Pod Insights StarTalk Podcast The Origins of Life with Sara Imari Walker About this episode What is life? Neil deGrasse Tyson and co-host Chuck Nice tackle assembly theory, artificial life, and the origin of lifeforms in the universe as we revise the definition of life with astrobiologist and theoretical physicist Sara Imari Walker.
Transcript 10,176 words · 4 speakers
Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.
0:00 Neil deGrasse Tyson? So Chuck. Yeah. Did, I don't know if we answered all those profound questions, but we certainly went there. We certainly did. What is life as we know it? Is that understood? And if it is or isn't, what is life as we don't know it? Right. And as long as we're talking about life, is AI alive? AI life itself. Right. Yes. Right. It better not be because soon it will be asking for a raise and all kinds of rights and oh, it's gonna be a mess. Coming up, life in a nutshell and outside of the nutshell on StarTalk.
0:34 Neil deGrasse Tyson? Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now.
0:47 Neil deGrasse Tyson? This is StarTalk. Neil deGrasse Tyson, your personal astrophysicist, got with me, of course, Chuck Knight. Hey Neil, what's happening? Lord Chuck Knight. Oh, thank you, yes. All right, my co-host, professional comedian, stand-up comedian. Yes. And. Not always the same thing, a professional comedian and stand-up comedian. And actor. And actor. I've seen you in some TV commercials. Acting like a comedian, you know. Almost dropped my sandwich when I saw that. Uh, there's, I'm actually gonna do a sandwich commercial next.
1:18 Neil deGrasse Tyson? All right, no, good, good that you're out there. Yeah, yeah, that'll, that'll keep it moving. And we can say, we knew you when. You gonna know me then too.
1:27 Neil deGrasse Tyson? So wonderful topic today. Yeah. Oh my, I love it. Yeah. Love me this topic. It's a rich, rich topic. So there's always been this concept of life as we know it. Right. And never caught on as an acronym, Locky, life as we know it. I wonder why?
1:43 Neil deGrasse Tyson? Such a mellifluous acronym, Locky. Never caught on. Life as we know, it's like carbon based, you know, all the, all the usual things that you throw into the mix. And there's been some effort lately. Okay. To think about life as we don't know it. Ooh, now I like, that is far more intriguing. And, and, and that seems to me opens up all manner of possibilities. Absolutely. Outside of the box that we've put ourselves in. Right. So we have a world's expert. We have Sarah, you have three names, Sarah, as do I. Uh, Sarah Amari Walker.
2:19 Speaker 01 That's me.
2:20 Neil deGrasse Tyson? And which one do we go by?
2:21 Speaker 01 Sarah.
2:22 Neil deGrasse Tyson? Sarah, okay, we'll do that. Oh, thanks for making it simple.
2:25 Speaker 01 I tried.
2:25 Chuck Nice? We appreciate that.
2:26 Speaker 01 Really tried.
2:27 Neil deGrasse Tyson? So Sarah, you're you're an astrobiologist and physicist, theoretical physicist. So you're coming to this life question not from the normal trackings of a biologist. Because who else would you think to bring to the table when you're talking about life, if not a biologist?
2:43 Chuck Nice? Absolutely.
2:44 Neil deGrasse Tyson? But now you're going to bring some physics into the equation, and I love me some physics.
2:48 Speaker 01 Yeah, me too.
2:49 Neil deGrasse Tyson? The buck stops at physics.
2:51 Speaker 01 Yeah.
2:51 Neil deGrasse Tyson? Okay, there's an old saying, there's no understanding of biology without chemistry.
2:56 Chuck Nice? Right.
2:57 Neil deGrasse Tyson? And there's no understanding of chemistry without physics.
2:59 Chuck Nice? There you go. Somehow your subject of expertise be lords over the law. I don't know how this happened.
3:07 Neil deGrasse Tyson? So what brought you to the question of life?
3:10 Speaker 01 Yeah, I'm really interested in fundamental laws of nature and where we might find new ones. So I think this is the main motivator for me is to think about life being explained by some universal physics we don't know yet.
3:21 Neil deGrasse Tyson? Whoa. Okay, that's whoa.
3:25 Chuck Nice? Damn, Sarah coming in hot.
3:28 Speaker 01 The only way I know to go.
3:29 Chuck Nice? Sarah is not playing around, buddy.
3:31 Neil deGrasse Tyson? Didn't even warm up to that one.
3:33 Chuck Nice? I'm telling you.
3:35 Chuck Nice? It's like, why don't you take a couple of warm up tosses? All right, we clocked that one at 97 miles an hour. That's fantastic.
3:43 Neil deGrasse Tyson? So so who so I don't I can't think of a department, a traditional department in a university that would serve this cause. And now I learn you're deputy director of the Beyond Center?
3:56 Speaker 01 Yes.
3:57 Neil deGrasse Tyson? That's audacious.
3:58 Chuck Nice? Now you guys are the people that make the meat, right?
4:01 Neil deGrasse Tyson? The Beyond Meat?
4:02 Speaker 01 No, we don't make meat. That was it. Yeah, it's okay. No, we don't do anything like that. We're actually, it's like the full name of the center is the Beyond Center for Fundamental Concepts in Science. So we're actually an exploratory center based at Arizona State, and we think about deep problems.
4:14 Neil deGrasse Tyson? University.
4:15 Speaker 01 Yep.
4:15 Neil deGrasse Tyson? Not just in the state of Arizona.
4:17 Speaker 01 No, not, yeah, Arizona.
4:18 Neil deGrasse Tyson? So you're you're on the faculty there?
4:19 Speaker 01 Mm hmm. That's right.
4:20 Neil deGrasse Tyson? Yeah, ASU, they have really good astro folk there, too.
4:23 Chuck Nice? Okay.
4:24 Neil deGrasse Tyson? Yeah, no, I know ASU.
4:25 Chuck Nice? All right.
4:26 Neil deGrasse Tyson? Yeah, yeah. And so this Beyond Center, are you co-founder of that?
4:31 Speaker 01 No, the founder is Paul Davies, but I'm the deputy director.
4:35 Neil deGrasse Tyson? We know Paul Davies. Yeah, an astrophysicist, like from way back.
4:39 Speaker 01 Yeah.
4:39 Neil deGrasse Tyson? Yeah.
4:40 Speaker 01 I like hanging out with cosmologists, so and the Beyond Center is in the cosmology, like it's in the cosmology wing on ASU on like on the campus.
4:47 Neil deGrasse Tyson? Okay, I was looking at. At least one of your research papers, you have collaborators, some of whom are based in the Santa Fe Institute, which is also one of these beyond.
4:58 Speaker 01 Yes.
4:58 Neil deGrasse Tyson? I mean, they specialize in, here's what everybody's thinking, but we're gonna put a foot outside that circle.
5:04 Chuck Nice? Now, let's go beyond.
5:05 Neil deGrasse Tyson? Let's go beyond.
5:06 Chuck Nice? Right.
5:06 Neil deGrasse Tyson? Right? So you're teaming up with other beyond people.
5:09 Speaker 01 Yes, I like hanging out with people that think outside the box. They're my favorite kind of people.
5:14 Neil deGrasse Tyson? In fact, the sum of stuff I've been working on is not just the box, because box is a three-dimensional object.
5:20 Chuck Nice? Right.
5:20 Neil deGrasse Tyson? She's thinking beyond the tesseract.
5:22 Chuck Nice? Oh, wow. Look at that.
5:25 Speaker 01 Now, I have pretty shapes in my head. I like this.
5:29 Neil deGrasse Tyson? So, so, so, tell me, I know there might have been adjustments over the decades, but today, what is the commonly held definition of life itself?
5:38 Speaker 01 The way that I consider it is that we actually don't need to define life. We need to figure out a theory that helps us derive the properties of life. So we should be able to predict features of life anywhere it should occur in the universe. So that's been my approach. It's very, you know, theoretical physicist. Need to build theories, need to explain regularities in nature.
5:55 Neil deGrasse Tyson? She's got theoretical physics bad.
5:56 Chuck Nice? I love it.
5:58 Neil deGrasse Tyson? It's bad in you.
5:59 Speaker 01 It's never coming out.
6:01 Chuck Nice? Yeah, it's a little fever with you. You got a little fever.
6:05 Speaker 01 Yeah, I do.
6:06 Chuck Nice? So, I mean, basically, you're like, let's not worry about identifying. Let's find out what creates the identification?
6:16 Speaker 01 Yes.
6:17 Neil deGrasse Tyson? In the first place.
6:17 Speaker 01 Yes.
6:18 Chuck Nice? Wow.
6:19 Neil deGrasse Tyson? How do you go about doing that?
6:20 Speaker 01 So I started, you know, in a true theorist fashion. I had probably like seven or eight working definitions, but I was trying to find, you know, what's the commonality under them. But a lot of them were about something to do with information structuring matter was kind of the early way I was thinking about it.
6:34 Chuck Nice? Wow, okay, I got you, because then that gets you all the way down to single cells, because even they are carrying information. So if you get to the root of the information and what creates the information, then it may not even be a cell that you're working with. It could be something outside of that.
6:53 Speaker 01 Yep, and a cell's a good example, because it's very complex and we don't think they can form outside of evolution. So the way that we talk about these ideas now, which is what I'm really excited about is this theory, assembly theory I've been working on with my collaborator Lee Cronin.
7:05 Chuck Nice? Assembly.
7:06 Speaker 01 Theory.
7:06 Chuck Nice? Assembly theory.
7:07 Speaker 01 It's a theory. As a theorist should do. Yeah. So, assembly theory's key conjecture about the nature of life is life is the only physics that can generate complex objects.
7:16 Chuck Nice? Interesting.
7:17 Speaker 01 Like a cell.
7:18 Chuck Nice? Right.
7:19 Speaker 01 Or a microphone, or a comedian.
7:23 Chuck Nice? We're not that complex, unfortunately. He's very simple. We're the simplest of all life.
7:29 Neil deGrasse Tyson? Wait, so you are declaring that rocks and crystals and things is not complex. So therefore, while you could in principle
7:41 Neil deGrasse Tyson? create those out of your modeling or out of your theories, that's not your target of interest?
7:45 Speaker 01 So, the nature of how we define complexity is it doesn't happen spontaneously, it requires evolution. So there are some kinds of rocks and minerals that do require, say, technology to precisely engineer defects in a crystal, like if you want a perfect diamond or something.
8:00 Chuck Nice? Exactly.
8:00 Speaker 01 Or, so there would be rocks, maybe that pass the boundary of life, but they would be something life created or engineered.
8:06 Neil deGrasse Tyson? So I love this because you're, you, you poured out the mold and you said, "Let me start from scratch." And if you start from scratch, you're not biased by any pre-existing construct for what is or could or should be.
8:24 Chuck Nice? Right.
8:25 Neil deGrasse Tyson? Now you, you can make almost anything that has complexity.
8:30 Speaker 01 Yes.
8:30 Neil deGrasse Tyson? And the space of complexities is then what you will study.
8:34 Speaker 01 Yes, and that space is huge. So, as an astronomical example, you know, I like to use this molecule taxol as an example. It's molecular weight's about 853.
8:43 Neil deGrasse Tyson? Taxol, what do we do with that?
8:45 Speaker 01 Taxol's an anti-cancer drug. It's just one molecule that bio, that's been created in a tree somewhere. It's a fat molecule, it's a big molecule, but if you wanted to make-
8:53 Neil deGrasse Tyson? How many atoms are in that molecule?
8:54 Speaker 01 Um.
8:55 Neil deGrasse Tyson? Approximately? I mean, hundreds or-
8:57 Speaker 01 I think, no.
8:58 Neil deGrasse Tyson? Gobs and gobs.
8:58 Speaker 01 I think it's like, a couple hundred.
9:01 Neil deGrasse Tyson? Yeah, so on that order.
9:02 Speaker 01 Yeah, a hundred to two hundred. But if you wanted to make one molecular structure of the same molecular formula, like every single three-dimensional conformation, it would fill a volume of about one and a half universes. Just one molecular formula.
9:17 Speaker 01 One centimeter, one molecule per centimeter is huge. This is how big chemical space is. The reason it's hard to make complex objects is there's so many of them. So, evolution is necessary to select in that space.
9:26 Neil deGrasse Tyson? Uh huh.
9:27 Speaker 01 So, you like, we can't have a universe and a half full of just taxol. It'd be very boring.
9:32 Neil deGrasse Tyson? Right.
9:32 Speaker 01 We live in a universe with lots of different complex objects.
9:35 Neil deGrasse Tyson? Wait, I have to, let me repeat what I think you said. That the complexity of, what's it called again?
9:40 Speaker 01 Taxol.
9:41 Neil deGrasse Tyson? Taxol.
9:42 Speaker 01 It's not a special molecule either. I just picked one out of a hat.
9:45 Neil deGrasse Tyson? Yeah, we all have these in our hat, don't we?
9:47 Chuck Nice? Yeah, I'm carrying around a hat with lots of taxol in it. So, it's more like a ski mask.
9:53 Neil deGrasse Tyson? If I think I understand you.
9:55 Speaker 01 Yeah.
9:56 Neil deGrasse Tyson? The complexity of this molecule is such that if you explored all molecules that could be that complex, there's not enough room in the universe to contain it.
10:08 Speaker 01 That's right.
10:08 Neil deGrasse Tyson? So, clearly, that molecule's existence comes from some prior requirement or urging.
10:17 Chuck Nice? For that configuration.
10:17 Neil deGrasse Tyson? For that configuration, right.
10:18 Speaker 01 Yes, that's exactly right.
10:20 Neil deGrasse Tyson? That's fair.
10:21 Speaker 01 That's exactly right.
10:21 Chuck Nice? So, let me ask you this then, because now I'm a little, you'll have to forgive my ignorance, but I'm the only non-scientist here. Thank God, uh, so I can say stupid stuff.
10:31 Neil deGrasse Tyson? God had nothing to do with that.
10:33 Chuck Nice? That's a very complex molecule. Okay. Okay. Um, where exactly does spontaneity and selection cross? And how do you identify which is which? Which is, which is a progression and which is a cross?
10:53 Speaker 01 Yeah. So, you know, the kinds of very simple molecules that might happen on a planet, you know, can happen spontaneously. Or if you're thinking like Lego are easier for people than chemistry. If you have like a tray with a bunch of Lego in it and you shake it, you're going to get some Lego sticking together and making simple shapes. So, those would be spontaneous objects. But you're not going to be able to shake it long enough to have Hogwarts Castle spontaneously emerge out of it. That would require a process of evolution and refinement.
11:19 Chuck Nice? And a wand.
11:20 Speaker 01 And a wand, yeah. No magic though. The universe doesn't have magic.
11:23 Chuck Nice? Oh.
11:25 Speaker 01 At least not in this scenario, so, um.
11:28 Chuck Nice? She's covering her bases. She's like, you know what? She's in a beyond. He was like, I am a theorist. No, but she's in a beyond, you gotta leave her move for the rest of Rome. Right. For the one. Go ahead.
11:38 Speaker 01 Well, I like, you know, magic for me is yet to be, you know, regularized in theoretical physics. So there still always has to be other things for us to do.
11:45 Neil deGrasse Tyson? Any sufficiently advanced technology is indistinguishable from magic.
11:48 Speaker 01 That's right. Or the laws of physics.
11:51 Chuck Nice? Good. Wow. Okay. So go ahead, back to you can't get to the place of where you could shake it and then have Hogwarts. So.
11:59 Neil deGrasse Tyson? So if you do shake it and some stick together, those are like the amino acids?
12:03 Speaker 01 Yes.
12:03 Chuck Nice? Gotcha.
12:04 Speaker 01 Yes.
12:04 Neil deGrasse Tyson? Because we did, we did that with the Miller-Urey experiment.
12:07 Speaker 01 That's right.
12:08 Neil deGrasse Tyson? Where he just throws some basic.
12:10 Chuck Nice? Okay, you explain that, please?
12:11 Neil deGrasse Tyson? Everybody knows that.
12:13 Chuck Nice? Clearly, they don't. Okay. And by the way, of course, I know, I'm just talking about the people out there.
12:18 Neil deGrasse Tyson? No, they don't.
12:21 Chuck Nice? I mean, there may be someone.
12:23 Neil deGrasse Tyson? Please regale us of the Miller-Urey experiment.
12:25 Speaker 01 Yeah, so Stanley Miller was a PhD student. I think he published a paper in 1953, so it was a long time ago. But basically, he put, you know, a bunch of molecules that might have been available on the early Earth in a flask and put some lightning in his flask and tried to model.
12:39 Neil deGrasse Tyson? As a source of energy.
12:40 Speaker 01 Yes, as a source of energy. And he had a reducing environment. And then, you know, he got amino acids out of it.
12:46 Neil deGrasse Tyson? Oxygen is taken out.
12:47 Speaker 01 Yeah. And so he made amino acids. And, you know, people were so shocked by this at the time. They thought little aliens were being crawling out of, you know, life forms would be crawling out of the test tube in a couple of weeks, but that's not what happened.
12:57 Chuck Nice? Right.
12:57 Speaker 01 Unfortunately.
12:58 Chuck Nice? Yeah.
12:59 Neil deGrasse Tyson? The reducing environment is that we think the early Earth did not have free oxygen.
13:02 Chuck Nice? Oxygen.
13:02 Neil deGrasse Tyson? Right. So he's trying to, if, if life's formed on Earth under these conditions.
13:06 Chuck Nice? You gotta create the conditions under which it formed.
13:08 Neil deGrasse Tyson? So what came, so out of the ooze, nothing crawled out?
13:11 Speaker 01 Nothing crawled out. If you run the experiment long enough, you basically get what we call a tar in prebiotic chemistry, which is just an undifferentiated mess of a whole bunch of organic molecules that we can't identify.
13:20 Neil deGrasse Tyson? Okay. Prebiotic chemistry means what?
13:23 Speaker 01 Prebiotic chemistry means chemistry that could plausibly happen on the early Earth in the absence of life.
13:28 Neil deGrasse Tyson? Before you have life.
13:29 Speaker 01 Before you have life.
13:30 Neil deGrasse Tyson? So it's organic chemistry.
13:31 Speaker 01 Yeah. Yeah, I like the word organic chemistry better because prebiotic kind of makes it sound like it's predisposed to become biological, but there's no teleology, there's no direction.
13:38 Chuck Nice? It also makes it sound like something you take before a meal.
13:40 Speaker 01 Yeah. That's true. People do confuse it with probiotic all the time.
13:44 Chuck Nice? Oh, my gosh.
13:46 Speaker 01 All that probiotic chemistry.
14:01 Speaker 03 I'm Ali Khan Hemraj and I support StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson.
14:18 Neil deGrasse Tyson? So, alright, so I like the, the, the, the basic principles that are being invoked here. Very, very simple.
14:25 Speaker 01 Yes.
14:25 Neil deGrasse Tyson? Basic principles. Okay, so now you have, you shake the Legos, some stick together, now what?
14:30 Speaker 01 Now, selection needs to happen to get to something like Hogwarts, which means that some parts have to start being, uh, you know, abundant in the environment and then reused to be, build further structure.
14:40 Neil deGrasse Tyson? And these, these become your units of, your building units?
14:43 Speaker 01 Yes.
14:44 Neil deGrasse Tyson? Your bricks?
14:44 Speaker 01 That's right, yes.
14:45 Neil deGrasse Tyson? To build the edifice?
14:46 Speaker 01 Yes.
14:47 Chuck Nice? And you say selection because they are selected to succeed, is that the idea?
14:51 Speaker 01 Yes, and also because selection is excluding that huge space of other possibilities.
14:55 Neil deGrasse Tyson? You have to, otherwise you're lost in space.
14:58 Speaker 01 That's right.
14:58 Neil deGrasse Tyson? Yeah.
14:59 Speaker 01 I don't even want to know how many possible configurations there are of the Legos in the Lego Hogwarts set. It's like 2,000 Lego, if you imagine all the things you could build out of that, it's crazy.
15:07 Neil deGrasse Tyson? It's three universes.
15:08 Speaker 01 Yeah.
15:09 Chuck Nice? So now, so now, since you're looking for life outside of this,
15:14 Speaker 01 Mm-hmm.
15:15 Chuck Nice? let's consider in the selection that-
15:18 Neil deGrasse Tyson? What's life outside of what?
15:19 Chuck Nice? I'm saying, outside of the life that we know.
15:21 Neil deGrasse Tyson? Oh, yeah.
15:21 Speaker 01 Right.
15:22 Chuck Nice? Right, you're looking for life outside-
15:23 Speaker 01 Other planets, even.
15:24 Chuck Nice? So, let's go back to the primordial soup of another planet, and we have the shaken Legos.
15:33 Speaker 01 Mm-hmm.
15:34 Chuck Nice? Okay, um, but, are there circumstances that maybe led to selection for the development here, that may be different there, creating something different entirely? Could that possibly be the case?
15:52 Speaker 01 Yes, I think so. So I think Assembly Theory would predict yes. Because the possibility space of the chemistry is so large. And what we've actually been able to do is define a threshold that we expect life to emerge, which is what you described as this spontaneous to selection dynamics. And it actually has, you know, for the physics nerds out there, it has like properties of a phase transition, right? So you go from spontaneous, like random configurations of objects to selected ones that have this historical pathway.
16:16 Neil deGrasse Tyson? The phase transition is, all the molecules are this way, and then- Like a moment later, they're in a whole other way. Figuration. Yeah. So, so, but we, we live this.
16:25 Speaker 01 Yeah.
16:25 Neil deGrasse Tyson? Right. Okay. Uh, we, we, it's our fancy word for it, but when water becomes ice. Ice. Ice is not water. Right. That's a phase transition. When water becomes steam, it's a phase transition. There you go. And so we actually generalize that term even in the early universe. If the, if there's, everything is this way, and then something happens, and then it's another way, we just call it a phase transition. Gets us through.
16:48 Speaker 01 We geek out on that.
16:49 Neil deGrasse Tyson? Yeah.
16:49 Speaker 01 We physicists love phase transitions.
16:51 Neil deGrasse Tyson? Anything can happen through a phase transition. Right. And, uh, like spooky things, fun things. Yes. Dangerous things. Yes. So I shake the Legos. Some of them stick together. They're the Lego counterpart to amino acids.
17:05 Speaker 01 Mm-hmm.
17:05 Neil deGrasse Tyson? This was done in the Miller-Urey experiment. It's amino acids, which are the building blocks of protein, the building blocks of life as we know it. Right. All right. On another planet, you shake it, we're thinking it'll also make amino acids. So this becomes a unit of life. Let's call it that. Or your AI, your, what's AT? What, what's the?
17:26 Speaker 01 Assembly theory, AT. We, we call, we talk about assembly index is the number of steps to make an object.
17:31 Neil deGrasse Tyson? So that's a step.
17:32 Speaker 01 Yeah.
17:32 Neil deGrasse Tyson? That's a step.
17:33 Speaker 01 Okay.
17:33 Neil deGrasse Tyson? If that's the same step everywhere.
17:35 Speaker 01 Yeah.
17:35 Neil deGrasse Tyson? Then that greatly limits what comes after, because you're not starting, not everything is possible in that early first unit.
17:44 Speaker 01 Yeah, this is a great point. The, the interesting thing there is how varied geochemistry is on different planets. And actually, even if you look at amino acids, there's hundreds of them that we've identified in meteorites.
17:53 Neil deGrasse Tyson? Right, and not all of them.
17:55 Speaker 01 Not all of them are in biology.
17:56 Neil deGrasse Tyson? Right. So if you find them in meteorites, it means that they're. They're out there. They're out there. They're being made. They're being made. But they're not here. Or, or even if they come here, we're not using them. Well, right. They're, they're, they don't serve a purpose here. Right, exactly. Okay, go on. That's the point.
18:08 Speaker 01 Yeah, so, um, so I don't think that we should have an expectation that all the steps on the pathway to something as complex as cell would be the same. Because, you know, maybe the first few are similar, but as you build up the complexity, the chemistry, there's so many paths you could take, so many kinds of molecules, that there should be a point where planets start to diverge in what kind of. Biochemistry evolves out of the geochemistry.
18:29 Chuck Nice? So let's, okay.
18:32 Speaker 01 Aliens can be really weird.
18:33 Chuck Nice? That's what I was gonna, that's what I was gonna get to. It's like, it sounds to me like a, like a virus could be an alien. Like, highly effective, like, lots of information, carrying out, like, you know, purpose, procreating, you know, I mean, it, when you, if, if you can look for something like that, how do you even begin to narrow the search once you start looking out there?
19:03 Speaker 01 Yeah, so the great thing about assembly theory is we can actually measure how assembled a group of molecules is with
19:11 Neil deGrasse Tyson? Quantitatively.
19:12 Speaker 01 Actually with, yeah, quantitatively, we have predictions that we can make from the theory, but we can test them in the lab. And so we have a way of measuring the complexity of a molecule, independent of knowledge of what the molecule is. And we can just do it with a mass spectrometer.
19:26 Chuck Nice? Okay.
19:27 Neil deGrasse Tyson? See, this is, this is some, this is physics, badass physics coming in the doorway here. All right.
19:32 Speaker 01 We like measurements, they ground us in reality.
19:35 Neil deGrasse Tyson? Right. Evolutionary steps, sometimes we think of them that way, is, can involve added complexity. So why, what is, what are you doing that's different from that?
19:47 Speaker 01 So evolutionary theory is, we have it now, works really well for biology on Earth, but it doesn't help us understand life on other planets, or solve the origin of life, because we don't know where our life comes from to begin with, so we need
19:57 Neil deGrasse Tyson? Because you have a sample of one.
19:58 Speaker 01 Yeah, we have a sample of one, it's a big problem. We need a deeper explanation of evolution in order to explain how evolutionary systems that we recognize as biology emerge in the first place.
20:08 Chuck Nice? Is there any chance that it could just be a mistake?
20:12 Speaker 01 You know, that might be true, but then it's not very interesting from the perspective of theoretical physics, because there's nothing to explain.
20:19 Neil deGrasse Tyson? Okay, oh, good answer.
20:20 Chuck Nice? Yeah, I mean, it doesn't stop the search, though.
20:22 Speaker 01 No.
20:22 Chuck Nice? It's not, it's not very interesting at that point.
20:26 Neil deGrasse Tyson? All right, so let's make sure we're on the same page here. When I think of how a biologist would define life, which has been, there's been variations on that over the decades, but what comes to mind is, it's something that has a metabolism, so it uses energy from its environment, it reproduces and it evolves, in a Darwinian way.
20:48 Speaker 01 Yeah.
20:48 Neil deGrasse Tyson? You have Things to add to that, subtract from that?
20:53 Speaker 01 I don't-
20:54 Chuck Nice? Or can you juxtapose both? What do you use, what do you call what he just said in from your, where you are? What is that? And then where are you different?
21:03 Speaker 01 So, so one definition that people like to use, which encapsulates what you're saying as like fundamental pieces of it is life is a self-sustaining chemical system capable of Darwinian evolution. Quite a mouthful.
21:15 Chuck Nice? That is what he just said, though.
21:16 Speaker 01 Yeah, it is exactly.
21:19 Speaker 01 It truly is. So, you know, there's a lot of problems, actually, from my perspective with that definition. One of them is whether you regard life to be self-sustaining. So viruses are an example. People don't know whether to place them as life or not, because they're not self-sustaining on their own. And in fact, when we're doing, you know, chemical evolution in the laboratory, like trying to study molecules, you know, we don't know how to call them alive because they're not self-sustaining because graduate students are pipetting, you know, like they require the graduate student. So-
21:47 Neil deGrasse Tyson? Pipetting, that's a verb. Yeah. I know the pipetting. It's a little thing.
21:51 Speaker 01 Yeah.
21:52 Neil deGrasse Tyson? Yeah. Put a little glass straw in there. Yeah, yeah, so-
21:54 Speaker 01 Yeah, you gotta move, you gotta move the molecules from one tube to the next to do artificial selection.
21:58 Chuck Nice? So why do you say, "I am crushing your head"? No, okay, sorry.
22:01 Speaker 01 Right, so, so there's many, or, or my favorite example is like, you know, a parasite that, you know, sits in the, the, a brain of an ant and, you know, pilots the ant.
22:11 Chuck Nice? Right.
22:11 Speaker 01 Right? So I, I talk about that example in my book, actually.
22:14 Chuck Nice? I love that parasite, by the way.
22:15 Speaker 01 It's so crazy, but is that, is that a living, is that a life form? Because it's actually, you know, it's a symbiote, right? So, or actually a parasite. So this idea of self-sustaining is kind of very problematic for a lot of reasons. I don't actually think life is defined by chemistry. So this is, again, getting at deeper physical principles.
22:33 Chuck Nice? Wow.
22:34 Speaker 01 So I include technology. Yeah.
22:38 Neil deGrasse Tyson? First shots fired.
22:39 Speaker 01 Yeah. Yeah. So my definition, or well, my understanding of life, I don't have a definition. My understanding of life is life is the things that can only be produced by evolution and selection, and technology is also an example of that, and that's not chemical. And also this idea of it being self reproducing, I mean, there are plenty of humans that can't self reproduce, actually, no human can individually self reproduce.
23:00 Chuck Nice? Right. I've been trying.
23:02 Speaker 01 But there's plenty of things.
23:03 Chuck Nice? I've been trying.
23:06 Neil deGrasse Tyson? But, but, but a mule, for example.
23:08 Speaker 01 Yeah, exactly.
23:09 Neil deGrasse Tyson? Is certainly alive.
23:10 Speaker 01 Right.
23:11 Neil deGrasse Tyson? Can't reproduce.
23:11 Chuck Nice? Can't reproduce.
23:12 Speaker 01 Yeah, and those are, those are kind of odd examples because, because we bred them, but even if you think of like a bee in a colony, right, like most of the bees can't reproduce alone. Are they not alive?
23:20 Neil deGrasse Tyson? Right.
23:21 Speaker 01 Because they're part of a social network.
23:22 Neil deGrasse Tyson? Okay, so, so the traditional definition of life have issues.
23:25 Speaker 01 Lots of issues, every single word.
23:27 Neil deGrasse Tyson? Plus, there, there are stars that have metabolisms and they live out their lives and die, and then they explode and send their materials to other gas clouds that make other stars.
23:37 Chuck Nice? Right.
23:37 Neil deGrasse Tyson? They do reproduce.
23:38 Speaker 01 And there's some heritability there because of the elements that get made in one star generation.
23:42 Neil deGrasse Tyson? The DNA, one star goes into another.
23:43 Speaker 01 Yep, that's right.
23:43 Neil deGrasse Tyson? So are stars alive, right? We can ask that question.
23:46 Speaker 01 Yes, we could.
23:47 Neil deGrasse Tyson? So.
23:47 Speaker 01 Can ask any question.
23:49 Neil deGrasse Tyson? So why even have a definition at all?
23:52 Speaker 01 So I think definitions are useful heuristics in the absence of having a more fundamental understanding. And so one of my favorite sort of analogies that people in my field make is like, how would you define water before you knew atomic theory? You would describe it as like a clear liquid, it might, you know, be a liquid at room temperature, but you wouldn't really understand what water is until you understand what atoms are and how they combine to make H2O. And that's sort of where we are with definitions of life, we can kind of describe effectively its properties, but we don't have.
24:19 Neil deGrasse Tyson? Like a macroscopic.
24:20 Speaker 01 Yeah.
24:20 Chuck Nice? Yeah. You know what you're looking at. You know what you're looking at, you just don't know really what it is.
24:25 Speaker 01 Yeah, that's exactly right.
24:26 Chuck Nice? Right.
24:27 Speaker 01 And I want to know really what it is. I want to know at the same level that we understand our other theories of physics, like gravity or quantum mechanics.
24:34 Neil deGrasse Tyson? You have disentangled.
24:36 Speaker 01 Yeah.
24:36 Neil deGrasse Tyson? The definition of life.
24:37 Chuck Nice? Yeah.
24:38 Neil deGrasse Tyson? From people's biases.
24:40 Speaker 01 That's right.
24:40 Chuck Nice? Like a chef.
24:41 Speaker 01 Yeah.
24:41 Chuck Nice? Like when they talk.
24:42 Speaker 01 I'm cooking the primordial soup.
24:44 Neil deGrasse Tyson? When they deconstruct.
24:46 Chuck Nice? When they deconstruct the dish.
24:46 Neil deGrasse Tyson? Deconstruct the dish.
24:47 Chuck Nice? Yeah, you see all the, you're like, what the hell is that?
24:49 Neil deGrasse Tyson? I know, right? I had eggplant parmesan, the eggplant's here. The cheese over there. I said, dude, what am I paying you to do?
24:55 Chuck Nice? Exactly. The parmesan shows up on Tuesday.
24:59 Neil deGrasse Tyson? Alright, so, so let's get back to this. Any good theory?
25:06 Neil deGrasse Tyson? In fact, I'm a theory snob. Okay?
25:09 Speaker 01 Excellent. I love that. No, it's okay. I'm also a theory snob.
25:12 Neil deGrasse Tyson? No, no, theory snob.
25:13 Chuck Nice? Please, tell me about your theory.
25:14 Speaker 01 But I want to know what your definition of theory snob is, yeah?
25:16 Chuck Nice? I'm not sure that's a very good theory at all. No, that's not the kind of theory that we would let into this club. Yeah, yeah. Who sponsored you?
25:29 Chuck Nice? Sorry, I'm sorry.
25:31 Neil deGrasse Tyson? If you have an idea that you're still testing, then we should call it a hypothesis.
25:37 Neil deGrasse Tyson? And once it's tested and verified and supported by multiple people and not just your lab in the Beyond Institute or Beyond Center, then it can elevate to the level of a theory, which gives us the thermodynamics theory, quantum theory, relativity theory. But it's not Sarah's theory until it's multiply supported.
25:59 Speaker 01 Yes.
26:00 Neil deGrasse Tyson? I would call it Sarah's hypothesis and your colleague's, your hypothesis.
26:03 Chuck Nice? Ooh.
26:03 Neil deGrasse Tyson? Am I allowed? Will you grant me that?
26:05 Speaker 01 I'll grant you that. I think there are clear reasons why we called it a theory. And for me, what theories are, is our explanatory paradigms, like their actual frameworks that have brought explanatory paradigms.
26:14 Neil deGrasse Tyson? Predict something that we have found. Have you? What have you predicted that we have found?
26:18 Speaker 01 We have predicted that there should be a threshold above which only molecules produced by life should reside, and we've tested that experimentally.
26:26 Neil deGrasse Tyson? Wait, wait, wait, so I say?
26:27 Chuck Nice? I missed that.
26:29 Speaker 01 The universe can generate, you know, simple molecules. It can't generate complex molecules without evolution and selection. That suggests a boundary.
26:36 Neil deGrasse Tyson? This is the Lego experiment.
26:37 Speaker 01 Yes, a boundary that just random chemistry can explore, but it can't go beyond.
26:42 Neil deGrasse Tyson? Oh.
26:43 Speaker 01 And we've tested that with living and non-living samples, and even some that NASA sent, and this was done by Lee Cronin's lab. They sent him samples and they blinded them. And they tried to confuse, like, you know, blinded samples, one that you don't know the identity of the sample. And they tried to really trick them. They sent them Murchison meteorite, which is one of the most complex, inorganic, non-biological samples in the solar system. And it's still classified, the experimental approach still classified it correctly as non-living. And what we saw was only the living samples had. An assembly index value, this number of minimal steps above 15, which is not a magic number, it's just an experimentally confirmed number.
27:19 Neil deGrasse Tyson? So, so you're suggesting that nowhere in the universe, without some other driving force on the system, would give you a complexity higher than this?
27:28 Speaker 01 About 15, but that was for a specific set of chemical, like, kinds of bonds that can form, so we don't know if 15's a universal number, it might be different in a different planet with different geochemistry.
27:37 Chuck Nice? But the threshold is there, is, is the point.
27:39 Speaker 01 So that was the first prediction that we've made, that we've tested, and also the other thing that we have that hasn't come out yet is actually constructing phylogenetic trees.
27:47 Neil deGrasse Tyson? Hasn't been published yet.
27:48 Speaker 01 Hasn't been published yet, constructing phylogenetic trees with no genomic information, just molecular information.
27:53 Neil deGrasse Tyson? Taking that stuff down to molecules.
27:54 Speaker 01 Molecules, molecules contain their history.
27:57 Chuck Nice? Wow.
27:58 Speaker 01 But I think your point is really important about a theory, and obviously, like, this theory is still under development, but I think theories have played a really important role in the history of physics in terms of trying to unify a broad set of phenomena that we thought were different.
28:11 Neil deGrasse Tyson? I was just, initially, I would just call them hypothesis.
28:14 Speaker 01 Yeah, I think-
28:15 Neil deGrasse Tyson? That would then later be elevated to theory once it has been verified.
28:18 Chuck Nice? Yeah, you should kind of drop it down to hypothesis, because then when it's elevated, we can call it Sarah's theory.
28:23 Speaker 01 I don't want it to be called Sarah's theory, though.
28:25 Chuck Nice? What do you mean you don't want it to be called Sarah's theory?
28:28 Neil deGrasse Tyson? What it does is, speaking as, as an educator-
28:32 Speaker 01 Yeah.
28:33 Neil deGrasse Tyson? What it does is, it protects the usage of the word "theory" for things that are experimentally objectively true.
28:40 Chuck Nice? Right, right.
28:41 Neil deGrasse Tyson? Otherwise, you get people in Congress, I quote, "We should teach evolution only as a theory, and therefore teach other theories as well."
28:52 Chuck Nice? Evolution, oh-
28:53 Neil deGrasse Tyson? We were trying to get God in there.
28:55 Chuck Nice? Oh, God is.
28:56 Neil deGrasse Tyson? And so, so, which, we're susceptible.
28:58 Chuck Nice? Right.
28:59 Neil deGrasse Tyson? If a theory is something that's sort of in progress, and we don't, not really sure yet, and then it gets shown to be false, people will say, "Well, we're waiting for the day that relativity theory is shown to be false." That's not gonna happen.
29:10 Speaker 01 Yeah.
29:11 Neil deGrasse Tyson? Right?
29:12 Speaker 01 I know, I understand that, I think working from the scientist's side of it, it's really interesting, because I think also, I've noticed that, you know, distinguishing between a model and a theory is hard.
29:21 Neil deGrasse Tyson? That's another one, yeah.
29:22 Speaker 01 Yeah.
29:23 Neil deGrasse Tyson? Yeah, so these are, this is, on some level, it's semantic-
29:25 Speaker 01 Yeah.
29:26 Neil deGrasse Tyson? But it's semantic, just, it makes my job easier if we get the semantics right.
29:29 Speaker 01 We want your job to be easy.
29:31 Neil deGrasse Tyson? Don't mess with my So again, you're telling me left to its own devices, the universe can construct molecules of complexity level 15 in your units of complexity.
29:46 Speaker 01 Yes.
29:47 Neil deGrasse Tyson? Paradigm.
29:48 Speaker 01 Yes.
29:48 Neil deGrasse Tyson? Okay. After that, what does it require?
29:51 Speaker 01 It requires a system that has some constraints on what kind of molecules get produced.
29:57 Neil deGrasse Tyson? That favors one kind or another.
29:59 Speaker 01 Favors selection.
30:00 Chuck Nice? Selection.
30:01 Speaker 01 There's that word again.
30:01 Chuck Nice? We're back to that.
30:03 Neil deGrasse Tyson? Okay.
30:04 Chuck Nice? Gotcha.
30:04 Neil deGrasse Tyson? So.
30:06 Speaker 01 And memory.
30:07 Neil deGrasse Tyson? Whereas getting to a complexity level of 15 does not require that.
30:11 Speaker 01 That's right. And so a key component of passing that threshold is actually storing memory in the system because you have to remember the steps.
30:18 Neil deGrasse Tyson? So you can get to it every time?
30:19 Speaker 01 Mm hmm. That's right.
30:20 Neil deGrasse Tyson? Oh, otherwise it's just randomly getting.
30:22 Speaker 01 That's right.
30:22 Neil deGrasse Tyson? Oh, my gosh.
30:23 Chuck Nice? Yeah, that makes sense.
30:24 Neil deGrasse Tyson? Oh, yeah.
30:25 Chuck Nice? You have to know what not to do in order to know what to do.
30:28 Neil deGrasse Tyson? You're saying this meteorite and this meteorite can both get to complexity level 15 because they both formed in the void of the early universe, of the early solar system, but without a driving force.
30:39 Speaker 01 Yeah, without something to remember molecules that the meteorite has made in the past and then build further complexity on top of that, can't do it.
30:45 Neil deGrasse Tyson? So now you need some, you need a system to store information.
30:48 Speaker 01 That's right.
30:48 Neil deGrasse Tyson? And DNA can do that.
30:50 Speaker 01 Yes.
30:50 Neil deGrasse Tyson? Famously.
30:51 Speaker 01 Yes.
30:53 Chuck Nice? So is do, well, I guess there's no way to know. I was gonna say, is DNA, because like all of, everything around us, you know, that's organic, we all share this, right? So does, is that, is that optimized in any way for life? Do we look at that as a model that is optimized?
31:11 Neil deGrasse Tyson? I like that.
31:12 Speaker 01 Yeah.
31:13 Neil deGrasse Tyson? Because the, the Murchison meteorite doesn't contain living molecules.
31:17 Speaker 01 That's right. Yeah.
31:18 Neil deGrasse Tyson? So if you're gonna get what anyone would call life.
31:23 Neil deGrasse Tyson? Why doesn't it select the same path? Because this is a question that's come up. Uh, my colleagues in geology posed the question and I didn't have a good answer. It was an intriguing question. They look at multiple planets and they're finding the same rock. This comes directly out of what you're saying. They find the same rocks, even though it's a completely different planet.
31:45 Speaker 01 Yeah.
31:45 Neil deGrasse Tyson? Same rocks, that is, they understand the bio, the, the, the, the rocket chemistry of The composition, right. The composition and the like. There's basalt there, there's basalt here. Okay, that came out of a volcano. Volcanos here, volcanos there. Why can't life have the same consistency that geology does?
32:06 Speaker 01 It's, it's because of the complexity.
32:09 Neil deGrasse Tyson? Well, see, you have an answer for that.
32:10 Speaker 01 Yeah.
32:11 Neil deGrasse Tyson? You come out of your assembly theory with an answer to that.
32:13 Speaker 01 Yeah, yeah, that's right.
32:15 Neil deGrasse Tyson? Can you assemble something like DNA that isn't DNA? That would be?
32:18 Speaker 01 Yes.
32:19 Neil deGrasse Tyson? That would, oh, oh, oh, whoa! Watch out! Hello! Okay. Oh, I'm sorry. You buried the lead! Okay.
32:28 Speaker 01 Sorry.
32:28 Neil deGrasse Tyson? Oh, my God! Okay, I'm sorry. All right, all right, so, so. That's amazing. What, pray tell, can store information for you? And? And go beyond your 15 steps? And do you have this thing locked up? That's it. That is what I'm.
32:43 Speaker 01 I have to say, I'm a serious, non-experimentalist, so I haven't built these things myself, but there, I mean, even
32:48 Neil deGrasse Tyson? But, but.
32:48 Speaker 01 Even in the space of just synthetic biology, people have alternatives to DNA and RNA, which are the usual.
32:54 Neil deGrasse Tyson? Let me just remind people, synthetic biology is basically genetically modified organisms. Right. Right, that's what that is. It's got this new branding, but it's, that's what.
33:02 Speaker 01 Yeah.
33:03 Neil deGrasse Tyson? It's start, we started out thinking about it as GMOs. Because nobody wants to say genetically modified. Yeah, so synthetic biology.
33:10 Speaker 01 Yeah, so there's all kinds of different, they're, they're called XNAs, like, you know, alternative nucleic acids, basically, that people have studied. So, so those are real molecules that people have validated in the lab and actually work in living cells. But what we're trying to get at, that's a bit deeper than that with assembly theory, is actually looking at the iteration of chemical space and trying to predict what molecules could be. And right now, where we're doing that most significantly is for drug design.
33:34 Neil deGrasse Tyson? That makes sense.
33:35 Speaker 01 And predicting pharmaceutical drugs. And there are, there are some approaches also, if you're talking about validation of a theory. There are some places where we've able, been able to predict molecules and actually synthesize them. And then
33:47 Neil deGrasse Tyson? Knowing that they be stable.
33:48 Speaker 01 Yeah. So for example, one place is really interesting is looking at non-addictive opioids. So if you want to make an opioid, you want to keep the opioid groups like that, those parts of the molecule and then make it non-addictive, you actually have to look at molecules that are not addictive and then try to combine their features.
34:01 Chuck Nice? Or you get them together and then you figure out how you make the non-addictive molecule bind in such a way that you get the result of the opioid without.
34:10 Speaker 01 Yep. So you can look at the steps to making both kinds of molecules and then you can combine those steps to look at other kinds of molecules.
34:15 Chuck Nice? Freaking crazy.
34:16 Neil deGrasse Tyson? Okay, so, so how, so.
34:18 Speaker 01 This is what solving alien life will give you, new drugs.
34:20 Neil deGrasse Tyson? We're gonna get to aliens in a minute.
34:24 Chuck Nice? Let me tell you something.
34:25 Neil deGrasse Tyson? That's good.
34:26 Chuck Nice? Make sure you lead with that when you're going for your grants.
34:30 Speaker 01 It is part of the strategy, actually.
34:32 Chuck Nice? It's a good one.
34:34 Neil deGrasse Tyson? How do molecules behave? So give me an example of something that can encode, store information that is not DNA.
34:42 Speaker 01 Well, you can store information in RNA and protein, those are already in cells. But there's one I like is, and I actually don't know if people have stored information in it, it's called PNA, it's peptide nucleic acid. I like that because it's kind of a cross between a protein and DNA.
34:56 Neil deGrasse Tyson? Right. All right.
34:58 Speaker 01 And so, so most of the places where people have studied these kind of alternative nucleic acids is just, you know, in synthetic biology labs. But there, there's a whole host of them that you could use. Just the same way that you can store information in DNA, you could just write a sequence of bases in one of these kind of molecules. Minerals are more fun though, trying to store information in a mineral is pretty crazy.
35:17 Chuck Nice? Whoa. So, okay, that's pretty wild. Now, uh, why would you be storing information in the mineral?
35:24 Speaker 01 Minerals are really important in origin of life chemistry and we think that they were actually the first templates for information to actually pattern chemistry in specific ways and they retain, you know, they have an aperiodic pattern to them, which means they can contain a lot of information.
35:37 Neil deGrasse Tyson? And they actually. Because it was perfectly periodic.
35:38 Speaker 01 Yep.
35:39 Neil deGrasse Tyson? There's hardly any information.
35:40 Speaker 01 That's right.
35:40 Neil deGrasse Tyson? Right.
35:41 Speaker 01 Yeah, so this goes all the way back to.
35:43 Neil deGrasse Tyson? Has hardly any information.
35:44 Speaker 01 Right.
35:44 Neil deGrasse Tyson? Because everything is regular.
35:45 Speaker 01 Yeah.
35:46 Neil deGrasse Tyson? Right, so if you, if it varies but then repeats, you can stick something in there.
35:52 Chuck Nice? Right.
35:52 Neil deGrasse Tyson? And repeat it and remember it.
35:54 Speaker 01 Yes.
35:54 Neil deGrasse Tyson? Okay.
35:55 Chuck Nice? Fascinating.
35:56 Speaker 01 Yeah, so, so minerals might have been the templates for the first genetic information, actually.
36:00 Chuck Nice? Gotcha, gotcha.
36:17 Neil deGrasse Tyson? So now we want to look for aliens.
36:19 Speaker 01 Mm-hmm.
36:20 Neil deGrasse Tyson? How did what you do inform that?
36:22 Speaker 01 So, the, the current way that we're informing it, I think that's most significant, is this ability to look for complexity in the universe as a biosignature, instead of looking for specific molecules that life on Earth generated. And we can do that with a mass spectrometer, so we can just, you know, fly to another body in our solar system and try to infer whether there's high-assembly molecules there.
36:43 Chuck Nice? Right.
36:43 Neil deGrasse Tyson? Whether or not it's crawling out of a beaker.
36:45 Chuck Nice? Doesn't make a difference.
36:46 Neil deGrasse Tyson? Or...
36:47 Speaker 01 Well, we haven't seen that yet, so, and we haven't seen little critters crawling around on, you know, Enceladus's plumes, or on Mars, or anything, so I think we need, we need better tools.
36:55 Neil deGrasse Tyson? In your universe of complexity, it is a measure of the complexity of information, and artificial intelligence is a level of complexity that's even beyond biologic, what we think of as biological. How do you rate artificial intelligence, as it's currently expressed in our world, on your scale of...
37:20 Speaker 01 So, I definitely think artificial intelligence is life, but I also, I know, shocking, huh? Shocking! But I also think your microphone...
37:27 Chuck Nice? Why was I programmed to feel pain?
37:28 Speaker 01 Oh, did you feel pain from that? I'm so sorry, I didn't mean to induce pain. Um, often, you know, like, yeah, there's a lot of shock value to things I say, so I guess I induce pain.
37:37 Chuck Nice? That's a very shocking statement.
37:39 Neil deGrasse Tyson? Why? Why do you feel that way, though?
37:41 Speaker 01 Well, so, I think you want to make a distinction between what you might call life and what you might call alive, and this actually comes derived from the theory, and the way I've been thinking about life for a long time, so, the things I would qualify as life are anything that requires evolution and selection to produce them, and artificial intelligence do not exist on a planet unless there are billions of years of evolution to make intelligent beings like us that are capable of engineering them. So, in that sense, they are life.
38:03 Neil deGrasse Tyson? But your universe is not creating AI.
38:04 Speaker 01 No. There are no large language models on Mars unless we put them there.
38:07 Neil deGrasse Tyson? Interesting. So, therefore...
38:09 Speaker 01 Yeah.
38:10 Neil deGrasse Tyson? We are the remembered molecular complexity...
38:13 Speaker 01 Yes.
38:13 Neil deGrasse Tyson? ...to create that.
38:14 Speaker 01 Yes, we're like the minerals imprinting on the genomic information of AI.
38:17 Chuck Nice? That makes sense, I gotta say, I didn't want to actually agree with this, but now I'm thinking of, perhaps, in a world, maybe even our own, where we're a couple hundred years in the future, or we have somehow... mucked things up to the point where we're not going to be here. So we then turn to artificial intelligence, imprint it with the ability to do everything that we do. It continues to evolve in our absence.
38:42 Speaker 01 Mm hmm.
38:42 Chuck Nice? And then somebody comes and finds us, but not this organic life. It finds us in the form of what we left behind, which was artificial intelligence.
38:52 Neil deGrasse Tyson? Okay, what have you been smoking before?
38:54 Speaker 01 I have a more optimistic view of it though.
38:56 Chuck Nice? I did create a whole story out of that, and it wasn't very optimistic.
38:59 Speaker 01 Yeah, I think, I think when people envision that future, they don't envision us still being here. But, you know, like, cells are inside our bodies and part of like the evolutionary structure we are. They've been here for billions of years. I don't think artificial intelligence or our technology is going to replace us. It's going to become part of a larger integrated system of technology and biology that's co-evolving on the planet.
39:17 Chuck Nice? I agree with that as a beginning, but I think unfortunately, our nature is our penchant and proclivity for self-destruction, which will leave artificial intelligence behind.
39:29 Speaker 01 You're a glasses half-empty, I'm a glasses half-full kind of person.
39:32 Neil deGrasse Tyson? Let's take it to the next level.
39:34 Speaker 01 Yeah.
39:34 Neil deGrasse Tyson? Okay. Go ahead. Actually, I have the answer to the half-empty, half-full question.
39:38 Speaker 01 Excellent.
39:38 Chuck Nice? Yeah. Drink it.
39:41 Speaker 01 What is the answer? That's a profound question.
39:42 Neil deGrasse Tyson? No, no, no, to me, it's no longer profound. If you have a vessel.
39:45 Chuck Nice? Uh huh.
39:46 Neil deGrasse Tyson? And you're adding liquid to it.
39:47 Chuck Nice? Right.
39:48 Neil deGrasse Tyson? And it reaches the halfway point, it's half-full. If you have a vessel.
39:51 Speaker 01 Oh, you have to know the mechanism, I see.
39:53 Chuck Nice? It's half-empty.
39:54 Neil deGrasse Tyson? It's half-empty.
39:54 Chuck Nice? So it depends on where you start.
39:56 Neil deGrasse Tyson? No, it depends, the rate of change, or it's the like, in calculus, it'd be the first derivative of the volume of liquid that's in it.
40:03 Chuck Nice? Right.
40:03 Neil deGrasse Tyson? Is that positive or negative? And then it's half-full or half-empty.
40:06 Speaker 01 History matters.
40:07 Neil deGrasse Tyson? Yes, yes, exactly.
40:08 Speaker 01 It's very assembly theoretic and very evolved.
40:10 Chuck Nice? Wow. See, I just got a compliment.
40:13 Neil deGrasse Tyson? You did.
40:13 Chuck Nice? Don't worry, I caught the compliment.
40:15 Neil deGrasse Tyson? Okay, all right. So let's take it up a notch.
40:18 Speaker 01 Mm hmm.
40:18 Neil deGrasse Tyson? If we are all simulated by some alien juvenile in a basement.
40:23 Speaker 01 Yeah.
40:24 Neil deGrasse Tyson? Uh, well, they just simulated you to think and say that.
40:29 Speaker 01 Sure.
40:29 Chuck Nice? In that full-up variant. Or simulated a surrounding where it would lead you to say that, even you being sentient and capable of making deducts.
40:37 Neil deGrasse Tyson? That's right.
40:37 Speaker 01 A simulation would say something like that.
40:39 Neil deGrasse Tyson? Oh, it's exactly what you would say, so.
40:43 Chuck Nice? That was very good.
40:44 Neil deGrasse Tyson? That was good. So a simulation is zeros and ones on a chip, creating information that's stored in zeros and ones and manipulated and maneuvered. Is that alive?
41:02 Speaker 01 So simulation-
41:04 Neil deGrasse Tyson? Are you alive in a simulation?
41:05 Chuck Nice? Oh.
41:06 Speaker 01 I don't think that we're living in a simulation. And the sort of key evidence there is you just talked about the simulation having to run in a chip, which means it needs a physical hardware. And there is always under, there's always a physical substrate underlying any simulation that, as far as we understand, so there's always a physical reality at the bottom.
41:22 Neil deGrasse Tyson? Why isn't the simulation empowering you to discover molecules that comprise your body?
41:29 Speaker 01 It does, it does actually, because you can have AI-driven exploration of chemical space, for example. So that's a clear place where a simulation is driving exploration and making things physical that aren't physical in the absence of a simulation.
41:41 Neil deGrasse Tyson? Exactly, because we joke about, what we talk about. If, if this whole world is simulated, it would be really inefficient to simulate parts that no sentient being is absorbing at any given moment. So you'd only simulate where you need to simulate.
41:56 Chuck Nice? What is necessary at the time that it's needed.
41:58 Neil deGrasse Tyson? If I want to dig to the center of the earth-
42:00 Chuck Nice? I don't need to make it until I'm digging to the center of the earth.
42:04 Neil deGrasse Tyson? And you simulate it as I'm doing it. And so the simulation is creating the molecules that I'm measuring as having complexity.
42:12 Speaker 01 I think we see observational evidence of that and just with our technologies. And I think that's really important. And I think there it's explanatory, but when you say the universe is a simulation, I don't think it gives you any additional explanatory power. I find it to be a useless hypothesis.
42:27 Chuck Nice? Well, that's, I know what you're saying, because then everything is resi, it's like I say-
42:32 Neil deGrasse Tyson? She just called me useless.
42:33 Speaker 01 No.
42:34 Chuck Nice? No.
42:34 Neil deGrasse Tyson? I'm just kidding.
42:35 Chuck Nice? No, what I say to that is it doesn't make a difference, because at the end of the week, I still owe Visa, you know, $210. So what difference does it make if, if the whole universe is a simulation? If at the end of the week, I still owe Visa $210?
42:48 Speaker 01 And you can still write down like laws of physics that describe your universe.
42:51 Chuck Nice? No, that's what I'm saying. It doesn't make a difference. It's all the same.
42:53 Neil deGrasse Tyson? Oh, I understand.
42:54 Chuck Nice? You know?
42:55 Neil deGrasse Tyson? You're saying the distinction is not interesting if you can't make the distinction.
43:01 Speaker 01 That's right. So I think simulations being an emergent property that the universe creates, the one that happens through evolution, is interesting. And then asking about the physical nature of simulations and why life generates them. That's interesting. Saying the universe is a simulation kicks the can way too far back for me to give any explanatory power to what we're talking about.
43:18 Chuck Nice? Ah, so because you can't figure it out, it don't mean nothing.
43:21 Speaker 01 That's exactly right. Don't you know you're in a room with theoretical physicists?
43:27 Speaker 01 That's exactly like, that's my card.
43:30 Neil deGrasse Tyson? We'll grant you your complexity.
43:32 Speaker 01 Okay.
43:32 Neil deGrasse Tyson? In your assembly theory.
43:33 Speaker 01 Thank you.
43:34 Neil deGrasse Tyson? How metanatamous of you.
43:36 Speaker 01 I know.
43:39 Neil deGrasse Tyson? We granted, StarTalk grants you.
43:44 Speaker 01 Do I get a badge for this or something?
43:45 Neil deGrasse Tyson? I will find something here, it on your hair. So.
43:49 Speaker 01 Or I'm like knighted.
43:51 Neil deGrasse Tyson? So. In that, does it say anything about free will? We've had a few episodes on that subject. With some leading thinkers in the area. Indeed. What, can you say anything about it?
44:06 Speaker 01 Yeah, I have a lot to say on it, but I think the sort of most important thing is I think you can have free will and be consistent with the laws of physics as we understand them. And the reason for that.
44:17 Neil deGrasse Tyson? You can have free will.
44:17 Speaker 01 You can.
44:18 Neil deGrasse Tyson? Because people were arguing that you couldn't.
44:20 Speaker 01 Yes.
44:20 Neil deGrasse Tyson? Because the laws of physics are commanding everything you say they can do.
44:23 Speaker 01 That's right. That's right.
44:24 Neil deGrasse Tyson? Yeah.
44:24 Speaker 01 And then the flip side of it is like, you know, the universe is totally random and then you have absolute freedom, right? So it's not that you have total, um, or, you know, free will is a trade off between the sort of control and the freedom. And I think what happens is when you have these evolved structures that are building complexity, they become really constrained by their history, but they still have some freedom in terms of the kind of complexity they can generate. And so, um, and, and this becomes sort of deeply intrinsic to what they are. So they are deterministic in some sense, but there's still some freedom for them to actually make action.
44:57 Neil deGrasse Tyson? Normally when we think of free will, we think of I'm deciding. Right. But really, if you come at from a molecular point of view, it's whatever the molecule is going to make. And it will work within the space of options it has available.
45:10 Speaker 01 Yeah, free will is executed over time, right? So this is also the thing, it's not instantaneous. We don't have free will to be in Arizona right now.
45:16 Neil deGrasse Tyson? Right.
45:16 Speaker 01 But we could be there tomorrow.
45:18 Neil deGrasse Tyson? Right.
45:18 Speaker 01 So I think this, you know, a key point that we're missing is it's not like you have instantaneous command over what the atoms in your bottom are doing, but you can make decisions over time.
45:27 Chuck Nice? And even your decisions are determined by what came before. So they're executed over a period of time.
45:33 Speaker 01 Yes.
45:33 Chuck Nice? Just the fact that, you know, well, I'm a comedian. Well, I didn't just wake up one day and go, I'm a comedian.
45:39 Neil deGrasse Tyson? It has precedent.
45:40 Chuck Nice? It has precedent, right.
45:41 Speaker 01 Yeah, assembly theory makes some really radical conjectures about like the future being larger than the past. And so there's also some freedom in terms of, because of this idea of building complexity, the future is always more complex and larger and sort of the space of possibilities.
45:54 Chuck Nice? Because it's not here, though.
45:56 Speaker 01 Yes.
45:57 Neil deGrasse Tyson? I get this, and it helps that we have an expanding universe.
46:00 Speaker 01 Yes, it does. Exactly. No, this is exactly right. The universe is getting bigger every minute.
46:04 Neil deGrasse Tyson? To accommodate.
46:05 Chuck Nice? Exactly.
46:06 Neil deGrasse Tyson? This.
46:06 Chuck Nice? Cool.
46:07 Neil deGrasse Tyson? What does this say about entropy?
46:09 Speaker 01 So, yeah.
46:11 Chuck Nice? Oh.
46:11 Neil deGrasse Tyson? Entropy requires.
46:12 Chuck Nice? Oh, I want to hear this.
46:13 Speaker 01 You're not gonna let.
46:14 Chuck Nice? Hold on, hold on.
46:15 Neil deGrasse Tyson? He's got his popcorn out.
46:16 Chuck Nice? Let me get my popcorn out. He's gonna, after all that we've been through, we got to entropy now?
46:20 Neil deGrasse Tyson? Entropy wants disorder as a, as a, as a direction in which systems move.
46:28 Speaker 01 That's right.
46:28 Neil deGrasse Tyson? All right.
46:29 Speaker 01 So, but the, the reason that that hap, like we describe things that way is because of the way we label states. Like entropy depends on a couple of key features. One is like you as an observer labeling the particular configurations. And the other one, being able to talk about an ensemble of systems that are identically prepared and there's some statistical trend. And what is happening in the biosphere is complexity is increasing. It's kind of like an entropic tendency, but it's actually over configurations, like the combinatorial space. And so I don't really actually think the second law is telling us that things are.
47:03 Neil deGrasse Tyson? Thermodynamics.
47:04 Speaker 01 Yeah, second law of thermodynamics is necessarily telling us that things are trending toward disorder. I think there's a deeper law underlying that that can also account for the structure of what we see in life.
47:15 Neil deGrasse Tyson? But.
47:16 Speaker 01 Of course, there's still entropy, you know.
47:18 Neil deGrasse Tyson? Typical physics would say.
47:20 Speaker 01 Yeah.
47:20 Neil deGrasse Tyson? We're getting, it's only for closed systems that you.
47:23 Speaker 01 Yes.
47:23 Neil deGrasse Tyson? Evolve towards.
47:24 Speaker 01 Yes.
47:24 Neil deGrasse Tyson? A higher.
47:26 Speaker 01 But of course, the universe might be an open system.
47:29 Neil deGrasse Tyson? No, no, but I'm saying, but Earth is clearly not a closed system.
47:31 Speaker 01 That's right.
47:31 Neil deGrasse Tyson? We have sunlight coming in.
47:33 Speaker 01 That's right.
47:33 Neil deGrasse Tyson? And, and so we've credited that infusion of energy as a pump for the development of complexity.
47:41 Speaker 01 Yes.
47:42 Neil deGrasse Tyson? That wouldn't otherwise be there. Right, like if there were no sun, none of this crap would be here.
47:47 Speaker 01 One of the things that's been really hard from the perspective of, of theoretical physics as it's written now, not like what new laws might be present in biology to explain, is that it looks like the, what life is doing is changing the nature of the underlying state space as, as we talk about it in physics as it's going along. So it's hard to define something like entropy when you can't count the same things at every instance in time.
48:09 Neil deGrasse Tyson? So you, you want, you want a second and a half law of thermodynamics?
48:17 Neil deGrasse Tyson? That applies to the observed universe?
48:19 Speaker 01 The second law of thermodynamics is an approximate law. I think we, we all know this is statistical statement. I would like an exact law.
48:25 Neil deGrasse Tyson? Ooh. Wow, you are very demanding, I gotta tell you.
48:30 Neil deGrasse Tyson? You are not messing around.
48:31 Speaker 01 Yeah. Theoretical physicists don't mess around.
48:35 Neil deGrasse Tyson? Wow, okay. Screw you, Newton.
48:38 Speaker 01 It's all his fault.
48:40 Neil deGrasse Tyson? And you put all of this in a book. In a book? Oh my gosh. Life as no one knows it. Except for you.
48:52 Speaker 01 Uh, I still don't know it either. I'm still one of the no ones.
48:56 Neil deGrasse Tyson? I love it. Life as no one, including the author, but it's the whole foundations of that thinking.
49:01 Speaker 01 Yes.
49:01 Neil deGrasse Tyson? And, and I'm glad it doesn't just live in this conversation. Yeah. Cause it lives in the pages of this book. So this came out just recently.
49:10 Speaker 01 That's right.
49:11 Neil deGrasse Tyson? Just summer 2024. Oh, good for you. Yeah, yeah. Congratulations.
49:16 Speaker 01 Thank you.
49:16 Neil deGrasse Tyson? Congratulations, your first book?
49:18 Speaker 01 It is my first book.
49:18 Neil deGrasse Tyson? Excellent. Wonderful. Excellent. And at the rate you're going, more books? Are you kidding me? We just wrote one today. We wrote one just now.
49:29 Neil deGrasse Tyson? No, so I would look, look forward to what becomes of this branch of thinking.
49:35 Speaker 01 I'm hoping we will do an experiment where an alien crawls out of it.
49:40 Neil deGrasse Tyson? I'm gonna say I'm not with you.
49:44 Chuck Nice? Just gonna go on the record and say no.
49:47 Neil deGrasse Tyson? You don't want the alien crawling out.
49:48 Chuck Nice? No, thank you.
49:49 Neil deGrasse Tyson? Nothing crawling out of anything.
49:52 Speaker 01 But the understanding that would come with that would be so great.
49:54 Chuck Nice? Yeah, that's right.
49:55 Neil deGrasse Tyson? That's a pure scientist saying, but we'll learn. Exactly. You know? Right. I think there's a famous quote from Kurt Vonnegut who says, "The last word ever spoken by any human is between two scientists." And one says to the other, "Let's try the experiment the other way."
50:14 Neil deGrasse Tyson? There you go. That's it. That makes perfect sense. You're all excited about it. It's the last word. It's the last word spoken. Yeah, it's gonna be you.
50:22 Speaker 01 I'm a theorist. I'm not doing the experiment.
50:27 Speaker 01 See, this is another reason to be a theorist. Yeah, you don't have to do the last experiment.
50:31 Neil deGrasse Tyson? All right. Well, this has been a delight. Thank you for sharing your expertise and your wisdom and your knowledge coming from beyond.
50:37 Speaker 01 Literally.
50:38 Neil deGrasse Tyson? Beyond. Yeah, I saw what you did there. Yeah. Yeah, that was cool. Yeah, very, very good. And you gotta keep us appraised. Yeah. Of new development. Fascinating frontier. I gotta give it to you. And, and do you, do you have a pipeline into NASA as they set up experiments to look for life? Cause we just had Funky Spoon. Dr. Funky, David Grin spoon.
50:57 Speaker 01 Oh, I love David. He's great.
50:58 Neil deGrasse Tyson? David Grin spoon. We just had him a few days ago.
51:00 Speaker 01 Oh, really?
51:00 Neil deGrasse Tyson? Yeah. And so he's guiding NASA's search for life. And if you have something to tell him, you should, you better tell him quick.
51:07 Speaker 01 Yeah, I could tell him, but actually what I'm trying to do now is prepare data. Because when you're talking about artificial intelligence, people are also trying to use it for life detection. And we don't have good data to train models on.
51:16 Neil deGrasse Tyson? Right. Right. It's not like a large language model for aliens.
51:19 Speaker 01 That's right. We don't have one.
51:20 Neil deGrasse Tyson? Right, right, right. Awesome. All right. That's a lot of fun. Thanks. That was great. Let me, let me see if I can put some cosmic perspective on this. On this? Yeah. Yeah, yeah. Always throughout time, throughout the history of civilization, somebody had to think out of the box. Somebody does it first. And they always look a little weird to everybody else. They look a little strange. And most people who do that are just wrong. Let's be honest about this. There's a trash bin of people who stepped out of the box, thinking they had new insights into the nature of reality, and they did not. So how do you find the ones that work?
52:03 Neil deGrasse Tyson? That move where we all are and how we think? It needs to be subject to experiment and observation. It can't just live in your head and make sense to you and no one else. So for me, watching these new steps to think about life, to bring a little bit of dose of physics, theoretical physics into the equation, to me, is an important first step. And I look forward to where this will take us. Just short of the alien falling out of the box. Don't stop short of the possibility that the alien can help save us from ourselves. That is a cosmic perspective.
52:46 Neil deGrasse Tyson? This has been another episode of StarTalk, taking you to places that we hadn't been the day before. Yeah. Sarah, Dwight, thank you.
52:54 Speaker 01 Thank you, guys.
52:55 Neil deGrasse Tyson? Thanks for coming to my office here at the Hayden Planetarium.
52:58 Speaker 01 It was really fun.
52:59 Neil deGrasse Tyson? In New York City, the American Museum of Natural History. All of you are from Arizona.
53:03 Speaker 01 Yes.
53:03 Neil deGrasse Tyson? So tell folks at ASU I said hi.
53:06 Speaker 01 I will.
53:06 Neil deGrasse Tyson? We love them all down there, in the heat. Do you know Tempe, Arizona, is one quarter of a mile from the surface of the sun? Did you? Yeah, that's funny.
53:15 Speaker 01 I knew that.
53:15 Neil deGrasse Tyson? That's an old joke. It hit 120 degrees this past summer, right?
53:20 Speaker 01 Yeah, that's typical.
53:22 Neil deGrasse Tyson? Yeah, oh, yeah, yeah, all right.
53:23 Speaker 01 Sometimes we can't even fly planes, it's so hot.
53:25 Neil deGrasse Tyson? Oh, because there's not enough air density coming through the thing.
53:28 Speaker 01 That's right.
53:28 Neil deGrasse Tyson? Wow.
53:28 Speaker 01 There's some good physics for you.
53:29 Neil deGrasse Tyson? Yeah, yeah, it's not just the temperatures, the density of the air. Right, yeah. Or you need a longer runway or something. Yeah, yeah. We got to call it quits there. Chuck, always good to have you, man. Always a pleasure. And again.
53:40 Speaker 01 Thank you so much.
53:41 Neil deGrasse Tyson? My congratulations and good luck on life as no one knows it, not even the author. That's what makes this especially intriguing.
53:49 Speaker 01 Hopefully, someone will know it one day.
53:51 Neil deGrasse Tyson? One day, one day. All right, StarTalk here, keep looking up.
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