 6: really complex, really improbable objects with a high abundance that

764
00:37:11,920 --> 00:37:16,360
Speaker 6: they're happening a lot, that's evidence of selection happening, and

765
00:37:16,400 --> 00:37:19,000
Speaker 6: that selection is actually the physics generating those objects. But

766
00:37:19,000 --> 00:37:20,759
Speaker 6: it's got to be much deeper than what we just

767
00:37:20,800 --> 00:37:23,439
Speaker 6: see and involved architectures that we have, like with the cell,

768
00:37:23,480 --> 00:37:25,680
Speaker 6: because that comes fairly late in the original life process.

769
00:37:25,920 --> 00:37:28,399
Speaker 2: So I understand that the space is very large, right,

770
00:37:28,440 --> 00:37:31,680
Speaker 2: Obviously there's lots of different combinations. Chemistry is complicated. But

771
00:37:31,800 --> 00:37:35,560
Speaker 2: how do we know what's improbable or what's unusual because

772
00:37:35,640 --> 00:37:38,160
Speaker 2: the space is so large and we haven't explored it, right,

773
00:37:38,200 --> 00:37:40,920
Speaker 2: And you say, for example, like the existence of rockets

774
00:37:40,960 --> 00:37:43,439
Speaker 2: in the universe is a sign of like conscious thought

775
00:37:43,520 --> 00:37:45,600
Speaker 2: or whatever, But you know, how do we know them

776
00:37:45,800 --> 00:37:47,279
Speaker 2: that that's the case? How do we know that other

777
00:37:47,440 --> 00:37:50,600
Speaker 2: arrangements that our particular planet didn't explore don't lead to

778
00:37:50,680 --> 00:37:54,520
Speaker 2: greater complexity or more interesting things existing in the universe.

779
00:37:54,960 --> 00:37:57,279
Speaker 6: So your question is a good one, and I think

780
00:37:57,360 --> 00:38:00,160
Speaker 6: a lot of us have sort of embedded in the

781
00:38:00,160 --> 00:38:02,040
Speaker 6: way that we think about the world. And this actually

782
00:38:02,040 --> 00:38:03,880
Speaker 6: comes from the way that we think about physics. It's

783
00:38:03,960 --> 00:38:07,920
Speaker 6: sort of a heritage legacy actually from the eighteen hundreds

784
00:38:08,000 --> 00:38:10,560
Speaker 6: and the development of statistical mechanics and the idea of

785
00:38:10,560 --> 00:38:14,040
Speaker 6: spontaneous fluctuation. We have an idea in our minds that

786
00:38:14,600 --> 00:38:20,080
Speaker 6: anything of arbitrarily complexity can spontaneously fluctuate into existence. And

787
00:38:20,120 --> 00:38:22,320
Speaker 6: this is the whole impetus of the Boltzmant brain argument,

788
00:38:22,360 --> 00:38:24,960
Speaker 6: which actually was proposed by Eddington. Originally is kind of

789
00:38:24,960 --> 00:38:28,279
Speaker 6: a mocking of Boltzmann's ideas, but then became something that

790
00:38:28,400 --> 00:38:30,680
Speaker 6: physicists took very seriously and tried to put in our

791
00:38:30,680 --> 00:38:35,600
Speaker 6: cosmological models. And so the challenge there is, of course,

792
00:38:35,640 --> 00:38:38,480
Speaker 6: we can say, you know, a planet can make an

793
00:38:38,600 --> 00:38:42,239
Speaker 6: arbitrarily complex molecule, right. I can make that statement and

794
00:38:42,320 --> 00:38:45,680
Speaker 6: it seems intuitively logical. But if I said, you know,

795
00:38:45,800 --> 00:38:48,440
Speaker 6: Mars is going to generate a cell phone tomorrow, you

796
00:38:48,480 --> 00:38:50,560
Speaker 6: would kind of laugh at me, right, like that's a

797
00:38:50,560 --> 00:38:53,600
Speaker 6: silly statement. Is there really a chance that we could

798
00:38:53,719 --> 00:38:55,920
Speaker 6: just find the planet Mars generating a cell phone, and

799
00:38:56,000 --> 00:38:58,880
Speaker 6: like not a cell phone, but just something equivalent amount

800
00:38:59,000 --> 00:39:05,080
Speaker 6: of organization and evolutionary processes, Like a cell phone takes

801
00:39:05,080 --> 00:39:07,080
Speaker 6: four billion years to make on a planet. It takes

802
00:39:07,080 --> 00:39:09,440
Speaker 6: a lot of selection to get to that very specific object.

803
00:39:09,719 --> 00:39:12,600
Speaker 6: It's really designed for our biology. The technology is built

804
00:39:12,600 --> 00:39:16,560
Speaker 6: on our planetary resources. Like everything about that object is

805
00:39:17,400 --> 00:39:20,440
Speaker 6: a direct consequence of the fact that we've had four

806
00:39:20,480 --> 00:39:23,440
Speaker 6: billion years of evolution along a specific trajectory on our planet.

807
00:39:24,120 --> 00:39:26,400
Speaker 6: And so to assume an object like that can just

808
00:39:26,840 --> 00:39:30,640
Speaker 6: form random chance somewhere in the universe, I think is

809
00:39:30,880 --> 00:39:34,239
Speaker 6: a major it's a major misstep in our reasoning.

810
00:39:33,920 --> 00:39:35,400
Speaker 5: About how reality works.

811
00:39:35,440 --> 00:39:38,080
Speaker 6: We have no evidence that it can actually happen outside

812
00:39:38,080 --> 00:39:41,439
Speaker 6: of evolution, and so a lot of people will try

813
00:39:41,480 --> 00:39:44,560
Speaker 6: to challenge the way that we're building the formalism on

814
00:39:44,640 --> 00:39:47,719
Speaker 6: this idea that something complex can just be made on

815
00:39:47,760 --> 00:39:50,960
Speaker 6: a planet in the absence of evolution and selection. And

816
00:39:51,239 --> 00:39:52,920
Speaker 6: I can just say back to that, like, give me

817
00:39:52,960 --> 00:39:57,400
Speaker 6: the evidence the universe builds an that requires like information

818
00:39:57,440 --> 00:39:59,839
Speaker 6: to specify it, because to me, what that argument when

819
00:39:59,880 --> 00:40:02,680
Speaker 6: it tail is actually the equivalent of intelligent designs, as

820
00:40:02,680 --> 00:40:05,319
Speaker 6: the universe has the design of every object at every

821
00:40:05,360 --> 00:40:09,200
Speaker 6: point in the universe. What I'm suggesting is that selection

822
00:40:09,239 --> 00:40:12,440
Speaker 6: and evolution are required to build information specific to objects

823
00:40:12,440 --> 00:40:14,000
Speaker 6: before they can exist.

824
00:40:13,840 --> 00:40:16,799
Speaker 2: Right, And I agree with that. I'm not arguing that

825
00:40:17,480 --> 00:40:20,080
Speaker 2: cell phones should appear on Mars, so that would be probable,

826
00:40:20,400 --> 00:40:23,319
Speaker 2: and I appreciate that. You know, complexity comes as like

827
00:40:23,360 --> 00:40:25,600
Speaker 2: the tip of the pyramid built on the base of

828
00:40:25,680 --> 00:40:29,120
Speaker 2: like a huge amount of things that came before it. Absolutely,

829
00:40:29,360 --> 00:40:32,279
Speaker 2: But what I'm wondering is whether we can argue that

830
00:40:32,440 --> 00:40:36,480
Speaker 2: life on Earth is unusually complex. We don't know with

831
00:40:36,520 --> 00:40:38,920
Speaker 2: the space of possibilities is maybe if we go out

832
00:40:38,920 --> 00:40:41,840
Speaker 2: in the universe we discover, wow, we're actually quite primitive.

833
00:40:42,040 --> 00:40:45,040
Speaker 2: The complexity here on Earth is where in the backwater,

834
00:40:45,160 --> 00:40:47,759
Speaker 2: I mean compared to Mars. Sure, but like you were

835
00:40:47,800 --> 00:40:50,359
Speaker 2: saying that, you know, what we've achieved here on Earth

836
00:40:50,440 --> 00:40:53,440
Speaker 2: or what's happened here on Earth is unusually complex. But

837
00:40:53,480 --> 00:40:54,200
Speaker 2: how do we know that?

838
00:40:54,520 --> 00:40:55,640
Speaker 5: Oh, where's the prior?

839
00:40:55,760 --> 00:40:58,320
Speaker 6: I see, So I was referencing that with respect to

840
00:40:58,360 --> 00:41:02,359
Speaker 6: an abiotic prior. Imagine you don't have an evolutionary system, right,

841
00:41:02,400 --> 00:41:04,479
Speaker 6: So I think we're talking cross purposes about the question,

842
00:41:04,600 --> 00:41:06,120
Speaker 6: So I just want to kind of frame it precisely.

843
00:41:06,200 --> 00:41:08,640
Speaker 6: So if you just look at, you know, a system

844
00:41:08,680 --> 00:41:13,680
Speaker 6: that doesn't have evolutionary selection, the sort of framing that

845
00:41:13,719 --> 00:41:17,040
Speaker 6: we have the key conjectures, there's a maximum complexity a

846
00:41:17,080 --> 00:41:19,080
Speaker 6: non living system could build, and it can't build any

847
00:41:19,120 --> 00:41:21,640
Speaker 6: more than that until selection and sort of feedback on

848
00:41:21,680 --> 00:41:24,440
Speaker 6: the structure and like self reproducing systems emerge that actually

849
00:41:24,480 --> 00:41:25,480
Speaker 6: constrain themselves to.

850
00:41:25,480 --> 00:41:26,880
Speaker 5: Be able to perpetuate.

851
00:41:26,960 --> 00:41:30,960
Speaker 6: Right, what you're asking is, if that process starts, are

852
00:41:31,000 --> 00:41:34,120
Speaker 6: we more or less complex than that typical process? And

853
00:41:34,160 --> 00:41:36,719
Speaker 6: I think we don't know the answer to that obviously,

854
00:41:36,840 --> 00:41:40,560
Speaker 6: but I think what I can say is from the

855
00:41:41,160 --> 00:41:45,560
Speaker 6: sort of structure of the physical laws in the theory

856
00:41:45,600 --> 00:41:51,319
Speaker 6: that we're building and testing, every evolutionary system will have

857
00:41:51,400 --> 00:41:52,719
Speaker 6: to climb.

858
00:41:52,360 --> 00:41:53,520
Speaker 5: The ladder of complexity.

859
00:41:54,400 --> 00:41:56,600
Speaker 6: So there is no like major jump where you just

860
00:41:56,640 --> 00:41:58,080
Speaker 6: get to be like the most complex thing in the

861
00:41:58,160 --> 00:42:01,759
Speaker 6: universe by skipping steps. So that a question of did

862
00:42:01,800 --> 00:42:04,760
Speaker 6: life start in the universe on any planets much before

863
00:42:04,840 --> 00:42:08,839
Speaker 6: us or have an accelerated process moving through the sort

864
00:42:08,880 --> 00:42:12,360
Speaker 6: of complexity cascade. And I don't think anyone knows the

865
00:42:12,360 --> 00:42:14,719
Speaker 6: answer to that question. That's one of the reasons that

866
00:42:14,800 --> 00:42:17,240
Speaker 6: we want to understand this physics so we can actually

867
00:42:17,280 --> 00:42:19,960
Speaker 6: make predictions about what that process looks like on other planets.

868
00:42:20,800 --> 00:42:23,279
Speaker 6: And I think we're at this stage where I'm hopeful,

869
00:42:23,680 --> 00:42:25,880
Speaker 6: you know, in the next I don't know, ten years,

870
00:42:25,880 --> 00:42:27,879
Speaker 6: maybe we might be able to say something meaningful about

871
00:42:27,880 --> 00:42:31,200
Speaker 6: the first steps from geochemistry using this kind of theoretical construction,

872
00:42:31,719 --> 00:42:33,560
Speaker 6: like these kind of steps about like what are the

873
00:42:33,560 --> 00:42:36,000
Speaker 6: first mechanisms of selection that emerge in chemistry and what

874
00:42:36,080 --> 00:42:38,719
Speaker 6: do they look like in different planetary context But saying

875
00:42:38,719 --> 00:42:41,839
Speaker 6: something about that whole cascade is basically simulating the entire

876
00:42:41,920 --> 00:42:46,240
Speaker 6: evolutionary process, you know, from the geochemical original life into

877
00:42:46,920 --> 00:42:48,680
Speaker 6: technology on another planet.

878
00:42:48,680 --> 00:42:50,800
Speaker 5: And I don't think that's actually computationally feasible.

879
00:42:50,800 --> 00:42:52,560
Speaker 6: I think we have to discover other life to answer

880
00:42:52,560 --> 00:42:55,000
Speaker 6: that question, which is why we need a theory to

881
00:42:55,000 --> 00:42:55,799
Speaker 6: know what we're looking for.

882
00:42:56,160 --> 00:42:59,960
Speaker 1: So would geologists come across molecules that look complicated or

883
00:43:00,400 --> 00:43:03,200
Speaker 1: chemistry was the class I did not get as in, yeah,

884
00:43:03,000 --> 00:43:04,840
Speaker 1: so how do you know that you've got like a

885
00:43:04,880 --> 00:43:08,200
Speaker 1: complicated molecule that's life or do you get similarly complicated

886
00:43:08,200 --> 00:43:10,720
Speaker 1: molecules in the geology lab that are not alive.

887
00:43:10,960 --> 00:43:14,520
Speaker 6: It's a non trivial question, highly non trivial, and I

888
00:43:14,520 --> 00:43:16,840
Speaker 6: think part of it comes from the different uses of

889
00:43:16,880 --> 00:43:19,799
Speaker 6: the word complexity. So I think a lot of my

890
00:43:19,880 --> 00:43:22,840
Speaker 6: planetary science colleagues and geologists would say, of course we

891
00:43:22,880 --> 00:43:26,000
Speaker 6: find complexity in chemical systems, we see it all the time.

892
00:43:26,400 --> 00:43:28,719
Speaker 6: The kind of complexity that they're talking about is often

893
00:43:28,760 --> 00:43:31,560
Speaker 6: what we see in prevotic chemistry experiments also, which is

894
00:43:32,360 --> 00:43:35,840
Speaker 6: oftentimes like the most problematic thing you see in prevatic chemistries.

895
00:43:35,840 --> 00:43:38,400
Speaker 6: If you just run an unconstrained reaction, you get what

896
00:43:38,440 --> 00:43:41,359
Speaker 6: we call a tar, which is a non differentiated mess

897
00:43:41,360 --> 00:43:45,400
Speaker 6: of molecules. So these kind of systems can generate a

898
00:43:45,480 --> 00:43:48,680
Speaker 6: lot of molecular diversity, but it tends to be things

899
00:43:49,200 --> 00:43:53,279
Speaker 6: that would be low complexity as individual molecules, and for

900
00:43:53,360 --> 00:43:55,279
Speaker 6: things that are higher complexity, you don't see a lot

901
00:43:55,280 --> 00:43:58,680
Speaker 6: of them. And that's very different than what we see

902
00:43:58,719 --> 00:44:01,360
Speaker 6: in life, which is we see, you know, there's a

903
00:44:01,360 --> 00:44:03,719
Speaker 6: lot of diversity molecules in life, but compared to the

904
00:44:03,760 --> 00:44:06,360
Speaker 6: size of the chemical space that that could be you know,

905
00:44:06,440 --> 00:44:10,719
Speaker 6: equivalent structure or like molecular weight or you know, number

906
00:44:10,719 --> 00:44:13,400
Speaker 6: of chiral centers, or you know number of elements in

907
00:44:13,440 --> 00:44:15,520
Speaker 6: the molecule, like any of these features you might say

908
00:44:15,600 --> 00:44:19,520
Speaker 6: is equivalent molecules. You see very very very very low

909
00:44:19,560 --> 00:44:23,200
Speaker 6: diversity in biology. And so what biology does is it

910
00:44:23,239 --> 00:44:26,920
Speaker 6: builds molecules that are deep in the space of chemistry,

911
00:44:26,960 --> 00:44:28,640
Speaker 6: like they require a lot of parts to build the

912
00:44:28,719 --> 00:44:33,200
Speaker 6: specific molecule. So that molecule is complex in an evolutionary sense.

913
00:44:33,800 --> 00:44:36,640
Speaker 6: It's found in high abundance, but there's not a huge

914
00:44:36,640 --> 00:44:39,320
Speaker 6: diversity of exploring in an unconstrained way the space of

915
00:44:39,360 --> 00:44:43,440
Speaker 6: all molecules. So I think the kind of complexity we

916
00:44:43,480 --> 00:44:47,319
Speaker 6: talk about in a planetary science sense doesn't discover the

917
00:44:47,400 --> 00:44:49,240
Speaker 6: kind of complexity that biology generates.

918
00:44:49,760 --> 00:44:52,000
Speaker 2: So let's dig into that a little bit, because I

919
00:44:52,040 --> 00:44:54,520
Speaker 2: think that's really at the core of the argument in

920
00:44:54,520 --> 00:44:58,000
Speaker 2: your book, right, this concept of complexity and how we

921
00:44:58,080 --> 00:45:00,840
Speaker 2: discover it and what it means for life to be complex.

922
00:45:01,280 --> 00:45:04,680
Speaker 2: So you're saying that life is something that uses a

923
00:45:04,760 --> 00:45:08,520
Speaker 2: relatively small number of building blocks but puts them together

924
00:45:09,239 --> 00:45:12,359
Speaker 2: in a way that's very complex. Right. The complexity comes

925
00:45:12,400 --> 00:45:14,960
Speaker 2: from the arrangements of a few bits, not from the

926
00:45:15,239 --> 00:45:19,760
Speaker 2: inherent complexity of the pieces and that of the chemical

927
00:45:19,840 --> 00:45:22,560
Speaker 2: space that exists out there. As you're saying earlier, it

928
00:45:22,640 --> 00:45:25,799
Speaker 2: uses a tiny, little, very tiny, yeah, very tiny little

929
00:45:25,800 --> 00:45:29,960
Speaker 2: aspect of that. And so again I wonder like, how

930
00:45:29,960 --> 00:45:32,760
Speaker 2: do we know how unusual that is, or how special

931
00:45:32,880 --> 00:45:34,840
Speaker 2: that is, how distinct that is? How do we know

932
00:45:34,880 --> 00:45:39,200
Speaker 2: that it's not possible using other building blocks to create complexity?

933
00:45:39,239 --> 00:45:42,520
Speaker 2: How do we know that complexity doesn't always arise if

934
00:45:42,520 --> 00:45:44,120
Speaker 2: you start from you know, basic bits.

935
00:45:44,600 --> 00:45:47,320
Speaker 6: Yeah, this is the more exciting question, and it's actually

936
00:45:47,560 --> 00:45:50,239
Speaker 6: you know, the one Experimentally, I'm really interested in if

937
00:45:50,280 --> 00:45:53,880
Speaker 6: you designed an original life experiment that was modeling a

938
00:45:53,920 --> 00:45:59,080
Speaker 6: planetary environment and it was unconstrained and selection and evolutionary

939
00:45:59,120 --> 00:46:02,120
Speaker 6: processes emerging, which in the system just by the dynamics

940
00:46:02,160 --> 00:46:05,800
Speaker 6: of the chemistry, would it discover the same biochemistry?

941
00:46:06,200 --> 00:46:08,560
Speaker 5: And I'm not convinced it would. I think chemical space

942
00:46:08,640 --> 00:46:10,280
Speaker 5: is so large that there are a lot.

943
00:46:10,120 --> 00:46:13,840
Speaker 6: Of potential chemical architectures for life that could be quite different,

944
00:46:14,840 --> 00:46:18,680
Speaker 6: but we haven't discovered them yet. Because life on Earth,

945
00:46:19,280 --> 00:46:23,560
Speaker 6: you know, had one solution that allowed it to perpetuate

946
00:46:23,640 --> 00:46:26,680
Speaker 6: itself and had to use that architecture for billions of years.

947
00:46:26,840 --> 00:46:29,279
Speaker 6: And you know, the question is if the original life

948
00:46:29,280 --> 00:46:31,360
Speaker 6: happened again, would it discover the same architecture or not?

949
00:46:31,800 --> 00:46:33,040
Speaker 5: And nobody knows the answer to that.

950
00:46:33,280 --> 00:46:36,680
Speaker 6: I think that's an experimental question, you know, and that's

951
00:46:36,719 --> 00:46:38,799
Speaker 6: one that we want to ask because you know, part

952
00:46:38,840 --> 00:46:41,080
Speaker 6: of the thing I you know, try to really highlight

953
00:46:41,600 --> 00:46:43,399
Speaker 6: in the discussion in the book, but I'm also really

954
00:46:43,400 --> 00:46:46,080
Speaker 6: trying to just pitch to people as an experimental program

955
00:46:46,080 --> 00:46:47,759
Speaker 6: that we need to do because it requires a lot

956
00:46:47,800 --> 00:46:51,240
Speaker 6: of investment of technology and resources, is to think through

957
00:46:51,400 --> 00:46:53,920
Speaker 6: how we would build an experimental program to discover alien

958
00:46:53,960 --> 00:46:56,880
Speaker 6: life in the lab and the idea of there exactly

959
00:46:57,800 --> 00:47:00,919
Speaker 6: in the lab. Yes, it's exactly what you're saying though,

960
00:47:00,920 --> 00:47:03,600
Speaker 6: like we don't know if life could exist in other chemistries.

961
00:47:03,960 --> 00:47:06,759
Speaker 6: If you do a proper original life experiment and you

962
00:47:06,840 --> 00:47:09,480
Speaker 6: really want to know the spontaneous probability for a universe

963
00:47:09,520 --> 00:47:12,120
Speaker 6: to generate life, you can't just cherry pick and use

964
00:47:12,120 --> 00:47:13,960
Speaker 6: them like our structures that were selected on Earth and

965
00:47:13,960 --> 00:47:16,120
Speaker 6: say I'm going to make these because you're inducing selection

966
00:47:16,840 --> 00:47:20,240
Speaker 6: based on what was produced on Earth right prior knowledge

967
00:47:20,280 --> 00:47:22,440
Speaker 6: of it. You really want to see from chemistry, what

968
00:47:22,480 --> 00:47:27,480
Speaker 6: would it generate without any intervention from us, as you know,

969
00:47:28,120 --> 00:47:30,960
Speaker 6: designers of the chemistry, knowing what we know of Earth life.

970
00:47:31,280 --> 00:47:34,120
Speaker 6: So I think the original life problem is actually that's

971
00:47:34,160 --> 00:47:38,560
Speaker 6: exactly what it is, is an experimental problem to try

972
00:47:38,600 --> 00:47:43,800
Speaker 6: to discover what is the mechanism chemistry generates living forms.

973
00:47:44,120 --> 00:47:47,359
Speaker 6: And if you know that mechanism, is it universally going

974
00:47:47,400 --> 00:47:49,040
Speaker 6: to converge on what life on Earth did?

975
00:47:49,120 --> 00:47:51,640
Speaker 5: Or are there many solutions? Because this space is so huge.

976
00:47:52,080 --> 00:47:54,280
Speaker 1: I'm sure you could get a lot of evolutionary biologies

977
00:47:54,400 --> 00:47:57,600
Speaker 1: very excited if you could repeatedly generate them.

978
00:47:57,719 --> 00:47:59,239
Speaker 5: You need their talent, so that's good.

979
00:48:00,840 --> 00:48:03,640
Speaker 6: Yeah, I think you know, part of my motivation with right,

980
00:48:03,920 --> 00:48:07,120
Speaker 6: it's hard to write a book, right, And for first

981
00:48:07,120 --> 00:48:09,120
Speaker 6: and foremost I'm about the science, Like I just really

982
00:48:09,120 --> 00:48:10,560
Speaker 6: want to solve the original life. So part of my

983
00:48:10,600 --> 00:48:13,000
Speaker 6: motivation is to get people excited about like what are the.

984
00:48:12,960 --> 00:48:14,480
Speaker 5: Actual critical challenges here?

985
00:48:14,560 --> 00:48:16,960
Speaker 6: And I think I think this one is like the

986
00:48:17,000 --> 00:48:19,520
Speaker 6: main one is like what does the experimental program look

987
00:48:19,600 --> 00:48:22,239
Speaker 6: like that solves the original life? And how related is

988
00:48:22,280 --> 00:48:24,240
Speaker 6: it to all these other questions that we're talking about,

989
00:48:24,280 --> 00:48:27,040
Speaker 6: And for me, it is going to require you know,

990
00:48:27,200 --> 00:48:32,240
Speaker 6: really intense technological infrastructure, building digital chemistry and AI driven

991
00:48:32,360 --> 00:48:35,800
Speaker 6: robotic chemistry to actually search chemical space like a search engine,

992
00:48:36,160 --> 00:48:38,719
Speaker 6: and then looking for these kind of chemistries and when

993
00:48:38,719 --> 00:48:41,400
Speaker 6: they undergo selection and they start emerging things that we

994
00:48:41,520 --> 00:48:44,319
Speaker 6: might call life. And the reason for having to build

995
00:48:44,320 --> 00:48:47,160
Speaker 6: a theory in part besides all the reasons I have

996
00:48:47,200 --> 00:48:50,120
Speaker 6: as a physicist, is if the chemistry is radically different,

997
00:48:50,160 --> 00:48:52,040
Speaker 6: how do you even know it's a living thing. And

998
00:48:52,120 --> 00:48:54,239
Speaker 6: so we have to be able to measure evolution in

999
00:48:54,360 --> 00:48:59,399
Speaker 6: molecules agnostic to what molecules evolution creates, and know that

1000
00:48:59,480 --> 00:49:04,439
Speaker 6: they have of a comparable level of selection in them

1001
00:49:04,520 --> 00:49:06,920
Speaker 6: to say that, you know, this is past the threshold

1002
00:49:06,920 --> 00:49:09,080
Speaker 6: that we expect it to be a living form versus

1003
00:49:10,120 --> 00:49:12,879
Speaker 6: you know what we expect a biogs systems that aren't

1004
00:49:12,920 --> 00:49:14,560
Speaker 6: evolving to be able to generate.

1005
00:49:14,920 --> 00:49:16,600
Speaker 2: And so this is sort of the core argument of

1006
00:49:16,600 --> 00:49:20,239
Speaker 2: your book. You describe assembly theory, where you measure the

1007
00:49:20,280 --> 00:49:23,520
Speaker 2: complexity of something as the number of steps it takes

1008
00:49:23,600 --> 00:49:25,600
Speaker 2: essentially to build some of the shortest path to go

1009
00:49:25,760 --> 00:49:29,439
Speaker 2: from building blocks to this thing. Right, and then you

1010
00:49:29,920 --> 00:49:32,280
Speaker 2: do this thing where you say, well, anything above fifteen

1011
00:49:32,320 --> 00:49:35,800
Speaker 2: steps is life, and anything below fifteen steps is not life.

1012
00:49:36,320 --> 00:49:38,640
Speaker 2: And I was with you until I got to that point.

1013
00:49:38,719 --> 00:49:41,319
Speaker 2: I found myself asking, as you actually did in the book, like, well,

1014
00:49:41,360 --> 00:49:45,960
Speaker 2: why fifteen doesn't it feel sort of arbitrary? How do

1015
00:49:46,000 --> 00:49:46,840
Speaker 2: we know it's fifteen?

1016
00:49:46,880 --> 00:49:49,759
Speaker 5: It's like it should be forty two, right, forty two

1017
00:49:49,760 --> 00:49:50,479
Speaker 5: would have been better?

1018
00:49:50,600 --> 00:49:53,040
Speaker 2: Yeah, give is a description of that thought process.

1019
00:49:53,200 --> 00:49:54,080
Speaker 5: No, it's a good question.

1020
00:49:54,200 --> 00:49:57,439
Speaker 6: So fifteen is maybe an approximate bound, right, But where

1021
00:49:57,480 --> 00:50:00,279
Speaker 6: that comes from is actually the experimental data. It's not

1022
00:50:00,400 --> 00:50:03,279
Speaker 6: like anointed you know, like the assembly theory cult said

1023
00:50:03,280 --> 00:50:04,240
Speaker 6: it's going to be fifteen.

1024
00:50:04,320 --> 00:50:07,200
Speaker 5: It's just like, you know, we build cult.

1025
00:50:07,400 --> 00:50:10,480
Speaker 6: I know, right, and there is no cult actually, Like

1026
00:50:10,520 --> 00:50:13,080
Speaker 6: it's really funny because you know, there's a lot of

1027
00:50:13,160 --> 00:50:15,880
Speaker 6: challenges we're getting developing this theory from people picking it

1028
00:50:15,920 --> 00:50:17,120
Speaker 6: apart different ways, which we love.

1029
00:50:17,160 --> 00:50:18,880
Speaker 5: But I don't think anyone's harder on it than the

1030
00:50:18,880 --> 00:50:21,120
Speaker 5: people we have actually working on it. So it's like,

1031
00:50:21,640 --> 00:50:22,840
Speaker 5: which is the best kind of science?

1032
00:50:22,920 --> 00:50:24,520
Speaker 6: Right, Like you pick apart every idea and you re

1033
00:50:24,600 --> 00:50:26,520
Speaker 6: evaluate everything you're doing at every step.

1034
00:50:26,560 --> 00:50:28,520
Speaker 2: Well, if you're denying the existence of the cult, that

1035
00:50:28,560 --> 00:50:30,240
Speaker 2: tells me that the cult definitely exists.

1036
00:50:30,280 --> 00:50:32,440
Speaker 5: Oh sure, yeah, I know, right, you're just I'm going

1037
00:50:32,480 --> 00:50:33,160
Speaker 5: to wink wink.

1038
00:50:33,120 --> 00:50:37,439
Speaker 2: Wink, tell us about the data that supports the choices.

1039
00:50:37,600 --> 00:50:39,520
Speaker 5: Yeah, so that comes from the data.

1040
00:50:39,560 --> 00:50:43,280
Speaker 6: So this idea of this minimal pass so involves you recursions.

1041
00:50:43,320 --> 00:50:46,320
Speaker 6: So the idea is like, it's easier with lego than chemistry,

1042
00:50:46,640 --> 00:50:48,200
Speaker 6: you know, because most of us aren't chemists. So it's like,

1043
00:50:48,239 --> 00:50:51,759
Speaker 6: you think you're building a particular lego structure. I usually

1044
00:50:51,800 --> 00:50:53,600
Speaker 6: use Howkwarts castle as people know, but like the taj

1045
00:50:53,640 --> 00:50:56,320
Speaker 6: Ma hall or whatever, you know, building you might prefer,

1046
00:50:56,960 --> 00:50:59,320
Speaker 6: you know, you wouldn't expect to form it by randomly

1047
00:50:59,320 --> 00:51:01,680
Speaker 6: shaking the building blocks in the box. Right, there's instructions

1048
00:51:01,719 --> 00:51:04,200
Speaker 6: that allow you to make it. In assembly theory, you

1049
00:51:04,280 --> 00:51:06,400
Speaker 6: realize if you take the instructions, there's actually lots of

1050
00:51:06,400 --> 00:51:08,520
Speaker 6: different ways of getting to the end root if you

1051
00:51:08,560 --> 00:51:10,920
Speaker 6: don't use the instructions. Right, So in assembly theory, we

1052
00:51:11,000 --> 00:51:14,160
Speaker 6: have to ground it in something that's always there about

1053
00:51:14,160 --> 00:51:16,960
Speaker 6: that structure, and not just because you had a particular

1054
00:51:17,040 --> 00:51:19,359
Speaker 6: set of instructions in a particular environment to make that.

1055
00:51:20,000 --> 00:51:22,439
Speaker 6: And so we do this based on this minimal path

1056
00:51:22,480 --> 00:51:25,400
Speaker 6: idea and the assumptions of the minimal path are you

1057
00:51:25,440 --> 00:51:27,839
Speaker 6: can only build things if you already build them, and

1058
00:51:27,880 --> 00:51:29,800
Speaker 6: you want to try to find the shortest path where

1059
00:51:29,840 --> 00:51:32,680
Speaker 6: you're reusing parts you've built already to build the final structure,

1060
00:51:32,800 --> 00:51:36,279
Speaker 6: so very minimal set of assumptions. It turns out that

1061
00:51:36,320 --> 00:51:39,920
Speaker 6: feature you can actually measure in the lab, and we

1062
00:51:40,000 --> 00:51:42,080
Speaker 6: measured it in the paper that we tried to do

1063
00:51:42,440 --> 00:51:45,840
Speaker 6: biosignature of validation in using mass spectrometry, but there was

1064
00:51:45,840 --> 00:51:48,440
Speaker 6: a later paper from Leekronin's group that came out showing

1065
00:51:48,520 --> 00:51:51,480
Speaker 6: that you can also measure assembly index this shortest path

1066
00:51:51,520 --> 00:51:53,000
Speaker 6: measure with NMR and infrared.

1067
00:51:53,360 --> 00:51:55,279
Speaker 5: So we have a strong sort of.

1068
00:51:55,280 --> 00:51:58,520
Speaker 6: Conviction right now as a running assumption with the theory

1069
00:51:58,520 --> 00:52:01,359
Speaker 6: that it's an intrinsic property a molecule. This feature, it's

1070
00:52:01,360 --> 00:52:04,719
Speaker 6: one that you can measure with independent measuring apparatus. It

1071
00:52:04,719 --> 00:52:07,200
Speaker 6: doesn't depend on where the environment where the molecule was made,

1072
00:52:07,640 --> 00:52:10,239
Speaker 6: So that gives us some of the baseline criteria of

1073
00:52:10,280 --> 00:52:12,800
Speaker 6: something being an objective measure of the amount of selection

1074
00:52:13,680 --> 00:52:15,480
Speaker 6: in an object, and then what you have in a

1075
00:52:15,560 --> 00:52:18,240
Speaker 6: molecule that you can go and measure in the labs.

1076
00:52:18,360 --> 00:52:20,960
Speaker 6: So you know, if I went to Enceladus and I

1077
00:52:21,040 --> 00:52:23,000
Speaker 6: measured it, you know, the molecule would have the same

1078
00:52:23,080 --> 00:52:26,680
Speaker 6: value it would have on Earth. Okay, so that's important.

1079
00:52:26,719 --> 00:52:28,880
Speaker 6: And so the question is then if you use that,

1080
00:52:29,800 --> 00:52:33,640
Speaker 6: does it actually separate out things that are uniquely produced

1081
00:52:33,640 --> 00:52:37,040
Speaker 6: by life from not And so to do this, Lee's

1082
00:52:37,080 --> 00:52:41,560
Speaker 6: lab took a bunch of samples, you know, abiotic and biotic,

1083
00:52:42,200 --> 00:52:45,160
Speaker 6: even some Scotch whiskey, and then they had some samples

1084
00:52:45,200 --> 00:52:48,480
Speaker 6: that were blinded from NASA that were both biological and

1085
00:52:48,480 --> 00:52:51,440
Speaker 6: non biological, sort of an adversarial test case. And what

1086
00:52:51,480 --> 00:52:54,120
Speaker 6: they did is they use this mass spec method to

1087
00:52:54,160 --> 00:52:57,440
Speaker 6: measure assembly index on the actual samples, and they showed

1088
00:52:57,480 --> 00:53:01,759
Speaker 6: that using assembly theory bind with the mass spect data,

1089
00:53:01,960 --> 00:53:08,840
Speaker 6: they only saw molecules that were more than fifteen steps

1090
00:53:08,880 --> 00:53:13,120
Speaker 6: in this minimal path being produced by living samples. And

1091
00:53:13,360 --> 00:53:16,319
Speaker 6: this gets to the complicated versus complexity issue because one

1092
00:53:16,360 --> 00:53:20,560
Speaker 6: of the adversarial samples that NASA cent was actually Murchison meteorite,

1093
00:53:21,000 --> 00:53:24,160
Speaker 6: which oftentimes in prebatic chemistry literature you will see as

1094
00:53:24,200 --> 00:53:27,600
Speaker 6: being like the most complex sample of prebatic chemistry, and

1095
00:53:27,760 --> 00:53:31,760
Speaker 6: it was still below fifteen for the molecules in the sample.

1096
00:53:32,640 --> 00:53:34,439
Speaker 6: So what you see in Merchison is again this tar

1097
00:53:34,560 --> 00:53:36,520
Speaker 6: You have a lot of molecules, but none of them

1098
00:53:36,520 --> 00:53:40,839
Speaker 6: are high abundance and a high assembly. And so it's

1099
00:53:40,880 --> 00:53:43,399
Speaker 6: not just that the molecule is high assembly. You actually

1100
00:53:43,480 --> 00:53:47,440
Speaker 6: have to have it in a high enough abundance to

1101
00:53:47,480 --> 00:53:50,839
Speaker 6: say that it was selected in that particular context.

1102
00:53:50,880 --> 00:53:53,479
Speaker 2: Right, So, but does that mean that if I find

1103
00:53:53,520 --> 00:53:56,520
Speaker 2: some sample on an alien planet and you measure its

1104
00:53:56,560 --> 00:53:59,160
Speaker 2: assembly index and it comes out to forty two, You're

1105
00:53:59,160 --> 00:54:01,680
Speaker 2: going to be like this life? Are you proposing this

1106
00:54:01,719 --> 00:54:04,960
Speaker 2: as a definition of life? A discrow way to decide?

1107
00:54:05,480 --> 00:54:08,120
Speaker 6: I think that would be the ultimate outcome based on

1108
00:54:08,160 --> 00:54:09,680
Speaker 6: the path that we're on, but I think we have

1109
00:54:09,719 --> 00:54:12,359
Speaker 6: a lot more work to do to be like definitively

1110
00:54:12,440 --> 00:54:15,520
Speaker 6: there is a threshold and assembly spaces above which you

1111
00:54:15,600 --> 00:54:19,120
Speaker 6: would say that a sample was life or not. And

1112
00:54:19,160 --> 00:54:20,800
Speaker 6: that's sort of where we're going. So right now, I

1113
00:54:20,800 --> 00:54:23,080
Speaker 6: would be pretty high confident if you discovered something on

1114
00:54:23,239 --> 00:54:26,120
Speaker 6: Enceladus that was forty two that.

1115
00:54:26,120 --> 00:54:27,760
Speaker 5: It could only be produced by life.

1116
00:54:28,600 --> 00:54:32,560
Speaker 6: But the sort of next steps are really actually theoretically

1117
00:54:32,600 --> 00:54:35,360
Speaker 6: predicting why it should be the number fifteen and what

1118
00:54:35,560 --> 00:54:37,480
Speaker 6: number it should be. If you have variations in your

1119
00:54:37,520 --> 00:54:40,040
Speaker 6: elemental distributions or other things about the structure of the

1120
00:54:40,080 --> 00:54:43,000
Speaker 6: assembly space, which is the underlying mathematical structure that we

1121
00:54:43,080 --> 00:54:45,880
Speaker 6: build this whole formalism out of. And so one of

1122
00:54:45,920 --> 00:54:48,040
Speaker 6: the projects in my lab right now is actually trying

1123
00:54:48,080 --> 00:54:52,440
Speaker 6: to quantify why there's a transition in assembly theory at

1124
00:54:52,440 --> 00:54:55,239
Speaker 6: the particular assembly index values that we see and might

1125
00:54:55,280 --> 00:54:56,840
Speaker 6: see in different systems.

1126
00:54:56,600 --> 00:54:59,120
Speaker 2: Because, as you say, the chemical space is very large.

1127
00:54:59,680 --> 00:55:04,000
Speaker 2: Is this structures out there that are quite complex but

1128
00:55:04,040 --> 00:55:05,960
Speaker 2: that nobody would call alive.

1129
00:55:05,920 --> 00:55:09,279
Speaker 6: Right, So there are many such structures, right, So it's

1130
00:55:09,320 --> 00:55:12,279
Speaker 6: not necessarily that the threshold must be at fifteen. That's

1131
00:55:12,360 --> 00:55:15,239
Speaker 6: where we have for the kinds of chemistry that we

1132
00:55:15,280 --> 00:55:18,239
Speaker 6: test in the lab so far. When we have a

1133
00:55:18,280 --> 00:55:22,520
Speaker 6: general theory, which we're working on very fervently right now

1134
00:55:22,520 --> 00:55:25,160
Speaker 6: with our teams, we would be able to predict, based

1135
00:55:25,200 --> 00:55:28,160
Speaker 6: on the sort of elemental composition and other features of

1136
00:55:28,160 --> 00:55:30,799
Speaker 6: your chemistry, where that threshold should be. And then that

1137
00:55:30,840 --> 00:55:33,120
Speaker 6: allows us further tests to really validate that this works

1138
00:55:33,120 --> 00:55:35,759
Speaker 6: in different systems. And you know, one place where it

1139
00:55:35,840 --> 00:55:38,200
Speaker 6: might be more challenging is actually with minerals, because minerals

1140
00:55:38,239 --> 00:55:41,560
Speaker 6: don't uphold all of the properties of molecules. They have

1141
00:55:41,719 --> 00:55:44,360
Speaker 6: very different structure, but they're also made out of elements

1142
00:55:44,400 --> 00:55:48,120
Speaker 6: bonding and minerals because they have very different structure to

1143
00:55:48,200 --> 00:55:49,960
Speaker 6: how you build up a mineral in this kind of

1144
00:55:50,160 --> 00:55:53,359
Speaker 6: way that we do, this kind of recursive construction, and

1145
00:55:53,440 --> 00:55:55,520
Speaker 6: what you would define as a repeat in a mineral.

1146
00:55:55,920 --> 00:55:58,359
Speaker 6: They might have a you know, a threshold that's much

1147
00:55:58,400 --> 00:56:01,040
Speaker 6: higher than what we observe for aqueous like our chemistry.

1148
00:56:01,480 --> 00:56:04,680
Speaker 6: And so, as with any new theory of physics, it's

1149
00:56:04,680 --> 00:56:08,120
Speaker 6: a process of suggesting an idea, testing it, iterating on

1150
00:56:08,160 --> 00:56:10,120
Speaker 6: the idea, and so you know, the process of theory

1151
00:56:10,160 --> 00:56:13,680
Speaker 6: building doesn't happen overnight. It happens over a decade or two.

1152
00:56:13,760 --> 00:56:15,920
Speaker 6: And so these are some of the frontier questions that

1153
00:56:15,920 --> 00:56:18,200
Speaker 6: we're asking about, Like, you know, is this actually, you know,

1154
00:56:18,280 --> 00:56:21,319
Speaker 6: the right approach, then these things should work out, but

1155
00:56:21,440 --> 00:56:22,439
Speaker 6: we don't know the answer yet.

1156
00:56:22,480 --> 00:56:23,480
Speaker 5: So that's why it's exciting.

1157
00:56:24,200 --> 00:56:28,960
Speaker 1: Sometimes life gets overwhelming, and sometimes conversations about life get overwhelming.

1158
00:56:29,040 --> 00:56:31,000
Speaker 1: So I feel like it's time for a break. So

1159
00:56:31,200 --> 00:56:36,239
Speaker 1: let's go ahead and hear a word from our sponsors.

1160
00:56:46,680 --> 00:56:48,920
Speaker 2: I hope your brains are arrested and ready for some

1161
00:56:49,000 --> 00:56:54,280
Speaker 2: more overwhelming conversation about incredible topics like the physics of life.

1162
00:56:55,280 --> 00:56:57,759
Speaker 2: It is exciting. One question I would have in my

1163
00:56:57,840 --> 00:56:59,840
Speaker 2: mind if I was working on this is like, whether

1164
00:57:00,160 --> 00:57:02,640
Speaker 2: value is fifteen or nineteen or fourteen or whatever, how

1165
00:57:02,680 --> 00:57:04,920
Speaker 2: do we know that all the information is captured by

1166
00:57:05,040 --> 00:57:08,560
Speaker 2: this one quantity? You back it up so far with like, well,

1167
00:57:08,600 --> 00:57:10,400
Speaker 2: we have a bunch of these examples and it seems

1168
00:57:10,400 --> 00:57:13,279
Speaker 2: to have worked. And you're working on the theoretical underpinnings,

1169
00:57:13,760 --> 00:57:16,280
Speaker 2: you know. I work on machine learning problems all the

1170
00:57:16,320 --> 00:57:18,920
Speaker 2: time where we convince ourselves we've learned how to distinguish

1171
00:57:19,000 --> 00:57:21,280
Speaker 2: between A and B because we've only seen some kind

1172
00:57:21,320 --> 00:57:23,080
Speaker 2: of examples, and then we go off into the world

1173
00:57:23,080 --> 00:57:25,960
Speaker 2: we're like, oops, turns out that's just one dimension of

1174
00:57:26,000 --> 00:57:30,080
Speaker 2: a multi dimensional problem. You know. For example, if I was,

1175
00:57:30,640 --> 00:57:33,000
Speaker 2: you know, not intelligent about this, and I said, well, look,

1176
00:57:33,040 --> 00:57:34,800
Speaker 2: I took a bunch of examples of living things that

1177
00:57:34,880 --> 00:57:37,520
Speaker 2: all have brown hair and non living things that don't

1178
00:57:37,560 --> 00:57:39,880
Speaker 2: have brown hair, and then I developed my definition of

1179
00:57:39,920 --> 00:57:42,480
Speaker 2: life to be like, does it have brown hair? I

1180
00:57:42,520 --> 00:57:45,240
Speaker 2: could also come up with a way to distinguish between

1181
00:57:45,320 --> 00:57:48,680
Speaker 2: quote unquote living and unliving things because my sample was

1182
00:57:48,720 --> 00:57:51,680
Speaker 2: limited and here your sample is limited because you only

1183
00:57:51,720 --> 00:57:55,280
Speaker 2: have examples from you know, life we've seen, and so

1184
00:57:55,320 --> 00:57:57,680
Speaker 2: how do I know that there is a number that distinguishes.

1185
00:57:58,240 --> 00:58:01,240
Speaker 6: So there's a couple of things, and there one of

1186
00:58:01,280 --> 00:58:03,400
Speaker 6: them is assembly theory is not a scaler theory. So

1187
00:58:03,440 --> 00:58:05,680
Speaker 6: it's not just about this number. It's actually about also

1188
00:58:05,760 --> 00:58:08,120
Speaker 6: the abundance of objects at different assembly and deses.

1189
00:58:08,160 --> 00:58:10,040
Speaker 5: So it's higher dimensional than that.

1190
00:58:10,200 --> 00:58:13,440
Speaker 6: And the idea is you're talking about selection in this

1191
00:58:13,560 --> 00:58:16,240
Speaker 6: massive combinatorial space, and you have to talk about the

1192
00:58:16,280 --> 00:58:19,040
Speaker 6: reduction of the size of the space represented in the

1193
00:58:19,080 --> 00:58:22,560
Speaker 6: objects you observe. And we have rigorous ways for thinking,

1194
00:58:23,000 --> 00:58:25,400
Speaker 6: like based on the mathematical formalism of the theory, why

1195
00:58:25,440 --> 00:58:27,840
Speaker 6: we're capturing the relevant features of that reduction of the

1196
00:58:27,840 --> 00:58:31,680
Speaker 6: size of the space. People usually do do exactly what

1197
00:58:31,720 --> 00:58:34,560
Speaker 6: you're saying, where they try to, you know, separate living

1198
00:58:34,640 --> 00:58:36,720
Speaker 6: and non living things and then classify them. And it's

1199
00:58:36,720 --> 00:58:38,800
Speaker 6: becoming very popular in national biology right now to do

1200
00:58:38,840 --> 00:58:41,120
Speaker 6: machine learning on those kind of problems. I don't think

1201
00:58:41,160 --> 00:58:44,200
Speaker 6: that that approach is generalizable. The reason I have confidence

1202
00:58:44,200 --> 00:58:47,280
Speaker 6: in what we're doing is because there's a whole theoretical infrastructure,

1203
00:58:47,720 --> 00:58:50,160
Speaker 6: building in a whole bunch of ideas about the nature

1204
00:58:50,160 --> 00:58:52,800
Speaker 6: of information in life, What is causation in life? How

1205
00:58:52,800 --> 00:58:54,560
Speaker 6: do we measure these features in molecules?

1206
00:58:55,080 --> 00:58:57,640
Speaker 5: You know? What is it about these emergent properties of life?

1207
00:58:57,640 --> 00:58:57,960
Speaker 3: Like I?

1208
00:58:58,000 --> 00:59:00,360
Speaker 6: You know, I've spent my entire career basically working on

1209
00:59:00,400 --> 00:59:03,960
Speaker 6: every kind of biological system imaginable, and Lee's lab has

1210
00:59:03,960 --> 00:59:06,440
Speaker 6: worked on kind of every chemical system imaginable, and putting

1211
00:59:06,440 --> 00:59:09,240
Speaker 6: all of that knowledge into one theoretical structure that we

1212
00:59:09,320 --> 00:59:11,480
Speaker 6: can really stand behind and say, this captures the features

1213
00:59:11,480 --> 00:59:14,320
Speaker 6: we think are important, and we can measure it, and

1214
00:59:14,360 --> 00:59:16,520
Speaker 6: we want to test it by actually building living things

1215
00:59:16,520 --> 00:59:19,760
Speaker 6: in the lab. So it's not ever going to be

1216
00:59:19,800 --> 00:59:22,560
Speaker 6: convinced by just this measure and the copy number. What

1217
00:59:22,600 --> 00:59:26,200
Speaker 6: you get convinced of is an explanatory paradigm that allows

1218
00:59:26,240 --> 00:59:28,320
Speaker 6: you to explain not just this one data set, but

1219
00:59:28,400 --> 00:59:31,320
Speaker 6: a whole bunch of different things. And so ultimately the

1220
00:59:31,360 --> 00:59:32,680
Speaker 6: proof of the theory is going to come from the

1221
00:59:32,720 --> 00:59:36,160
Speaker 6: generalizability and the new questions it allows us to answer,

1222
00:59:36,600 --> 00:59:37,600
Speaker 6: not what we've done so.

1223
00:59:37,640 --> 00:59:41,200
Speaker 5: Far, so't I wouldn't hang my hat on it. The

1224
00:59:41,280 --> 00:59:42,040
Speaker 5: data we have so far.

1225
00:59:42,080 --> 00:59:45,000
Speaker 6: But what I'm hanging my hat on is the potential

1226
00:59:45,000 --> 00:59:47,320
Speaker 6: things that this is opening up and the way it's

1227
00:59:47,360 --> 00:59:49,720
Speaker 6: allowing a unified explanation for a whole bunch of problems

1228
00:59:49,720 --> 00:59:53,640
Speaker 6: in astrobiology that have traditionally been considered completely separate. And

1229
00:59:53,720 --> 00:59:55,840
Speaker 6: also on what we talked about at the very beginning,

1230
00:59:55,880 --> 00:59:59,720
Speaker 6: about what is physics and what does physics do? And

1231
00:59:59,760 --> 01:00:02,160
Speaker 6: for me, it's about the explanation for the nature of

1232
01:00:02,200 --> 01:00:04,440
Speaker 6: life that's more important than anyone experiment.

1233
01:00:04,920 --> 01:00:06,560
Speaker 1: That feels like a nice note to end things on,

1234
01:00:07,040 --> 01:00:09,840
Speaker 1: like a nice wrap up is did you have another question.

1235
01:00:09,640 --> 01:00:13,360
Speaker 2: Daniel, Yeah, I would love to hear, just as a

1236
01:00:13,400 --> 01:00:16,360
Speaker 2: final vision, like how you think this could, in the

1237
01:00:16,360 --> 01:00:19,640
Speaker 2: best case scenario come together, like you talk in the

1238
01:00:19,680 --> 01:00:23,640
Speaker 2: book about building these computers, how you like search for

1239
01:00:23,680 --> 01:00:25,920
Speaker 2: the origin of life? And when I do science, I

1240
01:00:26,000 --> 01:00:28,400
Speaker 2: was trying to imagine, like, what's the fantasy data I

1241
01:00:28,400 --> 01:00:31,400
Speaker 2: would have? Are you hoping that we discover like alien

1242
01:00:31,440 --> 01:00:34,280
Speaker 2: life here on Earth before we discover it on Enzi?

1243
01:00:34,320 --> 01:00:37,240
Speaker 2: Let us would actually be your preference take us through

1244
01:00:37,240 --> 01:00:38,840
Speaker 2: your scientific fantasy, right?

1245
01:00:39,000 --> 01:00:41,800
Speaker 6: So my preference is that we just discover more life

1246
01:00:41,840 --> 01:00:43,880
Speaker 6: and we understand what life is. So my preference is

1247
01:00:44,400 --> 01:00:48,800
Speaker 6: understand what life is and have enough scientific evidence to

1248
01:00:48,800 --> 01:00:52,320
Speaker 6: support that explanation. The progress of science is that's never

1249
01:00:52,320 --> 01:00:55,440
Speaker 6: a single aha moment. It's like, you know, a cultural transformation.

1250
01:00:55,480 --> 01:00:57,240
Speaker 6: And the way we understand a certain set of phenomena

1251
01:00:57,360 --> 01:01:00,320
Speaker 6: mediated by a whole bunch of experiments and observations and

1252
01:01:00,400 --> 01:01:03,400
Speaker 6: a consilience of like a whole bunch of things coming together, right,

1253
01:01:03,480 --> 01:01:06,560
Speaker 6: So I think that process is highly nonlinear. For me,

1254
01:01:06,640 --> 01:01:11,000
Speaker 6: the reason I really advocated more for this experimental approach

1255
01:01:11,480 --> 01:01:13,880
Speaker 6: in the lab is the idea that you could iterate

1256
01:01:13,920 --> 01:01:17,400
Speaker 6: between the observation and theory very quickly. So the challenge

1257
01:01:17,400 --> 01:01:20,439
Speaker 6: for looking for life on alien worlds is we don't

1258
01:01:20,480 --> 01:01:22,560
Speaker 6: know the prior probability for life, and we don't know

1259
01:01:22,600 --> 01:01:25,520
Speaker 6: what we're looking for, and so we don't know how

1260
01:01:25,520 --> 01:01:27,920
Speaker 6: many planets we have to survey before we find something,

1261
01:01:27,960 --> 01:01:29,480
Speaker 6: and nor is it the case that we can actually

1262
01:01:29,520 --> 01:01:32,040
Speaker 6: rule out a planet is alive or not. And so

1263
01:01:32,120 --> 01:01:34,680
Speaker 6: I think by trying to bring the paradigm of looking

1264
01:01:34,680 --> 01:01:37,680
Speaker 6: for alien life into an experimental paradigm, and when we

1265
01:01:37,560 --> 01:01:40,320
Speaker 6: were actually building large enough chemical search engines to look

1266
01:01:40,360 --> 01:01:43,640
Speaker 6: for alien life, we actually make it tractable to understand

1267
01:01:43,680 --> 01:01:47,360
Speaker 6: the mechanism of the original life, the probability it doesn't happen,

1268
01:01:47,840 --> 01:01:50,120
Speaker 6: and also build the theory and experiments to really test

1269
01:01:50,160 --> 01:01:52,120
Speaker 6: how it does happen at the same time. So to me,

1270
01:01:52,200 --> 01:01:54,200
Speaker 6: it seems the most efficient route to get actually getting

1271
01:01:54,200 --> 01:01:57,560
Speaker 6: to the answer to the question. And so and you know,

1272
01:01:57,640 --> 01:01:59,440
Speaker 6: part of it might be biased by my background in

1273
01:01:59,440 --> 01:02:02,000
Speaker 6: cosmology and just looking at the way that particle physicists

1274
01:02:02,000 --> 01:02:05,080
Speaker 6: and cosmology have collaborated to really like, you know, why

1275
01:02:05,080 --> 01:02:07,040
Speaker 6: do we understand the mechanisms of like the Big Bang

1276
01:02:07,120 --> 01:02:07,479
Speaker 6: so well.

1277
01:02:07,400 --> 01:02:09,160
Speaker 5: It's because we build particle accelerators.

1278
01:02:10,240 --> 01:02:12,840
Speaker 6: And so I think without an experimental paradigm for these

1279
01:02:12,920 --> 01:02:16,400
Speaker 6: questions that really ties the planetary and the alien search

1280
01:02:16,440 --> 01:02:18,680
Speaker 6: to the original life, you have to couple those problems

1281
01:02:18,720 --> 01:02:21,240
Speaker 6: through the same problem at their core. And I also

1282
01:02:21,320 --> 01:02:23,320
Speaker 6: just like the radical idea that like alien life will

1283
01:02:23,320 --> 01:02:26,040
Speaker 6: discover it on Earth and an experiment because it's fun,

1284
01:02:27,040 --> 01:02:27,640
Speaker 6: but then we'll.

1285
01:02:27,520 --> 01:02:29,520
Speaker 5: Know what we're looking for, so like it seems more.

1286
01:02:29,400 --> 01:02:32,040
Speaker 6: Obvious we find it elsewhere, right, So like to me,

1287
01:02:32,120 --> 01:02:34,760
Speaker 6: that just seems logical, but it's also fun because you know,

1288
01:02:34,840 --> 01:02:36,800
Speaker 6: like it means we can do the science really rapidly,

1289
01:02:36,840 --> 01:02:39,240
Speaker 6: and I want to see it solved, so I want

1290
01:02:39,280 --> 01:02:41,080
Speaker 6: the most efficient route to an answer.

1291
01:02:40,720 --> 01:02:42,440
Speaker 2: And then we'll have to argue about whether it's really

1292
01:02:42,480 --> 01:02:44,200
Speaker 2: alien if it was on Earth Nater.

1293
01:02:44,600 --> 01:02:48,200
Speaker 6: Right, that's a good problem to have, right, because I think, yeah,

1294
01:02:48,320 --> 01:02:49,400
Speaker 6: a really good problem to have.

1295
01:02:49,560 --> 01:02:51,560
Speaker 3: Come full circle to good beer conversation.

1296
01:02:51,760 --> 01:02:53,560
Speaker 5: Yes, yes, there you go.

1297
01:02:53,640 --> 01:02:55,440
Speaker 6: See if you answer one of the beer questions, but

1298
01:02:55,480 --> 01:02:57,200
Speaker 6: you have a better beer question, it's not a problem

1299
01:02:57,520 --> 01:02:59,080
Speaker 6: you yep.

1300
01:02:59,240 --> 01:03:01,120
Speaker 2: Well, thank you much for coming on and talk to

1301
01:03:01,160 --> 01:03:04,480
Speaker 2: us about assembly theory and for giving us an advanced

1302
01:03:04,480 --> 01:03:07,720
Speaker 2: peak at your book. Everyone, it's called Life As No

1303
01:03:07,840 --> 01:03:11,360
Speaker 2: One Knows It, The physics of Life's emergence. Congratulations on

1304
01:03:11,440 --> 01:03:12,520
Speaker 2: the book and best of luck.

1305
01:03:12,800 --> 01:03:14,880
Speaker 5: Thank you so much, Thank you both.

1306
01:03:15,160 --> 01:03:17,160
Speaker 3: Yeah, thank you all.

1307
01:03:17,160 --> 01:03:19,560
Speaker 2: Right, And that was our conversation with Sarah and Marie Walker,

1308
01:03:19,640 --> 01:03:22,480
Speaker 2: author of the recent book Life As No One Knows It,

1309
01:03:22,520 --> 01:03:26,280
Speaker 2: which you can now pick up at all fine booksellers. Kelly,

1310
01:03:26,280 --> 01:03:28,680
Speaker 2: what's your takeaway? Is physics going to help us understand

1311
01:03:28,680 --> 01:03:29,280
Speaker 2: what life is?

1312
01:03:29,720 --> 01:03:33,040
Speaker 1: Well, you know, my takeaway is pretty similar to my

1313
01:03:33,080 --> 01:03:35,760
Speaker 1: takeaway many years ago when I was arguing with my

1314
01:03:35,840 --> 01:03:39,720
Speaker 1: fellow grad students, which is, Wow, this is complicated, which

1315
01:03:39,760 --> 01:03:42,680
Speaker 1: is pretty much the conclusion to every ecology paper you'll

1316
01:03:42,720 --> 01:03:46,600
Speaker 1: ever read is it's complicated and it depends and anyway,

1317
01:03:46,680 --> 01:03:48,800
Speaker 1: So yeah, it's complicated.

1318
01:03:48,800 --> 01:03:49,400
Speaker 3: What do you think.

1319
01:03:49,600 --> 01:03:52,280
Speaker 2: I think it's a valiant effort and it's worth doing,

1320
01:03:52,360 --> 01:03:55,000
Speaker 2: and we're going to learn things along the way. I

1321
01:03:55,080 --> 01:03:57,560
Speaker 2: don't know that we're going to figure it out. I

1322
01:03:57,600 --> 01:04:00,120
Speaker 2: don't know this is the right approach, but I think

1323
01:04:00,160 --> 01:04:02,840
Speaker 2: thinking hard about it is the first step to figuring

1324
01:04:02,880 --> 01:04:05,800
Speaker 2: it out. No matter where it goes. Often you go

1325
01:04:05,920 --> 01:04:07,840
Speaker 2: down to the root of something and you discover something

1326
01:04:07,880 --> 01:04:11,120
Speaker 2: completely different than solving the problem you meant to, or

1327
01:04:11,160 --> 01:04:14,760
Speaker 2: you make breakthroughs in other areas. So I'm excited to

1328
01:04:14,800 --> 01:04:17,120
Speaker 2: see where this goes. I'm excited that people are thinking

1329
01:04:17,160 --> 01:04:19,960
Speaker 2: about these problems. I think it helps clear away some

1330
01:04:20,000 --> 01:04:22,200
Speaker 2: of the cobwebs and provides a little bit of clarity.

1331
01:04:22,560 --> 01:04:23,880
Speaker 2: But I guess I have to put it into like

1332
01:04:24,120 --> 01:04:27,160
Speaker 2: we'll see category before I'm actually convinced that this is

1333
01:04:27,200 --> 01:04:28,960
Speaker 2: the right way to think about life.

1334
01:04:29,160 --> 01:04:32,200
Speaker 1: I mean, it would be pretty epic if like on

1335
01:04:32,320 --> 01:04:34,640
Speaker 1: demand new life could be created in the lab and

1336
01:04:34,680 --> 01:04:37,400
Speaker 1: we could look at different evolutionary trajectories and stuff like that.

1337
01:04:37,440 --> 01:04:39,720
Speaker 1: I mean, the evolutionary biologist would go wild if that

1338
01:04:39,760 --> 01:04:42,480
Speaker 1: could be accomplished. I don't know where you start to

1339
01:04:42,560 --> 01:04:45,000
Speaker 1: do something like that, but it would be pretty exciting

1340
01:04:45,040 --> 01:04:46,080
Speaker 1: if it could be accomplished.

1341
01:04:46,400 --> 01:04:49,360
Speaker 2: Yeah. And then, of course, the next philosophical question would be,

1342
01:04:49,680 --> 01:04:52,400
Speaker 2: if you've created a new kind of living goo in

1343
01:04:52,440 --> 01:04:54,960
Speaker 2: your lab, is it an alien or is it just

1344
01:04:55,000 --> 01:04:55,960
Speaker 2: another kind of earthling?

1345
01:04:56,200 --> 01:04:59,880
Speaker 1: And how long before it begins to eat human flesh?

1346
01:05:01,160 --> 01:05:03,760
Speaker 2: Day one? I'm hoping. I mean, if this movie's going

1347
01:05:03,840 --> 01:05:04,400
Speaker 2: to be any.

1348
01:05:04,240 --> 01:05:07,040
Speaker 3: Good, right, you know it's gonna happen fast.

1349
01:05:07,920 --> 01:05:08,120
Speaker 4: Yeah.

1350
01:05:08,760 --> 01:05:10,840
Speaker 2: I mean you could also flip the question around and like,

1351
01:05:10,960 --> 01:05:13,160
Speaker 2: say that new kind of living goo becomes intelligent, how

1352
01:05:13,200 --> 01:05:15,320
Speaker 2: do we know it doesn't call us aliens? Right? And

1353
01:05:15,400 --> 01:05:17,480
Speaker 2: like we're at home, how can we be aliens?

1354
01:05:17,800 --> 01:05:20,360
Speaker 1: That's right, that's right, let's all just get along and

1355
01:05:20,360 --> 01:05:21,480
Speaker 1: be earth right.

1356
01:05:22,520 --> 01:05:25,400
Speaker 2: That sounds good exactly. I look forward to a big,

1357
01:05:25,480 --> 01:05:28,440
Speaker 2: cozy family meal, passing the bread and the corn cobs

1358
01:05:28,440 --> 01:05:30,280
Speaker 2: around with our fellow earth goo.

1359
01:05:30,600 --> 01:05:33,000
Speaker 1: I'm going to schedule it one week after our meeting,

1360
01:05:33,000 --> 01:05:35,040
Speaker 1: where you tell me about how physics has solved all

1361
01:05:35,040 --> 01:05:35,960
Speaker 1: the problems of the world.

1362
01:05:36,400 --> 01:05:38,080
Speaker 2: Sounds good, and I'll bring some towels.

1363
01:05:38,800 --> 01:05:39,960
Speaker 3: That's good because I'll forget mine.

1364
01:05:40,000 --> 01:05:43,360
Speaker 2: Bring extra please, Katrina will have an extra one in

1365
01:05:43,400 --> 01:05:46,400
Speaker 2: her bag. No worries, all right. Thanks everyone for joining

1366
01:05:46,480 --> 01:05:49,560
Speaker 2: us on this squishy discussion about the physics of life.

1367
01:05:49,600 --> 01:05:51,800
Speaker 2: Hope you learned something I certainly did. And thank you

1368
01:05:51,880 --> 01:05:54,840
Speaker 2: very much Kelly, my friend and co host, for joining

1369
01:05:54,920 --> 01:05:55,880
Speaker 2: me on today's.

1370
01:05:55,600 --> 01:05:57,040
Speaker 1: Episode My Pleasure.

1371
01:05:57,200 --> 01:05:57,880
Speaker 3: Thanks Daniel.

1372
01:05:59,320 --> 01:06:06,640
Speaker 2: Tune in next time time For more science and curiosity.

1373
01:06:06,680 --> 01:06:09,520
Speaker 2: Come find us on social media, where we answer questions

1374
01:06:09,560 --> 01:06:14,000
Speaker 2: and post videos. We're on Twitter, Discorg, Insta, and now TikTok.

1375
01:06:14,680 --> 01:06:17,520
Speaker 2: Thanks for listening, and remember that Daniel and Jorge Explain

1376
01:06:17,560 --> 01:06:21,520
Speaker 2: the Universe is a production of iHeartRadio. For more podcasts

1377
01:06:21,600 --> 01:06:26,240
Speaker 2: from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever

1378
01:06:26,280 --> 01:06:28,000
Speaker 2: you listen to your favorite shows.