Sara Walker: The Origin of Life on Earth and Alien Worlds | Lex Fridman Podcast #198

the following is a conversation with. sarah walker a nestor biologist and. theoretical physicist at arizona state. university and the santa fe institute. she's interested in the origin of life. how to find life on other worlds and in. general the more fundamental question of. what even life is. she seeks to discover the universal laws. that describe living systems on earth. and elsewhere using physics biology and. computation. quick mention of our sponsors athletic. greens netsuite blinkist and magic spoon.

check them out in the description to. support this podcast as a side note let. me say that my hope for this podcast is. to try and alternate between technical. and non-technical discussions to jump. from the big picture down to specific. detailed research and back to the big. picture and to do so with scientists and. non-scientists. long term i hope to alternate between. discussions of cutting-edge research in. ai physics biology. to topics of music sport and history and.

then back to ai. ai is home. i hope you come along with me for that. wild oscillating journey. some people message me saying to slow. down since they're falling behind on the. episodes of this podcast. to their disappointment i have to say. that i'll probably do more episodes not. less. but you really don't need to listen to. every episode just listen to the ones. that spark your curiosity think about it. like a party full of strangers you don't.

have to talk to everyone. just walk over to the ones who look. interesting and get to know them. and if you're lucky that one. conversation with a stranger might. change the direction of your life. and it's a short life so be picky with. the strangers you talk to at this. metaphorical party. this is the lex friedman podcast and. here is my conversation with sarah. walker. how did life originate on earth what are. the various hypotheses for how life. originated on earth yeah so.

i guess you're asking a historical. question which is always a good place to. start thinking about life um. so there's a lot of ideas about how life. started on earth um probably the most. popular is what's called the rna world. scenario um so this idea is probably the. one that you'll see most reported in the. news. and is based on the idea that there are. um. molecules in our bodies um that uh relay.

genetic information and we know those as. dna obviously but there's also sort of. an intermediary called rna ribonucleic. acid. that also plays the role of proteins. and. people came up with this idea in the 80s. that maybe that was the first genetic. material because it could play both. roles of being genetic and performing. catalysis and then somehow that idea got. reduced to this idea that there was a. molecule that emerged on early earth and. underwent darwinian evolution and that.

was the start of life. so there's a lot of assumptions. packed in there that we could unpack but. that's sort of the leading hypothesis. there's also other ideas about life. starting as metabolism and so that's. more connected to the geochemistry of. early earth. and it would be kind of more focused on. this idea that you get some kind of. catalytic cycle of molecules that can. reproduce themselves and form some kind. of metabolism and then life starts. basically as self-organization and then. you have to explain how evolution comes. later.

right so that's the difference between. sort of uh energy and genetic code so. like energy and information are those. are the two kind of yeah. yeah i think that's a good way of. putting that it's um. it's kind of funny because i think most. of the people that think about these. things are really disciplinary bias so. the people that tend to think about. genetics come from a biology background. and they're really evolution focused and. so they're worried about where does the. information come from and how does it. change over time but they're talking. about information in a really narrow way. where they're talking about a genetic. sequence and then most of people that.

think about. metabolism origins of life scenarios. tend to be people like physicists or. geochemists that are worried about what. are the energy sources and what you know. like what kinds of organization can you. get out of those energy sources okay so. which one is your favorite i don't like. either. okay all right can we talk about them. for a little bit longer though. uh so okay so there's uh early earth. what was that like was there just mostly. covered by oceans was there heat sources.

energy sources so if we. uh talk about the metabolism view of the. origin of life like where was the source. of energy probably the most popular view. for where the original life happened on. earth is hydrothermal vents because they. had sufficient energy. and so we don't really know a lot about. early earth. we have you know some ideas about when. oceans first formed and things like that. but the time of the original life is. kind of. um not well understood or pinned down. and the conditions on earth at that time.

are not well known. but a lot of people do think that there. was probably hydrothermal vents which. are really hot. chemically active regions say on the sea. floor in modern times which also would. have been present on early earth and. they would have provided energy and. organics. and basically all of the right. conditions for. the origins of life which is one of the. reasons that we look for these. hydrothermal systems when we're talking. about life elsewhere too. okay and for the genetic code. the idea is that the rna is the first.

like why would rna. be the first moment you can say it's. life. i guess the idea is it could both. have persistent information. and then it can also do some of the work. of like what creating a self-sustaining. organism. yeah that's the basic idea so the idea. is you have in an rna molecule you have. a sequence of characters say so you can. treat it like a string in a computer. and it can be copied so information can.

be propagated. which is important for. evolution because evolution happens by. having inheritance of information so for. example you know like my eyes are brown. because my mother's eyes were brown. so you need that copying of information. but then. you. also have the ability to perform. catalysis which means that that rna. molecule is not inert in that. environment but it actually interacts. with something that could potentially. mediate say a metabolism that could then.

fuel. the actual reproduction of that molecule. so. in some ways. people think that rna gives you. you know. the most bang for your buck in a single. molecule and therefore. you know it gives you all the features. that you might think are life um. and so that this is sort of where this. rna world conjecture came from is. because of those two properties. isn't it amazing that rna came to be. in general isn't it yes that is amazing.

okay so we're not talking down about rna. no no i love rna it's one of my favorite. molecules i think it's beautiful it's. just not step one. yeah i think i think the issue it's not. even the rna world is a problem and. actually if you really um dig into it. the rna world is not one hypothesis it. is a set of hypothesis. hypotheses sorry and they range from. a. molecule of rna spontaneously emerged on. the early earth and started evolving. which is kind of like the hardest rna.

world scenario which is the one i cited. and i get a little um. uh animated about because it seems so. blatantly wrong to me but that's a. separate story and then the other one is. actually something i agree with which is. that. you can say there was an rna world. because rna was the first genetic. material for life on earth so an rna. world could just be. the earliest organisms that had. genetics in a modern sense didn't have. dna evolved yet they had rna.

right and so that's sort of a softer rna. world scenario in the sense that it. doesn't mean it was the first thing that. happened. but it was a thing that definitely. was part of the lineage of events that. led to us. so if life was a. like a best of album it would be on the. maybe one of the songs on there yes one. of the early songs okay it's on the. greatest hits greatest hits that's the. word i was looking for okay did life do. you think originate once. twice three times on earth multiple.

times what do you think i think that's a. really difficult question um and an. important question it's a super. important question no that no it's a. really important question um and so. there there's some so there's. there's a lot of questions in that. question um so one of the first ones. that i think needs to be addressed is is. the original life a continuous process. on our planet so. we think about the original life is. something that happened on earth um say. almost four billion years ago because we. have evidence of life emerging very.

early on our planet. um. and then an original life event quote. unquote a singular event whatever that. was happened and then all life on earth. that we know. is a descendant of that particular event. in our universe right and so. um but. uh we don't have um. any idea one way or the other if the. original life is happening repeatedly. and maybe it's just not taking off. because life is already established. that's a argument that people will make. or.

maybe there are alternative forms of. life on earth that we don't even. recognize. um so this is the idea of a shadow. biosphere that there actually might just. be completely other life on earth but. it's so alien that we don't even know. what it is. i'm gonna have to talk to you about the. shadow biosphere. in a second but first let me ask for the. other alternative which is panspermia. right so that's the idea the hypothesis. that life exists elsewhere in the. universe and got to us through like an. asteroid. or a planetoid or some.

uh according to wikipedia space dust. whatever the heck that is. uh it sounds fun but basically rode. along. yeah whatever. kind of rock and got to us. do you think that's at all a possibility. sure so i think the reason that most. original life scientists are interested. in the origin of life on earth and say. not the original life. um. you know on mars and then panspermia you. know the exchange of life between. planets being the explanation is once.

you start removing the original life. from earth you know even less about it. than you do if you study it on earth. although i think there are ways of. reformulating the problem this is why i. said earlier like oh you mean the. historical original life problem you. don't mean the problem of how does life. arise in the universe and what the. universal principles are because there's. this historic problem how did it happen. on early earth and there's a more. tractable general problem of how does it. happen. and how does it happen is something we. can actually ask in the lab how does it. how did it how did it happen on early.

earth is. a much more detailed and nuanced. question and requires detailed knowledge. of what was happening on early earth. that we don't have. and i'm personally more interested in. general mechanisms so to me it doesn't. matter if it happened on earth or it. happened on mars. it just matters that it happened we have. evidence that happened. the question is did it happen more than. once in our universe and so the reason i. don't find panspermia as a particularly. i think it's a fascinating um hypothesis. i definitely think it's possible um and.

um. and i in particular i think it's. possible once you get to the stage of a. life where you have technology because. then you you obviously can spread out. into the cosmos um but it's also. possible for microbes because we know. that um certain microorganisms can. survive the journey in space and we you. know they can live in a rock and go. between mars and earth like people have. done experiments to try to prove that. could work um so in that scenario it's. super cool because then you get. planetary exchange but say we go find we. go look for life on mars and it ends up.

being exactly the same life we have on. earth biochemically speaking then we. haven't really discovered something new. about the universe what kind of aliens. are possible were there other original. life events if we find if all the life. we ever find is the same original life. event in the universe it doesn't help me. solve my problem but it's possible that. that would be a sign that you could. separate the environment from the. basic ingredients yes so that's true you. can have like a life gun. that you shoot throughout the universe.

and then uh. like once you shoot it it's like the. simpsons with a makeup gun that was a. great episode uh when you shoot this. life gun. it'll he'll find the earth's it'll like. get sticky it'll stick to the earth's. and that kind of reduces the barrier of. uh. like the time it takes the the luck it. takes to actually from nothing from the. basic chemistry from the basic physics. the universe for the life to spring up. yeah i think this is actually super.

important to just think about like does. life. getting seated on a planet have to be. geochemically compatible with that. planet so you're suggesting like we. could just shoot guns in space and like. life could go to mars and then it would. just live there and be happy there um. but that's actually an open question so. one of the things i was going to say in. response to your question about. whether the original life happened once. or multiple times is for me personally. right now in my thinking although this. changes on a weekly basis but um is that. i think of life more as a planetary.

phenomena so i think the original life. because um because life is so. um intimately tied to planetary cycles. and planetary processes and this goes. all the way back through the history of. our planet that the original life itself. grew out of geochemistry and became. coupled and controlled geochemistry and. and when we start to talk about life. existing on the planet is when we have. evidence of life. actually influencing properties of the. planet um and so. so if life is a planetary property um. then going to mars is not a trivial.

thing because you basically have to make. ours. mars more earth-like um and so in some. sense um like when i think about sort of. long-term vision of humans in space for. example. really what you're talking about when. you're saying let's send our. civilization to mars is you're not. saying let's send our civilization to. mars you're saying let's reproduce our. planet on mars like the information from. our planet actually has to go to mars. and make mars more earth-like which. means that you're now having a. reproduction process like a cell. reproduces itself to propagate.

information in the future. planets have to figure out how to. reproduce their conditions including. geochemical conditions on other planets. in order to actually reproduce life in. the universe which is kind of a little. bit radical but i think. for long-term sustainability of life on. a planet that's absolutely essential. okay so. if we were to think about life as a. planetary phenomenon. and so life on mars would be best if. it's way different than life on earth. we have to ask the very basic question. of.

what. is life. i actually don't think that's the right. question to ask. it took me a long time to get there. right so cross it out yeah you cross it. off your list it's wrong. no question um no no no i mean i think. it has an answer but i think the part of. the problem is um you know most of the. places in science where we get really. stuck is because we don't know what. questions to ask um and so you can't. answer a question if you're asking the. wrong question um and i think uh the way. i think about it is obviously i'm.

interested in what life is so i'm being. a little cheeky when i say that's the. wrong question to ask that's exactly. like the question that's like the core. of my existence but. um. but i think the way of framing that is. what is it about our universe that. allows features that we associate life. to be there um and so really what i. guess when i'm asking that question what. i'm after is an explanatory framework. for what life is right and so most. people they try to go in and define life. and they say well life is uh say a.

self-reproducing chemical system capable. of darwinian evolution that's a very. popular definition for life um or life. is something that metabolizes and eats. that is not how i think about life what. i think about life is there are. principles and laws that govern our. universe. that we don't understand yet. that have something to do with. how information interacts with the. physical world i don't know exactly what. i mean even when i say that um because. we don't know these rules um but it's a. little bit like um i like to use.

analogies you'll give me time to be like. a little long-winded for a second even. in as i um but um but sort of like if. you look at the history of physics for. example this is like so we are in the. period of the development of. thought on our planet where we don't. understand what we are yet right um. there was a period of thought in the. history of our planet where we didn't. understand what gravity was. um and we didn't understand for example. that planets in the heavens. you know were actually planets or that. they operated by the same laws that we.

did. um and so there has been this sort of. progression of getting a deeper. understanding of explaining basic. phenomena like i'm not gonna drop the. cup i'll drop the water bottle there you. go okay that fell right but why did that. fall um. this is why i'm a theorist not an. experiment. i could have gone wrong in so many ways. i know i could have especially if i did. the confidence smash anyway. um so um so if you think you take this. view that there's sort of some missing. principles i associate them uh to.

information and what it what the sort of. feeling there is there's some missing. explanatory framework for how our. universe works and if we understood that. physics it would explain what we are um. it might also explain a lot of other. features we don't associate to life um. and so it's a little like um people. accept the fact that gravity is a. universal phenomena but when we want to. study gravity we study things like large. scale. you know galactic structures or black.

holes or planets. if we want to understand information and. how it operates in the physical world we. study intelligent systems or living. systems because they are the. manifestation of that physics. and the fact that we can't see that. clearly yet or we don't have that. explanatory framework i think it's just. because we haven't been thinking about. the problem deeply enough but i feel. like if you're explaining something. you're deriving it from some more. fundamental property and of course. um i have to say i'm wearing my my. physicist hat so i have a huge bias of.

liking. simple elegant explanations of the. universe that. um. you know really are compelling but i. think one of the things that i've sort. of. maybe in some ways rejected my training. as a physicist is that most of the. elegant explanations that we have so far. don't include us in the universe and i. can't help but think there's something. really special about what we are and. there have to be some deep principles at. play there. um. and so so that's sort of my perspective. on it now when you ask me what life is i. have some ideas of what i think it is.

but i think that we haven't. gotten there yet because we haven't been. able to see that structure and it's and. just go back to the gravity example it's. a little like you know in ancient times. they didn't know i was talking about. stars and heavens and things they didn't. know those were um you know governed by. the same principles as that starting to. experiment here's where i was going with. it once you realize like newton did that. you know heavenly emotions and earthly. emotions are governed by the same. principles and you unify terrestrial and. celestial motion you get these more. powerful ideas.

um and i i think where life is is. somehow unifying these abstract ideas of. computation and information. with the physical world with matter and. realizing that there's some explanatory. framework that's not physics and it's. not computation but it's something. that's deeper. so. answering the question of what is life. requires. deeply understanding something about the. universe as information processing. universe is computation. something about.

like would uh once you come up with an. answer to what is life well the words. information and computation be in the. paragraph no i don't think so oh damn it. okay i know it doesn't help does it i. know i i hate actually i hate this about. what i do because it's so hard to. communicate right with words like when. you have words that are. um ideas that have historically. described one thing and you're trying to. describe something people haven't seen. yet right and the words just don't fit. so what uh what's wrong is it too. ambiguous the word information we could.

switch to binary if you want yeah no i. don't think it's binary either i think. information is just loaded i use it so. the other way i might talk about it is. the physics of causation but i think. that's worse because causation is even. more loaded word than. um. information causation is fundamental you. think i do yeah and um in some sense i. think the physics so this is the really. radical part some sense like when i. really think about it sort of most. deeply uh what i think life is is. actually the physics of existence what.

gets to exist and why um and you know. for simple elementary particles that's. not very complicated because the. interactions are simple but for things. like um you know you and me and human. civilizations. um you know what comes next in the. universe is really dependent on what. came before and there's a huge space of. possibilities of things that can exist. and when i say information and causation. what i mean is why is it that. cups evolved in the universe and not. some other object that could deliver. water and not spill it. i don't know what you would call it uh.

maybe it wouldn't be a cup but um but. it's a huge it it's um. you know you know people talk about the. space of things that could exist as. being actually infinitely large right i. don't know if i believe in infinity. um but i do think that. there is something very interesting. about. the problem of what exists in its. relationship to life so do you think. this. the set of things that could exist is. finite. it's very large but like if we were to. think.

about the physics of existence. like how how many shapes of mugs can. there be like is uh. in the initial programming i should go. to the math department for that but. so that's not a topology question i just. mean. maybe another way to ask is what do you. think is fundamental to the universe and. what is emergent so if existence i was. supposed to think of that as somehow. fundamental you think so there's a. couple problems in physics that i think. this is related to one is why does.

mathematics work at describing reality. so well. um and then there is this problem of we. don't understand why the laws of physics. are the way they are or why certain. things get to exist or. what put in place the initial condition. of our universe right there's all of. these sort of really deep and big. problems and they they all um. indirectly are related i think to the. same kind of thing that um. you know our physics is really good if. you specify the initial condition at. specifying a certain sequence of events.

but it doesn't deal with the fact that. other things could have happened which. is kind of an informational property. like a counter factual property. um. and it's not good at explaining. uh. you know this conversation right now. it's just it there are certain things. that are outside the explanatory reach. of current physics and. um i think they require looking at it. from a completely different direction. um and so i don't want to have to. fine-tune the initial condition of the. universe to specify precisely all the.

information in this conversation i think. that's a ridiculous assertion um but. that's sort of like how people want to. frame it when they talk about. um. you know the standard model is. sufficient if we had computing power to. basically explain all life in our. existence an interesting thing you said. is the way we think about information. computation is by observing a particular. kind of systems on earth. that exhibit something we think of as. intelligence but that's. that's like uh looking at i guess the.

tip of an iceberg and we should be. really looking at the fundamentals of. like the iceberg like like like what. makes. water and ice and and and the chemistry. that from which intelligence emerges. essentially. we can't just couple the information. from the physics and i think that's what. we've gotten really good at doing. especially with. sort of. the modern age where you know software. is so abstracted. um from. hardware. but the entire process of biological.

evolution has basically been built like. been building layers of increasing. abstraction and so it's really hard to. see that physics in us but it's much. clearer to see it in molecules. yeah but i guess i'm trying to figure. out what what do you think are the best. tools to look at it. what do you think. an open mind is that a tool. what's the physics of an open mind. i think if we saw that we'll solve. everything i'm saying an open mind. because i think the biggest stumbling.

block um. to understanding sort of the things i've. been trying to articulate or and when i. talk also with colleagues that are. thinking deeply about these same issues. is. none of it is inconsistent with what we. know it's just such a radically. different perception perception of the. way we understand things now that it's. hard for people to get there and in some. ways you have to almost forget what. you've learned in order to learn. something new right so i feel like most. of my career trying to understand the. problem of life has been variously.

forgetting and then relearning things. that i learned in physics and and i. think you have to. you have to have a capacity. to learn things but then accept that. things that you were you you learned. might not be true. um. or. or might need refinement or reframing. um. and the best way i can say that is just. like with a physics education there are. just certain things you're told in. undergrad that are like facts about the. world. and your physics professors never tell.

you that those facts actually emerge. from a human mind right so we're taught. to think about say the laws of physics. for example. as this like. autonomous thing that exists outside of. our universe and tells our universe how. it works yeah um but the laws of physics. were invented by human minds to describe. things that are regularities in our. everyday experience. right they don't exist autonomous to the. universe right so it's like turtles on. top of turtles but. eventually gets the human mind and then. you have to explain the human mind with. the turtles yes so you have to yeah it.

comes from humans this understanding the. simplification of the universe these. models yeah there's a guy named stephen. wolfram there's a. concept called cellular automata so. there's a. there's some mysteries in these um. systems that are computational in nature. that have. maybe echoes. of the kind of mysteries we should. need to solve to understand what is life. [Music]. so.

if we could talk take a. computational view of things do you. think there's something compelling to. reducing everything down to computation. like the universe is computation and. then trying to understand. life so. throw away the biology throw away the. chemistry throw away even the physics. that you you learn undergrad in graduate. school and more look at these simple. little systems whether it's cellular. automata or whatever the heck kind of. computational systems that operate on.

simple local rules and then create. complexity. as they evolve. is is it uh at all do you think. productive to focus on those kinds of. systems to get an inkling of what is. life. and if it is. do you do you think it's. it's possible to come up with some kind. of laws and principles about what makes. life in those computational. systems. so i like cellular automata i think. they're good toy models um but mostly.

like where i've thought about them and. use them is to actually. um. [Music]. let's say poke at sort of the current. conceptual framework that we have and. see where the flaws are. um so i think like the part that you're. talking about that people find. intriguing is that if you have like a. fairly simple rule. and you specify some initial condition. and you run that rule and that initial. condition you could get really complex. patterns emerging and ooh doesn't that. look lifelike um. yeah.

well it's like really surprising isn't. it it is really surprising and they're. beautiful um and i i think they have a. lot of nice features associated to them. um i think the things that i find yeah. so so i i do think um as a proof of. principle that you can get complex. things emerging from simple rules. they're great. um as a sort of proof of principle about. some of the ways that we might think of. computation as being sort of a. fundamental principle for dynamical.

systems and maybe the the evolution of. the universe as a whole they're a great. model system. as an explanatory framework for life i. think. they're a bit problematic for the same. reason that. the laws of physics are a bit. problematic um and the clearest way i. can articulate that is like cellular. automata are actually cast in sort of a. conceptual framework for how the. universe should be described that goes. all the way back. to newton in fact with this idea that we.

can have a fixed law of motion. which exists sort of it's given to you. you know the great programmer in the sky. gave you this equation. or this rule and then you just run with. it um and the rule doesn't have so a. good feature of the rule is it doesn't. have specified in the rule information. about the patterns it generates so you. wouldn't want for example the my cup or. my water bottle or you know me sitting. here to be specified in the laws of. physics that would be ridiculous because. it wouldn't be a very simple explanation.

of all things happening i'd have to. explain everything. so and tell your time to have that. feature. and the laws of physics have that. feature. um but but you know you also need to. specify the initial condition um and it. also it basically means that everything. that happens is sort of a consequence of. that initial condition and i think this. kind of framework is just not the right. one for biology um and part of the way. that it's easiest to see this is. um a lot of people talk about.

self-reference being important in life. the fact that um you know like the. genome has information encoded in it. that information gets read out. um it specifies something about the. architecture of a cell. the architecture of the cell includes. the genome so the genome has basically. self-referential information. self-reference obviously comes up in. computational law because it's kind of. foundational um to turing's work and. what girdle did with the incompleteness. theorems and things so there's a lot of.

parallels there and and people have. talked about that at depth um but the. other way of kind of thinking about it. in terms of like a more physics-y way of. talking about it. is that what it looks like in biology is. that the rules or the laws depend on the. state this is typical in computer. science this is obvious to you you know. the update rule depends on the state of. the machine right but and you know you. don't think about um. uh you know that being sort of the. dynamic and physics it's you know the. rules given to you and then it you know. it's a it's a very special subclass say.

of computations if. you know you don't ever change the. update um but in biology it seems to be. that the state and the law change. together as a function of time and we. don't have that as a paradigm in physics. and so a lot of people talked about this. as being kind of a perplexing feature. that maybe there are certain scenarios. where the laws of physics or the laws. that govern a particular system actually. change as a function of state of that. system that's trippy so yeah the the. hope of physics it's a hope i guess but.

often stated as a. underlying assumption is that the law. is uh static right. okay and even having laws that vary in. time and not even as a function of the. state is very radical. when you the time in general like yeah. you want to remove time from the. equation as much as possible yeah i i do. um there's some interesting things in. this like when we think it's sort of. deep more deeply about the actual. physics that we're trying to propose. governs life um with me with.

collaborators and then also other people. that think about similar things that. time might actually be fundamental and. there really is an ordering to time. um and that events in the universe are. unique because they have a particular. you know they they happen like an object. in the universe requires a certain. history of events in order to exist. which therefore suggests that time. really does have an ordering i'm not. talking about the flow of time and our. perception of time just the ordering of. events causation yes causation there's. that word again. so causation that's when you say time. you mean causation yes.

in your proposed model. of the physics of life the the. fundamental thing would be causation if. you were to bet your money on on one. particular horse or whatever yes and. then space is emergent. yes so everything's emergent except time. kind of yeah or causation. change all the time why it look like. laws are the same laws well because uh. well one way um and i actually this idea. comes from lee cronin because i work.

with him very closely on these things is. that the laws of physics look the way. they do because they're low memory laws. so they don't require a lot of. information to specify them they're very. easy for the universe to implement but. if you get something like me for example. i require 4 billion year history to. exist in the universe i come with a lot. of historical baggage. and that's part of what i am as a set of. causes that exist in the universe. so i have local rules that apply to me. that are associated with sort of the. information in my history. that aren't universal to every object in. the universe.

and there are some things that are very. easily easy to implement low memory. rules that apply to everything in the. universe. so there's no shortcuts to you no i so. yeah i don't believe in like things like. boltzmann brains or. uh you know fluctuations out of the. vacuum that can produce things like your. desk ornaments. i actually think they require a. particular causal chain of events to. exist. well i appreciate the togetherness of. that but uh so how does that.

if we have to simulate the entire. universe to create the ornaments and the. two of us. how are we supposed to create. engineer life yeah that's not. this goes back to sort of the critique. of the rna world i think one of the. problems and i'll get to answering your. question but i think this is kind of. relevant here one of the problems with. the rna world. when we test it in the laboratory is how. much information we're putting into the. experiment. we specify the flasks we make pure. reagents we mix them we take them out we.

put them in the next flask we change the. ph we change the uv light and then we. get a molecule and it's not even an rna. molecule necessarily it might just be a. base right um and so. people don't usually think about the. fact that we're agents in the universe. making that experiment and therefore we. put a little bit of life into that. experiment. um. because it's part of our biological. lineage in the same sense that a couple. or i am a part of the biological lineage. the experimental ideas. are. injecting life yes.

and the constraints that we put on the. experiments because those conditions. wouldn't exist in the universe on planet. earth at that time without us as the. boundary condition right so. even though we're not actually adding. any actual like chemistry or biology. that it could be identified as life. are the constraints we're adding to the. experiment the design of the experiment. yeah you can think of a design. experiment as a program you put. information in it's an algorithmic. procedure that you design the experiment. and so um so the original life problem. becomes one of minimizing the.

information we put into physics. to actually watch the spontaneous. original life can we can we have so can. is it possible in the lab to have an. information vacuum then so like if we. could we would that would be amazing i. don't know that's a good question for. more for lee yeah you guys by the way. for people who don't know lee cronin is. uh. you guys are uh colleagues and uh. i've gotten a chance to listen to the. two of you talking there's great sort of. chemistry and you're brilliant. brainstorming together and there's.

there's a really exciting. community here of of brilliant people. from different disciplines working on. the problem yeah of life of complexity. of uh. i don't know whatever. the words fail us to describe the exact. problem we're trying to actually. understand here intelligence all those. kinds of things. okay so. what what uh. from a lab perspective so lee i guess. would you call him a chemist no i think. by training he's a chemist but i think.

most of the people that work in the. field we do have lost their discipline. that's why i couldn't answer your. question. okay i don't know what you call them. yeah i don't know what i call myself i. don't know what i call any of my friends. so why why is it so hard to create uh. and it's an interesting question to. create biological life in the lab. like from your perspective. is that an important problem to work on. to try to recreate the historical origin. of life on earth or echoes of the.

historical origin i think echoes is more. appropriate i don't think asking the. question of what was the exact. historical sequence of events and. engineering every step in the process to. make exactly the chemistry of life on. earth as we know it is a meaningful way. of asking the question and it's a little. bit like. um you know if. since you're in computer science like if. you know the answer to a problem it's. all it's easier to find a program to. specify the output right but if you. don't know the answer or priority you. know finding an algorithm for like say.

finding a prime or something it's easy. to um you know. uh verify it's a prime number it's hard. to find the next prime um and uh. the way the original life is structured. right now in the historical problem is. you know the answer and you're trying to. retrodict it by breaking it down into. the set of procedures where you're. putting a lot of information in and what. we need to do is ask the question of. how is it. that the rules of how our universe is. structured permits things like life to. exist and what is the phenomena of life. and those questions are obviously.

essentially the same question and so. you're looking essentially for this. missing. physics this missing explanation for. what we are and you need to set up. proper experiments that are going to. allow you to probe. the vast complexity of chemistry in an. unconstrained way with as little. information put in as possible to see. when things. when does information actually emerge. how does it emerge. what is it. and. part of the the sort of conjecture we.

have is. that this physics only becomes relevant. or at least this is this is my personal. conjecture and um and it's sort of. uh validated by this kind of theory. experiment collaboration. um. that we we have working in this area. um that this you know sort of i made the. point about like gravity existing. everywhere right but when you study um. an atomic nucleus you don't care about. gravity it's not relevant physics there. right it's it's weak it doesn't matter. and so. this idea that that there's kind of a.

physics associated with information. for me. it's very. evident that that physics doesn't become. relevant until you need information to. specify the existence of a particular. object and the scale of reality where. that happens is in chemistry because of. the combinatorial diversity of chemical. objects that can exist far outs. exceeds the amount of resources in our. universe so if you want to you can't. make every possible protein of length um. you know 200 amino acids there's not.

enough resources so in order for this. particular protein to exist and this. protein to exist in high abundance means. that you have to have a system that has. knowledge of the existence of that. protein and can build it so existence. comes to be at the chemical level so. existence is most. uh is uh best understood at the chemical. level it's most evident. it's a little bit like nobody argues. that gravity doesn't exist in an atomic. nucleus it's just not relevant physics. there so the physics of information. is everywhere it exists at every.

combinatorial scale but it becomes more. and more relevant the more set of. possibilities that could exist. because you're you're you're you have to. specify more and more about why this. thing exists and not the infinite it's. not an infinite set but you know the set. of undefined set of other things that. could exist so can ask a weird. yeah question which is. so let's look into the future. i try that every day it never works. so say a nobel prize is given in physics.

maybe chemistry. for discovering the origin of life. no not but not the historical origin. some kind of thing that we're talking. about. what exactly. would. what do you think. that like what do you think that person. maybe you did to get that nobel prize. like what would they have to have done. because you could do a bunch of. experiments that go like with an aha. moment.

like you rarely get the nobel prize. for like you've solved everything we're. done right it's like some inkling of. some deep truth right like what do you. think that would actually look like. would it be an experimental result. uh i mean it will have to have some kind. of experimental maybe validation. component so what would that look like. this is an excellent question. i want to. sorry i'm going to make a quick point. which is just a slight tangent but you. know like when people ask about the.

origin of mass you know and like looking. for the higgs mechanism and things they. never like we need to find the. historical origins of life in the early. unit although those things are related. right so um so this problem of origins. of life in the lab i think is really. important but the the higgs is a good. example because you had theory to guide. it so somehow you need to have an. explanatory framework. that. can say that we should be looking for. these features. and explain why they might be there and. then be able to do the experiment and. demonstrate that it matches with the.

theory but it has to be something. that is outside sort of the paradigm of. what we might expect based on what we. know right so this is a really sort of. tall order. um and. i think um. i mean i i guess the way people would. think about it is like you know if you. had a bacteria that climbed out of your. test tube or something and it was like. you know moving around on the surface. that would be ultimate validation you. saw the original life in an experiment. but i don't think that's quite what. we're looking for i think what what. we're looking for is evidence of when.

information that originated within. the bounds of your experiment and you. can demonstratively prove emerge. spontaneously in your experiment wasn't. put in by you. actually started to govern the future. dynamics of that system and specify it. and you could somehow relate those two. features directly so you know that the. program specifying. what's happening in that system is. actually internal to that system like. say you have a chemical thing in a box.

well. so that's that's one nobel prize with. the experiment which is like. information in some fundamental way. originated. within the constraints of the system. without you injecting anything but. another experiment is. you injected something yeah. and got out information yes so like you. injected. i don't know like uh. like some sugar and like something. something that doesn't necessarily feel.

like it should be information yeah so i. actually no i mean sugar is information. right so part of the argument here is. that every physical object. is. well it's information but it's a set of. causal histories and also a set of. possible futures so there's an. experiment um that i've talked a lot. about uh with lee cronin but also with. michael lockman and chris kempies who. are at santa fe about this idea that. sometimes we talk about is like seating. assembly um which is you take a high. high complexity like a an object that.

exists in the universe because of a long. causal history and you seed it into a. system of lower causal history and then. suddenly you see all of this complexity. being generated so i think another. validation of the physics would be. say you engineer an organism by by. purposefully. introducing something where you. understand the relationship between the. causal history of the organism. and the say very complex chemical set of. ingredients you're adding to it and then. you can predict the future evolution of.

that system to some. statistical. uh set of constraints and possibilities. for what it will look like. in the future. you know i'm a physical structure. obviously like i i'm composed of atoms. the configuration of them and the fact. that they happen to be me. is because i'm not actually my atoms i. am a informational pattern that keeps. re-patterning those atoms into sarah um. and i have also associated to me is like.

a space of possible things that could. exist. that i can help mediate come into. existence because of the information in. my history. and so. when you understand sort of that. time is a real thing embedded in a. physical object. then it becomes possible to talk about. how. histories when they interact. and history is not a unique thing it's a. set of possibilities when they interact.

how do they specify what's coming next. and then where does the novelty come. from in that structure because some of. it is kind of things that haven't. existed in the past can exist in the. future. let me ask about this entity that you. call sarah yes i talk to myself about. myself in third person sometimes i don't. know why. uh. so maybe this is a good time to bring up. consciousness sure. it's been here all along. wow. has it so what i mean at least in this. conversation i think i've been conscious.

most of it but maybe i haven't well yeah. speak so speak for yourself you're. you're you're projecting your. consciences onto me you don't know if. i'm conscious or not is it. um you're right is that uh. he talked about the physics of existence. he talked about the emergence of um. of causality uh sorry you talked about. causality and time being fundamental to. the universe. does consciousness fit into all of this. like uh. do you draw any kind of inspiration or.

value with the idea of pan psychism. that maybe one of the things that we. ought to understand is the physics of. consciousness. like. one of the missing pieces. in the physics view of the world is. understanding the physics of. consciousness or like that word. has so many concepts underneath it but. let's put it. let's put consciousness as a label on a. black box of mystery that we don't.

understand. do you think. that black box holds the key. to uh finally answering the question of. the physics of life. the problems are absolutely related i. think um most and i'm interested in both. because i'm just interested in what we. are and to me the most interesting. feature of what we are is our minds and. the way they interact with other minds. like minds are the most beautiful thing. that exists in the universe so how did. they come to be. i'm sorry to interrupt so when you say. we you mean humans i mean humans right. now but i but that's because i'm a human.

i think i am you think there's something. special to this particular no no no um. no um. i don't i'm not a human-centric thinker. but are you one entity you said a bunch. of stuff came together to make a sarah. like. yourself. as one entity are you just. a bunch of different components like is. there any value to understand the. physics of sarah like or are you just a. bunch of different things that are like. a nice little temporary side effect yeah.

you could think of me as a bundle of. information that just became temporarily. aggregated or individual yeah that's. fine i agree with that view. um. okay i think that is a compliment. actually but you you've. but nevertheless that bundle of. information has become conscious or at. least keeps calling her self-conscious. yeah i think i'm conscious right now but. i might not be but that's okay um or you. wouldn't know um so yeah so this is the. problem so yeah usually people when. they're talking about consciousness are.

worried about the subjective experience. and so i think that's why you're saying. i don't know if you're conscious because. i don't know if you're experiencing this. conversation right now. um and nor do you know if i'm. experienced in the conversation right. now. and so this is why this is called the. hard problem of consciousness because it. seems impenetrable from the outside to. know if something's having a conscious. experience um. and i really like um. the idea of also like the hard problem. of matter which is related to the hard. problem of consciousness which is you. don't know the intrinsic properties of.

an electron not interacting say for. example with anything else in the. universe all the properties of anything. that exists in the universe are divine. by its interaction because you have to. interact with it in order to be able to. observe it so we can only actually know. the things that are observable from the. outside and so this is one of the. reasons that consciousness is hard for. science because you're asking questions. about something that's subjective and. supposed to be intrinsic to what that. thing is as it exists and how it feels. about existing. and so.

i have thought a lot about this problem. and its relationship to the problem of. life and the only thing i can come up. with to try to make. that problem. scientifically tractable. and also related to how i think about. the physics of life. is to ask the question. are there things that can only happen in. the universe because. there are physical systems that have. subjective experience. so does subjective experience have.

different causes. that things that it can cause to occur. um. that would happen in the absence of that. i don't know the answer to that question. but i think that's a meaningful ask way. of asking the question of consciousness. i can't ask if you're having experience. right now but i can ask if you having. experience right now changes something. about you and the way you interact with. the world. so. does stuff happen it's just it's a good. question to ask this stuff happen if. consciousness is.

then it's a real physical thing right it. has physical consequences i'm a. physicist i'm biased so i don't you know. i can't get rid of that bias it's really. deeply ingrained um i've tried. but but i mean you're saying information. is physical too so like virtual reality. and stimulation all that program is. physical too yes everything's physical. it's just not physical the way it's. represented in our minds. right so you i love your twitter so you. tweet these like deep thoughts. and deep dust that's what a theorist.

does when she's trying to experiment. is tweet it's just like. sitting there i mean i can just imagine. you sitting there for like hours and all. of a sudden just like this thought comes. out and you get a little um. like inkling into the thought process. yeah usually it's like when i'm running. between things. articulate one of the things you tweeted. is ideologically there are many. parallels between the search for neural. correlates of consciousness and for.

chemical correlates of life how the. neuroscience and astrobiology. communities treat those correlates is. entirely different. can you elaborate against this kind of. yeah the parallels it has to do a little. bit with the consciousness and the. and the matter thing you're talking. about yeah it does and i i can't. remember what state of mind i was when i. was actually thinking about that but um. but i think part of it is but you never. thought you're gonna have to analyze. your own twitter no i didn't it's an.

interesting uh historical juxtaposition. of thinking so the tweet is a historical. uh. you're doing an assembly experiment. right now because you're bringing a. thought from the past into the present. and trying to actually in the lab. yeah yeah this is this is experimental. science right here okay on the podcast. live. um. so so go let's see how the consciousness. evolves on this one yeah so um in. neuroscience it's kind of accepted that. we can't get the subjective. aspect of consciousness so people are.

very interested in what would be a. correlate of consciousness so. um. so. that's a correlation a correlate is a. feature. that relates to conscious activity so. for example um you know a verbal report. is a correlate of consciousness because. um you know i can tell you when i'm. conscious. and then when i'm sleeping for example i. can't tell you i'm conscious so we have. this assumption that you're not. conscious when you're sleeping and. you're conscious when you're awake yeah.

um and so so that's sort of like a a. very obvious example but uh. neuroscientists which you know i'm no. neuroscientist and i'm not an expert in. this field so um but you know they have. very sophisticated ways of measuring you. know activity in our brain and trying to. relate that to verbal report and other. proxies for whether someone is. experiencing something um and that's. what is meant by neural correlates. um and then so when people are trying to. think about. um. studying consciousness or developing.

theories for consciousness they often. are trying to build an experimental. bridge to these neural correlates. recognizing the fact that a neural. correlate may or may not correspond. to consciousness because that problem's. hard and there's all these associated. issues to it. so that that's from a neuroscience. perspective it's like fake it till you. make it so you pretty much yeah you fake. whatever the correlates are and. hopefully that. the uh that's going to uh summon.

the thing that is consciousness or. something like that and so the same. thing on the chemical. correlates of life is it that sounds. like that's an awesome concept is that. something that people no i just made. that up okay that was the originals to. that tweet you can cite the tweet. maybe i'll write it in a paper someday. uh chemical correlates of life that's a. good title i mean first of all your your. papers too that people should check out. have great titles. or paper papers you're involved with. so your tweets and titles are are.

stellar and also your ideas but the. tweets and titles are much more. important of course so these will live. longer. yeah. they're much more diffused though um. well it's yeah it's the. tweet is the trojan horse or the idea. that that sticks on for a long time okay. so is there anything to say about the. chemical coils you're saying. there are similar kind of ways of. thinking about it. but uh. you you mentioned about the communities.

yeah so i think in astrobiology it's not. um. there's no concept of chemical. correlates of life we don't think about. it that way we think if we find. molecules that are involved in biology. we found life. so i think i i i think one of my. motivations there was just to separate. the fact that. life has abstract properties associated. to it they become imprinted in in. material substrates um and those. substrates are correlates for that thing. but they are not necessarily the thing.

we're actually looking for the thing. that we're looking for is the physics. that's organizing that system to begin. with not the particular molecules. um in the same sense that that you know. your consciousness is not your brain. it's it's it. it's instantiated in your brain that you. know it has to have a physical substrate. but it's not the. the matter is not the thing that you're. looking at it's some other at least not. in the way that we have come to look at. matter you know with traditional physics. and things there's there's something. else there and it might be this feature.

of history i was talking about our time. being. actually you know physically represented. there. do you think consciousness can be. engineered. yes. in the same way that life can be well. that was a fast answer i didn't even. think about that that's interesting. you don't have a free will that was no i. do have free will but it's interesting. because some i mean. i you know you know you're backtracking. no no that was predestined yeah no no. no i do believe in free will but i also. think that there's kind of kind of an. interesting um.

you know like what you're you speaking. about consciousness what are you. consciously aware of versus like what is. your subconscious brain actually. processing and doing and and sometimes. there's conflict between your. consciousness and your subconsciousness. or your consciousness a little slower. than your subconscious and intuition is. a really important feature of that and. so a lot of the ways i do my science is. guided by intuition. so when i give fast answers like that i. think it's usually because i haven't. really thought about them and therefore. that's probably. telling me something let's continue the. deep analysis of your tweets.

[Laughter]. you said that determinism in a tweet. determinism and randomness play. important roles in understanding what. life is. so let me ask on this topic of free will. what is determinism what is randomness. and why the heck do they have anything. to do with understanding life. yeah. and you threw free will in there just. throwing all the the stuff in the bag. are they not related no no they are they. are related then no no that's all right. i was being unfair you didn't even.

capitalize the tweet by the way it was. all lower case i must have been angry oh. that was was saying can you analyze the. emotion behind that no i actually did. frustration yeah maybe so. i already argued that i don't think that. can happen without that whole causal. history and so i guess in some sense um. the determinism for me arises because of. the causal history. um and i'm not really sure actually. about whether the universe is random or. deterministic i just had this sort of.

intuition for a long time i'm not sure. if i agree with it anymore but it's. still kind of lingering and i don't know. what to do with this question but it. seems to me you know so there's you ask. the question what is life but you could. also why life why does life exist what. does the universe need life for not that. the universe has needs but you know we. have to anthropocentrize things. sometimes to talk about them um and i. had this feeling that if it was possible. for. a cup or a desk ornament or a phone on. mars to spontaneously fluctuate into. existence the universe didn't need life.

to create those objects it wasn't. necessary for their existence it was. just a random fluke event and so somehow. to me it seems that. it can't be that those things formed by. rand random processes they actually have. to have a set of causes that. accrue and form those things and they. have to have that history and so it. seems to me that that life was. somehow deeply related to the question. of whether the underlying rules of our. universe had randomness in them or they. were fully deterministic and in some. ways you can think about life as being.

the most deterministic part of physics. because it's where the causes are. um. precise in some sense um or most stable. so like most stable yes most reliable. most reliable for for our. for how we for the tools of physics but. what um right well so where's the. randomness come from then if okay so you. you were at. uh speaking with i've gone in a tangent. so i'm not sure where we are in the yeah. all of the universe is a kind of tangent.

so uh we're embracing the tangent so. free will. you believe. at this current time that you have free. will i believe my whole life i have free. will what is illusion. i still believe it you still believe it. so uh at the same time you think that. in your conception of the universe. causality seems to be pretty fundamental. that's right which kind of wants the. universe to be deterministic. so how the heck. because i mean you think you have a free.

will and yet you value causality. um. because i depart from the. conception of physics that you can write. down. an initial condition and a fixed law of. motion and that will describe everything. there's no incompatibility if you are. willing to reject that assertion so. where is the randomness where's the. magic that gives birth to the free will. is it the randomness of the laws of. physics. no free um. in my mind what free will is is the fact.

that i. i as a physical system have causal. control over certain things i don't have. causal control over everything but i. have a certain set of things and i'm. also. um you know as i described sort of a. nexus of a particular set of histories. that exist in the universe on a. particular set of futures that might. exist. and those futures that might exist are. in part specified by my physical. configuration as me. um and. therefore. you know it may not be free will in the. traditional sense i don't even know what.

people mean when they're talking about. free will honestly it's like the whole. discussion is really muddled but in the. sense that i am a causal agent if you. want to call it that that exists in the. universe and there are certain things. that happen because i exist as me. then yes i have free will no but. do you. sarah have a choice about what's going. to happen next oh i see um if the. universe could i have if i run this yes. i think so you have a choice. where's the choice come from is it i.

think that's related to the physics of. consciousness so one of the things i. didn't say about that i don't know maybe. this is me just being hopeful. um because i maybe i just want to have. free will but i don't think that we can. rule out the possibility because i don't. think that we understand enough about. any of these problems but i think one of. the things that's interesting for me. about the sort of inversion of the. question of consciousness that i. proposed. is one of the features that. that we do. is we have imagination right and people. don't think about imagination as a. physical thing but it is a physical.

thing it exists in the universe right um. and so i'm like really intrigued by the. fact that say humans for. you know another physical system could. do this too it's not special to humans. but uh you know for centuries imagined. flying machines and rockets and then we. finally built them right so they were. they were represented in our minds and. on the pages of things that we drew. for hundreds of years before we could. build those physical objects in the. universe. but certainly the existence of rockets. is in part. causally.

you know caused by the fact that we. could imagine them. um and so um. so there seems to be this property that. some things don't exist they've never. physically existed in the universe but. we can imagine the possibility of them. existing and then cause them to exist. maybe individually or collectively um. and i think that property is related to. what i would say about having choice or. free will because that set of. possibilities that thing those set of. things that you can imagine is not. constrained to your local physical. environment and history and this is.

what's a little bit different about. intelligence as we see it in humans and. ai that we want to build than biological. intelligence because biological. intelligence is predicated completely on. the history of things it's seen in the. past but something happened with the. neural architectures that evolved in. multicellular organisms that they don't. just have access to the past history of. their particular you know set of events. but they can imagine things that haven't. happened aren't on their timeline and as. long as they're consistent with the laws. of physics make them happen. so.

this is fascinating. physics but it exists so there you go i. mean in some sense if you look at like. general relativity and gravity morphing. space time. in that same way maybe whatever the. physics of consciousness might be. it might be morphing that's like what. free will is it's morphing like. the space just like ideas make rockets. come to life. it's somehow. changing the space of possible. realizations of like whatever's.

yeah okay but life is kind of basically. if you want to think about it like life. is sort of changing the probability. distributions over what can exist that's. the physics of what life is and then. consciousness is a sort of layered. property your imagination on top of it. that kind of scrambles that a little bit. more and like has you know access to i. don't i don't know it's it's kind of. it we don't know how to describe it. right like that's why it's interesting. but it's probabilistic so you do think. like god plays dice so let me um no i. think the description's probabilistic i.

don't necessarily think. the um. underlying physics is probabilistic i. think i think i think the way that we. can describe this physics is going to be. probabilistic and statistical but the. under like when we take measurements in. the lab but the underlying physics. itself might still be deterministic i. don't. i don't know maybe i'm i it's hard to. know what concepts to hold on to so i. find myself constantly rejecting. concepts but then i have to grab another. one and try to hold on to something from. intellectual history right well it's. possible that our mind is not able to.

hold the correct concepts of mind at all. like right we're not able to even. conceive of them correctly maybe the. words deterministic or random are not. the right even words concepts to be to. be holding but. maybe you can talk to the theory of. everything uh the this attempt in the. current set of physical laws to try to. unify them is there any hope that. once. a theory of everything is developed and. by theory of everything i mean in a. narrow sense of unifying quantum field. area and general relativity do you think.

that will contain some. like in order to do that unification you. would have to get something that would. then give hints about the physics of. life physics of existence. physics of consciousness yeah. i used to not but i actually uh i have. become increasingly convinced that. it probably will. um and part of the reason is um i think. i've talked a little bit already about. these holes in physics like these.

the the theories we have in physics you. know they have problems they have lots. of problems um and they're very deep. problems um and we don't know how to. patch them um and some of those problems. become very evident when you try to. patch um quantum mechanics and general. relativity together. so there is this kind of interesting. feature that some of the ways of. patching that might actually um closely. resemble. uh the physics of life and so the place. where that actually comes up most and. actually we just had a workshop in the. beyond center where i work at arizona. state university.

um and lee smolin made this point that. he thinks that the theory of quantum. gravity when we solve it is going to be. the same theory that gives rise to life. um and i think that i agree with him on. some levels because there's something. very interesting where if you look at. these sort of causal set theories of. gravity where they're looking for space. um. as being emergent. and so space time is an emergent concept. from a causal set which is is also sort. of related i think to what wolfram's. doing with his physics project um it's. the same kind of underlying math that we.

have in in this theory that we've been. developing related to life called. assembly theory um which is you know. basically trying to look at. complex objects like molecules and. bacteria and living things. as. sort of uh. as basically being assembled from a set. of component parts. and that they actually encode all the. possible histories that they could have. in that physical object so the. mathematically all these ideas i think. are related i think a lot of people are.

thinking about this from. different perspectives and then. constructor theory um that david deutsch. and kiara marletto have been developing. is a totally different angle on it but i. think getting at some similar ideas so. it's a really interesting time right now. i think for the frontiers of physics and. how it's relating um to maybe deeper. principles about what life is so short. answer yes long-winded answer rewind. can we talk about aliens. anytime. so one. i think one interesting way to sneak up. on the question of what is life.

is. to ask what should we look for in alien. life. you know if we were to look out into our. galaxy and enter the universe and come. up with a framework of how to detect. alien life. what should we be looking for. is there. like set of rules. uh like it's both the tools. and the tools that are. service census for certain kind of. properties of life.

so what should we look for. in alien life yeah so we have a paper. actually coming out monday which is. collaboration um it's actually really. lee cronin's lab but my group worked. with him on it and we're working on the. theory which is this idea that we should. look. for life um as high assembly objects. what we mean by that is. which is actually observationally. measurable and this is one of the. reasons that i started working with leon. these ideas is because being a theorist. it's easy to work in a vacuum it's very.

hard to connect abstract ideas about the. nature of life to anything that's. experimentally tractable. but what his lab has been able to do is. develop this method where they look at a. molecule and they break it apart into. all its component parts and so you say. you have some elementary building blocks. and you can build up all the ways of. putting those together to make the. original object and then you look for. the shortest path in that space. and you say that's sort of the assembly. number associated to that object.

and if that number's higher it assumes. that a longer causal history is. necessary to produce that object or more. information is necessary to specify the. creation of that object in the universe. now that kind of. idea at a superficial level has existed. for a long time that kind of idea as a. physical observable of molecules is. completely novel and what his lab has. been able to show. is that if you look at a bunch of. samples of non-biological things and. biological things there's this kind of. threshold.

of assembly where. as far as the experimental evidence is. and also your intuitive intuition would. suggest. that by non-biological systems don't. produce things with high assembly number. so this goes back to the idea like a. protein is not going to spontaneously. fluctuate into existence on the surface. of mars it requires an evolutionary. process and a biological architecture to. produce a protein you generalize that. argument you know a complex molecule. or a cup or a desk ornament. in this sort of abstract idea of.

assembly spaces as being the causal. history of objects and you can talk. about the shortest path from elementary. objects to an object given an elementary. set of operations. and you can experimentally measure that. with mass spec and that's basically sort. of the idea that's really fascinating i. can't get out of my head and start. imagining legos and all the legos i've. ever built and how many steps what is. the shortest path to the final right. right to find a little lego castles. so they so yeah so then like asking.

about going to look for alien life the. idea is. you know most the instruments that nasa. builds for example or any of the space. agencies looking for life in the. universe are looking for chemical. correlates of life right but here we. have something that. is based on properties of molecules it's. not a chemical correlate it's agnostic. it doesn't care about the molecule it. cares about. what is the history necessary to produce. this molecule. how complex is it in terms of how much. time is needing how much information is. required to produce it so when you.

observe a thing on another planet you're. essentially. the process looks like reverse. engineering trying to figure out what is. the shortest path to create that thing. yeah so most yeah and i would say most. like most examples of biology or. technology don't take the shortest path. right but the shortest path is a bound. on how hard it is for the universe to. make that yeah and so i guess what you. and lee are saying that there's a. heuristic that's a good. metric for uh like better perhaps than.

chemical correlates yes because it. doesn't it's not contingent on looking. for the chemistry of life on earth on. other planets. and it also has a deeper explanatory. framework associated to it as far as the. kind of theory that we're trying to. develop associated to what life is and i. think this is one of the problems i have. in my my field personally in. astrobiology is people observe something. on earth say oxygen in the atmosphere or. an amino acid in a cell and then they. say let's go look for that on another.

planet. let's look for oxygen on exoplanets or. let's look for amino acids on mars and. then they assume that's a way of looking. for life. um. and it. or even phosphine on venus but you know. like there's all these examples of let's. look for one molecule a molecule is not. life life is a system that patterns. particular structures into matter that's. like it's that's what it is and it. doesn't care what molecules are there. it's something about the patterns and. and that structure and that history um.

and if you're looking for a molecule. you're not testing any hypotheses about. the nature of what life is it doesn't. tell me anything if we discover oxygen. and exoplanet about what kind of life is. there just oxygen on an exoplanet it's. not there there's. i i guess i think like when you think. about the question are we alone in the. universe that's a pretty freaking deep. question it should have a freaking deep. answer it shouldn't just be there's a. molecule and an exoplanet wow we solved. the problem it should tell us something. meaningful about our existence and i. feel like we've fallen short on how. we're searching for life in terms of.

actually searching for things like us. in this kind of deeper way. but how do you do that initial kind of. say i'm walking down the street and i'm. looking for that double take test of. like. like what the hell is that like that. that initial. like how do we look for. the possibility of weirdness at the. possibility of high assembly number well. yeah.

if they don't have two eyes and are. green. you know i would have probably already. solved the problem right there's another. nobel prize in there somewhere i think. actually. um. well i think it's it's kind of so so. there is a bias here right so. we've evolved to recognize life on earth. right like i you know children at a very. early age can tell the difference. between a puppy and a plant and then the. plant and a chair for example you know. like it just it seems innate um and so i. think and also because we're life. um. you know i think like there's this.

implicit bias that we should know it. when we see it and it should be. completely obvious to us. um but there are a lot of features of. our universe that are not completely. obvious to us like the fact that this. table is made of atoms and that i'm. sitting in a gravitational potential. well right now um and i guess um. my point with this is i think life is. much. less obvious than we think it is. and so it could be in many more forms. than we think it is um and i guess let's. go back to the point about being. open-minded that we may not know what.

alien life looks like it might not even. be possible to interact with alien life. because maybe. something about you know our our. informational lineage it makes it. impossible for information from an alien. to be copied to us therefore there's no. you know. so to speak communication channel and i. don't mean you know verbal communication. just. it's not in our observational space like. you know like you know there's there's. fundamental questions about why we. observe the universe in position rather. than momentum but we also you know.

observe it in terms of certain. informational patterns and things like. that's what our brain constructs and. maybe aliens just interact with a. different part of reality than we do. that's wildly speculative but i think i. think um. it's possible it's possible and i think. it's consistent with the physics so i. think the best ways we can ask questions. are about. life and chemistry and asking questions. about if information is a real physical. thing what would its signatures be in. matter. um. and and how do we recognize those and i. think the ones that are most obvious are.

the ones i've already articulated you. have these objects that seem completely. improbable for the universe to produce. because the universe doesn't have the. design of that object in the laws. so therefore an object had to evolve. we we talked we call it evolution but it. had to be produced by the universe that. then had all of the possible tasks to. make that object. um specified i mean there's some like. there's an engineering question here of. are there sensors we can create that can.

give us uh. can help us discover certain pockets of. high assemblies yeah aliens. like. i mean there is a hope. setting dogs and chairs aside. there's a hope that visually. and we could detect. like. because our universe i mean at least the. way we look at it now like this. three-dimensional like space-time. we can visually comprehend it. it's interesting to think like if we got.

to hang out you know if there's an alien. in this room. like would we be able to detect it with. our current sensors not the fancy kinds. but but like what you're standing over. there. yeah standing over there or maybe like. in this carpet see there's all these. kinds of patterns right yeah uh i don't. know. if if. i don't know if this carpet is an alien. well so. i see what you're saying um. so assembly theory is pretty general. like i mean we've been applying it to. molecules because it makes sense applied.

to molecules but it's supposed to. explain life. um you know like the physics of life so. it should explain you know the things in. this room in addition to molecules um so. i guess uh and you can apply it to. images and things so i guess the idea. you know you could explore is just. looking at everything on planet earth in. terms of its assembly structure and then. looking for. things that aren't part of our. biological lineage if they have high. assembly they might be aliens on earth i. mean that that is a very kind of.

rigorous computer vision question can we. visually. is there a strong correlation. between certain kind of high assembly. objects when they get to the scale where. they're visually observable. and. some like when it's. say uh projected onto a 2d plane can we. right can we figure out something right. i am glad you brought up a computer. vision point because for a while i had. this kind of thought in my mind that we. can't even see ourselves clearly so one. of the things you know people are. worried about artificial intelligence. for a lot of reasons but i think it's. really fascinating because it's like the.

first time. in history that we're building a system. that can help us understand ourselves. so like you know people talk about ai. physics but like um. you know when i when i look at another. person i don't see them as a four. billion year lineage but that's what. they are and so is everything here right. so. imagine that we built artificial systems. that could actually. see that feature of us. what else would they see. and i think that's what you're asking. and i think i think that would be so.

cool. i want that to happen but i think i. think we're a little ways off from it. but yeah. we're going there i hope. okay let me ask you uh i apologize ahead. of time but let me ask you the internet. question so you're a physicist you ask. rigorous questions about the physics of. existence and. these models of high assembly objects. now when the internet would see an alien. they would ask two questions one can i. eat it and two can have sex with it yes.

so. so you kind of mentioned that it's very. difficult it's possible that we may not. be even able to communicate with it. right but i think the internet has more. hope than we do yes it's a hopeful place. yes uh do you. do you think in terms of like. interacting on this very primal level of. of sharing resources like what would. aliens eat what would we eat would we.

eat the same thing would could we. potentially eat each other uh one one. person eats the other or or the aliens. eat us and the same thing with. not sex in general reproduction but. genetically mixing stuff like would we. would be able to mix genetic information. maybe not genetic but maybe information. right and i think part of your question. is like so. so if you if you think of life as like. this history of events that happen in. the universe like there's this question. of like how divergent are those. histories right so when we get to the. scale of technology it's possible to.

imagine. imagine although we can't even do it. like imagine all the possible. technologies that could exist in the. universe but if you think about all the. possible chemistries somehow that seems. like a lower dimensional space and a. lower set of possibilities so it might. be that like when we interact with. aliens we do have to go back to those. more. basal levels to figure out sort of what. the map is. right um like the sort of where we have. a common history we all we must have a. common history somewhere in the universe. but in order to be able to actually.

interact in a meaningful way you have to. have some shared history i mean the. reason we can exchange genetic. information in each other's food or eat. each other as food. is because we have a shared history so. we have to find that shared history the. other we have to find the common. ancestor in this causality map the the. something yes. yes and we have a last universal common. ancestor for all life on earth which i. think is sort of the nexus of that. causality map for life on earth but the. question is where would other aliens. diverge on that sound. and i mean.

that. so say there's a lot of aliens out there. in the universe each each set of. organisms will probably have like a. number you know like erdos number of. like. how far. like how far our common ancestor is and. so the closer the common ancestor like. it is on earth. the more like each other the more likely. we are to be able to have sexual. reproduction well it's like sort of like. humans having common culture and. languages right yeah exactly language. communication.

it might take a lot of work though with. an alien because you really have to get. over a language barrier. oh boy so it says communication it's uh. uh resources i mean it's all the whole. and i think tied into that is the. questions of like who's gonna harm who. right and actually definitions parents. approve you know all those kind of. questions. whether the common ancestor approves. yeah that's just very true uh. how many alien civilizations do you. think are out there.

i don't have intuition for that. um which i i have always thought was. deeply intriguing so and and part of. this uh. i mean i say it specifically is i don't. have intuition for that because it's. like one of those questions that you. feel around for a while and you really. just you you can't see it um even though. it might be right there and. um. in that sense it's a little like the. quantum to classical transition you're. like really talking about two different. kinds of physics and i think that's kind. of part of the problem once we. understand the physics that question.

might become more meaningful. um but there's also this other issue um. uh and this was really instilled in me. by my mentor paul davies when i was a. postdoc because he always talks about. how you know whether aliens are common. or rare is kind of just um you know it's. like you know it follows a wave of. popularity and it just depends on like. the mood of you know what the culture is. at the time and i always thought that. was kind of an intriguing observation. but but also there's this you know set. of points about if you go by. observational evidence which we're.

supposed to do with scientists right um. you know. we have evidence of. us. and one original life event from which. we emerged and people want to make. arguments that because that event was. rapid. or because there's other planets that. have properties similar to ours that. that event should be common but you. actually can't reason on that because. our existence observing that event is. contingent on that event happening which. means it could have been completely. improbable or very common. and brandon carter like clearly.

articulated that in terms of anthropic. arguments um. a few decades ago so so there is this. kind of issue that we have to contend. with dealing with life that's closer to. home than we have to deal with with any. other problems in physics which we're. talking about the physics of ourselves. and when you're asked about the original. life event that event happening in the. universe at least is like our existence. is contingent on it um and so you can. think about sort of fine tuning. arguments um. that way too so um but the the sort of. odder part of it is like when i think.

about. uh how likely it is i think it's because. we don't understand this mechanism yet. about. how information can be generated. spontaneously. that i like because i can't see that. physics clearly yet even though i have a. lot of. you know like some things around the. space of it in my mind i can't. articulate how likely that process is. um so my honest answer is i don't know. and it sometimes feels like a cop-out. but i feel like that's a more honest. answer and a more meaningful way of. making progress than um what a lot of.

people want to do which is say oh well. we have a one-in-ten chance of having on. an exoplanet with earth-like properties. because there's lots of earth-like. planets out there and life happen fast. on earth well so. i have kind of a follow-up question but. as a side comment. what i really am enjoying about the way. you're talking about human beings is you. always say not to make yourself. conscious about it because i really. really enjoy it do you say we. yes you don't say humans. you say because often times like and you. know i don't know evolutionary.

biologists will kind of. put yourself out. yes as an observer but you're. it's it's kind of fascinating to think. that you as a human are struggling about. your own origins. yes that's the problem and yeah and i i. think um i don't do that deliberately. but i do think that way and this is sort. of the inversion from the logic of. physics because physics as it's always. been constructed has treated us as. external observers of the universe and. we are not part of the universe and this. is why the problem of life i think. demands completely new thinking because.

we have to think about ourselves as. minds that exist in the universe and are. at this particular moment in history and. looking out at the things around us and. trying to understand what we are inside. the system not outside the system we. don't have descriptions at a fundamental. level that describe us as inside the. system and this was my problem with. cellular automata also you're always an. external observer for a cellular. automata you're not in the system what. does the cellular automata look like. from the inside. i think you just broke my brain with.

that question exactly but i thought. about that for a long time. i'm gonna. uh yeah that's a that's a really clean. formulation of a very fundamental. question because you can only to. understand cellular autonomy you have to. be inside of it. but as a human sort of a poetic romantic. question does it make you sad does it. make you. hopeful. whether we're alone or not like in the. different possible versions of that.

if we're the highest assembly object in. the entire universe. does that at this moment in time at this. moment in the causality because we might. i assume we have a future well we. definitely have a future and the. question is well yeah where that future. decreases the assembly like it could be. where at the peak. or we could be just um. that would be inconsistent with the. physics in my mind but. so so i i should give a caveat i've. given the the caveat that i'm biased as.

a physicist but i'm also biased as an. eternal optimist so pretty much all of. my modes of operation for building. theories about the world are not like an. occam's razor what's the simplest. explanation but what's the most. optimistic explanation. and part of the reason for that is if. you really think explanations have. causal power. um in the sense that our theo like the. fact that we have theories about the. world has enabled technologies and. physically transformed the world around. us i think i have to take seriously that. as a part of the physics i want to.

describe. and try to. build. theories of reality that are optimistic. about what's coming next because the. theories are in part the causes of what. comes next. so there could be a physics of. hope or physics of optimism in there too. yes. because um. that seems like also i mean optimism. does seem to be a kind of engine that. results in innovation yes so this is dr. like what why the hell. are we trying to come up with new stuff.

oh so um so i made this point about. thinking life is the physics of. existence and it's not just the physics. of existence it's the physics of. more things existing. so i think one of these drives. the yeah creativity like optimism the. story so if you like people like entropy. i don't i don't like entropy as it was. formulated in the 1800s i think it's an. antiquated concept but um but this idea. of maximizing over the possible number. of states that could exist imagine the. universe is actually trying to maximize.

over the number of things that could. physically exist what would be the best. way to do that the best way to do that. would be evolve intelligent. technological things that could explore. that space. so okay that's talking about alien life. out there in the universe but you've. also earlier in the conversation. mentioned. the shadow biosphere so is it possible. that we have weird life here. on earth that we're just not. like even in a high assembly formulation.

of life yeah that we're just not. paying attention to we're blind to like. life we're potentially able to detect. but we're blind to and maybe you could. say what is the shadow bias sure sure. yeah the shadow biosphere is this idea. that there might have been other. original life events that happened on. earth. that were independent from the original. life event that led to us and all of the. life that we know on earth and therefore. there could be aliens in the sense they. have a different origin event.

living among us um uh and it was. proposed by a number of people um. but one of them was a paul davies that i. mentioned earlier as my mentor and he. has a really a cute way of saying that. aliens could be right under our noses or. even in our noses. uh with a british accent it sounds. better but um but uh but anyway so the. idea is like it could literally be. anywhere around us um and if you think. actually about the discovery of like. viruses and bacteria you know for a long.

time we didn't they were kind of a. shadow biosphere it was life that was. around us but invisible. um and. but this takes it a little bit further. in saying that you know all of those. examples viruses bacteria and everything. that we've discovered so far has this. common ancestry in the last universal. common ancestor of life on earth so. maybe there was a different origin event. and that life is weirder still. and might be among us and we could find. it. we don't have to go out and stars live. for aliens just here on earth do you.

think that's a serious. possibility that we should explore with. the tools of science like this should be. a serious effort i think um yes and no. um and. i mean yes because i think it's a. serious hypothesis um and i think it's. worth exploring and it is certainly more. economical to look for. signs of alien life on earth than it is. to go and build spacecraft and send. robots to other planets and that was one. of the reasons it was proposed is well. if we do find an example of another.

original life on earth it's hugely. informative because it means the. original life is not a rare event if it. happened. twice on the same planet that means it's. probably pretty probable given. conditions are right. um so it has huge potential scientific. impact not to mention the fact that you. might have like biochemistry and stuff. that's informative for like medicine and. stuff like that but. um. but i think that the thing for me that's. challenging about it and this really. comes from my own work like thinking. about. life as a planetary scale process and. also trying to understand.

sometimes what i call like the. statistical mechanics of biochemistry. but large scale statistical patterns in. the chemistry that life uses on earth. there are a lot of regularities there. and life does seem to have planetary. scale organization that's consistent. even with some of the patterns that we. see at the individual scale so if you. think life is a planetary scale. phenomena and the chemistry of life has. to be sort of. um. not just it's not an individual is not. necessarily the fundamental unit of life. right the fundamental you know life is.

these uh informational lineages and. they're kind of you know they intersect. over. spatial scales so everything on earth is. kind of related by the common causal. history yeah so it's hard for me. based on the way i think about the. physics and also some of the stuff that. my group has done to really think that. there could be. uh evidence or there could be a second. sample of life on earth but i think. there are ways that we need to be more. concrete about that and i have thought a. little bit about like um you know like.

you can represent the chemistry in an. individual cell as a network and then. those networks something my group has. shown. actually scale. with the same properties so ecosystems. have the same properties as individuals. as planetary scale and then you could. imagine if you had alien chemistry. intermixed in there that scaling would. be broken so if there's some robustness. property or something associated to it. and you get alien chemistry in there it. just breaks everything and you don't. have a planetary ecosystem functioning.

an individual's functioning across all. these scales so i guess what i'm arguing. is life is not a scale-dependent. phenomena it's not just cellular life so. if you have a shadow biosphere it has to. be integrated with all of these other. scales in it and that and that would. lose the meaning of the word shadow. biosphere i think so yeah so so i i it's. an open question right and i think it. would it would tell us a lot so there. has been very minimal effort of people. to look for a shadow biosphere. but then the question it could be. possible that uh.

there's like sufficiently distinct. planets within one planet meaning like. environments within one planet yeah like. i don't know. i've been looking uh recently. uh because of having a chat with. catherine declare about io the moon of. jupiter that's like all volcanoes and. volcanoes a badass but like yeah. imagining. [Laughter]. imagining life inside volcanoes right. like yeah it seems like sufficiently.

chemically. different. like to be living in the darkness right. where there's a lot of heat and maybe. you could have different earths on like. a planet yeah or like if you go deep. enough in the crust maybe there's like a. layer where there's no life and then. there's suddenly life again and maybe. those you know lizard. men or whatever that people dream about. are really down there um i know that's a. little flippant but but really like. there could be like chemical cycles deep. in those crests that might be alive and. are completely distinct in chemical or.

origin to surface life. right that they wouldn't be interacting. with each other yeah and that's one of. the proposals for the shadow biosphere. is like sometimes people talk about it. as being geologically or geographically. distinct that it might be you know you. have no life for this region and then a. different example and then sometimes. people talk about it being chemically. distinct that the chemistry is. sufficiently different that it's. completely orthogonal or non-interacting. with our chemistry it seems to me at. least the chemistry is. a a more powerful. boundary yes than than than geographic.

it just seems like life. finds a way literally to travel yeah. yes. what do you think about all these ufo. sightings so to me it's really inspiring. it's yet another. localized way to dream about right the. mysterious that is out there yeah. so i've actually been more intrigued by. the cultural phenomena ufos than the. phenomena ufos themselves because i. think it's intriguing about how.

uh. we are preparing ourselves mentally. for understanding others and how we have. thought about that historically and what. the sort of. modern incarnations of that are um. it's more like. i want an explanation for us that's my. motivation and having some you know. streaks across the sky or something and. saying that's aliens it doesn't tell you. anything. um so unless you have a deeper. explanation and you have you know more. lines of. uh you know where is this going to take.

us in the future it's just not as. interesting to me as the problem of. understanding life itself and aliens as. a more general phenomenon i do think. it's uh just as you said. a good way to psychologically and. sociologically prepare ourselves to sort. of like what would that look like right. and very importantly which is what a lot. of people talk about politically. sort of uh there's this idea from the so. it came from the soviet union of like. the cold war and we have to hide secrets. yeah there's some way in us searching.

for life on other planets are searching. for life in general. the. the way we've done government in the. past yeah we tend to think of all new. things as potential military secrets so. we want to hide them. and one of the ways that people kind of. look at ufo sightings is like. like maybe we shouldn't hide this stuff. like what is the government hiding right. i think that's a really. you know in one sense it's a. conspiratorial question but i think.

in another it's an. inspiration to change the way we do. government to where secrets don't uh. maybe there are times when you want to. keep secrets as military secrets but. maybe we need to release a lot more. stuff and see us as a human species as. together in this whole search yeah the. public engagement part there is really. interesting. and it's almost like a challenge to the. way we've done stuff in the past in. terms of keeping secrets when they're. not so like.

the the first step if you don't know how. something how something works if there's. a mysterious thing the the first. instinct should not be like let's hide. it put it in the closet right so that. the chinese or the russian government or. whatever government doesn't uh doesn't. find it maybe the first one the first. instinct should be let's understand it. yeah perhaps let's understand it. together right. no i think that's good and and something. i realized recently that i never thought. was going to be a problem but i think.

this actually helps with quite a bit. is because so many um people nowadays. believe we've already made contact. that. as an astrobiologist if we you know. actually want to understand life and. make contact we kind of have to. deconstruct. the narratives we've already built from. ourselves and kind of unteach ourselves. that we've learned about aliens and then. reteach ourselves so there's this really. interesting sort of dialogue there um. and making it open to the public that. they actually have to think critically. about it and they see the evidence for.

themselves i think is really important. for that process. yeah the restriction that aliens might. be way weirder than we can imagine yes. yes i'm i'm pretty sure they're probably. weirder than we can imagine. okay we've uh in 2020. and still living through a pandemic. setting the the the the political and. all those kinds of things aside i've. always found. viruses fascinating. as as living. as.

dynamical systems i was going to say. living systems but. i've always kind of thought of them as. living you know but that's a whole. nother kind of discussion maybe. it'd be great to put that on the table. one do you find viruses. beautiful slash terrifying and two do. you think they're living. things. or there's some aspect to them. for our discussion of life that makes. them living. i mean living in a pandemic saying. viruses are beautiful is probably a hard.

thing but i do find them. beautiful to a degree i think. even even even in the sense of mediating. a global pandemic there's something like. deeply intriguing there because. you know these these are tiny. tiny little things right and yet they. can um. uh you know essentially um. like cause a seizure like you know. handicap an entire civilization at a. global scale so just that intersection. of between you know our perceived. invincibility and our susceptibility to.

things and also the interaction across. scales of those things is just. a really amazing feature of our world. most technology whether it's viruses or. ai. that can scale scale in an exponential. way like right kind of run. you know like. as opposed to like one thing makes. another thing. makes another thing it's one thing makes. two things and those two things make. four things and then like that kind of. process.

also seems to be fundamental to life yes. and uh. it's terrifying because in in a matter. of in a very short time scale. it can uh. if it's good at being life. whatever that is yeah it can quickly. overtake the the other competing forms. of life right. and that's scary both for ai and. for viruses and it seems like. understanding these processes.

that are underlying viruses and i don't. mean like on the virology or biology. side but on some kind of. more computational physics yeah. perspective as we've been talking about. yeah seems to be really important to. figure out how humans can. survive. right. along with these kinds of. this kind of life and perhaps becoming a. multi-planetary species is. is a part of that like there's no maybe.

like what we'll figure out from a. physics perspective is like there's no. way. any living system. can be stable for a prolonged period of. time and survive unless it expands. exponentially throughout like. we have to multiply otherwise. anything that doesn't multiply. exponentially will die eventually maybe. that's a fundamental law. um. maybe. i don't know i you know i always get. really bothered by these darwinian. narratives that are like you know like. the fittest replicator wins and things.

and i don't i just don't feel like. that's exact exactly what's going on i. think like the copying of information is. sort of. ancillary to this other process of. creativity. right so like the drive is actually the. drive is creativity but if you want to. keep the creativity that's existed in. the past it has to be copied into the. future. right so replication like if you. so that for me is. so i had this set of arguments um with. michael lachman and lee cronin about the. like life being about persistence they. thought it was about persistence and.

like survival of fittest kind of thing. and i'm like no it's about existence. it's like because when you're talking. about that it's easy to say that in. retrospect you can post select on the. things that survived and then say why. they survived. but um but you can't do that going. forward. that's really profound. that survival is just a nice little. side effect feature of. maximizing creativity but it doesn't. need to be there yeah. i like people yeah yeah like i said i.

like optimistic theories well i don't. know if that's up to me that that could. be terrifying to people because. yeah because uh you know a system that. maximizes creativity may very quickly. get rid of humans for some reason if it. comes up with some other creative. i mean yeah. forms of existence. yeah right this is the ai thing it's. like the moment you have an ai. system that can. that can flourish in the space of ideas. or in some other space much more.

effectively than humans. and it's sufficiently integrated into. into the physical space to be able to. modify the environment. i think we'll just be like the core. genetic architecture or something we'll. be like the dna for ai right it's like. we haven't lost the past informational. architectures on this planet they're. still there. yeah also they'll ai will use our brains. in some part to like like ride like. it'll accelerate the exchange of ideas. that's the neural link dream is that.

well the humans will be still around. because you're saying architecture yeah. but i don't i don't even think they. necessarily need to tap in our brains i. mean just collectively we do interesting. things what if they were just using like. the patterns in our communication or. something. oh. without controlling it just. observing well i i don't know in what. sense do you control the chemistry. happening in your body. hmm. yeah. i i mean i i obviously i don't know i'm. just i i just. like the way i look at like people look.

at ai and then they look at this thing. that's bigger than us and is coming in. the future and is smarter than us. and i think though that looking at the. past history of life on the planet and. what information has been doing for the. last four billion years is probably very. informative to asking questions about. what's coming next. um. and i don't. one is planetary scale transitions are. really important for new phases so the. global internet and sort of global. integration of our technology i think. it's an important thing so that's again. life is a planetary scale phenomena but.

we're an integrated component of that. phenomenon i don't really see that the. technology is going to replace us. in that way it's just going to keep. scaffolding. and building and and i also don't have. an idea that we're going to build ai in. a box i think ai is going to emerge agi. to be is a planetary scale phenomena. that's going to emerge from our. technology. planetary scale phenomena but do you. think. an agi is not distinct from humans we're. the whole package the whole package. comes as a planetary scale phenomenon.

and that goes back to the fact that like. you were you know asking questions about. you as an individual. like what are you as an individual. you're like a packet of information that. exists in the particular physical thing. that is you we're all just. packets of information and some of us. are aggregates in certain ways but it's. all just kind of exchanging and. propagating right and processing. is your. packet of information that you've. continually referred to as sarah. afraid. of the dissipation of the. death of that packet are you afraid of.

death. do you ponder death. does death have meaning in this process. of creativity i think i have the natural. biological urge that everyone has to. fear death. um. i think the thing that i think is. interesting is if i think about it. rationally. i'm not necessarily afraid of death for. me because i won't be aware of being. dead. um but i am afraid like for my kids. because it matters to them if i die. um so.

so again like i think death becomes more. significant as a collective property not. as an individual one. yeah but isn't there something to fear. about. the fact that the way. like. the creative uh. the complexity of information that's. been like created in you yeah the the. fact that it kind of. breaks apart. and disappears. it doesn't but i don't think it. disappears it's just not me anymore.

right so you're but the that process of. you it being not you anymore that. doesn't scare you. of course it does the mystery of it i. mean the yeah but i guess i'm heartened. by the fact that there will be some. imprints of the fact that i existed. still in the universe after i leave it. yeah but there'll be a okay and also. that has to do with my perception of. time right so you know i perceive time. as flowing but that might not be the. case. i mean this is you know standard. physicists comfort is you know every.

time moment exists you know and is you. know there's no and the flow of time is. just our perception of. you know us um you know us changing. um. so you can travel back in time and. that's comforting like from a physics. condition no no i'm not talking about. traveling back in time i'm just saying. that the moments in the past still exist. um now whether the moments in the future. exist or not is a different question. that's not comforting to me in terms of. death. the flow of time is not that does not i. think uh i think it's i think there's no.

comfort in the face of death for what we. are uh. because we like existing and i think. it's especially true if you if you love. life. and you love what life is. do you think there's a certain sense in. which. the fear of death or the fear of. non-existence maybe fear is not the. right word. is the actual very phenomena that gives. birth to existence like maybe death is. fundamental like this it just feels like.

freaking out oh. this ride ends. is actually like. the. that's. that's the thing that gives birth to. this this whole thing yeah that like. it's constantly. is matter constantly freaking out about. the fact that it's good enough no i. think i think things like to exist i. think they want to exist yeah there's a. there's a desire whatever to exist yeah. and there's a drive to exist and there's. a drive for more things to exist i guess.

um yeah i would like to i like existing. i like i like i like it a lot um. and i don't know it any other way. but see i don't even know if i like. existing i think i really don't like not. existing yes yeah that's you. uh yeah. yeah maybe it's that i. some days i you know i might like. existing less than others but. yes but like i think those are like. surface feelings there is yeah it seems. like there's something fundamental about.

wanting to exist no i think that's right. but i. but i think. to your point that that might go back to. the more fundamental. idea that you know if life is the. physics of existence and maximizing. existence individual organisms of course. want to maximize their existence. and everything you know like wants to. exist but i guess for me the small. comfort is. my existence matters to future existence. speaking of future existence is there. advice you can give to future pockets of. existences.

aka young people. about life you've had uh. you've worn many hats you've taken on. some of the biggest problems in the. universe is there advice you can give to. young people about life about career. about existing. uh maybe not about the last one. um you know a lot of people ask me this. question about like like working on such. hard problems like how can you make a. successful career out of that but i. think for me. it couldn't be otherwise like i have to.

to be fulfilled you have to work on. things you care about and that's always. kind of driven me and that's been. disciplined department. um. uh. and sort of superficial level problem. independent because i'm i. i started at community college actually. and i was taking a physics class and i. learned about. uh you know magnetic monopoles and they. we didn't know if they existed in the. universe and but we could predict them. and we could go look for them and i was. so deeply intrigued by this idea that we. had this mathematical formula to go look.

for things. and then i wanted to become a. theoretical physicist because of that. but that actually wasn't my driving. question i realized my driving question. is. the nature of the correspondence between. our minds and physical reality and what. we are. and. that question's very deep so you can. work across a lot of fields doing that. but i think without that driving. question i never would have been able to. do all the things that i've done it's. really the passion that drives it and i. and usually when when students ask me. these kind of questions i i tell them.

like you have to find something you. really care about working on because if. you don't really care about it a you're. not going to be your best at it. and b it's not going to be worth your. time why would you spend your time. working on something you're not. interested in so find the driving. questions yeah find the driving question. find your your passion i mean i think. passion makes a huge difference in terms. of creativity. talent and potential and also being able. to tolerate all the hard things that. come with any career or life. yeah i've had a bunch of moments in my. life where i've just been captivated by.

some beautiful phenomena and i guess. being rigorous about it and asking what. is the question underlying this. phenomenon phenomena like. robots bring a smile to my face and yeah. that's cool forming a. question of like why the hell is this so. fascinating yeah why is this uh. specifically the human robot. interaction question that's something. beautiful. is brought to life when humans and. robots interact.

understanding that deeply yeah. it's like okay so this is going to be my. life work then i don't know what the. hell it is but that that's what i want. to do. interesting and doing that doing that. for whatever the hell gives you that. kind of feeling i guess is the point. yeah. am i allowed to ask you a question sure. okay um. on that point because i like um at this. colleague that suggests the idea that. like consciousness might be contagious. and so interacting with things you know. isn't it no yeah it's an interesting.

idea right so i'm i'm wondering like. sort of. you know the motivation there is it the. motivation that you want. more of the universe. to appreciate. things the way we do and appreciate. those interactions or is it really more. the enjoyment of the human in those. interactions like is it. is it. i don't do you know what i'm asking yeah. yeah see i think consciousness is. created in the interaction between. yes things yes. so the joy is in the creation of.

consciousness and i see i really. like the idea that. it doesn't. just have to be two humans creating. costumes together it could be. humans and other entities yeah we talked. offline about dogs and other pets and so. on there's a magic i mean i've been. calling it. love is. this beauty of the human experience. that's created and it just feels like. fascinating that you could do that. with a robotic system right and.

right there's something really powerful. at least to me about. engineering systems that allow you to. create some of the magic of the human. experience because then you get to. understand. what it takes at least get inklings of. what it takes to uh. to to create consciousness and i i don't. get this um. you know philosophers get really upset. about this idea that sort of. the illusion of consciousness is. consciousness but.

i really like the idea of engineering. systems that fool you. into thinking they're conscious right. because that's sufficient to create the. magical experience right because it's. the interaction yeah it's the. interaction yeah right and this is the. russian head i wear which is like i. think. i think there's an ocean of loneliness. in the world i think we're deeply lonely. we're not even allowing ourselves to. acknowledge that and i kind of think. that's what love is between romantic.

love and friendship. is two people kind of getting a little. bit. like. like uh alleviating for a brief moment. that loneliness that loneliness but not. but we're not they're it's not the full. aspect of that loneliness like we're. desperately alone we're desperately. afraid of not existing right i have that. kind of sense and i just want to explore. that ocean of loneliness more right. like create a submarine that goes into.

the depth of that loneliness. so creating systems that can truly hear. you right truly listen make the universe. a less lonely place exactly uh let me. ask you about uh the meaning you've. brought up why yeah the physics of why. what do you think is the meaning of our. particular. planets. set of existences and uh the universe in. general. um the meaning of life yes someone once. told me as a physicist i'm not allowed. to ask why questions but i don't believe.

that so. um. i think. i think. what we are is. the creative process in the universe i. think and i for me that's the meaning. um the ability to yeah to create. more possibilities and more things to. exist. how what what is uh. dostoevsky has the saying beauty will. save the the world. what is uh is there a connection between.

creation and beauty. i think so. so is that like. are they is his beauty a correlate of. creation it might be i don't know um i. mean why is it i you know. a lot of people have asked these kind of. questions but like why is it we have. such an emotional response to. intellectual activity or creativity. um and that seems kind of a deep. question to me like it seems very. intrinsic to. what we are so i. i do. have an interest in the questions i ask. because i think they're beautiful and i.

think the universe is beautiful and. um i'm just so deeply fascinated by the. fact that i exist at all. um. and so maybe maybe it's that. you know that that intrinsic feeling of. beauty that's in part driving you know. the physics of creating more things so. they could be deeply related in that way. well i don't think there's a better way. to end it i think this conversation was. beautiful thank you so much for uh. wasting all your valuable time with me.

today i really really appreciated sarah. this is an honor i hope we get a chance. to talk again i hope uh like i mentioned. to you offline we get a chance to talk. with lee you guys have a beautiful um. like intellectual chemistry that's. fascinating to listen to so i'm a huge. fan of both of you and i can't wait to. see what you do next thanks so much. great to be here. thanks for listening to this. conversation with sarah walker and thank. you to athletic greens nut sweet. blinkist and magic spoon.

check them out in the description to. support this podcast. and now let me leave you with some words. from robert frost one of my favorite. poets. in three words i can sum up everything. i've learned about life. it goes on thank you for listening i. hope to see you next time.