#279 – Alien Debate: Sara Walker and Lee Cronin

Sara Walker is an astrobiologist and theoretical physicist. Lee Cronin is a chemist. This is a conversation and debate about alien life and alien civilizations. Please support this podcast by checking out our sponsors: – Uncruise: https://uncruise.com/pages/lex – Linode: https://linode.com/lex to get $100 free credit – ExpressVPN: https://expressvpn.com/lexpod and use code LexPod to get 3 months free – ROKA: https://roka.com/ and use code LEX to get 20% off your first order – Athletic Greens: https://athleticgreens.com/lex and use code LEX to get 1 month of fish oil EPISODE LINKS: Sara’s Twitter: https://twitter.com/Sara_Imari Sara’s Website: http://emergence.asu.edu Lee’s Twitter: https://twitter.com/leecronin Lee’s Website: https://www.chem.gla.ac.uk/cronin Chemify’s Website: https://chemify.io PODCAST INFO: Podcast website: https://lexfridman.com/podcast Apple Podcasts: https://apple.co/2lwqZIr Spotify: https://spoti.fi/2nEwCF8 RSS: https://lexfridman.com/feed/podcast/ YouTube Full Episodes: https://youtube.com/lexfridman YouTube Clips: https://youtube.com/lexclips SUPPORT & CONNECT: – Check out the sponsors above, it’s the best way to support this podcast – Support on Patreon: https://www.patreon.com/lexfridman – Twitter: https://twitter.com/lexfridman – Instagram: https://www.instagram.com/lexfridman – LinkedIn: https://www.linkedin.com/in/lexfridman – Facebook: https://www.facebook.com/lexfridman – Medium: https://medium.com/@lexfridman OUTLINE: Here’s the timestamps for the episode. On some podcast players you should be able to click the timestamp to jump to that time. (00:00) – Introduction (07:47) – Aliens (21:53) – What is life? (29:35) – Assembly theory (52:03) – Math (1:03:45) – Communication with aliens (1:28:38) – Evolution of the universe (1:37:56) – Creating alien life (1:45:29) – Origin of life (1:52:29) – Before the Big Bang (1:59:22) – God (2:09:39) – Goal-directed behavior (2:27:37) – Time (2:35:54) – Free will and imagination (2:51:06) – UFO sightings (2:56:06) – Alien life forms debate (3:11:14) – Robots (3:20:29) – Love and emotion (3:38:55) – Beauty in science (3:49:06) – Random questions (3:58:30) – Advice for young people (4:01:48) – Life on Earth (4:06:12) – Memory

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Lex Fridman?

  The following is a conversation with Sarah Walker and Lee Cronin. They have each been on this podcast once before individually, and now, for their second time, they're here together. Sarah is an astrobiologist and theoretical physicist. Lee is a chemist, and, if I may say so, the real-life manifestation of Rick from Rick and Morty. They both are interested in how life originates and develops, both life here on Earth and alien life, including intelligent alien civilizations out there in the cosmos. They are colleagues and friends who love to explore, disagree, and debate nuanced points about alien life, and so, we're calling this "An Alien Debate."

• 0:45Lex Fridman?

  Very few questions to me are as fascinating as what do aliens look like? How do we recognize them? How do we talk to them? And how do we make sense of life here on Earth in the context of all possible life forms that are out there? Treating these questions with the seriousness and rigor they deserve is what I hope to do with this conversation and future ones like it. Our world is shrouded in mystery. We must first be humble to acknowledge this, and then be bold in diving in and trying to figure things out, anyway.

• 1:19Lex Fridman?

  And now, a quick few-second mention of each sponsor. Check them out in the description. It's the best way to support this podcast. We've got Uncruise for adventure, Linode for cloud computing, ExpressVPN for privacy, Roka for style, and Athletic Greens for performance. Choose wisely, my friends. And now, onto the full ad reads. As always, no ads in the middle. I try to make this interesting, but if you skip them, please still check out the sponsors. I enjoy their stuff. Maybe you will, too.

• 1:49Lex Fridman?

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• 2:09Lex Fridman?

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• 2:56Lex Fridman?

  This episode is also brought to you by Linode, Linux virtual machines. It's an awesome compute infrastructure that lets you develop, deploy and scale what applications you build faster and easier. This is both for small personal projects and huge systems. Lower cost than AWS, but more important to me is the simplicity quality of the customer service with real humans. 24/7/365. I can't tell you, first of all, how much I love Linux and how much I love cloud services that provide that infrastructure and make it super easy to manage it, to monitor it, to scale things up, to make many copies of it. I mean, just to run your computer infrastructure.

• 3:41Lex Fridman?

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• 4:07Lex Fridman?

  This episode is also brought to you by ExpressVPN. I use them to protect my privacy on the interwebs. I've used them for many, many, many years. I love ExpressVPN. The big red sexy button just makes my heart sing. There's a lot of reasons you want to use a VPN, ExpressVPN being the best one. First of all, ISPs are still collecting your data, internet service providers. It doesn't matter if you're using Chrome incognito mode, they can still see all the shady stuff you do on the internet. Second, you can change the location if you watch different shows on Netflix and Hulu and so on, change geographic location in a split second. And it unlocks those parts of those platforms.

• 4:49Lex Fridman?

  To me, the most important thing is that ExpressVPN just works. It's fast, whatever device you got, whatever operating system, including my favorite, of course, Linux, it works and it works wonderfully. It does a simple job and it does it well. Go to expressvpn.com/lexpod to get an extra three months free. That's expressvpn.com/lexpod. This show is also brought to you by Roka, the makers of glasses and sunglasses that I love wearing for their design, feel, and innovation on material optics and grip. Roka was started by two all-American swimmers from Stanford and was born out of an obsession with performance.

• 5:31Lex Fridman?

  I met one of those founders, Rob, and he's an awesome human being. They have a place here in Austin, but more than the place, the people, both brilliant and passionate, and they know what they want to do, which is design a stylish eyewear. I was, actually did a long run today and I wore the shades. Part of the reason I actually wore the shades, it wasn't even that sunny, is I want to kind of escape from the world. I want to hide myself from the world. Sometimes I just want to hide away. It's the introvert in me. I was listening to a good audiobook and I wanted to hide away and look good while doing it, which is why I wore Roka sunglasses. Check them out for both prescription glasses and sunglasses at roka.com and enter code

• 6:16Lex Fridman?

  Lex to save 20% off on your first order. That's roka.com and enter code Lex. This show is also brought to you by Athletic Greens and its newly renamed AG1 Drink, which is an all-in-one daily drink to support better health and peak performance. It replaced the multivitamin for me and went far beyond that with 75 vitamins and minerals. It's the first thing I drink every day. I drink it twice a day now. It brings my heart joy. The joy part might be a placebo effect, I don't know, but the fact of the matter is I do some crazy stuff in terms of physical and mental undertakings. I also fast often.

• 6:56Lex Fridman?

  I do keto diets. I do carnivore. I do all kinds of crazy stuff and I can count on Athletic Greens to provide the nutritional basis that frees me to do the crazy stuff I do. That's freedom. It's having that nutritional foundation. They'll give you one month's supply of fish oil when you sign up to athleticgreens.com/lex. That's athleticgreens.com/lex. This is the Lex Fridman Podcast and here is my conversation with Sarah Walker and Lee Cronin.

• 7:47Lex Fridman?

  First of all, welcome back, Sarah. Welcome back, Lee. You guys, I'm a huge fan of yours. You're incredible people. I should say thank you to Sarah for wearing really awesome boots. We'll probably overlay a picture later on, but why the hell didn't you dress up, Lee?

• 8:00Lee Cronin?

  This is me dressed up.

• 8:02Lex Fridman?

  You were saying that you're pink, that your thing is pink. My thing is black and white, the simplicity of it. Where's the pink? When did the pink, when did it hit you that pink is your color?

• 8:13Lee Cronin?

  I became pink about...

• 8:16Lee Cronin?

  I don't know, actually, maybe 2017? You know, did you know me when you first?

• 8:21Sara Walker?

  I think I met you pre-pink.

• 8:22Lee Cronin?

  Yeah, yeah, so about 2017, I think. I just decided I was boring and I needed to make a statement and red was too bright. So I went pink, salmon pink.

• 8:32Lex Fridman?

  Well, I think you were always pink. You just found yourself in 2017.

• 8:38Sara Walker?

  There's an amazing photo of him where there's like everybody in their black gown and he's just wearing the pink pants.

• 8:42Lee Cronin?

  Oh, that wasn't the wagon in university.

• 8:44Sara Walker?

  It's totally nuts.

• 8:45Lee Cronin?

  Hundred year anniversary. They got me to give the plenary and they didn't, they didn't find an outfit for me. So they were all wearing these silly hats and these gowns. And there was me dressed up in pink, looking like a complete idiot.

• 8:54Lex Fridman?

  We're definitely gonna have to find that picture and overlay it big, full screen, slow motion. All right, let's talk about aliens. We'll find places we disagree and places we agree.

• 9:07Lex Fridman?

  Life, intelligence, consciousness, universe, all of that. Let's start with a tweet from Neil deGrasse Tyson stating his skepticism about aliens wanting to visit Earth. Quote, "How egocentric of us to think that space aliens who have mastered interstellar travel across the galaxy would give..." Pardon the French, "would give a shit about humans on Earth. So let me ask you, would aliens care about visiting Earth, observing, communicating with humans?" Let's take a perspective of aliens, maybe Sarah, first. Are we interesting in the whole spectrum of life in the universe?

• 9:50Sara Walker?

  I'm completely biased, at least as far as I think right now, we're the most interesting thing in the universe. So I would expect, based on the intrinsic curiosity that we have and how much I think that's deeply related to the physics of what we are, that other intelligent aliens would want to seek out examples of the phenomena they are to understand themselves better. And I think that's kind of a natural thing to want to do. And I don't think there's any kind of judgment on it being a lesser being or not. It's like saying you have nothing to learn by talking to a baby. You have lots to learn, probably more than you two talking to somebody that's 90. So, um, yeah, so I think they absolutely would.

• 10:30Lex Fridman?

  So whatever the phenomena is that is human. There would be an inkling of the same kind of phenomenon with an alien species and they would be seeking that same.

• 10:39Sara Walker?

  I think there's got to be some features of us that are universal and I think the ones that are most interesting, and I hope I live in an interesting universe, are the ones that are driven by our curiosity and the fact that our intelligence allows us to do things that the universe wouldn't be able to do without things like us existing.

• 11:01Lex Fridman?

  We're going to define a lot of terms. One of them is interesting.

• 11:05Sara Walker?

  Yes.

• 11:05Lex Fridman?

  That's a very interesting term to try to define. Ali, what do you think? Are humans interesting for aliens?

• 11:12Lee Cronin?

  Well, let's take it from our perspective. We want to go find aliens as a species quite desperately. So if we put the shoe on the other foot, of course we're interesting. But I'm wondering, and assuming that we're at the right technological capabilities to go searching for aliens, then that's interesting. So what I mean is if there needs to be a massive leap in technology that we don't have, how will aliens prioritize coming to Earth and other places? But I do think that they would come and find us because they'd want to find out about our culture, what things are universal. What about, I mean, I'm a chemist, so I would say, well, is the chemistry universal, right? Are the creatures that we're going to find making all this commotion, are they made of the same stuff?

• 11:56Lee Cronin?

  What does their science look like? Are they off planet yet? I guess there's, so I think that Neil deGrasse Tyson is being slightly pessimistic and maybe trying to play the tune that the universe is vast and it's not worth them coming here. I don't think that, but I just worry that maybe we don't have the ability to talk to them. We don't have the universal translator. We don't have the right physics. But sure, they should come. We are interesting. I want to know if they exist. It would make it easier if they just came.

• 12:29Lex Fridman?

  So again, I'm going to use your tweets like it's Shakespeare and analyze it. So Sarah tweeted, thinking about aliens, thinking about aliens. So how much do you think aliens are thinking about other aliens, including humans? So you said, we humans want to visit, like we're longing to connect with aliens. Why is that? Can you introspect that? Is that an obvious thing that we should be? Like, what are we hoping to understand by meeting aliens? Exactly. Asking as an introvert, it's like, I ask myself this all the time. Why go out on a Friday night to meet people? What are you hoping to find?

• 13:10Lee Cronin?

  I think the curiosity, so when I saw Sarah put that tweet, I think I answered it actually as well, which was, we are thinking about trying to make contact. So they almost certainly are, certainly are. But maybe there's a number of classes. There are the, those aliens that have not yet made contact with other aliens like us. Those aliens have made contact with just one other alien and maybe it's an anticlimax in slime. Right? And aliens that have made contact with not just one set of intelligent species, but several. That must be amazing, actually. Literally, there is some place in the universe, there must be one alien civilization that's not made contact with not one, but two other intelligent civilizations.

• 13:49Lee Cronin?

  So they must be thinking about, there must be entire degree courses on aliens, thinking about aliens and cultural, universal cultural norms.

• 14:00Lex Fridman?

  Do you think they will survive the meeting? And by the way, Lee did respond saying, that's all the universe wants. So Sarah said, thinking about aliens, thinking about aliens. Lee said, that's all the universe wants. And then Sarah responded, cheeky universe we live in. So cheeky is a cheeky version of the word interesting, all of which we'll try to define mathematically.

• 14:24Sara Walker?

  Cheeky might be harder than interesting.

• 14:26Lex Fridman?

  Cause there's humor in that, too.

• 14:27Sara Walker?

  Yes.

• 14:28Lex Fridman?

  I think there's a mathematical definition of humor, but we'll talk about that in a bit.

• 14:32Lee Cronin?

  Yeah, sure there is, yeah.

• 14:33Lex Fridman?

  So if you're a graduate student, alien, looking at multiple alien civilizations, do you think they survive the encounters?

• 14:42Sara Walker?

  I think there's a tendency to anthropomorphize a lot of discussions about alien life, which is a really big challenge. So usually when I'm trying to think about these problems, I don't try to think about us as humans, but us as an example of phenomena that exists in the universe that we have yet to explain. And it doesn't seem to be the case that if I think about the features I would argue are most universal about that phenomena, that there's any reason to think that a first encounter with another lineage or example of life would be antagonistic. I think, yeah, and I think there's this kind of assumption.

• 15:24Sara Walker?

  I mean, going back to Neil deGrasse Tyson's quote, I mean, it kind of bothers me because there's a, I mean, I'm a physicist, so I know we have a lot of egos about how much we can describe the world, but that there's this like, because we understand fundamental physics so well, we understand alien life and we can kind of extrapolate. And I just think that we don't. And the quest there is really, you know, really to understand something totally new about the universe and that thing just happens to be us.

• 15:50Lee Cronin?

  I agree. I agree. There's something else more profound. I think Neil was just being, again, he's just trying to stir the pot. I would say from a, from a contingency point of view, I want to know how many ways does the universe build structures, build memories, right? That, and then I want to know if those memories can interact with each other. And if you have two different origins of life and then origins of intelligence and then these things become conscious, surely you want to go and talk to them and figure out what commonalities you share. And it might be that we're just unable to conceive of what they're going to look like. They're just going to be completely different, you know, infrastructure. But surely we'll want to go and find out a map. And surely curiosity

• 16:30Lee Cronin?

  is a property that evolution has made on Earth. And I can't see any reason that it won't happen elsewhere, because curiosity probably exists because we want to find innovations in the environment. We want to use that information to help our technology. And also curiosity is like planning for the future. Are they going to fight us? Are they, are we going to be able to trade with them? So I think that Neil's just, I don't know, maybe, you know, I mean, give a shit. That's really, I think that's really down on Earth, right? How would aliens categorize humans, do you think?

• 17:05Lee Cronin?

  How would we, so let's put it the other way around. Slime category. Maybe, no, no, no, we, maybe we could, the thing is a bit odd, right? Look at Instagram, Twitter, all these people taking selfies. I mean, does the universe is the ultimate state of consciousness? Thinking beings that take photographs themselves and upload them to an internet with other thinking beings looking at each other's photos. So I think that they will be.

• 17:28Sara Walker?

  What's wrong with that?

• 17:29Lee Cronin?

  I did not say there was anything wrong with it. It's consciousness manifested at scale. Yeah. Selfies on Instagram.

• 17:37Sara Walker?

  It's like the mirror test at scale.

• 17:38Lee Cronin?

  Yeah, I do think that curiosity is really the driving force of why we have our technology. Right? If we weren't curious, we wouldn't go out, left the cave. So I think that, so I think that Neil's got it completely wrong. In fact, actually, of course they'd want to come here. It doesn't mean they are coming here. We've seen evidence for that. I guess we can argue about that, right? But I think that we want, I desperately, and I know that Sarah does too, but I won't speak for you. You're here, you can, I desperately want to have missions to look for life in the solar system right now. I want to map life over the solar system. And then I want to understand how we can go and find life as quickly as possible at the nearest stars. And also at the same time, do it in the lab just to compensate, you know?

• 18:23Lee Cronin?

  So sure.

• 18:24Sara Walker?

  Yeah, I just one more point on this. If you think about sort of what's driven the most like features of our own evolution as a species, you could, and try to map that to alien species. I always think like optimism is what's going to get us furthest. And so I think a lot of people always think that it's like war and conflict is going to be the way that alien species will expand out into the cosmos. But if you just look at how we're doing it and how we talk about it, it's always our future in space is always, you know, built from narratives of optimism. And so it seems to me that if intelligence does get out in the universe, that it's going to be more optimism, curiosity driving it than war and conflict, because those things end up crushing you. So there might be some selective filter. Of course, this is me being an optimist.

• 19:08Sara Walker?

  I'm a half, half full kind of person, but.

• 19:10Lee Cronin?

  Is it obvious that curiosity?

• 19:13Lex Fridman?

  Not obvious, but what do you think? Is curiosity a more powerful force in the universe than violence and the will to power? So, uh, cause you said you frame curiosity as a way to also plan on how to avoid violence, which is an interesting framing of curiosity. But I could also argue that violence is a pretty productive way to operate in the world, which is like, that's one way to protect yourself. The best defense is offense.

• 19:44Lee Cronin?

  Um, I'm not qualified to answer this, but I'll have a go. I think vi- let's not talk about vi-

• 19:49Lex Fridman?

  That's the summary of this podcast.

• 19:52Lee Cronin?

  I would, yeah, but maybe I would, let's not call it violence, but I call it erasure. So if you think about, um, the way evolution works all the way, um, obviously call it assembly theory, but I won't. So if you say you, you, you build, curiosity allows you to open up avenues, new graphs, right? So new features you can play. What, what the ability to erase those things allows you to start again and do some pruning. So the universe, I think curiosity gets you furthest. Curiosity gets you rockets that land. It gets you robots that can make drugs. It gets you poetry and art and communication. And then, you know, I often think, wouldn't it be great in bureaucracy to have another world war? Not literally a world war now, please no world war, but a, the equivalent.

• 20:36Lee Cronin?

  So we get, remove all the admin bureaucracy, right? All the admin violence, get rid of it and start again. Do you know what I mean? Because you get layers and you get redundant systems built. So actually a reset, let's not call it violence, a reset in some aspects of our, um, culture and our, our technology allows us to then build more important things without the, cause how many, you know, how many cookies do I have to click on? How many thing, how many, how many extra clicks I do I have in the future of my life that I could remove and that a bit of a, a reset would, would allow us to, to, to, to start again. And maybe that's how I suppose our encounter with aliens will be. Maybe they will fight with us and say, ah, we're not as excited by you as we thought. We'll just get rid of you.

• 21:21Lex Fridman?

  Or they might wanna reset Earth.

• 21:23Lee Cronin?

  Yeah, why not?

• 21:23Lex Fridman?

  To be like, let's see how the evolution runs again. This seems like a, they've, uh, uh, there's nothing new happening here. They're observing for a while. This is just not, let's keep it more fun. Let's start with a fish again.

• 21:38Lex Fridman?

  I like how you equated violence to resetting your cookies. I suppose that's the kind of violence in this, this modern world where words are violence, resetting cookies.

• 21:49Lee Cronin?

  I don't know where that came from. I'm completely, yeah.

• 21:51Lex Fridman?

  That's poetic, really. Okay, so let's talk about life. What is life? What is non-life? What is the line between life and non-life? And maybe at any point, we can pull in ideas of assembly theory. Like, how do we start to try to define life? And for people listening, so Sarah identifies as a physicist and Lee identifies as a chemist. Of course, they are very interdisciplinary in nature in general, but.

• 22:23Lex Fridman?

  So what is life? Sarah?

• 22:28Lex Fridman?

  I love asking that question because it's so absurdly big.

• 22:30Sara Walker?

  I know. I love it. It's my absolute favorite question in the whole universe. So I think I have three ways of describing it right now. And I like to say all three of them because people latch on to different facets of them. And so the whole idea of what Lee and I are trying to work on is not to try to define life, but to try to find a more fundamental theory that explains what the phenomenon we call life. And then it should explain certain attributes. And you end up having a really different framing than the way people usually talk. So the way I talk about it, three different ways. Life is how information structures matter across space and time.

• 23:04Sara Walker?

  Life is, I don't know, this one's from you, actually. Simple machines constructing more complex machines. And the other one is the physics of existence, so to speak, which is life is the mechanism the universe has to explore the space of what's possible. That's my favorite.

• 23:22Lee Cronin?

  So can I, yeah, yeah, can I add on to that?

• 23:25Lex Fridman?

  Okay, can you say the physics one again? Physics of existence.

• 23:29Sara Walker?

  Yeah, the physics of existence. I don't know what to call it. You know, like, if you think of all the things that could exist, only certain things do exist. And I think life is basically the universe's mechanism of bringing things into physically existing in the, in the moment now.

• 23:44Lee Cronin?

  Yeah. Yeah, and what's what's another one? We were debating this the other day. So if you think about a universe that has nothing in it, that's kind of hard to conceive of, right? Because and this is where physicists really go wrong. They think of a universe with nothing in it. They can't. And you think. Nonexistence is really hard to think. Nonexist, yeah. And then you think of a universe with everything in it. That's really hard. And and you just you just have this white blob, right? This is everything. But the fact we have discrete stuff in the universe beyond, say, planets. So you've got stars, space, planet stuff, right? The boring stuff. But I would define life or say that life is where there are architectures, any architectures, and we should stop fixating on

• 24:28Lee Cronin?

  what is building the architectures to start with. And the fact that the universe has discrete things and it is completely mind blowing. If you think about it for one second, the fact there's any objects at all that and there's because for me, the the object is a proxy for a machine that built it. Some information being moved around, actuation, sensing, getting resource, and building these objects. So for me, everyone's been obsessing about the machine. But I'm like, forget the machine. Let's see the objects, the, you know, and I think in a way that assembly theory.

• 25:09Lee Cronin?

  We realized maybe a few months ago that assembly theory actually does account for the soul in the objects, not mystically like, say, Sheldon Exomorphic resonance or Leibniz's monodology, seeing souls in things. But when you see an object, and I've said this before, but this object is evidence of thought. And then there's a lineage of those objects. So I think what is fascinating is that you put it much more elegantly, but but the barrier between life and nonlife is accruing enough memories to then actuate. So so what that means is there are contingency, there are things that happen in the universe get trapped. These memories then have a causal effect on the future. And then when you get those concentrated in a machine and you're actually able in real time, able to integrate

• 25:55Lee Cronin?

  the past, the present with the future and do stuff, that's when you are most alive.

• 26:01Lex Fridman?

  You being the machine?

• 26:02Lee Cronin?

  Yes.

• 26:03Lex Fridman?

  Wait a minute, but why is the object? So one of the ways to define life that Sarah said is simple machines creating complex machines. So there's a million questions there. So how the hell does a simple machine create a complex machine?

• 26:20Lee Cronin?

  By mutation. So this is what we were talking about at the beginning. You have the minimum replicator, so molecule. So this is what I was trying to convince Sarah of the mechanism get there years ago, I think. But then you've been building on it and saying you have a small, you have a molecule that can copy itself, but then that there has to be some variability. Otherwise, it's not going to get more functional. So you need to add bits on. So you have a minimum molecule that can copy itself, but then it can add bits on and that can be copied as well. And those add-ons can give you additional function to be able to acquire more stuff to exist. So existence is weird, but the fact that there is existence is why there is life. And that's why I realized a few days ago that there must be, that's why alien life

• 27:04Lee Cronin?

  must be everywhere, because there is existence.

• 27:07Lex Fridman?

  Is there like a conservation of cheeky stuff happening? So like, how can you keep injecting more complex things? Like, doesn't the machine that creates the object need to be as or more powerful than the things it creates? So how can you get complexity from simplicity?

• 27:30Lee Cronin?

  So the way you get complexity from simplicity is that you, I would, this, I'm just making this up, but this is kind of my notion, that you have a large volume of stuff. So you're able to get seeds, if you like, random cues from the environment. So you just use those objects to basically write on your tape, ones and zeros, whatever. And that is, that is necessarily rich, complex. Okay. But it has a low assembliness, but even though it has a high assembly number, we can talk about that. But then when you start to then integrate that all into smaller volume as over time. And you become more autonomous, you then make the transition. I don't know what you think about that.

• 28:13Sara Walker?

  I think the easiest way to think about it is actually, which I know is a concept you hate, but I also hate, which is entropy, but people are more familiar with entropy than what we talk about in assembly theory. And also the idea that, like, say physics as we know it involves objects that don't exist across time, or as we would say, low memory objects. So one of the key distinctions that-

• 28:37Lex Fridman?

  Low memory objects.

• 28:38Sara Walker?

  Yeah, so physics is all-

• 28:40Lee Cronin?

  Physicists are low memory-

• 28:41Sara Walker?

  Low memory objects.

• 28:43Lex Fridman?

  Physicists are creators of low memory objects, or manipulators of low memory objects.

• 28:49Lee Cronin?

  Absolutely.

• 28:49Lex Fridman?

  It's a very nice way of putting it. Okay, sorry, go. Sorry to interrupt.

• 28:54Sara Walker?

  No, no, it's fine. I like it too. It's very funny. But I think it's a good way of phrasing it, because I think, you know, this kind of idea we have in assembly theory is that, you know, physics as we know it has basically removed time as being a physical observable of an object. And the argument I would make is that when you look at things like water bottles or us, we're actually things that exist that have a large extent in time. So we actually have a physical size in time, and we measure that with something called the assembly index in molecules, but presumably everyone should have sort of a...

• 29:32Sara Walker?

  Do you want to explain what assembly?

• 29:33Lex Fridman?

  Yeah, let's, you know what? Let's step back and start at the beginning. What is assembly theory? Lee sent me some slides. There's a big sexy paper coming out, probably, maybe, I don't know.

• 29:46Lee Cronin?

  We've almost finished it.

• 29:49Sara Walker?

  Almost, almost finished it.

• 29:50Lex Fridman?

  That's also a summary of science. We're almost done.

• 29:53Sara Walker?

  Yes.

• 29:54Lee Cronin?

  Well, no, no, we're almost done.

• 29:55Lex Fridman?

  The history of science.

• 29:56Lee Cronin?

  We are ready to start an interesting discussion with our peers.

• 30:00Lex Fridman?

  Right. You're the machine that created the object, and we'll see what the object takes us. All right, so what is assembly theory?

• 30:07Sara Walker?

  Yeah, well, I think the easiest way for people to understand it is to think about- Assembly and molecules, although the theory is very general, doesn't just apply to molecules. And this was really Lee's insight, so it's kind of funny that I'm explaining it, but um.

• 30:21Lee Cronin?

  I'll mark you.

• 30:22Sara Walker?

  Okay, all right, I'm ready, I'm ready. You can tell me where I get the checkmarks minus, but.

• 30:26Lee Cronin?

  It's your theory as well.

• 30:27Sara Walker?

  Yeah, I know. But imagine a molecule, um, and then, and then you can, you know, break the molecule apart into elementary building blocks. They happen to be bonds. And then you could think of all the ways, from molecular assembly theory, you could think of all the ways of building up the original molecule. So there's all these paths that you can assemble it. And the sort of rules or assembly is you can use pieces that have been generated already. So it has this kind of recursive property to it. And so that's where kind of memory comes into assembly theory. And then the assembly index is the shortest path in that space. So it's supposed to be the minimal amount of history that the universe has to undergo in order to assemble that particular object. And the reason that this is significant is we figured out how to measure that with a mass spec in the lab.

• 31:12Sara Walker?

  And we had this conjecture that if that minimal number of steps was sufficiently large, it would indicate that you required a machine or a system that had information about how to assemble that specific object, because the combinatorial space of possibilities is getting exponentially large as the assembly index is increasing.

• 31:27Lex Fridman?

  So just sorry to interrupt, but so that means there's a sufficiently high assembly index that if observed in an object is an indicator that something lifelike created it? Or is the object itself lifelike?

• 31:45Sara Walker?

  Um, both. But you might want to make the distinction that a water bottle is not life, but it would still be a signature that you were in that domain of physics and I might be alive. So um.

• 31:58Lex Fridman?

  So there will be potentially a lot of arguments about where the line, at which assembly index does interesting stuff start to happen?

• 32:07Sara Walker?

  The point is, we can make all the arguments, but it should be experimentally observable and, and Lee can talk more about that part of it. But the, the point I want to make about it is there was always this intuition that I had that there should be some complexity threshold in the universe above which you would start to say, whatever physics governs life actually becomes operative. And I think about it a little bit, like we have Planck's constant, which, you know, like, and we have the fine structure constant. And then this sort of assembly threshold is basically another sort of. A potentially constant of nature, it might depend on specific features of the system, but which we debate about sometimes. But but then, when you're past that, you have you have to have some other explanation than the current explanations we have in physics, because now you're in high memory.

• 32:51Lee Cronin?

  Yeah.

• 32:52Sara Walker?

  The things actually require time for them to exist, and time becomes a physical variable.

• 32:59Lex Fridman?

  The path to the creation of the object is the memory.

• 33:02Lee Cronin?

  Yeah.

• 33:03Lex Fridman?

  So you need to consider that.

• 33:04Sara Walker?

  Yeah, but the but the point is, that's a feature of the object. So it's it's it so when I think of all the things in this room, you know, we see the the projection of them as a water bottle, but assembly theory would say that this is a causal graph of all the ways the universe can create this thing. That's what it is as an object. And we're all interacting, a causal graph, and and most of the creativity in the biosphere is because a lot of the objects that exist now are huge in their structure across time, four billion years of evolution to get to us.

• 33:33Lex Fridman?

  So is it possible to look at me and infer the history that led to me?

• 33:39Sara Walker?

  If you.

• 33:40Lex Fridman?

  Me as a human.

• 33:41Sara Walker?

  You as an individual might be hard. You as a representative of a population of objects that have high assembly with similar causal history and structure that you can communicate with, i.e. other humans, you can infer a lot, probably.

• 33:54Lee Cronin?

  Yeah, also with them.

• 33:55Sara Walker?

  Which we do, genomically even. I mean, it's not like like we have a lot of information and us, we can reconstruct histories from. Assembly is saying something slightly deeper.

• 34:03Lee Cronin?

  Yeah, one thing to add, I mean, it's not just about the object, but the objects occur, and not just objects with high assembly number, because you can have random things that have a high assembly number, but they must have, there must be a number of identical copies. So you know you're getting getting away from the random, because you could take a snapshot. This is why, it's not like I hate entropy, I love entropy, when used correctly, but it's about the problem of entropy, you have to have a labeler. And so so you can label the beginning and the end, the start and the finish, you know, what you can do in assembly is say, oh, I have a number of objects in abundance, they all have these features, and then you can infer. And one of the things that we debated a lot, particularly during lockdown, because I almost went insane trying to crush the produce the assembly equation. So we came up with the assembly equation.

• 34:47Lee Cronin?

  I had, just imagine this, so you have this string where Oh, actually, it makes me, makes me sick trying to remember it. It was so, it did my head in for a long time.

• 34:57Sara Walker?

  Dramatic.

• 34:58Lee Cronin?

  Yeah, because I couldn't, so if you just have a string of, say, words, say, you know, a series of words, a series of letters. So you just have AAA, BBB, CCC, DDD, and you, and you find that object and you just have four As, four Bs, four Cs, four Ds together. Boom. Then, and that, that you measured that, so you physically measured that string of letters. Then what you could do is you can infer sub graphs of maybe the four As, the four Bs, the four Cs and the four Cs. We don't see them in the real world, you just infer them. And I really got stuck with that because there's a problem to try and work out what's the difference between a long, you know, a physical object and this assembly space of objects that we realized the best way to put that is infer in time.

• 35:44Lee Cronin?

  That, so although we can't infer your entire history, we know at some point the four As were made, the four Bs were made, the four Cs were made, the four Ds were made, and they all got added together. And, and that's one really interesting thing that's come out of the theory. But the killer, when we knew we were going beyond, um, and, um, beyond standard complexity theories, which was incredibly successful, is that we realized we could start to measure these things for real across domains. So the assembly index is actually the intrinsic property of all stuff that you can break into components. Particularly molecules are good because you can break them up into smaller molecules, into atoms.

• 36:26Lee Cronin?

  The challenge will be making that more general across all the domains, but we're working on it right now and I think the theory will do that.

• 36:31Lex Fridman?

  So components, domains, so you're talking about basically measuring the complexity of an object in what biology, chemistry, physics, that's what you mean by domains.

• 36:44Lee Cronin?

  Complexity of testers.

• 36:45Lex Fridman?

  Sociology.

• 36:46Lee Cronin?

  Computers, complexity of memes, you know.

• 36:49Lex Fridman?

  Memes?

• 36:49Lee Cronin?

  Yep.

• 36:50Lex Fridman?

  What, what is that, ideas?

• 36:52Lee Cronin?

  Yeah, I mean, so one of the.

• 36:54Sara Walker?

  Ideas are objects in assembly theory though.

• 36:55Lee Cronin?

  Yeah.

• 36:56Lex Fridman?

  They are.

• 36:57Sara Walker?

  They're physical things. They're just features of the causal graph. I mean, the fact I can talk to you right now is because we're exchanging structure of our assembly space.

• 37:05Lex Fridman?

  So, conversation is the exchanging structures in assembly space. What is assembly space?

• 37:13Sara Walker?

  When I started working on Origins of Life, I was writing about something called top-down causation, which a lot of philosophers are interested in and people that worry about the mind-body problem. But the whole idea is, you know, if we have, you know, the microscopic world of physics is causally complete, it seems like there's no room for higher-level causes, like our thoughts to actually have any impact on the world. And that seems problematic when you get to studying life and mind, because it does seem that "emergent properties" do matter to matter. And so, and then there's this other sort of paradoxical situation where information looks like it's disembodied. So, we talk about information, like it can just move

• 37:54Sara Walker?

  from any physical system to any other physical system, and it doesn't require, like, you don't have to specify anything about the substrate to talk about information. And then there's also, the way we talk about mathematics is also disembodied, right? Like, the platonic world of forms. And I think all of those things are hinging that we really don't know how to think about abstractions as physical things. And really, I think what assembly theory is pointing to is what we're missing there is the dimension of time. And if you actually look at an object being extended across time, what we call information and the things that look abstract are things that are entangled in the histories of those objects. They're features of the overlapping assembly space.

• 38:39Sara Walker?

  So, they look abstract because they're not, you know, part of the current structure, but they're part of the structure, if you thought about it, as like the philosophical concept of a hyper-object, an object that's too big in time for us to actually to resolve. And so, I think information's physical. It's just physical in time, not in space.

• 38:58Lex Fridman?

  Too hyper object, too difficult for us to resolve. So we're supposed to think about of life as this thing that stretches through time. And there's a causation chain that led to that thing. And then you're trying to measure something with the assembly index about.

• 39:15Sara Walker?

  The assembly index is the ordering, the or like, you could think of it as like a partial ordering of all the things that can happen. So in in thermodynamics, we coarse grain things by temperature and pressure. In assembly theory, we coarse grain by the number of copies of an object and the assembly index, which is basically, if you think of the space of all possible things, it's like a depth of how far you've gone into that space and how much time was required to get there.

• 39:39Lex Fridman?

  In the shortest possible version. Not at not average, because can't you just 3D?

• 39:46Sara Walker?

  You're going to kill me with that question.

• 39:48Lex Fridman?

  Not, not, not 3D. Can't you always 3D print the thing?

• 39:52Sara Walker?

  That's like stabbing in the heart.

• 39:53Lee Cronin?

  No, because I had such fights. So Sarah's team and my team are writing this paper at the moment.

• 39:58Sara Walker?

  And. It's so funny.

• 40:00Lee Cronin?

  I think we kind of share the, at the beginning, you were like, no, that's not right. Oh, yes, right. And we're doing this for a bit. And then the problem is when you build a theory and build the intuition, there's some certain features, right, of the theory that almost felt like I was being religious about, say, right, you have to do this. A good assembler, assembly theorist does this, does this, does this. And Sarah's postdoc, Daniel, and my postdoc, Abhishek, and they were both.

• 40:23Sara Walker?

  We're both brilliant.

• 40:24Lee Cronin?

  They're brilliant, but they were like, no, we don't, we don't buy that. And I was like, it is, is, they were like, well, Lee, actually, I thought you're the first to say that, you know, you can't, if you can't explain it, it doesn't, and you can't do an experiment that doesn't exist. And that saved me. And I said to Abhishek, Abhishek's my postdoc in Glasgow, Daniel was Sarah's postdoc in ASU. I was like, I have the experimental data. So when I basically take the molecules and chop them up in the mass spec, the assembly number is never the average, it's always the shortest. It's an intrinsic property. And then the penny dropped for Abhishek. So, okay. So I had these things that we had to believe to start with or to trust. And then we've done the math and it comes out. And they now have the shortest path. Actually, it's up, that explains why the shortest path, here's why the shortest path's

• 41:09Lee Cronin?

  important, not the average. Shortest path needs you to identify when the universe has basically got a memory, not an average. So what you want to be able to do is to say, what is the minimum number of features that I want to be able to see in the universe? When I find those features, I know the universe has had a coherent memory and is basically alive. And, and so that gives you the lower bound. So that's like, of course, there's going to be other paths. We can be more ridiculous, right? We can have other paths, but it's just the minimum. So probabilistically, at the beginning, because assembly theory was built as a measure for biosignatures, I needed to go there. And then I realized it was intrinsic.

• 41:52Lee Cronin?

  And then Sarah realized it was intrinsic and these hyperobjects were coming and we were kind of fusing that notions together. And then the team were like, yeah, but if I have enough energy and I have enough resources, I might not take the shortest path. I might go a bit longer. I might take a really long path because it allows me then to, to do something else. So what you can do is, let's say I've got two different objects, A and B, and they both have different shortest paths to get them. But then, if you want to make A and B together, they will have a compromise. So in the joint assembly space, they might, that might be an average, but actually it's the shortest way you can make both A and B with a minimum amount of resource in time. So suddenly you then layer these

• 42:34Lee Cronin?

  things up. And so the average becomes not important, but it's a, as you literally overlap those sets, you get a new shortest path. And so what we realized time and time again, when we're doing the math, the shortest path is intrinsic, is fundamental, and is measurable, which is kind of mind blowing.

• 42:53Lex Fridman?

  So what we're talking about, some basic ingredients, maybe we'll talk about that, what those basic ingredients could be and how many, when you say shortest path, how many steps it takes to turn those basic ingredients into the final.

• 43:09Lex Fridman?

  Meal. So how to make a pizza, what's the shortest way to make a pizza?

• 43:14Sara Walker?

  Or a pie, an apple pie.

• 43:16Lex Fridman?

  An apple pie, that's right.

• 43:17Lee Cronin?

  And a pizza and a pie together.

• 43:19Lex Fridman?

  Scratch.

• 43:20Lee Cronin?

  Yeah.

• 43:20Lex Fridman?

  So there's a lot of ways. There's the shortest way and then, you know, you take the full spectrum of ways and there's probably an average, like, duration for a noob to make an apple pie. Is the average interesting still? If you measure the average length of the path to assemble a thing, does that tell you something about the way nature usually does it? Versus

• 43:51Lex Fridman?

  something fundamental about the object, which I think is what you're aiming at with the assembly index?

• 43:55Lee Cronin?

  Yeah, I mean, look, we all love to quantify things. The minimum path gives you the lower bounds. You know, you're detecting something, you know, you're inferring something. The average tells you about really how the objects are existing in the ecosystem or the technology. And, and that, and there has to be more paths explored because then you can

• 44:16Lee Cronin?

  happen upon other memories and then condense them down. I'm not making too much sense, but if you look at, say, let's just say, I mean, maybe we're going to get to alien civilizations later, right? But I, I would argue very strongly that Alien Civilization A and Alien Civilization B,

• 44:33Lee Cronin?

  they're different assembly spaces. So they're kind of going to be a bit messed up if they happen to come on another. Only when they find some joint overlap in their technology. Because if aliens come to us and we, they don't share any of the causal graph we've shown, but hopefully they share the periodic table and some other, and bonds and things. So we're going to have to really think about the language to talk to us aliens by inferring, by using assembly theory to infer

• 44:59Lee Cronin?

  the, their language, their technology and other bits and bobs. And the shortest path will help you do that quickly.

• 45:05Lex Fridman?

  All right, so all, all aliens in the causality graphs have a common ancestor in the?

• 45:11Sara Walker?

  If the building blocks are the same, which means they live in the same universe as us.

• 45:14Lex Fridman?

  So is this?

• 45:15Sara Walker?

  It depends on how far back in time you go, though.

• 45:17Lex Fridman?

  But the universe has all the same building blocks?

• 45:21Sara Walker?

  Yeah.

• 45:21Lex Fridman?

  And like, we have to assume that. So there's not different classes of causality graphs, right? No. The universe doesn't just say like, here, you get the red causality graph and you get the blue one. There's basic ingredients and they're geographically constrained or constrained in space or time or something like that.

• 45:45Sara Walker?

  They're constrained in time because only by the virtue of the fact that you need enough time to have passed for some things to exist. So the universe has to be big enough in time for some things. So just one point on the shortest path versus the average path, which I think we'll get to this is you had a nice way of saying it's like the minimal compression is the shortest path for the universe to produce that. But it's also like the first time in the ordering of events that you might expect to see that object. But the average path tells you something about the actual steps that were realized and that becomes an emergent property of that object's interaction with other objects. So it's not an intrinsic feature of that object. It's a feature of the interactions with other things. And so one of the nice features of assembly is you've basically gotten rid of, you just

• 46:30Sara Walker?

  look at the things that exist and you've gotten rid of the mechanisms for constructing them in some sense, like the machines are not as important in the current construction of the theory, although I would like to bridge it to some ideas about constructors. But then you can only communicate with things as Lee was saying, if you have some overlap in the past history. So if you had an alien species that had absolutely no overlap, then there would be no means of communication. But as we become, you know, as we progress further and further in time and more things become possible because the assembly spaces are larger, because you can have a larger assembly space in terms of index and also just the size of the space because it's exponentially

• 47:13Sara Walker?

  growing, then more things can happen in the future. And the example I like to give is actually when we made first contact with gravitational waves because, you know, that's an alien phenomenon that's been permeating our planet, not alien in life, but alien, like something we had never knew existed. It's been, you know, like we're, you know, there's gravitational waves rippling through this room right now. But we had to advance to the level of Einstein writing down his theory of relativity and then 100 years of technological development to even quote unquote, see that phenomena.

• 47:47Lex Fridman?

  So the, okay, to see that phenomena, our causal graph have to start intersecting.

• 47:54Sara Walker?

  Yeah, we needed the idea to emerge first, the abstraction, right? And then we had to build the technology that could actually observe features of that abstraction.

• 48:02Lex Fridman?

  So the, the nice promising thing is over time, the graph can grow, so it can start overlapping eventually.

• 48:08Sara Walker?

  Yeah, so the interesting feature of that graph is there was an event, you know, 1.4 billion years away of a black hole merger that we detected on our detector. And, you know, now suddenly we're connected through this communication channel with this distant event in our universe that, you know, if you think about 1.4 billion years ago, what was happening on this planet, or even further back in time, that, you know, there is common physics underlying all those events, but even for those two events to communicate with.

• 48:35Lee Cronin?

  Now I understand what you were going on about the other week.

• 48:37Sara Walker?

  Yeah, I'm sorry, this is a really abstract example, but, but it's sort of.

• 48:42Lex Fridman?

  Your causal graphs are now overlapping.

• 48:44Sara Walker?

  Yeah, so, well, let's just say now our causal graphs are overlapping in the deep past.

• 48:49Lee Cronin?

  Oh, I like it, so you made it.

• 48:50Sara Walker?

  I totally missed it.

• 48:51Lex Fridman?

  Oh, the 1.6 billion.

• 48:52Sara Walker?

  Yeah.

• 48:52Lee Cronin?

  You made a connection with it. No, I do like that.

• 48:54Sara Walker?

  No, no, you can tell me what your epiphany is now, that's good.

• 48:57Lee Cronin?

  Because I was.

• 48:58Sara Walker?

  And I should get the jokes before 30 seconds after, so.

• 49:01Lex Fridman?

  Oh, I get it now.

• 49:04Sara Walker?

  No, it's all right, I'm slow.

• 49:05Lex Fridman?

  The joke from two minutes ago.

• 49:06Sara Walker?

  I'm slow on the uptake here.

• 49:07Lee Cronin?

  I wasn't able to comprehend what you were talking about when saying the channel communicating to the past, but what you're saying is we were able to infer what happened 1.4 billion years ago. We detected the gravity wave. I mean, I think it's amazing that, you know, at that time, we weren't even, we were just becoming multicellular, right? It's like insane. And then we, we, we progressed from multicellular-arity through to technol-technology and built the detector and then for, you know, and then we just extrapolate backwards. So, so I, although we haven't, didn't do anything back to the graph back in time, we understood this existence then overlapped going forward and that.

• 49:43Sara Walker?

  Well, that's because our graphs are larger.

• 49:45Lee Cronin?

  Yeah, but that means that has a, that has a consequence. One of the things I was trying to say is like I'm. I'm, I'm, I think, I don't know, Sarah might be, she can correct me, information first, and I'm a object-first kind of guy. So I mean, as things that get constructed, there has to be this transition in random constructions. So when the constructing, the object that's being constructed by the process bakes in that memory, and those memories then add on and add on and add on. So as it becomes more competent, and life is about taking those memories and compressing them, increasing their autonomy. And, and so I think that, you know, like, the cell that we have in biology on earth is our way of doing that,

• 50:27Lee Cronin?

  that really the maximum ability to take memories and to act on the future.

• 50:31Sara Walker?

  Oh, I think that's mathematics.

• 50:33Lee Cronin?

  Um, no. Mathematics doesn't exist.

• 50:36Sara Walker?

  No, but that's the point. The point is that abstractions do exist. They're real physical things. We call them

• 50:43Lee Cronin?

  Okay.

• 50:43Sara Walker?

  abstractions. But the, the point about mathematics that I think is, so I, I don't, I don't disagree. I think you're object-first and I'm information-first, but I think I'm, I'm only information-first in the sense that I think the thing that we need to explain is why, what abstractions are and what they are as physical things. Because of all, all of human history, we've thought that there were these properties that are disembodied, exist outside of the universe. And really, they do exist in the universe, and we just don't understand what their physics is. So I think mathematics is a really good example. We do theoretical physics with math, but imagine doing physics of math, and then thinking about math as a physical object. And math is super interesting. I think this is why

• 51:25Sara Walker?

  we think it describes reality so well, because it's the most copyable kind of information. It retains its properties when you move it between physical media, which means that it's very deep. And, and so it seems to describe the universe really well, but it probably is because it's information that's very deep in our past. And it's just, we invented a way of communicating it very effectively between us.

• 51:46Lee Cronin?

  Isn't math more fundamental, isn't the assembly of the graph, isn't basically, I'm gonna sound, I sound completely boring. It's like math, assembly theory invented math, but it did. It has to be.

• 51:59Sara Walker?

  Okay.

• 52:02Lex Fridman?

  So what is, uh, what is math exactly? It's a, uh, a nice simplification, a simple description of what?

• 52:17Lee Cronin?

  So we have a computer scientist, a physicist and a chemist here.

• 52:20Lex Fridman?

  Walk into a bar.

• 52:21Lee Cronin?

  I think the chemist is going to define math and you guys can correct me.

• 52:24Sara Walker?

  Go for it.

• 52:25Lee Cronin?

  I would say.

• 52:26Sara Walker?

  Let, let, let it honestly. We're ready.

• 52:29Lee Cronin?

  I think the ability to, um, to label objects and, uh, and place them into classes and then do operations on the objects is what math is.

• 52:39Lex Fridman?

  So on that point, what does it mean to be object first versus information first? So what, what's the difference between object and information when you get to that low fundamental level?

• 52:50Lee Cronin?

  Well, I might change my view. So I'm stuff first, the stuff. And then when stuff becomes objects, it has to invent information. And then the information acts on more stuff and becomes more objects. So I think there is a transition to information that occurs when you go from stuff to objects.

• 53:08Sara Walker?

  Meantime though.

• 53:09Lee Cronin?

  Yeah.

• 53:09Lex Fridman?

  Information is emergent.

• 53:12Lee Cronin?

  Not emergent. Information is actionable memories from the universe. So when, when memories become actionable, that's information.

• 53:23Lex Fridman?

  But there's always memory, but it's not actionable.

• 53:27Lee Cronin?

  Yeah. And then it's not information.

• 53:28Lex Fridman?

  And actionable is what you can create.

• 53:31Lee Cronin?

  You can use it. If you can't use it, then it's not information. If you can't transmit it, if you, if it doesn't have any causal consequence.

• 53:38Lex Fridman?

  Falls in the forest. I don't understand why is that not information?

• 53:42Lee Cronin?

  It's not information. It's, it's, um, it's, uh.

• 53:45Lex Fridman?

  Stuff.

• 53:46Lee Cronin?

  It's stuff happening, but it's not, it's not causal. Yeah, it, yeah, we can, this is cool.

• 53:51Lex Fridman?

  It's happening.

• 53:51Lee Cronin?

  No, I know.

• 53:52Lex Fridman?

  The happening requires information.

• 53:54Lee Cronin?

  No, no, no, no, no.

• 53:55Lex Fridman?

  Stuff is always happening.

• 53:57Lee Cronin?

  No, this is where the physicists get and the mathematicians get themselves in a loop because they think the universe, I mean. I think, say, Max Tegmark is very playful and say like the universe, universe is just math. Well, the universe is just math, then we may as well not bother having any conversation because the conversation already written. We just may as well go to the future and say, can you just give us the conversation? It's happened already. So I think the problem is that mathematicians are so successful at labeling stuff and so successful understanding of stuff through those labels, they forget that actually those labels had to emerge and that information had to be built on those memories. So memory in the universe, so constraints, graph, when they become actionable and the graph can loop back on itself or interact with other graphs and they can intersect,

• 54:41Lee Cronin?

  those memories become actionable and therefore their information. And I think you just changed my mind on something pretty big, but I don't have a pen, so I can't write, I'm gonna write it down later, but roughly the idea is, is like you've got these, these two graphs of objects of stuff that you have memories. And then when they intersect and then they can act on each other, that's maybe the mechanism by which information is then, so then you can then abstract. So when one graph can then build another graph and say, hey, you don't have to go through all the nonsense we had to go through, here's literally the way to do it. Stuff always comes first, but then when stuff builds the abstraction, the abstraction can be then teleported onto other stuff.

• 55:20Lex Fridman?

  And the abstraction is the looping back power. Okay.

• 55:24Lee Cronin?

  Am I making, I don't know, I got stuck.

• 55:26Lex Fridman?

  Yeah, so first, God made stuff. Then after that, when you start to be able to form abstractions, that's when.

• 55:35Lee Cronin?

  God is the memory the universe can remember.

• 55:39Lex Fridman?

  God is the memory the universe can remember. Otherwise, there's no way.

• 55:43Sara Walker?

  Humans are gonna be deciphering that statement hundreds of years from now. What the hell does that mean?

• 55:46Lex Fridman?

  What do the humans mean by this?

• 55:48Lee Cronin?

  Hey, look, don't diss my, my one liners.

• 55:51Sara Walker?

  No, I wasn't dissing it. It just sounded very cheesy.

• 55:54Lee Cronin?

  It took me 15 seconds to come up with that.

• 55:55Sara Walker?

  I don't know what it means. What does it mean?

• 55:58Lex Fridman?

  Okay, wait, we need to, how do we get on to this? We were time causality mathematics. So what is mathematics in this picture of stuff?

• 56:14Lee Cronin?

  Objects, memory, and information. What exactly is mathematics? It's the most efficient labeling scheme that you can apply to lots of different graphs. Well, the labeling scheme doesn't make it sound useful.

• 56:31Sara Walker?

  Can I try?

• 56:32Lee Cronin?

  Yep, sure, please. Have you rejected my definition of mathematics? I'm shocked.

• 56:36Sara Walker?

  Yeah, no, I'm sorry.

• 56:38Lee Cronin?

  But it's correct. Go, I'm sorry.

• 56:41Sara Walker?

  Excellent. No, I mean, I think, I think we have a problem, right? Because we can't not be us, like, we're stuck in the shells we are and we're trying to observe the world. And so mathematics looks like it has certain properties. And I guess the thought experiment I find is useful is to try to imagine if you were outside of us, looking at us as physical systems using mathematics, what would be the specific features you associate to the property of understanding mathematics and being able to implement it in the universe? Right? And when you do that, mathematics seems to have some really interesting properties relative to other kinds of abstraction we might talk about, like language or artistic expression. One of those properties is the one I mentioned already, that is really easy to copy between

• 57:26Sara Walker?

  physical media. So if I give you a mathematical statement, you almost immediately know what I mean. If I tell you the sky is blue, you might say, is it cobalt blue? Is it azure blue? What color blue do you mean? And you have a harder time visualizing what I actually mean. So mathematics carries a lot of meaning with it when it's copied between physical systems. It's also the reason we use it to communicate with computers. And then the second one is it retains its property of actually what it can do in the universe when it's copied. So the example I like to give there is think about like Newton's law of gravitation. It's actually, it's a compressed regularity of a bunch of phenomena that we observe in the universe. But then that information actually is causal in a sense that it allows us to do things

• 58:08Sara Walker?

  we wouldn't be able to do without that particular knowledge and that particular abstraction. And in this case, like, launch satellites to space, or send people to Mars, or whatever it is. So if you look at us from the outside and you say, what is it for physical systems to invent a thing called mathematics and then to use? And then it to become a physical observable. Mathematics is kind of like the universally copyable information that allows new possibility spaces to be open in the future because it allows this kind of ability to map one physical system to another and actually understand the general principles.

• 58:44Lex Fridman?

  So is it helping the overlap of causal graphs then?

• 58:49Lee Cronin?

  Yes.

• 58:49Lex Fridman?

  By mapping?

• 58:50Sara Walker?

  Oh, I think that's the explanation for what it is in terms of the physical theory of assembly would be some feature of the structure of the assembly spaces of causal graphs and their relationship to each other. So for example, and I mean, this is things that we're going to have to work out over the next few years. I mean, we're in totally uncharted conceptual territory here. But as is usual, diving off the deep end. But I would expect that we would be able to come up with a theory of like, why is it that some physical systems can communicate with each other? Like language, language is basically because we're objects extended over time and some of the history of that assembly space actually overlaps. And when we communicate, it's because we actually have shared structure in our causal history.

• 59:34Lee Cronin?

  Let me have another quick go at this, right? So I think we all agree. So I think we take mathematics for granted because we've gone through this chain, right? You know, we all, we all share a language now. Okay. And we can, well, we share lang, so we have languages that we can, we can make interoperable. And, and so whether you're speaking, I don't know, all the different dialects of Chinese, all the different dialects of English, French, German, whatever, you can interconvert them. The interesting thing about mathematics now is that everybody on planet Earth, every human being and computers share that common language. That language was constructed by a process in time. So what I'm trying to say is that assembly invented math is those, those right from

• 1:00:16Lee Cronin?

  the, you know, mathematics didn't occur, it didn't exist before life. Abstraction was invented by life, right? That doesn't mean that the universe wasn't capable of mathematical things.

• 1:00:26Lex Fridman?

  Wait, wait a minute. Can we just ask that, that old famous question, is math invented or discovered? So when you say assembly invented. Or whatever.

• 1:00:36Sara Walker?

  Well, someone might interpret this simply as a mathematical theory, but sorry.

• 1:00:40Lex Fridman?

  Right.

• 1:00:40Lee Cronin?

  Are we arguing?

• 1:00:41Lex Fridman?

  Exactly.

• 1:00:42Lee Cronin?

  Are we arguing now?

• 1:00:42Lex Fridman?

  That's what it sounds like. Are we discovering?

• 1:00:45Lee Cronin?

  No. Well, yes and no. I would say.

• 1:00:48Lex Fridman?

  And you call mathematics a language.

• 1:00:50Lee Cronin?

  Mm hmm. I would say that. Look, I'm pretty sure that there are some very common seeds of mathematics in the universe. Right. But actually, not the mathematics that we are finding now is not discovered. It's invented. And but even though I think those two terms are very triggering, and I don't think they're necessarily useful, because I think that what people do, the mathematicians that say, oh, mathematics was discovered, because they live in a universe where there is no time and it just all exists. But what I'm saying is, and I think in the same way you can create, let's say, I'm going to go and create and make a piece of art.

• 1:01:30Lee Cronin?

  Did I make that piece of art? Or did I discover it? Like inventing the airplane. Did I invent the airplane? Let's stick with the airplane. The airplane is a good one. Let's say, did I discover the airplane? Well, in a way, the universe discovered the airplane because it just chucked a load of atoms together and a load of random human beings want to do stuff. And then we discovered the airplane in the space of possibilities. But here's the thing, when the space of possibilities is so vast, infinite almost, and you're able to actualize one of those in an object, then you are inventing it. So in mathematics, because there are infinite number of theorems, the fact you're actually pulling, there's no difference between inventing a mathematical structure and inventing the airplane. They're the same thing.

• 1:02:14Lee Cronin?

  But that doesn't mean that now the airplane exists in the universe. It's something weird about the universe that, you know. So I think that the more, this is the thing that you probably, the more memory required for the object, the more invented it is. So when a mathematical theorem has a, has a, needs more bytes to store it, the more invented it is, and the less bytes, the more discovered it is.

• 1:02:39Lex Fridman?

  But everything then is invented. It's just more or less invented.

• 1:02:42Lee Cronin?

  Absolutely.

• 1:02:43Lex Fridman?

  Okay.

• 1:02:44Sara Walker?

  The universe has to generate everything as it goes.

• 1:02:46Lee Cronin?

  Yeah.

• 1:02:48Lex Fridman?

  And it wasn't there in the beginning. And the way we're thinking it, when you're thinking about the difference between an event and a discovered is because we're throwing away all the memory. Yeah. So if you start to think in terms of causality and time, then those things become the same. Everything is invented.

• 1:03:04Sara Walker?

  And the idea is to make everything intrinsic to the universe. So I think one of the features of assembly theory is we don't want to have external observers. There's been this long tradition in physics of trying to describe the universe from the outside and not the inside. And the universe has to generate everything itself if you do it from the inside.

• 1:03:19Lee Cronin?

  Assembly theory describes how the universe builds itself.

• 1:03:25Lex Fridman?

  Did it take you 15 seconds to say that?

• 1:03:27Lee Cronin?

  Yeah.

• 1:03:27Lex Fridman?

  Until to come up with that also?

• 1:03:28Lee Cronin?

  No, I've thought of that before.

• 1:03:30Lex Fridman?

  Okay. That's a good line. It's like.

• 1:03:32Lee Cronin?

  Are you making fun again?

• 1:03:33Sara Walker?

  No, I'm not making fun. I'm having fun. There's a difference.

• 1:03:36Lee Cronin?

  Oh, that's good. All right.

• 1:03:37Lex Fridman?

  She's inventing.

• 1:03:38Lee Cronin?

  I'm not all intimidated.

• 1:03:41Lex Fridman?

  And there's a causal history to that fun.

• 1:03:45Lex Fridman?

  You mentioned that there's no way to communicate with aliens until there's overlap in the causal graph.

• 1:03:53Lex Fridman?

  Communication includes being able to see them? And like, what are we? This is the question is, is communication any kind of detection? And if so, what do aliens look like as you get more and more overlap on the causal graph?

• 1:04:12Lee Cronin?

  You're assuming, let's assume that, so when you see them and they see you, you're assuming they have vision, they have the ability to construct in 3D. And in time, there's a lot of assumptions they're making.

• 1:04:24Lex Fridman?

  What detection? All right, let's step back. So yes, okay, you're right. So when, in the English language, when we say the word see, we mean visually, they show up to a party and it's like, oh, wow, that's an alien. That's visual, that's 3D, that's, okay. And that's also assuming scale, spatial scale of something that's visible to you. So it can't be microscopic or it can't be so big that you don't even realize that's an entity. Okay. But other kinds of detection too.

• 1:04:53Lee Cronin?

  I would make it more abstract and go down. I was thinking this morning about how to rewrite the Aracibo message in assembly theory and also to abandon binary. Because I don't think aliens necessarily, why should they have binary?

• 1:05:06Lex Fridman?

  Well, they have some basic elements with which to do information exchange.

• 1:05:11Lee Cronin?

  Let's make it more fundamental, more universal. So we need to think about what is a universal way of making a memory? And then we should re-encode our placebo in that way.

• 1:05:22Lex Fridman?

  What's more basic than zeros and ones?

• 1:05:24Lee Cronin?

  Well, it's really difficult to get out that causal chain because we're so. Let's raise the idea of zero for a moment. It took human beings a long time to come up with the idea of zero. Now, now you've got the idea of zero, you can't throw it away, it's so useful.

• 1:05:36Lex Fridman?

  Discover the idea of zero.

• 1:05:38Lee Cronin?

  To discover or invent.

• 1:05:39Lex Fridman?

  I don't know, but it took a long time, so it was invented, that's right.

• 1:05:43Lee Cronin?

  Yeah, I think zero was invented, exactly. So it's not a given that aliens know what zero is.

• 1:05:49Lex Fridman?

  It's just the one.

• 1:05:51Lee Cronin?

  Massive assumption.

• 1:05:52Lex Fridman?

  It's a useful, it's a useful discovery that you're saying if you break the causal chain, there might be some other more efficient way of representing.

• 1:05:59Lee Cronin?

  That's why I want to meet him and ask him.

• 1:06:02Lex Fridman?

  For a shortcut, but you won't be able to ask him until.

• 1:06:05Lee Cronin?

  What, so I interrupted you and I think you're making a good point. I was just going to say, well, look.

• 1:06:09Lex Fridman?

  Thank you.

• 1:06:10Lee Cronin?

  Sorry.

• 1:06:13Lee Cronin?

  Rather than saying.

• 1:06:13Lex Fridman?

  Please, internet, tweet at him for the rude interruptions. Oh, go ahead, I'm sorry.

• 1:06:17Lee Cronin?

  No, it's okay. Maybe it's change. How do we, so, oh, I don't know what it's like to be an alien. I would like to know.

• 1:06:26Lex Fridman?

  What is the full spectrum of what aliens might look like to us? Now that we've laid this all on, on the table of like, all right, so there has to be some overlap in this causal chain that led to them. What are we, what are we looking for? What do you think we should be looking for? So you met, you mentioned mass spec, measuring certain objects that aliens could create or are aliens themselves.

• 1:06:54Lex Fridman?

  We show up to a planet or maybe not a planet or maybe what, what the, what the hell is the basic object we're trying to measure the assembly index of?

• 1:07:01Lee Cronin?

  Let's cut ourselves a break. Let's assume that they are. They metabolize, they've got an energy source and they're a size that we can recognize. Let's give ourselves a break because there could be aliens that are so big, we won't recognize we're seeing them. There might be aliens that are so small, we don't yet have the ability to, you know, we don't have microscopes that can see, you know, far enough away that just won't be able to see them.

• 1:07:24Lex Fridman?

  So what's a good range?

• 1:07:25Lee Cronin?

  So let's just make a range. Let's just be very anthropocentric and say, we're going to look for aliens roughly our size and technology our size because we know it's possible on Earth, right? I mean, a reasonable thing to do would be to find exoplanets in the same zone as Earth in terms of heat and stuff. And then say, hey, if there's that same kind of gravity, same kind of stuff, we could reasonably assume that the alien life there might use a similar kind of physical infrastructure and then we're good. So then your question becomes really relevant. Say, right, let's use vision, sound, touch.

• 1:08:02Lex Fridman?

  So, okay, that's really nice. So that if there's a lot of aliens out there, there's a good likelihood, if you match to the planet, that they're going to be in the same spatial and temporal, operating in the same spatial and temporal domain as humans. Okay. Within that, what, what did they look like visually? What do they sound like? What do they, oh God, this sounds creepy. Taste like? What do they smell like? Smell like?

• 1:08:35Lee Cronin?

  It sounds like our clubhouse. It was like, can we have sex with aliens? Which was basically me saying.

• 1:08:39Sara Walker?

  Passionate, passionate love.

• 1:08:40Lee Cronin?

  But it wasn't actually about sex. It was about, is our chemistry compatible, right? Is there some?

• 1:08:44Sara Walker?

  Yeah.

• 1:08:45Lex Fridman?

  Yeah. Can we, yeah. Are they edible too? They could be very edible. They could be delicious.

• 1:08:51Lee Cronin?

  That's why I want to see some aliens, right? Because I think, are there, I think, evolution.

• 1:08:58Lee Cronin?

  I mean, evolution exploits symmetry, right? Because why generate memory? Why generate storage? The need for storage space when you can use symmetry? So, and symmetry is quite, maybe quite effective in allowing you to mechanically design stuff, right? So maybe you could be reasonable to assume that aliens could have, they could be bipedal, they could be symmetric in the same way, might have a couple of eyes, or a couple of senses. I mean, we can make that. And perhaps there's this whole zoo of different aliens out there. And we'll never get to be able to classify some of the weird aliens we can't interact with because they are made of such weird stuff.

• 1:09:34Sara Walker?

  Yeah.

• 1:09:34Lee Cronin?

  But we are just going to look at, we're going to find aliens that look most like us. Why not?

• 1:09:39Lex Fridman?

  Because those are the first ones we're likely to see.

• 1:09:41Lee Cronin?

  Yeah.

• 1:09:41Sara Walker?

  Yeah. But I think it's really hard to imagine what the space of aliens is because the space is huge. Because, you know, like, one of the arguments that you can make about why life emerges in chemistry is because chemistry is the first scale in terms of like, you know, building up objects from elementary objects. That the number of possible things that could exist is larger than the universe can possibly make all at once, right? So, so imagine you have two planets and they're cooking some geochemistry. You know, our planet invented one kind of biochemistry. And presumably, as you start building up the complexity of the molecules, the chances of the overlap in those trajectories, those causal chains being built up is probably very low.

• 1:10:23Sara Walker?

  And it gets lower and lower as it gets further advanced along its evolutionary path. So I think it's very difficult to imagine predicting the technologies that aliens are going to have. I mean, it's so, you're looking at basically, planets have kind of convergent chemistry, but there's some variability. And then you're looking basically at the outgrowth into the possibility space of the chemistry.

• 1:10:43Lex Fridman?

  So do you think we would detect the technology, the objects created by aliens, before we detect the aliens?

• 1:10:50Sara Walker?

  Possibly.

• 1:10:51Lex Fridman?

  So when you're talking about measuring Assembly Index, don't you think we would detect the garbage first? Like, at the outskirts of alien civilizations, this is going to be trash?

• 1:11:05Lee Cronin?

  I think I would come back to Arrecibo, the Arrecibo message sent from the Arrecibo telescope built by Drake, I think, and Sagan.

• 1:11:12Lex Fridman?

  How's Arrecibo spelled?

• 1:11:14Sara Walker?

  A R E C I B O.

• 1:11:16Lee Cronin?

  Yes.

• 1:11:16Lex Fridman?

  A R.

• 1:11:17Lee Cronin?

  And there we go, they've got it up there.

• 1:11:18Sara Walker?

  That's the telescope that sent the message that you're talking about.

• 1:11:21Lex Fridman?

  So that message was sent where?

• 1:11:24Lee Cronin?

  It was beamed at a star, a specific star, and it was sent out many years ago. And what they did, so this is why I was pushing on binary, it's a binary message. I think it's a semi-prime length number of characters, so I think 273 by 23, I think. And it basically represents human proton, binary, human beings, DNA, male and female. And it's really cool. But I'm just wondering if it could be done not making any, because it's made assumptions that aliens speak binary. Why make that assumption? Why not just assume that if the difference between physics, chemistry and biology is the amount of memory that's instead,

• 1:12:09Lee Cronin?

  that's recordable by the substrates, then surely the universal thing, my, I'm going to make some sacrilegious statement, which I think is pretty awesome for people to argue with.

• 1:12:21Lex Fridman?

  So this is, we're looking at an image where it's the entirety of the message encoded in binary. And then there's a probably interpretation of different parts of that image. There's a person, there's green parts, it looks like for people just listening, like a game of Tetris. So it's encoding in minimal ways, a bunch of cool information, probably.

• 1:12:44Sara Walker?

  Representing all of us.

• 1:12:45Lee Cronin?

  So the top it's kind of teaching us how to count, and then it all goes all the way down, teaching you chemistry. And then just says, but it makes so many assumptions. And I think if we can actually, so look, I think, I mean, Sarah's much more eloquent in expressing this, but I'll have a go and you can correct it if you want, which is like, one of the things that Sarah has had a profound effect on the way I look at the origin of life, and this is one of the reasons why we're working together, because we don't really care about the origin of life. We want to make life, make aliens and find aliens, make aliens, find aliens. I think we might have to make aliens in the lab before we find aliens in the universe, right? I think that would be a cool way to do it. So what is it about the universe that creates aliens? Well, it's selection.

• 1:13:29Lee Cronin?

  Through assembly theory, creating memories, because when you create memories, you can then command your domain, you can basically do stuff, you can command matter. So we need to find a way, by understanding what life is, of how the minimal way to command matter, how that would emerge in the universe and be if we want to communicate, I mean, maybe we don't want to necessarily uniformly communicate. What I would do perhaps if I had is I would send out lots of probes away from Earth that have this magic way of communicating with aliens, get them quite a far away from Earth, plausibly deniable, and then send out the message that would then attract all the aliens and then basically work out if they're a friend or foe and how they want to hang out.

• 1:14:09Lex Fridman?

  The messages being something that has to do with the memories?

• 1:14:11Lee Cronin?

  Yes, like the the assembly version of our Sebo, so that everyone in the universe that has been understands what life is. So aliens need to work out what they are. Once they've worked out what they are, they then can work out how to encode what they are, and then they can go out and send messages. It's like the universal, the Rosetta Stone for life in the universe is working out how the memories are built. I don't know, Sarah, you have any, well, whether that you'd agree with that?

• 1:14:41Sara Walker?

  No, I I wanted to raise a different point, which is about the fact that we can't see the aliens yet because we haven't gotten the technology. And presumably, we think assembly theory is the right way of doing it, but I don't think that we know how to go from the kind of data you're describing, Lex, like, you know, visual data or smell, to construct the assembly spaces yet. And in some ways, I think that the problem of life detection really is the same problem at the foundations of AI, that we don't understand how to get machines to see causal graphs, to see reality in terms of causation. And so I I think assembly and AI are going to intersect in interesting ways, hopefully.

• 1:15:22Sara Walker?

  But the the sort of key point, and I I've been trying to make this argument more recently. Um, and might write an essay on it is, you know, people talk about the great filter, right? And which is again, this like doomsday thing that, you know, people want to say there's no aliens out there because something terrible happened to them. Um, and it matters whether that's in our, in our, in our past or our future as to the longevity of our species, presumably, which is why people find it interesting. But I think it's not, it's not a physical filter. It's not like things go extinct. I think it's literally, we don't have the technology to see them. Um, and you could see that with microscopes. I mean, we didn't know there were microbes on this table for, or tables for thousands of years or telescopes. Like, there's so much of the universe we can't see. And then basically,

• 1:16:03Sara Walker?

  what we have done as a species is outsource our physical perceptions to technology, building microscopes based on our eyes, um, you know, and building size monitors based on our sense of feelings, like feel earthquakes and things. And AI is basically, we're trying to outsource what's actually happening in our thinking apparatus into machines now and technological devices. And maybe that's the key technology that's going to allow us to see things like us and see the universe in a totally different way.

• 1:16:27Lex Fridman?

  But you kind of mentioned the great filter. Do you think there's a way through technology to stop being able to see stuff? So can you take a step backwards?

• 1:16:34Sara Walker?

  I think so, yeah.

• 1:16:35Lex Fridman?

  Did you imply that with the great, so like?

• 1:16:37Sara Walker?

  Well, no, I mean, I think there's a great perceptual filter in the sense that a, a example of life evolving on a planet over billions of years has to acquire a certain amount of knowledge and technology to actually recognize the phenomena that it is.

• 1:16:53Lex Fridman?

  Well, that's the sense I have is, uh, I mean, you talk with physicists, engineers in general, that there's this kind of idea that we have mo- most of the tools are ready to hear the signal. But to me, it feels like we don't have any of the tools to see the signal.

• 1:17:11Sara Walker?

  Yeah, I agree.

• 1:17:12Lex Fridman?

  That's, that's the biggest, like to hear. We don't have the tools to really hear, to see.

• 1:17:16Sara Walker?

  Yeah.

• 1:17:18Lee Cronin?

  Aliens are everywhere. We just don't have the, the, um, yeah, I'm, well.

• 1:17:23Lex Fridman?

  Well, that's

• 1:17:23Sara Walker?

  I mean, I got this in part, actually, because you were like, you know, last time I was here, he's like, look at the carpet. You know, could it like if you had alien detector where the carpet be aliens? I mean, I think we really don't.

• 1:17:33Lex Fridman?

  I So they would be, but the aliens would nevertheless have a high assembly index or produce things of high assembly index.

• 1:17:39Sara Walker?

  Yeah.

• 1:17:39Lex Fridman?

  Yeah, yeah, yeah. And those things of a high assembly index. You have to have a detector that can recognize high assembly index in all its forms. Yeah.

• 1:17:48Sara Walker?

  Yes.

• 1:17:49Lex Fridman?

  That's it. That's it.

• 1:17:49Sara Walker?

  Take data, construct assembly space.

• 1:17:52Lex Fridman?

  Those patterns, basically, so one way to think about high assembly index is interesting patterns of basic ingredients.

• 1:18:00Sara Walker?

  I can give you an example, because I mean, in molecules, we've been talking about in objects, but we're also trying to do it in spatial trajectories. Like, imagine you're just, like, I always get bothered by the fact that, like, when you look at birds flocking, you can describe that with like a simple Boyd's model, or like, you know, people use spin glass to describe animal behavior. And those are like really simple physics models, yet you're looking at a system that you know has agency and there's intelligence in those birds. And I, and basically, like, you can't help but think there must be some statistical signatures of the fact that there, those are, that's a group of agents versus, you know, like, I don't know, you know, the physics example, maybe like, I don't know, Brownie emotion or something.

• 1:18:42Sara Walker?

  And so what we're trying to do is actually apply assembly to trajectory data to try to say there's a minimal amount of causal history to build up certain trajectories for observed agents as like an agency detector for behavior.

• 1:18:54Lex Fridman?

  Do you think, do you think it's possible to do some like, like Boyd's or those kinds of things? Like, artificial, like cellular tomata, play with those ideas with assembly?

• 1:19:06Lex Fridman?

  With assembly theory? Have you found any useful, really simple mathematical?

• 1:19:13Lex Fridman?

  Like simulation tools that allow you to play with these concepts? So like one, of course, you're doing mass spec in this physical space with, with chemistry. But it just seems, well, I mean, a computer science person, maybe, it seems easier to just

• 1:19:27Sara Walker?

  I agree with you.

• 1:19:28Lex Fridman?

  And sexier in terms of tweeting visual information on Twitter or Instagram, more importantly, to play like, here's an organism of a low assembly index and here's an organism of a high assembly index, and let's watch them create more and more memories and more and more complex objects. And so like, and mathematically, you get to observe what that looks like, to build up an intuition what an assembly index is like.

• 1:19:54Lee Cronin?

  We are building a toolkit right now. So I think it's a really good idea. But what we've got to do is, I'm kind of still obsessed with the infrastructure required. And one of the reasons why I was pushing on information and mathematics, when human beings, when human beings, we take a lot of the infrastructure for granted. And, and I think we have to strip that back a bit for going forward. But you're absolutely right. I would agree that, I think the, the fact that we exist in the universe, this is like, I can see that lots of people would disagree with this statement, but I don't think, I don't think Sarah will, but I don't, I don't know. The fact that objects exist, I don't think anyone on earth can just, will disagree that objects can exist elsewhere, right? But they will disagree that

• 1:20:36Lee Cronin?

  life can exist elsewhere. But what perhaps I'm trying to say is that the, the, the acquisition, the universe's ability to acquire memory is the very first step for building life. And that must be, that's so easy to happen. So therefore, alien life is everywhere, because all alien life is, is those memories being compressed and minimized and the alien equivalent of the cell working. So I think that we will build new technologies to find aliens. But we, we need to understand what we are first and, and how we go from physics to chemistry to biology. The most interesting thing, as you're saying to these two organisms, different assemblies,

• 1:21:20Lee Cronin?

  is when you get into biology, biology gets more and more weird, more and more contingent. Physics is probably, chemistry is less weird because the rules of chemistry are smaller than the rules of biology, and then going all the way to physics where you have a very nicely tangible number of ways of arranging things. And I think assembly theory just helps you appreciate that. And so, once we get there, my dream is that we are just going to be able to suddenly are, I mean, I'm maybe just being really arrogant here. I'm not mean to be arrogant. It's just, again, I've just got this hammer called assembly and everything's a nail. But I think that, once we crack it, we'll be able to use assembly theory plus telescopes to find aliens.

• 1:22:01Lex Fridman?

  Do you have, Sarah, do you have disagreements with Lee on the number of aliens that are out there?

• 1:22:07Sara Walker?

  Do, actually, yeah.

• 1:22:09Lex Fridman?

  And what they look like? So, any of the things we've been talking about, is there nuanced? It's always nice to discover wisdom through nuanced disagreement.

• 1:22:22Sara Walker?

  Yeah, I don't wholly disagree, but I think, but I do think I disagree. It's kind of, there's nuance there. But, but

• 1:22:30Lee Cronin?

  You can disagree.

• 1:22:31Sara Walker?

  No, it's fine. It is nuanced, right? So, you made the point earlier that you think, you know, once we discover what alien, what life is, we'll see alien life everywhere. And I think I agree on some levels, in the sense that I think the physics that governs us is universal. But I don't know how far I would go to say, to say that we're a likely phenomenon, because we don't understand all of the features of the transition at the origin of life, which we would just say in assembly is you go from the no memory physics to, there's like a critical transition around the assembly index where assembliness starts to increase, and that's what we call the evolution of the biosphere and complexification of the biosphere. So, there's a principle of increasing assembliness, where that goes

• 1:23:14Sara Walker?

  back to what I was saying at the very beginning about the physics of the possible, that the universe basically gets in this mode of trying to make as much possibilities as possible. Now, How often that transition happens that you get the kind of cascading effect that we get in our biosphere, I think we don't know. If we did, we would know the likelihood of life in the universe. And a lot of people want to say life is common, but I don't think that we can say that yet till we have the empirical data, which I think you would agree with. But then there's this other kind of thought experiment I have, which I don't like, but I did have it, which is, you know, if life emerges on one planet and you get this real high density of things that can exist on that planet, is it sort of dominating the density of creation that the universe can actually generate? So like, if you're

• 1:23:58Sara Walker?

  thinking about counting entropy, right? Like, the universe has a certain amount of stuff in it. And then, you know, assembly is kind of like an entropic principle. It's not entropy. But the idea is that now transformations among stuff or the actual physical histories of things now become things that you have to count as far as saying that these things exist and we're increasing the number of things that exist. And if you think about that cosmologically, maybe Earth is sucking up all the life potential of the whole universe. I don't know. But I-

• 1:24:28Lex Fridman?

  How's that? Can you explain that a little bit? Why can any one geographical region suck up the creative capacity of the universe?

• 1:24:36Sara Walker?

  Just like, I know, it's a ridiculous thought. I don't, I don't actually agree with it, but it was just a thought experiment.

• 1:24:41Lex Fridman?

  I love that you can have thoughts that you don't like and don't agree with, but you have to think through them anyway.

• 1:24:47Sara Walker?

  Yeah.

• 1:24:48Lex Fridman?

  The human mind is fascinating.

• 1:24:50Sara Walker?

  Yeah, I think these sort of like counterfactual thought experiments are really good when you're trying to build new theories, because you have to think through all the consequences. And there are people that want to try to account for, say, the degrees of freedom on our planet in cosmological inventories of, you know, talking about the entropy of the universe and, you know, and when we're thinking about like cosmological arrow of time and things like that. Now, I think those are pretty superficial proposals as they stand now, but assembly would give you a way of counting it. And then the question is, if there's a certain maximal capacity of the universe's speed of generating stuff, which Lee always has this argument that assembly is about time, the universe is generating more states. Really, what it's generating is more- Assembly possibilities.

• 1:25:31Sara Walker?

  And then dark energy might be one manifestation of that, that the universe is accelerating its expansion because that makes more physical space. And what's happening on our planet is it's accelerating in the expansion of possible things that exist. And maybe the universe just has a maximal rate of what it can do to generate things. And then if if there is a maximal rate, maybe only a certain number of planets can actually do that, or there's a trade off about the pace of growth on certain planets versus others.

• 1:25:57Lex Fridman?

  I have a million questions there, but do you have do you have thoughts on?

• 1:25:59Lee Cronin?

  Just a quick, yeah, I'll just say something very quick.

• 1:26:01Sara Walker?

  It's a thought experiment.

• 1:26:02Lee Cronin?

  No, it's good. I think I get it. I think I get it. So what I want to say is, when I mean aliens are everywhere, I mean memories are the prerequisite for aliens via selection and then concentration of selection when selection becomes autonomous. So what I would love to do is to build, say, a magical telescope that was a memory.

• 1:26:24Sara Walker?

  Magical.

• 1:26:24Lee Cronin?

  A magical one. Yeah, I'm sorry, or a real one. There would be a memory detector to see selection. So you could you could get to exoplanets and say that exoplanet looks like there's lots of selection going on there. Maybe there's evolution and maybe there's going to be life. So what I'm just trying to say is narrow down the regions of space where you say there's definitely evidence of memory as high assembly there, or not high assembly because that would be life, but of select where it's capable of happening. And then with then that would also help us frame the search for aliens. I don't know how likely it is to make the transition to cells and all the other things. I think you're right, but I think that it's.

• 1:27:00Sara Walker?

  Yeah.

• 1:27:01Lee Cronin?

  We just need to get more data.

• 1:27:02Sara Walker?

  Well, I didn't like the thought experiment because I don't like the idea that if the universe has a maximal limit on the amount it can generate per unit time, that our existence is actually precluding the existence of other things.

• 1:27:11Lee Cronin?

  I'll just say one thing.

• 1:27:12Sara Walker?

  But I think that's probably true anyway because of the resource limitations.

• 1:27:14Lee Cronin?

  So I don't I don't like your thought experiment because I think it's wrong. Well, no, no, I do like the thought experiment. So what you're trying to say is like, there is a chain of events that goes back that's manifestly culminated with life on Earth. And you're not saying that life isn't possible elsewhere. You say that there has been these number of things, contingent things that have happened that have allowed life to emerge here. That doesn't mean that life can't emerge elsewhere, but you're saying that these the intersection of events may have maybe concentrated here, right?

• 1:27:43Lee Cronin?

  And I think this.

• 1:27:43Sara Walker?

  Not exactly. It's more like. Like, you know, if you you look at, say, the causal graphs are fundamental, maybe space is an emergent property, which is consistent with some proposals in quantum gravity, but also how we talk about things in assembly theory, then the universe is causal graphs generating more structure in causal graphs, right? So this is how the universe is unfolding. And maybe there's a cap on the rate of generation, like the there's only so much stuff that gets made per update of the universe. And then if there's a lot of stuff being made in a particular region that happens to look the same locally, spatially, that's an after effect of the fact that the whole causal graph is updating. Like, it's it's it's

• 1:28:26Lee Cronin?

  Yeah, I don't I don't know that. I think that that doesn't work.

• 1:28:29Sara Walker?

  I don't think it works either, but I don't have a good argument in my mind about.

• 1:28:32Lee Cronin?

  But I do like the idea of the capacity that you know, because you've got the number of states. Yeah, we can come back to it.

• 1:28:37Lex Fridman?

  Well, let me ask real quick. Like, why does different, like, local pockets of the universe start remembering stuff? How does memory emerge exactly? So at the origin of the universe, it was very forgetful. That's when the physicists were happiest. It was low memory objects, which is like ultra low memory objects, which is what the definition of stuff. Okay. And so how does memory emerge? How does which is this? How does this the temporal stickiness of objects emerge?

• 1:29:15Lee Cronin?

  Um, I I I'm going to take a very chemocentric point of view because I can't imagine any other way of doing it. You you could think of other ways, maybe. But I would say heterogeneity in matter is where the memory. So you must have enough different ways of rearranging matter for there to be a memory. So what that means is if you've got particles colliding in a box, let's just take a some in some elements in a box. Those elements can combine in a commentorial set of ways. So there's a commentorial explosion of the number of molecules or minerals or solid objects, bonds being made. Because there's such a large number, the population of different objects that are

• 1:30:00Lee Cronin?

  possible, this goes back to assembly theory where, assembly theory, there's four types of universes, right? So you've got basically, and this is what one was up earlier, where one universe where you've just got, everything is possible, so you can take all the atoms and combine them and make everything. Then you've got basically, what is the assembly commentorial, where you basically have to accrue information in steps. Then you've got assembly observed, right? And then you've got the object assembly going back. So what that mean, what I'm trying to say is like, if you can take atoms and make bonds, let's say you take a nitrogen atom and add it to a carbon atom, you find an amino acid, then you add another carbon atom on in a particular configuration, then another one,

• 1:30:42Lee Cronin?

  all different molecules, they all represent different histories. So I would say for me right now, the most simple route into life seems to be through recording memories and chemistry. But that doesn't mean there can't be other ways, and can't be other emergent effects. But I think if you can make bonds and lots of different bonds, and they, those molecules can have a causal effect on the future. So imagine a box of atoms, and then, then you combine those atoms in some way, so you make molecule A from a load of atoms, and then molecule A can go back to the box and

• 1:31:22Lee Cronin?

  influence the box, then you make A prime, or AB, or ABC, and that process keeps going, and that's where the memories come from, is that heterogeneity in the universe from bonding. I don't know if that makes any sense.

• 1:31:37Lex Fridman?

  And it's beginning to flourish at the chemistry level.

• 1:31:42Lee Cronin?

  Yeah.

• 1:31:43Lex Fridman?

  So the physicists have no, like, not enough.

• 1:31:48Lee Cronin?

  Yeah.

• 1:31:49Lex Fridman?

  They're like desperately begging for more freedom.

• 1:31:54Lee Cronin?

  Yeah.

• 1:31:55Lex Fridman?

  And heterogeneous components to play with.

• 1:31:59Lee Cronin?

  Yeah.

• 1:32:00Lex Fridman?

  That's exactly it. What do you think about that, Sarah?

• 1:32:03Sara Walker?

  I mentioned already, I think it's significant that whatever physics governs life emerges actually in chemistry. It's not relevant at the subatomic scale or even at the atomic scale. It's in, well, atomic scale because chemistry. But like when you get into this this combinatorial diversity that you get from combining things on the periodic table, that's when selection actually matters, or the fact that some things can exist and others can't exist actually starts to matter. So I think of it like you don't you don't study gravity inside the atomic nucleus. You study it in terms of large scale structure of the universe, or black holes, or things like that. And whatever we're talking about as physics of information or physics of assembly becomes relevant at a certain scale of reality.

• 1:32:48Sara Walker?

  And and the transition that you're talking about, I would think of as just when you get a sufficient density in terms of the assembly space of like the relationship of the overlap and and the assembly space, which is like a feature of common memory, there is this transition to assembly dominated physics, whatever that is. Oh, like when we're talking about. And we're trying to map out exactly what that transition looks like. We're pretty sure, you know, of some of its features, but we haven't done all of that.

• 1:33:16Lex Fridman?

  Do you think if you were there in the early universe, you would have been able to predict the emergence of chemistry in biology? And I ask that because at this stage as humans, do you think we can possibly predict the length of memory that's that might be able to be formed later on in this pocket of the universe? Like, how how complex is a what is the ceiling of assembly?

• 1:33:41Sara Walker?

  I think as much time as you have in the past is how much you can predict in the future. Because that it's actually physical in the system. And you have to have enough time for Uh, but features of that structure to exist.

• 1:33:54Lex Fridman?

  Wait, let me push back on that. Wait, uh, what, isn't that, isn't there somewhere in the universe? That's like a shortest path that's been, that stretches all the way to the beginning.

• 1:34:02Sara Walker?

  Yeah.

• 1:34:03Lex Fridman?

  That's building some giant monster.

• 1:34:05Sara Walker?

  Maybe, yeah.

• 1:34:06Lee Cronin?

  Yeah. So, so you can't predict.

• 1:34:08Sara Walker?

  The universe has as much memory as the largest assembly object in the universe.

• 1:34:11Lee Cronin?

  Yeah.

• 1:34:11Lex Fridman?

  Right. But like, so you can't predict.

• 1:34:14Sara Walker?

  You can't predict any deeper than that. No.

• 1:34:16Lex Fridman?

  Right. So like that, I guess that's all I'm saying is like, what intuition do you have about complexity? Living in the world that you'd have today. Right. Cause you, you just, you can, I mean, I guess how long?

• 1:34:31Sara Walker?

  Well, you couldn't have predicted.

• 1:34:32Lex Fridman?

  Like, isn't there going to be at some point, cause there's a, there's a heat death in the universe. Isn't there going to be a point of the most, uh, of the highest assembly of object at the, with the highest probability being generated?

• 1:34:45Sara Walker?

  When is the universe going to be the most fun and can we freeze ourselves and then live then?

• 1:34:49Lex Fridman?

  Exactly. And will you know when you're having the most fun? That this is the best time you're in your prime? Are you going to do what everyone does, which is deny that you're in your prime and the best years are still ahead of you? I don't.

• 1:35:02Lee Cronin?

  What option do you have? Um, uh, I, I don't, I mean, the problem is with, there's a lots of, lots of really interesting features here. I just want to mention one thing that might be, is I do think assembly theory applies all the way back to subatomic particles. And I also think that cosmological selection might have been actually, there, there might have been, it's not, I would say it's a really boring bit, but it's really important for a cosmologist that, that universes have gone through. Was it Lee Smolin who proposed this? Maybe that there is this, that basically your universe evolves. You've got the wrong constants, we'll start again. And the most productive constants where you can allow.

• 1:35:35Sara Walker?

  Oh, yeah.

• 1:35:36Lee Cronin?

  Particles to form in a certain way, get, propagate to the next universe and we go again. So actually selection goes all the way back and there's these cycles of universes. And now this universe has been selected because, um, life can occur and it's, it carries on. But I'm, I've really butchered that. There is a much more.

• 1:35:52Lex Fridman?

  This is some aspect where through the selection process, there's parameters that are being fine tuned. And we happen to be living in one where there's some level of fine tuning. Is there, given that? Can you still man the case that we humans are alone in the universe? We are the highest assembly index object in the universe.

• 1:36:13Lee Cronin?

  Yeah, I can, I guess. Sad, though. I mean, so from a-

• 1:36:17Lex Fridman?

  Is it possible?

• 1:36:18Lee Cronin?

  Yes, it's possible. Let's assume, well, we know, I mean, it's possible. So let me, so, okay, so there is a particular set of elements on Earth in a particular ratio. And the right gravitational constant and the right viscosity, you know, of stuff being able to move around. The right distance from our sun, right number of events where we have a moon. The Earth is rotating.

• 1:36:49Lee Cronin?

  The late heavy bombardment produced a lot of, brought in the right stuff. And Mars was cooking up, you know, the right molecules first. So it was habitable before Earth. It was literally doing the cometary research. And before Mars kind of became unhabitable, it seeded Earth with the right molecular replicators. And there was just the right stuff on Earth, and that's how the miracle of life occurred. Although I find, I'm very uncomfortable with that because actually, because life came so quickly in the Earth's past. But that doesn't mean that life is easy elsewhere.

• 1:37:34Lee Cronin?

  It just might mean that, because chemistry is actually not a long term thing. Chemistry can happen quickly. So maybe going on with the steel manning of the argument to say, actually, the fact that life emerged quickly doesn't mean that life is easy. It just means that the chemistry was right on Earth, and Earth is very special. And that's why there's no life anywhere else in the universe.

• 1:37:55Lex Fridman?

  Yeah, so Sarah mentioned this kind of cascading thing. So what if that's the reason we're lucky is that we got to have a rare cascading of like accelerating cascading effect in terms of the complexity of things. So like, maybe most of the universe is trying to get sticky with the memory and it's not able to really form it. And then we got really lucky in that. And it has nothing, like, there's a lot of Earth-like conditions, let's say, but it's just, you really, really have to get lucky on this.

• 1:38:30Lee Cronin?

  But I'm doing experiments, I'm doing experiments right now. In fact, experiments that Sarah and I are working on because we have some joint funding for this, where we're seeing that the universe can get sticky really quickly. Now, of course, we're being very anthropocentric, we're using laboratory tools, we're using theory, but actually, the phenomena of selection, the process of heterogen, developing heterogeneity, we can do in the lab. We're just seeing the very first hints of it. And wouldn't it be great if we can start to pin down a bit more precisely, becoming good Bayesianists for this, for the origin of life and the emergence of life, to finding out what kind of chemistries we really need to look for.

• 1:39:13Lee Cronin?

  And I'm becoming increasingly confident we'll be able to do that in the next few years. Make life in the lab, or make some selection in the lab from inorganic stuff, from sand, from rocks, from dead stuff, from moon. Wouldn't it be great to get stuff from the moon, put it in our origin of life experiment and make moon life? And restrict ourselves to interesting self-replicating stuff that we find on the moon.

• 1:39:37Lex Fridman?

  Sarah, what do you think about this approach of engineering life in order to understand life? So building life in the machine?

• 1:39:44Sara Walker?

  Yeah, so, I mean, Lee and I are trying right now to build a vision for a large

• 1:39:52Sara Walker?

  Institute or experimental program, basically, to do this problem. But I think of it as like, we need to simulate a planet. So like, the Large Hadron Collider was supposed to be simulating conditions just after the Big Bang. Lee's built a lot of technology in his lab to do these kind of selection engines. But the question you're asking is, how many experiments do you need to run? What volume of chemical space do you need to explore before you actually see an event? And I like to make an analogy to one of my favorite particle physics experiments, which is super comical conde that's looking for the decay of the proton. So this is something that we predicted theoretically, but we've never observed in our universe. And basically, what they're doing is every time they don't see a proton decay event, they have a longer bound on the lifetime of proton.

• 1:40:36Sara Walker?

  So imagine we built an experiment with the idea in mind of trying to simulate planetary conditions, physically simulate. You can't simulate original life in a computer. You have to do it in an experiment. Simulate enough planetary conditions to explore the space of what's possible and bound the probability for an original life event, even if you're not observing it, you can talk about the probability. But we, hopefully, life is not exponentially rare. And we would then be able to evolve in an automated system, alien life in the lab. And if we can do that, then we understand the physics as well as we understand what we can do in particle accelerators.

• 1:41:16Lex Fridman?

  So keep expanding physically the simulation, the physical simulation, until something happens.

• 1:41:23Sara Walker?

  Yeah, or just build a big enough volume of chemical experiments and evolve them.

• 1:41:27Lex Fridman?

  You say volume, you mean like literally volume?

• 1:41:29Sara Walker?

  I mean, uh, physical volume in terms of space, but I actually mean volume in terms of the combinatorial space of chemistry.

• 1:41:36Lex Fridman?

  So how do you nicely control the combinatorial exploration, the search space? Such that it's always like? You keep grabbing the low hanging fruit.

• 1:41:47Sara Walker?

  Yeah. How do you build a search engine for chemistry?

• 1:41:49Lee Cronin?

  I think you explained it very well. We should carry on doing this. I should pretend to be the physicist. You be the chemist. No. So the way to do it is, I will always play a joke because I like writing grants to ask for money to do cool stuff. And years ago, I started wanting to build. So I actually wanted to weather. So I built this robot in my lab called the Chemputer, which is this robot you can program to do chemistry. Now it's a pro. I made a programming language for the Chemputer and made it operate chemist, chemical equipment. Originally, I wrote grants to say, hey, I want to make an origin of life system. And no one would give me any money for this. They said, what? This is ridiculous. Why are you wanting to make it? It's really hard. It takes forever.

• 1:42:35Lee Cronin?

  You're not a very good origin of life chemist anyway. Why would we give you any money? And so I turned it around and said, can you can instead, can you give me money to make robots, to make molecules? Oh, interesting. And everyone went, yeah, okay, you can do that.

• 1:42:49Lee Cronin?

  And that's so actually, the funny thing is the Chemputer

• 1:42:54Lee Cronin?

  project, which I have in my lab, which is very briefly, it's just basically, it's like literally an automated test tube. And we've made a programming language for the test tube, which is cool.

• 1:43:04Lee Cronin?

  Has come, is literally came from this. I went to my lab one day and said, I want to make a search engine to get the origin of life because I don't have a planet. And I thought about doing it in a microfluidic format. So a microfluidic is very nano, very small channels in device where you can basically have all the pipes lit done, produced by lithography. And you can have a chamber, maybe say between, say 10 and 100 microns in volume. And we slot them all together like Lego and we can make an origin of life system. And I could never get it to work. And I realized I had to make, do chemistry at the kind of test tube level. And what you want to be able to do, yeah, it goes back to that tweet, nineteen eighty one.

• 1:43:45Lex Fridman?

  Nineteen eighty one, the computer, we're looking at a tweet from Lee. In nineteen eighty one, the computer was a distant dream. And, oh, wow, this is the scientist looking back at his, the young boy who dreamed. In two thousand and eighteen, it was realized, spelled in a British way, realized.

• 1:44:04Lee Cronin?

  Yeah, I'm starting to all said, but not.

• 1:44:06Lex Fridman?

  So now there's a system that does the physical manifestation, or whatever the programming language, the spec tells you to do.

• 1:44:16Lee Cronin?

  Yeah, well, in nineteen eighty one, I got my first computer, ZX eighty one.

• 1:44:19Lex Fridman?

  What was the computer?

• 1:44:20Lee Cronin?

  ZX eighty one.

• 1:44:21Lex Fridman?

  ZX eighty one.

• 1:44:23Lee Cronin?

  Sinclair ZX eighty one. It was, and I got a chemistry set. And I like, I like the chemistry set, and I like the computer, and I just wanted to put them together. I thought, wouldn't it be cool if I could use the computer to control the chemistry set? And, and obviously, that was insane. And I was like, you know, you know, eight years old, right? Nine years old, going on nine years old. And, and then I, I, I invented the computer just because I wanted to build this origin of life grid, right? Which is like, literally a billion test tubes connected together in real time and real space, basically throwing a chemical die, dice, throw dice, throw dice, throw dice. You're gonna get lucky.

• 1:45:05Lee Cronin?

  And that's what we, I think Sarah and I have been thinking very deeply about, because, you know, there's more money being spent on the, the, the origin of the gravity or looking at the Higgs boson than the origin of life, right? And the origin of life is the, I think, the biggest question, or not the biggest question, it is a big question, let's put it that way.

• 1:45:26Sara Walker?

  It is the biggest question. You're okay saying that.

• 1:45:28Lee Cronin?

  Okay.

• 1:45:28Lex Fridman?

  Well, isn't it possible, once you figure out the origin of life, that that's not going to solve, that's not actually gonna solve the question of what is life? Like, is, isn't, because you're kind of putting a lot of.

• 1:45:41Sara Walker?

  Yeah, I think that's the same problem.

• 1:45:43Lex Fridman?

  But you're, you're putting, is it possible that you're putting too many? Too much bets into this origin part, maybe the origin thing isn't, isn't there always a turtle underneath the turtle? Isn't there a stack of turtles? Cause then if you create it in the lab, maybe you need some other stuff.

• 1:46:00Lee Cronin?

  Well, let's not think about the.

• 1:46:01Lex Fridman?

  Like you, you, like in the lab, there's still memory.

• 1:46:06Sara Walker?

  Yeah, yes.

• 1:46:07Lex Fridman?

  Right?

• 1:46:07Sara Walker?

  The experiment is already the product of evolution.

• 1:46:10Lex Fridman?

  Right, in some maybe really deep way, not an obvious way, in some very deep way.

• 1:46:14Sara Walker?

  Yeah.

• 1:46:15Lex Fridman?

  So maybe the haters are always going to be like, well, you have to reconstruct the fold, you have to build it from scratch.

• 1:46:22Sara Walker?

  Fortunately for us, the haters are not aware of that argument.

• 1:46:25Lex Fridman?

  Well, no, I know, I just.

• 1:46:27Sara Walker?

  We're the one making that argument usually, but yeah.

• 1:46:30Lex Fridman?

  I, I just think that if we create life in the lab, it's not obvious that you'll get to the deep, deep understanding of necessarily. What is the line between life and non-life?

• 1:46:42Lee Cronin?

  No, I think so. There's so much here.

• 1:46:43Lex Fridman?

  I'm just like playing devil's.

• 1:46:45Lee Cronin?

  So much here, but let me play devil's advocate back in a previous conversation, right? And say, um, uh, yeah, I will, why not? Why not? We've got time.

• 1:46:54Lex Fridman?

  Let's go.

• 1:46:54Lee Cronin?

  Cellular meter.

• 1:46:56Lex Fridman?

  Yes.

• 1:46:56Lee Cronin?

  Cellular meter, these, these very, very simple things where you color squares, um, black or white, and implement rules and play them in time. And you can get these very, very complex patterns coming out. You know, there's nice rules, they're churing complete rules and, um, and, um, I would argue that so automata are the, are, don't really exist on their own. They have to exist on a, in a computing device. If that, whether it's computing device is a piece of paper and abstraction, a mathematician drawing a grid, or, um, a, a, a framework. Now, so I would argue CAs are beautiful things, simple going complex, but the complexity is all borrowed from the lithography, the numbers.

• 1:47:42Lee Cronin?

  Right, now let's take that same argument with the, um, the chemistry experiment origin of life.

• 1:47:49Lee Cronin?

  Cat, what you need to be able to do is go, and I'm inspired to do this, to go out and look for CAs occurring in nature. You know, let's kind of, let's find some, um, some CAs that just emerge in our universe and-

• 1:48:03Lex Fridman?

  For people just to interrupt, for people just listening and in general, I think what we're looking at is a cellular automata where again, as Lee described, there is just binary black or white squares and they only have local information and they, they're born and they die. And you would think nothing interesting would emerge, but actually what we're looking at is something that I believe is called glider guns, uh, or, or a glider gun, which is, uh, moving objects in this multi-cell space that look like they're organisms that have much more information, that have much more complexity than the individual

• 1:48:43Lex Fridman?

  building components. In fact, look like they have a long-term memory. Uh, while, while the individual components don't seem like they have any memory at all.

• 1:48:52Lee Cronin?

  Yes. The argument here is, um, that has to exist on all this layer of infrastructure, right? And though it looks simple. And then what I would make, the argument I would make if I were you, say, well, I think CAs are really simple and everywhere, is say, show me how they emerge in a substrate. Now let's go to the origin of life where, or machine. I don't think we, we want to do the origin of life, just any origin is good. So we do, so we literally have our sand shaker, shake the sand, like massive grid of chemistry experiments, shaking sand, shaking whatever. And then because we know what we've put in, so we know where, how we've cheated. And the same way with CA, we know how we've cheated, we know what the micro, we know the number of operations needed, we know how big a grid we want to

• 1:49:32Lee Cronin?

  get this. If we could then say, okay, how can we, um, generate this recipe in the lab and make a life form? What were the, what contingency did we need to put in? And we're upfront about how we cheated. Okay, say, oh, you had to shake it. It was a periodic planet rotates. It's tried, comes in and out. So, and then we can start to basically say, okay, how difficult is it for these features to be found? And then we can look for extra planets and other features. So I think Sarah is absolutely right. We want to explain to people we're cheating. In fact, we have to cheat. No one has given, I'm, I'm good at writing grants. I used to be, I'm not very good right now. I keep getting rejected, but I, writing a grant for a planet in a hundred million years,

• 1:50:16Lee Cronin?

  no grant fund there is going to give me that. But maybe money to make a, a kind of a grid, a computer grid. Origin of life computer grid.

• 1:50:24Lex Fridman?

  In physical space.

• 1:50:25Lee Cronin?

  In physical space and just do it.

• 1:50:28Lex Fridman?

  So Sarah said something, which is you can't simulate the origin of life in a, in a computer. So like in simulation, why not? What, what, what are your, you said it very confidently. So.

• 1:50:41Sara Walker?

  Yeah.

• 1:50:42Lex Fridman?

  Is it possible? And why would it be very difficult? Like, what's your intuition there?

• 1:50:47Sara Walker?

  I think it's very difficult right now because we don't know the physics. But if you go based on principles of assembly theory and you think every molecule is actually a very large causal graph, not just the molecule, then you have to simulate all the features of those causal graphs. And I think it becomes computationally intractable. You might as well just build the experiment.

• 1:51:05Lex Fridman?

  Because you have, in the physical space, you have all the objects with all the memories.

• 1:51:10Sara Walker?

  Yes.

• 1:51:10Lex Fridman?

  You, in, in the computer, you would have to.

• 1:51:13Sara Walker?

  Yes.

• 1:51:13Lex Fridman?

  Copy them or reconstruct.

• 1:51:14Sara Walker?

  Yes.

• 1:51:15Lee Cronin?

  Yeah. That's a beautifully put. And I would say that lots of people, you, you, you just don't have enough resources. It's, it's, it's easier to actually do the physical experiment because the, we are literally, I would view the physical experiment almost like a computational experiment. We're just outsourced, it's just basically, we're just outsourcing all the matrix.

• 1:51:36Sara Walker?

  And on your point about the experiment being also an example of life, it's almost like you want to design, it's like, you know, all of us are lineages of propagating information across time. And so everything we do becomes part of life because it's part of that causal chain. So it's like, you want to try to pinch off as much as you can of the information from your causal chain that goes into the experiment, but you can't pinch off all of it to move it to like a different timeline. It's always going to be part of your timeline. But at least if you can control how much information you put in, you can try to see how much does that particular trajectory you've set up start generating its own assembly? So you, you, you know where it starts. And then you want to try to see it take off on its own when you've tried to pinch it off as much as possible.

• 1:52:21Lex Fridman?

  Got it. Quick pause, bathroom break.

• 1:52:24Sara Walker?

  Yes.

• 1:52:24Lex Fridman?

  All right, cool. And now we're back. All right. We talked about the early days of the universe when there was just stuff and no memory, not even causality. I think Lee at least implied the causality is immersion somehow. We could discuss this. What happened before this all originated? What's outside the universe?

• 1:52:49Lee Cronin?

  Divided by zero.

• 1:52:51Lex Fridman?

  Okay, so it's not, it's not relevant, not understandable. Is it useful to even ask the question?

• 1:52:57Lee Cronin?

  No.

• 1:52:58Lex Fridman?

  To just, because it's so hard?

• 1:53:01Lee Cronin?

  No, it's not hard. It's just not a question. If I can't do an experiment or even think of experiment, the question doesn't exist.

• 1:53:08Lex Fridman?

  Well, no, you can't think of a lot of experiments. No offense.

• 1:53:13Lee Cronin?

  What I mean is I can't.

• 1:53:14Lex Fridman?

  Because your causality graph is like, this is what we've been talking about. It's like, there is limits to your ability to construct experiments.

• 1:53:24Lee Cronin?

  I agree, but I'm, I'm, I was trying to be facetious and I'm trying to make a point is I think that if you, if there is a.

• 1:53:33Lee Cronin?

  Causal bottleneck through which information can't propagate in principle, then it's very hard to ask, to think of an experiment, even in principle, even one that's beyond my mediocre intellect, right? Which is fine, I'm happy to accept that. But this is one of the things, I actually do think there was something before the Big Bang. Because I would say that I think the Big Bang just couldn't occur and create time. Time created the Big Bang.

• 1:54:00Lex Fridman?

  There was time before the Big Bang.

• 1:54:02Lee Cronin?

  Yeah.

• 1:54:03Lex Fridman?

  There was no space, but there was time.

• 1:54:04Lee Cronin?

  Yeah. Yeah. But, I mean, I'm just making that stuff up just to make all the physicists happy. But I think it's.

• 1:54:11Lex Fridman?

  Do you think that would make them happy? Because they would be quite upset, actually.

• 1:54:14Lee Cronin?

  And why would they be upset?

• 1:54:16Lex Fridman?

  Because they would say that time can't exist before the Big Bang.

• 1:54:20Lee Cronin?

  Yeah, I mean, this goes back to an argument that you might not want to have the argument here. I was talking to Sarah earlier today about an argument we had about time a long time ago. A long time in time. And what I would, is like, I think there is this thing called time or state creation. The universe is creating states and it's outside of space, but they create space. So what I mean is, you can imagine there are states being created all the time. And there is this thing called time, time is a clock, which you can use to measure when things happen. But that doesn't mean, because you can't measure something, that states aren't being created. And so you might locally refer to the Big Bang.

• 1:55:01Lee Cronin?

  And the Big Bang occurs at some point in, when those states were there. Probably there had to be enough states for the Big Bang to occur. And then, but I think that there is something wrong with our conception of how the universe was created in the Big Bang, because we don't really get time. Because again, you know, I don't want to become boring and sound like a broken record. But, but time is a real thing. And until I can really explain that more elegantly, I'm just going to get into more trouble.

• 1:55:33Lex Fridman?

  We're going to talk about time, because time is a useful measuring device for experiments, but also time is an ideal, all that, okay. But let me first ask Sarah, is like, what do you think? Is it a useful question to ask what happened before the Big Bang? Is it a useful question to ask what's outside the universe?

• 1:55:53Sara Walker?

  So I would think about it as the Big Bang is an event that we reconstructed as probably happening in the past of our universe, based on current observational data. And so the way I like to think about it is we exist locally in something called a universe. So, and going back to like the physics of existence, we exist locally in the space of all things that could exist. And we can infer certain properties of the structure of where we exist locally. And one of the properties that we've inferred in the past is that there is a thing we call the Big Bang. There's some signatures of our local environment that indicate that there was a very low information event that started our universe.

• 1:56:38Sara Walker?

  I think that's actually just an artifact of the structure of the assembly space that when you when you start losing all the memory in the objects, it it looks like what we call a Big Bang. So I think it makes sense to talk about where you are locally. I think it makes sense to talk about counterfactual possibilities, what could exist outside the universe, in the sense that they become part of our reasoning and therefore part of our causal chain of things that we can do. So like the multiverse in my mind exists, but it doesn't exist as a multiverse of possible universes. It exists as an idea in our minds that allows us to reason about how physics works and then to do physics differently because we reason about it that way.

• 1:57:21Sara Walker?

  So I always like to re-center it on things exist, but they don't always exist like we think they exist. So when we're thinking about things outside the universe, they absolutely exist because we're thinking about them. But they don't look like they don't look like the projections in our minds. They're something else.

• 1:57:39Lee Cronin?

  Something you said just gave an idea to go back to your question. If.

• 1:57:45Lee Cronin?

  There was, I mean, if something caused the Big Bang, if there was some memory or some artifact of that, then of course, to answer your question, it's worth going back to that because that would imply there is something beyond that barrier, that filter.

• 1:57:58Sara Walker?

  Yeah.

• 1:57:58Lee Cronin?

  And that's what you were saying, I guess.

• 1:57:59Sara Walker?

  Right. I'm agnostic to what exists outside the universe. I just don't think that. Like, I think the most interesting things for us to be doing are finding explanations that allow us to do more, like, that optimism. So I tend to draw the boundary on questions I ask as being scientific ones because I find that that's where the most creative potential is to impact the future trajectory of what we're doing on this planet.

• 1:58:22Lex Fridman?

  It's interesting thing about the Big Bang is basically from our current perspective of what we're able to detect, it's the time when things were forgotten.

• 1:58:31Sara Walker?

  Yes.

• 1:58:33Lex Fridman?

  It's the time of the reset, from our limited perspective. And so the question is, is it useful to ever study the thing that was forgotten? Or should we focus just on the memories that are still there?

• 1:58:47Lee Cronin?

  Well, the point I was trying to make about the experiment is I was trying to say both things. And I think perhaps, yes, from the pot-falling point of view, if you could then imagine what was forgotten and then work forwards, you will have different consequences. So then it becomes testable. So as long as we can find tests, and it's definitely worth thinking about. What I don't like is when physicists say, what happened before the Big Bang and before, before, before, without giving me any credible conjecture about what we would, how would we know the difference? But the way you framed it is quite nice. I like that. It's like, what have we forgotten?

• 1:59:22Lex Fridman?

  Is there a room for God in assembly theory? Who's God?

• 1:59:28Sara Walker?

  I like arguments for a necessary being better than God.

• 1:59:31Lee Cronin?

  Well, I think I said it earlier.

• 1:59:33Lex Fridman?

  What's a necessary being?

• 1:59:33Sara Walker?

  Like, something that has to exist.

• 1:59:37Lex Fridman?

  Oh, so you like, I mean, you like the shortest path? Like, does God need?

• 1:59:41Sara Walker?

  No, no, I, I, I mean, I, well, you can go back to like Thomas Aquinas and arguments for the existence of God, but I think, I think most of the interesting theological arguments are always about whether something has to exist, or there was a first thing that had to exist. But I think there's a lot of logical loopholes in those kind of arguments.

• 1:59:58Lex Fridman?

  Well, so God here, meaning the machine that creates, that generates the stuff.

• 2:00:08Lee Cronin?

  But God, so what I was trying to say earlier is-

• 2:00:10Sara Walker?

  Isn't that just the universe then?

• 2:00:11Lee Cronin?

  Yeah, yeah.

• 2:00:12Lex Fridman?

  Well, yeah, well, but I, there's a difference between, I, I sort of, I imagine like a black box, like a machine.

• 2:00:19Sara Walker?

  Yeah.

• 2:00:19Lex Fridman?

  That's, then I would be more comfortable calling that God. Because it's a machine. You go into a room and there's a thing with a button.

• 2:00:26Sara Walker?

  Yeah, I don't like the great programmer in the sky version.

• 2:00:28Lee Cronin?

  Can I?

• 2:00:29Lex Fridman?

  Yeah, but if it's more kind of a, um, like, I don't like to think of, if you look at a cellular automata,

• 2:00:38Lex Fridman?

  if it, if it's the cells and the rules, that doesn't feel like God, that generates a bunch of stuff. But if there's a machine, like a, that does, that runs the cellular automata and set the rules, then that feels like God. That, the sort of, in terms of terminology. So I wonder if there's like a machine that's required to generate this universe. That's very sort of important for running this in the lab.

• 2:01:05Lee Cronin?

  So as I said earlier, I think I said this earlier, that, I can't remember the phrase, but something like, I mean, does God exist in our universe? Yes. Where does God exist? God at least exists in abstraction in my, in our minds. Particularly a people who have, who have religious faith they believe in. But let's then take your, but you're talking a little bit more about generics, say, well, is there a mechanism beyond the universe you're calling God? I would say God did not exist at the beginning, but he or she does now. Because I'm saying the-

• 2:01:39Lex Fridman?

  Well, you don't know if he didn't exist in the beginning. So like, uh, this could be us in our minds trying to recall, like, just what, listening to gravitational waves, detecting gravitational waves. It's the same thing, us trying to, uh, go back further and further into our memories to try to understand the machines that make up.

• 2:02:01Lex Fridman?

  To make up us. And so it's possible that we're trying to grasp at possible kind of, what kind of machines could create? There's, there's always a tweet. There's always a tweet. If the universe is a computer, then God must have built it because computers need creators. There you go.

• 2:02:22Lex Fridman?

  And then, uh, Yoshua Bach replied, since there's something rather than nothing, perhaps existence is the default.

• 2:02:31Lex Fridman?

  If existence is the default, then many computers exist. Creator gods are necessary computers, unnecessarily computers too. I'm very confused by that, but that's an interesting idea that existence is a default versus non-existence.

• 2:02:44Lee Cronin?

  I agree with that, but the rest is.

• 2:02:46Lex Fridman?

  Leave response, perhaps this reasoning is incomplete. That's, that's how scientists talk trash each other on Twitter, apparently. Which part don't you agree with?

• 2:02:57Lee Cronin?

  When he said, if existence is default, then many computers exist. This comes back to the inventor and discovery argument. I would say the universe at the beginning wasn't capable of computation because there wasn't enough technology, enough states. So what you're saying is the, if God is a mechanism. So I might actually agree, but then the thing is lots of people see more, see God is more than a mechanism. For me, God could be the causal graph in assembly theory that creates all the stuff and the memories we know. And the fact that we can even relate to each other is because we have the same, we share that heritage. And why we love each other or we like to see God in each other is, it's just,

• 2:03:40Lee Cronin?

  we can, we can, we know we have a shared existence.

• 2:03:43Lex Fridman?

  So if the God is the mechanism that created this whole thing, I think a lot of people see God, you know, in a religious sense, as a, as that mechanism also being able to communicate with the objects it creates. And if it's just the mechanism, we won't be able to create with the object, uh, communicate with the objects it creates. It can only create, it can't like. Interact with the.

• 2:04:07Sara Walker?

  There's versions of God that create the universe and then left, you know.

• 2:04:12Lex Fridman?

  Yeah, like spark.

• 2:04:13Sara Walker?

  For some religions, but.

• 2:04:15Lex Fridman?

  The first spark, yeah.

• 2:04:16Sara Walker?

  Yeah, but I think I liked your analogy of the machine and the rules, right? But I think part of the problem is you, I mean, we have this conception that we can disentangle the rules from the physical substrate, right? And that's the whole thing about like software and hardware being separate, or the way Newton wrote his laws, that there was some, you know, like they exist outside the universe. They're not actually a feature of the universe. They don't have to emerge out of the universe itself.

• 2:04:42Sara Walker?

  So I think if you, if you merged your two views, then it gets back to the God is the universe. And then I think the, the deeper question is, why does it seem like there's meaning and purpose? And if I think about the features of the universe that give it the most meaning and purpose, those are the, what we would call the living components of the universe. So if you wanted to say God is a physically real thing, which you were saying is like an emergent property of our minds, but I would just say, you know, the way the universe creates meaning and purpose, there is really a physics there. It's not like a illusory thing, and that is just what, what the physics of life is.

• 2:05:17Lex Fridman?

  Is it, is it possible that we've forgotten much of the mechanisms that created the universe? So like, so basically, you know, whatever, if God is that mechanism, we just leave parts of that behind.

• 2:05:31Sara Walker?

  Well, but the universe is constantly generating itself. So if God is that mechanism, it would be that, that would still be active today. I don't, like, I'm agnostic, but if I, if I, if I recall, recall the things I believe in God and the way that some people talk about God, I would say that God is, you know, like in the, like universe now, it's not an absent thing.

• 2:05:53Lee Cronin?

  Are you, I'm, so I think there's a mislabeling here because you're, I mean, I mean, I'm.

• 2:06:02Lee Cronin?

  Professional idiot, um, actually, but, but.

• 2:06:06Lex Fridman?

  You should put that on your CV.

• 2:06:08Sara Walker?

  Yeah.

• 2:06:09Lee Cronin?

  Yeah.

• 2:06:09Lex Fridman?

  Professionally, not recreationally or amateur, but professionally.

• 2:06:13Lee Cronin?

  But I think. I would say if you were talking about God, I mean, again, I'm way out, way out of my depth here. And I almost feel uncomfortable. Yeah, but I feel quite uncomfortable articulating, but I'll try. For me, a lot of people that think of God as a consciousness, a reasoning entity that actually has causal power. And you're.

• 2:06:32Sara Walker?

  Human like intelligence.

• 2:06:33Lee Cronin?

  And you're, and so you're like, then you're saying like, gravity could be God or time could be God. I mean, I think for me, for my conception of time is probably as fundamental as God, because it gave rise to human intelligence and consciousness in which we can have this abstract notion of God. So I, I, I think that you, you're maybe talking about God in a very mechanistic, kind of unsophisticated sense, whereas other people say that God is more sophisticated and got all this, you know, feelings and love and, you know, and this abstracting ability. So is that what, or do you mean that? Do you mean God as in this conscious entity that decided to flick the universe into existence?

• 2:07:15Lex Fridman?

  Well, one of the features that God would have is the ability to flick the universe into existence. I, you know, like Windows 95, I don't know if God is Windows 95 or Windows XP or Windows 10. I don't know the full feature set.

• 2:07:34Lee Cronin?

  Okay.

• 2:07:34Lex Fridman?

  So you, the very least, you have to flick the universe into existence. And then other features might include ability to interact with that universe in interesting ways. And then how do you interact with the universe in interesting ways? You have to be able to speak the language of its different components. So in order to interact with humans, you have to, um, know how to act human like.

• 2:08:03Lex Fridman?

  So, so I don't, I don't know.

• 2:08:07Lex Fridman?

  But it seems like whatever mechanism created the universe might want.

• 2:08:16Lex Fridman?

  To also generate local pockets of mechanisms that can interact with that.

• 2:08:21Lee Cronin?

  Could make a joke.

• 2:08:22Lex Fridman?

  Inject.

• 2:08:24Sara Walker?

  God was lonely?

• 2:08:25Lex Fridman?

  Yeah, it was lonely. I mean, it could be just a teenager and another, just playing a video game.

• 2:08:30Lee Cronin?

  Maybe. Well, I was gonna say, I mean, I, I don't, so this is referring to our origin of life engine. It's like, I don't believe in God, but that doesn't mean I don't want to be one.

• 2:08:40Lex Fridman?

  Right.

• 2:08:41Lee Cronin?

  Because I want to make a universe and make a life form, but that maybe, that may be rude to people who have, you know, their religious beliefs. What I mean by that is, isn't, if we are able to create an entirely new life form, different chemistry, different culture,

• 2:08:58Lee Cronin?

  what does it make up and makes us good? By that definition, it makes us gods, right?

• 2:09:02Lex Fridman?

  Well, there is. I mean, like, when you have children, you're like, one of the magical things of that is you're kind of mini gods. I mean, first of all, from a child's perspective, parents are gods for quite a while. And then, I mean, they're, they're, in the positive senses, there's a magic to that. That's why I love robotics, is you instill life into something. And that makes you feel godlike in a sort of positive way.

• 2:09:29Sara Walker?

  Being a creator is a positive thing, yeah.

• 2:09:31Lex Fridman?

  Creator. Yeah, exactly. And a small scale. And then God is, would be a creator at the largest possible scale, I suppose. Okay. You mentioned offline, the Assembltron.

• 2:09:44Lee Cronin?

  Assemblytron.

• 2:09:45Lex Fridman?

  Assemblytron.

• 2:09:46Lee Cronin?

  Yep.

• 2:09:47Lex Fridman?

  What, what's an assemblytron? These are the, this is an early idea of something you're thinking about.

• 2:09:51Lee Cronin?

  So Sarah's team, well, I think Sarah's team are interested in using AI to understand life, my team is. And I'm, and I'm think, wondering if we could apply the principles of assembly theory, that is,

• 2:10:06Lee Cronin?

  the causal structure that you get with assembly theory, and hybridize it and make a new type of neuron, if you like. I mean, there are causal neural networks out there, but they are, they are not quite the architecture like what I would like. I would like to associate memory bits with, basically, I'd like to make a, rather than having an ASIC for neural networks, I want to make an ASIC for assembly networks, right? And.

• 2:10:35Lex Fridman?

  So can you say that again? Assembly networks.

• 2:10:39Lex Fridman?

  So what, what is a, so like a? A thing with an input and an output and it's like a neural network type of a thing. What does it do exactly? What's the input? What's the output?

• 2:10:48Lee Cronin?

  So in this case, so if you're talking about a general neural network, I mean, in general neural network, you can train it on also any sort of data, right? Depending on the the framework, whether it's like text or or image data or whatnot. And that's fine, but there's no causal structure associated with that data. Now, just imagine, rather than, you know, let's say when to classify the difference between cat and dog, right? Classic cat and dog neural network. What about if the system understood the assembly space that created the cat and the dog? And rather than guessing what was happening and training on those images and not understanding

• 2:11:29Lee Cronin?

  those features, it you almost like you could imagine doing a going back a step and doing and and training, going back a step and doing the training, going back a step, back a step, back a step. And and I wonder if that is actually the origin of intelligence or how we'll crack intelligence, because we need to because we'll we'll create the entire graph of events and and be able to kind of look at cause and effect across those graphs. I'm explaining it really badly, but it's it's a gene of an idea. And I'm guessing very smart, very rich people in AI are already doing this.

• 2:12:07Lex Fridman?

  Trying to not generate cats and dogs, but trying to generate things of high assembly index.

• 2:12:13Lee Cronin?

  Yeah. And I think I think and also using causal graphs in neural networks and machine learning and deep learning, maybe building a new architecture. I'm just wondering, is there something we can get out of assembly theory allows us to rebuild current machine learning architectures to give more give causation more cheaply? I mean, I don't know if that's what you we've been inventing this for a little while, but we're trying to finish the theory paper first before we do anything else.

• 2:12:40Sara Walker?

  Yeah, you also want to have, say, goal directed behavior in neural networks. Then assembly theory is a good framework for doing that. Daniel's been thinking about that a lot.

• 2:12:49Lee Cronin?

  Yeah.

• 2:12:49Sara Walker?

  And I think it's a really interesting idea that you can map concepts from how neural networks learn to thinking about goal directed behavior as a learning process, that you're learning a specific goal. The universe is learning a goal when it generates a particular structure and that you can map that physical structure in a neural network.

• 2:13:08Lex Fridman?

  What's the goal?

• 2:13:10Sara Walker?

  Well, in a neural network, you're designing the goal in biology. I mean, you know, people are not supposed to use teleological language in biology, which is ridiculous, but because goals are real things. They're just post-selected. So you can talk about goals after the fact. You know, once a goal emerges in the universe, that physical entity has a goal. But Lee and I came up with a test for like a Turing test for goal-directed behavior based on the idea of assembly. Like, we have to formalize this still, but I would like to write a paper on it. But like, the basic idea is like, if you like, if you had two systems that were completely equivalent, you know, like in the instantaneous, like, physical experimental setup.

• 2:13:55Sara Walker?

  So Lee has to figure out how to do this. But there was something that would be different in their future. And there was a symmetry breaking you observe in the present based on that possibility, that future outcome, then you could say that that system had some representation of some kind of goal in mind about what it wanted to do in the future. And I so so goals are interesting because they don't exist as instantaneous things. They exist across time, which is one of the reasons that assembly theories may be more naturally able to account for the existence of goals.

• 2:14:27Lex Fridman?

  So goals are they only exist in time or they manifest themselves in time through, you said symmetry breaking?

• 2:14:37Sara Walker?

  So it's almost like, imagine like, if representations in your mind are real, right? And you can imagine future possibilities, but imagine everything else is physically equivalent. And the only thing that you actually change your decision based on is what you model as being the future outcome. Then somehow that representation in your mind of the future outcome becomes causal to what you're doing now. So it's kind of like retrocausal effect. But it's not actually retrocausal. It's just that your your assembly space is actually includes those possibilities as as part of the structure. It's just you're not observing all the features of the assembly space in the current moment.

• 2:15:15Lex Fridman?

  Well, the possibilities exist, but they don't become. A goal until they realize.

• 2:15:21Sara Walker?

  So, so one of the features of assembly space is super interesting and it's easier to envision with like Legos, for example, is if you're thinking about an assembly space, you can't observe the entire assembly space in any instant in time. So if you imagine a stack of Legos and you want to look at the assembly space of a stack of Legos, you have to break the Legos apart and then you look and then you look at all the possible ways of building up the original object. So now you have in your mind the goal of building that object and you have all the possible ways of doing it and those are actual physical features of that object, but that object doesn't always exist. What exists is the possibility of generating it.

• 2:15:56Lex Fridman?

  Right, and the possibilities are always infinite.

• 2:15:59Sara Walker?

  Uh, well, for that particular object, you know, like, you know, it has a well-defined assembly space. And I guess what I'm saying is that object is the assembly space, but you actually have to unpack that object across time to view that feature of it. It's only an observable across time.

• 2:16:14Lee Cronin?

  The term goal is such a important and difficult to explain concept, right? Because what you want is a way is like, um, I think only conscious beings can have conscious goals. Everything else is doing selection and but selection does invent goals and in a way that um, the, the way that biology reinterprets the past in the present is kind of helps you to understand there was a goal in the past now, right? It's kind of like goals only exist back in time.

• 2:16:48Lex Fridman?

  So, first of all, um, only conscious beings can have conscious goals. I'm not even gonna touch that one.

• 2:16:58Lee Cronin?

  Why, why, why?

• 2:16:59Lex Fridman?

  Well.

• 2:17:00Lee Cronin?

  Go for it, come on.

• 2:17:01Lex Fridman?

  Well, the line between conscious goals and uh, non-conscious goals, exactly. Right? And also maybe just on top of that, you said a Turing test for goal-directed behavior. What's, what's, what's, what's the Turing, what, what does a Turing test potentially look like?

• 2:17:18Lee Cronin?

  So if you've got two objects, we were thinking about this. So we, we, we actually got some funding to work to go on two teams. So I'm trying to do, and part of this is I'm trying to do a bit of theory and Sarah's teaching me a bit of theory and Sarah's trying to design experiments and I'm teaching experiments. Cause I think it's really good for us to have that to say, um, when would a

• 2:17:37Lee Cronin?

  So that's good. I like this. I'm sure we're using Dan Dennett essay.

• 2:17:40Sara Walker?

  Yeah, and I can explain why we wouldn't want to call it a Turing test after.

• 2:17:44Lee Cronin?

  Yeah, so Dan Dennett wrote this really nice essay about herding cats and free will inflation.

• 2:17:51Sara Walker?

  The title is so brilliant.

• 2:17:52Lee Cronin?

  That's the actual title.

• 2:17:53Sara Walker?

  That's the title, yeah.

• 2:17:54Lee Cronin?

  Herding cats and free will inflation. Yeah, something like that. I mean, it's not maybe not. And so.

• 2:17:59Sara Walker?

  No, I think that's right.

• 2:18:00Lee Cronin?

  So if you've got a, let's imagine you've got two objects on a hillside. Okay, and this happens to be a snowy hill. And let's just say you see an object go rolling down the hill. Or you, and the rock goes down hill, but the start goes to the end. How do you know the object's had a goal? Now you unveil the object and you'll see it's actually a skier. And the skier starts at the top and goes down the bottom. Great. Then you look at the rock. Rock rolls down the hill, gets to the bottom. How can you tell the difference between the two? So, and what Dan says is like, well, this is clear the skier is in control. And because they're adjusting the trajectory, so some updating going on. Then the only way you could really do that is if you had to put the skier back to the top of the hill again.

• 2:18:43Lee Cronin?

  They tend to start roughly in the same space and probably go to take all that complex set of trajectories and end up pretty much at the same finish point, right? With plus or minus a few meters, whereas if it was just a random rock going down to a random trajectory, that wouldn't happen. And so what Sarah and I were kind of doing when we were writing this grant, we were like, we need to somehow instantiate the skier and the rock in the experiment. And then say, okay, when is the object, when it, so for an object to have a goal, it has to have an update, it has to have some sensing and some kind of, you know, inbuilt actuation to respond to the environment. And, and then we just have to iterate on that. And maybe Sarah, you can then fill in the Turing test part.

• 2:19:26Sara Walker?

  Well, yeah, I guess the motivation for me was slightly different. So I get really frustrated about conversations about consciousness as most people do. You know, and a lot of people are, which is not necessarily related to free will directly or to this goal-directed behavior, but I think there's a whole set of bundled and related topics here. But I think for me, I was, you know, everybody's always interested in explaining intrinsic experience and quantifying intrinsic experience, and there's all sorts of problems with that. Because you can never actually be another physical system, so you can't know what it's like to be another physical system. So I always thought there must be some way of getting at this problem about. If an agent or an entity is conscious, or at least has internal representations,

• 2:20:07Sara Walker?

  and those are real, physical things, that there it must have causal consequences. So the way I would ask the question of consciousness is not, you know, what is it like intrinsically? But if if things have intrinsic experience, is there any observable difference from the outside about the the kind of causation that that physical system would enact in? And for me, the most interesting thing that humans do is have imagination. So like, we can imagine rockets centuries before we build them. They've become real, physical things because we imagine them. And people might disentangle that from conscious experience, but I think a lot of the sort of imagination we do is actually a conscious process. So then this becomes a question of if I were observing systems and I said, one had

• 2:20:51Sara Walker?

  an internal representation, which is slightly different than a conscious experience, obviously. So I'm entangling some concepts, but it's a loose set of thought experiments. Then how and I and I set them up in a physically equivalent situation. Would it be the case that there would be experimental observables associated with it? And that that became the idea of trying to actually measure for internal representation or consciousness. So Turing basically didn't want to do that. You just wanted a machine that could emulate and trick you into having the behavior, but never dealt with the internal experience because he didn't know how to do that. And I guess I was wondering, is there a way to set up the experiment where you could actually test for that?

• 2:21:36Lex Fridman?

  For imagination that led to the

• 2:21:39Sara Walker?

  That there was something internal going on, some kind of inner world, as people say, but I or you could say, you know, like, it actually is an agent. It's making decisions. It has an internal representation. And whether you say that's experience or not is a different thing. But at least the the feature that there's some abstraction it's doing that's not obvious from looking at the physical substrates.

• 2:22:02Lex Fridman?

  Do you think it's possible to do that kind of thing? One of the compelling things about the Turing test is that, you know, defining intelligence, defining any complicated concept as

• 2:22:13Lex Fridman?

  As a thing, like observing it from the surface and not caring about what's going on deep inside, because how do you know?

• 2:22:21Lee Cronin?

  That's the point. So the idea is exactly that. So what we're trying to do, the Turing test for goal directedness is literally take some objects that clearly don't have any internal representation, grains of sand blowing on the beach or something, right? And I don't know, a crab wandering around on the beach and then generating an experiment where we literally, the experiment generates an entity that literally has no internal representation, it's a sand, like these are oil droplets, actually, what I've got in mind, a robot that makes oil droplets. But then what we want to try and do is train the oil droplets to be like crabs, give them an internal representation, give them the ability to integrate information from the environment. So they understand, they remember

• 2:23:03Lee Cronin?

  the past, are in the present and can imagine a future. And in a very limited way, their kind of game engine, their limited simulation of the world allows them to then make a decision.

• 2:23:17Sara Walker?

  They're objects across time.

• 2:23:19Lex Fridman?

  So then you would run a bunch of crabs, like over and over and over and over?

• 2:23:23Sara Walker?

  How many crabs, Lee?

• 2:23:24Lex Fridman?

  How many, is there, what's, because you have to have a large number of crabs. What is, what is your theory say? Is there a mathematical?

• 2:23:31Lee Cronin?

  We're working on it. I mean, this is literally-

• 2:23:33Lex Fridman?

  Limit, crab limit.

• 2:23:34Lee Cronin?

  There's literally a-

• 2:23:36Sara Walker?

  Excellent.

• 2:23:36Lee Cronin?

  There's literally-

• 2:23:37Lex Fridman?

  What's the herding cats have to do? Oh, that's random? Wait, what's cats in the title by Daniel Dennett, Herding Cats and the Free Will Inflation?

• 2:23:45Lee Cronin?

  So-

• 2:23:46Lex Fridman?

  What does herding cats mean? What does free will inflation mean?

• 2:23:49Lee Cronin?

  So this, I love this essay because it explained to me how I can live in a deterministic universe, but have, not free will, but have freedom, you know, and also it helped me explain that the time needed to be a real thing in this universe. So what basically Dan was saying here is like, how do you, how do, these cats appear to just do what they want? Right? And if you live in a deterministic universe, why do the cats do these things? You know, aren't they just, isn't it all obvious? Um, and how does free will inflate the universe? And for me, I mean, probably I love the essay because my interpretation of the essay in assembly theory makes complete sense.

• 2:24:35Lee Cronin?

  Um, because you need an expanding universe in assembly theory to create novelty that you search for that then, when you find something interesting and you keep doing it because it's cool and it gives you an advantage, then it appears in the past to be a goal.

• 2:24:54Lex Fridman?

  So what, what does in assembly theory, the expansion of the universe look like? What, what are we, what are we talking about? Why is, why, why does the expansion of the universe give you more possibilities of novelty and cool stuff?

• 2:25:09Lee Cronin?

  So for me, I don't think about the universe in terms of big bang and space. I think about it in terms of the big, the big memory expansion that you have one, you only have the ability to store one bit of information, so then you can't do very much. So what the universe has been doing since the, since forever, it's been creating more, it's been increasing the size of its RAM. Okay, so it's like one megabyte, two megabyte, three megabyte, four megabytes, all the way up. And so the more RAM you have, the more you can remember about the past, then which allows you to do cooler things in the future. So if you can remember how to launch a rocket, then you might be able to imagine how to land a rocket and then relaunch, re-land and carry on.

• 2:25:53Lee Cronin?

  And because, and so the, the, you able, you're able to expand the space and remember the past. And so that's why I think it's very important.

• 2:26:02Lex Fridman?

  But not a perfect memory. It's, it's a, it's an interesting question whether there's some forgetting that happens and might increase. Is the expansion of the forgetting at some point accelerate faster than the remembering?

• 2:26:16Lee Cronin?

  I think that that's a very important thing that probably intelligence does and we're going to learn in machine learning about because you want machine learning right now or artificial intelligence right now doesn't have memory, right? But you want the ability to, or not for, if you want to get to human-like consciousness, you need to have the ability, I suppose, to remember stuff and then to selectively forget stuff so you can re-remember it and compress it. Arguably, the way that we come up with new physical laws. Yeah, sorry, you were.

• 2:26:44Sara Walker?

  No, no, it's all right. No, I just wanted to.

• 2:26:46Lee Cronin?

  I think that there is a great deal to be gained from having the ability to remember things, but then, when you forget them, you can then have a, you can basically do the simulation again and work out if you get to that compressed representation. So that is in cycles. So cycles of remembering and forgetting are probably important, but there shouldn't be excuse to have a universe with no memory in it. The universe is going to remember that it forgot, but just not tell you.

• 2:27:19Lex Fridman?

  I'm looking at this paper and it's talking about a puppet controlling a puppet controlling a puppet controlling a puppet controlling a puppet controlling a puppet. Conceptually easy to understand, but physically impossible. It's physically impossible. It's predicting a fair coin toss. I don't know what he's talking about, but there's pictures of puppets controlling puppets. Let me ask you, there's a few things I want to ask, but we brought up time quite a bit. You guys tweet about time quite a bit. What is time in all of this? We kind of mentioned it a bunch. Is it not important at all in terms of, is it just a word? Should we be talking about causality mostly? Like, so what do you think? We've talked about like memories. Is that the fundamental thing that we should

• 2:28:04Lex Fridman?

  be thinking about? And time is just a useful measurement device or something like that?

• 2:28:09Sara Walker?

  Well, there's different concepts of time, right? So I think in assembly theory, when we're talking about time, we're talking about the ordering of things. So that's the causal graph part. And so then the fundamental structure of the universe is that there is a certain ordering and certain things can't happen until other things happen. But usually when we colloquially talk about time, we're talking about the flow of time. And I guess Lee and I were actually debating about this this morning. So in talking on it, walking on the river here, which is a very lovely spot for talking about time. But that, you know, when the universe is updating, it's transitioning between. Things that exist now and things that exist now. That's really the flow of time. So there's, there's, you have to separate out those concepts at bare minimum.

• 2:28:54Sara Walker?

  And then there's also an arrow of time that people talk about in physics, which is that time doesn't appear to have a directionality in fundamental physics, but it does to us, right? Like, we can't go backwards in time. And usually, we, you know, that would be explained in physics in terms of, well, there's a cosmological arrow of time, but there's also the thermodynamic arrow of time of increasing entropy. But what we would say in assembly theory is that there is a clear directionality, the universe only runs in one direction, which is why some things, it's easy to make, if the universe runs in one direction, it's easy to make processes look reversible. For example, if they have no memory, they're easy to run forward and backwards, which is why the laws of physics that we have now look the way they do, because they involve objects that have no memory. But when you get to things like us, it becomes very clear that the universe has a directionality

• 2:29:39Sara Walker?

  associated to it.

• 2:29:40Lex Fridman?

  So it's not reversible at all? It's the, no man ever steps in the same river. I just have to bring that up because you want to.

• 2:29:46Sara Walker?

  Yeah.

• 2:29:47Lex Fridman?

  No man ever steps in the same river twice, for it's not the same river and he's not the same man. So that it's not reversible, any of this.

• 2:29:55Sara Walker?

  No, no, but reversibility is an emergent property, right? So we think of the reversibility laws as being fundamental and the irreversibility as being emergent. But I think what we would say, from how we think about it, and certainly it's easy to get the case for our perception of time, but also, you know, what's happening in biological evolution, you can make things reversible, but it requires work to do it. And it requires certain machines to run it forward and backward. And Chiara Marletto is working some interesting ideas on constructor theory related to that, which is a totally different set of ideas.

• 2:30:24Lex Fridman?

  So you can travel back in time sometimes?

• 2:30:28Sara Walker?

  Yes. You could reconstruct, not, you can't travel actually back in time, but you could reconstruct things that have existed in the past. You're always moving forward in time, but you can cycle through, like, I mean, I can...

• 2:30:40Lee Cronin?

  Can I clarify what you just said?

• 2:30:41Sara Walker?

  Yeah, yeah, go for it.

• 2:30:42Lee Cronin?

  Quickly, you travel forward in time to travel back?

• 2:30:45Sara Walker?

  Yes.

• 2:30:46Lex Fridman?

  That, thank you, that really clarified it.

• 2:30:47Lee Cronin?

  Well, no, what Sarah's saying is you don't go back in time, you recreate what happened in the past in the future and inspect it again.

• 2:30:54Lex Fridman?

  So in that local pocket of time, it's as if you travel back in time. So I don't, how's that not traveling back in time?

• 2:31:01Lee Cronin?

  Because you're not going back to your same self back in time. You are, you're creating that in the future.

• 2:31:06Lex Fridman?

  But everything else is the same as it was in the past.

• 2:31:08Lee Cronin?

  No, no, no, no, it's not in registry. I mean, it goes back to the big question. I'm saying, I mean, this is something I, I was trying to look up today when I first, we first had this discussion and I was talking to Sarah on Skype and said, by the way, time is, time is the fundamental thing in the universe. She almost hung up on me.

• 2:31:26Sara Walker?

  Right, but, but you can even, I mean, if you want to make an analogy to computation, and I think Charles Bennett actually has a paper on this, like about reversible computation and reversible Turing machines. In order to make it reversible, you have to store memory to run the process backwards. So time is always running forward in that. Because you have to write the memory.

• 2:31:44Lex Fridman?

  You can't erase the memory.

• 2:31:45Sara Walker?

  You can erase the memory, but the point, when you go back to zero, right? But the whole point is that in order to have a process that even runs in both directions, you have to start talking about memory to store the information to run it backwards.

• 2:32:00Lex Fridman?

  I got it. So you, you can't really then, you can't have it exactly how it was in the past.

• 2:32:06Lee Cronin?

  Yeah, you, exactly.

• 2:32:07Lex Fridman?

  You have extra stuff, extra baggage always.

• 2:32:09Lee Cronin?

  A really important thing that I want to say on this, I think if I try and get it right, is to say that if you can think that the universe is expanding in terms of the number of boxes that it has to store states, right? And this is where the directionality of the universe comes from, everything comes from. You could erase what's in those boxes, but the fact you've now got so many boxes at time now in this present, there's more of those boxes than there were in the past.

• 2:32:36Lex Fridman?

  See, but the boxes aren't physical boxes. They're not space, it's not space or time. So why, why is the number of boxes always expanding?

• 2:32:44Lee Cronin?

  It's very hard to imagine this because we live in space. So what I'm saying, which is, I think, probably correct, is that we just, let's just imagine for a second. There is a non-local situation, but there are these things called states. And the universe, irrespective of whether you measure anything, there is a universal, let's call it a clock or a state creator. Maybe we can call, that's why, maybe you can call it God, but let's call it a state creator, where the universe is expanding in the number of states it has.

• 2:33:20Lex Fridman?

  Why are you saying it's expanding though? Is that obvious that it's expanding?

• 2:33:23Lee Cronin?

  It's obvious because that's where the, because we, we.

• 2:33:27Lex Fridman?

  That's a source of novelty.

• 2:33:29Lee Cronin?

  It's a source of novelty and it also explains why the universe is not predictable.

• 2:33:34Lex Fridman?

  How do you know it's not predictable?

• 2:33:35Lee Cronin?

  Well, it's.

• 2:33:36Lex Fridman?

  I just like interrupting you. So it's fun because you're struggling.

• 2:33:40Lee Cronin?

  I'm struggling because it's, but I'm trying to be as concrete as possible and not sound like I'm insane.

• 2:33:45Lex Fridman?

  Yeah.

• 2:33:46Lee Cronin?

  And I'm not insane. It's, it's obvious because you did. Um, I'm a chemist, so as a chemist, I grew into the world, understanding irreversibility. All irreversibility is all I knew. And when people start telling me the universe is actually reversible, it's a magic trick. We can use time to do it. So what I mean is the, the, the second law is really the magical. But why does it need to be magical? The universe is just asymmetric. All I'm saying is the universe is asymmetric in the state production. And we can erase those states, but we just have more computational power.

• 2:34:29Lee Cronin?

  So what I'm saying is that the universe's deterministic horizon, this is one of the reasons we can't live in a simulation, by the way.

• 2:34:38Lex Fridman?

  The.

• 2:34:39Lee Cronin?

  You can't live in a simulation.

• 2:34:40Lex Fridman?

  The irreversibility?

• 2:34:41Lee Cronin?

  Yeah. So basically every time you try and simulate the universe and you know, I live in a simulation, the universe has expanded in states. You're like, oh damn it, I need to make my computer bigger again. And every time you try and contain the universe in the computation, because it's got bigger in number of states. And so I'm saying. The fact that the universe has novelty in it is going to turn out experimentally to be proof that time, as I've labeled it, is fundamental and exists as a physical thing that creates space.

• 2:35:13Lex Fridman?

  Okay, so if you can prove that novelty is always being created, you're saying that it's possible to also then prove that it's always expanding in the state space. Those are things that to be, have to be proven.

• 2:35:27Lee Cronin?

  That's what we're working on experiments for, yeah.

• 2:35:29Lex Fridman?

  And you're trying to, like, by looking at the sliver of reality, show that there's always novelty being generated.

• 2:35:35Lee Cronin?

  Yeah, because if we go and live in a universe that the conventional physicists would live in, it's a big lookup table of stuff and everything exists. I want to prove that that book is, that book doesn't exist, it's continuously being added pages on. So all I'm saying, if the universe is a book, we started, the universe at the beginning only had no pages and had, or had one page, another page, another page, whereas a physicist would now say all the pages exist and we could in principle access them. I'm saying that is fundamentally incorrect.

• 2:36:06Lex Fridman?

  Do you know what's written in this book, the free will question? Is there room for free will in this, in this, in this view of the universe is generating novelty and getting great and greater assembly structures built, Sarah?

• 2:36:25Sara Walker?

  Yes.

• 2:36:27Lex Fridman?

  Okay.

• 2:36:27Sara Walker?

  Done. Next question.

• 2:36:29Lex Fridman?

  Why, what's the source of free will in this?

• 2:36:32Sara Walker?

  Well, so I think it depends on what you mean by free will. But.

• 2:36:37Lex Fridman?

  Yeah, well, please.

• 2:36:39Sara Walker?

  I think, I think what I'm interested in as far as the phenomena of free will is, do we have individual autonomy and agency? And, you know, when I do things, is it really me or is it my atoms that did it? And that's the part that's interesting to me. I guess there's also the determinism versus randomness part. But the way I think about it is like each of us are like a thread or like an, you know, assembly space through, you know, this, this giant possibility space and it's like we're moving.

• 2:37:15Sara Walker?

  On our own trajectory through that space and that is defined by our history. So we're sort of causally contingent on our past. But also because of the sort of intersection of novelty generation. It's not completely predetermined by the past. And so, so then you have the causal control of the determinism part. That you are your causal history and there's some determinism from that past. But there's also room for creativity. And I think it's actually necessary that something like free will exists. If the universe is going to be as creative as possible. Because if I were an all intelligent being inventing a universe.

• 2:37:57Sara Walker?

  And I wanted it to have maximal number of interesting things happen. Again, we should come up with the metric of interesting. But generating, yes, I know. Generating, you know, maximal possibilities. Then I would want the agents to have free will because it means that they're more individual, like they are, like each entity actually is a different causal force in the universe. And it's intrinsic and local property of that system.

• 2:38:25Lex Fridman?

  There's a greater number of distributed agents. Like are you always creating more and more individuality?

• 2:38:33Sara Walker?

  Kind of. I would say you're creating more causal power, but.

• 2:38:37Lex Fridman?

  So causal power, the word consciousness, is the causal power somehow correlated with consciousness?

• 2:38:44Sara Walker?

  I mean, that's why I have this conception of consciousness being related to imagination. Because the more that we can imagine can happen and the more counterfactual possibilities you have in mind, the more you can actually implement. And somehow free will is also at the intersection of the counterfactual becoming the actual.

• 2:39:00Lex Fridman?

  So can you elaborate on that a little bit that consciousness is imagination?

• 2:39:04Sara Walker?

  I don't know exactly how to articulate it. And I'm sure people will take, you know, aim at certain things I'm saying. But I think the language is really imprecise. So I'm not the best way to.

• 2:39:13Lex Fridman?

  It's really, it's really interesting. Like what is imagination and what is it? What role does it play? In the human experience, in experience of any agent.

• 2:39:24Sara Walker?

  Yes, I love imagination. I think it's like the most amazing thing we do. But I guess one way I would think about it is, we talked about the transition to life being the universe acquiring memory and life does something really interesting. Just think about biology generally. It remembers states of the past to adapt to things that happen in the future. So, so the longer life has evolved on this planet, the deeper that past is, the more memory we have, the more kinds of organisms and things. But what human level intelligence has done is quite different. It's not just that we remember states that the universe has existed in before, it's that we can imagine ones that have never existed and we can actually make them come into existence. And I think that's the most unique feature about the transition to whatever we are from what life on this planet has been

• 2:40:08Sara Walker?

  doing for the last four billion years.

• 2:40:10Lee Cronin?

  And I think-

• 2:40:11Sara Walker?

  And I think it's deeply related to the phenomenon we call consciousness.

• 2:40:13Lee Cronin?

  Yeah, I was gonna, I mean, just agree with that. I think that consciousness is the ability to generate those counterfactuals. Now, whether you can say, you know, are there degrees of consciousness? I mean, and I mean, I'm, I'm sorry, panpsychist, but electrons don't have counterfactuals, although they do have some kind of, they are able to search a space and pathways. But, but I think that there is a very concrete, or concrete, there's a very specific property that humans have, and I'm, and I don't know if it's unique to humans. I mean, maybe dogs can do it and, and, and birds can do it, right? And where they are basically solving a problem, because consciousness was invented, or this abstraction

• 2:40:54Lee Cronin?

  was invented by evolution for the, for a specific reason. And so, look, the, one of the reasons why I came to the conclusion that time was fundamental was actually because Sarah and I had completely different-

• 2:41:09Sara Walker?

  The most heated debate on Skype chat ever.

• 2:41:11Lee Cronin?

  No, no, no, we had to-

• 2:41:12Lex Fridman?

  On which topic?

• 2:41:14Lee Cronin?

  No, I, no, it goes back to the free will thing. So I, I think the, although I've changed my view a bit, because there's some really interesting physicists out there who talks about how the measurement problem in, in, in Newtonian space, I don't want to go there just now, because I think I'll mess it up. But briefly, I could not see how the universe, how we can have free will. And I mean, this is really boring, because this is like, this is a well-trodden path, but I'll, but I mean, not so boring. I suppose it's kind of, we just want to be precise. If the universe is deterministic, how can we have free will? Right? So, Sarah's a physicist. I think she believe, not believe can show that the most of the laws we have are deterministic to some degree, quantum mechanics on to Newtonian stuff.

• 2:41:59Lee Cronin?

  And yet there's Sarah telling me she believes in free will. I'm like, your belief system is broken here, right? Because you you're demanding free will in a deterministic universe. And and then I've realized that I agreed with her that I do think that free will is a thing because we are able to search for novelty. And then that's where I came to the conclusion that time, universe is expanding in terms of novelty. And it goes back to that Dan Dennett essay that we're talking about, the free will inflation, free will. So you are, you have, so the past, it did not exist in the past, the past exists in the present. What I mean is like, you are the, there was no past, there is only present.

• 2:42:41Lee Cronin?

  So that means you are the sum total, everything that occurs in the past is manifestly here in the present. And then you have this little echo state in your consciousness because you're able to, you're able to imagine something without actualization. But the fact you imagine it, that occurs in electrons and potassium ion flows in your neural network in your brain.

• 2:43:03Sara Walker?

  Maybe consciousness is just the present.

• 2:43:05Lee Cronin?

  So so somehow you imagine that. And then by imagining, oh, that's good. Yeah, I'm going to make a robot that do this thing and program it. And then you physically then go and do it. So that then changes the future. Sorry.

• 2:43:20Lex Fridman?

  What's imagination? Does it require the past? Does it require the future? Does it require memory? Does it?

• 2:43:28Lee Cronin?

  Yes, imagination.

• 2:43:29Lex Fridman?

  Does it only exist in the moment?

• 2:43:32Lee Cronin?

  So imagination is, well, yeah, probably it's an instantaneous readout of what's going on. You can maybe your subconscious brain has been generating all the, all the bits for it. But no, imagination occurs when you, in your game engine, you you remember the past and you integrate sensory the present and you try and work out what you want to do in the future. And then you go and make that happen. So the imagination is this, it's like, imagine, asking what imagination is about, asking what surfing is. You can see, you can surfboard, surfer, wave coming in. When you're on that wave and you're surfing. That's where the imagination is.

• 2:44:10Sara Walker?

  I think imagination is just accessing things that aren't the present moment in the present moment. So like I'm sitting here and I'm looking at the table and I can imagine the river and things, or whatever it was. And so it seems to be that it's like it's our ability to access things that aren't present.

• 2:44:29Lex Fridman?

  But to conjure up worlds, some of them might be akin to something that happened to you recently.

• 2:44:36Sara Walker?

  Right, but they don't have to be things that actually happened in your past. And I think this gets back to assembly theory. Like, the way I would think about imagination from an assembly theoretic standpoint is I'm a giant causal graph. And I exist in a present moment as a particular configuration of Sarah. But I carry a lot of evolutionary baggage. I have that whole causal history and I can access parts of it. Now, when you talk about getting to something as complex as us, having as large an assembly space as us, there's ways of, like, there's a lot of things in that causal graph that have actually never existed in the past history of the universe, because the universe got

• 2:45:15Sara Walker?

  big enough to contain the three of us in this room in time. But not all the features of each one of us individually have come into existence as physical objects we would recognize as individual objects. This goes back to your point that we actually have to explain why things actually even look like objects and aren't just a smear of mass. And just on the free will and physics thing, when you were talking, I just want to bring this up because I think it's a really interesting viewpoint that Nicholas Jizin has, that, you know, we want to use the laws of physics and then say you can't have free will. And his point is, you have to have free will in order to even choose to set up an experiment to test the laws of physics. So in some sense, free will should be more fundamental than

• 2:45:59Sara Walker?

  physics is, because to even do science, there's some assumption that the agents have free will. And I always thought it was really perplexing that, you know, physics wants to remove agency, because the idea that I could do an experiment here on this part of Earth, and then I can move somewhere else and prepare an identically-prepared experiment, run an experiment again, seems to imply something about the structure of our universe that is not encoded in the laws that we're testing in those experiments.

• 2:46:28Lex Fridman?

  So this kind of dream of physics that you can do multiple experiments, different locations, and then validate each other, you're saying that's, that's an illusion?

• 2:46:37Sara Walker?

  No, I'm saying that requires decision making and free will to be a real thing, I think. Like, I think that, I think the fact that we can do science is not arbitrary. And I think people, you know, the standard canon in physics would be, well, you could trace all of that back to the initial condition in the universe. But the, the whole point of science is I can imagine doing the experiment and I can do it. And then I can do it again and again and again all over the planet.

• 2:46:59Lex Fridman?

  Do you imagination somehow fundamentally generative of novelty?

• 2:47:03Sara Walker?

  Yes.

• 2:47:04Lex Fridman?

  So it's not like the universe could have predicted the things you imagined?

• 2:47:07Lee Cronin?

  Imagination, so coming back to novelty, I think novelty can exist outside of imagination, but it's supercharged. It's another transition, I think. I mean, I would say, I mean, this may be a boring statement, but I would say the fact that-

• 2:47:19Sara Walker?

  I'm not sure. It's a hard, these are hard questions.

• 2:47:21Lee Cronin?

  Yeah, I mean, I think the fact that objects exist is yet another proof that, that time is fundamental and novelty exists, right? Because I think, again, if you ask a physicist to write down an infinite bible of the universe, let's call it the bible, the, the ma, you know-

• 2:47:37Sara Walker?

  That book?

• 2:47:37Lee Cronin?

  Yeah, well, I mean, I mean-

• 2:47:38Sara Walker?

  That book that we're on pages to-

• 2:47:39Lee Cronin?

  The mathematical universe, whether you're Max Tegmark or Sean Carroll or Frank Wilczek or, or Stephen Wolfram, okay?

• 2:47:49Lex Fridman?

  Yeah.

• 2:47:49Sara Walker?

  I like that book.

• 2:47:51Lex Fridman?

  Yeah, I love it too. Lots of pretty pictures.

• 2:47:53Lee Cronin?

  It's really interesting that they, they cope with the enormity of the universe by saying, well, it's all there mathematics, it all exists, right? And, and I would say that that's why I'm excited about the future of the universe, because it, it, although it is somehow dependent upon the past, it is not constrained just by the past, which is kind of mad.

• 2:48:17Lex Fridman?

  Yeah, that's what free will is. It's not constrained by the past. It's dependent on the past. This moment, it's not just dependent, this moment is the past, and yet it has the capacity to generate a totally unpredictable future.

• 2:48:31Lee Cronin?

  I mean, the other thing I would say is super important for human beings, right? Human beings have actually very little causal control in the future. I realized this the other week.

• 2:48:41Sara Walker?

  Oh, then maybe it's your dream.

• 2:48:42Lee Cronin?

  Yeah, yeah. So what happened, so this is what I think it is. The way, by reinterpreting your past, I mean, talk about from a kind of cognitive, psychological cognitive point of view, by reinterpreting your past-

• 2:48:55Lee Cronin?

  In your current mind, you could actually help you shape your future again. So you but you you have much more freedom to interpret your past, to act in the present, to change your future than you do to change your future. I may sound weird, so I'm saying, everybody, imagine your past, think about your past, reinterpret your past in the nicest way you can, then imagine what you can do next, or imagine your past in a more negative way and what you do next. And look at those two counterfactuals, they're different.

• 2:49:24Lex Fridman?

  Yes, that's I mean, Daniel Kahneman talks about this, that most of our life is lived in our memories. It's interesting because you can essentially in imagination, choose the life you live. So maybe free will exists in imagination. Choices are made in your imagination. And that results in you basically able to control how the future unfolds. Because you're like imagining, like reinterpreting constantly the things that happen to you.

• 2:49:50Lee Cronin?

  Exactly. So you there, if you want to increase your amount of free will, those people that have most, I don't think everyone has equal amounts of agency because of because of our sad sad constraints, whether whether, you know, happenstance, health, economic, born in born in a certain place, right? But you're those of us that have the ability to go back and reinterpret our past and and and use that to change the future are the ones that exert most agency in the present. And I I want to I want to achieve higher degrees of agency and enable everyone else to do that as well, to have more fun in the universe.

• 2:50:30Sara Walker?

  Then we'll hit that peak. The maximum fun.

• 2:50:33Lee Cronin?

  I don't think there's ever going to be a maximum. I think it's the wonderful thing about the future is there's always going to be more fun.

• 2:50:39Lex Fridman?

  Yeah, you, I think, again, going back to to Twitter, I think you tweeted something about being a life maximalist, that you want to maximize the number of life, the the amount of life in the universe. So and, you know, that's the more general version of that goal is to maximize the amount of fun in the universe, because life is a subset of fun. There are all kinds of, I suppose they're either correlated or exactly equal. I don't know. Anyway, speaking of fun, let me ask you about alien sightings.

• 2:51:11Lex Fridman?

  So there's been quite a bit of UFO sightings and all that kind of stuff. What do you think would be the first time when humans cite aliens, see aliens in a sort of unquestionable way? This extremely strong and arguable way? We've made contact with aliens. Sarah, what would it look like? Obviously, the space of possibility is huge here, but if you were to kind of look into the future, what would that look like? Would it be inklings of UFOs here and there that slowly unravel a mystery?

• 2:51:52Lex Fridman?

  Or would it be like an obvious overwhelming signal?

• 2:51:57Sara Walker?

  So I think we have an obsession with making contact with events. So what I mean by that is, you know, like, people have a UFO sighting, they make contact. And I always think, you know, what's interesting to me about the UFO narratives right now is not that I have a disbelief about what people are experiencing or feeling, but like the discussion right now is sort of at the level of modern mythology. Aliens are our mythos in modern culture. And when you treat it like that, then I want to think about when do things that we traditionally only regularize through mythology actually become things that become standard knowledge?

• 2:52:39Sara Walker?

  So, you know, like, it used to be, you know, variations in the climate were described by some kind of gods or something. And now it's like, you know, our technology picks up an anomaly or someone sees something, we say it's aliens. And I think the real thing is, it's not contact with events, but like, first contact is actually contact with knowledge of the phenomenon or the explanation. And so this is very subtle and very abstract, but when does it become something that we actually understand what it is that we're talking about? That's first contact. It's not-

• 2:53:08Lex Fridman?

  Would you make the myth? Would you give credit to the myth, the mythology as first contact?

• 2:53:14Sara Walker?

  I think, yes. I think it's the rudimentary that we have some understanding that there's a phenomenon that we have to understand and regularize. So I think-

• 2:53:22Lex Fridman?

  Right, to understand that there is weather.

• 2:53:24Sara Walker?

  Yes.

• 2:53:24Lex Fridman?

  You have to construct mythology around that weather.

• 2:53:26Sara Walker?

  Yes.

• 2:53:27Lex Fridman?

  It's something that's controllable.

• 2:53:29Sara Walker?

  Right.

• 2:53:30Lex Fridman?

  Yeah, like this is-

• 2:53:30Sara Walker?

  I see mythology, basically, as like baby knowledge.

• 2:53:34Lee Cronin?

  It could be that, you know, although there's lots of, there's lots of alien sites or so-called alien sightings, right? So there is a number of things you can do. You could just dismiss them and say they're not true. They're kind of made up. Or you say, well, there's some, there's something interesting here, right? We keep seeing a commonality, right? We see the same phenomena again, again, again. Also, this interesting thing about the human imagination, even if they are, let's not say made up, but misappropriated kind of other inputs, the fact that human consciousness is capable of imagining in contact with aliens, does that not tell us about something about where we are and our position in our culture and our technology?

• 2:54:12Sara Walker?

  It tells us about where and time we are.

• 2:54:14Lee Cronin?

  Could it be that we're making contact with, let's say that, so let's say, let's take the most miserable version, there are no aliens in the universe, life is only on Earth. That then, the interpretation of that is we're desperate to kind of understand why we're the only life in the universe, right? The other one is, the other most extreme is that aliens are visiting all the time and we just, you know, we're just not able to capture them coherently. Or there's a big conspiracy and, you know, there's the Area 51 and there are lizards everywhere and there's that. Or I'm, I'm kind of in favor of the idea that maybe humanity is waking up to the idea that we aren't alone in the universe and we're just running the simulation and we're seeing some evidence. You know, we don't, we don't know what life is yet. We are, we do have

• 2:54:56Lee Cronin?

  some anomalies out there. We can't explain everything. And over time, you know, we will start to unpack that. One very plausible thing we might do, which might be boring for the average alien observer or believes that aliens are, as in intelligent aliens are visiting Earth, it could be that we might go to the outer solar system and find a new type of life that has completely new chemistry. Bring these cells back to Earth, where you could say in my hand, on Earth, here's RNA, DNA and proteins and look, cells self-replicate from Titan, we got this new set of molecules, new set of cells, and we feed it stuff and it grows.

• 2:55:40Lee Cronin?

  That for me, if we were able to do that, which would be like the most, that would be my UFO sighting.

• 2:55:48Lex Fridman?

  That's a good test. So you feed it and it grows.

• 2:55:51Lee Cronin?

  Yeah.

• 2:55:53Lex Fridman?

  We've made, so not until you know how to feed the thing.

• 2:55:58Lex Fridman?

  And it grows somehow.

• 2:56:01Lee Cronin?

  We can make a comic book, you know, the tiger that came for tea, the alien that came for tea.

• 2:56:06Lex Fridman?

  What would, what would you say is, is between the two of you is the biggest disagreement about aliens, alien life out there? Is it from, from the basic framework of thinking about what is life to maybe what aliens look like, to alien civilizations, to UFO sightings? What would you think?

• 2:56:26Lee Cronin?

  So I would say the biggest one is that um, the emergence of life does not have to be, that can't just happen once on a planet, that it could be two or more life forms present on a planet at once. And I think Sarah doesn't agree with that.

• 2:56:42Sara Walker?

  I think that's like logically inconsistent.

• 2:56:46Lee Cronin?

  That's really polite. You're saying it's nonsense, but, because you think that, yeah.

• 2:56:50Lex Fridman?

  How likely is that? So the idea that, what is, what does it look like? Let's imagine two alien civilizations coexisting on a planet. What's that look like exactly?

• 2:57:00Lee Cronin?

  So I would say, um, I think I've got to get around your argument. Yeah, let's say, let's say that on this planet, there's just like, there's lots of available chemistry. And one life form gets, emerges based on carbon and interacts. And there's like, there's an ecosystem based on carbon. And there's an orthogonal, um, and so it's planetary phenomena, which is what you, I think, right? But there's also one that carries on silicon. And, and because there's enough energy and there's enough stuff, that these life forms might not actually necessarily compete, um, evolutionarily.

• 2:57:36Sara Walker?

  Yeah, but they would have to not interact at all because they're going to be co-constructing each other's causal chains.

• 2:57:41Lee Cronin?

  I think that's where you just got me, yeah.

• 2:57:42Lex Fridman?

  So there's no, so there's no overlap? In terms of their causal chains, they're very limited.

• 2:57:49Lee Cronin?

  Yeah, so I think the only way I can get away with that is to say, right, life could emerge on a planet underneath. And, okay.

• 2:57:55Sara Walker?

  Lizard people under the crust of the earth.

• 2:57:57Lee Cronin?

  I think, I think, I think, let's go, I, I think, but look, as you can see, we disagree. So, and I think Sarah actually has convinced me because of that, that life is a planetary phenomenon. The emergence of life is a planetary phenomena. And, and actually, because of the way evolution and selection works, then nothing occurs in isolation. The causal chains interact, so there is a common, there's a consensus model for life on the earth.

• 2:58:21Lex Fridman?

  But you don't think you can place aliens from elsewhere onto the, can't you just place multiple alien civilizations on one planet?

• 2:58:31Sara Walker?

  Right, but I think, so you can take two origin of life events that were independent and co-mingle them. But I don't think, when you're talking about, when you, when you look at the interaction of that structure, it's, it's like the same idea. It's like an experiment being an example of life, right? That's a really abstract and subtle concept. And I guess what I'm saying is, life is information propagating through matter. So, once you start having things interacting, they, in some sense, co-mingle and they become part of the same chain. So.

• 2:59:06Lex Fridman?

  The co-mingling starts quickly.

• 2:59:08Sara Walker?

  Yeah.

• 2:59:08Lex Fridman?

  Proceeds, we proceed to co-mingle quickly.

• 2:59:11Sara Walker?

  Right, right. So you, you could say, so the question is then, the more interesting question is, are there two distinct origins events? And I still think that there's reasons that on a single planet, you would have one origins event because of the time scales of cycling, of geochemistry on a planet. And also the fact that I don't think that the origin of life happens in a pool and like radiates outward through evolutionary processes. I think it's a multi-scale phenomenon. It happens at the level of individual molecules interacting, collections of molecules interacting, and entire planetary scale cycles. So, life as we know it. Has always been multi-scale and there's brilliant examples of individual mutations at the genome level changing global climate.

• 2:59:53Sara Walker?

  Right, so there's a tight coupling between things that happen at, you know, the largest scale, our planetary scale, and the smallest scale that life mediates.

• 3:00:03Lex Fridman?

  But it still might be difficult within something you would call as a single alien civilization, you know, different, they're species and stuff.

• 3:00:10Lee Cronin?

  But I think what

• 3:00:11Sara Walker?

  Yeah.

• 3:00:11Lex Fridman?

  And they might not be able to communicate.

• 3:00:13Sara Walker?

  But you're asking about life, not species, right?

• 3:00:15Lex Fridman?

  But what's the difference between one living civilization? This is almost like a category question.

• 3:00:23Sara Walker?

  Yeah.

• 3:00:24Lex Fridman?

  Versus species, because they can be very different.

• 3:00:28Sara Walker?

  Right.

• 3:00:28Lex Fridman?

  Like the way evolution, because there's like island, like literally islands, you can evolve different kinds of turtles and stuff.

• 3:00:34Sara Walker?

  Yeah.

• 3:00:34Lex Fridman?

  And they can

• 3:00:36Sara Walker?

  So I guess what I'm saying is

• 3:00:37Lex Fridman?

  Weird.

• 3:00:38Sara Walker?

  If you look at the structure of two interacting living things, populations, and you look in their past and they have independent origins for their causal chain, then you would say one was alien, you know, they have different independent origins events. But if you look at their future, by virtue of the fact they're interacting, their causal chains have become co-mingled so that then in the future, they, they are not independent.

• 3:01:04Lex Fridman?

  Right.

• 3:01:04Sara Walker?

  Right, so that's why you would even define them as alien. So the structure across time is two examples of life become one example of life because life is the entire structure across time.

• 3:01:15Lex Fridman?

  Right, but there could be a lot of variation within.

• 3:01:18Sara Walker?

  Yeah, so the question we're all interested in is how many independent origins of a complexifying causal chain are there in the universe?

• 3:01:27Lex Fridman?

  See, but the idea of origin is easy for you to define? Because like, when the two, when the species split in the evolutionary process and you get like

• 3:01:43Lex Fridman?

  A dolphin versus a human or Neanderthal versus Homo sapiens, isn't there?

• 3:01:49Lee Cronin?

  Let me make a distinction here quickly. So I think, sorry to interrupt. What we're saying, I mean, I mean, I mean, Sarah won that argument because she, I think she's right. That once the causal chains interact and going forward. So we're talking about a number of things. Let's go all the way back before origin of life, origin of life.

• 3:02:07Lex Fridman?

  On Earth.

• 3:02:08Lee Cronin?

  On Earth. Chemistry emerges. So there's all these, I would say there's probably mechanistically, the chemistry is desperately trying to find any way to get replicators. The ribosome kind of was really rubbish at the beginning and they just competed, competed, competed. And you got better and better. Ribosome, suddenly that was a technology. The ribosome is the technology that way, boom, allowed evolution to start. So what I was trying to, why I interrupted you is say that once evolution has started using that technology, then you can speciate. And I was trying to, and I think what Sarah said was convinced me of. Cause I was like, no, we're going to have lots of different chemistry, shadow biosphere on Earth.

• 3:02:47Lee Cronin?

  And she's like, no, no, no, you have to have this, you have to get to this minimum evolutionary machine. And then when that occurs, speciation occurs, exactly what you say, dolphins, humans, everything on Earth. But when you're looking at aliens or alien life, there's not going to be two different types of chemistry because they compete, they compete and interact and cooperate because the causal chains overlap. One might kill the other, one might combine with the other, and then you go on. And then you have this kind of this average, and sure, there might be respeciation. It might be you have two types of emerging chemistry. It almost looks like the origin of life on Earth required two different pre-life forms,

• 3:03:29Lee Cronin?

  the peptide world and the RNA world, somehow they got together. And by combining, you got the ribosome and that was the minimum competent entity for evolution.

• 3:03:38Lex Fridman?

  And would all alien civilizations have an evolutionary process on a planet? So like, that's one of the almost, it's almost the definition of life. To create all those memories, you have to have something.

• 3:03:53Sara Walker?

  Things have to change in time.

• 3:03:54Lex Fridman?

  Yeah. And then, but there has to be selection.

• 3:03:58Lex Fridman?

  That's like an efficient, there's no other way to do it.

• 3:04:01Lee Cronin?

  No, well, never say never because soon as I say that someone says.

• 3:04:04Sara Walker?

  That's the part that depresses me, though, going back to like, I don't know, the earlier discussion on violence and things like, and I don't know where, somebody was tweeting about this recently, but like, you know, how much stuff had to die. Maybe it was you.

• 3:04:17Lex Fridman?

  Yeah.

• 3:04:17Sara Walker?

  Ah, yeah. So.

• 3:04:20Lex Fridman?

  So we were talking, we're talking about life.

• 3:04:22Sara Walker?

  Yeah.

• 3:04:22Lex Fridman?

  And I guess a lot of murder had to occur.

• 3:04:27Sara Walker?

  Right. So selection means things had to be weeded out, right? So.

• 3:04:31Lex Fridman?

  Well, we can celebrate that. Death makes way for.

• 3:04:34Sara Walker?

  Yeah, I mean, it is. And also, you know, one of the most interesting features of of major extinction events in the history of our planet is how much novelty emerged immediately after. Right? So and of course, you know, a lot of people make arguments, we wouldn't be here if the dinosaurs didn't go extinct. So in some ways, we can attribute our existence to all of that. But I guess I was just wondering, and sort of like, if I was going to build a universe myself, in the most optimistic way, would I retain that feature? But it does seem to be a universe.

• 3:05:04Lee Cronin?

  I think you have to. I mean, I think we're, I think we're probably being over anthropomorphizing. I remember watching the blue, I think it was the blue planet, David Attenborough was showing these seals and because of climate change, some seals were falling off a cliff and how tragic that was. I was like, I'm saying to my son, that's pretty cool. Look at, look at those ones down there. They've obviously got some kind of mutations, some, and they're not doing that daft thing. And so that, that, that poor gene will be weeded out. Of course, at the individual level, it looks tragic. And of course, as human beings, we have the ability to abstract and we empathize. We don't want to cause suffering on other human beings and we should retain that. But we shouldn't look back in time and say, you know, how many butterflies had to die?

• 3:05:47Lee Cronin?

  I remember making, how many, if you think about the caterpillar become the chrysalis and then the butterfly getting out. How many, if that suffering, we call it suffering, if that process of pruning had not occurred, we have no butterflies. So none of the butterfly beauty in the world without all that pruning. So pruning is required, but we shouldn't anthropomorphize and feel sorry for the biological entities.

• 3:06:12Lee Cronin?

  But because that's that seems to be a backwards way of looking at it. What we should do is project forward and maybe think about what values we have across our species and our ecosystem and our fellow human beings. You know, you know, now that we know that animals suffer at some level,

• 3:06:29Lee Cronin?

  think about humane farming. When we find that plants can in fact are conscious and can think and have pain, then we'll do humane gardening. Until that point, we won't do it, right?

• 3:06:40Lex Fridman?

  I like this.

• 3:06:42Lex Fridman?

  Famous chemist endorses the majestic nature of murder. That's the title.

• 3:06:49Lee Cronin?

  I didn't say that, but anyway.

• 3:06:51Lex Fridman?

  Well, I just insert.

• 3:06:52Sara Walker?

  I have a hard time with it, though. I think the way you put it is kind of.

• 3:06:56Lex Fridman?

  But it's the reality of it's the reality of it is beautiful. You know, there's an Instagram account called Nature is Metal. And I keep following and unfollowing it because I can't handle it for prolonged periods of time.

• 3:07:11Lee Cronin?

  We evolve together, you die alone.

• 3:07:13Sara Walker?

  Yeah.

• 3:07:14Lex Fridman?

  We evolve together, but you die alone.

• 3:07:16Sara Walker?

  So I.

• 3:07:17Lex Fridman?

  We live alone, too. It's a Gatsby thing. I don't know. We evolved together. Where's the together? The together is the murder.

• 3:07:24Lee Cronin?

  The population.

• 3:07:24Lex Fridman?

  And the sex.

• 3:07:25Sara Walker?

  I just.

• 3:07:25Lex Fridman?

  Sex and murder.

• 3:07:26Sara Walker?

  My romantic vision of it to try to make me happy, Sarah, instead of sad Sarah. I talk in third person when I think very abstractly, sorry.

• 3:07:35Sara Walker?

  Is, you know, like, like this whole, like, you know, the like, certain things can coexist. So the universe is trying to maximize existence, but there's some things that just aren't the most productive, productive trajectory together. But it doesn't mean that they don't exist on another timeline or another chain somewhere else. Like I like, and maybe you would call that like then some kind of multiverse or things. But what am I saying?

• 3:07:59Lee Cronin?

  I think you can't, I just, you can't go down a level.

• 3:08:01Sara Walker?

  I'm just making stuff up.

• 3:08:02Lee Cronin?

  No, you're not.

• 3:08:03Sara Walker?

  To myself feel better.

• 3:08:04Lee Cronin?

  I don't underst- is it logical? And we need.

• 3:08:07Sara Walker?

  No, I know, I know.

• 3:08:08Lex Fridman?

  Yeah, if you look at bacteria, if you look at virus, I mean, just, just the number of organisms that are constantly like looking at bacteria, they're just dying nonstop. It's like a slaughter.

• 3:08:17Sara Walker?

  Right.

• 3:08:18Lee Cronin?

  So.

• 3:08:18Sara Walker?

  Well, and this goes back to the conversation about God. I mean, like, there's the whole thing about like, why is the universe enabled suffering?

• 3:08:23Lee Cronin?

  Individuals don't exist, right? In the individual, so for this, I think if you think about life as an entity on earth, right? Let's just go back a second. I mean, I like to, I'll be ludicrous for a second. I don't exist. You don't exist, right? But the actions you do, the product of evolution exists, right? The objects you create exist quantitatively in the real world. If you then understand life on Earth, or alien life, or any life in the universe, as this integrated entity, where you need cells in your body to die, otherwise you'd just get really big and you wouldn't be able to walk around, right? So you do.

• 3:09:01Lex Fridman?

  Yeah.

• 3:09:03Lee Cronin?

  So I think.

• 3:09:06Sara Walker?

  It's the patterns that persist, not the physical things.

• 3:09:08Lee Cronin?

  And of course, we have, we place immense values on fellow human beings. And I'm a majestic professor, does like other individual human beings.

• 3:09:18Sara Walker?

  Now you're talking in third person, too.

• 3:09:19Lee Cronin?

  I know, it happens, right?

• 3:09:20Lex Fridman?

  So death, would you say, I mean, because you said evolution is a fundamental part of life. So death is a fundamental part of life?

• 3:09:28Lee Cronin?

  Yeah. Right now, it might not be in the future. We might hack some aspects of death and we'll evolve in different ways.

• 3:09:37Lex Fridman?

  But isn't there, I think Sarah mentioned like this life density.

• 3:09:43Lex Fridman?

  Can't that become a problem? Like too much bureaucracy, too much baggage builds up? Like you need to keep.

• 3:09:52Sara Walker?

  I think it's okay that we dissipate. Like, I don't think of like, like.

• 3:09:57Sara Walker?

  No, but I mean, like, we're so fixated on ourselves as individuals and agents. And we were talking about this last night, actually, over dinner, but like, you know, an individual persists for a certain amount of time. But what you want to do, like, if you're really concerned with immortality, is not to live indefinitely as an individual, but maximize your causal impact. So like, what are the traces of you that are left? And you're still a real, I always think of Einstein, like, for a period of time, he was a real physical thing. We identify as a human, and now we just see echoes of that human in all of the ways that we talk about his, you know, causal impact. Frankly, right, is another great example.

• 3:10:35Lee Cronin?

  How many Easter eggs could you leave in the future?

• 3:10:38Sara Walker?

  So I guess the question is, how much do you want to control the localization of a certain features? Of, say, a packet of propagating information we might call a person? And keep them localized to one individual physical structure? Or do you want to, you know, is there a time when that just becomes a dissipated feature? The society that it once existed in. And I'm OK with the dissipated future because I just think that makes more room for more creativity in the future.

• 3:11:07Lex Fridman?

  So you mentioned engineering life in the lab. Let me take you to computer science world. What about robots? So is it possible to engineer? See, because you're really talking about like engineering life at the chemistry level. But do you think it's possible to engineer a life at the humanoid level, at the dog level? Like, or is that, like, at which level can we instill the magic of life into inanimate stuff?

• 3:11:44Sara Walker?

  No, I think you could do it at every level. I just think that we're particularly interested in chemistry because it's the origin, life, transition that presumably, or at least is how I feel about it, is going to give you the most interesting or deepest insights into the physics. But presumably, everything that we do and build is an example of life. And the question is just how much do you want to take from things that we have now and put them into like examples of life and copy them into machines?

• 3:12:14Lex Fridman?

  I saw that there was this tweet again. I think you were at the Mars conference and you were hanging out with a humanoid robot.

• 3:12:20Sara Walker?

  Yes. That was a fun.

• 3:12:22Lex Fridman?

  Making lots of new friends at Mars 2020. Did you guys color match ahead of time with the robot? Or did that accidentally happen?

• 3:12:30Sara Walker?

  Accidentally, I went up and I wanted to say hi.

• 3:12:33Lex Fridman?

  Torpoise, would that be the correct name for the color?

• 3:12:36Sara Walker?

  I think so. We didn't color coordinate our outfits.

• 3:12:39Lex Fridman?

  Well, you didn't, maybe the robot did.

• 3:12:41Sara Walker?

  The robot probably did, much more stylish.

• 3:12:44Lex Fridman?

  So for people who are just listening, there's a picture of Sarah standing next to a humanoid robot. I guess you like them with a small head and perfect vision.

• 3:12:53Sara Walker?

  Actually, no, I just.

• 3:12:55Lex Fridman?

  Who I did their perfect, there's a lidar.

• 3:12:58Sara Walker?

  No, I mean, I think I was just deeply interested because.

• 3:13:01Lex Fridman?

  What was, sorry to interrupt. Was it manual control? Was it actually stabilizing itself?

• 3:13:06Sara Walker?

  Oh, no, it was walking around.

• 3:13:08Lex Fridman?

  Oh, nice.

• 3:13:08Sara Walker?

  Yeah.

• 3:13:09Lex Fridman?

  Nice.

• 3:13:10Sara Walker?

  It was pretty impressive. I mean, actually, there's some videos online of Jeff Bezos walking with one of those across the lawn nearby there.

• 3:13:17Lex Fridman?

  This is great.

• 3:13:18Sara Walker?

  Yeah.

• 3:13:20Sara Walker?

  So.

• 3:13:21Lee Cronin?

  I wasn't invited.

• 3:13:26Sara Walker?

  Yeah, but.

• 3:13:28Sara Walker?

  There you go. See?

• 3:13:31Lee Cronin?

  That's incredible, isn't it?

• 3:13:32Sara Walker?

  Yeah.

• 3:13:33Lee Cronin?

  So you look at the walking robot. Where did the idea for walking come from? It was invented by evolution, right? And us as human beings able to conceptualize and design and engineer the causal chain. So that robot is evidence of life. And so I think what's going to happen is there's the we want to find where the spark comes from mechanistically. How can you literally go from sand to cells? So that's the first transition, I think. You know, there are a number of problems we want to do. Make life in the lab. Great. Then we want to make life in the lab and want to suddenly start to make intelligent life or life that can solve, start to solve abstract problems. And then we want to make life that is conscious. Okay? In that order? I think it has to happen in that order.

• 3:14:17Lee Cronin?

  You know, this getting towards this artificial general intelligence. I think that artificial general intelligence can't exist in a vacuum. It has to have a causal chain all the way back to Luca, right?

• 3:14:27Sara Walker?

  Yeah.

• 3:14:28Lee Cronin?

  And so the question, I think, I really like the question is to say, what are, how is? How is our pursuit of more and more lifelike? I know you want to, you like your robots. You want to project into them. You want to interact with them. You, you, I think you would want, if you have a robot dog and the robot dog does everything expected of a normal dog and you can't tell the difference, you're not really going to ask the question anymore if it's a real dog or not. Or you've got a personality, you're interacting with it. And so I think what would be interesting would be to kind of understand the computational architecture, how that evolves. Cause you could then, you know, teleport the personality from one object to the other and say, right, does it act the same? And I think that as we go along, we're going to get better and better

• 3:15:13Lee Cronin?

  integrating our consciousness into machines. Well, let me ask you that question, just to linger on it.

• 3:15:21Lex Fridman?

  I would, I would call that a living conscious thing, potentially. Eyes as a human allegedly, but you're, would you, as a person trying to define life? If you passed the Turing test, are you a life form?

• 3:15:35Sara Walker?

  One of the reasons I walked up to the robot was because I wanted to meet the robot. Right, so I, it felt like I was, and I, I, I base a lot of my interaction with reality on emotion and feeling. But like, like, how do you feel about an interaction? And I always love your point about like, is it enough to have that shared experience with a robot? Right, so, so walking up to it, does it feel like you're interacting with a living thing? And it did, to an extent, but in some degrees, it feels like you're interacting with a baby living thing. So I think our relationship with technology, in particular, the robots we build is really interesting because basically they exist as objects in our future in some sense.

• 3:16:15Sara Walker?

  Like, we're a much older evolutionary lineage than robots are, but we're all part of the same causal chain. And presumably, you know, they're kind of in, in their infancy. So it's almost like you're looking at the future of life when you're looking at them, but it hasn't really become life in, in, in a full manifestation of whatever it is that they're gonna become. And, you know, the, the more, the example of the walking robot was super interesting, but they also had a dolphin that they put in the pool at the cocktail party at Mars, and it looked just like a real dolphin swimming in the pool. And, and you know, it's in this kind of uncanny valley because, and I was having this conversation

• 3:16:57Sara Walker?

  with a gentleman named Mutu, who was super perceptive, but he was basically saying like, it made him feel really uncomfortable.

• 3:17:04Lex Fridman?

  The dolphin?

• 3:17:06Sara Walker?

  Yeah, and I think a lot of people would have that response. And I guess my point about it is, it is kind of interesting because you're basically trying to make a thing that you think is non-living mimic a living thing. And so, so the thought experiment I would want to run in that case is imagine we replaced every living thing on Earth with a robot equivalent, like all the dolphins and things. And in some sense, then you're making, if you think that the robots aren't experiencing reality, for example, in the way that a biologically evolved thing would, you're basically making the philosophical zombie argument become real.

• 3:17:38Sara Walker?

  And and basically building reality into a simulation because you've made everything quote unquote fake in some sense. You've replaced everything with an emu a physical simulation of it.

• 3:17:49Lex Fridman?

  So as as opposed to being excited by the possibility of creating something new, you're terrified of being humans being replaced.

• 3:18:01Sara Walker?

  I was just trying to run like, what would be the absolute, you know, thought experiment? But I don't I don't think that scenario would actually play out. I guess what I I think is weird for why we feel this kind of uncanny valley interacting with something like the robot dolphin is we're looking at an object we know is kind of in the future in the sense of like if everything's ordered in time, but it's borrowing from a structure that we have common history with. And it's basically copying in a kind of superficial way things from one part of the causal chain to another. Yeah.

• 3:18:32Lex Fridman?

  Well, that's that's a video.

• 3:18:33Sara Walker?

  I never believed it was real. They look so real. And obviously, a technology was was developed for movies. So.

• 3:18:43Lee Cronin?

  But I think we're confusing our emotional response and understanding the causal chain of how we got there, right? Because a philosophical zombie argument thinks about objects just appearing, right? That you're facsimile in some way, whereas there is the cause of the chain of events that caused the dolphin to be built went for a human being.

• 3:19:01Lex Fridman?

  Yeah, would a philosophical zombies still have a high assembly index?

• 3:19:04Lee Cronin?

  Yeah. Because it came it can't be philosophical zombies can't like like Boltzmann brains just can't appear out of nowhere.

• 3:19:12Sara Walker?

  Well, I guess my question would be in that that scenario where you built all the robots and replaced everything on earth with robots with the with the biosphere be as creative under that scenario or not? And so are there are there quantitative differences you would notice over time?

• 3:19:24Lex Fridman?

  And it's not obvious either way, right?

• 3:19:26Sara Walker?

  It's not obvious right now because we don't really we don't understand. We haven't built into machines how we work.

• 3:19:32Lee Cronin?

  So that's, I think, the there are one of the big missing things that I think that we're both looking for, right?

• 3:19:38Sara Walker?

  This is a robot. It's a cute robot.

• 3:19:39Lee Cronin?

  But the but the point there is that the biosphere won't be as creative if you did it right now.

• 3:19:44Sara Walker?

  No, of course. I think that's why people don't like it.

• 3:19:46Lee Cronin?

  But in the but in the future. We will be able to solve the problem of origin of life, intelligence and consciousness, because they exist in physical substrates. We just don't understand enough about the material substrate and the causal chain. But I'm very confident we will get to an AGI. But it won't be what people think. It won't be, solution won't be a, we'll get fooled a lot. And so GPT-3 is getting better at fooling us and GPT-153 might really fool us, but it won't have the magic we're looking for. It won't be a creative, but it will help us understand the differences between what we-

• 3:20:27Lex Fridman?

  Really though? Because isn't that what love is? Being fooled? Like, why, why are you not giving much value to the emotional connection with objects, with, with robots, with humans?

• 3:20:40Lee Cronin?

  Emotion is a thing which happens when you're, when you're, the, the, your expectation function is dashed and something else happens. Right? I mean, that's what emotion is.

• 3:20:52Sara Walker?

  Is that what love is too?

• 3:20:53Lee Cronin?

  Yeah.

• 3:20:54Lex Fridman?

  You were expecting one thing and something else happened.

• 3:20:57Lee Cronin?

  Yeah.

• 3:20:58Lex Fridman?

  I don't know.

• 3:20:59Sara Walker?

  I don't think that's true either.

• 3:21:00Lee Cronin?

  Well, what is it then? I think, no, emotion, look, I'm sorry, emotion is that, but, but-

• 3:21:04Sara Walker?

  No, I think love is just fulfilling your purpose.

• 3:21:07Lee Cronin?

  No, but I'll, I mean, look, like, look-

• 3:21:09Sara Walker?

  Like, whatever that means, that's often what we're kind of-

• 3:21:11Lee Cronin?

  So, yeah, okay.

• 3:21:11Sara Walker?

  But when are you happiest? It's like when you're-

• 3:21:13Lee Cronin?

  All right, all right, all right. Let me go back. If you want to, if you want me to-

• 3:21:15Sara Walker?

  Follow your bliss.

• 3:21:16Lee Cronin?

  Let me define love quickly.

• 3:21:17Sara Walker?

  Okay, go for it.

• 3:21:18Lee Cronin?

  In terms of assembly space, right?

• 3:21:20Sara Walker?

  Excellent.

• 3:21:22Lee Cronin?

  I didn't think I'd be doing this today.

• 3:21:24Sara Walker?

  I can't wait till Assembly Theory 101 is taught and the second lecture is Assembly Theory of Love.

• 3:21:28Lee Cronin?

  No, but look, well, but actually, but look, but-

• 3:21:32Lex Fridman?

  It's being surprised. The expectation is being broken.

• 3:21:35Lee Cronin?

  I'm just, I'm not-

• 3:21:35Sara Walker?

  No, go for it. I want to hear you.

• 3:21:37Lee Cronin?

  I'm not, I'm not an emotional being. But I would say, so, let's talk, so, we'll talk about emotion, but love is more complex. Love is a very complex set of emotions together, and logical stuff. But if you've got this thing, this person that's on this causal chain, that has this empathy for this other thing, love is being able to project ahead in your assembly space and work out what you're, the person you're in love with has a need for, and to do that for them without, selflessly-

• 3:22:05Lee Cronin?

  Right, because you can project ahead what they're going to need and they are there and maybe you can see someone is going to fall over and you catch them before they fall over. Or maybe you can anticipate that someone's going to be hungry and without helping you, you just help them.

• 3:22:17Lex Fridman?

  That just sounds like empathy.

• 3:22:19Lee Cronin?

  But it's more complex than that, right? It's more complex. It's more about not just empathy, it's understanding, it's about kind of sharing that experience.

• 3:22:27Sara Walker?

  That's an expression of love, though. That's not what it's like to feel love. Like, feeling love is like, I think it's like when you're aligned with things that you feel like are your purpose or your reason for existing.

• 3:22:39Lex Fridman?

  So if you have those feelings towards a robot, why is that robot? I mean, because you said that AJ will build an AGI, but there'll be a fundamental difference in AGI.

• 3:22:51Sara Walker?

  I don't think we'll build it, it's going to emerge from our technology.

• 3:22:54Lee Cronin?

  I think you guys will all agree the same thing. I just said that GPT, that we do not correctly capture the causal chain that we have.

• 3:23:02Lex Fridman?

  Within GPT.

• 3:23:03Lee Cronin?

  Yeah, within.

• 3:23:04Lex Fridman?

  But don't you think it captures, because GPT three is fundamentally trained on a corpus of knowledge, you know, like the internet? Don't you think it gets better and better and better at capturing the memory of all the?

• 3:23:19Lee Cronin?

  It will be better at fooling you and at some point you won't care. But when it comes, I, my guess, this is a quick, this is what I was getting to right before we got, I got in the love trap.

• 3:23:30Lex Fridman?

  Love trap.

• 3:23:31Lee Cronin?

  It was like Lee Cronin in the love trap, you know?

• 3:23:36Lex Fridman?

  Sounds like a good band name.

• 3:23:37Lee Cronin?

  Makes it sad, okay, sad, Assembly Space is sad. No, is that, so sure, but I think there are other features that allow, that we pull on innovation that allow us to do more than what we just see in GPT three. So if you're being fooled there. So I think what I mean is human beings have this ability to be surprising and creative. Whereas is it Dali, this thing? Or if you take, GPT three is not going to create a new verb. Shakespeare created new verbs. You're like, wow. And that required Shakespeare to think outside of language in a different domain. So I think having that connections across multiple domains is what you need for AGI.

• 3:24:20Lex Fridman?

  Yeah, but I don't know if you need. I don't know if there's any limitations to GPT and not being able to be cost domain.

• 3:24:30Lee Cronin?

  The number one problem is it's instantiated in a resource limited substrate that we don't in silicon. It is the the architectures used for training, for learning is about fooling. It's not about understanding. And I think that there is some understanding that we have that is not yet symbolically representable.

• 3:24:52Lex Fridman?

  Language, learning language and using language seems to be fundamentally about fooling, not understanding. Why you use language exactly?

• 3:25:02Lee Cronin?

  I might disagree with that quite fundamentally, actually. But I don't, I'm not sure I understand how to make a coherent argument for that. But my feeling is that there is, there are, there is comprehension in reality, in our consciousness below language. And and we use those for language, for all sorts of expressions, and we don't yet understand that there's a gap. We will get there, but I'm saying, wouldn't it be interesting? It's a bit like saying, could I facsimile you or Sarah into a new human being? Right? And and let's just say I could copy all your atoms and the positions of all your atoms, the electrons into into this other person. They would be you. The answer is no.

• 3:25:46Lee Cronin?

  And it's quite easy to show using assembly theory, because actually the feature space that you have, that graph, the only way to copy you is to create you on that graph. So everything that's happened to you in your past, we have to have a faithful record for. If you want another copy of Lex, you have to do the exact thing. Want another copy of Sarah, want another copy of Lee? The exact past has to be replicated.

• 3:26:06Lex Fridman?

  Let me push back on that a little bit. That's maybe from an assembly theory perspective, but it, I don't think it's that difficult to recreate a version of me, like a clone, that would make everybody exactly equally as happy.

• 3:26:22Lex Fridman?

  Like they wouldn't care which one and like there's two of me and then they get to pick which one and they'll kill either one, they'll be fine, as long as they're forced to kill.

• 3:26:31Lee Cronin?

  They'll be fine, but here's what will happen is let's say we make artificial lex. And it was like, wow, it's so cool. It looks the same interact. Then there'll be this battle of like, right, we're going to tell the difference. We're going to, we're going to basically keep nudging lex and artificial lex until we get in novelty from one and we'll kill the other one. And I think thank God.

• 3:26:50Lex Fridman?

  But you don't, we're not, novelty is a fuzzy concept. That's the, this whole problem of novelty.

• 3:26:55Lee Cronin?

  So I will define novelty. It's not fuzzy. Novelty is the ability for you to create architectures that are, or create an architecture. So let's say you've got a corpus of architectures known, you can write down, you've got some distance measure. And then I create a new one and the distance measure is so far away from what you'd expected. There's, there's, there's no linear algebra going to get there. It's like, that is creativity. And we don't know how to do that yet on any level.

• 3:27:26Sara Walker?

  Well, I was also thinking about like your argument about free will, like you wouldn't be able to know it was, it doesn't work instantaneously. It's not like a micro level thing, but more a macro level thing over the scale of trajectories or longer term decisions. So if you think that the novelty manifests over those longer time scales, it might be the two lexes diverge quite a bit over certain time scales of their behavior.

• 3:27:50Lex Fridman?

  But nobody would notice the difference.

• 3:27:54Sara Walker?

  They might not.

• 3:27:55Lex Fridman?

  And the universe, the earth won't notice the difference. The universe won't notice.

• 3:28:00Sara Walker?

  Universe would notice the difference.

• 3:28:01Lex Fridman?

  No, the universe doesn't know about its novelty that's being generated. That's the whole point of novelty.

• 3:28:06Sara Walker?

  Yeah, but this is what selection is, right? It's like taking nearly equivalent ones and then deciding, like the universe selects, right? So whatever selection is, selects some things to persist in time.

• 3:28:17Lex Fridman?

  Yeah, it's going to select the artificial one, just because it likes that one better.

• 3:28:21Lee Cronin?

  Well, you're mixing up two arguments here. So look, let's go back a second.

• 3:28:24Sara Walker?

  What are you basing this argument on, Lex?

• 3:28:26Lex Fridman?

  I'm just saying that I kind of don't think, because Lee said that it's not possible, like if you, the, if you copy every single molecule in a person's body, that's not going to be the same person. That they won't have the same assembly index. It won't be the same person. And I just don't, I think copying, you can compress. Not only do I disagree with that, I just, I think you can even compress a person down to some, where you can fool the universe.

• 3:28:56Lee Cronin?

  I'm saying, let me restate it. It is not possible to copy somebody on, because you, unless you copy the causal history.

• 3:29:05Sara Walker?

  Also, you can't have two identical, I mean, actually, I really like the idea that everything in the universe is unique. So even if like, there were two Lexes.

• 3:29:12Lex Fridman?

  I know you like that idea because you're human and you think you're unique.

• 3:29:15Sara Walker?

  Yeah, exactly. But also, I can make a logical argument for it, that even if we could copy, you know, all of your molecules and all their positions, the other you would be there. And you have a different position in space. You're distinguishable.

• 3:29:27Lee Cronin?

  Yeah, the other thing.

• 3:29:28Lex Fridman?

  How unique are you, just by the position in space, really?

• 3:29:31Sara Walker?

  Sure, but then how much does that slight translation of Lex?

• 3:29:35Lee Cronin?

  Well, that's one I can add.

• 3:29:36Lex Fridman?

  That's not an interesting. I see, but, but no, wait a minute. Is part of the definition of something being interesting is how much it affects the future?

• 3:29:46Sara Walker?

  Yes.

• 3:29:47Lee Cronin?

  Yes. But let me come back.

• 3:29:49Sara Walker?

  Don't you agree?

• 3:29:49Lee Cronin?

  But let me come back.

• 3:29:50Sara Walker?

  Do you disagree?

• 3:29:50Lee Cronin?

  One point quickly that you were making.

• 3:29:52Lex Fridman?

  Sure, I think I probably agree, yes.

• 3:29:54Lee Cronin?

  If, there's two Lexes, right? There's a robot Lex that you just basically, it's a, it is a charade. It's a facsimile. It's just coded to emulate you.

• 3:30:06Sara Walker?

  Are you robot Lex?

• 3:30:07Lex Fridman?

  I wouldn't know, right?

• 3:30:09Lee Cronin?

  But let's get there. It's a very important point here, because he's ducking and diving between this. So, so if I facsimile'd you into a robot, then it would, your robot might be, would be a representation of you now, but fundamentally be boring because you go and have other ideas. If however you built an architecture, that itself is capable of generating novelty, you would diverge in your causal chain. And you'd both be equally interesting to interact with.

• 3:30:33Lex Fridman?

  Yeah.

• 3:30:33Lee Cronin?

  We don't know that mechanism. All I'm trying to say is we don't yet know that mechanism. We do not know the mechanism that generates novelty. And at the moment, in our AIs, we are emulating. We are not generating.

• 3:30:46Lex Fridman?

  You don't think we're sneaking up on that? Do you think it's a funny?

• 3:30:49Lee Cronin?

  There is no ghost in the machine.

• 3:30:52Lee Cronin?

  And I want there to be one. I want the same thing you want. Sorry, I was.

• 3:30:55Lex Fridman?

  I know you want that as a human because everything you just said makes you feel more special.

• 3:31:01Lee Cronin?

  I want to be so. No, no, no. Screw my specialness. I just want to be surprised. If I.

• 3:31:05Lex Fridman?

  You don't think a robot can surprise you?

• 3:31:07Lee Cronin?

  If I, if you can produce an algorithm, instantiate it in a robot, surprise me, I will, I will, I will, I will, I will have one of those robots. It would be brilliant, but they won't, it won't surprise me.

• 3:31:18Sara Walker?

  But why, why is it a problem to think that humans are special?

• 3:31:23Lex Fridman?

  Maybe it's not the special. You're right. It's the better than.

• 3:31:26Sara Walker?

  Yes.

• 3:31:27Lex Fridman?

  Because then you start to not recognize the magic in other life forms that you either have created or you have observed. Cause I just think there is magic in legged robots moving about and they are full of surprises.

• 3:31:42Sara Walker?

  Yeah.

• 3:31:42Lex Fridman?

  So this is.

• 3:31:43Sara Walker?

  And personality.

• 3:31:44Lex Fridman?

  Yeah. So I'm a little.

• 3:31:48Lee Cronin?

  I know why you like cellular automata, right? But the, the specialness in your robot comes from the roboticist that built it.

• 3:31:58Lex Fridman?

  Yeah.

• 3:31:58Sara Walker?

  It's part of the lineage.

• 3:32:00Lee Cronin?

  Yeah. And so that's fine. I'm happy with that.

• 3:32:02Sara Walker?

  That's what I felt like looking at the standing robot was I was looking at four billion years of evolution.

• 3:32:06Lee Cronin?

  Yeah.

• 3:32:06Lex Fridman?

  Right.

• 3:32:06Lee Cronin?

  If it wasn't. So I think I'm happy. I mean, I'm happy we're going to coexist. I'm just saying you're going to get more excitement. There's something missing in our understanding of intelligence. Intelligence isn't just training. The, the way the neural network is conceived right now is great and it's lovely and it'll be better and we will argue forever, but you want to know. Wouldn't it be great if I said, look, I know how to invent an architecture and I can give it a soul. And what I mean by a soul is some, I know for real that there is internal reference. As soon as I not fake internal reference. And if we could generate that mechanism for internal reference, that's why our goal direct.

• 3:32:43Sara Walker?

  That's why you have to.

• 3:32:44Lee Cronin?

  We can do that.

• 3:32:45Sara Walker?

  Test for goal directness.

• 3:32:46Lee Cronin?

  Get that goal directness. You would love that robot more than the one that's just made to look like it does. Because you'll have more fun with it because you better generate search other problems, get more novelty. Hell, you'll be able to fall in love with that robot for real, but not the one that's faking it.

• 3:33:03Sara Walker?

  What about fake it till you make it?

• 3:33:05Lex Fridman?

  Well, I think a lot of people fall in love with fake humans. It's nice to fall in love with something that's full of novelty, yes. You know, I could imagine all kinds of robots that I would want to have a close relationship with. And I don't mean like sexual, I mean like intimacy. But I just don't think that novelty generation is such a special.

• 3:33:35Lex Fridman?

  Okay, there's like mathematical novelty or something like that. And then there's just humans being surprised. And I think we're easily surprised.

• 3:33:41Lee Cronin?

  That's fine, but that's.

• 3:33:42Lex Fridman?

  But you don't think that's a good definition.

• 3:33:44Lee Cronin?

  No, that's good. I'm happy to be surprised.

• 3:33:48Lee Cronin?

  But not globally surprised because someone else. But I really want, I was, why I'm a scientist, I really want to be the first to be surprised about something and the first thing in the first in the universe to have created that novelty. And to know for sure that that novelty has never occurred anywhere else. That's a real buzz, right?

• 3:34:06Lex Fridman?

  Is there a way to really know that?

• 3:34:07Lee Cronin?

  You have to have a really big look up table.

• 3:34:10Lex Fridman?

  Right.

• 3:34:10Lee Cronin?

  Yeah, you're never going to be know for sure, right? That's, that's one of the hard things about being and scientists searching for this type of novelty. Maybe that's why mathematics, mathematicians love discovery, but actually they are creating. And then when they do create a new mathematical structure that they can then they, you can, you can write code to work out whether there's, whether that structure exists before that. That's almost why I would love to have been a mathematician from that regard, to invent new math. That really I know pretty much for sure to not exist, does not exist anywhere else in the universe because so contingent.

• 3:34:44Sara Walker?

  Right, but this gets into like, you said a few times, and I still really don't understand how you actually plan to do this. To build an experiment that detects how the universe is generating novelty or that time is the mechanism. So the, the problem that we all have, which I think is what Lex is pushing against is if I build the experiment. You don't know what you put into it. So you don't know what, like if you, unless you can quantify everything you put in, all of your agency, all the boundary conditions, you don't know if you somehow biased it in some way. So is the novelty actually intrinsic to that experiment or to that robot? Or is it something you gave it, but you didn't realize?

• 3:35:20Lee Cronin?

  It's gonna be, it's gonna asymptote towards that, right? You're never gonna know for sure, but you can start to take out, you know, you can use good Bayesian approaches and just keep updating and updating and updating until you point to one

• 3:35:32Sara Walker?

  So you wanna bound on how much novelty generation could be?

• 3:35:36Lee Cronin?

  Yeah.

• 3:35:36Sara Walker?

  Got it.

• 3:35:38Lex Fridman?

  So the ability to generate novelty is correlated with high assembly index? With assembly index?

• 3:35:43Lee Cronin?

  Yeah, and yeah.

• 3:35:46Sara Walker?

  Cause the space of possibilities is bigger.

• 3:35:50Lex Fridman?

  So, um, that's the key. This could be a good, uh, so a running joke of like, why Lex is single? This could be a good part four.

• 3:36:01Lex Fridman?

  Uh, so you, so what you're looking for in a robot partner is ability to generate novelty.

• 3:36:12Lex Fridman?

  And that's, I suppose you would say it's a good definition of intelligence, too.

• 3:36:19Lex Fridman?

  Boy, is novelty a, um,

• 3:36:23Lex Fridman?

  a fuzzy concept.

• 3:36:26Sara Walker?

  Is creativity better?

• 3:36:29Lex Fridman?

  Yeah, I mean, that's, that's all pretty fuzzy.

• 3:36:31Lee Cronin?

  It's, it's, it's kind of the same. Maybe that's why aliens haven't come yet is because we're not creating enough novelty. Like, there's some kind of a hierarchy of novelty in the universe.

• 3:36:40Sara Walker?

  Well, I think novelty is like, things surprise you, right? So it's a very passive thing, but I guess I would remember by saying creativity is, I think it's much more active. Like, you think there's like a mechanism of like the things that exist are generating the creativity. Novelty seems to be there's some spontaneous production. It has, it's completely decoupled from the things that exist.

• 3:36:58Lee Cronin?

  No, I, I understand. I, I think

• 3:36:59Lex Fridman?

  That's really, really good.

• 3:37:00Lee Cronin?

  Creativity is the mechanism and novelty is the observable.

• 3:37:05Sara Walker?

  Yeah.

• 3:37:06Lex Fridman?

  Novelty could just be surprised, your model of the world was broken and, and not necessarily in a positive way.

• 3:37:12Lee Cronin?

  That's surprise. So there's three things now. Let's go back. That's cool. Right. Let's go. You've got surprise, which is basically. I'm, I don't, I mean, I'm surprised all the time because I don't read very much. I'm pretty dumb. I was like, oh, wow, this is it. I often used to invent new scientific, you know, ideas and I was really surprised by that. And then when looking at literature properly and it's there, so surprise, that's to the extent that you don't have full information.

• 3:37:34Lee Cronin?

  Creativity, the act of pushing on that, um, kind of on the causal structure and novelty, which is measuring that degree, right? So I think that's pretty well defined in that regard. So you want your robot, I mean, and in the, and in the end, that's why actually the way the internet and the printing press share some, um, I actually think creativity has dropped a bit since the creator, since the internet, because everyone's just, just, you know, just regurgitating stuff. But of course now it's beginning to accelerate again because everyone is using this tool to be creative and boom, it's exploding. So I think that's what happens when you create these new technologies.

• 3:38:13Lex Fridman?

  That's really, that's really helpful. There's a difference between novelty and surprise. Okay. I was, I think I was thinking about surprise.

• 3:38:19Lee Cronin?

  If you give me a toy that surprises me for a bit, it'd be great. Robot surprises me, you know?

• 3:38:24Sara Walker?

  An experiment that surprises you?

• 3:38:25Lee Cronin?

  Yeah, I mean, that's why I love doing experiments because I'm, I can't.

• 3:38:28Lex Fridman?

  It's still exciting. Surprise is exciting.

• 3:38:30Lee Cronin?

  Yep.

• 3:38:32Lex Fridman?

  Even negative surprise, like some people love drama in relationships. Like, it's like, why the hell, why, why'd you do this? That, that can be exciting.

• 3:38:41Lee Cronin?

  I could imagine companies selling updates to their, their companion robots that just basically generate negative surprise, just to, to spice things up a bit.

• 3:38:48Lex Fridman?

  Yeah, it's the push and pull. That's, that's one of the components of love. As you said, love is a complicated thing. Oh, uh, beauty, I wanted to mention this because you also tweeted, I think this was Sarah, no, it might've been Lee, I don't remember, but it was a survey published in nature showing that scientists, uh, find.

• 3:39:05Sara Walker?

  That's me, yeah.

• 3:39:06Lex Fridman?

  Yeah. Um, anyway, there's a, there's a plot, this is published in nature of what scientists find beautiful in their work and it separates biologists and physicists. It'd be nice if he showed the full plot. And there's simplicity, elegance, hidden order, uh, inner logic of systems, symmetry, complexity, harmony and so on. Um, is there any interesting things that stand out to you?

• 3:39:32Sara Walker?

  I think the fact that biologists like complexity and pleasing colors.

• 3:39:38Lex Fridman?

  Oh, there's pleasing colors on there. Yeah.

• 3:39:39Sara Walker?

  Yeah, or shapes.

• 3:39:40Lex Fridman?

  Or shapes. Pleasing colors and then physicists obviously love simplicity above all else. Simplicity, elegance.

• 3:39:48Sara Walker?

  Yeah.

• 3:39:48Lex Fridman?

  They love symmetry and then biologists love complexity and, well, they just love a little bit less.

• 3:39:56Sara Walker?

  They love everything a little bit less, but complexity a little bit more.

• 3:39:59Lex Fridman?

  A little bit more. That's so interesting.

• 3:40:02Sara Walker?

  And pleasing colors or shapes.

• 3:40:04Lex Fridman?

  Do you think it's a useful, I forget what your tweet was, that this is missing some of the something.

• 3:40:08Sara Walker?

  No, I think it's because I think about how explanations become causal to our future. So I have this whole philosophy that the theories we build and the way we describe reality should be, have the largest breadth of possibilities for the future of what we can accomplish. So in some sense, it's not like Occam's razor is not for simplicity. It's for optimism or the kind of future you can build. And so I think, I think you have to think this way when you're thinking about life and alien life. Because ultimately, we're trying to build, I mean, science is just basically our narratives about reality. And now you're building a narrative that is what we are as physical systems.

• 3:40:53Sara Walker?

  It seems to me it needs to be as positive as possible because it's basically going to shape the future trajectory where we're going. And we don't use that as a heuristic in theory building because we think theories

• 3:41:04Sara Walker?

  are about predicting features of the world, not causing them. But if you look at the history of all of the development of human thought, it's cause of things that happen next. So it's not just about looking at the world and observing it. It's about actually that feedback loop that's missing and it's not in any of those categories.

• 3:41:25Lex Fridman?

  What do you think is the most beautiful idea in the physics of life, in the chemistry of life, in this, through all your exploration with the sun blue theory?

• 3:41:39Lex Fridman?

  What is the

• 3:41:42Lex Fridman?

  the thing that made you step back and say this is this this idea is beautiful or potentially beautiful?

• 3:41:50Sara Walker?

  For me, it's that the universe is a creative place. I guess I I want to think, and whether it's true or not, is that we are special in some way, and it's not like an arbitrary added on epiphenomena or ad hoc feature of the universe that we exist. But it's something deep and intrinsic to the structure of reality.

• 3:42:10Sara Walker?

  And to me, the most beautiful ideas that come out of that is that the the reason we exist is for the universe to generate more things and to think about itself and use that as a mechanism for creating more stuff.

• 3:42:26Sara Walker?

  That's for me.

• 3:42:27Lex Fridman?

  So like the the life that this, however common it is, is an intrinsic part is a fundamental part of this universe, at least that we live in.

• 3:42:38Sara Walker?

  I think so. I mean, it's always interesting to me because you know, like, we have theories of quantum mechanics and gravity, and they're supposed to be like our most fundamental theories right now. And they describe, you know, things like the interaction of massive bodies or the way that charges accelerate or all these kind of features. And and they're these really deep theories, and they tell us a lot about how reality works, but they're they're completely agnostic to our existence. And I just I can't help but think that like, whatever describes us has to be even deeper than that.

• 3:43:08Lex Fridman?

  And I think incorporating memory, I guess.

• 3:43:12Sara Walker?

  Yeah.

• 3:43:12Lex Fridman?

  Causality, whatever the term you want to use into the physics view of the world might be.

• 3:43:17Sara Walker?

  That's the easiest way to do it. It's the it's the cleanest. So here we go again with the physicist. I'm a physicist. The clean, I was gonna say the simplest, most elegant way of resolving all of the kind of ways that we have, we have these paradoxes associated with life when you it's not that life is not current physics is not incompatible with life, but it doesn't explain life. And then you you want to know where are the explanatory gaps? And this idea that we have an assembly that time is fundamental and and objects actually are extended in time and have physical extent in time is the cleanest way of resolving a lot of the explanatory gaps.

• 3:43:55Lee Cronin?

  So I I I've been I struggled with assembly theory for many years because I could see this gap.

• 3:44:03Lee Cronin?

  And I think when I first met Sarah and we realized we were kind of talking about the same problem, but we were we understood none of the language. It was quite hilarious, actually, because it's like, I have no idea what we're talking about, but I think it's sounds right. So for me, the most beautiful thing about assembly theory is I realized the assembly theory explains why the universe, why life is a universe developing a memory. But not only that, poetically, I could actually go and measure it. And I was like, holy shit, we were just, we physically measured this thing, this abstract thing, and we could measure it. And not only could we measure it, but we can then start to quantify the causal consequences.

• 3:44:47Lee Cronin?

  And because, I mean, you know, I think as a kind of inventing this together with Sarah and her team.

• 3:44:55Lee Cronin?

  I thought there was a quite a high chance that, you know, we're doing science, there's such a high probability we're wrong. You know, on this, and I remember kind of trying to go to hard physicists, mathematicians, complexity theorists, and everyone just kind of giving me such a hard time about it. And so, you know, this is kind of, this is, you've just done this, you've just done that, it's, you know, you've just recapitulated an old theory. And I and I was unable, I lacked the language to really explain, and I had to, it was a real struggle. So this realization that life, what life does, that physics cannot understand or chemistry

• 3:45:37Lee Cronin?

  is the universe develops a memory that's causally actionable. And then we can measure it, but it isn't just a one thing, there is this intrinsic property of all the objects in the universe, like, like I've said before, but, you know, me holding up this water bottle, it's just any other water bottle, but it is a sum total of all the water bottles that have existed, right? And will likely change the future of water bottles and for other objects. So it's that this kind of so for me, assembly theory explains the soul in stuff.

• 3:46:10Sara Walker?

  The monology.

• 3:46:11Lee Cronin?

  But it is as the monology is not like Sheldon's morphic resonance where we have this kind of woo wee thing permeating the universe. It is the interaction of objects of other objects and some objects have more instantaneous causal power that's life, living things. And some objects are the instantaneous output of that causal power, dead objects, but they are part of the lineage. And that for me is fascinating and really beautiful. And I, and I think that even if we're determined to be totally wrong, I think it will help us help hopefully understand what life is and go into tech life elsewhere and make life in the lab.

• 3:46:49Lex Fridman?

  How's that make you feel, by the way? Does it make you feel less special that you're so deeply integrated, interconnected to the lineage?

• 3:46:57Lee Cronin?

  I mean, I can on one level, I just wanted in my life as a scientist, I wanted to have an interesting idea just once or an original idea. I mean, it was like, you know, so I think that was cool that we had this idea and we were playing with it. And I think also that I kind of, I mean, it took me ages to realize that Sarah had also had the same kind of form, coming towards the same formulation, just from a completely different point because I, but no, it makes me feel special and it also makes me feel connected to the universe. It also makes me feel not just humble about, you know, being a living object in the universe, but the fact that it makes me really optimistic about what the universe is going to do in the future because we're not just isolated phenomena, we are connected.

• 3:47:41Lee Cronin?

  I will be able to have, you know, one of my small objectives in life is to change the future of the universe in some profound way, just by existing.

• 3:47:51Lex Fridman?

  Yeah, that's not ambitious at all.

• 3:47:58Sara Walker?

  I think it's also good because it makes me feel less lonely because I just realized I'm not like, I mean, I'm a unique assembly structure, but I have so much overlap with the other entities I interact with that we're not completely individual, right?

• 3:48:10Lex Fridman?

  And yet, your existence does have a huge amount of impact on the, how this whole thing unrolls, on the future of the.

• 3:48:20Sara Walker?

  As individuals, that's, yeah.

• 3:48:22Lee Cronin?

  But I was gonna say.

• 3:48:23Sara Walker?

  Local packets of agency.

• 3:48:24Lee Cronin?

  I think we all have a profound impact on the future, some or the others, right? All human beings, all life. And I mean, that's why I think it's a privilege in a way for, you know, to say, to assert some degree of ego and agency. You know, I'm gonna make a computer or make an origin life machine or we can do this thing. But actually, it's just like, you know, life's probably living, if there is a god or there's a soul in everything, it's probably laughing at us going, I fool these guys by giving them ego. So they strive for this stuff and look what it does for, you know, the assembly space of the universe.

• 3:48:56Sara Walker?

  And there's always a possibility that science can't answer all of it. So that part's challenging for me.

• 3:49:02Lex Fridman?

  There may be a limit to this thing.

• 3:49:06Lex Fridman?

  Let me ask you a bunch of ridiculous questions and I demand relatively short answers. Lee, what's the scariest thing you've ever done?

• 3:49:19Lex Fridman?

  Yeah. Or what's a scary thing that pops to mind?

• 3:49:24Lee Cronin?

  Giving lecture, giving, giving seminars in front of other scientists.

• 3:49:27Lex Fridman?

  That's, yeah, that is terrifying. I could, if I had more time, I would ask you about the most embarrassing, but we'll spare you. What about you, Sarah? Scariest thing?

• 3:49:39Sara Walker?

  Um.

• 3:49:40Lex Fridman?

  Up there, some of the scary things you've done.

• 3:49:43Sara Walker?

  Um, actually, the scariest for me was deciding I want to get divorced because it was like a totally radical, like, um.

• 3:49:50Lex Fridman?

  Life transformation.

• 3:49:51Sara Walker?

  Yeah, because we had been married for a really long time. And I think it was just so much like I realized like so much of my individual agency I didn't realize I had before and that was just really like scary like empowering scary but like terrifying like you were living in a kind of one way for your whole life and then you realize your life could be a different way and

• 3:50:11Lex Fridman?

  Yeah, there is a between humans. I mean, that's the the beautiful thing about love is the the connection you have, but it's also becomes a dependency and breaking that whether it's a mentor, with your parents, your

• 3:50:22Sara Walker?

  It's almost like waking up, like, like, just there's a different reality. Yeah, that was scary.

• 3:50:26Lex Fridman?

  Reinventing yourself. Okay, if you could, Lee, if you maybe I'll actually will alternate. Sarah, if you could be someone else for a day, someone alive today, you haven't met yet, haven't met yet, or maybe you could do one who you've met, who would it be?

• 3:50:42Sara Walker?

  Kim Kardashian. No joke. The woman's brilliant. I would just like to experience like I just, I think she's got such an interesting and very deep understanding of social reality.

• 3:50:55Lex Fridman?

  But you also said you have appreciation, a love for fashion.

• 3:50:59Sara Walker?

  I do, but that but that's actually the same like I just think it's really interesting because we live in a social reality, which is completely artificially constructed. And some people are really genius about moving through that. And I think she's particularly good at it.

• 3:51:10Lex Fridman?

  I wonder if she's good at understanding or if she's

• 3:51:12Sara Walker?

  I think it's very deeply intrinsic to her. So I don't know if she

• 3:51:15Lex Fridman?

  She's like surfing a wave.

• 3:51:16Sara Walker?

  How much cognitive awareness she has of it or how strategic it is. But I think it's deeply fascinating. So I guess that's the first one that comes to mind.

• 3:51:23Lex Fridman?

  What about you, Lee? If you could be somebody for a day, don't say Yosher Bach.

• 3:51:28Sara Walker?

  Don't say Kim Kardashian.

• 3:51:30Lex Fridman?

  Those two off the table.

• 3:51:31Sara Walker?

  Off the table.

• 3:51:32Lee Cronin?

  No, I was gonna say I would like to like to be a, does that have to be here today? I was gonna say I'd like to be the latest arm processor.

• 3:51:43Lex Fridman?

  Oh, it could be a

• 3:51:45Lee Cronin?

  I would like to be the latest arm processor. I'd like to understand what I would like to know what it feel like to basically

• 3:51:53Sara Walker?

  You like being objects.

• 3:51:54Lee Cronin?

  I like being, I've always obsessed with being objects ever since I was a kid.

• 3:51:57Lex Fridman?

  What's the best part of being an ARM processor for a day?

• 3:52:00Lee Cronin?

  I mean, I'd like to understand how I access my memory, what I anticipate is coming next in clock cycles.

• 3:52:04Lex Fridman?

  What about how it feels like?

• 3:52:06Lee Cronin?

  Yeah, I want to know how it feels like to be.

• 3:52:09Lex Fridman?

  To be useful.

• 3:52:10Lee Cronin?

  To be.

• 3:52:12Lee Cronin?

  Thanks for that.

• 3:52:16Lex Fridman?

  All right, if, Leaf, everyone on Earth disappeared and it was just you left, what would your days look like? What would you do? Nobody else left to impress? Nobody, no, probably can't really do any real science at scale. What would you do with your remaining days?

• 3:52:34Lee Cronin?

  Get every possible tool I could and put it in my workshop and just make stuff.

• 3:52:40Lex Fridman?

  As, so try to make stuff?

• 3:52:43Lee Cronin?

  Just try and make stuff. Make companions. I'm probably not making companions, probably, yeah.

• 3:52:47Lex Fridman?

  In the physical space?

• 3:52:48Lee Cronin?

  Yeah.

• 3:52:50Lex Fridman?

  What about you, Sarah? What would you, when you're just left alone on Earth?

• 3:52:54Sara Walker?

  Are there animals in this scenario?

• 3:52:56Lex Fridman?

  No living beings.

• 3:52:58Sara Walker?

  No plants?

• 3:53:00Lex Fridman?

  No plants.

• 3:53:02Sara Walker?

  Oh, interesting. I was gonna say I would just, I would try to walk the entire planet, at least all the landmass.

• 3:53:07Lex Fridman?

  Well, that's, that's true. So you probably don't know if there's stuff, you could be, you could be searching for plants or other humans.

• 3:53:15Sara Walker?

  And what would I eat?

• 3:53:19Lex Fridman?

  You just have daily, just allotment.

• 3:53:23Sara Walker?

  I would just walk all the time.

• 3:53:24Lex Fridman?

  Of Soylent.

• 3:53:25Sara Walker?

  I don't know why I.

• 3:53:26Lex Fridman?

  Just walk.

• 3:53:27Sara Walker?

  That's just came to mind. I would just walk. And I guess I would make a goal of covering all of the entire Earth, because what else are you gonna do with your time?

• 3:53:35Lex Fridman?

  What's an item on your bucket list, Sarah, that you haven't done yet, but you hope to do?

• 3:53:41Lex Fridman?

  Skydiving, travel to space.

• 3:53:47Sara Walker?

  I don't know. You know, it's funny with my bucket list. I only know it was on my bucket list once I check it off.

• 3:53:53Lex Fridman?

  Once you check it off. So your bucket list is like a fog. It's like a mystery.

• 3:53:57Sara Walker?

  Yeah.

• 3:53:57Lex Fridman?

  Almost by doing it.

• 3:53:59Sara Walker?

  Yeah, so it's very subconsciously driven.

• 3:54:01Lex Fridman?

  So it's in your subconscious in there.

• 3:54:03Sara Walker?

  I think so.

• 3:54:04Lex Fridman?

  You're bringing it to the surface.

• 3:54:05Sara Walker?

  I think most of the steering of our agency is in our subconscious anyway. So I just kind of go with the flow. But I guess, um, no, seriously.

• 3:54:12Lex Fridman?

  Yeah, no, I get it. Yeah, thanks.

• 3:54:14Sara Walker?

  I don't know. I guess I, but I would like to go in a submarine, like to the bottom of the ocean. I think that'd be really cool.

• 3:54:17Lex Fridman?

  To the bottom of the ocean. Are you captivated by the mystery of the ocean?

• 3:54:21Sara Walker?

  I am, yeah.

• 3:54:24Lex Fridman?

  Yeah. What about you, Lee? What item on your bucket list?

• 3:54:29Lee Cronin?

  I don't have a bucket list, but I've just made one. I would love to take a computer to the moon or Mars and make drugs off-world. Be the first chemist to make drugs off-world.

• 3:54:39Sara Walker?

  The first drug manufacturer in space?

• 3:54:41Lee Cronin?

  Yeah, why not?

• 3:54:42Lex Fridman?

  Do they have to be somehow, like, be able to habitate, like, be able to survive on that particular space? Or, like, what's the connection between being on Mars and do?

• 3:54:53Lee Cronin?

  I just would like to be the, I'd like to take the ability to have command and control over chemicals programmatically off Earth to somewhere else in the universe.

• 3:55:03Lex Fridman?

  That just seems like you like difficulty engineering problems.

• 3:55:07Lee Cronin?

  Before I die, if I can do that, that's great.

• 3:55:09Lex Fridman?

  Would you travel to space, be free?

• 3:55:10Lee Cronin?

  Yeah. Yeah, that's what I'm saying. I'd love to go into space, but not just to be a tourist. I want to take scientific experiment in space and do a thing in space that's never been done before.

• 3:55:20Lex Fridman?

  That's a real possibility.

• 3:55:21Lee Cronin?

  Yeah, yeah. So that's why there's no point in listing things I can't do. Yeah.

• 3:55:27Lex Fridman?

  All right. What small act of kindness were you once shown that you will never forget?

• 3:55:35Lex Fridman?

  Small act of kindness, not big. Somebody was just kind to you. Somebody did something sweet.

• 3:55:42Lee Cronin?

  When I was a PhD student.

• 3:55:46Lee Cronin?

  Someone helped me out with a just I was basically I needed a computer. I needed some power, computation, power, and someone took pity on me and helped me. And gave me, I was really touched, they didn't have to. And they were actually quite, they were disabled scientists. They had other things to do rather than help some random PhD student. Gave me access, taught me a lot of stuff.

• 3:56:08Lex Fridman?

  Yeah, actually, when you're a grad student or when you're a student, when you're even a student, the younger it is, the better. The attention, the support, the love you get from an older person, a teacher, something like that is super powerful. Fascinating. And like from the perspective of the teacher, they might not realize the impact they have. But that little bit, those few words, a little bit of help can have a lot of impact. What about you, Sarah?

• 3:56:35Sara Walker?

  Um.

• 3:56:35Lex Fridman?

  Somebody give you a free Starbucks at some point?

• 3:56:38Sara Walker?

  I love free Starbucks. I like it when you're like in the line at Starbucks and somebody buys your coffee in front of you and then you buy the next one. I love those. But that's not my example.

• 3:56:47Lex Fridman?

  I love that too.

• 3:56:48Sara Walker?

  It makes me happy. And then my kids get all excited when we do it, when we go in. We're the first ones in line doing it. But um, I guess I can use a similar example about just being a student. So Paul Davies is a very well-known theoretical physicist and I, you know, he was generous enough with his time to take me on as a postdoc. But before I became his postdoc, he invited me to a workshop at Arizona State University in the Beyond Center and took a walk with me around campus just to talk about ideas after. And I think there were two things that were completely generous about that. One is Paul's philosophy is always interacting with young people. It's like you interact with a mind in the room.

• 3:57:34Sara Walker?

  It doesn't matter, you know, how well-known or whatever. It's like you evaluate the person for the person. So but he also gave me a book, The Eerie Silence, that he had written. And he wrote in it, this is how EE gets to ET, which was an anti-tumoric excess, which I worked on as a PhD student, was the origin of homochirality, all the way up to what the book was about, which was are we alone in the universe? And is there intelligent life out there? And it was just. So much about the questions I wanted to ask because it's like, it was just everything about like, just, it was, it was just really, really kind.

• 3:58:08Lex Fridman?

  Like that it's okay to ask these questions?

• 3:58:10Sara Walker?

  Yeah.

• 3:58:11Lex Fridman?

  And you can actually have strong enough to answer them.

• 3:58:13Sara Walker?

  A lot of my career is mostly his encouragement to ask deep questions. Like, he gave me the space to do it in ways that a lot of previous mentors had. I mean, I have, I've had a good experience with mentors, but it was like, go off the deep end, ask the hardest questions. And I think that's the best gift you can give somebody.

• 3:58:29Lex Fridman?

  What would you, because you're both fascinating minds and not, I would say, non-standard in the best possible way. Is there advice you can give to young folks, how to be non-standard, how to stand out, novelty, how to generate novelty?

• 3:58:46Lee Cronin?

  That's what I want on my tombstone. I have one.

• 3:58:49Lex Fridman?

  He, he generated novelty.

• 3:58:51Lee Cronin?

  No, no, how to.

• 3:58:52Lex Fridman?

  Oh, how to.

• 3:58:53Lee Cronin?

  How, how still.

• 3:58:56Lee Cronin?

  I just love doing science. And so when I was younger, I was just, just wanted to, I mean, I'm still not sure I'm a real scientist, right? So I want to try. So my advice for young people is just, if you just, if you love asking questions, then don't be afraid to ask the question, even if it pisses people off. Because if you piss people off, you're probably asking the right question. What I would say, though, is don't do what I did, which is just piss everyone off. Try and work out how to, you know, I think, if you're, if other people are challenged by your questions, you will get not only respect, but people will give you, create space for you because you're doing something really new.

• 3:59:40Lee Cronin?

  I really try to create space in my academic career, my, my team, really try and praise them and push them to do new things. So my advice is try to do new things, get feedback, and the universe will help you.

• 3:59:57Lex Fridman?

  Because the universe likes novelty. I think so. I think so, right? This one will keep them around. What about you, Sarah? You two like to ask the really out there.

• 4:00:08Sara Walker?

  Yeah, because I have a strong passion for them. So I think it goes back to the love. Like, if you're doing the thing you're supposed to be doing, you should really love it. So I always tell people that they should do the thing they're most passionate about. But I think a flip side of that is that's when you become in some might like, not to sound cheesy, but like your best version of yourself. So I guess like for me, as I become more successful in my career, I feel like I can be more myself as an individual. And so there's this, I've always been following the questions I'm most interested in, which very early on I was discouraged from doing by many people because they thought they were unanswerable questions. And I always just thought, well, if no one's even trying to answer them, of course, they're going to be unanswerable. And then that was kind of an odd viewpoint.

• 4:00:52Sara Walker?

  But the more I I found my way in that space, the more I also made a space for myself as a person because you're basically generating the niche that you want to exist in. And so I think I think that's that's part of it is not just to follow your passion, but also think about like, who do you want to be and create that?

• 4:01:14Lex Fridman?

  Yeah, who am I? Who do you want to be? I mean, yeah, play temporally with it.

• 4:01:19Sara Walker?

  Yeah, who am I now? Who do I want to be now? But who do I want to be in the future? They're not decoupled.

• 4:01:24Lex Fridman?

  Yeah, I always wonder if that's like, if I become something, am I finding myself or am I creating myself?

• 4:01:33Sara Walker?

  Yeah.

• 4:01:33Lex Fridman?

  And I think those are somehow the same kind of thing. I do feel often like that I was always meant to be this kind of thing.

• 4:01:40Sara Walker?

  Yeah.

• 4:01:41Lex Fridman?

  But is that created or discovered? I don't know, but basically go towards that direction. If you were abducted by aliens, Sarah?

• 4:01:51Sara Walker?

  Excellent. Waiting. They can come find me.

• 4:01:54Lex Fridman?

  They're on a spaceship there. And then they somehow figured out the language you speak and ask you, what are what are you? What is what? Explain yourself, not you, Sarah, but the species.

• 4:02:10Sara Walker?

  Oh.

• 4:02:11Lex Fridman?

  What's life on Earth? Like, we, we don't have time, we're busy grad students from another planet.

• 4:02:20Sara Walker?

  I see.

• 4:02:20Lex Fridman?

  What, what, what's interesting about human civilization? What's interesting about you? You specifically, too, they could be very kind of personal, kind of pushy.

• 4:02:32Lex Fridman?

  And, yeah. How, how would you?

• 4:02:35Sara Walker?

  I guess.

• 4:02:35Lex Fridman?

  We get to describe.

• 4:02:36Sara Walker?

  I, I, okay. I have one. Because, you know, like, at late, I, I, obviously, I self identify as a scientist and a physicist, but intrinsically, I feel more like an artist. But it's almost like you're an artist that you don't know what you're painting yet. And I guess I feel like that's humanity, like, in, in some sense. We're, we're, we're creating something, I think, is profound and, and potentially very beautiful, like, existence of the universe, but we're just so naive, like, not naive, we're just early. We're, we're early, we're, we're young, we don't know what we're doing yet.

• 4:03:07Lex Fridman?

  Yeah. What's with the nuclear weapons? This would be the question, too. Like, what are you guys?

• 4:03:11Sara Walker?

  What are we doing with them?

• 4:03:12Lex Fridman?

  Why, this creativity that you talk, it sounds very nice, but it's, you're.

• 4:03:16Sara Walker?

  We're making things that are.

• 4:03:18Lex Fridman?

  Like, very destructive and, like, the rockets, what, this seems very aggressive.

• 4:03:22Sara Walker?

  Yeah, I know. This is my, my blinders on.

• 4:03:27Sara Walker?

  I don't know. I, I mean, it goes back to the whole conversation about suffering. I have a hard time regularizing certain aspects of reality into what I want to envision. And that's obviously problematic, but, you know, nuclear power has also given us a lot of good things. So.

• 4:03:42Lex Fridman?

  So both, that's human nature, both, both human beings and the technology we create has the capacity for evil and the capacity for good.

• 4:03:50Sara Walker?

  Yeah, we can't all be good all the time. I mean, there's like this huge misnomer that you need to be liked by everyone universally. And obviously, that's like an ideal, but it's physically impossible. You, like, you can't get a group of people in a room and have everyone like each other all the time. So I think that kind of tension is actually really important, that we have different aesthetics, different goals. And, and sometimes.

• 4:04:16Sara Walker?

  Conflict comes out of that.

• 4:04:17Lex Fridman?

  Yeah. Speaking of which, do Yuli and Yoshua Bach ever say anything nice to each other? Or is it always conflict?

• 4:04:24Lee Cronin?

  We never have conflict. We argue, but I don't, I don't think like argue, arguments are bad.

• 4:04:28Lex Fridman?

  It's love.

• 4:04:29Lee Cronin?

  I mean, I, I think the problem I have, yeah, not a problem, I think.

• 4:04:32Lex Fridman?

  There we go. And he's not here to defend himself.

• 4:04:35Lee Cronin?

  No, I just, I don't necessarily understand the, the, I mean, he's just talking at such a high level.

• 4:04:41Lex Fridman?

  Yeah.

• 4:04:41Lee Cronin?

  You know, this, I'm, I'm a dimwit. So I'm like, I spend some, so I think a lot of our conflict is not conflict. We actually, we actually have a, I think, I mean, I can't speak for Yash, I have a deep appreciation for him. He's brilliant, but I, I think I'm kind of frustrated and I'm trying to, he thinks the universe is a computer and I want to turn the universe into a computer.

• 4:05:02Lex Fridman?

  Yeah, that's, that's a small disagreement. So what, what would you, how would you defend your life to an alien? When you're being abducted? Would you focus on the specifics of your life?

• 4:05:11Lee Cronin?

  I, no, no, no, I would be, I would try to be as random as possible and try and confuse them.

• 4:05:15Lex Fridman?

  Oh, good. Good.

• 4:05:21Sara Walker?

  Excellent.

• 4:05:22Lex Fridman?

  That might be the wiser choice.

• 4:05:24Sara Walker?

  The Easter eggs in reality?

• 4:05:25Lee Cronin?

  No, I mean, if aliens abducted me.

• 4:05:27Lex Fridman?

  Would you play dumb?

• 4:05:27Lee Cronin?

  No, I would try and be as random as, but I would try and do something that would surprise the hell out of them, which I thought, I mean, it probably might be risky, they might kill me, but I think that might be funny.

• 4:05:35Lex Fridman?

  That might, yeah, they might wanna study you for prolonged periods of time.

• 4:05:39Lee Cronin?

  My reasoning is if I wanted to stay alive, okay, so if the thing is if I wasn't going back to earth and the job was to stay alive, if I could be as surprising as possible, they'd keep me around like a pet, right?

• 4:05:50Lee Cronin?

  Petly on the alien's.

• 4:05:51Lex Fridman?

  So you'd be okay being, being a pet?

• 4:05:53Lee Cronin?

  Well, no, but I mean.

• 4:05:54Lex Fridman?

  The last, the last human that survives would just be a pet to the aliens.

• 4:05:58Lee Cronin?

  I, I don't know, but I mean, I think, um, that might be fun because then that might, might, I might get some feedback from their curiosity. But yeah.

• 4:06:05Lex Fridman?

  Let me ask you this question. It, given our conversation has a very different meaning, not a more profound meaning perhaps, but would you rather lose all of your old memories or never be able to make new ones?

• 4:06:21Lee Cronin?

  I would have to lose all my old memories.

• 4:06:26Lex Fridman?

  Again, it's the novelty.

• 4:06:29Lex Fridman?

  What about you, Sarah?

• 4:06:31Sara Walker?

  I'm the same because I don't think, like, it's about the future experience, right? And in some sense, like you were saying earlier, most of our lived experience is actually in our memories. So if you can't generate new memories, it's like you're not alive anymore.

• 4:06:44Lee Cronin?

  That's it, yeah.

• 4:06:46Lex Fridman?

  What comforts you on bad days? When you look at human civilization, when you look at your own life, what gives you hope? What makes you feel good about what we're doing, about life at the small scale of you as a human and at the big scale of us as a human civilization, maybe the big scale of the universe?

• 4:07:08Sara Walker?

  Children, my kids. But I also mean that in like a grand sense of like, not a grand, but like, like if future minds in some sense. So for me, like the most bleak movie ever, you know, people worry about apocalyptic things like AI existential risk and climate change was Children of Men. You know, the whole premise of the movie was there can be no children born on the entire planet. And the youngest person on the planet is like 18 years old or something. Like, can you imagine a world without children? It's just, it's harrowing. That's the scariest thing. So I think what gives me hope is always youth and the hope of children and the, you know, the possibilities of the future they see. And they grow up in a completely different reality than adults do.

• 4:07:53Sara Walker?

  And I think we have a hard time seeing what their reality actually looks like. But I think, I think most of the time it's super interesting.

• 4:08:02Lex Fridman?

  Yeah, they have dreams, they have imagination, they have this kind of excitement.

• 4:08:06Sara Walker?

  Yeah.

• 4:08:07Lex Fridman?

  So it's so cool, it's so fun to watch. And yeah, you feel like you're almost getting in the way.

• 4:08:14Sara Walker?

  Yeah.

• 4:08:14Lex Fridman?

  Of all that imagination. What about you, Lee? What gives you hope?

• 4:08:20Lee Cronin?

  So when I go back to my eight-year-old self, the thing that I dreamed of as my eight-year-old self was this world in which technology became programmable and there was internet and I'd get information. And I would expand my consciousness by just...

• 4:08:35Lee Cronin?

  Just, you know, getting access to everything that was going on. And this happened in my lifetime. I mean, really do have that. I mean, okay, there's some bad things, you know, there's TikTok. Everyone just, whatever, all the bad things about social media. But I think, um, I mean, I can't quite believe my luck being born now. So amazing.

• 4:08:57Lex Fridman?

  Be able to program reality in some way.

• 4:08:59Lee Cronin?

  Yeah. And the thing that I really find fascinating about human beings is that just how ingenious they are. I'm, you know, whether it's from my, my kids, my research group, my peers, other companies, just how ingenious everyone is. And, um, and I'm pretty sure humanity has a, or our causal chain in which humanity is a vital part in the future is going to have a lot of fun. And I'm just, yeah, it's just, it's just mind blowing just to watch. And, you know, so humans are ingenious and I, I hope to help them be more ingenious if I can.

• 4:09:35Lex Fridman?

  Well, what gives me hope, what makes me feel good on bad days is the existence of wild minds like yours, novelty generators, assembly structures that generate novelty and do so beautifully and then tweet about it. Uh, Sarah, this, I really, really enjoy talking to you. I enjoy following you. I'm a huge fan. Sarah Lee, I hope, I hope to talk to you many times in the future, maybe with Yoshua Bach. You're just incredible people. Thank you for everything you do. You're awesome. Thank you for talking today. Really, really appreciate it.

• 4:10:06Lee Cronin?

  Yeah, brilliant to be here.

• 4:10:08Lex Fridman?

  Thanks for listening to this conversation with Sarah Walker and Lee Cronin. To support this podcast, please check out our sponsors in the description. Now let me leave you with some words from Arthur C. Clarke. Two possibilities exist. Either we are alone in the universe or we are not. Both are equally terrifying.

• 4:10:31Lex Fridman?

  And let me, if I may, add to that by saying that both possibilities, at least to me, are both terrifying and exciting. And keeping these two feelings in my heart is a fun way to explore, to wander, to think, and to live, always a little bit on the edge of madness. Thank you for listening. I hope to see you next time.