What's it like to be an alien?

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Speaker 1: When you look up at the night sky, you are casting your eyes on billions of star systems. It's a beautiful view, and it always makes me wonder about something. If the universe is filled with life, big, if, and if some of it is intelligent and curious, then are they looking back at us right now? Are we some bright dot in an alien sky. It's like that moment in the movies where someone is looking at a distant building through a telescope only to spot someone else looking back at them. If only other planets were close enough for us to spot alien astronomers gazing back at us like a cosmic meat cute. But even if we can't see them, they might be out there as ignorant about us as we are, of them, staring up into those alien nights and wondering if we are out there. Or maybe they're listening to an alien physicist on an alien podcast, or maybe they don't look or listen at all, and they experienced the universe in very different ways. Hi, I'm Daniel. I'm a particle a physicist and a professor at you See Irvine, and I hope that there are alien particle physicists out there wondering what we have discovered and eager to share some notes and welcome to the podcast. Daniel and Jorge Explain the Universe, a production of I Heart Media in which we explore all the questions being asked by humans. Whether you're a particle physicist, a dentist, or a long haul driver, we all wonder about how the universe works, and we all long to understand it. And on this podcast we ask those questions and do our best to answer them. But we don't pretend to know everything or to have all of the answers. One of our goals is to bring you up to speed, to the very forefront of human knowledge, so that you can share a spot with the rest of us looking into the abyss of everything that humanity does not yet understand, because we want to know how the universe works. We are a curious species, always wondering, and one of the things that we wonder is why do we wonder so much? Is it a natural product of being intelligent problem solving creatures or is it just us? We see other animals on Earth being curious. Dogs, cats, monkeys, dolphins all outwardly act as if they are intrigued by new things, by puzzles, they have not yet solved, which is why philosophers have long wondered what's it like to see the world through the eyes of a cat, or with the nose of a dog, or the echolocation of a dolphin. One of the most famous papers in philosophy is called what is it like to be a bat? The short version is we'll never know because a bat likely experiences the world very differently than we do. But bats don't have our intelligence. So cast your mind back out into space and wonder about that intelligent alien creature or blob or tree or floating ball of plasma that might be looking back at us. Can we imagine what their experience is like? So on today's episode, we'll ask the question, what's it like to be an alien? Obviously it's not a question we can answer today, but that doesn't mean that we can't make some progress. We can turn our minds back to the Earth and study the diversity of life here. It's random outcomes, it's consistent convergence is it's diversity and homogeneity, and maybe gain some insight into how aliens perceive and experience the universe. My co host and friend Jorge is on vacation this week, So I've invited a guest to come and join me in today's conversation about the alien experience. Dr Arik Kirshenbaum is a zoologist at the University of Cambridge. He studies the evolution of acoustic communications in different animals, particularly the role that communication plays in the evolution of cooperation. He works with a number of different species, including wolves, dolphins, and higher axes, and he's the author of the book The Zoologist Guide to the Galaxy. What Animals on Earth Reveal about Aliens. Now, we can't study aliens in the flesh, but if the principles that guided the development of biological life on Earth natural selection also apply elsewhere, then we can expect it may produce similar results. Not everything on Earth, of course, is inevitable. Some of the nature is random chance, media strikes and other pivot points. But some things crop up often enough that they may be inevitable even on other planets. I read this book and learned lot, and so I was excited to chat with Dr Kristen Boum. So it's my pleasure to welcome Eric to the podcast. Thank you very much for joining us, Thank you for inviting me. So I love that on your website you list the organisms that you study, and there's wolves, dolphins, higher axes, and aliens. Is it typical for zoologists to think about aliens? Is astro zoology and burgeoning field or are you the pioneer? It's not typical. It's not a burgeoning field. And you know, the field of astrobiology is big. The field of astrobiology is big and really burgeoning because you know, some of the some of the new developments that we've had, both in terms of instruments like James Webb and discoveries that can be made about the atmospheres of other planets and things like that has really pushed forward interest in the origin of life and and and the possible chemical nature of life on other planets. But also it's not just the instrumentation. You know, there's been a lot of breakthroughs really in new theoretical ideas about how life could arise. And so there are a lot of astrobologists around. There aren't really very many as rozoologists. And you know that's because, like you said that we can't actually observe any any alien animals, so so one might think as the much point. Really it's a bit of a waste of a career, but no as a as an evolutionary biologist, which is what I really am. The conclusions that I draw about evolutionary biology, they're generally applicable, you know, they apply on on other planets. I think people are going to start to come around to this idea. The understanding the ecology and the ecosystem and the evolution of life on other planets is something we have to start thinking about now that we're expecting to discover planets with some form of life on them. This is something we can't ignore forever. And I really appreciate that your book makes an argument. You know, a lot of biology books I read are fun and they're studied with cool examples that are interesting to learn about, but they don't always manage to tie them together into a coherent story. So briefly, is that the argument for your book that the process of evolution that occurs on Earth is likely to also guide the evolution of animals and critters on other planets so that we can make educated guesses about what they likely look like. Yes, it's and it's even a little bit deeper than that, because natural selection is just a process. Right we've known about natural selection for a hundred and fifty years, and it's just one of those things that's inevitable. It's going to happen everywhere. It's a very simple process. But what's happened in the last hundred and fifty years is that biologists have not just understood how evolution works, but they've understood that there are a huge range of other phenomena that arise once you start having natural selection in a collection of life forms, and the interactions between those life forms are really important. The way those life forms interact with each other, that's what's driving the diversity on this planet. That's why we've got so many different plants, and so many different animals, and so many different beetles. It's because of the way they interact with each other, and so understanding how those interactions are driving diversity give us some much more a much deeper understanding of those processes. And if those processes, those deeper processes are also taking place on other planets, then we can start drawing some really quite deep conclusions. Just give you one example, the simplest example in my book I think is predation. Right, all life needs energy. We know all life needs energy. That's just a physical constraint. Where you're going to get your energy. Might get it from the sun, you might get it from other places. But there's lots of energy around in the other life on your planet, and sooner or later someone is going to start taking advantage of other life forms and and and start eating them. And in that sense, by thinking about that, the way that the organisms interact with each other, we can predict things like, well, there are going to be predators, and there are going to be prey on alien planets. I really enjoyed this line in your book. I was going to call it out later. You write, predation is universal because no ecosystem can exist for long without someone trying to take a bite out of somebody else. The selected pressure on acquiring as much energy as possible is just too strong. That strikes me as maybe the experience of somebody who grew up in a household with brothers and sisters, you know, competing for enough food at the dinner table. But it's interesting because it's not an argument that I've heard anywhere else. Is essentially seems to be arguing that complexity arises also from interaction and competition that you're like unlikely to find an alien planet with a really sophisticated intelligent creature and nothing else, right, an ecosystem with just like a single organism, is it is that the argument that you're making, I think that's that's very true, and now that works on a couple of different levels. The thing about natural selection, of course, is that it has no foresight. So organisms don't evolve to be the best they can. They evolve according to the conditions in which they find them. If the conditions are simple, if the challenges they're facing a simple then they will evolve simple traits. Um if the challenges facing them are very complex, there may be an advantage to have more complex behavioral, more complex structure. So the complexity of individuals in an ecosystem really arises directly out of the complexity of the challenges they face, and those challenges are almost always to do with interactions with other organisms and other few other things as well physical environment. But basically what drives the complexity of life is the complexity of the of the interactions. So yeah, you're not going to get intelligent technological aliens evolving in deep space, for instance, which is a bit of a trope in science fiction. You know, You've got these aliens floating through space and they're super intelligent, but that's not going to happen because their ancestors never had any challenges to overcome and they know and any interactions they had to deal with, and so that that that kind of intelligence isn't isn't going to evolve. So yeah, yeah, I'm going with the interactions as being the key thing, and those interactions have to be with basically objects of another species. You can't just have interactions within a species. We're competing with your brothers and sisters for enough milk from your mother, for example. Well you can, but the implications of that are that some organisms will develop some techniques to deal with with that situation, and other organisms will develop different techniques to deal with with those challenges, and then you get a divergence and then you get speciation. And so it's almost inevitable that as the challenge has become more complex, you're going to get different different organisms. A system with all the same organism with complex challenges is very unlikely to persist for a long period of time. So you mentioned science fiction, Is that your experience when you read science fiction that agreetes on you because it doesn't reflect sort of the best thinking about how evolution might play out on other planets. Are you generally unimpressed, or if you read a few things that you think are actually insightful and contribute to the space of ideas, I don't I don't mind. I like science fiction, and I see its role as being a particular role, and its role is not really to inform on scientific hypotheses. And there are cases where people have made a really big effort to try and and and explore all kinds of potential ideas and potential situations using science fiction, and that's always welcome. But you know, I mean, I love a good Star Trek, and I don't really think that it's got much to do with what aliens are like. But that's okay that you know, that's that's not the end of the world. Well, Star Trek is, of course one of the most ridiculous examples, you know, humanoids that speak with sort of strange accents and funny terms of phrase and have wigglely boardheads. Are you familiar with the work of a. Greg Egan. He is a fantastic book that's one of my favorites, called Diaspora, in which they discover a water world that has a single organism in it, an algae that weaves itself into these weighing carpets that can break and reconnect in ways that actually make them a Turing machine. So that the complexity arises from the arrangement of fairly simple organisms. And you know, it's this kind of are they intelligent? Can we actually penetrate to them, can we understand what their experiences are they experiencing anything? Because the complexity arises from the combination of many organisms rather than inside a single organism. And this is a uh, this is another trope that that's quite interesting and has been explored by a number of science fiction authors. But again from an evolutionary perspective, the question has got to be why are these algae or Turing machine? How did that actually happen? You know, how did that come about? Because presumably they started with with simple algae that didn't have this complex structure. Somehow that complex structure must have come about. Now, did it come about because the algae that are organized into a complex structure were more successful and out competed the other algae. If so, there's a good mechanism that that that could have happened. But if they're just floating there and there's nothing much going on, it's it's hard to see how that could happen. So Fred Hoyle, sure you know Fred Hoyle, the famous astronomer or a fantastic science fiction book back in the fifties, The Black Cloud. It's really one of the best science fiction books ever written, and I love it dearly. But in the in the sort of introduction the forward to it to a recent edition that was written, Richard Dawkins absolutely toll or Fred Hoyle to pieces. He's dead now, of course, but tore him to pieces over his unrealistic biological assumptions that a cloud of gas floating through interstellar space could become sensured. There's just no challenges facing it, and no process of successive and progressive and gradual increasing complexity. That's what we've got to explain. If we want to explain alien life, that's what we've got to explain. So we're all, of course very interested in alien life and how it might arise, And of course we're all stuck here on Earth with no other examples to draw from. And you often hear people complain that this is you know, a single example and equals one. We don't know if what we have seen is typical or unusual. And in your book you take a different approach to this problem. Can you explain for our listeners how we escape the sort of in equals one prison. Well, the n equals one criticism is slightly disingenuous and equals one what one planet? That seems a little unrealistic since there are so many different forms on this planet. Really, what they're saying, I think is an equals one biochemistry, because that's really what unites all life on Earth, and we only have one example of a system of a biochemical system that can produce life. Apart from the biochemistry, there's sufficient diversity here that there's no justification for saying it's only one example. Is it a problem that we only have one example of one kind of biochemistry when when talking about alien life, Well, it's not a problem for me because everything I do totally ignores the biochemistry. You know, when you think about about evolution and natural selection and evolutionary biology, it doesn't really matter on what biochemical framework organisms are based. They can be based on DNA, they could be based on some other some other structure. People like to ask whether carbon chemistry is necessary. I mean, most people think that carbon chemistry probably is necessary, but that's from theoretical considerations, not from empirical observations. So I mean, I think you can criticize descriptions of intelligent life technological life on the basis of their only being one example, and that becomes particularly problematic when we think about language. So we only have one example of language, and that really is a problem. But I think to say that we only have one example of life is not really true at all. So the argument you're making is that we have many examples of life responding to similar circumstances, and for example, coming up with similar solutions wings on bats and wings on birds and wings on insects, for example, suggests that flight might be a common outcome of animal evolution. Is that the argument that's right? And if you want to take the unequals one complaint or objections seriously and honestly, then you would have to ask yourself, does the fact that birds and bats and insects all have wings is that fact somehow the result of some commonality the equals one commonality, the fact that they are all on the planet Earth, or the fact that they are all based on carbon chemistry. Is that does that really explain this commonality of wings? And it's almost impossible to answer yesterday. It's very hard to see how the fact that wings evolved independently three times could really possibly be based on the commonality between these organisms. The only thing they have in common is that there are bilaterally symmetrical, so they have one wing or two wings on each side of their body because they have an access of symmetry down the middle. They have a left side and the right side, and that certainly is sheard. All those three organisms evolved from a common ancestor that was symmetrical. So that's potential argument. But my counter argument that is that symmetry is so incredibly useful that we're going to see it on other planets as well. So to make the argument that the kind of things we see on Earth are likely to also crop up in alien animals, what assumptions are we making exactly? Let's be explicit about them. Were assuming that evolution is a universal process that happens here, it's going to happen everywhere. Aren't you also requiring that the conditions are similar? I mean, evolution is as you say, in response to the circumstances, are we assuming then that there are rocky planets, that there's air for things to learn to fly through? For example, I think the two kinds of assumptions based on what you mean by life being similar to life on Earth, I think that there are assumptions that support the claim that evolution and natural selection and all these processes that we understand very well from life on Earth, that they will apply on other planets. There are certain assumptions there, and those are assumptions like the basic assumptions of natural selection, that organisms reproduce, that organisms vary, that they're different in their characteristics, and that they can pass that difference on to their offspring, and that those differences have an effect on on how they survive and reproduce. And those are the basic assumptions of natural selection. As long as those assumptions are met, natural selection will occur. Can I stop you there and ask you about one of those passing information onto your offspring mean that fundamentally is rooted in the biochemistry of life on Earth, right? Can you imagine a different fundamental biochemistry for a life that has a different sort of process for passing along information that might lead to widely different sort of higher level evolution. Unfortunately, if that condition isn't met, then we've lost the most important feature of natural selection, which is that complexity can accumulate. If organisms reproduce to duplicate whatever word you want to use, but don't pass on their own traits to their duplicates, then complexity cannot accumulate and you'll just be stuck in a soup of chemicals, never becoming life. So I say that these assumptions are our conditions for natural selection applying and occurring. But if they don't apply, and if it doesn't occur, then complexity cannot accumulate. So the conditions for natural selection occurring are are It's a little bit unfair of me because I am actually assuming that they are met. But then the other thing is the other direction to take it is that just because natural selection in theory occurs doesn't necessarily mean that life will achieve the kind of complexity we see on Earth. So, for instance, people have speculated that there might be life on the surface of Titan, and Titan with its lots of flowing liquid water and rivers and lakes and mountains and so on, and the fact that this liquid is not water, is irrelevant, really invented by a chemistry based on ethane or something like that. The problem is that whatever it is minus a d eighty degrees on the surface of Titan or chemical reactions will be extremely slow, and in that case, even if there is life on Titan, it really won't have had time to evolve the kind of complexity that that that we see on Earth. Life existed on us for over three and a half billion years, and for the first three billion years it was very, very very simple, So it really took a long time for complex life to get off the ground. So just because these conditions are met doesn't mean will necessarily see something like Earth. But isn't that another example of the inequals one argument. I mean, we know that life started fairly rapidly on Earth and that it didn't become complex very rapidly. Can we conclude from that that, you know, one, life is likely to start in other places because it happened rapidly on Earth and that complexity does take a long time, or were we just unlucky? So the argument that we don't know how likely it is for non alive chemicals to become alive, we don't know how how likely that spontaneous change is. Has has been a very good argument for the equals one position, and things have changed a little bit in recent years for a couple of reasons. One, of course, we've discovered so many planets. I mean, there's just so many planets. We never thought there would be billions upon billions of Earth like planets in the galaxy. So the numbers game changes a little, but it doesn't alter, of course, the fundamental objection that maybe life on Earth was a tremendous fluke and it's just not replicated anywhere else. But recently, and as I said that, the field of astrobiology has become very, very big, and a lot of people working, there's a lot of scientists working on the question of origin of life, coming up with a lot of hypotheses that seemed to indicate that there are potentially many routes to life arising from non life, different by chemical propositions, different ways of getting chemicals to combine stably and make reproducing molecules, and and and so on, and the general feeling, although of course it's not proven, is that that the probability of life arising from nonlife is probably not all that unlikely. Wonderful. Well, I have a lot more questions about how that all works, But first let's take a quick break. All right, we're back and we're talking to Dr Eric Curson bomb about what aliens might look like and how they might crawl across the surface of their alien planets. And we've been talking about the likelihood of life starting on other planets, and also the likelihood that it looks similar to ours, whether it shares with us movement or communication or intelligence or these kinds of features. And I want to get back to a question I think I interrupted your answer, and I want to hear more your thoughts on this about the likelihood that life arises in our kind of context. You're absolutely right that there are billions of planets just in our galaxy, and many of them are rocky, and many of them are likely to be in a region where there's enough solar radiation to make water liquid on the surface, etcetera, etcetera. So there are many situations like Earth where life might arise. But does that mean that's the most likely place for life to arise? What about places like underground oceans that we have even in our solar system? Do we know if alien life arises, that it's most likely to arise in our kind of circumstances. We certainly don't um and as you say, underground oceans are tremendously interesting environment where we would love to explore. We are, of course somewhat limited at the moment that with our tools that are capable of looking at the taking spectrographic measurements of the composition of of the atmospheres of alien planets, that somewhat limits us two planets with reasonable atmospheres, you know, in the future. Who knows. The first indications of the sub underground oceans on on en Seladus and Europa came from observing, you know, plumes of water escaping from from underground. That may even be possible in the future with with extra planets to imagine, but it's possible. And there's been some very very interesting and peculiar suggestions from scientists, from astrobiologists about different places that that life could exist study I've heard recently a suggestion that even gas planets like like Neptune could possibly host a band or sphere of liquid water at some level in their atmosphere, so that there are many places where conditions for life might be right, and because we're still we're still far from finding out exactly what pathways led to life arising on Earth, I think it's a little bit optimistic to be to be examining those weird environments as well and trying to figure out how life might have arisen on Neptune or or or in Zeladus. But we'll get that. But in the context of the arguments in your book, for example, it seems like the assumptions were making are that evolution happens and all the details of you they are previously, and also that we're talking about sort of a similar kind of context, right, that evolution happens in the kind of biological context that we've experienced, and and we don't need to assume that that's dominant or that it doesn't happen in other context to explore what life might be like on an alien, rocky planet with water. So two things, two things to say to that. One is that when you say that the context and I presume, I mean things like, well, the fact that organisms are close to each other, that they can interact, that they're not spread out over obscenely larger area of volume. That's actually quite an easy assumption to make because again and said before about accumulating complexity, if those organisms aren't interacting, they're not going to evolve. They're not going to evolve into into the kind of complexity that we see. Then maybe alien equivalent to bacteria spotting it here and there on the surface of some planet that can't interact with each other, but there's no reason for them to evolve into more complex life forms if they never interact with anything. So I think that it's true that there are certain assumptions about about interactions and so on that I make, But that's with the hindsight, with the retrospective assumption that there will be complex life there and not just bacterial life. But the other thing that I want to say that I always have to say because it's really important to be humble about these things. There will undoubtedly be examples where I am completely wrong. I have no doubt about that, But those examples are gonna be really rare. Right. The galaxy is full of rocky planets like Earth with water on the surface, and it's full of carbon chemicals, and life which shares a lot in common with life on Earth, will be common. Sure, they'll be there'll be weird stuff. There'll be weird stuff that it's never thought of and no one has ever thought of, but that's going to be rare. Water is exceptionally common in the universe. Common chemicals are exceptionally common in the universe, and so I think it makes a lot of sense that something rather like what we see here is not going to be uncommon. Absolutely, And the argument you're making seems to be built on these convergences, these suggestions that these kind of things happen several times on Earth, so we don't have just any equals one. These are things that seem more inevitable than rare. But there are also examples here on Earth of pivot points and wins when faith took us one way and it might have gone another. You know, we have these moments in our lives. You know, when I was deciding where to go to grad school, I basically flipped a coin between two universities, and because I went to one, I ended up meeting my wife and I have these kids in My life would be very different if I hadn't gone in those other directions, you know. So can we also look at the history of life on Earth and identify those pivot points and say, if this thing about life on Earth is unlikely to be found somewhere else because it arose from this random weirdness, can we also make those kind of observations, not just find the commonalities. Well? Possibly, But I loved your example. If the coin had gone the other way, no disrespect your wife and kids, you probably would have found another wife and had other kids, right, and it still would have happened. And in that sense, I think it's a pretty good illustration of of of the convergence. Are there pivot points on Earth that led to very particular configurations of life on Earth? It's hard to think of that. I think the major pivot points on Earth, so the major mass extinctions, which are really the ones that people talk about. If you think about the Permian mass extinction, which was huge, like n of species went extinct. When life rebounded after the Permian mass extinction, it really wasn't all that different, It really wasn't. I mean certainly that that that mass extinction was a huge push and in the way that diversity developed and evolved over over the millions of years afterwards, and there's no doubt that we wouldn't have dinosaurs, and we wouldn't have primmates, we wouldn't have humans if it hadn't have been for the Permian mass extinction. But if you look at the animals that lived afterwards and the animals that lived before, they're different, But all the niches are basically still the same, basically very very similar sort of stuff going on. So clearly there are physical characteristics of Earth that determine what kind of life we have. The density of the atmosphere, the transparency of the atmosphere as well as a huge is a hugely important one in the nature of our ocean, determine the kinds of life that flying in the air and swim in the sea. But that's really the response to physical constraints constraints on on the environment, rather than the pivot points per see. And what about the one that's mostly to our hearts, you know, intelligence, you're saying that the niches are effectively the same before and after. You know, the common story that you hear is dinosaurs were wiped out by this meteor, which might have also missed Earth if had you been pulled gravitationally by another object, And that because the dinosaurs were wiped out, there was room for maimals to flourish. Dot dot dot you get humans and technological life. Are you suggesting that even if the medior hadn't hit the earth, if the dinosaurs hadn't been wiped out, that something would have arisen that was intelligent and technological not not an easy question to answer without a time machine and interfering with the course of history. But we've got some clues, right, so we can look, for instance, at if you look at a plot of the diversity of life on a since the Permian mass extinction, you'll see a pretty linear increase. I mean, it's just going up and up and up. And it's true there was a dip when that media hit and there was a nice big mass extinction there, and then diversity just kept on climbing again. So it's almost as if it just with the simple metric of how of the diversity of species, it's almost as if it didn't make much difference. You know, it changed things a little bit, maybe, but the increase in interactions between species just kept on going up. Is it possible that it could have flatlined at that point? I suppose as possible, but it seems really unlikely. Okay, it does it does seem unlikely. It's true that we can invent all kinds of stories about exactly what happened after the dinosaurs went extincts can't be very confident about them. But you know, the usual narrative goes that these nocturnal mammals all of a sudden didn't have to be so scared about coming out during the daytime, and so they could exploit niches that weren't available to them before, and so they diversified and so on. It's very hard to imagine that this kind of radiation wouldn't have happened at some point. It just seems like the opportunities were there, and opportunities get exploited in evolutionary time, they really do. That might be the first time I ever heard somebody say the phrase nice, big mass extinction. But I suppose from an evolutionary biologists that is the way you look at it. Well, I want to dig a little bit more into thinking about the details of animals on alien planets, because you go well beyond these sort of general arguments, and you talk very specifically about what we can learn about alien animals from animals on Earth. And I want to focus first on senses. You know, here on Earth we have a wide variety of senses, but humans don't have all of them. Right, There are certainly senses that exist in the animal kingdom that don't exist in humans. What can we say about what aliens might experience? Are they're likely to be able to sense magnetism the way birds do, or sense electric fields the way fish can do. Things about senses sensors are really interesting. One is that centers um really really constrained by physics. Right, there's just some things that you can and can't do. In a vacuum, you're not going to use sound, it's not going to happen. So you know, in an opaque atmosphere, you're not going to use light. So there's a lot of stuff that's really easy to predict just based on the physics. But as a biologist, I don't want to spend too much time talking about physics. And from the evolutionary perspective, there's another really interesting thing about senses, which is that senses evolved because they gave an advantage. They gave an advantage to some organism. Now, typically that advantage would be finding food. So if you have an amba and it's in water, and it detects a concentration gradient of of of nutrients and it can move up that that concentration gradient because that ability gives it a definite advantage. It gets more food that way. And senses have to be understood in terms of what advantage they give. It's a huge you know, it's this huge idea that aliens are going to have these super senses and they're gonna have these wonderful things that we don't even imagine, and they can they have all these incredible abilities that we can't conceive. Or maybe, but only if it gave their ancestors an advantage, only if the organisms from which they evolved, and probably the organisms from which they evolved a long long time ago. You know, they had to have the advantage. If you look at all the senses that exist primarily in animals today, They've been around since the simplest animals. Sensing is a really crucial thing for animals. I should probably mention I'm sure we'll come up against this again when we talk about intelligence, but I should probably mentioned why I talk about animals all the time and what I mean by animals, because animals are something quite different. You know, animals have a big challenge, which is moving around and finding food and avoiding becoming someone else's food, and finding a mate, and all the spatial constraint where do you go and how can you go? And where can you go? Really drives a lot of complexity in the animal world because they need to solve these spatial problems. Sensing is a is a perfect exam of the reason that animals sense and plants sensors are much more simple than than animal senses because plants don't need to move. Animals need to decide do I go left or do I go right? Now? Aliens may have organisms that look like plants that you may have animals like groot right, that's a plant that moves around. I would call that an animal because for me, an animal is something that has to move and make decisions about moving in the moment you have to make decisions about moving. You need sensing. You need to be able to sense the world around you. And so why, for example, did our ancestors not need to sense electric fields or magnetic fields, but the ancestors of birds and fish did. Can you not imagine any circumstance in which that would be an advantage to us using electric fields to sense the presence of fish, for example, in water, you know, while hunting in shallow lakes. Is there no circumstance in which case those other senses would have been an advantage to our ancestors are And just as though our advantages to us having wings, right, who wouldn't want wings? And not saying it's not an advantage, But the evolutionary path that we followed is constrained by what our ancestors constrained by the cost benefit analysis of our ancestors. So you know, our ancestors were better off evolving big guys that served them much better than an electric sense. Electric sensing is really really complicated. It's very very difficult. It requires very very specific organs in your body, and if you really don't use them very much, then it's just not worth it. So our ancestors didn't benefit at all, wouldn't have benefited at all from electric sensing, and so they didn't have them. But we might like wings now, you know, you might even think that our ancestors could have benefited from wings sort of climbing through the trees in the jungle, but they were constrained by their ancestors as well, and not the simplest thing in the world to evolve. Wings to the process of evolution always involves these cost benefit trade offs, and in that cost benefit analysis, it's just it just wasn't worth a while. It just wasn't worth our ancestors, our ancestors. While So your comment about aliens and their supersenses, I take that to be an argument that probably alien animals will have some subset of the kind of senses we see here on Earth. That there isn't some new, amazing sense that they have evolved that we've never seen before. Well, that's a question for you, right, that's where the physics comes in. That's constrained by physics. It's true that animals on Earth use pretty much all of you known that the senses that we think are possible through our understanding of physics. Magnetisms are really a really rare one. It's a bit of it, right, but it's not it's not hugely important. But you know, earthlings use use pretty much everything. Is there another sense out there, like gravitational sensing or something, or neutrinos sensing? Maybe? I don't know, tell me. So that was the next question I wanted to ask you about, and I'm particularly struck by the example of magnetism. I mean, here's an example where a creature develops a sense to something that's very subtle and hard to pick up. You know, it requires a really delicate chemistry to happen in their eyeballs for them to be sensitive to these magnetic fields. And at the same time, we know from the physics at least that a lot of the universe is invisible to us. Right, we are surrounded, as you say, buy neutrinos. A hundred billion passed through every square centimeter per second, and they carry a huge amount of energy. It took a long time on Earth to develop vision and photosynthesis. Is it possible that if we waited a few billion years that plants would develop like neutrino synthesis, where microbes are learning to eat energy from neutrinos somehow? Is it impossible to imagine or do you think it's just sort of hasn't happened yet here on Earth? Impulsibles big wood, but improbable is a reasonable world. And the reason is that natural selection only works when it provides concrete advantage every step of the way. Right, You've got to have an advantage by having half a neutrino detector, And given that a neutrino detectors probably pretty complicated, you'd have to explain why having some sort of very simple, primitive ability to detect neutrinos would be an advantage, and that's very hard to do. One of the nonsense arguments against evolution is that, well, how could you evolve an eye? And half an eye is not useful? Half an eye is incredibly useful. You know, the very simplest organisms that were able to detect a shadow from a bit of light had a huge advantage, a huge advantage over over other organisms. So you would need to see something like that with one of these extra senses, one of the ones that hasn't been detected. You'd have to see a real advantage for that very simple innovation. All right, and I have lots more questions about what it's like to be an alien and experience the universe. But let's take an their quick break. Okay, we're back, and we're talking to Dr Arika Kirshenbaum about his book The Zoologist Guide to the Galaxy. And I noticed that you say the Guide to the Galaxy. Is that a tip to Douglas Adams instead of thinking about the guide to the universe. It is. But then again, even astrobiologists, and I mean like the based astrobiologists, unlike me, really our thoughts are pretty much limited to the galaxy. The galaxy is something we can know about. Unless we're talking about highly advanced technological civilizations in other galaxies, we'll never know about them. Yeah, this is I think the galaxies are really reasonable laboratory in which to work. It is true that while there are chillions of other galaxies out there, there are millions of light years away, whereas our galaxy is only tens of thousands of light years across, and so they do seem frustratingly distant. And so we were talking about sort of how aliens might sense the world, and you're making the argument that we use most of the reasonable seeming senses and everything else is probably unlikely to arise because it doesn't convey a benefit at every stage of evolution. And we talked about neutrinos, for example, and you know, for the folks and the audience who are interested in physics, we know, for example, also that the universe is filled with dark matter, and that there's kinds of radiation out there that we cannot sense directly, but we've developed these technological eyeballs in order to discover them and to see that they are part of our universe. And so I think the argument you're making is that it's unlikely for these things to naturally arise biologically in aliens unless they have a pronounced benefit along every step of the evolutionary path. And in your book you make this argument specifically about how this impacts alien civilization, and you say, for example, that alien civilization will probably rely on vocal communication rather than say, community action of complex ideas using sense. So I want to dig into that a little bit more. How building on this basic experience and sensory networks, that's likely to impact the structure of alien and civilization and alien intelligence. Yeah, and it does sound a bit too radical of a suggestion, doesn't it. The alio aliens are gonna talk like us a bit of a coincidence, But then again, you know, we are constrained by physics here. There are only so many different ways that you can convey information, and so many different channels, so many different media. There's light, this sound, there's smell, a's touch, there's vibration, there's electrical fields as magnetic fields. The list is not a lot, and I'm sure that that that entire list will be exploited by organisms here. They're everywhere across the galaxy. The question is which of those channels can be used for complex communication because technology relies on complex communication. You want to build a spaceship, want to build a radio telescope, right, you need the instructions manual. You need to be able to say this part goes plugs into into that part. So there needs to be the capacity to have a certain level of complexity. Which of those media, which of those those physical channels support that kind of complexity. Well, you know, I argue that that smell probably doesn't. There are a lot of problems with using chemical cues for communication. Loads of animals do it right. It's it's one of the oldest forms of communication, but it's always going to be simple. Smells get mixed up, they travel very slowly. It just doesn't sound like it's a reliable channel for conveying information. Vision and sound really are the two that that can hold a lot of information and are reliable over over reasonable distances. And the third one, which is really reliable and can hold even more information, is electrical fields. It seems like those three channels are the only physical channels that are capable of carrying enough information really to be a complex language and to convey complex technological ideas. We use the first two. Of course, we don't use electrical fields. There are some animals on Earth that do not many and that's really because it's actually very challenging. It's a very challenging thing to do. But I don't doubt that there could be technological alien species that have an electrical communication, electrical language. And so we're building up an argument that suggests that aliens probably move their complexity arises from competition among these bits all trying to eat each other, that they're probably communicating with each other. Does this give us enough of a sort of complexity soup to suggest that intelligence is likely to arise? How much of a reach is it to suppose that this kind of context will lead to alien intelligence. Well, for a zoologist, it's it's no leap at all. Right, A zoologist will tell you all animals are intelligent. Intelligence is a fundamental property of animals, because if we define intelligence as the ability to solve problems, that's precisely what animals have to do. They have to solve problems. They have to decide whether to turn right or to turn left. They have to find food, They have to decide whether an image that they see on their retina is a potential food source or or an animal coming towards them to eat them. Those challenges which are critically I mean, the important thing about those challenges is that these challenges are time critical. Animals have to make decisions quickly, straightaway. Is it a predator? Should I run? Should I turn left? Should I turn right? And that's intelligence. That's precisely what intelligence is. So so the simplest, simplest animal has intelligence. Now, of course you're going to say that's not fair, that's not what I meant. I meant intelligence like us, I would define human intelligence in the way that you want it to be defined. What you're really asking about is technological intelligence. Okay, there's this joke from SETI scientists that I like to tell, which is that there are two kinds of organisms in the universe, folks and critters. Folks is anyone who can build a radio telescope and criticism everything else. And the rational behind that is there might be some really intelligent alien species out there really fantastically clever. If they can't make a technology to send signals to us, we'll never know. I will never know about them unless they come and visit, right, Yeah, but they'll need that technology then, now, okay, they'll have to have that technology or will never know about them, build a radio telescope, builder, spaceship, whatever. So there is a criterion which is an interesting criterion. I wouldn't call it intelligence, because, as I said, all animals are intelligent, but there is an interesting criterion of this technological intelligence, the ability to build a radio telescope, the ability to build a spaceship come and visit us. And I think that's what you're asking, Is it something like that? I mean, essentially, I want to get to the question of whether we can make a mental connection with these aliens. How likely is it that we have enough in common that we could communicate with them and get some insight into what I think is the deepous question, which is what is it like to be an alien? How different is it from what it's like to be a human, And can from that we draw some interesting conclusions about, you know, the nature of consciousness and intelligence itself. If we find aliens to be very similar to humans. If we find them to be just alien enough that we can understand them, but they're weird enough that we can learn something about the nature of intelligence, I think would be especially interesting. So one thing I really appreciated about your book was this exploration of what we mean by intelligence, especially a part in your book where you argue that if aliens are found to be as intelligent as humans, might we consider them to actually be human. Right, you can imagine granting them rights and treating them as persons. So what do you think that we can say about alien intelligence based on what we have learned here on Earth? And is it just philosophical or is it built from a sort of argument about the experience of aliens the senses that we were talking about earlier. Well, of course, it seems very very unlikely that will ever go and there's an ali in planet and look at the different alien animals on it will be wonderful, But it seems unlikely. But if we were the Thought Experiment and we were to land on a planet, okay, most of the planets with life are just going to be bacterial slime, right, probability is a vast majority there's only been bacterial slime on Earth for two and a half billion years, and and and so chances are alien planets, most alien plants are going to be like, let's say we find one that's got complex life, and we land on that planet it's got complex life, and we look around. I claim that we will see things that appear to us the equivalent of trees, things that appear to us the equivalent of animals. Those things that appear to us the equivalent of animals will have a wide range of what we think of as intelligence. There will be slug like creatures that don't seem to have very much intelligence. There will be primate like creatures that seem to have considerably more intelligence. So I think that that diversity of intelligences is very likely to occur, and I think we would wreck ignize it. I think we would recognize the parallels with animals on our planet, because of course, intelligence will arise for exactly the same reasons as as it arose on on Earth. However, now you're asking about the technological aliens. If we can even find any of those, what are the chances that we will have basically common ground with them? It's a completely different question whether we will ever be able to learn their language, But put aside for the moment, but assuming that we could learn their language, would we be able to talk to them, would we be able to understand them? Would we be able to understand the psyche experiences? You know, if if they do use electric fields to communicate their view of the world, if you can call it a view, maybe we need to think of a new word that's kind of electric view. If they sense the world using electric fields, their perception is going to be so utterly different from ours. Would we find common ground with them? And I think you can probably guess that my aunt's there is going to be yes. And the reason that my answer is going to be yes is because if we were lucky to find such a species, the only reason they have an intelligence that is similar to ours is because they've been through a similar evolutionary history to ours. That's the only reason they would have it. Right. We don't exactly know what caused our ancestors to evolve the intelligence that put us in the place that we are now and the mess that we are now, But whatever that pathway was, it's quite likely that a similar and identical similar pathway will have evolved for these intelligent aliens. And if that's the case, then yeah, there is common ground. That seems to me a strong argument. But I also think about the kind of experiences of intelligent animals here on Earth, and I wonder about the very kind of argument you make there where you say, let's look at the variety of things we see on Earth. And you know, as we look around on Earth, we see fairly intelligent creatures that we think might have very different sort of mental internal states. You know, take for example, an octopus that has like a central brain but also seems to have semi independent arms that it passes instructions too, and then they execute them. However, they like, what is it like to be an octopus? It seems like it might be very different from the experience of being human, and that kind of barrier, that kind of different flavor of intelligence might prevent a barrier to real effective communication and you know, technological transfers. But then again, there's a barrier between us and and those animals on that we can't understand what it's like to be an octopus, right, we can't understand what it's like to be a dolphin. Why not because they don't have a language. It's because they don't have a language. I mean, if you could go up to an octopus and ask what's it like to be an octopus? You might find its answer somewhat confusing, but at least you get an answer. At least you'd have an insight into what they're thinking. And it's language that's really the key thing here. In language is the only way that we can interrogate the minds of other creatures in any detail. We can do experiments, There are experiments we can do. They are very clever experiments that we do to investigate to what extent animals understand themselves, to what extent animals understand that other animals are different individuals, and so on. But really, if you want to know how you're feeling, you know, what do you what do you think about this poem or whatever? That requires language? And now the question is are these hypothetical technological aliens of ours going to have language? Yes, technological they have language. You cannot write that spaceship Instructions book without language. You cannot build a spaceship without language. You have to say to another alien, you know, asked me the screwdriver, so that barrier that exists between us and other intelligences on Earth is a real barrier, and I agree that there are many kinds of intelligences that will be hard to understand, but at least we would have that window. May not help, may not solve the problem. We may find that that alien talking octopuses are so different from us that we simply cannot understand what they're thinking, but at least it gives us a chance. At least it gives us a window. I agree that if they're technological, it's likely that they have language, But then the question is what are the chances that they are technological? And isn't there a naive argument to make that it's unlikely that we see lots of intelligence, even fairly strong intelligence on Earth like OCTOPI that isn't technological, and only one example of the case that it is ours, and therefore it's unlikely for aliens, even intelligent aliens, to be technological on other planets. Yeah, but unfortunately, that's back to the critics argument. We would never know until we can, until we can get to those planets and count how many intelligent animals there are that haven't developed spaceships that unfortunately is a closed door to us. All talk about about talking to aliens, communicating with aliens, meeting aliens. This is all very much based on this hypothetical situation where we find highly intelligent technological aliens that that will talk to us. How likely that is we have to be a smeistic I'm afraid. So then my last question is more about you, which is why are you interested in this question, this hypothetical question of alien life? Your zoologist? Are you plenty of examples for things to steady here on Earth? Why I spend time wondering about alien life? Why not just wait until we do discover it and then you can talk about their concrete details. Why did you write this specific book as it happens? This is really it's really the subject that we just touched on. I research communication, That's what I do, and I'm interested in things like how much are our animals saying? How much are they saying to each other? How complex are the messages that they passed to each other? Big question? You know, are humans the only ones with language? And to answer those kinds of questions, raises to investigate those kinds of questions haven't exactly got answers yet to investigate those kinds of questions means we need to look at some very fundamental ideas. What is language? What is communication? Which is meaning? Right? What's the meaning? You can you have meanings without language? Does that even make any sense? Does an animal does it dolphin? Mean something when it makes particular sound? And so looking at these questions and trying to find ways to answer these questions and trying to find ways to ask animals the answer really does touch on the kinds of issues we've We've just been talking about, what is the difference between the mind of a human and the mind of a chimpanzee or the mind of a of a parrot? Why are we different? Actually? In what way are we different? Are we different? Clearly we are. We have language? How has that come about? Why has that happened? Is inevitable? As you say, maybe a language will never arise on any other planets, or maybe you will. Maybe it is inevitable. Has it arisen before on Earth? Is it only humans? These are the kinds of questions that I deal with on Earth, but you can see that they have they have implications for thinking about who are ever going to talk to? If we're ever going to meet anyone. No, I absolutely I agree. I think that framing it in terms of what's going on on other planets is a great way to think about with unique on Earth, what's special on Earth, what's common on Earth? And so really we we can learn a lot about ourselves and so um I learned a lot of reading your book. I really enjoyed it, and thanks very much for coming on the program and answering all of our naive questions. Yeah, the great questions. I love that well, Thanks very much, and I encourage all our listeners to check out the book again. It's called The Zoologist Guide to the Galaxy and the author is Dr Arik Kirshenbaum. Thanks very much for joining us today. Thanks for listening, and remember that Daniel and Jorge Explain the Universe is a production of I Heart Radio. For more podcast for my Heart Radio, visit the I Heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.