Sean Carroll's Mindscape: Science, Society, Philosophy, Culture, Arts, and Ideas - 299 | Michael Wong on Information, Function, and the Origin of Life

Episode Date: December 16, 2024

Living organisms seem exquisitely organized and complex, with features clearly adapted to serving certain functions needed to survive and procreate. Natural selection provides a compelling explanation for why that is so. But is there a bigger picture, a more general framework that explains the origin and evolution of functions and complexity in a world governed by uncaring laws of physics? I talk with planetary scientist and astrobiologist Michael Wong about how we can define what "functions" are and the role they play in the evolution of the universe. Support Mindscape on Patreon. Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/12/16/299-michael-wong-on-information-function-and-the-origin-of-life/ Michael Wong received his Ph.D. in planetary science from Caltech. He is currently a Sagan Postdoctoral Fellow at the Carnegie Institution for Scienceʼs Earth & Planets Laboratory. He is in the process of co-authoring two books: A Missing Law: Evolution, Information, and the Inevitability of Cosmic Complexity with Robert M. Hazen, and a revised edition of Astrobiology: A Multidisciplinary Approach with Jonathan Lunine. Web site Carnegie web page Strange New Worlds podcast Wong et al. (2023), "On the Roles of Function and Selection in Evolving Systems." Wong and Prabhu (2023), "Cells as the First Data Scientists."

At Santa Monica College, a world-class education is affordable. Just $46 a unit with free tuition for eligible first-time California students, plus flexible online and on-campus classes close to home. Summer starts June 22nd, SMC.edu. Hello, everyone. Welcome to the Mindscape Podcast. I'm your host, Sean Carroll. Those of you who have been hanging around here for a while know that in my professional capacity, I go to talks by and read papers by both physicists and

philosophers as well as other kinds of people. And, you know, I love the philosophers very much. They tackle big questions. But sometimes when I'm reading a philosophy paper or going to a philosophy talk, there's a part of my brain that is going, this would be really good if only there were more equations in it. And that's not just physics snobbery in some sense. There's plenty of physics papers that are full of equations and are truly deeply boring and uninteresting. But it's a reflection of the fact that there's one thing, which is to sort of put your finger on an important concept and elucidate how that concept plays a role in blah, blah, whatever you're talking about. It's another thing to really turn that concept into something objective and quantifiable. You know, if you talk about purpose, you know, different aspects of a biological organism serve a certain purpose, for example, okay?

What do you mean, really? And it's not that you can't mean anything, it's that certainly that does mean something, but that making it really quantitative and precise can often be difficult and it can be illuminating. Once you're able to do it, you can actually work with that quantitative definition. And that's what I mean when I say, if only there were more equations, right? The equations are not merely showing off or trying to make things more complicated. They provide tools that you can actually use to learn more about the concepts that you're talking about. And today's guest is going to do something along those lines, at least a little tiny movement in that direction. Michael Wong is an astrobiologist, physics background, but as well as biology and all the different things, planetary science, that you need to be an astrobiologist.

And one of the authors on a recent paper called On the Roles of Function and Selection in Evolving Systems. function and selection are two words you'll see bandied about in biology, whether it's terrestrial biology or astrobiology all the time. But these folks want to make it a wee bit more quantitative. They want to say, okay, what do you really mean by function? And they use equations involving information theory. Very simple equations, but you know, you've got to start somewhere, right? So they define what you mean by a function, by functional information, and then they propose that there is a general tendency, arguably even a law, but I think it falls short of what we would normally call a law, but they're sort of hypothesizing, they're conjecturing that it's a law-like

behavior for this functional information to increase over time in evolving systems. And evolving systems, they mean that phrase literally. It's not just living systems. abiotic systems like minerals and atmospheres and stars can also evolve in some sense. So this will hopefully, if this kind of idea catches on, this is the kind of thing that can lead us to a better quantitative understanding of what life is, how it develops, how it becomes more complicated and more adapted to its environment. As Mike says in the podcast, the thing about the universe is that the environments are extremely complicated. and one reason why you would expect the roles of functions and functional information to increase over time is that organisms need to be able to take advantage of their environment

and able to stave off the bad things about their environments. So hopefully this is exactly the kind of podcast where we're not going to get deeply into deriving equations or anything like that, but we sort of peel back the curtain a little bit on how quantitative measures of these very common notions can be super helpful to scientists in trying to understand things that we don't yet completely understand. So let's go.

Michael Wong, welcome to the Mindscape podcast. Hi, Sean. It's so good to be here. I've been a longtime listener of Mindscape ever since it started coming at in 2018. And I also really look up to you greatly as a science communicator and the way that you effortlessly blend philosophy and physics and have really moved into complex systems. and made some profound contributions to that field as well. So it's a real pleasure to be here. You know, it only looks effortless. There's actually a lot of work. Yeah, yeah, I believe it.

Thank you very much. That's very nice. And it's good to have a fellow podcaster on the show. But what I wanted to start out with was, while peeking at your webpage before we came on, I noticed that you are co-authoring, at least a revised edition of, a textbook on astrobiology,

which just kind of tickles me since the whole field of astrobiology has no known subject matter that we've discovered so far. You know, what does that mean to have a textbook on astrobiology? Oh, it more than tickles me too. In fact, it pains me every single day since, you know, so just as an update in case people are curious because everybody's always asking about this textbook. Mike, when is it coming out? We've finished, we've finished writing the text. The text is set. What's dragging us through the mud right now is trying to get all of the

permissions for the figures, which ended up being a lot more of a slog than I thought. So every single day that passes, since we finalize the text, it gets more and more out of date. And as you said, Sean, astrobiology is this field that isn't really a field yet. It's a pre-paragmatic science. And so it's constantly moving in kind of unexpected directions. So like the launch of JWST, for instance, the James Webb Space Telescope has brought and deepened our view of the universe and exposed us to information about exoplanets, planets that orbit other stars in brand new ways.

Luckily, because the permissions for the figures have taken so long, we were able to include some of that data in the textbook. But it's definitely a process. So astrobiology, a multidisciplinary approach, the first edition was written by Jonathan Lunin, who is now the chief scientist at JPL. He was for a long time professor of astronomy at Cornell. University. And so Jonathan wrote this book in 2005. So it's been nearly 20 years since the first

edition came out. And Jonathan came to Caltech where as a graduate student for one of his sabbaticals. And while he was there, found out that I was teaching as a graduate student, the Caltech astrobiology class and said, oh, Mike, maybe you would like to help me revise the astrobiology textbook. And so I signed on to that. And it's been a lot of fun writing it and less fun trying to wrangle all the figure permissions. These are the things they don't tell you when you say I want to be a book author. You know, there's a lot of those things. Eventually I just broke down and, you know, make almost all my figures myself. We had enormous trouble just getting to the legal department at my publisher to allow us to use a public domain image of LIGO because they weren't sure. They couldn't convince themselves, so I'm very sympathetic. Yeah. So what is the table of contents for a textbook on astrobiology look like?

Oh, that's a great question. Okay, so astrobiology, the multidisciplinary approach, goes through some of the foundations that you need to understand for astrobiology. So the first few chapters are like fundamental physics, chemistry, and biology. And then we start dealing with the origins of life. Well, first the origins of planets, because life is a planetary phenomenon. And then the origins of life, the evolution of life, the search for habitable environments in the solar system and beyond. And for that, we take a little digression to exploring the diversity of life on Earth, the extremophiles,

that inhabit all kinds of environments that we as humans find extreme, but might be representative of the kinds of planetary conditions elsewhere in the solar system, perhaps on Mars or some of the icy satellites like Europa and Enceladus, and they sort of help us broaden our scope for what habitable environments might look like and understand what to expect adaptations might be for organisms that evolved and say the frigid ocean waters of Europa. And then we talk about exoplanets and this revolution of now we have nearly 6,000, you know, strange new worlds out there, some of which might be habitable for life as we know it,

and how would we go about assessing their habitability and then their inhabitants? if there's anybody living there. And then we speculate wildly about, you know, the future of human civilization and the search for extraterrestrial intelligence. Well, you've earned it by the end of writing a book like that, right? You're allowed to speculate wildly, I think. But, you know, you mentioned the origin of life, and this is something that is one of your technical research areas.

So maybe since you're the textbook author, maybe I can ask you, because I ask all my Origin of Life guests, this question, like, what is your feeling for the current? state of the art, you know, within the field. I know there's different schools of thought about how life began. Is there like a dominant one? Are we homing in on an answer? Or is it still needing big ideas to come and clean things up? I think it's still needing a lot of big ideas. There are a few, I guess, dominant camps with regard to the origins of life. People speak about this divide between, say, metabolism first origin of life. and genetics first or information first origins of life.

But of course, in reality, you need both. But I think the reason why it's driven such a hard wedge in the field is because each paradigm or expectation for what the first living system looked like results in different prebiotic environments that are favored. So the folks that favor an RNA first, genetics first origin of life, are looking for environments that people think are suitable for the abiotic creation of a molecule like RNA. And that tends to be superficial ponds under an atmosphere

that can deliver organic molecules to the surface that undergo wet, dry cycles that allow certain kinds of complex chemistry to take place and form long polymers of RNA. The metabolism for a scenario tends to lead people down into the depths of the ocean where, you know, these hydrothermal vents exist. And the idea behind metabolism first is you want to think, think about the thermodynamics of life and the fact that you need a free energy gradient to

tap into in order to get some kind of self-sustaining dynamic system. And at these hydrothermal systems, you have such gradients in the form of a redox gradient, so a chemical gradient between the effluence of these hydrothermal systems and the surrounding seawater, as well as a natural pH gradient or a natural proton motive force between the alkaline solution that's bubbling out of these vents and the acidic ocean water. And it turns out that life to this day harnesses both redox and proton gradients in its metabolism. And so if you want to think about where might be a primordial geochemical environment where those things were abundant and easily accessible, you look at submarine alkaline hydrothermal vents. Should it worry us that the obvious place to look for

the ingredients in a metabolism first approach are not the same as the obvious places to look for the ingredients of information first approach? Worryous in what sense, Sean? It's hard enough to make life go at all, but if RNA comes to live on the surface and the engine, the metabolism that makes things go, is being formed deep beneath the ocean that makes it even harder for them to team up. Yes, yes, that's, okay, I see what you're getting at. Okay, so I think that the answer to that is that people are perhaps not as worried as they should be or bothered as they should be because in every kind of origin of life scenario, and I deeply apologize if I am going to insult any of the audience members who actually work on the origin of life. In my opinion, a lot of these traditional

origin of life scenarios have a good deal of magic sprinkled into them in the sense that if you subscribe to the RNA world first scenario, you're going to find a nice tide pool where you can generate a precursor to RNA, and then you say, okay, Darwinian evolution is just going to take over and you will somehow build that metabolic engine that you require for a true living system. On the other hand, if you're thinking about hydrothermal systems, then the magic element is that somehow, far down the road, RNA is going to be one of the outputs of this metabolic engine that has formed at the hydrothermal vents. So I think there's a lot of like dot, dot, dots.

Miracle occurs, dot, dot, dot, you know, in each of these scenarios. And that's where I think this big question, the big questions that you were alluding to at the beginning of the podcast come into play. It's like, so what actually links these two things up? And maybe not even in a spatial sense in that, okay, maybe you need to get a warm pond on the surface to talk to a hydrothermal event. But, you know, what principles behind the emergence of life might be applicable at, say, both kinds of geochemical systems. And one thing that I like to point out to people thinking about

the origin of life is like, you know, they could both be right. There's no reason why they couldn't both be right. And they could also both be wrong. Maybe we just haven't thought of the right geochemical system yet. And so I think that we have to be very open-minded when it comes to the origin of life still. That makes perfect sense. I like the picture that obviously this is an exciting field and we're very getting more data that is relevant to the questions we're asking here. but there's still huge unanswered questions that are very foundational. That's a good area to go in for a young person interested in exciting science. So you recently organized this workshop that I went to the Wise Workshop,

and it dealt with some of these issues. And in particular, I'm fascinated by the give and take between getting really nitty-gritty, looking at certain chemical reactions and certain environments and certain planets and so forth, versus stepping back and thinking about grand abstract principles that say, you know, complexity or information or organization or something like that should come to be. How do you think about the balance between those two things? And feel free to like say what the most interesting things that you discovered or talked about at that workshop were. Yeah.

So the workshop on information selection and evolution or wise was a really fascinating kind of experiment for me in bringing together. people from all sorts of different fields, physics, philosophy, biology, chemistry, even some of the social sciences. And just seeing what happens when you put people in the same room over an exciting topic and see what ideas bubble forth. And I think that, you know, the success of such a workshop may not be able to be assessed until, you know, many years down the road when somebody tells me at a conference, oh, Mike, you know, the reason why this particular

scientific project happened was because I had a very confusing conversation five years ago at the Wise Workshop. But I think for me, it was just a really fun experience to talk to folks like yourself who've been thinking very deeply, but maybe in different ways or using different language about the same kinds of fundamental processes, information, selection, and evolution. And of course, their relationship to very pressing, you know, finer-grained scientific questions like how do you get the emergence of life on a probiotic planet? It might have been the, I'm not sure about this, but it might have been the largest collection of former Minescape podcast guests that have been physically located in the same place.

Neil Schubin was there, Chris Adami, Janinez, Emile, Stephen Wolfram, Barry Lower, Kate Jeffrey, so that was great. I'm glad that we have you here. So do you think it is, I mean, I think I know the answer to this, but do you think it is useful to try to think about general principles in this context? Like obviously, it's very useful to go to Europa or to Enceladus or whatever, and it's also very useful to take spectra of exoplanets. Can we think our way into understanding reasons why life might have come to be as a process?

Yeah, yeah, I think it is very useful to think about general principles behind complexification. and life. This is all part of, you know, our quest to try to understand what the phenomenon of life really is. And right now with a single example of life here on Earth, it's hard to do that kind of generalization from our so-called n-equals one. Despite the amazing diversity of life, this is almost like a beautiful contradiction here on Earth that, you know, we've got all these diverse life forms, you know, from single-celled bacteria in your gut to the vast forests and jungles. But everybody on Earth is related to one another. And as my friend and colleague, Professor Mohamed Nour,

who's a geneticist, likes to say, no matter what you ate for lunch today, even if it was just a salad, you ate a relative, right? So we're all related. We all share some kind of universal biochemistry. And who's to say that life on Europa or Enceladus or Titan or some distant exoplanet might have had a different, you know, contingent early evolution that led them down

different path that, you know, just because something we see here on Earth is universal to all life on Earth doesn't mean that it will be universal across the cosmos. And so I think there is value to trying to, you know, go to these other worlds. And I don't think we'll really know what life truly is until we've found many more examples of it and are able to sort of like say, oh, okay, this is the true diversity of life elsewhere in the universe. But it's also useful in that search to try to think about what might be the universal properties of life in the universe to help us inform our search and widen it such that we don't accidentally miss something hiding in plain sight. And so Stuart Bartlett, for instance, was a previous Minescape guest, and you talked about our conceptual paper of

Life of the Why, which was our attempts to sort of generalize away from like, oh, maybe instead of saying life, does Darwinian evolution specifically, it is just simply capable of doing information processing and learning about its environment, you know, because life on another world, perhaps, you know, does evolution differently from the way that life here on Earth does. It could evolve remarkably, perhaps. And so, you know, that was our attempt to take a more process-based, generalized approach to what life could be in the universe. Well, that's a great point because, you know, we, none of us here are, I presume, vitalists, you know, we don't think that there's magic that animates life or anything like that. Living things are continuous with non-living things. So it does make

sense to think about the most general principles that would apply to both. And I'm interested in this paper that you recently were an author on called On the Roles of Function and Selection in Evolving Systems. And there's a long list of authors on this paper, including philosophers and biologists and things like that. I mean, maybe give the listeners a little bit of background as to how a paper like that even comes to be. Wow. What a good question. So yeah, I'd say roughly three years ago. So, yeah, fall of 2021, I joined Carnegie where I currently work at Carnegie Institution for Science, specifically the Earth and Planets Laboratory in Washington, D.C., as a postdoctoral fellow. And my advisor, Bob Hazen and I went out to lunch, our very first meeting, you know, as mentor,

and we started talking about, you know, the questions that interested us the most. And I joined Carnegie as an astrobiologist. I'm really interested in how to go look for life in the universe, but I'm very aware that the, that we cannot be too constrained to just looking for life as we know it, as we know it here on Earth. We need to take, you know, as I said before, that broader kind of scope to make sure that we don't miss anything. So what are sort of those universal aspects of life?

And Bob and I both, you know, talked about information. information as sort of that thing that might be the right sort of Goldilocks level of abstraction, right? So we want to abstract away from the specifics of life on Earth, but we don't want to abstract too far that like literally everything might accidentally be categorized as life. Exactly. We're looking for that Goldilocks level. And so we talked about information. We talked about evolution. And we thought, you know, maybe there is something broader about evolution that can be applied to not just living systems, but non-living systems as well. And we can see aspects of

evolution, complexification, diversification, patterning, you know, as a sort of spectrum rather than, okay, you know, biological evolution is the only form of evolution in the universe. And so Bob has been thinking about this for many, many decades and has previously written about three aspects of any complex evolving system. So for Bob, the attributes of any complex evolving system. Number one, they have to be composed of many different interacting components. Two, there exist mechanisms to generate many different configurations of those components. And three, there is selection for function that essentially prunes or winnows the possibility

space to a few select configurations. And when you explain that to me, I said, okay, I get number one, I get number two, I don't get number three. What is what a selection for function actually mean? And so we decided to put together a reading group here at Carnegie, pulled together interdisciplinary scientists. So Jim Cleaves joined our group. He's in Origins of Life, Organic Chemist.

We have Anirud Prabhu, who's a data scientist and informatician, who brought a great deal of wealth of information on, well, expertise on information. And then we thought, okay, it would be good to have a theoretical physicist on board. So I reached out to my friend Stuart. And at a certain point, we sort of hit a wall where we're like, I think we're getting close to something profound, but we don't actually understand enough about what is going on in terms of like what a natural law or a principle or some kind of theory. So we started reading some philosophy papers and Bob reached out to his colleague, Professor Carol Cleland at CU Boulder, who reached out to her colleague, Professor Heather Demarest, Also at CU Boulder, those two are philosophers of science. Carol has written plenty of work on the philosophy of astrobiology and definitions versus

theories of life. And Heather is an expert in the philosophy of natural law and time and physics. And we all got together and we're just like, okay, maybe we should just continue having meetings over Zoom every single week. And eventually out of all that came this paper, which hypothesizes that there might be some kind of law-like description of complex evolving systems that expands evolutionary theory beyond just Orwinian evolution, and that you can see evolutionary processes at play throughout isotopic evolution, mineralogical evolution, planetary evolution, biological evolution,

potentially even in symbolic systems like language and then technology and culture, etc. Well, I really appreciate that that was great, because I think that to a lot of people who don't participate in scientific research on day-to-day level, the whole process by which a paper gets written can sometimes seem like a little magical or at least opaque. And that's one of the ways. Like, as you know, there's all sorts of different ways that conversations or ideas can eventually grow into papers. Yeah, yeah. It's really fun to be able to just, you know, I feel so lucky to be able to have the time and the space as a postdoc to just sort of experiment and to do science the way that I want to do science and to explore the questions that really pull at me.

And I'm just so grateful to all these colleagues for signing on board and chasing this wild idea for the past couple of years and putting together a workshop like Wise and everything like that. It's just been a blast. I could not have predicted this three years ago that I would be thinking in these areas. And it's just been so fun. So I do want to get to the idea in your paper that we can talk about certain aspects that are common to. life and non-life. But first, let me kind of push back on that idea. I mean, there's something special about life, right? I mean, there's something in the existence of DNA that gets passed on from generation to generation that, I mean, the way that I think about it, and hopefully you'll

correct me or put me on the right track, is that a living thing learns or has the capacity to leverage information in a way that non-living things don't quite, right? I mean, DNA is a code. It's a crystal, like in some sense, like Schrodinger pointed out, but because it can be infinitely malleable, it really has capacities that otherwise aren't there. And I harken back to a different paper that you wrote, sells as the first data scientists, which I love that title of it. I mean, so maybe talk a little bit about this informational aspect of life and Am I exaggerating to think that that's like really super different than everything that goes on in the non-living regime? No, I think you put your thumb right on it, Sean.

It's that in life there is this like full circle, this full cycle of the way that information is acquired from the environment and then utilized for the persistence of that dynamic system. You know, there are many different ways that a dynamic system fueled by the dissipation of free energy can continue to persist. One is through autocatalysis, so some positive feedback loop that maybe spreads that system farther and farther. So you can think of wildfire, for instance, spreading through a forest. You could have homeostatic feedbacks that are able to allow that system to resist certain fluctuations in the environment. So negative feedback loops could be really important. And then the idea that a system can do this kind of information processing, where the information that is encoded in it from interactions with the environment actually then go and play a

causally interesting role in its continued viability. And I think that's what separates life from non-living systems, is that it does all three of those things in addition to the dissipation of free energy. And so, you know, minerals, for instance, are amazing. They complexify over time and their chemical structures do record information about the environment in which they formed, but that information doesn't then feed back into that mineral's persistence in the way that information does in biological systems. So I think that's sort of the big distinction there. And so, yes, there is something special about the way that life evolves versus everything else, but I think that you can still cast evolutionary theory in a wider scope to involve, you know,

traditionally thought of as non-living things. Good. I think that that makes a lot of sense. So in that vein, let me run by you an epiphany that I had or think I had at your meeting at the Wise Workshop, which is the following. If I have a box of gas, I'm thinking like a physicist here, I can't help it, right? So I have a box of gas with a bunch of atoms in it. And it's hot enough that the atoms don't actually recombine to make molecules. Okay, so they're individual atoms. the space of possible configurations of those atoms is very, very large. Like every atom can be anywhere, right? And, you know, that's a very large number. But they sort of maintain a certain level of simplicity there because they're just little billiard balls bumping into each other. Whereas if I lower the temperature and now atoms can come together and make molecules,

maybe complex hydrocarbons DNA or whatever, then technically speaking, the space of possibilities has decreased, right? Because if I'm just looking at the atoms themselves, I'm not looking at the photons or whatever, they're the environment. Because atoms are sticking together, there's fewer places they can be. But it's a more interesting space of possibilities. Like the sort of, I am tempted to use the word functional because that's the word that you're going to emphasize in your paper, but the sort of information-bearing space of possibilities has increased in some sense because there are different combinations into which the atoms can fall and start making

interesting kind of structures. I don't know how to formalize that, but is this little epiphany just like, you know, standard stuff in origin of life, or am I making up nonsense? No, I think that's a really interesting example. So, yeah, let's play around in this box of gas of yours, a box of atoms. So yeah, I think in our framework what what we would say is going on is that when the temperature is too high and the atoms cannot bind into molecules, you yeah, the the possibility space is just defined by the position and the moment of the particles in the box, right? But then when

you turn down the temperature, you allow there to be different kinds of configurations and in these molecular forms, and all of a sudden you have maybe leapt into a possibility space that is potentially defined better by different language in your poetic, naturalistic sense. Is that, right? Right. So, you know, you can always define and, you know, describe this box of particles at the level of the atoms, just bouncing around the box. But when you are able to make these, you know, fundamentally new structures, which are molecules, you may want to shift yourself into a completely different possibility space, maybe a different state space, to describe the interactions of those molecules. And in, you know, hopefully, if you're interested

in the emergence of life, some of those interactions of those molecules will generate the kinds of functions that we associate with life, maybe an autocatalytic reaction. action will occur that simply cannot occur if you're talking about individual atoms bouncing around in a very hot plasma. Yeah, of course, this example is not entirely random. In some sense, the universe is a box of gas that cools over time. So it is very relevant. Okay, so, but in your paper, we're going to talk about functional information and things

like that. but part of the aspiration is to talk about evolution in the sort of lowercase-e sense, like the change over time of different systems. So not strictly speaking only Darwinian evolution, not natural selection, but even like you say, the evolution of chemical systems or mineralogical systems or things like that. So talk about the aspiration to have a unified theory of evolution that is both biological and non-biological evolution. Right. I think so for us, an evolving system is a collective phenomenon of many interacting components that displays some kind of temporal increase in diversity or distribution or patterned behavior. And the aspiration here is that we look around at our cosmos and we see this kind of time asymmetric behavior in all kinds of things, including life and technology and things like that, but also. So in non-living things, in the precursors to life, the generation of new isotopes and new minerals, for instance, that were essential for leading to life.

And so if we are able to understand complexity, the generation of complexity at a more basic level, perhaps will also be led to some of the principles that could lead to the emergence of life. Well, the word that appears very often in your paper, one that I'll confess I'm not yet completely comfortable with myself, is function, right? It's different things that arise over the course of evolution, be it biological or non-biological, serve different functions. And part of your goal is to quantify what that means. So let me just ask the background question. What is a function, and is it supposed to be quantifiable? Great question. Yeah, so a function is for us, basically any process that might emerge in a system that has some kind of causal efficacy over its continued persistence or viability.

And so we spoke about before how all dynamic systems are driven by thermodynamic dissipation, but then certain other feedbacks might arise inside of them. And so, you know, you might have, again, autocatalysis, homeostasis, and information processes. And these are what we call the core functions in that they directly contribute to dynamic systems, continued persistence. I think much in the way that Adi Pross on your podcast a few episodes ago talked about dynamic kinetic stability. And a lot of our work was inspired by reading some of Adi's papers. And so, you know, once you have those core functions online in a system, then I think what you really have, if you have all of them, is a living system. and it doesn't necessarily need to look like life as we know it on earth. But life also generates a lot of novelty.

It discovers new functions, new ways of interacting with its environment and potentially harnessing new free energy resources or updating its knowledge about the environment in new and interesting ways. Darwinian evolution was probably one of the first ways in which living systems here on Earth were able to, you know, assimilate information correlations with its environment and then better itself for its survival. But, you know, we also emerge the ability to, or evolve the ability to do, you know, have sight and think and, you know, cognate about things. And you could think of that as, you know, a faster updating of

information about one's environment too. And so we talk about how novelty generation can generate all sorts of ancillary functions that through their interactions in a sort of nested way with the core functions continue the dynamic persistence of the system that they're in. I guess, though, what I'm still unclear about is whether or not we're using our human-tinted eyeballs to sort of see functions where we want to see them, rather than having a purely objective description. And maybe this is just the looseness of the natural language term function, right? Like, is a riverbed serving the function of delivering the water to the ocean, or does that not count under your definition? Good question. Yeah. So I think that what is

essential is to try to tie the function that you're talking about back to some measure of persistence or viability. And so when I give talks about this, I often ask the question. So is, you know, what functions does the universe care about? Does this is slimyness being slimy like a function that should matter? Right. And it's very contextual, right? It's very contextual because most of the time being slimy doesn't matter. But if you're a snail, you know, generating mucus so that you can move this ancillary function of movement so that you can go and get your next meal does become very relevant for your ongoing persistence.

So one of the things that we have to wrestle with. here in this framework that may be right or maybe wrong is the contextual nature of defining functions and whether or not you can be contextual but also objective about this. And can you, can you by drawing connections to the persistence of systems do that objectively? But persistence, that's good because that's what you're sort of focusing on. And AdiPros also does point to that. And you almost want to use the word survival, but that makes it sound biological. but persistence is a feature that both biological and non-biological systems can have, I guess. And so, I mean, maybe give us some more microscopic examples of functions and what they might be.

So people aren't just thinking about, you know, the function of my coffee cup is to bring me coffee or something like that. At the level of biochemistry, what are we thinking about when we're talking about functions? Sure. Okay. So I think one early function, that might have emerged in some prebiotic environment, if again we go to the origin of life, is these autocatalytic sets. So imagine, you know, molecule A creates molecule B, molecule B creates molecule C,

and then molecule C, then goes and creates molecule A again. And there's this cycle, right? So, you know, autocatalysis, and Stuart Kaufman, who was also at the Wise meeting, was one of the pioneers of this field of autocatalytic networks at the origin of life. Once you have that kind of dynamic feedback, you could say that any one of those particular molecules serves a functional role in completing that autocatalytic cycle. And they might be selected, you know, the whole cycle is selected by the environment for its dynamic persistence.

And once you have that kind of selection for dynamic persistence, the abundances of molecules in your environment changes from the pure abundances that they would have had if they were just selected for their static persistence, right? So maybe molecule B is very, very short-lived, but it's highly abundant in this system that has been selected for dynamic persistence because it is constantly being recreated by molecule so that it can complete the cycle and it makes more of itself. And I feel like this might help us understand how to look for life elsewhere in the universe by looking at the district of different organic molecules and noticing in a very high dimensional sense taking the abundance of each organic molecule as sort of like an axis that you're measuring the system on Whether or not the distribution of organic molecules in some interplanetary sample looks very different from the way that the distribution of organic molecules in

a non-living just purely geological sample might look like and if so, then you might be looking at, you know, some interesting kind of chemistry that was selected for something other than the static persistence of those organic molecules. So you're looking at the evidence of selection for function. So that's actually very helpful. So is it safe or is it fair to say that specifically the kinds of functions we have in mind are those that if you removed them, the system would not be able to persist as well? That's right. Yes. Okay, good. So it's like, you don't want to speak to you teleologically, right? So words like purpose and things like that are a little worrisome.

But if you know what you're talking about, maybe they're okay. So these are functions that serve the purpose in that context of helping this system persist. That's right. Yeah, yeah. And, you know, we've had so many debates over the years about whether or not to use words like purpose. And it's easy to just throw them out there. And I am absolutely guilty of doing so a lot. And for me, I guess I wonder if purpose is something that is, that you can talk about in this contextual emergent sense. I think it is.

Absolutely. Okay. So good. With that in mind, are there functions in that exact sense, or do functions in that sense predate the existence of genetics, of the information role? Is this like a third contender for the origin of life? It's not metabolism first or replication first. It's functions first. Oh, wow.

I'd never thought to characterize it quite like that, mainly because I don't want to have to get into another battle in the origins of life fields with literally everybody else. But I think that what you're looking at here is maybe a principle or a way of conceptualizing of the origin of life that is a little bit agnostic to, the specifics of the different camps in the origins of life field. So the genetics first folks are certainly thinking about a function that the RNA molecule is serving, namely self-replication,

right? So that's sort of like an autocatalysis. And so it, so, and the same thing can be said of the first metabolic network at a hydrothermal system as well. And so I think that, you know, one dream of mind would be to help contribute to some kind of, you know, principles of life or theory of life that would be able to help us understand the abstract necessities or requirements for the emergence of life that then we can go and test in these various, in these various systems. And I think that a lot of origins of life scenarios do try to achieve these types of things just in, you know, with a lot more constraints on the particular chemistry that they're worried about. And then what you, that's extremely helpful.

I understand a lot better what is going on with the function talk. And then you make a point in your paper that if what you want to do is persist and these functions are helping you persist, there's a bit of a pressure to invent new functions to help you persist even better. And then you can kind of see the beginning of what we think of as evolution without using any of the usual Darwinian language. Yeah, exactly. And so the language that we use in our paper is novelty generation, the discovery of new functions that might further promote persistence. And novelty generation might itself be selected for, especially when you have an environment that is very complex, not just spatially heterogeneous, but temporarily changing as well. And the environment of the early Earth and the modern Earth for sure is one such kind of genial environment. And so that would incentivize systems to perform some degree of novelty generation because you might be sitting in a very functional configuration right now. But if the environment shifts and that that function landscape changes tomorrow you might be at a very less functional configuration.

So you need to continue to explore parameter space to maintain your viability and persistence. Okay. So now we've reached the point in the podcast where I say, where are the equivalent, equations here. Can we, you know, and that's, we don't actually want to discuss specific equations, maybe, but how quantitative can we be about turning these words into scientific concepts? Like, is there a measure of functionalness? Yeah, so the metric that we propose is called functional information. It's actually not invented by us.

It was first introduced by Jack Shostack in 2003, and then was elaborated on by Bob Hazen and colleagues in 2007. And so we appeal to functional information as a possible metric for measuring the increase of functionality of these complex evolving systems. And real briefly, what the functional information is. It's basically a measure of the fraction of configurations of a system that can perform or achieve a specific function.

And so it's, you know, the math is, it's the negative log base two of the fraction of configuration, so it's measured in units of bits, and essentially the fewer number of configurations of a system that can perform that function, the higher the functional information is of that system. So it's relatively simplistic, but we've been able to test it in a few cases,

namely the mineralogical evolution of planet Earth, as well as it exhibits increasing functional information in, say, artificial life systems, and like the Avita system as well. And so functional information is difficult to quantify for many complex evolving systems because you need to know the entire, you know, sort of like combinatorial parameter space,

and you also need to know the functionality of all the different configurations. And so for certain systems, we're able to do this. So in mineralogy, there are only a certain number of configurations that are possible. But if you want to apply this to biological systems, there, you know, it's a much more complex problem because the combinatorics explode wildly.

But, you know, Bob likes to point out that, you know, we can't solve exactly the gravitational potential of the solar system, right? Very true. Yeah, but we can still send spacecraft to Jupiter, right? And so there might be certain shortcuts that we can use, yet to be discreet, or invented in the functional information framework for us to be able to assess the functional information of wildly complex systems like biology and society. So maybe you can elaborate a little bit more on why the thing that matters is the fraction

of configurations that achieve a certain degree of function. I mean, very loosely, we're imagining systems that have all sorts of different configurations they can be in and they want to have some function achieved. shouldn't I just care about the ability to have one configuration that achieves the function? Why do I care about how many different configurations or the fraction of configurations that achieves that function? So if you have just one configuration that can achieve that function and only one, then your functional information is maximized, right? But it's often the case that you can have slight variations in, you know, so if we take an example, you know, say like a, you know, a protein or a strand of genetic material, you know, you might be able to tinker around

with it to some degree and still achieve the same outcome, but eventually, you know, you make too many mutations or, you know, you change the folding of the protein. It's usually a disaster at that point. And so you might imagine this function landscape that looks almost like a delta function, but there is a little bit of width to it. And so, you know, there is a certain region of that functional parameter space of that configuration space that is functional and so you know the idea is that as evolving systems continue to evolve over time you know the parameter space will increase greatly so you have this combinatorial um explosion or this expansion of the configuration space but as long as you're selecting for for these persistence enhancing functions um if if the

selection pressures continue to increase, then the functional, the sub volume of that functional hyperspace will go down. And so the functional information of the system will go up. Okay. I will just apologize. I completely got it backwards because I forgotten that you've defined the functional information as minus the log of the fraction of configurations that do this thing. So yes, I see. So the functional information is highest. when there's only some very, very delicately arranged, maybe not delicately, but specifically arranged configurations that do the job. And basically then you're characterizing how awesome it is that this job can be done

because most configurations wouldn't perform it. That's right. That's right. And you would like to say that there is a law of increasing functional information. So tell us about that. Yeah, so that's our proposal that there is a law of increasing functional information. increasing functional information that applies to, again, all kinds of disparate physical chemical systems, including but not limited to biology.

And one thing that obviously still needs to occur if it is truly going to be accepted by the scientific community as a law of nature is to test it and test it incessantly and in a wide variety of systems. And so as I mentioned before, we've been able to quantify the functional information over time of a few number of select systems,

but we're always looking for new systems to use as case studies to try to understand whether or not this is actually true. For something like the Second Law of Thermodynamics, or even Einstein's equation in general relativity, I can be axiomatic about it, right? I can set up some assumptions and I can derive a law. Can you do that with increasing functional information?

Is there some sort of background assumptions under which this is a theorem? I think so it is a bounded law in that it, you know, we say that it applies to systems that have those three attributes, you know, lots of diverse components, mechanisms of generating different configurations of those components, and then selection for these persistent enhancing functions. But I don't think you can, you know, necessarily derive this from first principles.

This is more of a macroscopic law that emerges once, you have a large collection of interacting entities. I don't know if that answers your question. Well, I mean, the second law of thermodynamics is also that, or even maybe natural selection is also that, but we can maybe still derive them. I mean, perhaps what we're saying here is that this is homework for the very ambitious young audience members

who want to actually make a mathematical derivation of this purported law. Sounds good. And so tell me a little bit more of the details about the examples that you mentioned. So you have this proposed law of increasing functional information. And if you have, well, can you define all of the quantities in your law objectively and quantitatively enough to actually look at experiments, to look at data and plot the functional information and watch it go up? Yeah, so really, really good question. So the first thing you have to do is identify the system of interest and then identify the function upon which you want to make the quantitative statement about the functional information.

And so in certain, you know, limited case studies, like for instance RNA aptamer evolution, you can see this occurring. So an RNA aptamer is basically a short strand of RNA that, you know, binds to a very specific. target molecule. And you can evolve these things on the lab bench and, you know, select for the ones that can bind the best and then propagate them to the next tube and then, you know, continue to do, you know, this experiment. And eventually, you know, you get this evolution of a very great, you know, great RNA optomer. And so, you know, you see the functional information increased there. In mineralogical systems, when you assess the functional information of minerals with respect to function of their static persistence, again, because minerals don't do very much, but just either

stick around or erode away. You can see the functional information of minerals over deep time from the first minerals that were created in the atmospheres of stars, through the minerals that were created in protoplanetary disks and in planetesimals, through the minerals that were part of the Hadean crust on the earth, and the minerals that were generated then through plate tectonics, and even the minerals that are here on Earth generated from life, you know, a third of Earth's mineralogical diversity is biologically mediated. The functional information of minerals has gone up as well. Okay, cool.

And I do want to give you a chance to talk about the other example you talk about in the paper, which is the atmosphere of Titan. Oh, yes, yes. Okay, great. So this was a contribution from Jonathan Luny. who is an expert on Titan and has studied this fascinating body for many years. So for audience members who aren't super familiar with Titan, it is the largest moon of Saturn and the only moon in the solar system with a thick atmosphere.

Its atmosphere is mostly made up of nitrogen, same as our atmosphere here on Earth. But the secondary component in Titan's atmosphere is methane. So it's like 3 to 5% methane, depending on where you look in the atmosphere. And there's this big conundrum on this. Titan of why do we even see methane on Titan at all? Because it is irreversibly converted to higher order hydrocarbons through photochemistry, the way that sunlight interacts with methane, breaks it apart, and then the bits and pieces gather to create these tholin-like particles, these aerosols

that then just settle out onto the surface. And the chemical timescale for this process is roughly 30 million years, so vastly shorter than the 4.5 billion years that Titan has been around. So why is there even methane there? And there's an intriguing hypothesis that perhaps you can reconstitute methane in the organic, through the organic mineralogy on Titan's surface, basically taking hydrogen from the atmosphere and combining some of the carbon in the surface and then spitting out methane back into the atmosphere. There have also been very speculative astrobiological theories about methanogenic lifeforms, in Titan's surface, but we need not invoke those. Perhaps it's just a purely abiotic process.

And if so, then you might basically see the existence of Titan's current atmospheric state full of methane that is being irreversibly converted into higher order hydrocarbons, which then settle out into the surface, create a very diverse organic mineralogy on Titan, which then interacts with the atmosphere to regenerate methane as one of these autocatalytic cycles. One of these, and so the whole Titan atmospheric state, along with the organic mineralogy of its surface, could be thought of as a system that has been selected for its dynamic persistence.

I wonder if you can do that for stars. There are cycles in fusion cycles in stars. I wonder if that counts in your definition. Perhaps I'm not an expert in the fusion cycles of stars, but I can definitely see how that might be the case. I mean, I guess to those of us like myself who are not working chemists, it's easy to think about sort of single shot one-way chemical reactions, right? You know, I burn a piece of wood and it converts. But there are a lot of cyclic kind of things in chemistry where there's some input that you get, but then there's some certain ingredients that just kind of go around in the

cycle and then there's also some output there, right? Exactly. Yeah. And so those, are the kinds of systems that if there is a selection pressure for resistance might constitute, you know, and the more complex that system is, very high functional information system. Good. And you just use the word complex, which is good, because my next question was going to be, how does this idea relate to complexity in general or to other versions of thinking about the evolution of complexity over time? Yeah, great question. So as you've discussed numerous times on this podcast, Complexity is this word that, you know, everybody has their own little definition for. It's sort of ill-defined.

And so we're trying to maybe, you know, move away from the idea of complexity in a comagora of complexity sense as sort of the thing that is increasing over time, but rather it's this functional information, right? And it might be that something simpler, a simpler system, functions better, persists better than something that is wildly complex. And so maybe it is not this sort of like, you know, traditional complexity metric that is what we should be thinking about in the evolution of these systems,

but rather how they interact with one another and co-create each other's persistence. If there is this growth, law-like growth of functional information, how do you reconcile that with the second law of thermodynamics, which says that entropy is just going up? Entropy is just going up. And so we're not saying the second law is in any way wrong or whatsoever. The second law is there.

And what we're trying to do, I think, is just layer on principles that can help us explain the rise of complex functional systems in a universe that is driven fundamentally by the second law of thermodynamics. You can imagine a universe in which the, you know, just like our universe, you start from a very low entropy state and you end up at heat death that doesn't produce any of these complex systems. So what is there that we need to talk about in addition to the second law to explain everything that we see around us? And eventually, though, I mean, this is one of the worries about thinking of it as a law, right? If you equilibrate, if you wait long enough and reach the heat depth of the universe, I presume the functional information will once again be low. Yes, yes. And just like your coffee cup example, where, you know, the complexity of the coffee cup goes up

and then it eventually goes back down, when you mix the milk into the coffee and, you know, you get the tendrils and then it eventually becomes uniform, same thing with functional information. We would expect the functional information of the systems in the, of the, of the, of systems in the universe to peak at some point and then return down. Again, the functional information framework only applies to systems that have large number of components, ways of generating many different configurations of those components and selection for function. And I think it's that second criterion that is no longer satisfied deep into the universe's history. Right. And so really number two

is all about free energy gradients because to create these complex dynamic systems, you need to be able to tap into some low entropy source, and eventually that's just going to run out. And if this applies to sort of pre-biological things, like minerals or atmospheres and things like that, does it also apply to what we might call post-biological things, societies and cities and technologies? Yeah, yeah. We're looking for ways of assessing the functional information of certain post-biological things. You know, I've had really interesting conversations and discussions with and about systems ranging from tumorogenesis to folks at the Harvard Business School who read our paper and were interested in it to people who study neuroscience and the functional information that might be on display in our very own brands.

And so all of these things are very nascent and we haven't really, you know, published anything on them yet. Yeah. It's just been wild to have these kinds of discussions with people way outside my own field, and I can't wait to see where they lead. Yeah, cool. Okay. So with that in mind, with the wild discussions idea in mind, and since we're at the nearing the end of the podcast, I notice you also have a paper out in the last few years about the Fermi paradox. And what was the phrase? Burnout was used. Yeah, yeah. So this is, okay, yeah, this is the time of the podcast where we can let down our hair, right? Yeah, we've made it there. Okay, yeah. So that paper was very much inspired by some of the work of Jeffrey West, a former Minescape guest, who talked about these sort of how cities as as social reactors kind of are super linear in their, in scaling, especially their energy consumption. And that cities tend to go on these trajectories towards some kind of singularity where they will utilize

infinite amount of energy in a finite amount of time. And how we skirt our way past those terrible singularities by having innovations. But these innovations must come at a faster and faster and faster pace. And so the speculative paper that we wrote about, we wrote was about the idea that once you have a globe that is connected in a city-like way, basically people being able to communicate with each other, doing the social reactor at scale

through things like what we're doing right now, having podcasts that we can exchange information, even though we're not co-located with one another, that the entire planetary civilization might then be headed towards some kind of singularity. And in principle, you can skirt those singularities over and over and over again, but eventually that time scale of innovation becomes so small that some kind of internal or external fluctuation will knock you off and you will then enter what we call a burnout, which is that you use too much energy and you're no longer able to be viable.

And so the interesting thing that we hypothesize is that potentially, as civilizations, harness more and more free energy and are able to do more and more information processing and gain a sort of planetary level of sapience, I guess, you know, this idea that you understand the way that not just the planet itself is, is operating, but how you intertwined with the planet operate, that you can realize that you're on such a burnout trajectory and then reorient the way that your society works, such that you are no longer on such a burnout trajectory.

And we called this, what do we call it? Those asymptotic burnout and homeostatic reawakening, right, which is the idea that, yes, that where, how are, Yeah, so the homeostatic awakening is when you realize, okay, wait, we're headed toward burnout. We've got to reorient something about the way that our society functions so that we do not end up using infinite amount of energy and finite amount of time. And we prioritize the well-being of our society and our planet. And we enter a different sort of, it's like a phase transition into a different mode of being that might be sustainable in the long term, meaning very deep into time.

And so what we might want to then look for in terms of extraterrestrial civilizations that have quote unquote made it looks very different, I think, when then what we anticipate trying to look for in previous thought in literature, which is that, oh, maybe we should look for, you know, like type three civilizations that have like colonized the entire galaxy in this very, you know, almost naive sense that. all extraterrestrial civilizations will just naturally do what a subset of humans have done to our own planet in the past couple hundred years, but to the galaxy, right? And it's just like, but why should we expect that? Maybe what we should expect is civilizations learning to live more in harmony with their planetary environment and look for signs of that kind of planetary wisdom, so to speak, rather than just the continued expansion into outer space. There's some like implications for the Fermi paradox there. It was a fun thought experiment to just run through. So you're saying that not everyone wants to be a galactic empire? I would think, I hope. That's right.

Yeah. So I think it is potentially very naive of us to expect this mode of expansionistic empire, colonialistic, extractivistic mindset to just perpetuate into outer space without any checks and realistic hurdles that one will need to face. And I hope that our future looks a lot different from that personally, the future of human civilization. Well, that leads us perfectly to the very last question I wanted to ask, which is you have a podcast that you,

I don't know if it's still going on, right? Yeah, yeah, it's still going on. Tell us about your podcast. Okay, so two things that I can never stop talking about are science and Star Trek. And so I have a podcast called Strange New Worlds, a science and Star Trek podcast. And I started this in grad school when I was a little bit frustrated with the lack of science communication opportunities that I had. And it was just around the time that Star Trek was coming back onto the small screen through streaming TV. And I was listening to a bunch of Star Trek

podcasts. And everybody was talking about the character growth and the costumes and things like that. And I was just like, but what about the science? There's plenty of interesting science that's being displayed in Star Trek. And luckily, as a planetary scientist and astrobiologist, I had plenty of friends who were experts in these things that I could interview. And it ended up being a really kind of fun way of involving my friends and giving opportunities for science communication to my colleagues. But then it's grown into also just interviewing some people who have been on Star Trek,

portrayed science officers on Star Trek, and some of the creatives behind the show as well, who have written for Star Trek. And even the official science consultants, Mohab and Aaron McDonald's have appeared on the podcast, too, to talk about their influence on the Star Trek franchise. So that's been a lot of fun. And thanks for giving me the opportunity to plug that. Of course. I mean, I think it's a truism that there's a symbiotic relationship between science and science fiction, right?

I mean, they both help each other in important ways. And maybe that symbiotic relationship is, an autocatalytic cycle in our culture that is selected for because it inspires scientists to go and do cool things and discover new truths about the universe that help us as a society persist. At least that's a possibility. Well, you should write that paper and mention my name in the acknowledgments. I'm looking forward to. Yeah, I'd love to.

Yeah. Mike Wong, thanks so much for being on the Mindscape podcast. Thanks, Sean. So great. Yeah. Actually, you can cut this out if you want. to, but I also want to just tell the audience about how I first encountered your work. So if that's... Please, let's do it. So in, it was way back a decade ago, 2014, I was just a second year grad student at Caltech, and there was this very toss forum featuring a Sean Carroll.

And I don't know if you remember doing this, but I went there. And yeah, yeah, I was like, wow, this guy is amazing. Who is he? And I came away from that, just like, I need to read everything that this guy's ever written, and was so inspired because I feel like you were just so eloquent, and the depth at which you understood and were able to connect concepts in physics and philosophy. It was just super astounding. And so I was inspired, but I was also super intimidated.

I was like, that guy's great, but I also never want to ever have to be in a debate with him because you absolutely, you know, premed your competition. And then a few years later, I was part of this Star Trek parody musical at Caltech that your graduate student, Grant Remen, wrote and produced. And, you know, as we've discussed, I'm a Star Trek fan, so I absolutely had to be in this thing, even though I don't have a musical theater background at all.

So the good thing about Caltech is that, you know, it welcomes all sorts of people into the extracurriculars because we're all just nerdy scientists and you don't need to have any, you know, actual talent in singing to join one of these things. So I auditioned and I tried out. And I got the part of Sulu, which meant that I was at the helm, at the front of the stage, just like miming on the computer panel for most of the show and then singing some parts. And I, you know, the moment the lights came on the stage, you know, illuminates part of the audience, but just a part. And I saw you sitting like in the front row just a few feet away from me.

And I was like, oh, my God, I have to spend the next three hours singing in front of Sean Carroll, who I'm already intimidated by because he's a brilliant guy. And so that was sort of like how I was exposed to you. I'm so glad you didn't ask me to sing at all in this podcast. But hey, Sean, it's been absolutely a blast. I won't take up any more of our listeners time by explaining any more about how much I just admire your work, and thanks for having me on. Well, look, I'll confess, I had no idea.

I remember being there in the audience for To Boldly Go, right? Which is the name of the musical that Grant and his brother Cole wrote. And I remember your performance as Sulu very well, but I never remembered that it was you. I didn't realize that that was that Mike Wong. Okay, very good. So multi-talented, singer, Thespian, podcaster, scientist. Yeah. Thanks, John. Thanks very much for being here. This is great.